Swarming Squid Sperm: A Strategy in Sneakiness

Sneaky swarming squid sperm. Yeah, let’s talk about that. ‘Cause you hear that and you gotta know, right? But before all the sperm and the swarming is the amorous squid. Let’s start there.

As you may expect, squid have both a male and a female. Male squid produce spermatophores, packets of sperm that they can transfer to the females. Female squid carry around these sperm packets until they are ready to spawn. That can be quite some time in some species. When they are ready, they will use the stored sperm to fertilize and then release hundreds or thousands of eggs into the water as jelly-like strands. That’s about what we know about squid reproduction, the rest is relatively mysterious.

A newish study in Current Biology sheds some light on the mysterious nature of squid sperm. The study organism is Loligo bleekeri, one of the more common of the pencil squids (Loliginidae) in Japan and southern Korea. It is moderately large (40 cm) with very short arms. It is a polyandrous species, meaning that males only mate with one female, but females mate with many males. It is a good mating system for researchers interested in mate choice and sperm competition (oh yeah, there’s a whole subdiscipline of the science of sperm competition – rethinking your job now aren’t you?). These have been shown to drive sperm evolution (yes, that’s a thing) and morphology to optimize fertilization success. Because in this game, it’s all about how many babies you have.

One of the things that makes this squid species particularly interesting is the dimorphism among males. Large “consort” males do all the work. They compete with other males, court females with colorful body displays, and guard the female until she spawns his offspring. Smaller “sneaker” males are just that: sneaky. They rush in under the nose (or beak, as it were) of the consort male, attach their spermatophore and book it on outta there. The dimorphism in males is reflected in their mating as well as their size. Consort males place their spermatophores inside the female’s oviduct, while the sneaker males just stick it onto the external body surface near to the seminal receptacle near the mouth. It isn’t as close to the eggs, but it must be a successful otherwise why do it? What is it that makes this stick-and-ditch strategy so successful?

To find out, the researchers dissected consort and sneaker males to recover their spermatophores. Then sperm were released into test tubes, diluted and tagged with fluorescent labels (each type with a different label). They observed that when the sperm suspension was drawn into a capillary tube the sneaker, but not the consort, sperm aggregated (or “swarmed”) to form a regularly striped pattern along the tube. And, when sneaker and consort sperm were mixed, still only the sneaker sperm swarmed. The sperm weren’t slowing down or sticking together, so what was causing the swarming? It’s not like the sperm are problem solving. So the next thought was: Maybe it’s a chemical response. So a filter assay was designed where two chambers were separated by a filter so fine that only small molecules could get though. A sperm suspension was put into the lower chamber and then each type of sperm added to the top to see where it swam. Again, only sneaker sperm migrated toward the filter. Okay, so it must be some kind of chemical attractant, but what and how?

Again, labeled sperm suspensions were put into capillary tubes. Then bubbles of different gases were microinjected into the solution. This assay revealed that carbon dioxide (CO2) attracted sneaker, but not consort, sperm. This CO2 is likely generated by the sperm via the carbonate system. Not exactly a super-simple system. To tease apart the mechanism, they developed caged carbonate (you’re thinking Han Solo…me too, but not quite the same) to sculpture gradients of bicarbonate (a basic solution, pH-wise). This system allowed them to determine that swarming depends on acidic (CO2 and/or H+) gradients but not on a biocarbonate gradient. Next, they found that carbonic anhydrases (CAs) are involved in swarming as CO2 sensors in cells.

But let’s go back to the acid thing (as both CO2 and H+ increase acidity). The researchers used a pH-sensitive dye to look at the acid gradient during swarming. They observed that the middle of the swarm acidified first, producing a H+ gradient outwards. When they added a buffer, the swarming disappeared. When they put a pipette of acid (H+) into the suspension, both sneaker and consort sperm moved toward it. But remember that only CO2 attracted the sneaker sperm. Additionally, the pH at which these types of sperm responded was different. They found that only sneaker sperm lowered their intracellular pH with environmental pH. This means that only sneaker sperm have a H+ transport system that allows for the CO2 attraction. And finally, they showed that calcium (Ca2+) influx controls cause the sperm to turn around when they reach the end (weak part) of the gradient.

Whew! That’s a lot of compact information! So let’s put it together in a whole-organism, what-the-heck-is-going-on kind of way. Why does it matter that sneaker sperm like CO2? Remember back to the placement of the spermatophores by each of the males. When the female releases her eggs, the consort male’s sperm has first access because it is in the oviduct. They fertilize a lot of eggs but not all. Then the female holds her eggs in her arms while she swims to a good substrate to release them. Squid arms and mouth are not all that far away from each other. This is when the sneaker male sperm goes to work. The swarming allows the sperm to stay close to the site of egg deposition and may be sensing CO2 released from the eggs; both increase the chances of fertilization. And, in the end, that’s what it’s all about.



Hirohashi, N., Alvarez, L., Shiba, K., Fujiwara, E., Iwata, Y., Mohri, T., Inaba, K., Chiba, K., Ochi, H., Supuran, C., Kotzur, N., Kakiuchi, Y., Kaupp, U., & Baba, S. (2013). Sperm from Sneaker Male Squids Exhibit Chemotactic Swarming to CO2 Current Biology, 23 (9), 775-781 DOI: 10.1016/j.cub.2013.03.040


And for a little more info, here's an earlier study on the same topic:


Iwata, Y., Shaw, P., Fujiwara, E., Shiba, K., Kakiuchi, Y., & Hirohashi, N. (2011). Why small males have big sperm: dimorphic squid sperm linked to alternative mating behaviours BMC Evolutionary Biology, 11 (1) DOI: 10.1186/1471-2148-11-236



(image via MarineBio.org -- Note that this species is Loligo vulgaris, the European squid. It is weirdly difficult to find images of L. bleekeri, but this image gives you some of the characteristics of the genus.)

Falling with Style: Controlled Gliding in Spiders

Sometimes I read a paper because the methods catch my eye. I can just imagine some scientists sitting around a table with a beer and saying, “I wonder what would happen if we just dropped a bunch of spiders from the tops of trees.” An article published online yesterday did just that.

Barro Colorado Island is a man-made island is located in Gatun Lake, created by filling of the Panama Canal. It is covered in tropical rainforests, and its inhabitants have been studied extensively. It would be a mistake to look at a forest as only ground habitat. The canopy supports a tremendous abundance of life, particularly arthropods. These critters are particularly tasty to predators and must find a way to escape within their decidedly hazardous habitat that is located over 90 feet (30 meters) off the ground. Falling is a bit of a risk. But what if you do fall? You could land in the understory or on the ground which, if it doesn’t kill you, is both unfamiliar and full of predators. To avoid this potentially lethal scenario, many wingless arthropods have developed the ability to orient their bodies (via visual cues, appendages, and other structures) such that they are more likely to fall towards tree trunks.

The genus Selenops is a large and common group of nocturnal spiders. They are easy to find and collect, often hiding under bark or in crevices. The researchers went out into the forests and collected a bunch of these spiders. The spiders were then weighed and photographed. The images were then analyzed for the horizontally projected areas of different segments and appendages. Then these data were put together to give “effective wing loading.” Here’s where we get to the fun part. The spiders were put into individual plastic cups and taken up into the canopy. The cups were held at a known distance from a tree trunk, inverted and tapped to release the spider. Geronimo! These drop tests were filmed at 60 frames per second so that glide index (ratio of horizontal distance from the tree trunk to the total distance traveled) could be calculated. The videos also allowed for the measurement of how the legs were being used to maneuver. The spiders were also scored in terms of their performance, either directly reaching the tree, indirectly or irregularly gliding towards the trunk, or failing completely and landing elsewhere.



Most of the spiders had a successful, directed decent without the aid of draglines or balloons. They fall several meters and then glide to a trunk. During this fall, they were observed to adopt body postures that orient their bodies to descend head first with the forelegs out to the side and slightly forward and the rest of the legs out and back. This foreleg asymmetry was shown to significantly change body heading meaning that they are using their legs to control their glide trajectory. Also, glide index was shown to decrease with increasing body mass. They hypothesize that this negative relationship means that larger spiders must accelerate under gravity to airspeeds where aerodynamic lift becomes significant relative to body weight.

This is an interesting result because other arachnids do not show it. These spiders have developed the ability to control their glide trajectory. This means that they have evolved novel mechanisms of body righting and maneuvering. Gliding spiders….cool.


Stephen P. Yanoviak, Yonatan Munk, & Robert Dudley (2015). Arachnid aloft: directed aerial descent in neotropical canopy spiders J. R. Soc. Interface, 12 : 10.1098/rsif.2015.0534

(image via Toy Story screencap)

Vampire Plants: Sucking Life into the Community

I would like to introduce you to the yellow rattle (Rhinanthus minor). This little plant has pretty yellow flowers that belie a dark secret: it is a vampire plant. Okay, technically, it is a hemiparasite. The yellow rattle has green, photosynthetic leaves to make its own food, but its roots latch onto those of nearby plants to steal their water and nutrients. See? Vampire. I guess you could say that it hasn’t gone full parasite. So what’s wrong with a little leaching of material from your neighbor? Must be like stealing cable, right? Well, not exactly. Hemiparastitic plants can have impacts that are highly disproportionate to their small size. By stealing water and nutrients, they reduce the host plants’ photosynthetic rate and biomass, making them less competitive in their habitat. When you are less competitive in a highly-competitive environment then you don’t last all that long. But this is looking at it on an individual, plant-by-plant, level. Let’s scale it up a bit.

We’ll start by following the logic trail. Hemiparastic plants are widespread in ecosystems such as meadows where they attach to dominant grasses (in this case, dominant meaning numbers). As individual grass plants are weakened or killed, overall grass biomass decreases. When the dominants are gone there is more room for other types of plants to move in, increasing species richness. More types of plants attract more primary consumers (like insects) to feed on them. More insects attract more secondary consumers, and on and on. All in all that one little plant has caused indirect community level changes. A new paper by Hartley et al. in Ecology looks at how this one little plant can affect multiple trophic levels (or levels in the food chain).

The researchers laid out 13 blocks, each containing four 1 by 1 meter plots, in a field site in Sussex, UK. Three out of those four plots were allowed to be naturally colonized by yellow rattle. These “infected plots” were then randomly assigned to one of three treatments: yellow rattle removed, present, or enhanced. Then, during maximum vegetation and invertebrate abundance, plots were censused. Counts, ground cover, vegetation height, and species richness were measured for plants. Invertebrates were sampled with a Vortis suction sampler (a.k.a. bug vacuum) and hand counts. They were identified and classified into their trophic levels: herbivore, predator and detritivore.

They found that the density of yellow rattle had pronounced effects on the plant community. Grass cover was lower, plant diversity higher (although not richness), and plant height lower in plots where the hemiparasite was present or enhanced. Going up a trophic level, sap-feeding insects (Hemiptera) increased by 130%, caterpillars (Lepidoptera) by 217% and weevils (Curculionidae) by 188%. Whoa! Going up another level to the predators, spiders and harvestmen (Araneae and Opiliones) increased by 142% and bees and wasps (Hymenoptera) by 180%. Continuing with the whoa! Going down to the detritivore groups, wood lice (Isopoda) went up by 116% and springtails (Arthropleona) by 58%. Of course, not all animals fit into a single trophic group, but as you probably guessed by the trend you’ve been seeing, those groups went up too. Slugs and snails (Gastropoda) by 103% and mites (Acari) by 57%. That’s quite a list, but not everything increased. There were some non-significant groups including flies (Diptera), rove beetles (Staphylinidae), and springtails (Neelipleona and Symphypleona). It is also important to note that these numbers are from enhanced compared to removed plots. The present plots had increases in many of the same categories, though not as dramatic.

In scientist-speak these results showed that “the manipulation of a single sub-dominant plant species causes substantial changes in the abundance and diversity of organisms across four trophic levels in individual plots in a complex grassland community.” Basically, they demonstrated that grasses went down and just about everything else went up just by the addition of one, small and less numerous hemiparasite. This one little plant species caused striking (their term), rapid changes in the community. The less obvious effects of yellow rattle were how the effect was actually occurring. Was it on plant community composition or plant quality or stand height? The authors cite a greenhouse study that showed insects to prefer parasitized to unparasitized grasses when given the choice. Add to that that it is known that parasitic plants impact nutrient cycling, especially enhancing the nitrogen content of vegetation overall. This suggests that it may be plant quality that is the driving mechanism. So the observed, large increase of sap-sucking invertebrates, particularly the Hemiptera, with altered plant quality makes sense as does the increase in detritivores with newly nutrient-rich litter. At this point, perhaps you have considered the impact of these plant-attacking invertebrates as well. Good on you. They are probably themselves doing some damage on and affecting change on the plant community, but this work doesn’t go into that. Time for another study I think!


Hartley, S., Green, J., Massey, F., Press, M., Stewart, A., & John, E. (2015). Hemiparasitic plant impacts animal and plant communities across four trophic levels Ecology DOI: 10.1890/14-1244.1



(image via Urban Butterfly Garden UK)

Not So Simple: Social Evolution in Silk-Weaving Ants

Silk weaving ants. That in and of itself is really neat. Then you see this picture of Polyrhachis shattuck...I mean, look at her! How many cool points can one animal rack up? A new study in Behavioral Ecology and Sociobiology takes a look at these arboreal nesting and silk-weaving ants.

Let's begin with sociality. It is one of those subjects in biology that is considered its own discipline. When you think of social animals you probably think of herds of mammals or maybe schools of fish. Sociality reaches its peak in eusociality, a surprisingly complex and truly social organization. These animals live in groups, cooperatively care for juveniles, divide labor, and overlap in generations. Studies of these social systems has shed light onto broader concepts of collective decision making, even leading to advances in our own technology (traffic flow, communications networks, internet searches, etc.). However, as much as we know about the social mechanics, we know very little about the evolution of such systems.

Most eusocial animals are found in the phylum Arthropoda, with the order Hymenoptera being the largest and most well-known, and all ants classified as eusocial species. And ants are the focus of today's chosen study. Ant larvae spin individual protective cocoons of silk and, depending on the species, that silk is either allocated to the colony or sequestered for the larvae’s individual needs. Donated silk is used by the worker caste to weave together leaves into nests. The “lowest grade” of arboreal (a.k.a. tree-dwelling) ants, Dendromyrmex, have larvae that produce silk without any interaction or provocation from the worker ants. In “intermediate grade” ants, Camponotus senex and Polyrhachis ?doddi (re-described as Polyrhachis robsoni (Kohout 2006)), the workers hold larvae at the work site and, with simple ritualized behaviors, the workers collect the silk. In the “highest grade” genus, Oecophylla, the larvae donate their silk supply to the colony. A worker ant will use highly ritualized behaviors - bring the larvae to the work site, straddle a leaf seam, use antennae to tap the head of the larva (telling it to extrudes silk from its salivary glands), use silk to glue together the seam, repeat.

A comparison of ant genera in this way, simple to complex, is thought to represent possible evolutionary steps in nest-weaving behavior. However, molecular sequence data suggests that nest-weaving has evolved independently in each of the four genera in which it occurs. This new study focuses on Polyrhachis ants. This genus offers good within-taxa comparison of multiple life strategies as different species vary in their nesting locations, from intertidal to subterranean to arboreal, the presence of nest construction, and even silk sources.

A total of 37 specimens of ants from all 13 currently recognized (*grr*, an often frustrating term in insect taxonomy) subspecies and five outgroup taxa were used for this study. The researchers isolated total genomic DNA and amplified and sequenced DNA from six fragments using specific primers for each gene region. After they collected the sequences, they analyzed and aligned them using computer programs. In their complicated analysis (they used Bayesian…that always makes my eyes cross) they input the gene level data along with variables of nesting preference (ground = soil, logs, stones vs. arboreal = twigs or leaves in trees) and nest construction (silk weaving vs. no silk vs. other silk). All of this allowed them to construct phylogenies (like an evolutionary family tree) and infer relationships among the species and ancestral states for behavior.

Their results showed robust phylogeny with strong support for the monophyly of the genus Polyrhachis, further supported by the inclusions of nesting preference and nest construction.This is good because it provides a nice, solid ancestral reconstruction for the evolution of the different species and their relationships to each other. It also allows for the comparison of the different nesting strategies within the framework of evolution. The investigation turned up some very interesting results. Simply, their results do not support the stepwise evolution of simple to complex. They found that the production of arboreal silk nests is the ancestral state with at least two transitions to subterranean nesting and the loss of silk weaving as species become more derived. There is also some flexibility and reversal in the behavior. Basically, the ants evolve, abandon and then re-evolve the nest weaving practices. The loss of silk nest weaving seems to occur with the transition from arboreal to terrestrial nesting followed by the re-evolution of silk nest weaving. This suggests a strong but flexible link between nesting preference and nest construction.

To illustrate this evolve-abandon-re-evolve point, the researchers present the example of Hedomyrma, a subgenus within a larger clade of subterranean nesters. This larger clade has already lost both arborality and nest weaving. But there are 2 species of Hedomyrma (Polyrhachis argentosa and Polyrhachis fervens) that have reverted to arborality. The re-evolution of this nesting preference has come with the modification of building nests within the hollow internodes of bamboo sans silk. Another reversal pattern is seen in a third species of Hedomyrma (Polyrhachis turneri), which has larvae that retain all of their silk for their own cocoon-constructing needs. Rather, worker ants steal silk from spiders to build nests on the sides of rocks. So the nest construction characteristic is what has re-evolved, just with a different mechanism. Larval cocoons have been lost in 2 of the arboreal nest-weaving species studied, and the allocation of larval silk to colony rather than individual need is considered a more derived but decoupled characteristic of nest construction.

I think that both the flexibility and the rapid evolution (or re-evolution) of this system is what attracted me to this paper. We know that evolution is a complex concept that we often boil down to from-simple-to-complex, and in many cases it is exactly that. This study almost reads like a sequel, a what-happens-next sort of thing.


Robson, S., Kohout, R., Beckenbach, A., & Moreau, C. (2015). Evolutionary transitions of complex labile traits: Silk weaving and arboreal nesting in Polyrhachis ants Behavioral Ecology and Sociobiology DOI: 10.1007/s00265-014-1857-x


(image of Polyrhachis shattuck, Maliau Basin, Sabah via AntWiki via California Academy of Science Ant Course)

Small Things, Big Problem: Microplastics Uptake in Shore Crabs

Lately I've been gearing up for some nano-particle research, and so I've been doing a lot of reading about very small things. While perusing the literature, I came across a paper published online in Environmental Science and Technology that takes a look at microplastics.

Let’s start with the Great Pacific Garbage Patch, a very good example of this type of marine pollution. This huge collection of marine debris in the North Pacific Ocean is created by an ocean gyre, a stable circular ocean current that draws in debris where it is trapped and builds up. The collected debris is our litter – plastics and other material that are not biodegradable. They can’t escape the gyre, they just collect. And as they sit out there swirling around, they break down into smaller and smaller pieces called microplastics.

Microplastics are defined as those plastic particles less than 5 mm in length, and these small particles are a huge marine pollution problem. They are classified into two groups: (1) primary microplastics that are created at the microscale for use in products like cosmetics and drugs and (2) secondary microplastics that are products of the breakdown of larger items. As a whole, they are persistent and widespread – we’re talking worldwide, the Great Pacific Garbage Patch is just the most well-known aggregation. These microplastics are very abundant, we’re talking 1,000-100,000 particles per cubic meter of seawater! And there is growing evidence of the danger these tiny materials are having on marine life, everything from turtles to sea birds to fish and even zooplankton.

A new study by Watts et al. takes look at the uptake of these microplastics in the shore crab (Carcinus maenas). Previous studies have shown that an important prey species of the shore crab, the common mussel (Mytilus edulis), accumulates microplastics as it filters the water for food (“ventilation”). In laboratory conditions, the direct transfer of microplastics from mussels to crabs has been shown, but then again, it has also been shown that crabs uptake microplastics as they pull water through their gills. So what exactly is going on here? How are these crabs exposed and are they able to clear the microplastics from their bodies?

This is one of those studies where I just love to describe the methods. The first thing the researchers had to do was to assess the ability of the crabs to uptake microplastics (in the form of 8-10 um polystyrene microspheres) through their gills. To do this, they fitted the crabs with masks designed to allow measurements of ventilation. Yep, they put little masks on crabs. Picture that. I love science. Next they assessed the ability of the crab to take up microspheres in their food by exposing mussels and then turning them into “jellified mussel homogenate” to then feed to the crabs. I wonder which undergrad had the lovely job of making gelatin mussel popsicles? To see if the microplastcs were cleared, they let the crabs sit in their tanks and tested the abundance of microspheres in the water during water changes every 2 days for 22 days, sampling periodically. During each stage of the experiment, they measured the abundance of microspheres in the gut and gill tissues, fecal material, and hemolymph (like blood). Using fluorescent microscopy and Coherent Raman scattering microscopy (CRS; a multiphoton microscopy that produces label-free contrast of both the target sample and the surrounding biological matrix), they were able to look at the location of the microplastics within the tissues.

The researchers found that the masked crabs took up 31,000-62,000 microspheres (0.39-7.7% of the initial exposure concentration) into their gills after only 16 hours. But this uptake was not even across the gills, with greater uptake in the posterior gills. The crabs where able to expel some of the spheres, but slowly, still expiring microspheres 21 days after being exposed. Imaging the gills showed the microspheres to be associated with the gill epidermis. The feeding experiment showed all crabs to have microspheres in their foregut and later in their fecal material. The residence time of these microspheres was short, but still took longer to excrete than regular food waste, up to 14 days. Microscopy showed microspheres associated with the internal setae of the foregut lining. But, neither the ventilation experiment nor the feeding experiment showed any microspheres in the hemolymph.

Back to the question of what’s going on here? The shore crabs did take up microplastics in both types of exposure, but residence time is the key. They were able to clear the microplastics they got through dietary means, but they were still trying to clear microplastics they took up during ventilation almost a month later. The authors constructed a model to explain the mechanism of the movement of the microplastics. They found that the crabs tended to exhibit an asymmetry in microplastic uptake in the gills, which they attributed to the pumping mechanism of the scaphognathite being more dominant on one side of the gill chamber. Also, the posterior gills have a larger surface area than the anterior gills so they are more likely to take up microplastics into their lamellae. The crabs were unable to dislodge the tiny particles by normal gill cleaning actions. It is interesting that no microspheres were found in the hemolymph at any of the sampling points in either experiment. That suggests that there is no movement of the particles. It is likely that the particle size they used (10 um) was a little bit too large as it has been shown that sizes of 0.5 um are able to translocate in these crabs. This idea of particle size is something I’ve been seeing with increasing frequency within the nano-particle literature, along with polymer type, shape, and coatings. To that I would add that species is probably also in the mix as gills in crabs and fish are structured differently, and nano-particles have been shown to move in to organs like the liver in fish.

Studies like this are interesting because they show how very small things can become a very large problem affecting multiple tissues of the same organism up to multiple levels of a trophic cascade. I mean, think about it, even we humans could be affected. After all, we consume a lot of crab. How many microplastics are you ingesting when you stop at the crab shack for a quick lunch?


Watts AJ, Lewis C, Goodhead RM, Beckett SJ, Moger J, Tyler CR, & Galloway TS (2014). Uptake and Retention of Microplastics by the Shore Crab Carcinus maenas. Environmental science & technology PMID: 24972075


I know I used some technical terms, if you need some help with crustacean anatomy check out Invertebrate Anatomy OnLine.

(image via UGA Evolution 3000H)

The Charge of the Crazy Ant: Chemical Warfare Between Invading Species

LeBrun, Jones, and Gilbert (2014) Figure 1A

I’ll be the first to admit that I've been a little blog-negligent lately. Even when all of the ice and snow we've gotten here on the East Coast forced me to stay inside I just binge watched shows on Netflix instead. I’m not sure what brought me out of my procrastination funk and compelled me to do a little reading and writing. If you've been following the Facebook page then you've been getting a lot of yummy sciency tidbits, but it’s time for me to get back on the hard science wagon. I think I’ll start off with a great couple of papers about ant chemical warfare.

These papers focus on invasive ants, a big problem in many regions. To really grasp one of the underlying aspects of their warfare strategies, you must first understand the basics of an invasive species. Start by recognizing the difference between a native species and an exotic species. Put simply, a native species occurs naturally (or natively) to a habitat and an exotic species does not. Exotics can come in any biological form, but they are not necessarily a problem to their new habitat (think: earthworms). It’s when an exotic species becomes an invasive species that there is a problem because invasives cause environmental, economic, and/or human health harms. The reason for this is that they did not evolve together with the ecosystem in which they find themselves. There are no checks and balances in place to curb their population growth, things like predators, parasites, and competitors. Their unnaturally large population numbers then become harmful to the native species that suddenly have to deal with and compete against them, dramatically altering the community and habitat.

It is often the case that multiple species invade a region. Throughout the rest of this post I’ll be discussing new papers by Michael Kaspari and Michael Weiser and by LeBrun, Jones, and Gilbert (specifically at the latter) that take a look at just such a case in ants. The red imported fire ant (Solenopsis invicta) first came to the United States from South America around 1930. This species is far more aggressive than your typical American ant, not only in how they like the bite the hell out you (that’s a lot of personal experience talking) but also in their predatory abilities and landscape re-engineering. Now enter the tawny crazy ant (Nylanderia fulva). This new exotic invasive species was transported to the southeastern U.S. in the early 1980s and has begun to spread.. These two species have common source assemblages, their native ranges overlapping in northern Argentina, Paraguay, and southern Brazil. Until the introduction of crazy ants, the fire ant has enjoyed an uninterrupted domination of the native grassland ant assemblages. But now that the crazy ant has arrived on the scene they are displacing the fire ants. Why is this?

Since the fire and crazy ants have overlapping native habitats, they have evolved to compete directly for resources. The tawny crazy ant easily expels the fire ant from any food items it controls, up to 93 percent of the time. Also, tawny crazy ants have often been found living inside fire ant mounts, having usurped the mound and evicted the owners. Fire ants are strong and resilient and so the crazy ants must have a strong competitive advantage.

Now, finally, we get to the meat of the post: chemical warfare. If you've been stung by a fire ant (or ants, plural, as is usually the case) then you know that they pack a wallop! They have an alkaloid venom called Solenopsin that to humans causes a painful, fiery sting, and to other ants acts as a topical insecticide. The crazy ants do not have stingers but instead possess an acidopore (a specialized exocrine gland) on the end of the abdomen that sprays their venom into a mist of formic acid. They will charge into masses of fire ants misting as they go. But the fire ants don’t just stand by idly to be sprayed with venom and die, they fight back. The fire ants “gaster flag,” extruding venom from their stingers and dabbing it onto a nearby attacking ant. Normally this would result in the death of said ant. However, LeBrun and his colleagues have observed what they are calling a “detoxifying behavior” in the attacking tawny crazy ants. In this behavior, an afflicted ant stands on its hind legs, run its front legs through its mandibles, and grooms itself vigorously, periodically reapplying its acidopore to its mandibles (check out the video!).

To test this behavior the researchers conducted a series of experiments to see if there is really a detoxifying component, to see where it is coming from, and to evaluate the species-level specificity of the behavior. For the first they staged antagonistic interactions between the two species, sealing a portion of the crazy ant acidopores, and then observing afflicted individuals for behavior and survivorship. They found that those tawny crazy ants that had had their acidopores sealed had a low survival rate (only 48 percent). However, those with working acidophores had a 98 percent survival rate, supporting the detoxifying hypothesis. The Dufour’s and venom glands (exocrine glands used for communication and defense) both duct to the acidopore in this species. To see where the detoxifying agent was coming from they applied solutions of fire ant venom and tawny crazy ant glandular products to Argentine ants (Linepithema humile), which are morphologically similar to crazy ants but do not have the detoxifying capability. These tests showed the venom gland of the crazy ant to contain the detoxifying agent. When the crazy ant’s formic acid was tested it was found to be the compound responsible for detoxifying fire ant venom.

The production and application of this antidote is a potentially costly endeavor for the crazy ants. Yes, it is the difference between life and death, but when to apply it must be considered. Why use a costly resource if you don’t have to? The authors conducted a series of ant interaction tests where they had crazy ants interact independently with eight Texas ant species including fire ants, observing when the crazy ants chose to apply their detoxifier. They found that after chemical conflict with fire ants, crazy ants detoxified themselves with almost 7 times more frequently than the average response to other ant species. This suggests that this detoxifying behavior is specifically adapted to competition with fire ants, and it is probably a key factor in the displacement of invasive fire ants now underway in the southern United States.


LeBrun, E., Jones, N., & Gilbert, L. (2014). Chemical Warfare Among Invaders: A Detoxification Interaction Facilitates an Ant Invasion Science, 343 (6174), 1014-1017 DOI: 10.1126/science.1245833


Kaspari, M., & Weiser, M. (2014). Meet the New Boss, Same as the Old Boss Science, 343 (6174), 974-975 DOI: 10.1126/science.1251272


U.S. Fish and Wildlife Service's page on Invasive Species
The University of Texas at Austin Fire Ant Project
Texas A&M AgriLife Research Extension page on Tawny Crazy Ants

Pinpointing the Pollen: Honeybees and a Host Jumping Virus

Lately I've been revisiting some of my past topics and continuing the story with new research. Such is the case today. A relatively popular post of mine from 2010 called The Buzz on the Bees described a study from that year by Jerry Bromenshenk et al. investigating Colony Collapse Disorder (CCD). CCD describes the mysterious, sudden and serious die-off seen honeybee (Apis mellifera) colonies across the U.S. It is characterized by sudden colony death with a lack of adult bees in front of the die-outs. Honey stores and recent brood rearing are often evidenced, and sometimes the queen and a small number of survivor bees remain. The 2010 study found CCD colonies to contain an iridescent virus (IIV) (Iridoviridae; a DNA virus) that tracks with the microsporidia, Nosema apis and N. ceranae (specifically the latter), when compared to healthy colonies. This and previous scientific studies, using sensitive genome-based and proteomic methods, have also found small RNA bee viruses. These RNA viruses, alone or in conjunction with other pathogens, have frequently been implicated in CCD.

A new study published a couple of days ago in mBio by Ji Lian Li et al. correspondingly takes a look at the role of viruses in CCD. Evidence from previous studies shows that viruses that cause common infections in honeybees also infect other hymenopteran pollinators. A study published by Singh et al. (2010) even showed these viruses to be present and infective in pollen pellets.

I’ll conjecture that if you ask most people you’ll find that they don’t really think of plants as capable of getting viruses. That is until some disease comes and kills all of the fruit trees in their back yards. But plant viruses are like other viruses, obligate intracellular parasites, and they require a way to transmit from one plant to another. As you may have noticed, plants don’t generally get up and move around. This means that their viruses need a vector. Generally, these vectors are herbivorous insects. These insects are carriers, usually by carrying around infected pollen spreading the virus from one plant to another without themselves getting sick. To date, only a few plant viruses are known to also affect their insect vectors.

Li et al.’s new study takes a closer look at the role of pollen in virus transmission in honeybees. Initially, they carried out a study to screen bees and pollen loads of bee colonies for the presence of frequent and rare viruses. This resulted in the chance detection of a plant virus, tobacco ringspot virus (TRSV). This virus is a type species of the genus Nepovirus within the family Secoviridae, and it is known to infect a wide range of herbaceous crops and woody plants. Like other members of this genus, TRSV has a bipartite genome of positive-sense, single-stranded polyadenylated RNA molecules, RNA-1 and RNA-2, encapsidated in separate virions of similar size. For you non-biologists, this basically means that the virus has two genome segments/virus particles and can be directly translated into the desired viral proteins by the host cell. RNA viruses typically mutate very fast and are really good at working around host defenses (HIV and hepatitis are good examples of RNA viruses).

It is known that honeybees transmit TRSV from infected plants to healthy ones, but its presence in the researchers' screens got them to wondering if this plant virus could cause systemic infection in the exposed honeybees. To answer this, they collected adult worker bees, samples of the pollen being processed by a colony, and the ectoparasitic mite Varroa destructor (great name!) within the hive. They assessed 10 colonies for 1 year, classifying them as strong or weak based on the size of adult populations, amount of sealed brood, and presence of food stores. From their samples they purified virus particles from the adult bees and used them for cDNA library construction, virus-specific primer design, total RNA extraction, conventional RT-PCR, in situ hybridization, cDNA sequencing, and a phylogenetic analysis.

The observations of the colonies revealed an increase in bee deaths starting in the autumn and peaking in the winter. The researchers found both TRSV and IAPV (Israeli acute paralysis virus, common in honeybees) to be absent in colonies classified as strong, but both were found in weak colonies. Weak colonies too were found to have more multiple virus infections. These weak colonies were the ones less likely to survive through the cold winter months. Additionally, TRSV of the same strain was detected in the mites of infected colonies suggesting they obtain it from their bee hosts.

These results are the first evidence that honeybees exposed to virus-contaminated pollen can also be infected and that the infection can be systemic and spread throughout their entire body. Any host jumping is not without its challenges. In order for a virus to jump to a new host it must have the opportunity to come into contact with a perspective host, undergo genetic changes so that it may enter a new type of host cell, and gain the ability to spread horizontally between individuals within the new host populations. It seems that TRSV has been successful in overcoming all of these challenges. Its presence in the mites suggests that they could be a vector for the horizontal transmission between colonies. However, food-borne transmission (via pollen) is the most important route for transmission. Their results suggest that TRSV is neurotropic (affecting the nerves) in the honeybees, potentially causing severe functional impairment of nerves and muscles.

Do these results definitively conclude that TRSV is the cause of CCD? Well, no. But this study does add to a growing body of evidence that implicate parasites and pathogens as the key culprits.


Ji Lian Lia, et al. (2014). Systemic Spread and Propagation of a Plant-Pathogenic Virus in European Honeybees, Apis mellifera mBio, 5 (1) DOI: 10.1128/mBio.00898-13


NY Times article: "Bee Deaths May Stem From Virus, Study Says"

Also, check out these links for more information on Colony Collapse Disorder:
Mid-Atlantic Apiculture Research and Extension Consortium (MAAREC)
United States Department of Agriculture: Agricultural Resource Service
United States Department of Agriculture: National Agricultural Library
The Ohio State University's Agriculture Network Information Center's Bees and Pollination Page


(image via Wikipedia)

Unraveling Spider Silk

An interesting infographic about spider silk.

(via The Guardian)

They're All Alike: The Giant Squid Conundrum

I wasn’t going to post on another paper this week but then two things happened: I saw the video of the first giant squid filmed in its natural habitat (those scientists get so excited!), and I saw the study about giant squid diversity. I posted the first above and now we'll take a look at the second.

The giant squid (Architeuthis spp.) is one of the largest invertebrates and lives in the deep sea. It was first described as Architeuthis dux in 1857 by Danish naturalist Japetus Steenstrub, but since then, as many as 21 nominal species of Architeuthis have been described. The descriptions of this creature have primarily come from remains found washed up on beaches, found floating on the ocean surface, caught by deep-sea trawling activity, or in the stomachs of sperm whales (Physeter macrocephalus). It wasn’t until 2004 that a live specimen was observed in its natural habitat, and earlier this year that the first video footage was published (although not the in-the-natural-habitat version above). It is estimated that female squid reach a total length of 18m (59ft) and males reach slightly smaller sizes. The giant squid is globally distributed, with the exception of polar regions. They feed primarily on fish and smaller cephalopods. Studies of carbon and nitrogen isotope profiles of the upper beaks suggest ontogenetic diet shift earlier in life (smaller to larger prey items), and carbon isotope composition remains constant in food sources indicating that the squid inhabit relatively small, well-defined and productive areas. The predation of adult squid by sperm whales suggests that squid population size must be large enough to support such a large whale population, although this has never been proven.

There are some rather obvious difficulties in studying giant squid using conventional, observational techniques. So other techniques must be utilized. Enter, DNA. Recent advances in DNA sequencing techniques have made it easier, quicker, and more economical to sequence long stretches of DNA. The role of DNA sequencing is becoming more and more important in phylogenetic and population biology studies. It allows you to assess the number of species, examine the amount of genetic variation, and describe population structure.

In a new paper in the Proceedings of the Royal Society B: Biological Sciences, researchers collected 43 Architeuthis soft tissue samples from the carcasses of dead animals across their known range. They extracted DNA samples from the specimens to analyze the mitochondrial genomes (mitogenomes) and levels of nucleotide variation. They generated mitogeome datasets using several strategies, depending on the quality of the DNA in each sample. I’m not going to go into their sequencing methods – if you are a molecular biologist then you already know them, and if you aren’t then I’ll just bore you. To look at the population level of the genetic variance, they wanted to compare their samples with the fossil record of coleoid cephalopods. This is challenging considering the extremely limited fossil record for these organisms. So they used four different mutation rates to tentatively estimate a time of expansion and upper and lower bounds for the time of divergence of Achiteuthis from other squid families.

They were able to complete 37 complete and 6 partial mitogenome sequences. Remember up at the top of the post where I said “21 nominal species of Architeuthis have been described?” One pretty strong conclusion of this study is that there is only one species of Architeuthis that exists, namely Architeuthis dux (Steenstrub, 1857). The researchers found the haplotype diversity of these giant squid to be high at the mitogenome level, but the level of nucleotide diversity in these sequences was found to be extremely low, with only 181 segregating sites of a 20,331 base pair long sequence. Only the basking shark (Cetorhinus maximus) has a similarly low diversity, which is the result of a recent bottleneck. This diversity for giant squid is much lower than is seen in other squid, 44 times lower than Humboldt squid (Dosidicus gigas) and 7 times lower than the recently restricted population of oval squid (Sepioteuthis lessoniana). The high haplotype to low nucleotide diversity relationship is interesting because it shows that out of a very diverse phyla of animals, the giant squid is the odd one out. Looking at the species across its range, there was no evidence of any phylogeographic structure, which is odd considering the global distribution.

So how do you explain the low genetic diversity in comparison to the global distribution (and potentially large population size)? The authors hypothesize that it could be a low rate of mitochondrial DNA evolution, something that has been observed in other marine organisms. But a low mutation rate does not explain why mitogenome duplications maintain near 100 percent identity. The authors suggest that “perhaps the duplicated sequences form stable secondary structures, which are somehow selectively beneficial, thereby causing mutations to be under negative selection,” which would lead to “a decreased rate of divergence in the duplicated regions relative to the rest of the genome, which does not appear to be the case.” Alternatively, it could be a recent selective sweep such as a bottleneck. Bottlenecks are events that greatly reduce the size of a population, usually resulting in a large reduction in the genetic diversity of that group. If this bottleneck were followed by an expansion in the number of individuals in that population then you would see that low diversity spread amongst a large population. Modeling and analysis of data support the latter hypothesis over the former.

Unfortunately, genetic data alone can’t provide an answer as to why this might have happened. Whatever event it was, climatic or biological, it would have had to been wide ranging enough to affect a global population. Perhaps it was a sudden inflation of a population that was historically smaller. It is known that cephalopods tend to be subdominant predators, and as such, are affected by the changes in population of predators and competitors. If this small size was due to restraints on predators and/or competition and that restraint were released then you would expect such an inflation in squid numbers. Considering the effect of industrialized whaling in the 1700s to late 1800s, this is a likely explanation, but still too recent to explain it entirely. This change in predators and/or competitors could have been the result of climatic effects such as the last ice age changing. Such changes could have altered the abundance and distribution of competitors such as predatory fish. Or perhaps, rather than a bottleneck, A. dux existed historically as a single, small, geographically isolated population that then expanded globally. This expansion would have had to been in a non-ordered fashion with either nomadic adults or dispersing juveniles and small pelagic paralarvae capable of using currents to travel long distances. But if they can disperse really far then why would they have been restricted historically? The authors hypothesize that a global population existed for a considerable time, and that an average of just one individual exchanged between two populations per generation will be enough to prevent genetic differentiation between them. They believe that the wide ranging dispersal of paralarvae and juveniles on the currents of the upper layers of the oceans could achieve this. These young life stages float along with the currents feeding on zooplankton and such until they reach a sufficiently large size, after which they descend to the closest nutrient-rich deep habitat where they remain until maturation.

I think that’s a pretty good explanation. What about you?


Winkelmann, I., Campos, P., Strugnell, J., Cherel, Y., Smith, P., Kubodera, T., Allcock, L., Kampmann, M., Schroeder, H., Guerra, A., Norman, M., Finn, J., Ingrao, D., Clarke, M., & Gilbert, M. (2013). Mitochondrial genome diversity and population structure of the giant squid Architeuthis: genetics sheds new light on one of the most enigmatic marine species Proceedings of the Royal Society B: Biological Sciences, 280 (1759), 20130273-20130273 DOI: 10.1098/rspb.2013.0273


ScienceNOW article: "Giant Squid Worldwide Are One Species"
ScienceDump: "The search for the giant squid"
Vido via Nature's: "Giant squid filmed in its natural environment"

Dung Beetles and Ball-Rolling: Star Light, Star Bright

Lately, it seems that poo is a popular topic in science news sections, and the dung beetle seems to be up front and center. I suppose that, if you are a dung beetle, you've solved all sorts of poo-related problems. If you recall the dung beetles and ball-cooling post from November, you will remember that these insects use their dung balls to help cool off their feet on the blazing hot African sands. But what if you are a beetle that works at night? You can chuck out the hot feet problem and worry about a whole new one: navigation. A new paper published in Current Biology suggests how dung beetles may solve this navigation dilemma.

For African ball-rolling dung beetles (Scarabaeus satyrus), the best ball rolling strategy is the straight line. The straighter the path the beetle uses to roll the ball away from the dung pile the less likely it is their ball will be stolen by rival beetles. They spent all that time to pinch and roll the poo together, it is a waste of time and energy if it is stolen. Competition is fierce near the dung heap, so a quick and straight exit strategy is best. Getting that ball to roll straight isn't simply a matter of putting one tarsus in front of another, it usually involves exploiting such celestial features as the sun and the moon to orientate. However, it has been observed that many beetles will still manage to orientate along straight paths on clear moonless nights. So what are they using to help them navigate?

To answer this question, a group of researchers set up some beetles in arenas. I know, it already sounds good. On a starlit night, they placed dung beetles with their dung balls in a flattened, leveled, and enclosed circular arena.They first wanted to know how accurately the dung beetles could orientate along straight paths when they were prevented from seeing any celestial cues at all. So they made little hats for them. No kidding. They made little caps from small pieces of cardboard and attached them to the beetles' heads so that their dorsal field of view was obscured but their ventral eyes were unimpeded. Then they let them roll, filming them from above so that the rolling paths could be reconstructed and measured. The sight impeded beetles had path lengths almost 4 times longer than beetles that could see the moonless night sky. Okay, so maybe the beetles are using landmarks, like trees, to help them. To test this, the researchers made another arena that removed all visual cues (including the observer), enclosing it with a circular black cloth wall. Because they removed all observer cues, like the camera, they had to design the arena such that it could tell them when the beetles were at the edge without the researchers filming or looking. So they made the arena wall with a slightly larger diameter than the floor so that there was a gap large enough to allow the beetles reaching the edge to fall from the floor into a trough below, resulting in an audible thump sound. Since ball rolling speed is relative to path straightness (the straighter your path the faster you get to the edge), they just had to time the thumps. Clever. Under a full moon, starry night the beetles took 21.4 seconds to exit the arena and on a moonless, starry night they took a reduced, but not significantly so, 40.1 seconds. The story changes when you put the little beetle hats back on. With the caps they take a significantly longer 124.5 seconds (note: this is not significantly different than an overcast night at 117.4 seconds).

Figure 2 from Dacke et al. (2013) showing the effect of stars on dung beetle orientation

Now we know that stars are important in getting a dung beetle to roll its ball straight. Good. But we also know that most stars are too dim for tiny beetle eyes to discriminate. It is probably unlikely that the beetles are picking out constellations for their navigating needs. So what orientation information are they extracting from a starry sky? To answer this question, the researchers grabbed their beetle arena and took it to the Johannesburg planetarium, where they could manipulate the sky the beetles were seeing. Again, clever. They performed the experiments under five different conditions: (1) complete starry sky, with more than 4,000 stars and the Milky Way, (2) Milky Way only, (3) dim stars, with the brightest 18 stars excluded, (4) 18 brightest stars only, or (5) total darkness. They found that the beetles took the same amount of time to exit the arena, irrespective of whether they could see the full projection of the starry sky or only the Milky Way. This means that the dung beetles are using the bright band of light produced by the Milky Way. The Milky Way is a bright band because it is made up of stars, and when the Milky Way part of the projection (a diffuse streak of light) is removed you still see a sky where a higher density of stars defines the galaxy's axis. In this case, the beetles were still able to use the star density but it took them somewhat longer to reach the edge of the arena. It is high density of light forming into the streak across the sky that is visible, and therefore usable, to the beetles.

There is all sorts of navigating going on in the animal kingdom. Now, it appears that we've found another one. One that may be more widespread than we yet know. We just need to go looking.

Dacke, M., Baird, E., Byrne, M., Scholtz, C., & Warrant, E. (2013). Dung Beetles Use the Milky Way for Orientation Current Biology DOI: 10.1016/j.cub.2012.12.034

Some press stories on this paper:
National Geographic: "Dung Beetles Navigate Via the Milky Way, First Known in Animal Kingdom"
ScienceNOW: "Dung Beetles Navigate by the Milky Way"
The Naked Scientists: "Dung Beetles Navigate by the Light of the Milky Way"
The New Yorker: "Dung Beetles, Dancing to the Milky Way"
Wired: "Lowly Dung Beetles Are Insect Astronomers"

(dung beetle hat photo credit to Eric Warrant via the NatGeo link above)

Dung Beetles and Ball-Cooling: The Secret of the Poo

You’re a dung beetle. That isn’t an insult, it’s a visualization aid. You are a dung beetle, you live in South Africa, you roll up feces into balls, you push those balls to a storage location, and you use the balls as food or for brooding. Now, as a human visualizing yourself as a dung beetle, consider the environment you are rolling your dung ball across: the sands of the South African desert. Are your feet hot? How do you cool them down?

The authors of a new paper in Current Biology asked just these questions. The hot desert sands of South Africa can exceed temperatures of 60°C (140°F). Even for the resident dung beetle (Scarabaeus lamarcki) that’s hot. It is known that many species will seek refuges to cool down in these hot climes. For example, desert ants will spend up to 75 percent of their foraging time cooling down on elevated thermal refuges (like stalks of grass). It would make sense that dung beetles, which work under similar hot conditions, would seek refuges as they roll their poo-balls across the sand. Returning to your imagined-dung-beetle-state, what do you do to cool off?

The researchers used infrared thermography and behavioral experiments to see how dung beetles use their dung ball as a mobile thermal refuge onto which they climb to cool down. Jochen Smolka and his colleagues set up two sandy, circular, 3 meter diameter arenas in a natural South African habitat. One of the arenas was shaded in the morning to keep the ground temperature cooler. The other arena was exposed to full sunlight. They found that at the cooler ground temperatures, below 50°C, the beetles roll their dung balls straight across the arena without stopping. On the hotter ground, the beetles were observed to occasionally stop, climb up onto their ball and preen their front legs with their mouth-parts. It is likely that this preening covers the legs in regurgitated liquid, cooling them down by evaporative cooling. After the preening, the beetles perform an orientation dance and continue to roll their balls across the arena.

Fig 1. The dung ball as a mobile thermal refuge. (A) With rising soil temperature, beetles climb onto their dung balls more frequently while rolling (B) Temperature of the right front leg (red) and thorax (blue) of a beetle during its first three ball climbs (periods of rolling are grey) (C) Front leg temperature profile averaged over 84 ball climbs from 7 beetles (D) With silicone ‘boots’ on their legs, beetles perform fewer ball climbs. Similarly, beetles climb onto cool balls less often than hot balls

Ground temperature also significantly affected the frequency of this ball climbing behavior. At progressively high temperatures, the beetles climbed up on their balls more often, spending almost 70 percent of their time on top of their balls when the ground temperature went above 60°C.

So why climb balls? Answer: Ball-cooling. Infrared thermography shows that when the beetles roll their dung balls, the surface temperature of the beetles’ front legs increases by as much as 10°C, but when they climb up on their balls that temperature decreases again. That’s quite a bit, but is it really their hot feet that causes the beetles to ball climb? To this, they applied dental silicone to the beetles’ front legs. Pause: Beetle-booties, fun to say and I’m sure fun to see, and reminds me of the awesomeness that is ants on stilts. They found that these beetle-boots doubled the beetles’ ball rolling time, decreasing their ball climbing by 35 percent. This suggests that the ball climbing behavior is related to ground temperature and the heating up of beetle feet. As it turns out, the poo-balls are acting as thermoregulators in three ways:

1. They are portable, elevated platforms that can be used to escape the hot sand.

2. They are heat sinks. The moist dung ball undergoes evaporative cooling, keeping it the much cooler temperature of 31.8°C. This is substantially cooler than the beetle and the sand.

3. They are sand-coolers. Essentially, they are performing another heat sinking duty, sort of a heat vacuum, if you will. The dung ball draws the heat from the sand so it is cooler for the beetles to walk on.

If the poo-balls are actually acting as heat sinks, both during rolling and while the beetle is on it, then warmer balls should be less efficient heat sinks and the beetles should climb on them more often. The researchers tested this by giving beetles cold balls and hot balls. They found that the beetles climbed the hot balls 73 percent more often than the cold balls, supporting the heat sink hypothesis. “Because beetles roll their ball rather than drag it, the ball, preceding the beetle, cools down the sand the beetle is about to step on” by 1.5°C.

Put together, these mechanisms allow dung beetles to operate during a time of day when most arthropods, and other animals for that matter, seek a cool shelter. I guess there are a lot more good things about poo than I ever realized. And it appears that dung beetles have uncovered the secret of the poo.

Smolka, J., Baird, E., Byrne, M., el Jundi, B., Warrant, E., & Dacke, M. (2012). Dung beetles use their dung ball as a mobile thermal refuge Current Biology, 22 (20) DOI: 10.1016/j.cub.2012.08.057


Here are a few news outlets that have picked up the story:
From Wired UK "Study: Dung beetles cool their heels atop balls of poo"
Discovery News' story "Why Dung Beetles Like to Chill on Poop Balls"
LiveScience's "That's Hot! Beetles Dance on Poop Balls to Keep Cool"
The Naked Scientists' report "Beetles use dung balls to keep cool"

Citizen Science. Get Involved.

Citizen science is becoming more and more popular these days. And why shouldn't it? It is an opportunity for volunteers, who may or may not have specific scientific training, to contribute to ongoing scientific research. The volunteer gets the benefit of participating in a task they are interested in and the scientist gets the benefit of many people going through very large amounts of data, allowing them to accomplish their research objectives. It is just a great way to involve the individual as well as promoting public engagement in science.

Citizen science is not a new concept, it has been around for centuries. However, with advances in technology and the rise of the Internet it has become so much easier to get people involved, especially across large geographic areas. And in most cases the human brain is much better at analyzing images and other data than a computer. Add to that the number of replications you can have when multiple people classify the same image and you can see how errors can be decreased and new discoveries made.

So how does this whole thing work and how can you get involved? Well, first, think about a scientific topic that interests you: ornithology, astronomy, climate change, geology...whatever. The scope of science is so big that there is likely a project that fits your interests. Next, you need to find a project. They come in several varieties. First there is the scope: international, national, regional, or local. Next there is the type of activity you want to do: field work, image or data analysis, or just contributing some of your computer's power. And finally, how long do you want to spend working on this: years, months, or hours. That sounds like a lot but once you have figured these parameters out it will make it much easier to find a projects that suits you. Once you have found a project there is typically a short training session to get you familiar with the user interface and how the data should be analyzed/recorded. Then you are all set to do some science!

I've divided some of the most popular citizen science projects down by category, giving a short description of each. Each icon is linked to take you to the project described. At the end I've linked to a couple of general, easily searchable websites that will help you find the project you want.

ASTRONOMY

This is one of the most popular citizen science fields, and the projects that make up the Zooniverse are the most popular of these projects. There are several projects within the Zooniverse to choose from including:

• Ice Hunters
•  Help find the final target of NASA's New Horizons Mission! After passing Pluto (and pending NASA approval of an extended mission, of course) the spacecraft will retarget itself for an encounter with a Kuiper Belt Object (KBO). The target won't be selected until shortly before the Pluto encounter and there will be lots of images to go through to find out where to go next. This is where you come in. Look at pictures of never seen before objects to find out which one we should visit.
• Moon Zoo
• Explore the surface of the Moon! Look through images taken by NASA's Lunar Reconnaissance Orbiter and answer questions about what you see. Identify craters, boulders (called "Boulder Wars," LOL), or any interesting or weird features you come across.
• Galaxy Zoo: Hubble
•  There are hundreds of thousands of galaxies drawn from NASA's Hubble Space Telescope archive. In this project you get to look at the gorgeous imagery from this telescope and classify the galaxies. Are they elliptical, spiral, irregular? Or is there some new type out there waiting to be discovered?
• Galaxy Zoo: Supernovae
•  This project is similar to the project above, this time contributing data from an automatic survey in California, at the world-famous Palomar Observatory. Except here you are looking for supernovae. Exploding stars!
• Galaxy Zoo: Mergers
• Here you are looking for the merging of galaxies. From images you select simulations that look similar to the targeted merger, tuning your best matches. You can even decide which simulation wins in a series of tournament-style competitions.
• Planet Hunters
• Look for extrasolar planets (planets around other stars)! This project finds planets by identifying how the brightness of a star changes over time.
• The Milky Way Project
• This projects aims to sort and measure our galaxy. Using the beautiful infrared data from the Spitzer Space Telescope you are asked to find and draw bubbles. These bubbles identify the life stages of the stars in our Milky Way Galaxy. 
• Old Weather
• This project works to recover worldwide weather observations made by Royal Navy ships around the time of World War I. This will contribute to climate model projections, improve a database of weather extremes, and track past ship movements and the stories of the people on board.
• Solar Stormwatch
• Help spot explosions on the Sun and track them across space to Earth! Not only will you help to identify and classify activity on the Sun but you will also contribute to early warnings if dangerous solar radiation is heading toward astronauts. 

These scientists are seeking to understand a star that has been a mystery for many years. This star is epsilon Aurigae, it is located in the constellation Auriga, and it is a variable star (it changes in brightness over time). This change in brightness is called eclipse. It takes over 600 days, and it only occurs every 27.1 years. The project scientists will guide you through the process of how to observe epsilon Aurigae, how to send them your observations, and then how to see your results, analyze them, and even publish them in a scientific journal.

SETI@home is a scientific experiment that uses Internet-connected computers in the Search for Extraterrestrial Intelligence (SETI). You can participate by running a free program that downloads and analyzes radio telescope data. It is completely safe. All you need to do is download the program and it will run while your computer is on, not disrupting any of your other computing tasks.

CLIMATE SCIENCE

This project works to produce predictions of the Earth's climate up to 2100 and to test the accuracy of climate models. To do this, they need people around the world to give them time on their computers - time when they have their computers switched on, but are not using them to their full capacity. What do you do? Not much really. You to run a climate model on your computer. It runs automatically in the background, not affecting any other tasks for which you use your computer. It is completely safe and requires no more of your time than it takes to download the program. Read more by clicking the image link or go to download the program HERE.

Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) works to measure and map precipitation. Each time a rain, hail or snow storm crosses your area, you take measurements of precipitation from as many locations as possible and report it on the website. These data are compiled and used to provide accurate high-quality precipitation data, increasing the density of precipitation data available throughout the country, and encourage citizens to have fun participating in meteorological science while heightening their awareness about weather.

This project aims to accurately record and analyze "ice on" and "ice off" events as well as snow depth, air temperature, and wildlife observations to learn how climate change affects our environment. You will receive instructions on how to properly IceWatch (even if you live in a warmer climate), you pick your location to observe over the winter (like a nearby lake, bay, or river), record your observations, and submit them online.



GENETICS AND MOLECULAR BIOLOGY

This project is great for gamers!

Genetic sequences are difficult to understand and decipher their structure, and this project aims to compare them to detect any similar regions they may have. So they have put together a website that abstracts the multiple alignment problem to a game where the goal will be to align words made by pieces of different color instead of letters representing the genetic code (A,C,G,T). You create columns of the same color and create gaps, ultimately finding the best tradeoff between aligning color and creating gaps. You can even choose a puzzle to solve from the disease you want to treat.

Another project that is great for gamers. This project is all about protein folding. Proteins are built from individual amino acids but they don't stay all stretched out in a strand, they fold into very specific shapes. Finding the shapes and the optimal folding is the hard part though and is what this project aims to do. Knowing the structures is important to things like drug development and disease research. The problem has been put into game form. You, as the player, solve a series of puzzles to optimally pack you protein, hide the hydrophobic bits, and clear any clashes. You can play individually or form teams, competing with other protein folders around the world.

OCEANOGRAPHY

The whale shark photo-ID library...its cool just saying it. This project uses photographs of the skin patterning behind the gills of each shark and any scars to distinguish between individual animals. This helps scientists to see where individual animals are going, the abundance of whale sharks, and their distribution. If you see a whale shark while out diving you can report all kinds of information about the encounter by filling out their online form, and you can submit pictures to the library.

Do you love whales? All kinds? This project is working to classify the sounds that whales make into distinct regions. "For example, in Orcas (Killer Whales) there are over 150 identified types of call. Every time you match a pair of Orca calls, you're casting a vote for those two calls to be considered 'similar'." The more this is done the better map the researchers get of calls that are alike. This allows them to identify patterns, groups of whales, and eventually get a better understanding of how whales communicate with each other. All you do is look at a spectrogram and listen to a call and then find a matching call. Simple.

This is a project for reporting jellyfish and other marine organisms. If you have seen jellyfish, red tide, or any other unusual marine life you just go online and fill out their form and submit it. They even have a list of similar projects around the world that you can participate in.

FishWatchers is a project out of the International Game Fish Association. This website allows you to  upload your fish observations and photos through the Internet. Any fish any time. This information will then be used to create current distribution maps to assist in monitoring trends in biodiversity

TERRESTRIAL PLANTS AND ANIMALS

This is a great project from a Dutch entomologist that lets motorists report the date, time, and location of their latest outing and the number of insects that get hit (and probably smushed) by their vehicle. Not only does it give an idea about how many bugs are killed by vehicles it provides insect presence in certain locations and information about their flight patterns.

This is a network of people across the United States who monitor plants as the seasons change. It is a national field campaign designed to engage the public in the collection of important ecological data based on the timing of leafing, flowering, and fruiting of plants (plant phenophases). You can send in regular observations or just a single report. Everything is usefull. They provide good identification keys and other tools you will need to start. Not in the U.S.? I'm sure there is is similar project near you.

This is a U.S. based citizen science project that is a national animal and plant phenology observation program. You find out the plants and animals near you on a provided list, learn to select a site and observe and record what is there, and submit your results.

 eBird is a real-time, online checklist program that reports and accesses information about birds. It provides information on bird abundance and distribution at a variety of spatial and temporal scales. It is amassing one of the largest and fastest growing biodiversity data resources in existence. You enter when, where, and how you went birding, fill out a checklist of all the birds seen and heard during the outing, and submit your observations into the eBird database. They even provide tools so you can maintain your personal bird records and even visualize your personal data with interactive maps, graphs, and bar charts.

Neighborhood Nestwatch is a project out of the Smithsonian National Zoological Park and the Smithsonian Migratory Bird Center. The idea is to find and monitor bird nests so scientists can compare how successful nests are in urban, suburban, and rural areas. All you have to do is keep a watchful eye out throughout the year and report your results.

 I know several people that participate in the Christmas Bird Count each year and have a really great time. From December 14 - January 5 volunteers brave the cold weather to do a little bit of bird counting. Anything from feeder-watching to active birding counts. It provides valuable information on migrating birds, bird abundances and distributions, and much more. There are many groups out there too that participate in the count and would love to have another person to help, regardless of your skillset.

 NestWatch, as you might gather from the name, is a nest-monitoring project. It aims to compile large, continent-wide databases tracking survival and reproductive success of a wide range of species and provide a unified nest-monitoring scheme to track reproductive success for all North American breeding birds. You "get certified" (meaning you learn how to properly observe a nest without jeopardizing the nest), look for active nests, monitor the nests and collect data, and enter the data online. The fact that you get to see baby birds should be a big selling point *wink*

The Backyard Bird Count is similar to the Christmas Bird Count in that it is an annual event that provides a real-time snapshot of where the birds are across the North America. The Count occurs from February 17 - February 20 and takes as little as 15 minutes on one day, or you can count for as long as you like each day of the event. When you are finished you enter your results on their webpage.

When it comes to doing science, watching the visitors to your bird feeder sure ain't bad. Project FeederWatch is a winter-long project of birds that visit feeders in backyards, nature centers, community areas, and other locales in North America. By counting birds at your feeder you help scientists to broadscale movements of winter-bird populations and long-term trends in bird distribution and abundance. You count birds at your count site that are there because of something you have provided (plantings, food, or water) and only report the highest number of individuals you see in view at one time, and then you report it online. Simple.

OTHER

 The Quake-Catcher Network (QCN )is a collaborative initiative for developing the world's largest, low-cost strong-motion seismic network by utilizing sensors in and attached to Internet-connected computers. The QCN obtains information about earthquake waves (seismic waves) by using computers that are connected to the Internet. Many laptop computers have built in sensors and desktop computers can utilize small USB sensors to collect the data. The data from these sensors are collected only when the computer is turned on and idle and is sent over the Internet. It is safe and easy. All you need to do is download the program.

 I used to take my ecology lab students out to cemeteries so we could collect data to make life tables. They were always a little squeemish at first but ended up loving the work. The Gravestone Project aims to map the location of a graveyards around the globe and then use marble gravestones in those graveyards to measure the weathering rate of marble at that location. The weathering rates of gravestones are an indication of changes in the acidity of rainfall between locations and over time and could be used as a measure of changes in climate and pollution levels. You go to your local graveyard and take a few measurements such as the lead lettering or headstone thickness.

The bodyLab is a project that researches the evolution of human body shapes and our ideas of attractiveness. All you have to do is go to the website and rate the silhouettes of women and/or men based on if you find that body shape attractive. It is so easy to do you don't even need to create an account.

The Sound Around You is building a sound map of the world as part of a new study into how sounds in our everyday environment make us feel. All you do is use your mobile phones (or another audio recording device if your phone is not compatible) to record 10-15 second clips from different sound environments, or ‘soundscapes’ from a family car journey to a busy shopping center, and to upload them to the virtual map, along with your opinions of them and why you chose to record it.

Dognition is a site that offers dog owners a series of science-based games that determine their dog's unique abilities and their relative strengths and weaknesses in various thinking skills. These skills range from empathy to cunning to memorization. As a user, you enter the results of your dog's behaviors, contributing to a data set that can be used by researchers studying dog cognition. It also offers the owners a "window into [their] dog's mind, offering a first step on the path toward improved behavior." You can tell how your dog sees the world and how they respond in different situations while at the same time contributing to science. Note: As of now this site/service has a fee.

WEBSITES FOR FINDING CITIZEN SCIENCE PROJECTS

This is the best website I have found for finding a project that suits you. It has a great search engine and describes the projects very well. It also includes many local projects as well as great projects for kids.

This site is less detailed and contains fewer projects but is still a good source for citizen science.


(top image from thisgreenblog.com)