Water Wigs

This is one of those artsy posts that's only tangentially sciency. And by that I mean that it involves water in neat ways. But the photography is beautiful and funny at the same time.

What happens when you drop water balloons on a bunch of bald guys? You take pictures.

Tim Tadder is a photographer who did just that. He "found a bunch of awesome bald men and hurled water balloons at their heads, to capture the explosion of water at various intervals. The result [is] a new head of water hair!" A laser and a sound trigger was used to capture the right moments for each subject and create a "head of hair" that best fit with the man's face. The colors of the lasers add wonderful, visual interest in these amusing photos. Here are a few of my favorites:

See more of these pictures and other projects at:
Tim Tadder's Website
Tim Tadder's Page on the Behance Network

Captain Planet: The Trailer

A fan-made Captain Planet trailer. So well done, I would see this!

How to Leave the Planet

Douglas Adams is one of my favorite writers. He is best known for The Hitchhiker's Guide to the Galaxy but has other works you should check out too. This just reinforces the nerd-love:

The Mother-in-Law Conflict

Your mother-in-law. And the need she feels to help you raise your kids. Blame menopause. And evolution.

Humans are a cooperative breeding society. We live in extended family-groups in which both "breeders" and "non-breeders" contribute in rearing the offspring. However, humans are one of the select few species (including pilot whales and killer whales) that are known to stop reproducing long before we die. This means that a significant proportion of this cooperation includes non-breeding helpers in the form of post-menopausal women. As with most things in science, there are hypotheses that to try to explain this structure. Two of these are the Mother and Grandmother Hypotheses. Basically, they say that reproducing late in life is costly but that there are indirect benefits to increasing the reproductive success of your offspring. That makes sense when looking for reasons for the evolution of menopause, if you are going to die if you have late-in-life babies then it is probably beneficial to remove the ability to do so. But the reality is that, in humans, the death risk is only 3 percent before menopause, and that's in societies lacking modern medicine. So maybe there is another reason. Enter the inclusive fitness theory. This is often used to describe social insect societies and non-sterile helpers in cooperative breeding invertebrates. However, this theory typically ignores age-specific reproductive overlap between generations of females. Mix a little game-theory modeling in there and you get the Reproductive Conflict Hypothesis. This postulates that the conflict between mothers and their adult offspring selects against late-life reproduction which may, in turn, select against increasing ages of fertility. Perhaps now would time to point out that in this case we are not talking about the shouting-match kind of conflict, but rather the reproductive conflict between generations.

A new study, published this week in Ecology Letters, tests the hypothesis that this conflict between genetically unrelated generations of women (which I will name and heretofore call the mother-in-law conflict or MILC <--that's a good one right?!) could have promoted the evolution of menopause. Are you are causing your mother-in-law to become sterile? Evolutionarily speaking, of course. The authors of this study used a large data set from Finland that cataloged birth, death and marriage records kept by the Lutheran church between 1702 and 1908. They wanted to know if MILC really exists, what the consequences of it are, and which hypothesis best explained the evolution of menopause.

The researchers found that MILC is an important component. They found that the chances of children dying increased when mothers-in-law and daughters-in-law gave birth around the same time. The simultaneous reproduction of these generations was associated with a decline of 66 percent in offspring survival. Additionally, the children of the older women had 50 percent lower survival. Those are pretty large numbers which suggests that it is highly beneficial for the mothers-in-law not to have children. When using the inclusive fitness model, they found that when the in-law generations reproduced at the same time, there was a strong selection against women remaining fertile after age 51. So which hypothesis explains these changes in inclusive fitness? As it turns out, the Reproductive Conflict Hypothesis and the Grandmother Hypothesis contributed about the same while the Mother Hypothesis had no real effect. Essentially, there are more benefits to being a grandmother (and presumably helping raising your grandchildren) than there are in continuing to have children late in life. However, this study does not address the topic of plasticity in maintaining the ability to conceive late in life or the physiological explanations for the evolution of menopause. As always, more study is needed.

Mirkka Lahdenpera, Duncan O.S. Gillespie, Virpi Lummaa, & Andrew F. Russell (2012). Severe intergenerational reproductive conflict and the evolution of menopause Ecology Letters, Article first published online: 22 AUG 2012 DOI: 10.1111/j.1461-0248.2012.01851.x

Also:
Nature News article "In-law infighting boosted evolution of menopause"

We're NASA and We Know It

A timely Curiosity parody.

Freshman Survival Kit

OK, prepare yourself because I'm going to fly my nerd flag high. It is that time of year when college campuses around the country are being invaded by new and returning students. A labmate's daughter is starting her first year in college and so as a graduation present I put together a Freshman Survival Kit. I used the excuse of her being a science major to validate my nerd-out. Biologists love dichotomous keys and so why not put one together to tell her all about what is included in her kit. See? Nerd flag. Enjoy!

Lil' Giants of Science

"Carry this century's most notable scientific minds in your pocket. These miniature scientist action figures are colorful caricatures, and the perfect gift for any scientific fan. Fun for play and display, the set includes Darwin, Newton, Einstein, and Tesla. Size of each: 3" tall."

You can get your own The Scientists action figures over at Edmund Scientifics.

Or you can head over to Shakespeare's Den and get a set that includes Marie Curie.

Or maybe finger puppets are more your flavor...

 

Gifts for all occasions...check!

Carl Sagan's Apple Pie

(get a printable 4x6 recipe card here)

Castrating the Zombie Ant

Last year I posted Attack of the Zombie Ant! A post that turned out to be quite popular. To sum it up, there are fungal parasites (genus Ophiocordyceps) that infect ants and take control of their bodies. The fungus then compels the ant to crawl up into the forest canopy and clamp down on a leaf while the fungus grows inside the body, eventually producing a hyphae and stroma (fruiting body) that grows out of the head and produces and releases spores. And repeat.

A recent paper in PLoS ONE takes a closer look the coevolution between ant colonies and these rare, specialized fungi. Broadly, the term coevolution is used to describe how two or more species reciprocally affect each other's evolution. In the case of the zombie ants, it is host-parasite coevolution. The parasite evolves to infect the host, and the host evolves to resistant to the parasite. An arms race, if you will. The virulence and defense traits of specialized parasites, such as the zombie-ant fungi, are shaped by these arms races. This is even more true in species like Ophiocordyceps that rely on host behavior for their reproductive success. On the other side of the coevolutionary coin, ant colonies (in this case Formica and Camponotus ants) are long-lived and live in high density, continuously interacting colonies. This behavior has been shown to be a type of social immunity where there is a strong selection for efficient prophylactic defenses and where ant parasites pose a limited threat to infecting an entire colony. Meaning that individual ants my die from the fungal disease but that the mortality of the colony is low.

This paper specifically looks at the trade-offs experienced by Ophicordyceps manipulating ants into dying in nearby graveyards. When the fungus compels an ant to leave their nest and die close to their host colony, many infected individuals will end up in one area, forming high-density ant graveyards that may persist for years. Considering the life span of your average ant, that is a long time. The authors of this paper used data from previous studies of O. unilateralis in Thailand and collected a new data set from O. camponoti-rufipedis from Brazil to construct a developmental-stage-structured model describing this ant-fungus interaction. In this new collection, they identified ants infected with O. camponoti-rufipedis and marked areas covering entire graveyards, tagging all dead infected ants. Each cadaver ant was then characterized in terms of parasite development: (1) freshly killed ant, (2) dead ant with parasite stroma, (3) dead ant with mature fruiting body, (4) dead ant at stage 2 or 3, but hyperparasitized by other fungi, or (5) dead ant whose status could not be identified. To estimate the infectivity of the fungi's fruiting bodies, they collected a sample of dead ants and brought them to the lab for study. From these data, they were able to formalize the "life-cycle" of parasitized ants and calculate a growth rates and fungal developmental stage distributions of the graveyards.

The researchers found that only 6.5 percent of the O. camponoti-rufipedis fruiting bodies were effectively producing spores. Most of the dead ants that they found were sterile because they were either immature, damaged or hyperparasitized (secondarily parasite develops within a previously existing parasite). They also found that only 42 percent of the fruiting bodies were shooting spores at a particular time interval. When the apparently "healthy" cadaver ants were dissected, they found them to have been invaded by the larvae of small unidentified arthropods which may have reduced the likelihood of the fungi reaching maturity. Add to this that out of all of the ant colony members, only the foragers face the risk of encountering spores, then you end up seeing a rather low infection and transmission rate. So only if graveyards are stable or growing will infection levels be stable.

Interestingly, the authors found that the zombie-ant fungi are themselves vulnerable to attack by other parasites. Their model suggests that the stroma life stages or immature fruiting body stages are highly vulnerable to biotic attack. So much so that hyperparasitism is nearly negligible in the mature life stage. Whether that is because the mature life stage has a much more efficient immune defense or some other cause is unclear. What is clear is that hyperparasitic fungi prevent the infected zombie-ant fungus from spreading spores which, in turn, means that fewer of the ants will become zombies. This means that the rate of infections is much less than the size of some graveyards might suggest. It is known that O. unilateralis has a range of asexual stages (synanamorphs) with spores adapted for persistence or aerial dispersal. However, O. camponoti-rufipedis is known to produce a single anamorph. So the horizonatal transmission of this species may depend on the movement of the infected ants themselves. And that means all kinds of other intriguing studies may be in the works. Can't wait!


Sandra B. Andersen, Matthew Ferrari, Harry C. Evans, Simon L. Elliot, Jacobus J. Boomsma, & David P. Hughes (2012). Disease Dynamics in a Specialized Parasite of Ant Societies PLoS ONE, 7 (5) DOI: 10.1371/journal.pone.0036352


About the Authors:
Sandra Andersen's bio
David Hughes' Lab (includes zombie-ant videos on his Projects page)

Articles:
Penn State Science "The Zombie-Ant Fungus Is Under Attack, Research Reveals"
Discover Magazine "Zombie Ant Parasite Has Its Own Parasite - a Fungus that Attacks Fungi"
The Guardian "Zombie-ant parasitic fungus kept in check by hyperparasitic fungus"


(image from the Hughes Lab website)

Dirty Geologists

bow-chica-bow-wow...

The Curiosity Excuse

The Museum of Endangered Sounds

The Museum of Endangered Sounds is owned and operated by Brendan Chilcutt. He launched the site in 2012 as a way to archive and preserve the sounds made by old technologies and electronics equipment. Think about it... what sounds do you remember from your childhood that you just don't hear anymore? How about a dial-up modem, a VHS tape going in to a VCR, a dot matrix printer, or the sounds of your favorite video games. Check out the site and click around on some of the thumbnail images to hear some of these noises from gadgets from a bygone era. Oh geez...I'm now old enough to have lived in a "bygone era."

(http://savethesounds.info)

Here are a couple of additional stories on this topic:
Washington Post's article "Museum of Endangered Sounds enshrines audio from bygone era"
NPR story: "What's That Sound? Preserving The Noise of Old Gadgets"