Trick or Treat! – Mullerian Mimicry Edition

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Photo Credit: Jennifer Taylor (All Rights Reserved; Used with Permission)

You are never to young for a meta-costume*.

To the untrained eye, it may look like my daughter is dressed as a monarch butterfly for Halloween. To the trained eye, you will recognize that half of her parental set is extremely dorky.

She is actually going as the concept of Müllerian Mimicry instantiated in the form of a viceroy butterfly. This costume is occassionally mistaken for Batesian Mimicry by novices.

Butterfly (monarch) on a Penta by Arturo Yee (CC BY 2.0)
Butterfly (monarch) on a Penta by Arturo Yee (CC BY 2.0)
Viceroy by Rodney Campbell (CC BY 2.0)
Viceroy by Rodney Campbell (CC BY 2.0)

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Getting grumpy about PMS paper

On 11 August 2014, Michael R. Gillings published a paper in Evolutionary Applications entitled “Were there evolutionary advantages to premenstrual syndrome?” There is a strain of thinking that is common in the general public, but is also frequently found among academic researchers that I call adaptionism. This line of thinking assumes that, if a biological phenomenon exists, it must be there as the result of natural selection – i.e., be adaptive. This makes things like PMS seem like a great, evolutionary mystery to be “solved”.

Premenstrual syndrome (PMS) affects up to 80% of women, often leading to significant personal, social and economic costs. When apparently maladaptive states are widespread, they sometimes confer a hidden advantage, or did so in our evolutionary past. –from the abstract, Matthew R. Gillings (DOI: 10.1111/eva.12190)

I could spend pages on the problems with this approach to such a question. Fortunately for you and I, Kathryn Clancy, who is far more knowledgable on the relevant evolutionary anthropology than you and I, gutted this paper for The Daily Beast earlier this week:

…the fact that PMS is heritable and variable tells us nothing about whether women with PMS have more children than those who don’t, and this is the true test for adaptation. This crucial point—the third and most crucial condition for natural selection—is absent from the paper.
Kathryn Clancy



Ow, My Head

Unlike the widespread reporting of the credulous media, the human skull is not specifically evolved to take a punch from other humans. Brian Switek explains the many problems with this hypothesis at National Geographic’s Phenomena. I admit that I thought, throughout my rugby career, that my head, and only my head, had evolved to be punched. It turns out that the way I played rugby had evolved to make people want to punch me in the head1. I was a particularly annoying person to play rugby against2.

Fortunately, human skulls are pretty robust in some key ways. It is just very unlikely that they got that way due to the evolutionary pressure of hominids punching each other in the noodle. One of the key problems with the punching hypothesis is that it is pure conjecture (and unreasonable conjecture, at that) without supporting experimental evidence. What would it take to really test the punching hypothesis?

WARNING: This post may contain a Game of Thrones spoiler “below the fold”. 

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Human population structure is such that it would require either (or both) a strong selection pressure or a big increase in fitness for natural selection to dominate the evolutionary dynamics. I submit as evidence that humans were not subject to intense selection pressure from predation one word: crying, specifically the crying of small children.

The idea that a primitive band of reproductively successful humans could remain hidden from things like leopards boggles the mind of this father. And, I have thought this for a long time, before I had children. It is in no way related to the fundamental conflicts generated by bed time and potty training in the mind of a two year old child. Nothing at all.

The Art of Science: Wallace’s Flying Frog


Last week, the Natural History Museum in London unveiled a digital archive of the letters of 19th century naturalist Alfred Russel Wallace, the co-discoverer with Charles Darwin, of evolution by natural selection. The archive, introduced on the 100th anniversary of Wallace’s death, naturally focuses on his writings, but also contains some paintings and drawings. Wallace, who spent years in far-flung places collecting specimens, didn’t have the option of pulling out a camera to document his finds. He often sketched or painted his discoveries, including this lovely watercolor of a flying frog which he painted in Sarawak. It may not be Audubon-level in its artistry and detail, but it’s a useful scientific illustration which also has great personality and charm.