Science and Sex Bias

Science, Sex Bias, and Mantises

Posted: July 21, 2016

This video is about sex bias in science. But to get there, we first need to talk about insect private parts… Like ya do.

I’m Anna and this is Gross Science.

Mantises are tricky to spot because they’re masters of camouflage. But for mantis researchers, finding them is only the beginning. How do you distinguish one species from another, especially when they look so similar? Usually, by looking at their penises.

Well… sort of. Male mantises don’t exactly have penises. They have these: a series of structures that help the male link up, hold on, and pass sperm to the ladies. And the shapes of these structures help researchers tell hundreds of otherwise similar species apart.

Now, this strategy makes some sense: male mantis parts do tend to be pretty conspicuous. But what about female mantises? Because of the focus on male genitalia, it’s difficult to determine what species a lady mantis belongs to. But, for the first time, researchers decided to see if female genitalia could be used to tell praying mantis species apart. And what they found so far is that female genitals are indeed pretty different between groups.

In fact, by examining mantis lady parts, scientists just identified a whole new species. They described this praying mantis using the female’s unique genitals along with more traditional characterics, like where it lives, what it looks like and, yes, the male's genitals, too.

To honor this historic moment in mantis science, researchers named the insect Ilomantis ginsburgae after Ruth Bader Ginsburg, the Supreme Court justice who is a champion for women’s rights. This female-based research approach is one small step towards making our exploration of the tree of life more rigorous.

Unfortunately, sex bias in research has an impact even closer to home. It affects medicine, too. Male lab animals are more often used in research than females because the ladies were thought to confound experiments with their pesky hormonal fluctuations. But while studies in female mice suggest that this concern is totally unfounded, the bias persisted for decades. For example, at least 63% of pharmaceutical drug studies surveyed from 2009 used only male mice. And many scientific studies haven’t even bothered to list the sex of the animals at all.

To fix this problem, the National Institutes of Health have just started requiring researchers to label the sex of their animals and to use females whenever appropriate. But rodents are only half the battle. Until recently, human females were also studied less than their male counterparts in medical research. Some scientists hypothesize that this bias might explain why people with two X chromosomes more often experience adverse effects from medicines than people with an X and Y. It wasn’t until 1993 that the NIH actually required that women and people of color be included as subjects in clinical trials. (And by the way, inequalities in medicine based on race could and should be its own Gross Science video. So stay tuned.)

Anyway, there are many ways in which all humans are the same and require similar care. But where there are differences between people—whether they’re based on sex, or race, or something else—it’s important for us to study rather than ignore them. Otherwise, our medical system won’t be able to adequately care for everyone. And that’s gross.

Ew.

PRODUCTION CREDITS

Host, Producer, Animator, Editor

Anna Rothschild

Writer, Illustrator, Camera Sound

Eben E. B. Bein

Original Footage

©WGBH Educational Foundation 2016

Swing Club E

Music Provided by APM

IMAGES

Images of Ilomantis ginsburgae and mantis genitalia

Courtesy Sydney Brannoch

U.S. Supreme Court Justices Pose for Group Photo/Ruth Bader Ginsburg

©Getty Images/Mark Wilson

Praying Mantis, Insect, Green

Pixabay/fill

Adult female Deroplatys desiccata photographed at Bristol Zoo in 2007

Wikimedia Commons/Adrian Pingstone

Choeradodis sp. Hooded Mantis - Cayo District, Belize

Flickr/Thomas Shahan

Camouflage: Flower Mantis Hymenopus coronatus on Phalenopsis orchid

Wikimedia Commons/Philipp Psurek

Praying Mantis by clearlyambiguous

Wikimedia Commons/Scott Robinson

Sphodromantis viridis

Wikimedia Commons/Mintz_I

SFX

Cockroaches

Freesound/StateAardvark­
(used with permission from author)

Squeak Pack/squeak_10

Freesound/Corsica_S

Bubbles Popping

Freesound/ch0cchi

Insect Trill

Freesound/metamorphmuses

Swishes

Freesound/Pogotron

Wink

Freesound/bennychico11

Royal ping

Freesound/faston

Poof of Smoke

Freesound/planman

Textmarkerpapier

Freesound/hannagreen

Pencil

Freesound/faston

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Freesound/schluppipuppie

Marker Writing on Paper

Freesound/ftpalad

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Freesound/joedeshon

Slide whistle up 01

Freesound/joedeshon

Produced by WGBH for PBS Digital Studios

POSTER IMAGE

U.S. Supreme Court Justices Pose for Group Photo/Ruth Bader Ginsburg

©Getty Images/Mark Wilson

Mantis

©WGBH Educational Foundation 2016

Want more info?

2016 study using female genitalia to identify mantis species:
http://bit.ly/29ullza/

2011 study surveying the use of male and female animals in research papers published in 2009:
http://bit.ly/1rsqCv5

2014 study debunking the myth that femal mice are more variable than male mice:
http://bit.ly/299gCRm

2016 Washington Post piece about Ilomantis ginsburgae:
http://wapo.st/22yfiLf

2015 Nature Neuroscience article on how female mice process pain differently from male mice:
http://bit.ly/24UbwM1

2015 report on the number of women in clinical trials:
http://1.usa.gov/1GDMLxo

2015 release of the NIH’s new policy to include sex as a biological variable:
http://1.usa.gov/1PwtvB0

2007 review article on how drugs affect sexes differently:
http://bit.ly/24UbwM1

2014 news stories on sex bias from NPR, the Boston Globe, and Nature:
http://n.pr/1PDzVya
http://bit.ly/1S7dtgR
http://go.nature.com/1XrQi90

A 2006 commentary on how sex bias negatively impacts women’s health:
http://bit.ly/1YuWrjN