Dr Leilani Walker
Back in 2015 I attended a talk by Lloyd Spencer Davis who was promoting his new book Professor Penguin: Discovery and Adventure With Penguins.
One of the stories he told was that of biologist George Murray Levick, medical officer on Captain Scott’s ill-fated Terra Nova expedition to the South Pole in 1910. As a consequence of the expedition, he was the first person to observe an entire breeding season at the Camp Adare Adélie penguin colony.
Levick was so shocked to observe instances of “sexual coercion” and even necrophilia by the male penguins that he recorded his observations in Greek to make them unreadable by the general public. Following his return to England, he did eventually publish a paper titled “Natural History of the Adélie Penguin” however the instances of “astonishing depravity” that he observed were removed in the interest of decency and would not be published until 2012.
This story of Edwardian ideals and the little regard that Adélie penguins have for them illustrates that, while science may need us to act as disinterested parties, our perception of human behaviour can colour our feelings about the activities of non-humans. It is perhaps unsurprising then that biases about gender and sex influence our interpretations of animal behaviour, especially in studies on sexual selection. A subset of natural selection, sexual selection is concerned with the evolution of body parts and behaviours that help an animal to produce as many high quality offspring as possible. Sexual selection governs the development of massive male weapons, bright colours, complex songs and countless other adaptations that are used when males and females interact.
However, gender stereotypes continue to influence scientific interpretations of these sexually selected characteristics, most obvious in the use of loaded language as found in a 2011 survey of the top 30 cited scientific articles relating to “sexual conflict” by Kristina Karlsson Green and Josefin Madjidian at Sweden’s Lund University. Studies of sexual conflict investigate what happens when males and females of a single species come into opposition while trying to maximise their own reproductive success. Sexual cannibalism is the most extreme example of sexual conflict, but less extreme versions include male waterstriders which have clasping structures on their abdomens to help them grab potential mates while females of those same species bear uncomfortable looking spines to discourage this behaviour.
In the surveyed studies, males were described using active words. Males would use “manipulation”, “intimidation”, and even “persuasion” while females were consistently framed as reactive: “resisting” males and but eventually “accepting” them. By contrast, in articles on sexual cannibalism, female spiders and praying mantises were “rapacious” or “voracious” while males would “sacrifice” themselves. Though generally understood terms can have specific definitions in science, this is not what’s happening here. Indeed such qualifiers would require an insight into an animal’s emotions and wants that is impossible when studying non-human animals. The authors of each literature review conclude that this loaded language was the resut of human stereotypes of gender, specifically that men like sex more than women and will enthusiastically pursue it while women are more picky and reticent (or in cases of sexual cannibalism, are femme fatales).
Further colouring is applied when such research is repackaged for mainstream media. Back in 2013, University of Auckland researchers observed native male praying mantises (Orthodera novaezealandiae) being attracted to and then cannibalised by invasive female Springbok mantises (Miomantis caffra). A quick Google search of the media releases for this research brings forth even more loaded descriptions. These “delicate” males are “hapless” or “naive” and “enthusiastically” “woo” these “sexy” “interlopers”. Emotive language is more enjoyable to read but they often make claims about an animal’s intentions that we can simply never be sure about.
En masse, this careless application of stereotypes can divert researchers past entire fields of study. In his 1871 publication, The descent of man and selection in relation to sex, Charles Darwin outlines sexual selection, explaining that it is the consequence of “direct competition between males” and “female choosiness”. Following Darwin’s publication, geneticist, Thomas Hunt Morgan (1903) was incredulous that “still another process of selection is going on [in addition to male-male competition]…that those females whose taste has soared a little higher than that of the average…select males…No doubt an interesting fiction could be built up along these lines, but would anyone believe it…?”. While male-male competition, was readily accepted at the time of publication, female choice would not be seriously considered as a significant factor in sexual selection until the 1960s and not broadly accepted until the 1980s.
This unconscious dismissal of the idea that female animals may play an important role in sexual selection continues this side of the millennium. More recently in 2014, in surveying almost 400 scientific articles studying animal genitalia, Malin Ah-King and colleagues found 177 studies of only the male’s genitalia compared to 28 studies of only the female’s genitalia (the remainder included research on both). The researchers cite this result as further evidence that male bias continues to steer researchers towards considering male subjects first at the exclusion of females on the persistent assumption that females are passive players in sex and reproduction.
It is possible that reversing this historic bias and avoiding future unnecessary detours may be as “simple” as ensuring that there is diversity in the researchers setting research directions. However, in the same review of animal genitalia studies, while most of the literature had men as their first authors (261/364), the pre-occupation with male genitalia was still present in the studies led by women. This suggests that biases within the scientific consensus will perpetuate themselves unless consciously and deliberately addressed.
In this way, fixing the bias within sexual selection studies is not only a case of pursuing within the field but recognising that gender stereotypes are baked into its very foundations. The kind of the question asked determines the kind of answer found and without conscious appraisal of what those questions are, and who is asking the questions, unconscious bias will continue to guide science into the future.
Dr Leilani Walker recently completed her doctorate from The University of Auckland. Her research examines the evolution of exaggerated male weaponry in New Zealand sheet-web spiders.
Featured image: Christopher Michel, Flickr CC BY 2.0.