by Annalee Newitz / io9.com
We call those deadly spiders with the red hourglass shapes on their abdomens “black widows” because they eat their mates as part of the sex act. But black widows are far from the only spiders who sexually cannibalize, and some insects and fish do it too. It’s just a natural part of some animals’ reproductive process. So why use a term like “widow” for a creature who has no notion of marriage, and who is part of a species that evolved to eat or be eaten during sex? That’s what British biologist Emily Burdfield-Steele and her colleagues wanted to find out.
Their hypothesis was that people, including scientists, were grossly misunderstanding spider reproduction because they couldn’t stop anthropomorphizing the creatures involved. Instead of seeing a natural spider sex act, they kept seeing “widows” and “male sacrifices.” Those are decidedly human ideas. To find out whether this anthropocentric bias was pervasive, the biologists conducted a survey of 47 scientific papers about sexual cannibalism, to see how the act was described. Not surprisingly, they discovered a lot of non-scientific (and inaccurate) terms like “rapacious” and “voracious” attributed to the females; the males were called “unwilling” and “suicidal” in some cases. They created a fascinating chart of the most popular human-centric terms used to describe the spidery experience of sexual cannibalism.
In their paper published earlier this month in Animal Behavior, the researchers describe what you’re seeing in this chart:
Frequency of terms used when describing male and female behaviour of sexually cannibalistic species considered separately for (a) studies in which cannibalism occurs before and/or during copulation (26 papers) and (b) studies in which cannibalism occurs only during and/or after copulation (17 papers), excluding reviews. See the appendices for references and excluded words. The frequency for each sex is the number of articles the term appears in, in the context of describing behaviour. Words were also classified by three independent observers as active (a), reactive (re) or neutral (n). Terms marked with an asterisk were classified differently by at least two of the parties and so could not be given an overall classification.
It’s fascinating to see how the females are more often described as “attacking” or “predatory” if they eat their mates before or during sex, versus afterwards. Maybe eating somebody after sex doesn’t strike us as being quite so aggressive?