Black widow spiders are known mainly for, well, being black widows. Now research published in the journal Animal Behaviour shows that males of the species destroy large sections of the female’s web during their courting behaviour. The excess silk would then be wrapped up within their own silk. The new research shows that the home-wrecking of the female’s web can deter rival males, by making the female’s web less attractive.
Despite the destruction of their webs the females don’t seem to mind it. Authors of the study, from Simon Fraser University, Canada, suggest the lack of a response from the females could show the benefits of not being viewed as a desirable mate, protecting her from unwanted harassment once mated and enabling better parenting.
And when we say harassment, there is severe completion for females; it has been recorded that as many as 40 male suitors can visit a female’s web. Males have been known to use other methods to prevent the female from mating, such as mating plugs and guarding behaviour, but this is the first time that destroying webs have been seen in the wild.
The research was based on letting the western black widow spider to build webs in movable cages in a lab over a week, the relocating the cages to a beach on Vancouver island , a natural habitat of the spiders. They removed the female spiders from the webs and monitored how many males arrived at each cage, containing 3 different types of web, intact, webs with half the silk cut out and bundled up by other males and another with half the silk removed with scissors and removed. The aim was to look at the removing the pheromone-laden silk is what made the webs less desirable or if wrapping the silk in males silk was also important. The results showed that the intact web had attracted 10 males in the first 6 hours AND the web with just removed silk were just as attractive were as the web with the males wrapped silk showed only a 3rd of the interest displayed by the other males.
These significant results show that this behaviour needs to be studied further to figure out why males bundling silk makes webs seem so much less appealing than just removed silk or intact silk.