Difficult to believe this is love: Sexual cannibalism
Sexual cannibalism has fascinated biologists ever since the days of Charles Darwin.It’s a behaviour in which one member of a courting or copulating male-female pair consumes the other,seen among mantises and other invertebrates, including spiders, midges and perhaps horned nudibranchs.
“If you put a pair together and come back later, you’ll just find the wings of the male and no other evidence he was ever there,” — William Brown, an evolutionary biologist at the State University of New York in Fredonia.
Biologists came up with various explanation to explain this behaviour among animals like that it evolved because the males of some species could get an evolutionary advantage from being eaten or that males can increase their chances of passing on their genes if they cooperate in their own death.Dr. Stephen jay Gould argued that sexual cannibalism was too rare to be significant and he was of the opinion that females eat their mates simply because they mistake them for prey.
To understand and to know in depth the ecology and evolution of sexual cannibalism ,Jordi Moya-Laraño and other authors performed field experiments on Mediterranean tarantula (Lycosa tarantula), a burrowing wolf spider.The authors are of the opinion that this would be better way to understand this strange behaviour and its benefits to females as previous all studies were performed in lab conditions .
The following are the conclusion drawn after the field experiments performed by Rabaneda-Bueno R, et al. and detail results of which are published in open access journal PLOS ONE.
1) In natural conditions decent fraction of female L. tarantula kill and eat approaching male without mating and this is more often if the female is already mated.
2) Cannibalistic females have higher rates of reproduction, and produce higher-quality offspring, when compared to non-cannibalistic females.
3) sexual cannibalism is adaptive to females.
Citation:
Rabaneda-Bueno R, Rodríguez-Gironés MÁ, Aguado-de-la-Paz S, Fernández-Montraveta C, De Mas E, et al. (2008) Sexual Cannibalism: High Incidence in a Natural Population with Benefits to Females. PLoS ONE 3(10): e3484. doi:10.1371/journal.pone.0003484
Image Credit:
Roger smith / Flickr
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