Exploiting a moment of weakness: male spiders escape sexual cannibalism by
copulating with moulting females
#MMPMID26607497
Uhl G
; Zimmer SM
; Renner D
; Schneider JM
Sci Rep
2015[Nov]; 5
(?): 16928
PMID26607497
show ga
Sexual cannibalism is a particularly extreme example of conflict between the
sexes, depriving the male of future reproduction. Theory predicts that sexual
conflict should induce counter-adaptations in the victim. Observations of male
spiders mating with moulting and hence largely immobile females suggest that this
behaviour functions to circumvent female control and cannibalism. However, we
lack quantitative estimates of natural frequencies and fitness consequences of
these unconventional matings. To understand the importance of mating while
moulting in cannibalistic mating systems, we combined mating experiments and
paternity assessment in the laboratory with extensive field observations using
the sexually cannibalistic orb-web spider Argiope bruennichi. Copulations with
moulting females resulted in 97% male survival compared with only 20% in
conventional matings. Mating while moulting provided similar paternity benefits
compared with conventional matings. Our findings support the hypothesis that
mating with moulting females evolved under sexual conflict and safely evades
sexual cannibalism. Despite male benefits, natural frequencies were estimated
around 44% and directly predicted by a male guarding a subadult female. Since
only adult females signal their presence, the difficulty for males to locate
subadult females might limit further spreading of mating with moulting females.
free
free
free
