Geographical differences in information use and plasticity of male mating decisions in a sexually cannibalistic spider
Final Report Abstract
To summarize our achievements, we have won valuable and novel insights into the complex mating strategies of Argiope bruennichi males, and explored how they integrate social information into their decision-making. Even though body sizes of males and females and phenology differ strongly between Southern and Northern populations, these differences appear to be mainly a result of phenotypic plasticity and maternal effects. Both females and males respond plastically to changing conditions. Size and time of maturity varied enormously in field collected spiders from both populations and almost converged after only one generation in a common garden (2015-) combined with a restricted feeding treatment. Our experiments revealed that males follow complex rules during mate search and choice, but we found few differences in mating strategies between geographical regions. Males find their first mating partner mostly through a random search, and then modulate their investment into the first copulation such that they consider the relative size (and fecundity) of the current mate in relation to neighboring females independently of absolute sizes of the females. We were able to reproduce field observations and observed bigyny when the first female was relatively smaller. Male mating decisions seem to rely on local information only, as the application of female cues during development or during mate search did not have strong effects on mating tactics. Such relative assessment and flexible responses facilitate rapid adjustment to novel conditions. The priming effect of female cues for earlier or delayed maturation further facilitates rapid adaptation to novel conditions. We conclude that the species’ mating system and developmental plasticity seem ideal pre-adaptations to variable conditions and pose no constraints to range expansion.
Publications
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(2020) Males of a sexually cannibalistic spider chemically assess relative female quality. BMC evolutionary biology 20 (1) 90
Cory, Anna-Lena; Schneider, Jutta M.
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2018. Effects of social information on life-history and mating tactics of males in the orb-web spider Argiope bruennichi. Ecology and Evolution 8:344–355
Cory A.L. & J.M. Schneider
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2018. Mate availability does not influence mating strategies in males of the sexually cannibalistic spider Argiope bruennichi. PeerJ 6:e5360
Cory A, Schneider JM
