Behaviour 2019
Can you have it all? Links between developmental plasticity and reproductive investment in spiders  
Luciana Baruffaldi, Laini Taylor, Yousef Safar, Vighnesh Sukhu, Maydianne CB Andrade. University of Toronto at Scarborough, Toronto, Ontario, Canada

Adaptive developmental plasticity allows an organism to shift life history allocation in response
to conditions experienced during ontogeny. Variable factors such as mate/rival presence or diet may change the trajectory of individual development to suite the context indicated by those cues. We tested the effect of diet and the presence of adult females/males on males’ developmental time, size/mass, and sexually selected traits in Latrodectus hasselti, a scramble-competing widow spider. Final-instar males were divided into 4 treatments in a 2x2 design in which female presence/absence was crossed with diet (high/low) and compared to a standardized control (medium diet/ no social cues). Our results indicate that diet affects the resources available to development and mass, with low diets imposing significant survival costs on males. Nevertheless, low diet males maintained high sperm production and running performance, comparable to males on higher diets. Moreover, although female presence alone did not have an effect, comparison to the control suggests that social cues from conspecifics may accelerate development. We discuss implication for understanding adaptive plasticity in spiders