Albo et al 2023. BMC Biology

Here, we tested the degree to which deceptive worthless gifts can occur in natural populations living under divergent environmental conditions (moderate and stressful) in a gift-giving spider. We examined the plasticity of morphological and behavioral traits and analyzed the fitness of females in relation to the gift type, also examining the paternity acquired by males offering either gift type. We demonstrated that worthless gifts can become dominant under highly stressful environmental conditions (84-100%). Individuals in such environment reach smaller sizes than those in moderate conditions. In contrast, males living under moderate conditions varied the use of the deceptive tactic (0-95%) and worthless gifts negatively influenced female fecundity. Further, male size, rather than gift content, positively impacted paternity success in the moderate but not in the stressful environment. Overall, this is the first empirical evidence that a reversible deceptive tactic can become dominant when the environment becomes harsh and mate choice becomes limited.