ALBERT

Description: Individuals may vary consistently in their architectural makeup of the constructions they build, which might have tremendous implications for their ecology and fitness. In particular, the relationship between individual differences in architectural constructions and behavior (i.e., animal personalities) is largely unexplored. Individual black widow spiders, Latrodectus hesperus , build a 3D cobweb made up of distinctive components serving to support foraging (gumfooted lines) or antipredator protection (structural lines). To explore the relationship between individual differences in behavior and architectural constructions, we quantified 1) the level of consistent individual variation in several elements of web structure and 2) the level of consistent individual variation in foraging behavior and its relationship with web structure. We controlled for condition-dependent or environmental effects by satiating all spiders prior to assays and maintaining them in standardized conditions. Spiders exhibited consistent differences in the number of gumfooted lines they built for capturing preys and overall web weight, but not in the number of structural lines. Individuals also varied consistently in their tendency to attack a prey cue, despite all spiders being satiated. Finally, spiders producing more gumfooted lines exhibited a higher tendency to attack the prey cue. Our results suggest that the architectural constructions may impact the expression of individual behavioral differences (or animal personalities) and suggest that individual behavior and extended phenotype may be part of alternative foraging strategies in L. hesperus .

Description: Architectural constructions allow animals to modify their environment in order to improve their reproductive success. Constructions also modulate the expression of individual behavior, ultimately affecting the presence and importance of animal personality within populations. The exact impact of constructions on personality is seldom investigated. We quantified experimentally the impact of web characteristics on individual foraging behavior in the Western black widow spider ( Latrodectus hesperus ). We assayed aggressiveness toward a prey cue, and boldness while individuals resided on their own web versus after being translocated onto webs built by con-specifics. We quantified the importance of individual differences in aggressiveness and boldness while accounting for differences in web characteristics. We tested for relationships between web building, aggressiveness, and boldness. Web characteristics affected spider aggressiveness and interacted with individual web-building behavior to explain up to a fifth of the variation in foraging aggression, but did not affect spider boldness. Even after accounting for web characteristics, individuals still exhibited important differences in aggressiveness. We detected no relationship between an individual’s aggressiveness behavioral type and the characteristics of the web it built. Surprisingly, web characteristics impacted aggressiveness differently from one individual to the next. Hence the effect of web characteristics on foraging behavior might depend on condition or past experience. Webs contributed mostly to the variation in aggressiveness within-individuals. Variation in web building behavior might affect the amount of consistent differences in foraging, mating, and anti-predator behavior among individuals and needs to be accounted for when quantifying individual variation in behavior in spiders.