Participation in cooperative prey capture and the benefits gained from it are associated with individual personality

In animal societies, behavioral idiosyncrasies of the individuals often guide which tasks theyshould perform. Such personality-specific task participation can increase individual task efficiency,thereby improving group performance. While several recent studies have documented group-levelbenefits of within-group behavioral （i.e., personality） diversity, how these benefits are realized atthe individual level is unclear. Here we probe the individual-level benefits of personality-driven taskparticipation in the social spider Stegodyphus dumicola. In S. dumicola, the presence of at leastone highly bold individual catalyzes foraging behavior in shy colony members, and all group con-stituents heavily compete for prey. We assessed boldness by examining how quickly spidersresumed normal movement after a simulated predator attack. We test here whether （1） participantsin collective foraging gain more mass from prey items and （2） whether bold individuals are less re-sistant to starvation than shy spiders, which would motivate the bold individuals to forage more.Next, we assembled colonies of shy spiders with and without a bold individual, added one preyitem, and then tracked the mass gain of each individual spider after this single feeding event. Wefound that spiders that participated in prey capture （whether bold or shy） gained more mass thannonparticipators, and colonies containing a single bold spider gained more total mass than purelyshy colonies. We also found that bold spiders participated in more collective foraging events andwere more susceptible to starvation than shy spiders, suggesting that the aggressive foraging ofbold individuals may represent a strategy to offset starvation risk. These findings add to the bodyof evidence that animal personality can shape social organization, individual performance, andgroup success.

Polistes metricus queens exhibit personality variation and behavioral syndromes

Consistent differences in behavior between individuals, otherwise known as animal personalities, have become a staple in behavioral ecology due to their ability to explain a wide range of phenomena. Social organisms are especially serviceable to animal personality techniques because they can be used to explore behavioral variation at both the individual and group level. Despite the suc- cess of personality research in social organisms generally, and social Hymenoptera in particular, social wasps （Vespidae） have received little to no attention in the personality literature. In the pre- sent study, we test Polistes metricus （Vespidae; Polistinae） paper wasp queens for the presence of repeatable variation in, and correlations （＂behavioral syndromes＂） between, several commonly used personality metrics： boldness, aggressiveness, exploration, and activity. Our results indicate that P. metricus queens exhibit personalities for all measured traits and correlations between differ- ent behavioral measures. Given that paper wasps have served as a model organism for a wide range of phenomena such as kin selection, dominance hierarchies, mate choice, facial recognition, social parasitism, and chemical recognition, we hope that our results will motivate researchers to explore whether, or to what degree, queen personality is important in their research programs.

Cuticular bacteria appear detrimental to social spiders in mixed but not monoculture exposure

Much of an animal＇s health status, life history, and behavior are dictated by interactions with its endogenous and exogenous bacterial communities. Unfortunately, interactions between hosts and members of their resident bacterial community are often ignored in animal behavior and behavioral ecology. Here, we aim to identify the nature of host-microbe interactions in a nonmodel organism, the African social spider Stegodyphus dumicola. We collected and identified bacteria from the cuticles of spiders in situ and then exposed spiders to bacterial monocultures cultures via topical application or injection. We also topically inoculated spiders with a concomitant ＂cocktail＂ of bacteria and measured the behavior of spiders daily for 24 days after inoculation. Lastly, we collected and identified bacteria from the cuticles of prey items in the capture webs of spiders, and then fed spiders domestic crickets which had been injected with these bacteria. We also injected 1 species of prey-borne bacteria into the hemolymph of spiders. Only Bacillus thuringiensis caused increased mortality when injected into the hemolymph of spiders, whereas no bacterial monocultures caused increased mortality when applied topically, relative to control solutions. However, a bacterial cocktail of cuticular bacteria caused weight loss and mortality when applied topically, yet did not detectibly alter spider behavior. Consuming prey injected with prey-borne bacteria was associated with an elongated lifespan in spiders. Thus, indirect evidence from multiple experiments suggests that the effects of these bacteria on spider survivorship appear contingent on their mode of colonization and whether they are applied in monoculture or within a mixed cocktail. We urge that follow-up studies should test these host-microbe interactions across different social contexts to determine the role that microbes play in colony performance.

Smaller and bolder prey snails have higher survival in staged encounters with the sea star Pisaster giganteus

Temporally consistent individual differences in behavior, also known as animal personality, can have large impacts on individual fitness. Here, we explore the degree to which individual differences in anti-predator response （or boldness） influence survival rates in groups of snails Chlorostoma funebralis when they encounter a predatory sea star Pisaster giganteus. The snail C. funebralis shows consistent individual variation in predator response where some fearful snails actively flee bodies of water occupied by predators whereas bolder snails consistently do not. We show here that bold snails are significantly more likely to survive encounters with a predatory sea star and, somewhat counterintuitively, fearful snails actually suffer higher mortality rates. We also found that smaller snails and those occurring at higher experimental densities experienced higher per capita survival rates. Positive effects of prey boldness on survival are not uncommonly reported in the animal personality literature; however, such results are inconsistent with classic animal personality theory borrowed from the optimal foraging literature. The findings herein add to the growing body of evidence that consistent individual differences in behavior can impact predator-prey interactions and that boldness is potentially under positive predator-driven selection in some systems.

Group dynamics and relocation decisions of a trap-building predator are differentially affected by biotic and abiotic factors

Most habitats in nature are heterogeneous, incorporating favorable and unfavorable microhabitats for different animals, based on their ecological niche. Unsuitable microhabitats have negative consequences for individual growth and survival. Animals, therefore, should fine-tune their location within the habitat by dispersing away from such microhabitats. We studied the suitability of different constant microhabitat conditions for wormlion larvae, a trap-building predator, tested in groups under laboratory conditions. Wormlions construct pit-traps in loose soil and capture small arthropod prey. As wormlions occur in high densities in nature, testing in groups is thus more indicative of their natural behavior than testing individuals. Wormlions responded strongly to biotic conditions--high conspecific density, starvation, and large body mass of conspecifics--by either increasing pit-relocation events or moving away from the microhabitat center to the periphery of the arena, probably opting for a way out. In other instances, individuals increased their distance to the nearest neighbor, thereby changing the spatial pattern toward a more regular pattern, potentially indicating interference competition. The only abiotic condition apparently perceived by wormlions as unsuitable was shallow sand, which led to frequent relocations. The two other abiotic factors--illumination and sand particle size--had no observable effect on behavior, although wormlions in nature always occur under shade in fine sand, and prefer both shade and fine sand particle size under laboratory conditions when given a choice. Under the fine spatial scale of the present experiment, biotic factors appear to be more influential than abiotic ones.