Spectacular examples of cooperative behavior emerge among a variety of animals and may serve critical roles in fitness [1, 2]. However, the rules governing such behavior have been difficult to elucidate [2]. Drosophila larvae are known to socially aggregate [3, 4] and use vision, mechanosensation, and gustation to recognize each other [5-8]. We describe here a model experimental system of cooperative behavior involving Drosophila larvae. While foraging in liquid food, larvae are observed to align themselves and coordinate their movements in order to drag a common air cavity and dig deeper. Large-scale cooperation is required to maintain contiguous air contact across the posterior breathing spiracles. On the basis of a directed genetic screen we find that vision plays a key role in cluster dynamics. Our experiments show that blind larvae form fewer clusters and dig less efficiently than wild-type and that socially isolated larvae behave as if they were blind. Furthermore, we observed that blind and socially isolated larvae do not integrate effectively into wild-type clusters. Behavioral data indicate that vision and social experience are required to coordinate precise movements between pairs of larvae, therefore increasing the degree of cooperativity within a cluster. Hence, we hypothesize that vision and social experience allow Drosophila larvae to assemble cooperative digging groups leading to more effective feeding and potential evasion of predators. Most importantly, these results indicate that control over membership of such a cooperative group can be regulated.

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Highlights d Rh6-PR/lOLP pathway in the visual system controls fruit fly larvae social behavior d Rh6-PR/lOLP pathway represents a movement-detecting module d Proper development of Rh6-PR/lOLP pathway requires exposure to light and other larvae d Experience-dependent changes occur pre-and postsynaptically in Rh6-PR/lOLP pathway

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Populations of the eastern oyster (Crassostrea virginica) have experienced declines from overfishing and disease throughout much of its U.S. range, though development of maximum sustainable yield (MSY) management criteria has been elusive. This is due in part to the discordance between oyster spawning stock and recruits as the classic stock-recruitment model does not account for the requirement of shell substrate on which recruits settle. This issue was recently addressed with the development of a surface area-recruitment model, which is herein incorporated into a simulation analysis to estimate MSY-based reference points for C. virginica in the Delaware Bay. Simulations demonstrate that at low natural mortality, fishing mortality (F) may be sustainable at values between 10 and 15%, however if disease or other mortality-enhancing processes occur, the margin of error in fishing is small and may quickly lead to population and reef collapse, emphasizing a precautionary F < 10%. The MSY-based reference points generated here provide rebuilding goals for the oyster fishery and reef management on fished and unfished reefs, and the framework from which shell-planting can be incorporated and optimized in the future.

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