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The extraordinary diversity and ecological success of the social insects has been attributed to their ability to cope with the rich and often infectious microbial community inhabiting their nests and feeding sites. Mechanisms of disease control used by eusocial species include antibiotic glandular secretions, mutual grooming, removal of diseased individuals from the nest, and the innate and adaptive immune responses of colony members. Here we demonstrate that after a challenge exposure to the entomopathogenic fungus Metarhizium anisopliae, dampwood termites Zootermopsis angusticollis have higher survivorship when individuals develop immunity as group members. Furthermore, termites significantly improve their ability to resist infection when they are placed in contact with previously immunized nestmates. This ''social transfer'' of infection resistance, a previously unrecognized mechanism of disease control in the social insects, could explain how group living may improve the survivorship of colony members despite the increased risks of pathogen transmission that can accompany sociality.

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Ant foraging is a collective process composed of the activities of individuals as well as behaviorally integrated groups. Therefore, a great challenge in the socioecology of foraging is to explain how the behavior of such a potentially large and complex system as an ant colony emerges as a function of the properties of its individual components. The task of studying foraging in ants in simplified by the fact that foragers, owing to their sterility, may do little more than forage during their tenure as food harvesters. However, eusociality penetrates virtually every facet of foraging strategy and adds additional complicating social dimensions to its analysis.Individual and social processes of foraging can be categorized into com ponents to facilitate the analysis of foraging at the level of the single worker, the colony, or the integration of both (Table 1). A generalized ethogram of forager behavior can be described to illustrate these processes. A forager leaves the nest entrance in either a random or a consistent direction. A travel phase ensues, during which the worker maintains a constant compass bearing and moves directly away from the nest. At some point during the travel phase the forager shows a high frequency of turning, marking the beginning of search. During search, food resources are encountered and selected based upon a forager's physical caste, age, and prior experience, the trip distance, thermal stress, resource quality, and the colony's current nutritional status. Depending on the ant species and the size, density, or quality of the food, the forager may communicate information to nestmates about its location and recruit additional foragers.Summing the above-described individual activities across all foragers yields the most basic aspect of cooperative foraging. Changing nutritional demands associated with the maturation of reproductives may shift a colony's 191