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While a large body of research has focused on the physiological effects of multiple environmental stressors, how behavioural and life‐history plasticity mediate multiple‐stressor effects remains underexplored. Behavioural plasticity can not only drive organism‐level responses to stressors directly but can also mediate physiological responses. Here, we provide a conceptual framework incorporating four fundamental trade‐offs that explicitly link animal behaviour to life‐history‐based pathways for energy allocation, shaping the impact of multiple stressors on fitness. We first address how small‐scale behavioural changes can either mediate or drive conflicts between the effects of multiple stressors and alternative physiological responses. We then discuss how animal behaviour gives rise to three additional understudied and interrelated trade‐offs: balancing the benefits and risks of obtaining the energy needed to cope with stressors, allocation of energy between life‐history traits and stressor responses, and larger‐scale escape from stressors in space or time via large‐scale movement or dormancy. Finally, we outline how these trade‐offs interactively affect fitness and qualitative ecological outcomes resulting from multiple stressors. Our framework suggests that explicitly considering animal behaviour should enrich our mechanistic understanding of stressor effects, help explain extensive context dependence observed in these effects, and highlight promising avenues for future empirical and theoretical research. [ABSTRACT FROM AUTHOR]

Although studies of species linked by a common resource (i.e. ecological guilds) have so far mainly focused on competition and predation, guilds are also good places to find mutualism. In this review we consider some three- and four-species community modules to illustrate examples of wide relevance. Mutualism arises from various direct and indirect trophic and non-trophic interactions between species—and within modules both with and without intraguild predation. Species removal and augmentation experiments, other manipulations, direct measurements, and path-analytic methods can determine the presence and intensity of mutualism within guilds. Such studies, particularly when associated with existing theory and new theoretical development, can help advance an interaction-based approach to community analysis that recognizes linkages among mutualism, predation and competition in natural systems. [ABSTRACT FROM AUTHOR]

In principle, the intensity of sexual conflict is best measured as a loss of fitness associated with the expression of conflict-related traits. But because the relevant traits may be difficult to manipulate and fitness difficult to assess, proxy variables linked to conflict intensity may provide important tools for empirical measurement. Here we identify two common types of sexual conflict-one within mating pairs over the less expensive male role, and one between mating pairs and intruders seeking to obtain fertilizations-and consider how they vary in intensity along gradients of population density and predation risk. To do this, we develop and analyze a model of mating dynamics in the chalk bass, an egg-trading simultaneous hermaphrodite that lives on Caribbean coral reefs. In this species, within-pair sexual conflict leads each female-role partner to provide in each mating episode only a subset (parcel) of its egg clutch to its mate for fertilization. Pair-intruder sexual conflict (i.e., sperm competition) increases the proportion of the gonad allocated to male function. In the model, more parceling and greater male allocation both resulted in lower fitness at the ESS, our measure of conflict intensity. Male allocation increased along the density gradient but decreased along the predation-risk gradient, reflecting shifts in intrusion frequency. Parcel number sharply increased and then decreased more gradually along a gradient of increasing local density, initially responding to increased availability of alternative mates across low densities and then to diminishing clutch size toward higher densities. Parcel number decreased with predation risk as each mating episode became more dangerous. Conflict intensities were usually greatest at intermediate positions along the two environmental gradients, and each conflict ameliorated the intensity of the other. Overall, parceling and sex allocation may be good though imperfect proxies for intensities of within-pair and pair-intruder sexual conflicts among chalk bass. [ABSTRACT FROM AUTHOR]

Examines the characteristics of antlion foraging. Importance of patchiness of prey distributions over space and time; Components of antlion foraging strategies; Illustration of antlion foraging; Determination of net energy gain in antlion relocation strategies.

Quercus (oak) regeneration failure threatens many forest and savanna communities worldwide, where preservation of vegetation structure and composition depends on acorns germinating and surviving into adulthood. However, predation on the acorns and browsing of seedlings limits oak regeneration. To better understand the effects of these 2 mechanisms on oak recruitment in the endangered Bluegrass savanna-woodland of Kentucky, we compared seed predation and herbivory on Quercus muehlenbergii (Chinquapin Oak) with Carya laciniosa (Shellbark Hickory), a successfully regenerating tree species. Compared to hickory nuts, acorns were predated more, cached less, and dispersed shorter distances. Neither the distribution of the seedlings under the parent canopy nor browse damage differed between the 2 species. Our results suggest that seed-predation prevents regeneration of oaks in this endangered community. [ABSTRACT FROM AUTHOR]