Seasonality influences cuticle melanization and immune defense in a cricket: support for a temperature-dependent immune investment hypothesis in insects.

To improve thermoregulation in colder environments, insects are expected to darken their cuticles with melanin via the phenoloxidase cascade, a phenomenon predicted by the thermal melanin hypothesis. However, the phenoloxidase cascade also plays a significant role in insect immunity, leading to the additional hypothesis that the thermal environment indirectly shapes immune function via direct selection on cuticle color. Support for the latter hypothesis comes from the cricket Allonemobius socius, where cuticle darkness and immune-related phenoloxidase activity increase with latitude.

The role of gene flow asymmetry along an environmental gradient in constraining local adaptation and range expansion.

Theoretically, asymmetric gene flow along an environmental gradient can limit species range expansion by keeping peripheral populations from locally adapting. However, few empirical studies have examined this potentially fundamental evolutionary mechanism. We address this possibility in the cricket Allonemobius socius, which exist along a season-length gradient where the probability of producing a single generation per year (univoltinism) increases with latitude.

The accuracy of climate models' simulated season lengths and the effectiveness of grid scale correction factors.

Global climate change is expected to impact biological populations through a variety of mechanisms including increases in the length of their growing season. Climate models are useful tools for predicting how season length might change in the future. However, the accuracy of these models tends to be rather low at regional geographic scales.

Perceived sperm competition intensity influences seminal fluid protein production prior to courtship and mating.

Sperm competition is a potent postcopulatory selective force where sperm from rival males compete to fertilize a limited set of ova. Considering that sperm production is costly, we expect males to strategically allocate sperm in accordance with the level of competition. Accordingly, previous work has examined a male's strategic allocation in terms of sperm number.

Sex-specific variation in the emphasis, inducibility and timing of the post-mating immune response in Drosophila melanogaster.

Ecological immunology attempts to explain variation in immune function. Much of this work makes predictions about how potential hosts should invest in overall immunity. However, this 'overall' perspective under-emphasizes other critical aspects, such as the specificity, inducibility and timing of an immune response.

Patterns of phenotypic and genetic variation for the plasticity of diapause incidence.

Phenotypic plasticity describes an organism's ability to produce multiple phenotypes in direct response to its environmental conditions. Over the past 15 years empiricists have found that this plasticity frequently exhibits geographic variation and often possesses a significant heritable genetic basis. However, few studies have examined both of these aspects of plasticity simultaneously.

The evolutionary genetics of sexual size dimorphism in the cricket Allonemobius socius.

In recent years, investigations into the evolution of sexual size dimorphism have moved from a simple single trait, single sex perspective, to the more robust view of multivariate selection acting on both males and females. However, more accurate predictions regarding selection response may be possible if some knowledge of the underlying sex-specific genetic architecture exists. In the striped ground cricket, Allonemobius socius, females are the larger sex.

Post-mating disparity between potential and realized immune response in Drosophila melanogaster.

Reproductive costs are an essential component of evolutionary theory. For instance, an increase in reproduction is generally coupled with a decrease in immunocompetence shortly after mating. However, recent work in Drosophila melanogaster suggests that the potential to mount an immune response, as measured by the levels of immune gene expression, increases after mating.