Big maggots dig deeper: size-dependent larval dispersal in flies.

The ability of individual animals to select habitats optimal for development and survival can be constrained by the costs of moving through the environment. Animals that seek overwintering sites underground, for example, may be constrained by the energy required to burrow into the soil. We conducted field and laboratory studies to determine the relationship between individual size and overwintering site selection in the tephritid flies, Rhagoletis juglandis and Rhagoletis suavis. We also explored the effect of site selection on pupal mortality, parasitism, and the ability to emerge from overwintering sites after eclosion. In both species, and in both lab and field tests, larger pupae were found at deeper soil depths. In addition, marginally non-significant trends indicated pupae in deeper sites were 48% more likely to survive the overwintering period. Finally, larger individuals were more likely to eclose and emerge from the soil at a given depth, but flies in deep overwintering sites were less likely to emerge from those sites than flies in shallow sites. Our data indicate that overwintering site selection represents a trade-off between avoiding predators and parasites that occur at shallow sites, and the energetic and mortality costs of burrowing to, overwintering in, and emerging from, deeper sites. The size-dependent overwintering site selection demonstrated here has implications for population dynamics and pest control strategies. Some fly control measures, such as the introduction of parasites or predators, will be mitigated when the deepest and least accessible overwintering pupae represent a disproportionately large amount of the population's reproductive capacity.

Resource quality or competition: why increase resource acceptance in the presence of conspecifics?

Some animal species increase resource acceptance rates in the presence of conspecifics. Such responses may be adaptive if the presence of conspecifics is a reliable indicator of resource quality. Similarly, these responses could represent an adaptive reduction in choosiness under high levels of scramble competition. Although high resource quality and high levels of scramble competition should both favor increased resource acceptance, the contexts in which the increase occurs should differ. In this paper, we tested the effect of social environment on egg-laying and aggressive behavior in the walnut fly, Rhagoletis juglandis, in multiple contexts to determine whether increased resource acceptance in the presence of conspecifics was better viewed as a response to increased host quality or increased competition. We found that grouped females oviposit more readily than isolated females when provided small (low-quality) artificial hosts but not when provided large (high-quality) artificial hosts, indicating that conspecific presence reduces choosiness. Increased resource acceptance was observed even when exposure to conspecifics was temporally or spatially separate from exposure to the resource. Finally, we found that individuals showed reduced aggression after being housed in groups, as expected under high levels of scramble competition. These results indicate that the pattern of resource acceptance in the presence of conspecifics may be better viewed as a response to increased scramble competition rather than as a response to public information about resource quality.

Patterns of variation in the influence of natal experience on habitat choice.

The experience of animals in their natal or larval habitats has long been considered a potential source of variation in the habitat choices made later during dispersal. This idea has been of particular interest to evolutionary biologists because of the role such variation plays in the formation of host races and species. However, experiments that have tested for the effect of natal experience on habitat choice have produced widely variable results, leading to disagreement about the ecological importance of these effects. Here, I review the results of experiments within a broad range of animal taxa to assess the potential sources of variation in observed effects of natal experience on habitat choice. I provide a comprehensive summary of previous studies and demonstrate that when natal experience influences habitat choice, it nearly always increases the acceptance of the natal habitat type. Furthermore, I discuss mechanisms that allow natal experience to affect later habitat choice and describe how these mechanisms are influenced by various experimental design elements, such as the life stage at which early experience is provided to subjects. I conclude by reviewing the adaptive hypotheses for why animals might or might not respond to natal experience, and also how these hypotheses might explain interspecific differences in the importance of natal experience during habitat selection decisions. By understanding in what species, and in which contexts, experience influences habitat selection, we will be able to predict the ecological and evolutionary consequences of these effects more accurately.

4-Aryl-5-cyano-2-aminopyrimidines as VEGF-R2 inhibitors: synthesis and biological evaluation.

A novel series of 4-aryl-5-cyano-2-aminopyrimidines were synthesized and found to have potent VEGF-R2 kinase inhibitory activity. Structure-activity relationships were investigated and compound 14a was shown to be efficacious in a mouse model of corneal neovascularization.

Synthesis and biological study of 2-amino-4-aryl-5-chloropyrimidine analogues as inhibitors of VEGFR-2 and cyclin dependent kinase 1 (CDK1).

The series of 2-amino-4-aryl-5-chloropyrimidines was discovered to be potent for both VEGFR-2 and CDK1. Described here are the chemistry for analogue synthesis, SAR study, and its kinase selectivity prolifing. The full rat PK data and in vivo efficacy study are also included.

The effect of natal experience on habitat preferences.

Several important problems in ecology, evolution and conservation biology are affected by habitat selection in dispersing animals. Experience in the natal habitat has long been considered a potential source of variation in the habitat preferences displayed when dispersers select a post-dispersal habitat. However, the taxonomic breadth of this phenomenon is underappreciated, in part because partially overlapping, taxon-specific definitions in the literature have discouraged communication. Here, we explore the phenomenon of natal habitat preference induction (NHPI) and demonstrate that NHPI has been observed in a broad range of animal taxa. We consider the potential adaptive significance of NHPI, identify implications of its occurrence for problems in evolution, ecology and conservation biology, and encourage further study of this phenomenon.

The ecology of individuals: incidence and implications of individual specialization.

Most empirical and theoretical studies of resource use and population dynamics treat conspecific individuals as ecologically equivalent. This simplification is only justified if interindividual niche variation is rare, weak, or has a trivial effect on ecological processes. This article reviews the incidence, degree, causes, and implications of individual-level niche variation to challenge these simplifications. Evidence for individual specialization is available for 93 species distributed across a broad range of taxonomic groups. Although few studies have quantified the degree to which individuals are specialized relative to their population, between-individual variation can sometimes comprise the majority of the population's niche width. The degree of individual specialization varies widely among species and among populations, reflecting a diverse array of physiological, behavioral, and ecological mechanisms that can generate intrapopulation variation. Finally, individual specialization has potentially important ecological, evolutionary, and conservation implications. Theory suggests that niche variation facilitates frequency-dependent interactions that can profoundly affect the population's stability, the amount of intraspecific competition, fitness-function shapes, and the population's capacity to diversify and speciate rapidly. Our collection of case studies suggests that individual specialization is a widespread but underappreciated phenomenon that poses many important but unanswered questions.