Body size varies considerably among species and among populations within species, exhibiting many repeatable patterns. However, which sources of selection generate geographic patterns, and which components of fitness mediate evolution of body size, are not well understood. For many animals, resource quality and intraspecific competition may mediate selection on body size producing large-scale g...

Most studies of insect dietary evolution su€er from limited information on the history of host use patterns; historical patterns can only be inferred from modern patterns. We examine the ecology of a recent diet breadth expansion onto an introduced host by the seed beetle, Stator limbatus, to (1) determine if pre-existing variation for survival on Chloroleucon ebano is present in natural popula...

Inbreeding depression is well documented in insects but the degree to which inbreeding depression varies among populations within species, and among traits within populations, is poorly studied in insects other than Drosophila. Inbreeding depression was examined in two long-term laboratory colonies of the seed beetle, Callosobruchus maculatus (Fabricius), which are used frequently as models for...

Inbreeding depression has been documented in many insect species, but the degree to which it varies among traits within populations and among populations within species is poorly understood. We used a single-generation factorial breeding design to examine variation in inbreeding depression among three populations of the seed-feeding beetle, Stator limbatus Horn (Coleoptera: Chrysomelidae: Bruch...

We examine the inbreeding load for adult life span and mortality rates of two seed beetle species, Callosobruchus maculatus and Stator limbatus. Inbreeding load differs substantially between males and females in both study populations of C. maculatus--life span of inbred females was 9-13% shorter than the life span of outbred females, whereas the life span of inbred males did not differ from th...

1. In most animals, females live longer than males, and large individuals live longer than small individuals. We examine both gender and body size effects on adult lifespan in two species of seed beetles ( Callosobruchus maculatus and Stator limbatus ), and test whether body size differences between males and females can explain genderdifferences in mortality rates and lifespan. 2. In both spec...

Seeds of many arid habitat plants have a water-impermeable coat and can germinate only after being scarified. Bruchine seed beetles are important parasites of legume seeds in these environments, but their effect on germination can be unpredictable. Beetles deplete seed resources and can kill the embryo but also scarify seeds. We investigated the effects of a generalist parasite, Stator limbatus...

Plants can vary substantially among species in morphological and physiological traits that influence their resistance to herbivores and their quality for herbivore growth and development. Seeds of the desert trees Cercidium floridum and C. microphyllum vary within and among populations in their resistance to, and suitability for, growth and development of larvae of the seed beetle, Stator limba...

The role of temperature is central to both organic evolution and ecological processes. However, how temperature affects selection on body size is unknown. We tested whether small seed beetles (Stator limbatus) have an advantage over large beetles during scramble competition for mates, and whether this advantage varies with temperature. Within lines of beetles artificially selected to be large v...

Variation in body size, growth and life history traits of ectotherms along latitudinal and altitudinal clines is generally assumed to represent adaptation to local environmental conditions, especially adaptation to temperature. However, the degree to which variation along these clines is due to adaptation vs plasticity remains poorly understood. In addition, geographic patterns often differ bet...