Movement uses resources that may otherwise be allocated to somatic maintenance or reproduction. How does increased energy expenditure affect resource allocation? Using the butterfly Speyeria mormonia, we tested whether experimentally increased flight affects fecundity, lifespan or flight capacity. W

Many specialist herbivores eat foods that are apparently low quality. The compensatory benefits of a poor diet may include protection from natural enemies. Several bee lineages specialize on pollen of the plant family Asteraceae, which is known to be a poor-quality food. Here we tested the hypothesi

Two interpretations are presented: (1) that partitioning searching time into discrete modes may enhance overaccuracy in invertebrates, as has been demonstrated previously for vertebrates and (2) that search dynamics of this type may explain some discrepancies between the predictions made by simple o

To explore mechanistic constraints on the evolution of optimal phenotypes, we develop an optimality model for thermoregulation in Colias butterflies. The model identifies the thermoregulatory characteristics of butterflies that maximize time available for flight activity subject to an overheating co

Mark-recapture data indicate that daily population sizes are low, most adults remain in residence at the colony only a few days, and there are age-specific sexual differences in movement, with older females perhaps leaving the colony site.

Bombus flavifrons utiliserait la densite de la plante butinee pour estimer le cout eventuel d'approvisionnement