How and why do nectar-foraging bumblebees initiate movements between inflorescences of wild bergamot Monarda fistulosa (Lamiaceae)?

By experimental manipulation of the nectar in flowers, I characterized the decision-making process used by nectar-gathering bumblebees for initiating movements between inflorescences of wild bergamot. The decision-making process has these characteristics: departure from an inflorescence is less likely as nectar rewards increase; departure decisions are based on the amount of nectar in the last flower probed and are not influenced by the nectar rewards in either the previously probed flower or the previously visited inflorescence; the number of flowers already probed at an inflorescence influences departure decisions weakly; a bees' response (to stay or to depart) to a given size of nectar reward is variable. Since previously proposed foraging rules do not accord with this description, I propose a new rule. I show by experiment that the movements made by bumblebees enhance foraging success.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47784/1/442_2004_Article_BF00319785.pd

THE COST OF REPRODUCTION AND EXPERIENCE-DEPENDENT VITAL RATES IN A SMALL PETREL

International audienceLife history theory predicts that higher levels of reproductive investment entail higher reproductive costs especially among young and inexperienced individuals that might not optimize reproductive investment. Using a long-term individual and state-dependent capture-recapture data on Storm Petrels (Hydrobates pelagicus) we analyzed whether breeding experience and current breeding investment were associated with the expression of the cost of reproduction in terms of reduced survival and/or future breeding performance. We found a positive relationship between current breeding investment, breeding experience, and future survival and an improvement in breeding performance with individual experience independently of the previous breeding outcome. Our results suggest that the survival cost paid by first-time breeders and the positive correlation between reproduction and survival corresponds to selection against low quality birds unrelated to the breeding effort. Our work outlines the need to investigate the effect of multiple individual traits on different life history trade-offs simultaneously