Foraging decisions in nectarivores: unexpected interactions between flowerconstancy and energetic rewards

Citation
Psm. Hill et al., Foraging decisions in nectarivores: unexpected interactions between flowerconstancy and energetic rewards, ANIM BEHAV, 62, 2001, pp. 729-737
Citations number
50
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences","Neurosciences & Behavoir
Journal title
ANIMAL BEHAVIOUR
ISSN journal
0003-3472 → ACNP
Volume
62
Year of publication
2001
Part
4
Pages
729 - 737
Database
ISI
SICI code
0003-3472(200110)62:<729:FDINUI>2.0.ZU;2-O
Abstract
Foraging decisions are based on a suite of choices that include energetics and physiological constraints. Although travelling farther to harvest a gre ater net energetic reward is beneficial, many animals opt for a smaller net reward that requires less travel. Recent discoveries of a visual basis for flower constancy in the honeybee, Apis mellifera, led us to examine older reports that colour cues are superceded by energetic considerations. Here w e show that when individual bees foraged on pedicellate artificial flowers varying in colour and interfloral distance, their behaviour depended on the colours in the choice test. Colours of similar spectral reflectance (blue versus white), that would be clustered in the bee's visual colour space, el icited more visits to the closest flower when rewards were equal, but indiv iduals travelled a greater distance to harvest a higher energetic reward wh en reward quality varied. Bees chose the closest flower more often when rew ard volume decreased while quality remained constant. Yet, even when all fl owers were identical (morphology and reward), and only interfloral distance varied, bees did not always visit the closest flower. A dramatic differenc e was seen when the dimorphism was yellow-blue, colours quite separate in t he bee colour space and known to elicit constancy behaviour. Here, bees vis ited the closest flower only 5% of the time, and varying reward volume did not elicit different behaviour. Animals thus display differential foraging behaviour with respect to environmental cues that must be considered when a sking questions about other behavioural parameters. (C) 2001 The Associatio n for the Study of Animal Behaviour.