Patterns of pollen and nectar foraging specialization by bumblebees over multiple timescales using RFID.
The ecological success of social insects is frequently ascribed to improvements in task performance due to division of labour amongst workers. While much research has focused on improvements associated with lifetime task specialization, members of colonies can specialize on a given task over shorter time periods. Eusocial bees in particular must collect pollen and nectar rewards to survive, but most workers appear to mix collection of both rewards over their lifetimes. We asked whether bumblebees specialize over timescales shorter than their lifetime. We also explored factors that govern such patterns, and asked whether reward specialists made more foraging bouts than generalists. In particular, we described antennal morphology and size of all foragers in a single colony and related these factors to each forager's complete foraging history, obtained using radio frequency identification (RFID). Only a small proportion of foragers were lifetime specialists; nevertheless, >50% of foragers specialized daily on a given reward. Contrary to expectations, daily and lifetime reward specialists were not better foragers (being neither larger nor making more bouts); larger bees with more antennal olfactory sensilla made more bouts, but were not more specialized. We discuss causes and functions of short and long-term patterns of specialization for bumblebee colonies.
Graduate Interdisciplinary Program in Entomology and Insect Science, University of Arizona, Tucson, AZ, 85721, USA.
Avery L
AL
Russell
Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, 85721, USA.
Sarah J
SJ
Morrison
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA.
Eleni H
EH
Moschonas
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA.
Daniel R
DR
Papaj
D000818:Animals; D001516:Bees / Q000033:anatomy & histology / Q000502:physiology / Q000648:ultrastructure; D005247:Feeding Behavior; D057048:Plant Nectar; D011058:Pollen; D057233:Radio Frequency Identification Device
D057048:Plant Nectar