Bumblebee response thresholds and body size: does worker diversity increase colony performance?

Jennifer M. Jandt, Anna Dornhaus

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Although models of colony organization in social insects often rely on the assumption that within-group variation increases group performance, empirical support for this is mostly confined to studies of genetic variation. However, workers in ant or bee colonies often vary in behaviour and morphology even when genetic variation is low. Bumblebees provide a unique opportunity to explore the consequences of such variation: colonies have a wide range of worker body sizes compared to other social bee species, and workers also vary in response thresholds (i.e. stimulus levels at which workers respond by performing a task), in spite of queens being singly mated (and thus, low genetic variation). Here we test how body size and response threshold diversity affect colony performance in two unrelated in-nest tasks (thermoregulation and undertaking). We manipulated worker diversity using worker removals to restrict threshold or body size variation within the colony. We also quantified the degree of intracolony variation across colonies and related this to colony performance. In general, colonies took longer to cool the nest after bees were removed, but there was no significant effect of treatment on fanning or undertaking success. Furthermore, when intracolony variation was analysed as a continuous variable, we found no effect on colony-level thermoregulation or undertaking performance. Instead, average threshold was a more useful predictor of thermoregulation success, and colonies with a narrower range of size variation had more success at undertaking. These results emphasize the importance of understanding how different types of variation (e.g. behavioural, morphological, etc.) contribute to colony performance.

Original languageEnglish (US)
JournalAnimal Behaviour
DOIs
StateAccepted/In press - 2013

Fingerprint

Bombus
thermoregulation
body size
genetic variation
Apoidea
nests
worker bees
social insects
queen insects
bee
nest
testing
social insect
ant

Keywords

  • Bombus impatiens
  • bumblebee
  • collective behaviour
  • division of labour
  • intracolony variation
  • thermoregulation
  • undertaking

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology

Cite this

Bumblebee response thresholds and body size : does worker diversity increase colony performance? / Jandt, Jennifer M.; Dornhaus, Anna.

In: Animal Behaviour, 2013.

Research output: Contribution to journalArticle

@article{a5c4e5c4c6e94e8cbabddab1bc108eec,
title = "Bumblebee response thresholds and body size: does worker diversity increase colony performance?",
abstract = "Although models of colony organization in social insects often rely on the assumption that within-group variation increases group performance, empirical support for this is mostly confined to studies of genetic variation. However, workers in ant or bee colonies often vary in behaviour and morphology even when genetic variation is low. Bumblebees provide a unique opportunity to explore the consequences of such variation: colonies have a wide range of worker body sizes compared to other social bee species, and workers also vary in response thresholds (i.e. stimulus levels at which workers respond by performing a task), in spite of queens being singly mated (and thus, low genetic variation). Here we test how body size and response threshold diversity affect colony performance in two unrelated in-nest tasks (thermoregulation and undertaking). We manipulated worker diversity using worker removals to restrict threshold or body size variation within the colony. We also quantified the degree of intracolony variation across colonies and related this to colony performance. In general, colonies took longer to cool the nest after bees were removed, but there was no significant effect of treatment on fanning or undertaking success. Furthermore, when intracolony variation was analysed as a continuous variable, we found no effect on colony-level thermoregulation or undertaking performance. Instead, average threshold was a more useful predictor of thermoregulation success, and colonies with a narrower range of size variation had more success at undertaking. These results emphasize the importance of understanding how different types of variation (e.g. behavioural, morphological, etc.) contribute to colony performance.",
keywords = "Bombus impatiens, bumblebee, collective behaviour, division of labour, intracolony variation, thermoregulation, undertaking",
author = "Jandt, {Jennifer M.} and Anna Dornhaus",
year = "2013",
doi = "10.1016/j.anbehav.2013.10.017",
language = "English (US)",
journal = "Animal Behaviour",
issn = "0003-3472",
publisher = "Academic Press Inc.",

}

TY - JOUR

T1 - Bumblebee response thresholds and body size

T2 - does worker diversity increase colony performance?

AU - Jandt, Jennifer M.

AU - Dornhaus, Anna

PY - 2013

Y1 - 2013

N2 - Although models of colony organization in social insects often rely on the assumption that within-group variation increases group performance, empirical support for this is mostly confined to studies of genetic variation. However, workers in ant or bee colonies often vary in behaviour and morphology even when genetic variation is low. Bumblebees provide a unique opportunity to explore the consequences of such variation: colonies have a wide range of worker body sizes compared to other social bee species, and workers also vary in response thresholds (i.e. stimulus levels at which workers respond by performing a task), in spite of queens being singly mated (and thus, low genetic variation). Here we test how body size and response threshold diversity affect colony performance in two unrelated in-nest tasks (thermoregulation and undertaking). We manipulated worker diversity using worker removals to restrict threshold or body size variation within the colony. We also quantified the degree of intracolony variation across colonies and related this to colony performance. In general, colonies took longer to cool the nest after bees were removed, but there was no significant effect of treatment on fanning or undertaking success. Furthermore, when intracolony variation was analysed as a continuous variable, we found no effect on colony-level thermoregulation or undertaking performance. Instead, average threshold was a more useful predictor of thermoregulation success, and colonies with a narrower range of size variation had more success at undertaking. These results emphasize the importance of understanding how different types of variation (e.g. behavioural, morphological, etc.) contribute to colony performance.

AB - Although models of colony organization in social insects often rely on the assumption that within-group variation increases group performance, empirical support for this is mostly confined to studies of genetic variation. However, workers in ant or bee colonies often vary in behaviour and morphology even when genetic variation is low. Bumblebees provide a unique opportunity to explore the consequences of such variation: colonies have a wide range of worker body sizes compared to other social bee species, and workers also vary in response thresholds (i.e. stimulus levels at which workers respond by performing a task), in spite of queens being singly mated (and thus, low genetic variation). Here we test how body size and response threshold diversity affect colony performance in two unrelated in-nest tasks (thermoregulation and undertaking). We manipulated worker diversity using worker removals to restrict threshold or body size variation within the colony. We also quantified the degree of intracolony variation across colonies and related this to colony performance. In general, colonies took longer to cool the nest after bees were removed, but there was no significant effect of treatment on fanning or undertaking success. Furthermore, when intracolony variation was analysed as a continuous variable, we found no effect on colony-level thermoregulation or undertaking performance. Instead, average threshold was a more useful predictor of thermoregulation success, and colonies with a narrower range of size variation had more success at undertaking. These results emphasize the importance of understanding how different types of variation (e.g. behavioural, morphological, etc.) contribute to colony performance.

KW - Bombus impatiens

KW - bumblebee

KW - collective behaviour

KW - division of labour

KW - intracolony variation

KW - thermoregulation

KW - undertaking

UR - http://www.scopus.com/inward/record.url?scp=84887264981&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84887264981&partnerID=8YFLogxK

U2 - 10.1016/j.anbehav.2013.10.017

DO - 10.1016/j.anbehav.2013.10.017

M3 - Article

AN - SCOPUS:84887264981

JO - Animal Behaviour

JF - Animal Behaviour

SN - 0003-3472

ER -