Behavioral Ecology and Sociobiology

, Volume 47, Issue 5, pp 346–352

The effect of queen-worker conflict on caste determination in the bumblebee Bombus terrestris

  • J. Cnaani
  • G. E. Robinson
  • G. Bloch
  • D. Borst
  • A. Hefetz
Original Article

DOI: 10.1007/s002650050675

Cite this article as:
Cnaani, J., Robinson, G., Bloch, G. et al. Behav Ecol Sociobiol (2000) 47: 346. doi:10.1007/s002650050675

Abstract 

Endocrine analyses were used to investigate the well-known association between queen production and the onset of worker reproduction (termed the competition phase, CPh) in Bombus terrestris. Larvae that reached the age of 5 days before the CPh had a worker-like profile: low juvenile hormone (JH) biosynthesis rates and low JH hemolymph titers. In contrast, larvae that reached the age of 5 days during the CPh had a queen-like profile: high JH biosynthesis rates and high hemolymph JH levels. Larval fate could be manipulated by transplanting egg cells into host colonies with different social structures. There was a steep rise in JH production in larvae transplanted into colonies near or during the CPh. This indicates that during colony development, larvae switch from the ”worker developmental pathway” to the ”queen developmental pathway,” and that the switch is socially regulated. In small rearing groups, larvae reared with queens before the CPh developed into workers, whereas those reared with queens after the CPh developed into queens. Variation in worker type (naive or experienced) did not affect caste determination. Therefore, we hypothesize that queens produce a pheromone that directly inhibits queen differentiation by larvae. We also present two alternative scenarios that explain the timing of gyne production in B. terrestris, one based on ecological constraints and the other based on queen-worker competition.

Key words BumblebeesBombus terrestrisCaste determinationQueen-worker conflictJuvenile hormone

Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • J. Cnaani
    • 1
  • G. E. Robinson
    • 2
  • G. Bloch
    • 2
  • D. Borst
    • 3
  • A. Hefetz
    • 1
  1. 1.Department of Zoology, Tel Aviv University, Ramat Aviv 69978, Israel e-mail: hefetz@post.tau.ac.il Tel.: +972-3-6409341, Fax: +972-3-6406991IL
  2. 2.Department of Entomology, University of Illinois, 320 Morrill Hall, Urbana, IL 61801, USAUS
  3. 3.Department of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USAUS