Behavioral Ecology and Sociobiology

, Volume 66, Issue 6, pp 879–889

Vortex formation and foraging in polyphenic spadefoot toad tadpoles

  • Sepideh Bazazi
  • Karin S. Pfennig
  • Nils Olav Handegard
  • Iain D. Couzin
Original Paper

DOI: 10.1007/s00265-012-1336-1

Cite this article as:
Bazazi, S., Pfennig, K.S., Handegard, N.O. et al. Behav Ecol Sociobiol (2012) 66: 879. doi:10.1007/s00265-012-1336-1

Abstract

Animal aggregations are widespread in nature and can exhibit complex emergent properties not found at an individual level. We investigate one such example here, collective vortex formation by congeneric spadefoot toad tadpoles: Spea bombifrons and Spea multiplicata. Tadpoles of these species develop into either an omnivorous or a carnivorous (cannibalistic) morph depending on diet. Previous studies show that S. multiplicata are more likely to develop into omnivores and feed on suspended organic matter in the water body. The omnivorous morph is frequently social, forming aggregates that move and forage together and form vortices in which they adopt a distinctive slowly rotating circular formation. This behaviour has been speculated to act as a means to agitate the substratum in ponds and thus could be a collective foraging strategy. Here we perform a quantitative investigation of the behaviour of tadpoles within aggregates. We found that only S. multiplicata groups exhibited vortex formation, suggesting that social interactions differ between species. The probability of collectively forming a vortex, in response to introduced food particles, increased for higher tadpole densities and when tadpoles were hungry. Individuals inside a vortex moved faster and exhibited higher (by approximately 27%) tailbeat frequencies than those outside the vortex, thus incurring a personal energetic cost. The resulting environmental modification, however, suggests that vortex behaviour may be an adaptation to actively create and exploit a resource patch within the environment.

Keywords

Collective behaviour Tadpoles Social foraging Vortices 

Supplementary material

265_2012_1336_MOESM1_ESM.doc (46 kb)
ESM 1(DOC 46.0 kb)

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Sepideh Bazazi
    • 1
  • Karin S. Pfennig
    • 2
  • Nils Olav Handegard
    • 3
  • Iain D. Couzin
    • 4
  1. 1.Department of ZoologyUniversity of OxfordOxfordUK
  2. 2.Department of BiologyUniversity of North CarolinaChapel HillUSA
  3. 3.Institute of Marine ResearchNordnesNorway
  4. 4.Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonUSA

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