, Volume 183, Issue 4, pp 1007–1017

Thermal constraints on foraging of tropical canopy ants

  • Michelle Elise Spicer
  • Alyssa Y. Stark
  • Benjamin J. Adams
  • Riley Kneale
  • Michael Kaspari
  • Stephen P. Yanoviak
Behavioral ecology – original research

DOI: 10.1007/s00442-017-3825-4

Cite this article as:
Spicer, M.E., Stark, A.Y., Adams, B.J. et al. Oecologia (2017) 183: 1007. doi:10.1007/s00442-017-3825-4


Small cursorial ectotherms risk overheating when foraging in the tropical forest canopy, where the surfaces of unshaded tree branches commonly exceed 50 °C. We quantified the heating and subsequent cooling rates of 11 common canopy ant species from Panama and tested the hypothesis that ant workers stop foraging at temperatures consistent with the prevention of overheating. We created hot experimental “sunflecks” on existing foraging trails of four ant species from different clades and spanning a broad range of body size, heating rate, and critical thermal maxima (CTmax). Different ant species exhibited very different heating rates in the lab, and these differences did not follow trends predicted by body size alone. Experiments with ant models showed that heating rates are strongly affected by color in addition to body size. Foraging workers of all species showed strong responses to heating and consistently abandoned focal sites between 36 and 44 °C. Atta colombica and Azteca trigona workers resumed foraging shortly after heat was removed, but Cephalotes atratus and Dolichoderus bispinosus workers continued to avoid the heated patch even after >5 min of cooling. Large foraging ants (C. atratus) responded slowly to developing thermal extremes, whereas small ants (A. trigona) evacuated sunflecks relatively quickly, and at lower estimated body temperatures than when revisiting previously heated patches. The results of this study provide the first field-based insight into how foraging ants respond behaviorally to the heterogeneous thermal landscape of the tropical forest canopy.


Arboreal Behavior Formicidae Panama Sunfleck 

Supplementary material

442_2017_3825_MOESM1_ESM.xlsx (26 kb)
Supplementary material 1 (XLSX 26 kb)
442_2017_3825_MOESM2_ESM.pdf (93 kb)
Supplementary material 2 (PDF 93 kb)

Funding information

Funder NameGrant NumberFunding Note
National Science Foundation
  • DEB-1252614
  • DEB-0842038, EF-1065844

Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  1. 1.Department of Biological SciencesUniversity of PittsburghPittsburghUSA
  2. 2.Department of BiologyUniversity of LouisvilleLouisvilleUSA
  3. 3.Department of BiologyUniversity of OklahomaNormanUSA
  4. 4.Smithsonian Tropical Research InstituteBalboaRepublic of Panama

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