Species differ in worker body size effects on critical thermal limits in seed-harvesting desert ants ( Messor ebeninus a
- PDF / 937,122 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 76 Downloads / 147 Views
Insectes Sociaux
RESEARCH ARTICLE
Species differ in worker body size effects on critical thermal limits in seed‑harvesting desert ants (Messor ebeninus and M. arenarius) S. O’Donnell1 · S. Bulova2 · V. Caponera1 · K. Oxman1 · I. Giladi3 Received: 30 May 2020 / Revised: 1 September 2020 / Accepted: 3 September 2020 © International Union for the Study of Social Insects (IUSSI) 2020
Abstract Extreme temperatures can constrain foraging behavior, and individual differences in thermal tolerances may affect foraging performance within and among species. Ambient temperatures may thus mediate competitive interactions among species that share resources. Different species of desert seed-harvesting ants (genus Messor) forage for similar food resources, and colonies can overlap in foraging areas. Because Messor species differ in body size distributions, and thermal tolerance is often size related in ants, we hypothesized that body size differences within and between Messor species would predict individual variation in worker thermal tolerances. Body size effects on thermal physiology could have implications for interspecific competition. We measured tolerances of extreme high (maximum critical temperature or CTmax) and low temperatures (CTmin) in two Messor species simultaneously at the same study site, smaller bodied M. ebeninus and larger bodied M. arenarius. Although the species did not differ significantly in CTmin or CTmax, tolerance of high temperatures was significantly size dependent for M. ebeninus: worker tolerances of high temperatures decreased with body size in this species. The patterns suggest the foraging activity of the smallest workers of smaller bodied species could be more constrained by high ambient temperatures, which could impact the division of labor within colonies as well as interspecific interactions. Keywords Ctmax · Ctmin · Polymorphic workers
Introduction Species differences in thermal physiology can affect interspecific ecological interactions. For example, when ambient temperatures approach or exceed a species’ thermal limits, that species may suffer decreased competitive ability relative to more thermally robust sympatric species. In some animal communities, species partition their activity periods Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00040-020-00782-5) contains supplementary material, which is available to authorized users. * S. O’Donnell [email protected] 1
Department of Biodiversity Earth and Environmental Science, Drexel University, Philadelphia, PA, USA
2
Department of Biology, Swarthmore College, Swarthmore, PA, USA
3
Mitrani Department of Desert Ecology, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben‑Gurion, 84990 Beersheba, Israel
depending on current thermal conditions (Cros et al. 1997; Kronfeld-Schor and Dayan 2003). The evolution of distinct species thermal physiologies is one mechanism that could favor species coexistence by reducing interspecific
Data Loading...
