Preferred temperatures of desert honey ants (hymenoptera: formicidae)

1. 1.Preferred temperature ranges were determined for workers of 5 species of Myrmecocystus in a temperature gradient on wet sand.

2. 2.Workers of the diurnally foraging species, M. mendax Wheeler, M romainei Cole, M. depilis Forel, and M. mimicus Wheeler, were distributed between 7 and 45°C, and workers of one nocturnal species, M. mexicanus Wesmael, were distributed between 5 and 35°C.

3. 3.Mean preferred temperatures of the 5 species increased as follows: mexicanus < mendax < romainei < depilis < mimicus.

4. 4.Preferred temperatures of M. romainei and M. mexicanus were higher in the summer than in the fall.

5. 5.After 2 h in the gradient on dry sand, workers of M. romainei were distributed similarly to those on wet sand, but after 8 h on dry sand, most workers were below 12°C where the air was saturated.

Author Keywords: Myrmecocystus romainei; Myrmecocystus depilis; Myrmecocystus mimicus; Myrmecocystus mendax; Myrmecocystus mexicanus; honey ants: preferred temperatures; temperature limits; desert adaptations: humidity responses