The purpose of the present study was to determine whether temperature and hunger affect the decisions of whirligig beetles to group, and if so, how these two motivations are balanced.
- Whirligig beetles of the species Dineutes assimilis (Gyrinidae) live on the surface of small ponds, where they scavenge individually for food at night and aggregate in groups during the day.
Whirligig beetles have a number of well developed mechanisms for detecting and avoiding predators.
Fish appear to be the most common predator of whirligig beetles. Many species of fish have been documented to catch whirligig beetles including bluegill sunfish (Lepomis macrochirus), rainbow trout (Salmo gairdnerii), pumpkinseed sunfish (Lepomis gibbosus) and largemouth bass (Micropterus salmoides) (Benfield, 1972; Heinrich and Vogt, 1980).
Perhaps whirligig beetles are similar to water striders which have an upper and lower satiation threshold at which they exhibit territorial behavior (Wilcox and Ruckdeshel, 1982).
This seems doubtful, however, given the ability of whirligig beetles to avoid each other during their very rapid predator avoidance displays.
However, thermoregulation by increased activity level, seems unlikely in whirligig beetles because they are in close contact with cool water and have little apparent insulation.
Temperature and hunger levels are both important to whirligig beetles in their decision of whether or not to join a group.
Social behavior of adult whirligig beetles Dineutes nigrior and D.