AbstractDaily periods of activity of eight colonies of the eastern tent caterpillar, Malacosoma americanum (F.), were monitored photoelectronically under a simulated springtime photoperiod in the laboratory. Colonies averaged 3.7 ± 0.1 (S.E.) activity periods per day (N = 103 colony-days), separated by an average interval of 6.6 ± 0.1 h (N = 389). Foraging trips lasted an average 2.8 ± 0.1 h (N = 397). A plot of 336 activity period midpoints (seven colonies) showed all colony activity peaks to occur between 0600 and 0800 h, 1100 and 1600 h, 1900 and 2100 h, and 0100 and 0400 h. The first three peaks correspond well to previously reported field observations but the early morning foraging trip, which occurred in darkness, was previously unreported by field investigators. The temporal placement of activity peaks shifted from day to day within colonies but the occurrence of evening foraging trips was the most consistent. Dark onset appeared to trigger foraging in resting colonies. Recruitment of hungry caterpillars to food finds appears to be a common component of the foraging strategy of this species.
