Fecundity of Thanasimus dubius (Coleoptera: Cleridae) Rebounds after a Period of Prey Scarcity

We field-collected Thanasimus dubius (Fabricius) (Coleoptera: Cleridae) adults during spring, maintained them separately in the laboratory, and initially gave them four bark beetle adults [Ips grandicollis (Eichhoff) or Tomicus piniperda (L.) (Coleoptera: Curculionidae: Scolytinae)] daily as prey. Using a subset of the female clerids (N = 41), we assigned them to one of four feeding groups that varied in the number of prey provided daily. For the first four weeks of a 12–week study, the four diets were: four prey daily, two prey daily, one prey daily, and one prey every 2 days. After four weeks, all females were again given four prey daily until their death or to the end of the study. During the initial 4–week treatment period, females provided four prey daily laid the most eggs on average (106 eggs per female over four weeks). Average egg production by females provided two prey daily (63) or one prey daily (25) were intermediate, while females given one prey every two days laid the fewest eggs (10). Starting in week 5, when all females were given four prey daily, egg production by females that had been on the two most restricted diets matched the other two groups and surpassed them by week 6. At the end of 12 weeks, overall female longevity and fecundity did not differ significantly among the four feeding groups.