Different response in respiration between predaceous and phytophagous lady beetles (Coleoptera: Coccinellidae) to starvation

Abstract

SummarySurvival times and changes in the respiratory rates and the live body weights of a predaceous lady beetle, Coccinella septempunctata bruckiiMulsant, and a phytophagous lady beetle, Henosepilachna vigintioctopunctataFabricius, under starved conditions were compared. Females of C. septempunctata survived for a long time, 91.4±27.2 days, under starved conditions. On the other hand, males of C. septempunctata and males and females of H. vigintioctopunctata survived for 31.3±10.2, 17.6±6.0 and 22.9±5.3 days, respectively. These values were much shorter than that of C. septempunctata females. The respiratory rate of starved C. septempunctata increased on the first day of starvation, but hereafter rapidly decrased till the fourth day, keeping an almost constant level thereafter. On the tenth day of starvation, the respiratory rates of C. septempunctata were 56.4% in males and 58.5% in females of initial values. The respiratory rate of males was 1.47 to 2.14 times as high as that of females, and there were significant differences between the two. Males and females of C. septempunctata lost their body weights by 20.2% and 17.8% of initial weights, respectively, during the first ten days of starvation. The respiratory rate of starved H. vigintioctopunctata did not significantly change till the fourth day of starvation, and thereafter decreased slowly. On the tenth day of starvation, the respiratory rates of H. vigintioctopunctata were 70.3% in males and 74.8% in females of initial values. These values were much higher than those of C. septempunctata. Males and females of H. vigintioctopunctata lost their body weights by 22.4% and 25.4% of initial weights, respectively, during the first ten days of starvation. Thus under starvation H. vigintioctopunctata underwent the larger weight loss than C. septempunctata. Differences in strategies against starvation between poikilothermal predators and herbivores and their roles in population dynamics were discussed.