Nymphal development and survival of Macrolophus pygmaeus Rambur (Hemiptera: Miridae) on two eggplant varieties as affected by temperature and presence/absence of prey

Nymphal development of the predator Macrolophus pygmaeus Rambur (Hemiptera: Miridae) was investigated on two eggplant varieties, Bonica and Black Beau ty, in an attempt to identify the possible role that plant variety plays in the development and survival of the predator and to determine whether thes e biological characteristics are influenced by temperature and prey. The de velopment of nymphs was studied in the presence and absence of the prey, My zus persicae (Sulzer), at 15, 20, 25, 30, and 35 degreesC, 65 +/- 5% RH, an d 16:8 h (L:D) photoperiod. Significant differences in the periods of nymph al development were evident in the two varieties at 15 degreesC when IM. pe rsicae was offered as prey, and at 15 and 30 degreesC, when there was no pr ey, significantly shorter periods of development were recorded on Bonica th an on Black Beauty. Mortality rates of the nymphs were similar in the prese nce of prey on both varieties but, in the absence of prey, higher mortality rates were recorded on Black Beauty than on Bonica. In both presence and a bsence of prey, at 35 degreesC, a small number of nymphs reached adulthood on Bonica, whereas no nymphs did so on Black Beauty. Therefore, the less su itable variety, Black Beauty, had a significant effect on the development a nd survival of nymphs of this predator, mainly in the absence of prey and a t lower and higher temperatures. It is concluded that the selection of a su itable variety for the development and survival of M. pygmaeus, particularl y in the absence of prey, could improve the efficiency of a biological cont rol program in which this predator is going to be used. This is of particul ar importance for its establishment and effectiveness at the beginning of t he growing season when temperature is relatively low and the prey is absent or scarce, as well as in summer when temperatures are high enough (around 30 degreesC or even higher). (C) 2001 Academic Press.