تغییر پارامترهای جدول زندگی شته سیاه باقلا Aphis fabae Scopoli ، در پاسخ به پارازیتیسم مادری

Maternal parasitism is expected to affect fitness components of progeny so that maternal effects effectively protect offspring from environmental stressors. This study constructed life tables for black bean aphids, Aphis fabae Scopoli (Hemiptera: Aphididae), born of mothers which were parasitized in the third instar by Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae, Aphidiinae), in order to compare them to those born of unparasitized mothers. A series of third instar aphids (n = 40 per treatment) were exposed to either one or five mated, two-day-old L. fabarum females for 24 h to produce singly parasitized and superparasitized mothers, respectively. After the wasps were removed, the aphids from each treatment (n = 35) were each isolated in a glass Petri dish on a broad bean leaf at 21 ± 1°C, 65–75% RH, and a 16:8 (L:D) photoperiod, to complete development. Once aphids molted to the adult stage, the nymphs produced by each were counted and removed daily. The results indicated that maternal parasitism decreased the intrinsic rate of natural increase (rm) in the superparasitism treatment (0.296 ± 0.002) relative to that of the singly parasitized (0.394 ± 0.007) or control treatments (0.590 ± 0.001). Similarly, the net reproductive rate (R0), and the finite rate of increase (ʎ) were both decreased as a consequence of maternal parasitism, relative to controls, while growth time (GT) increased, the differences being greater when mothers were superparasitized. Our results revealed that maternal parasitism exacts a fitness cost for surviving progeny, probably arising from a stress response to parasitoid teratocytes as they mount a physiological assault on developing embryos.