Interaction between life history parameters of Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) with physical and biochemical properties of legumes species

The cowpea beetle, Callosobruchus maculatus, is a highly damaging and destructive pest of pulse seeds, which is widely distributed in tropical and subtropical areas. In this research, the effects of the seeds of six pulse species (broad bean, cowpea, lentil, green gram, chickpea, and soybean) were assessed on life history and energy content of C. maculatus under controlled conditions, 27 +/- 2 degrees C, 60 +/- 5% relative humidity, and a photoperiod of 10:14 (L:D) h. Some biochemical (protein, starch, phenol, total anthocyanin, flavonoids and condensed tannin contents) and physical (humidity, seed volume and area) characteristics of legume seeds were measured and their interactions with population growth parameters of C. maculatus were assessed. The results showed that biological properties of C. maculatus were significantly different when fed on various legume seeds. The developmental time of cowpea beetle fed on broad bean (32.08 day) was longer compared with other seeds. The lowest immature survival rate was observed on broad bean. The pupal weight on cowpea, chickpea and green gram was significantly higher than on broad bean and lentil seeds. The lowest intrinsic rate of population increase (r) and net reproductive rate (R-0) were recorded on soybean (r = 0.055 d(-1), R-0 = 14.02 offspring). The intrinsic rate of increase and the finite rate of increase (lambda) of C. maculatus reared on cowpea (r = 0.145 d(-1), lambda = 1.16 d(-1)) and green gram (r = 0.144 d(-1), lambda = 1.15 d(-1)) seeds were significantly higher than those reared on other legumes. Significant correlations were detected between life history parameters of C. maculatus with biochemical and physical traits of legume seeds. The results showed that cowpea and green gram were relatively susceptible legume seeds and that soybean was a relatively resistant host for feeding of C. maculatus, which can be useful in the development or improvement of IPM programs for C. maculatus.