Life table of Chilo suppressalis (Lep.: Crambidae) reared on rice seedlings: effects of individual and group rearing
عنوان دوره: دومین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
Rice striped stem borer (SSB), Chilo suppressalis (Lep. Crambidae), among the rice pests dominantly appears in the south Caspian basin. The aim of this study was to evaluate individual- and group-reared demography of the borer on a local rice variety, Tarom Hashemi. Individual-reared experiments (I) were conducted in glass tubes (18 × 1.5 cm, h × d) containing a rice seedling as food. For group-reared experiments 500 ml jars (10 × 8 cm, h × d) with rice seedlings were used. Groups of 20 (GI) and or 30 (GII) neonate larvae were then transmitted on the seedlings. During the larval development seedlings were replaced and jars and tubes were changed as needed. Upon pupae appearance, they were separately kept till adult eclusion. Pairs of adult males and females were separately confined in 8.8 l plastic containers for egg laying. Pupae and adults appearance and laid eggs were daily recorded. All experiments carried out in a growth chamber with T = 25 ± 1ºC, 65-75% RH and a 16:8 L:D photoperiod. Data were analyzed using age-stage, two-sex life table software. Intrinsic rates of increase were 0.0397, 0.0367 and 0.055 day-1 for GI, GII and I, respectively. Respective finite rates of increase were 1.0405, 1.0374 and 1.057 day-1. Net reproductive rates were 9.28, 7.95 and 21.07 (offspring/individual) for the respective treatments. In general, laboratory rearing of SSB on a local rice variety successfully was carried out either in group or individual experiments. Demographic parameters were higher in individual trial compared with those in groups.
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