Developmental parameters of Opisina arenosella Walker (Lepidoptera: Oecophoridae) on alternative host plants

Survival and development of Opisina arenosella Walker (Lepidoptera: Oecophoridae), the leaf eating caterpillar of coconut, were studied on three host plants on which comparatively high feeding rates were observed: Artocarpus heterophyllus Lam. (Jack fruit), Elaeis guineensis Jacq. (Oil palm) and Anacardium occidentale L. (Cashew), plus coconut palm (Cocos nucifera L.). A freshly hatched first instar O. arenosella larva was transferred onto the leaf in a glass beaker and reared on them. Fresh leaves were provided every 48 h until pupation of O. arenosella larvae. The larval period, pupal period and the longevity of the successfully developing adult female moths were recorded. For each plant species, there were ten replicates yielding adult moths. Data on the length of O. arenosella developmental stages and adult longevity had homogenous variance (Bartlett’s test on residuals from ANOVA of developmental time across plant species: Larval period, v2 = 5.13, df = 3, P = 0.163; Pupal period, v2 = 0.15, df = 3, P = 0.986; Longevity, v2 = 1.58, df = 3, P = 0.664) and were normally distributed (Shapiro–Wilk test: Larval period, W = 0.978, P = 0.632; Pupal period, W = 0.981, P = 0.714; Longevity, W = 0.974, P = 0.472). Thus, the effects of plant species on each of these measures were tested using one-way ANOVA in GenStat. Aggregation of factor levels was used to evaluate differences between treatments when overall results were significant (Crawley 1993). The larval period differed significantly across all four plant species presented and was shortest when on coconut. Pupal periods were also shortest on coconut but did not differ among larvae fed on the three intercrops. The longevity of adult females was unaffected by the species of plant on which larvae had fed.