Muhammad & Ande: Biotic decimating factors affecting the distribution of Cirina forda population 57 West African Journal of Applied Ecology, vol. 22(2), 2014: 57–68. Biotic Decimating Factors Affecting the Distribution of Cirina forda Westwood (Lepidoptera: Saturniidae ) Population in Niger State, Nigeria M. I. Muhammad 1 and A. T. Ande 2 1 Department of Basic Sciences, College of Agriculture, P.M.B, 109, Mokwa, Niger State 2 Department of Zoology, University of Ilorin, Kwara State, Nigeria Corresponding author; Email: masudmohdizom@yahoo.com Abstract The biotic agents, i.e. predators, parasites and pathogens that could be responsible for the mysterious occurrence and decimation of C. forda (Westwood) in Niger State, Nigeria, were monitored, identified, and their individual interactive effects reported from farm lands and villages from six local government areas, namely Katcha, Paikoro, Gurara, Lavun, Lapai and Rafi. All the developmental stages, i.e. eggs, larva, pupa and adult of C. forda had a biotic agent affecting them. The checklist of the agents include Anastatus spp, an egg parasitoid; larval predator including Ocecophyla longinoda; Spiders, and black crow bird; larval pathogens of viral origin, i.e. Nuclear polyhedrosis virus and Granulosis virus and of fungal origin i.e. Nomerae arileyi and Beauveria bassiana; a pupalparasitoid, Hockeria spp;and Agama lizard, a predator of imago stage. The possible roles of each of these agents in the ephemeral nature and beliefs about the mysterious distribution of C. forda were substantiated and discussed. Introdution The emperor moth, Cirina forda Westwood (Lepidoptera: Saturniidae) caterpillar, is one of the most popular edible food insects in Nigeria (Fasoranti & Ajiboye, 1983; Ande, 1991; Ande & Fasoranti, 1995). Like all other Lepidopterans, C. forda is holometabolous (Ande & Fasoramti, 1996, 1997). It is typically an African moth whose sole host is the shea butter tree, Vittelaria paradoxa (Ande,1991; Ande & Fasoranti, 1996). C. forda distribution coincides with the occurrence of V. paradoxa in Nigeria with Niger State featuring very prominently (Ande, 1991). C. forda is a univoltine insect whose caterpillar, i.e. the most conspicuous developmental stage, are noticed between June and September annually (Ande & Fsaoranti, 1997). The caterpillars defoliate matured fruiting-bearing trees, thus, causing extensive damage to V. paradoxa trees (Greenwood, 1929) such that 90% of the trees’ leafy area is damaged in a season (Owusu-Manu & Kuma, 1990). Unfortunately the period of this caterpillar attack coincides with the period of seed maturation and ripening of V. paradoxa fruits (Ande & Fasoranti, 1995). The occurrence and distribution of this insect remains a mystery as they are generally regarded as ephemeral. Even locations that are renowned for their presence, when they are in season, frequently come up with no harvest or very low yield even in contiguous harvest seasons. Some of the factors responsible for this undesirable development include environmental factors such as bush burning and biotic decimating factors that include human factors such as inordinate harvest pressure, over cropping and mode