BIOECOLOGY OF Heteropoda venatoria (Linnaeus) (Araneae: Sparassidae) AND ITS IMPLICATIONS IN A TROPICAL BANANA AGROECOSYSTEM
JUDE A. EWUNKEM *
Department of Energy and Environmental Systems, North Carolina A and T State University, Greensboro, North Carolina, 27411, USA.
NELSON N. NTONIFOR
Department of Agronomic and Applied Molecular Sciences, University of Buea, P.O.Box 63, Buea, Cameroon.
MBUA CHRISTOPHE PARR
Department of Plant and Animal Sciences, University of Buea, P.O.Box 63, Buea, Cameroon.
*Author to whom correspondence should be addressed.
Abstract
To understand the possible reason(s) for the high population densities of the vagrant Heteropoda venatoria spiders in most commercial banana agro-ecosystems in Cameroon and marketed bananas, studies on their reproduction, development and habitat exploitation were undertaken. Courtship, mating and oviposition occurred at night. During copulation, the male embolus of one pedipalp is put into its mouth and then inserted into the female epigynum alternately for about 2.5 hours. Between 28-30 days later, a female produced a cream-whitish spherical cocoon of ca 20 mm in diameter and laid eggs therein. Thereafter, she picked and carried the cocoon underneath her abdomen with the aid of her pedipalps throughout an incubation period of about 30 days without feeding and hence significantly lost weight over time. Ensued spiderlings from the egg cocoon 31.9±0.7 days later, aggregated on the surface of the empty cocoon, but retreated into it when disturbed. The spiderlings moulted averagely once monthly. Total developmental period was significantly longer for females than males. Appendages lost during fouled moulting were regenerated in juveniles but not in adults. The female spiders are larger than males whose legs are longer and the terminal segments of their pedipalps enlarged. Field and laboratory sex ratios showed fewer males than females. The spider microhabitats in banana the agroecosystem included spaces in flower bracts, banana bunches, leaf petioles, and under banana pseudostem barks. The banana agroecosystem therefore provide “time-specific microhabitat and prey diversity” favourable for the spider subsistence for suppressing the populations of phytophagous insects on the crop. Therefore, the spider populations in banana farms merit judicious management to maximally exploit their benefits as natural enemies of insect pests on the banana crop.
Keywords: Courtship, oviposition, spider development, sexual dimorphism, sex ratio, microhabitats