Some aspects of the biology of Conchyloctenia nigrosparsa Boh. (Coleoptera: Chrysomelidae), a sweet potato defoliator in southern Nigeria.


ABSTRACT: The behaviour and the biology of Conchyloctenia nigrosparsa Boh. were investigated in sweet potato, Ipomoea batatas (L.) Lam; plots and in the laboratory. Adults and larvae fed voraciously on sweet potato leaves. Females required frequent copulation to sustain oviposition. Mating reduced adult life by 18-20
days, mated females outlived mated males by 6.0 days. A mated female laid 24.0 oothecae, each containing about 30.0 eggs. The stadium for 1st, 2nd, 3rd, 4th and 5th, instars was 2;1.;l;3 and 4 days respectively. The developmental time from egg to adult emergence was 26-27 days when C. nigrosporsa was reared on L batatas, I repens (L.), Lcairica (L.) and L involucrata (Beauvois). The data also showed that the larval instars could be separated accurately by measuring the head capsules. Fifteen to six percent of eggs of C. nigrosparsa were parasitised by Tetrastichus sp. Hotea gambiae,
Westw., Afrius purpureus Westw. and Rhincoris bicolor (p.) preyed actively on the. immature stages of
C. nigrosparsa.

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