Preliminary studies on the life history and behaviour of the legume podborer, Maruca testulalis (Geyer), at Mbita Point on the shores of Lake Victoria have shown that most of the eggs (86%) of M. testulalis are laid on the leaf. Over 90% of such eggs laid on the leaf are oviposited on the lower leaf surface. Most adults were found to emerge between 2000 and 2300 hr. The number of eggs laid per female varied between 6 and 194, and over 72% of these were fertile. No larval or pupal diapause was observed.
Larval duration was 8–14 days and the pre-pupal stage lasted only 12–24 hr. The whole life cycle at Mbita Point was found to be about 20–57 days.
An important factor that previously discouraged detailed studies on the biology of M. testulalis is the fact that the eggs are translucent and extremely difficult to see against the background of the oviposition site. The discovery of these eggs was a major step in beginning to work on this important pest.