PROPORTIONS OF EGGS LAID BY AEDES-AEGYPTI ON DIFFERENT SUBSTRATES WITHIN AN OVITRAP IN TRINIDAD, WEST-INDIES

Ovitraps were exposed outdoors during wet and dry seasons in Trinidad to determine the proportions of eggs laid on three substrates: the wid ely-used hardboard 'paddle' (P), the water surface (W) and the inside surface of the ovitrap wall (S) in three types of blackened ovitrap: r ound, glass (RG), round, plastic (RP) and rectangular, plastic (SP). O f the 3556 eggs obtained, most (86.4%) were laid during the wet season when statistically significant differences were detected between subs trates but not between ovitrap types. Most eggs (>80%) were laid on P, significantly fewer (P < 0.005) on W, on S and on W + S, thus confirm ing the superiority of the paddle as a device for monitoring ovipositi on activity. Implications of these findings for the interpretation of Aedes studies using ovitraps are discussed.