DEVELOPMENT OF 3 POPULATIONS OF COLEOMEGILLA-MACULATA (COLEOPTERA, COCCINELLIDAE) FEEDING ON EGGS OF COLORADO POTATO BEETLE (COLEOPTERA, CHRYSOMELIDAE)

Laboratory experiments were conducted to compare the preimaginal survi val, development rate, adult weight, and sex ratio of 3 Coleomegilla m aculata DeGeer populations feeding on Leptonotarsa decemlineata (Say) eggs and pea aphids, Acyrthosiphon pisum (Harris). Preimaginal surviva l of C. maculata from Iowa, Rhode Island, and Honduras reared on L. de cemlineata eggs alone ranged from 1.7 to 30%. The highest mortality of C. maculata immature stages occurred during the early (Ist and 2nd) s tadia. Higher preimaginal survival for Rhode Island population (30%) t han for Iowa (5%) and Honduras (1.7%) populations suggests that C. mac ulata in Rhode Island may be better adapted to feeding on L. decemline ata eggs as early instars. Development of C. maculata at 26 degrees C was slowest (18 d) on L. decemlineata eggs alone and fastest (13 days) on pea aphids alone. However, when Ist and 2nd instars of C. maculata were provided with aphids, followed by L. decemlineata eggs. there wa s no observed delay in larval development. Older C. maculata larvae re adily feed on L. decemlineata eggs, and in the presence of additional prey such as aphids for early instars, L. decemlineata eggs alone are an adequate diet for subsequent C. maculata development and survival.