Development of the Salt-Marsh Caterpillar Parasite, Exorista mella at Controlled Constant and Variable Temperatures in the Laboratory12

Abstract

The rate of development of Exorista mella (Walker) was determined in larvae of the salt-marsh caterpillar, Estigmenc acrea (Drury), reared on a semisynthetic diet. The egg stage required 100 hr at 68°F to 52 hr at 86°F. The egg and larval stages together required 28.1 days at 59 to 7.9 days at 86. The pupal stage was approximately of the same duration as that of the egg and larval periods and required 27.4 days at 59°F to 7.8 days at 86°F. Thirty-nine percent of the parasite larvae emerged from host larvae, 20% from pupae, and 15% remained within the host larvae. Fifty-nine percent of the parasitized host larvae had 1 larva, 23% had 2.10% had 3.6% had 4, and 2% had 5-7.