TEMPERATURE EFFECTS ON SURVIVAL AND DEVELOPMENT OF HELEIDOMERMIS-MAGNAPAPULA IN THE LABORATORY

The mermithid Heleidomermis magnapapula Poinar and Mullens, a parasite of the biting midge Culicoides variipennis (Coquillett), was exposed to constant temperatures in the laboratory. Survival of the free-livin g stages and development times of eggs and the parasitic phase were in versely related to temperature. Average preparasite longevity was 70, 46, 42, and 22 hours at 15.6, 21.1, 26.7, and 32.2 C, respectively. Fe males survived significantly longer than males. Longevity in days (fem ales/males) at different temperatures was 17.3/11.0 at 4.4 C, 9.0/8.2 at 15.6 C, 5.9/5.1 at 21.1 C, 5.2/4.7 at 26.7 C, and 4.4/3.6 at 32.2 C . Embryogenesis required 44 +/- 2 degree days above a thermal minimum of 10.1 C, while parasitic development in host larvae required 214 +/- 10 degree days above a thermal minimum of 8.9 C. Parasite responses t o temperature were very closely related to temperature-dependent host development patterns.