| Abstrakt: |
Longevity, age-specific fecundity, and effect of light intensity on host-finding behavior of Apechthis Ontario (Cresson) and Itoplectis quadricingulatus (Provancher) (Hymenoptera: Ichneumonidae) were compared. Parasite interaction was assessed in elongate population cages, lighted on one end, dark on the other, and stocked daily along the light intensity gradient with host allotments. Numbers of hosts killed and parasite progeny produced were criteria used to compare single-species and mixedspecies performance. By these 2 criteria, I. quadricingulatus appeared to be the better single-species of parasite, but mixed-species performance was at least as good as either species alone, even taking into account the reduced efficiency of each species in mixed culture. The more rapid maturation of I. quadricingulatus allowed it to predominate at the beginning of the experiment, whereas A. Ontario predominated toward the end because of its greater longevity. I. quadricingulatus was influenced more by light intensity than was A. Ontario. |
