SEASONAL BEHAVIOR OF LARVAE OF CTENICERA SPP. AND OTHER WIREWORMS (COLEOPTERA:ELATERIDAE), IN RELATION TO TEMPERATURE, MOISTURE, FOOD, AND GRAVITY

Abstract

In a gradient, nearly mature larvae of Ctenicera destructor (Brown) aggregated at higher average temperatures than did those of C. aeripennis (Kby.), Hypolithus bicolor Esch., or Limonius pectoralis Lec. Larvae of C. destructor from a field in wheat were distributed at higher temperatures than were those from fallow, and larvae from fallow were distributed at higher temperatures with food than without, Larvae from most of the above populations showed significant seasonal variations in distribution in the temperature gradient.Larvae of C. destructor from fields in wheat and fallow avoided dry soil more at the higher than at the lower temperatures without food, and more at 50° and less at 86° than at 68° F with food. Those of H. bicolor preferred moister soils than did those of C. destructor when food was present.The feeding activities of larvae of the two Ctenicera spp. were similar. They attacked and destroyed about 10 times as many seeds as those of H. bicolor or L. pectoralis. The feeding activities of larvae of each of the four species varied significantly with seasons. Larvae of C. destructor from fields in wheat did not feed appreciably less than those from fallow during the frost-free seasons. The feeding activities of larvae from fallow were directly related to temperature in the range 50–86° F, and to moisture in the range 5–25% content by weight in loam soil.Larvae of C. destructor showed positive responses to gravity.