Celatoria Diabroticae Shimer and Celatoria Setosa Coquillett: Tachinid Parasitoids of the Diabroticite Coleoptera

128 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.Diabroticite Coleoptera (Chrysomelidae;Galerucini) are destructive agricultural pests that are becoming increasingly difficult to control by chemical means.Biological control is an important aspect of any modern pest management program. Celatoria diabroticae Shimer and Celatoria setosa Coquillett are two parasitoids of the diabroticites, genus Acalymma and genus Diabrotica, that have been widely recorded in the U.S. for over 100 years. However, very little is known of their biology.Preliminary work indicated that literature host records were in error. Careful examination of literature records confirmed this likelihood. The first species described (C. diabroticae) was described in Illinois from Acalymma vittata Fabr. in 1871. A second species was described in California from Diabrotica undecimpunctata undecimpunctata Mannerheim. Coquillett described it and named it C. crawii (1890) but later declared it synonymous with C. diabroticae. It probably was not synonymous but Shimer's specimens are lost and his description is poor. A third species (C. setosa Coquillett) was found to parasitize A. vittata in 1914 (Walton 1914). This species probably is synonymous with C. diabroticae. Experiments to determine true host associations were designed. Larvae of C. setosa and C. diabroticae were implanted in ten species of Diabrotica and Acalymma beetles. Female flies were tested in an arena for host acceptance with these same species. C. setosa will accept and larvae survive and develop in A. vittata, A. trivittata, A. blandula. C. diabroticae can develop successfully in all species tested but females only accept D. undecimpunctata and and D. longicornis Say. These results agree with earlier data (Fischer 1981) concerning parasitization of field collected beetles.Laboratory rearing methods were developed. Previously these flies had been impossible to rear in captivity due to lack of mating and parasitizing in the laboratory.Following this, development rates were studied at three constant temperatures. The most successful constant temperature was 25(DEGREES)C. Centigrade degree days required for development to each stage are reported. Developmental threshold is approximately 14.0(DEGREES)C.Finally, a kairomone substance extractable from the cuticle of preferred adult beetle hosts was investigated by chemical analysis including gas and liquid chromatography and mass spectrometry. C. setosa was examined by scanning electron microscopy to locate sensory structures responsible for kairomone recognition. The kairomone appears to be a derivative of a long chain hydrocarbon that stimulates structures located on the female foretarsus and on a unique structure projecting from the ventral abdomen that contacts the host before parasitization.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD