摘要:

Body weight, reproduction, and longevity of mated and unmated femalePodisus maculiventris(Say) were measured under low and high numbers of prey,Epilachna varivestisMulsant (Coleoptera: Coccinellidae). Under low rates of predation, the predator maintained longevity apparently at the expense of reproduction. Predators fed less frequently oviposited less often and later in life. Body weight of females was dependent on diet; females fed more frequently weighed more than those fed infrequently. Results are compared with previous life history studies of this predator. We found similarities in our results to other studies on longevity and reproduction ofP. maculiventrisprovided other types of prey. The trade-off between reproduction and longevity may be a response to environments with temporal variation in prey abundance.

ISSN:1754-5692    

DOI:10.1093/ee/22.5.1192

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

Two methods for initiating epizootics ofEntomophthora muscae(Cohn)Fresenius in house fly,Musca domesticaL., populations were evaluated on New York dairy farms. First, 500 fresh, laboratory-infected fly cadavers were placed weekly for 10wk inside barns in areas of high fly activity. Second, 2,500 living, infected flies were released on each of two occasions spaced 3 wk apart. Releases were started in mid-June. Three farms were used for each treatment plus three control farms. TheE. muscaeused for the releases had been isolated from house flies collected from dairies the year before and had been maintained by continuous fly-to-fly passage. Prevalence rates on both types ofE. muscaerelease farms were twice as high (23–28%) as on control farms (12%)in the weeks after the start of the releases. Releases were more effective on farms with high fly populations than on farms with low fly populations. Examination of conidia indicated that the released strain (8–18 nuclei per conidium) became established as a result of the releases. Epizootics occurred on all farms, including controls, in September through November. Infections in the spring were exclusively with a strain ofE. muscaewith 2–8 nuclei per conidium; by fall, most infections (86–93%) were with a strain with 8–18 nuclei per conidium, even on control farms. Nuclear densities in the laboratory culture remained constant at 8–18 nuclei per conidium during this shift in wild infections. Neither of theE. muscaetreatments significantly reduced fly populations.

ISSN:1754-5692    

DOI:10.1093/ee/22.5.1201

出版商:Oxford University Press    

年代:1993

数据来源: OUP

ISSN:1754-5692    

DOI:10.1093/ee/22.5.1209

出版商:Oxford University Press    

年代:1993

数据来源: OUP

ISSN:1754-5692    

DOI:10.1093/ee/22.5.1210

出版商:Oxford University Press    

年代:1993

数据来源: OUP