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Nest associates of Vespula atropilosa and V. pensylvanica in southeastern Washington State.

1975; Kansas (Central States) Entomological Society; Volume: 48; Issue: 1 Linguagem: Inglês

1937-2353

John F. MacDonald, R D Akre, W. B. Hill,

Diptera species taxonomy and behavior

From 1971-1973, 61 Vespula pensylvanica (Saussure) and 39 atropilosa (Sladen) nests were excavated and examined for the occurrence and possible adverse effects of nest associates. Five species of nest associates were commonly encountered in nest cavities or nests. Three associates were common to colonies of both yellowjacket species, but did not appear to influence colony development or decline: Dendrophaonia querceti (Bouche) (Diptera: Muscidae); Fannia spp. (Diptera: Muscidae); and Cryptophagus pilosus (Gyllenhof) (Coleoptera: Cryptophagidae). Sphecophaga vesparum burra (Cresson) (Hymenoptera: Ichneumonidae), a pupal parasitoid in over 80% of atropilosa nests, appeared to adversely affect development of incipient colonies. Triphleba lugubris (Meigen) (Diptera: Phoridae), common in pensylvanica nests in late September and October, appeared to influence colony decline by destroying developing queen pupae thereby lowering colony productivity. Subterranean nests, and nest cavities of yellowjackets, with a refuse pile below, provide a suitable habitat for many arthropods. Most are scavengers in debris below the nest or on fungi growing on the nest carton. Previous workers (Tuck, 1896; Biegel, 1953; Kemper and Dohring, 1967; and Spradbery, 1973) listed nest associates of vespines; Biegel and Spradbery discussed their importance to colony decline. Our objective was to determine associates common in colonies of Vespula pensylvanica (Saussure) and atropilosa (Sladen) which might adversely influence development of incipient colonies or contribute to decline of mature colonies. Materials and Methods All yellowjacket colonies studied were numbered chronologically as located beginning with the letter V. This served as an identification number for colonies, nests after analysis, and nest associates. During 1971-1973, 61 pensylvanica and 39 atropilosa nests were excavated and examined. Colonies were sacrificed at periodic intervals 1 Scientific paper number 4277, Washington State University College of Agriculture Research Center. Work done under project 0037 and financed in part by National Science Foundation Grant GB-30922 and United States Department of Agriculture Cooperative Agreement. 2 Research Assistant, Professor, and Scientific Aide, respectively, Department of Entomology, Washington State University, Pullman, Washington. Received for publication January 7, 1974. This content downloaded from 157.55.39.92 on Wed, 22 Jun 2016 06:48:42 UTC All use subject to http://about.jstor.org/terms 54 Journal of the Kansas Entomological Society during the seasons to determine occurrence and possible adverse effects of nest associates. Colonies were killed the night prior to excavation by pouring carbon disulfide (ca. 75-100 ml) down the entrance tunnel and immediately plugging the hole with cotton soaked in CS2. Nests, and loose soil and debris below nests were placed in separate plastic bags for transport to the laboratory. Nests were separated into individual combs, nest envelopes torn apart, and soil and debris spread out in white pans to search for associates. Nest material was not berlesed since CS2 used to kill adult yellowjackets also killed the associates. Results and Discussion Cryptophagus pilosus Adults of C. pilosus were found in 7 of 39 atropilosa and 10/61 pensylvanica nests. They were present in low numbers (1-8) in atropilosa nests from mid-September to November. Larvae of C. pilosus were not found in nests remaining in the field, but nests of 3 atropilosa colonies transplanted into screenhouses produced large numbers through out the nest envelope, combs, and cells. Adults of C. pilosus were found in low numbers (1-18) in pensylvanica nests, but only in nests excavated after the first of October; 4/6 nests in 1972, and 6/22 in 1973. Larvae of C. pilosus were not found in pensylvanica nests. Infestations of C. pilosus in nests of both yellowjacket species occurred late in the seasonal cycle, usually after nest decomposition had begun. Larvae were probably commensals, feeding on fungi in nests as described by Spradbery (1973) for Cryptophagus spp. in nests of British vespines.