J. New York Entomol. Soc. 103(2):165-169, 1995 DOLICHOVESPULA (HYMENOPTERA: VESPIDAE), HOSTS OF APHOMIA SOCIELLA (L.) (LEPIDOPTERA: PYRALIDAE) Parker Gambino Bronx High School of Science, 75 West 205th Street, Bronx, New York 10468 — Abstract. CaterpillarsofthemothAphomiasociella (L.)werecollectedfromactivecolonies of Dolichovespula arenaria (F.) and D. maculata (L.), the first documented new world hosts forthis nest inquiline. Caterpillars held indoors were successfully rearedto adults. Emergences coincided with typical flight period ranges in nature, overlapping the early phases of vespine colony development. The bumble bee wax moth Aphomia sociella (L.) is an inquiline of bumble bee and vespine wasp colonies. It is widely distributed in Europe, where its life cycle, habits, and host range have been described (Sladen, 1912; Beirne, 1952; Kemper and Dohring, 1967; Pouvreau, 1967; Alford, 1975). Larvae developing within the host nest may consume nest materials, stored food, meconia and other wastes, and immature stages of the host insect. The silken webbing, tunnels, and cocoons spun by A. sociella caterpillars are dense and difficult to penetrate. Heavy infestations at vespine colonies can destroy large areas of comb (Fig. 1) In North America, publishedreports referonly tothe distributionofadults (Forbes, 1923), and specific host records are lacking. In the present study I document the occurrence ofA. sociella caterpillars in active colonies oftwo Dolichovespula Roh- wer species, and offer additional notes on its habits and distribution. MATERIALS AND METHODS Nests ofpotential vespine hosts ofA. sociella from two regions ofNorth America were examined. From 1984-1988, 131 nests were collected from Alameda, Contra Costa, and San Francisco Counties, California. From 1992-1994, 108 nests were collected from Dutchess, Putnam, and WestchesterCounties, New York, andFairfield County, Connecticut. Each nest was removed from its natural setting, its envelope stripped, and combs separated to search forA. sociella caterpillars or webbing. Five infested nests were held in clear plastic containers for up to two weeks to allow adult wasps to eclose. Caterpillars and the associated matrix of webbing and nest materials were then transferred to cardboard cans (i.e., not exposed to light) and held indoors at approximately 10°C to rear adults moths. The area around an incandescant night light at Brewster (Putnam County), New York was inspected for alighted adults during evenings from April to November in 1992-1994. Adult specimens in the collections ofThe American Museum ofNatural History and Cornell University were examined for additional distributional and pho- nological data. 166 JOURNAL OF THE NEW YORK ENTOMOLOGICAL SOCIETY Vol. 103(2) Fig. 1. Dolichovespula arenaria nest diss—ected by Aphornia sociella caterpi—llars. Nest en- velope has been removed to show interior: a mass ofA. sociella coccons; b upper combs engulfed in matrix of silk webbing; small dark spots scattered throughout are caterpillarfeces. RESULTS AND DISCUSSION No A. sociella were detected in California, a finding corroborated by previous surveys of Pyralidae in that state (J. Powell, pers. comm.). In the east, one adult female was collected at Brewster on 25 June 1993.A. sociella caterpillars werefound only in nests of Dolichovespula arenaria (F.) and D. maculata (L.) (Table 1), rep- Table 1. Colonies ofVespinae examined forA. sociella. Number Number examined infested California (1983-1987) Dolichovespula arenaria 65 0 Vespula pensylvanica 36 0 Vespula vulgaris 30 0 New York/Connecticut (1992-1994) Dolichovespula arenaria 44 6 Dolichovespula maculata 59 3 Vespula flavopilosa 3 0 Vespula maculifrons 2 0 1995 HOSTS OFAPHOMIA SOCIELLA 167 Fig. 2. Collection localities forAphomia sociella; open circles representinfestedDolichov- espula colonies; asterisk represents adult moth. resenting the first new world host records as well as new distribution records for New York State (Fig. 2). Data are inconclusive regarding Vespula Thomson spp. as hosts, due to the small sample size from New York and Connecticut. In Europe it is unusual for A. sociella to occur in subterranean Bombus nests (Beirne, 1952; Alford, 1975). This pattern, if extended to A. sociella's selection among potential vespine hosts, would lead to specialization on Dolichovespula, which typically build exposed aerial nests, rather than Vespula, whose nests are typically subterranean or concealed (Akre et al., 1980). Patterns of comb damage and silken webbing suggested that caterpillars were initially present in the topmost combs ofinfested nests. A. sociella is not an obligate s 168 JOURNAL OF THE NEW YORK ENTOMOLOGICAL SOCIETY Vol. 103(2) entomophage (Schousboe, 1980), and hosts may escape harm if contact with cater- pillars is avoided. Coexistence within the nest may be accomplished ifthe infestation is light or occurs late in the colony cycle, since vespine wasps expand the nest downward by adding combs to the bottom, essentially abandoning the upper combs for rearing purposes after the cells have been used several times (Akre et al., 1980). Even heavy caterpillar infestations may cause little harm if vigorous colony growth has produced a nest large enough to accomodate both species. None of the infested D. maculata colonies, including one supporting a heavy caterpillar load, suffered apparent damage from the presence of the inquiline. In contrast, most of the D. arenaria colonies containing A. sociella caterpillars were in a weakened condition, as evidenced by invasion of active combs, low worker populations, or overall de- terioration of the nest prior to the construction of large (reproductive) cells (Fig. 1). However, the role ofA. sociella in D. arenaria colony failure is not clear, as colonies ofthis species may be weakened early in the colony cycle by invasion by the social parasite D. arctica (Rohwer) or usurpation struggles with other vespine queens (Greene, 1991), thus predisposing them to both premature decline and invasion by A. sociella. Fragments ofall nests held indoors yielded adults. In 1992-1993 (one nest) emer- gence was in March and April; in 1993-1994 (four nests) emergence was from April to early July. Although the developmental rates for insects held indoors were likely to differ from those experiencing natural climate conditions, the emergence ofmoths from the experimental nests was consistent with flight period ranges observed in the northeastern United States, coinciding with the early phases ofBombus and vespine colony development. Since the defenses of host colonies become more vigorous as worker populations increase during the summer, A. sociella" early presence affords it an opportunity to enter and oviposit at nests while they are relatively poorly defended. ACKNOWLEDGMENTS J. Powell identified the moths and shared unpublished information on A. sociella\ distribu- tion. E. Quinter and R. Hoebeke assisted in making available the collections ofThe American Museum of Natural History and Cornell University, respectively. The East Bay Municipal Utility District, the East Bay Regional Park District, and the University ofCaliforniaprovided access to grounds where wasp nests were collected. LITERATURE CITED Akre, R. D., A. Greene, J. F. MacDonald, P. J. Landolt and H. G. Davis. 1980. Yellowjackets ofAmerica North ofMexico. U.S.D.A. Handbook #552. Alford, D. V. 1975. Bumblebees. Davis-Poynter, London. Beirne, B. P 1952. British Pyralid and Plume Moths. Frederick Warne & Co., London. Forbes, W. T. M. 1923. The Lepidoptera of New York and neighboring states. Cornell Univ. Agric. Exp. Sta. Mem. #68. Greene, A. 1991. Dolichovespula and Vespula. Pages 263-305 in: K. G. Ross and R. W. Matthews (eds.). The Social Biology ofWasps. Cornell Univ. Press, Ithaca. Kemper, H. and E. Dohring. 1967. Die sozialen Faltenwespen Mitteleuropas. Paul Parey, Ber- lin. Pouvreau, A. 1967. Contribution a I’etude morphologique et biologique d'Aphomia sociella 1995 HOSTS OFAPHOMIA SOCIELLA 169 L. (Lepidoptera, Heteroneura, Pyraloidea, Pyralididae), parasite des nids de bourdons (Hymenoptera, Apoidea, Bombus Latr.). Insects Sociaux 14(l):57-72. Schousboe, C. 1980. Fund afAphomia sociella (L.) (Lepidoptera: Pyralidae) i reder afgede- hams og mus. Entomol. Meddr. 47:117-118. Sladen, F. W. L. 1912. The Humble-Bee. Its Life History and How to Domesticate It. Mac- Millan & Co., London. Received 5 June 1995; accepted 4 October 1995.