Starmer, William T., and Alex Weir. 2001. Laboulbeniales associated with the Drosophila affinis subgroup in central New York. Dros. Inf. Serv. 84: 22-24.
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Laboulbeniales
associated with the Drosophila affinis
subgroup
in central New York.
Starmer, William T.,1 and Alex
Weir2. 1Biology Department, Syracuse
University, Syracuse, NY 13044, and 2Faculty of Environmental and
Forest Biology, SUNY College of Environmental Science and Forestry, 350 Illick
Hall, 1 Forestry Drive, Syracuse, NY 13210.
Introduction
The fungal parasites of
insects are not well known and those host-parasite lists that have been published
(e.g.,
Leatherdale, 1970) usually fail to incorporate the most diverse groups of
entomogenous fungi, including members of the ascomycete order Laboulbeniales. These fungi form fruiting structures on
the integument of a wide range of insects and other arthropods, and are considered
to be obligate ectoparasites. Most
of the described parasite species are associated with beetles (Coleoptera)
as hosts. The Laboulbeniales
parasites of flies (Diptera) have received less attention. Fungal parasites of Diptera include species
in the large genus Stigmatomyces, with more than 100 described species.
These are known on a range of families including Agromyzidae, Chloropidae,
Diopsidae, Dolichopodidae, Ephydridae, Muscidae, and Sphaeroceridae. The very first Stigmatomyces species to be described
from North America was recorded from New York on a species of Drosophila (Peck, 1885, as Appendicularia). In this report we document the incidence
of Laboulbeniales in a temporal study of temperate drosophilids in central
New York, USA.
Methods
Adult Drosophila and related species were
captured by netting and aspirating flies from compost and decaying mushrooms
in and around Green Lakes State Park, New York, during late September 1999
and during the Spring and Summer of 2000. Individuals were inspected under CO2 anesthesia
with a Wild M-5 binocular microscope at 25-50×.
Results
Only flies in the Drosophila
affinis
subgroup of the obscura group were found to have Laboulbeniales associated with them.
Table 1 details the incidence and proportion of the adults carrying
the fungi.
Approximately 10% of the
flies were infected. However, males captured outnumbered females 1058 to 154.
Considering the sexes separately, the proportion ± s.e. of infected
individuals (averaged over date collected and according to sex) was 0.008
± 0.006 for females and 0.105 ± 0.030 for males (pooled species). The percentage of males and females infected increased then
decreased with month during 2000 (Table 2).
Seventeen additional species in the family Drosophilidae
were inspected (Table 3) and none was infected.
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Table 2. Percentage
of infected Drosophila affinis subgroup
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Discussion
Earlier inspection (Starmer,
Polak, and Weir, unpublished) of Drosophila species in the Smoky Mountains
of North America revealed Stigmatomyces infecting affinis subgroup drosophilids
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These observations coupled with
this report and with earlier records showing D. obscura,
D. subobscura
are hosts in Europe (Dainat, et al., 1974) indicate that within the genus Drosophila there is potentially a
unique association of the fungus with obscura group Drosophila species. Other drosophilids known to have Laboulbeniales
(i.e., Stigmatomyces species) associated with them are Drosophila
funebris
(Thaxter, 1896; Blair, 1947; Picard, 1913), D. nigricornis (according to Wheeler
this name has uncertain validity) (Weir and Rossi, 1995), D. confusa (= Hirtodrosophila
confusa)
(Dainat, et al.,
1974) and species in Scaptomyza (Dainat and J.-F. Manier, 1974), Leucophenga, and Zaprionus (Tavares, 1985).
Acknowledgments: Thanks to Jon D. Livingston, Park Manager
of Green Lakes State Park, for permission to collect in the Park.
References: Basden, E.B., 1977, Dros. Inf. Serv. 52: 54; Blair, K.G., 1947, Entomologist's Monthly Magazine 83: 129; Dainat H., J.-F. Manier, and J. Balazuc 1974, Bulletin de la Societe Mycologique de France 90: 171-178; Dainat, H., and J.-F. Manier, 1974, Bulletin de la Societe Mycologique de France 90: 217-221; Leather
dale, D., 1970, Entomophaga 15: 419-435;
Picard, F., 1913, Bulletin de la Societe Mycologique de France 29:
503-571; Tavares, I.I., 1985,
Laboulbeniales (Fungi, Ascomycetes). Mycologia Mem. 9: 1-627; Thaxter, R., 1896, Mem. Amer. Acad. Arts. Sci., XIII: 187-429;
Thaxter, R., 1931, Mem. Amer. Acad. Arts. Sci., XVI: 1-435;
Weir, A., and W. Rossi, 1995, Mycol. Res. 99: 841-849.