Diversity of the scuttle fly (Diptera : Phoridae) communities in the plantations of moist pine forests of the Bialowieza Primeval Forest and the Tuchola Forest (Poland)

Scuttle fly communities of pine plantations were investigated in 1986 and 1987 in two sites, Bialowieza Primeval Forest and Tuchola Forest. Flies were collected using yellow plastic bowls placed on the ground. Up to now 108 species were identified, and 46 occurred on both sites. Although the number of species was very similar in Tuchola Forest (77) and Bialowieza Primeval Forest (75) species diversity was considerably lower on the former site (p < 0.05). Ten dominant species were common: Megaselia brevicostalis, M. giraudii, M. manicata, M. nigriceps, M. pleuralis, M. pulicaria- complex, M. pumila, M. verralli, Metopina oligoneura and Triphleba opaca. Five of these were characteristic of both communities (Megaselia verrali, M. brevicostalis, M. pumila, Metopina oligoneura and Triphleba opaca). Similarity of qualitative composition for dominants was rather high (S empty set = 0.67), but the quantitative similarity was low (Mo = 0.26). During two study seasons in the community of the Bialowieza Primeval Forest the dominance structure did not change markedly and Megaselia verralli was the dominant (over 20%). M. verralli was also the dominant (ca. 30%) in the communities in the Tuchola Forest in 1986, but next year M. pulicaria- complex (ca. 50%) dominated. Most of the dominant species are multivoltines and generalists. In Tuchola Forest the disturbances caused by the chemical treatment against Neodiprion sertifer might be the main factor in the phorid community in 1987 (extremely high dominance of Megaselia pulicaria-complex).