The distribution and abundance of the British fungal‐breeding Drosophila

Abstract

Abstract. The distribution and abundance of five Drosophila species breeding in fungi are examined by attracting adult flies to baited traps and collecting fungal fruit bodies containing the larval stages. Changes in species frequency follow a temporal (seasonal and yearly), rather than a spatial (between and within woods) pattern. There is a regular diurnal pattern of activity in D.subobscura but not in D.phalerata. Temperature, light intensity, humidity and wind speed have no effect upon the daily activity of D.phalerata. Only temperature affects the activity of D.subobscura. Out of 125 species of fungi collected, only forty‐eight species produced Drosophila. However, the flies are even more selective, since only five species of fungi (Phallus impudicus, Polyporus squamosus, Amanita rubescens, Pluteus cervinus and Lactarius quietus) produce 80% of all Drosophila reared. The commonest species, D.phalerata, has two or three generations per year with a winter diapause. An outline of the yearly life cycle is given, with the major breeding sites for each generation indicated. Measures of niche overlap calculated from the data on individual fruit bodies are very low, suggesting that the five species are effectively isolated during the larval period. This ecological isolation is achieved by a summation of several niche dimensions, woodlands, seasons, fungal species, and individual fruiting body differences.