Abstract.1The distribution and abundance of fiveDrosophilaspecies breeding in fungi are examined by attracting adult flies to baited traps and collecting fungal fruit bodies containing the larval stages.2Changes in species frequency follow a temporal (seasonal and yearly), rather than a spatial (between and within woods) pattern.3There is a regular diurnal pattern of activity inD.subobscurabut not inD.phalerata.Temperature, light intensity, humidity and wind speed have no effect upon the daily activity ofD.phalerata.Only temperature affects the activity ofD.subobscura.4Out of 125 species of fungi collected, only forty‐eight species producedDrosophila.However, the flies are even more selective, since only five species of fungi (Phallus impudicus, Polyporus squamosus, Amanita rubescens, Pluteus cervinusandLactarius quietus) produce 80% of allDrosophilareared.5The 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.6Measures 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 difference