The distribution and biology of Lonchopteridae (Diptera) in upland regions of northern England

Abstract

Abstract. 1. A survey was made of the distribution of Lonchopteridae over 2 years at forty sites in northern England. Material was collected by pitfall trapping.2. Two species, Lonchoptera lutea and L.furcata, were taken in approximately similar numbers. No other species were recorded.3. Considerable separation of the two species was found, with both species occurring at ten sites, whilst one species only was taken at twenty‐five sites. L.furcata occurred coinrnonly on upland mineral sods, shallow peat soils and on lowland bogs whilst L.lutea was numerically most abundant on upland blanket bog.4. Almost 39% of the L.lutea specimens and 14% of the L.furcata captures were males.5. The capture of numbers of males of L.furcata is unusual, since the species is regarded as being parthenogenetic and males occur only in a very small part of the species' range. Confirmation of the association between the males and females of L.furcata is given, whilst there is close agreement between the cliaetotaxy of British males and females, and British and continental European females. The suggestion that the males belong to an undescribed species is rejected.6. The seasonal capture of L.lutea adults is similar at all altitudes. Captures of males of L.furcata show an abrupt seasonal change above and below about 420 m; captures being in mid‐summer in the higher altitude zone and between October and December at lower altitudes. The captures of females of L.furcata show the same trend, but this is partially obscured by the longer life‐span of the females. It is suggested that this difference represents a change in the lifecycle, possibly from an annual to a biannual one at the higher altitudes.7. The biology and distribution of the Lonchopteridae at low altitudes requires investigation.