Distribution of adult Australian wingless scorpionflies (Mecoptera: Apteropanorpidae)

Abstract

Apart from a few species of interest to behavioural ecologists, the biology and ecology of most scorpionfly species is not well known. The Apteropanorpidae is a family of wingless Mecoptera endemic to Tasmania, comprising four described species in the genus Apteropanorpa. Intensive field surveys for Apteropanorpa species were conducted from 2001 to 2003 in a range of altitudes and habitats in several parts of Tasmania, and these yielded a large number of adult specimens. Adults were collected from a total of 26 plant species and subspecies belonging to nine families, including both angiosperms and gymnosperms. There was a positive relationship between the total number of plant species sampled at each site and adult abundance, so that sampling a greater number of plant species increased the number of adults collected. There was a positive relationship between plant size and abundance at five out of eight sites, such that adults were more likely to aggregate on larger plants. The overall sex ratio of adults on plants was 1:1. An extremely large series of adults was collected in pitfall traps established along an altitudinal transect on Mt Weld, southern Tasmania, from January to April 2001. Pitfall‐trapped adults comprised two species: Apteropanorpa warra at altitudes ≤1000 m and the alpine species A. tasmanica at altitudes of 1100–1300 m. Total abundance of A. warra in pitfall traps on Mt Weld was low; however, the number of pitfall‐trapped female A. tasmanica was very large and markedly increased linearly with altitude from 1100–1300 m in both March and April 2001. The number of male A. tasmanica was also large and increased markedly from 1100 to 1200 m in both March and April. Data strongly indicate an autumnal peak in adult abundance for the Apteropanorpidae, as is the case for other Australian Mecoptera.