Molecular identification and distribution of leatherjackets (Diptera: Tipulidae) in U.K. agricultural grassland

DNA barcoding is useful for the identification of morphologically cryptic invertebrates. An important application is for pest species, for which it is critical to determine the distribution, biology and ecology of damaging life stages in order to target management effectively. Tipula paludosa (Meigen) and Tipula oleracea (Linnaeus) leatherjackets, the larvae of crane flies (Diptera: Tipulidae), are pests of agricultural grassland in Europe and the U.S.A. and are difficult to distinguish morphologically. We used cytochrome c oxidase subunit I (COI) barcoding to identify leatherjackets from 19 permanent grassland fields over 2 sampling seasons on the Rothamsted Research North Wyke Farm Platform, south west UK, to assess species-level distribution and genetic diversity. Most larvae (94%) were found to be T. paludosa, comprising 18 haplotypes that were spread across the sampling site in a panmictic population. However, T. oleracea were found in low abundance (3% of larval samples) and only in the second year of sampling. Other morphologically similar Dipteran larvae (3%) were also found. This dominance of one species suggests that there may be underlying differences in species biology, such as choice of oviposition site and dispersal ability, which is in agreement with other studies and has implications for monitoring and management.