Thrips of the British Isles

Host plants

Plant names used here are based largely on Mabberley (2008), with the major exception of the plant Family names. In the British Isles, only 21 of the 177 recorded species are mycophagous, feeding on the fungi that grow on dead plant tissue, all in the Family Phlaeothripidae. Nearly all of the rest are phytophagous, with a very few species predaceous on other small arthropods. Most of these phytophagous species breed in flowers and pupate at soil level, but a few species breed only on leaves. The biology of many species remains unstudied, and apparent host-plant associations in much of the published literature on thrips are often based only on the presence of one or more adults. In contrast, the host records in the 1976 Royal Entomology Society's Handbook (Mound et al., 1976; also summarised by Pitkin, 1976) were based on the presence of larvae, and represent decades of field observations by Guy Morison. Despite the weakness of the available information it is clear that some species are polyphagous, whereas others exhibit varying levels of host specificity, and a few are monophagous – at least in Britain.

Some species of leaf-feeding thrips show strong preferences for either very young leaves (e.g., Scirtothrips species) or hard leaves (e.g., Heliothrips haemorrhoidalis). Most phytophagous species have their life-cycles aligned with those of their host plants. Species in the Thripidae associated with trees, such as Oxythrips ajugae or Thrips minutissimus, are usually found at peak numbers in the Spring, when the leaves are young or the flowers in bloom. By contrast, flower-living thrips of the chalk downlands are at their peak in mid-Summer. The common and widespread species whose adults are found throughout the Summer tend to be the most polyphagous. Thrips are taken generally only from plants within easy reach of the collector, and there is scant available information concerning those thrips that live in tree canopies. However, a species otherwise collected infrequently in Britain, Drepanothrips reuteri, was taken in large numbers by insecticide fogging of an oak canopy in Richmond Park (Palmer, 1986), whilst fogging of just three individual oak trees in the Wyre Forest, Worcestershire, yielded nine species of thrips, including five phlaeothripid fungus-feeding species (Skirrow, 2017). Similar studies in other parts of the world suggest that fungus-feeding Phlaeothripidae are abundant on dead branches in the canopy of trees.