Thrips of the British Isles

Future distributions and climate change

In connection with climate change, insect species have been recorded moving northwards in Europe, including both into and within Britain, (e.g., Parmesan et al., 1999; Hickling et al., 2005; Sparks et al., 2007). It may be inferred that this is likely to apply also to Thysanoptera, but given both the lack of robust baseline distribution data for the purposes of comparison and the dynamic relationship between thrips and winds it is difficult to draw definitive conclusions. Thus, recent first findings in Britain of continental European species such as Frankliniella pallida, Odontothrips confusus and Thrips linariae may be indicative of a continental scale northward range expansion. Similarly, there is a general impression that within Great Britain the ranges of many species, such as Dendrothrips degeeri, Stenchaetothrips biformis and Haplothrips hukkineni, have been expanding northwards in recent decades. However, historic collecting gaps, particularly in the Midlands and parts of the north of England, make it difficult to assert, with certainty, a causal link to changes in climate. Furthermore, other factors may be at play including habitat loss due to post war agricultural intensification and urban sprawl (e.g., Fuller, 1987; Ridding et al., 2015), and the effect that eutrophication has had on the distribution of the host plants of specified mono- or oligophagous insects including thrips. These effects increase the chances of stochastic effects such as weather events wiping out individual populations with consequences, in turn, for distribution patterns at least at a regional scale (Platts et al., 2019). Such weather events, may themselves increasingly be the result of a changing climate. However, there is one confirmed example of a thrips species moving northwards, Thrips major moving through Scotland into Aberdeenshire over the past sixty years (Collins, 2022), as its prior absence there is confirmed by the extensive fieldwork of Guy Morison in North East Scotland in the mid twentieth century. Furthermore, climate change will almost certainly aid accidental introductions to spread and breed outdoors, as seems to be currently true of Neoheegeria dalmatica. Some thrips species are known only from Scotland, in some cases only from North East Scotland, but a lack of data leaves their on-going response to a changing climate unknown. Likewise, any changing distribution patterns within the island of Ireland will have been happening completely unrecorded. It should be noted that populations of some thrips species are possibly more stable; for example, Dendrothrips saltator has been recorded only twice in Britain, but these findings were 79 years and only a few miles apart.