An insect invasion of Antarctica: the past, present and future distribution of Eretmoptera murphyi (Diptera, Chironomidae) on Signy Island

Abstract

Rising human activity in Antarctica, combined with continued warming of the polar climate, means the risk of non‐native terrestrial species colonising and establishing in its biodiversity‐ and nutrient‐poor ecosystems is increasing. Of the five non‐native invertebrate species currently in terrestrial Antarctica, the flightless midge Eretmoptera murphyi (Schaeffer, The Museum of the Brooklyn Institute of Arts and Sciences 2:90–94, 1914) is perhaps the most persistent insect invader. Accidentally introduced to Signy Island (60°S) in the 1960s from sub‐Antarctic South Georgia (54°S), E. murphyi has steadily increased its distribution, however, its status has not been reassessed for a decade. Here, we update the distribution of E. murphyi on Signy, specifically assessing whether footpaths to regularly visited research sites represent dispersal corridors. Our findings show that both the abundance and range of E. murphyi have increased significantly since 2009, particularly along paths leading away from the original introduction site, and that the species is now on the cusp of moving into new valley systems. We identify a moderate association with soil/substrate and vegetation types and build Maximum Entropy (MaxEnt) models to predict areas of the island that may be at highest risk of future colonisation. As a detritivore with no competitors or predators, E. murphyi may have a major impact. For example, accelerating nutrient cycling which may have wider impacts on all levels of biodiversity. This study highlights the need for an assessment of current biosecurity protocols applied within the Antarctic Treaty system, as well as the need for systematic regular monitoring of introduced and invasive species in Antarctica.

Invasive non‐native species likely to threaten biodiversity and ecosystems in the Antarctic Peninsula region

“…While marine species dominate the list, key terrestrial and freshwater invertebrates were identified that could pose a threat by altering ecosystem function within this unique environment. Indeed, invertebrates have already been introduced and established on the South Orkney Islands (Signy Island) from South Georgia (Bartlett, Convey, Pertierra, & Hayward, 2019;Hughes & Worland, 2010).…”

Surviving the Antarctic Winter—Life Stage Cold Tolerance and Ice Entrapment Survival in The Invasive Chironomid Midge Eretmoptera murphyi

“…Data in the current study were collected from three sites within 3 m of one another. As E. murphyi has a distribution of at least 80,000 m 2 over an undulating landscape [55], the environmental conditions described here may not be representative of the entire distribution range due to likely variation in snow depth, as exemplified by the difference in minimum temperatures between this study and that of Davey et al [8], despite the same locale. It is worth noting, however, that the location of the temperature loggers in this study is associated with high E. murphyi abundance [55]; thus, prior conditions are not prohibitive to survival.…”

Antarctic: Climate Change, Fisheries, and Governance

“…The risks of establishment of invasive, nonindigenous species, under current climate change scenarios will continue to grow (e.g., in the Antarctic Peninsula Region, Ross Sea, and East Antarctic coastal areas) (Chown et al 2012a). As alien plants, invertebrates, and other taxa successfully colonize the Antarctic and sub-Antarctic, they can spread and potentially have major impacts on native ecosystems and species (Bartlett et al 2020;Hughes and Convey 2010;Hughes et al 2013Hughes et al , 2015. Individual tourist visitors to Antarctica carry more seeds on average than do governmental (science and support) personnel but, as vectors, the latter in total carry greater amounts of seeds of alien species than do tourists (Chown et al 2012a), while virtually all known introductions within Antarctica and the sub-Antarctic in recent decades (i.e., after the era of marine exploitation) are far more plausibly associated with national operator activities than those of the tourism industry (Frenot et al 2005).…”

“…For example, the presence of balanomorph barnacles and live individuals of the cosmopolitan pelagic barnacle, Conchoderma auritum, demonstrated the potential for non-native species to be transported to Antarctica this way (Hughes and Ashton 2017). Increasingly, modeling approaches are being used to predict potentially wide ranging future changes in distribution of both native and non-native terrestrial species in Antarctica (Bartlett et al 2020;Contador et al 2020;Hughes et al 2019;Pertierra et al 2017Pertierra et al , 2020.…”