Worms play a crucial role in soil health, acting as engineers of the underground ecosystem. Yet they face growing threats from drought and desertification across the country. An additional pressure comes from the arrival of Argentinian fireflies, which feed on these very organisms, potentially altering the delicate balance that sustains healthy soils and productive agriculture.
A research team from the Department of Biodiversity, Ecology and Evolution at the Complutense University of Madrid highlights an alien firefly with profound implications for European ecosystems. The species, Photinus signaticollis, originates from South America and has recently established populations in Spain, with notable presence in Girona.
This firefly species has expanded its range across the northeast Iberian Peninsula since 2016, crossing into the Pyrenees by 2019 and reaching southern France. Its larvae prey on worms, and at high population densities this feeding behavior could disrupt crucial soil communities and the processes they support in agriculture and land management.
Researchers remain concerned and are still assessing how far the invasion has progressed. They are examining patterns of colonization, ecological niches, and the potential geographic spread within Europe.
Using species distribution models, scientists have identified regions across Europe where the firefly could find suitable conditions if established. They note that accurate predictions rely on data from South America and the ecological status of climates similar to those around the Río de la Plata and Girona, where the species has shown affinity for habitat features resembling its native environment. The implication is that as long as climatic parallels exist, the firefly could continue to occupy new areas in Europe.
Photinus signaticollis, native to the temperate zones of Argentina and Uruguay, exhibits climatic traits that mirror parts of the western Mediterranean. This resemblance appears to have facilitated its successful colonization of the western Mediterranean region, where environmental conditions once shaped by the same temperature and humidity patterns support local life, including worm populations that drive soil fertility.
There do not appear to be any predators for these fireflies.
Initial findings indicate that seasonal temperatures align closely between the firefly’s native range and areas it has invaded in Europe. The combination of climatic suitability and a perceived lack of native predators or parasitoids may be a key factor behind the rapid buildup of individuals observed in recent years, from 2016 through 2023, and underscores the urgency of monitoring programs and risk assessments in the region.
Experts warn that the phenomenon has sometimes been labelled a neglected invasive issue. Limited resources and a narrow focus on biological invasions can hinder effective responses, allowing problems and threats posed by exotic species to accumulate and complicate management efforts for soil ecosystems and agricultural practices.
Reference work: Springer link 10.1007/s10841-023-00522-7
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Note: no contact address is provided in this rewritten piece. The content reflects ongoing scientific discussion about the spread and ecological impact of Photinus signaticollis in Europe.
Nature 2023, article on the distribution and ecological impact of Photinus signaticollis in Europe.