Potential spread of the invasive North American termite, Reticulitermes flavipes, and the impact of climate warming

The destructive subterranean termite Reticulitermes flavipes (Blattodea: Rhinotermitidae) can colonize arid territories

Reticulitermes flavipes, one of the most destructive subterranean termite species, has been detected for the first time in an arid territory: Lanzarote (Canary Islands, Spain). This invasive species was introduced into several countries but never such a dry region. Although there are places with presence of this termite at similar or even higher temperatures, none has annual rainfall (10.1 mm) as low as Lanzarote. On this island it is present in semi-desert, near an affected urban area. Distribution, genetic, climate and host-plant data are evaluated to track and understand its invasion process in the archipelago.

Predicting the Habitat Suitability and Distribution of Two Species of Mound-Building Termites in Nigeria Using Bioclimatic and Vegetation Variables

Temperature is an important factor determining the abundance, distribution and diversity of termite species. Thus, termites are affected by changing climate and have to adopt different means of surviving in order to avoid extinction. Using termite occurrence data, bioclimatic variables and vegetation cover, we modelled and predicted the current and future habitat suitability for mound-building termites in Nigeria. Of the 19 bioclimatic variables and the vegetation index (NDVI) tested, only six were significant and eligible as predictors of habitat suitability for the mound-building termites Macrotermes subhyalinus and M. bellicosus. Under current climatic conditions (2022), the northwest, northeast and central regions are highly suitable for M. subhyalinus, while the distribution of M. bellicosus decreased in the North West, North East and in the Central region. However, regarding habitat suitability for the future (2050), there was a predicted range expansion into suitable areas for the two termite species. The increase in temperature due to global warming has an effect which can either result in migration or sometimes extinction of termite species within an ecosystem. Here, we have predicted habitat suitability for the two mound-building termite species under current and future climatic scenarios, and how the change in climatic variables would lead to an expansion in their range across Nigeria.

Globalization and the anthropogenic spread of invasive social insects

Social insects are among the worst invasive species and a better understanding of their anthropogenic spread is needed. I highlight recent research demonstrating that social insects have been dispersed since the early beginnings of globalized trade and in particular after the Industrial Revolution, following two waves of globalization. Many species have complex invasion histories, with multiple independent introduction events and frequent secondary spread. The major source and recipient regions differ markedly across ants, wasps, termites and bees, probably linked to their different introduction pathways. At a more local scale, anthropogenic factors such as irrigation, urbanization or the presence of railways facilitate invasions. In the future, social insect invasions could further accelerate due to intensifying global trade and novel introduction pathways.

Extensive human-mediated jump dispersal within and across the native and introduced ranges of the invasive termite Reticulitermes flavipes

As native ranges are often geographically structured, invasive species originating from a single source population only carry a fraction of the genetic diversity present in their native range. The invasion process is thus often associated with a drastic loss of genetic diversity resulting from a founder event. However, the fraction of diversity brought to the invasive range may vary under different invasion histories, increasing with the size of the propagule, the number of reintroduction events, and/or the total genetic diversity represented by the various source populations in a multiple-introduction scenario. In this study, we generated a SNP data set for the invasive termite Reticulitermes flavipes from 23 native populations in the eastern United States and six introduced populations throughout the world. Using population genetic analyses and approximate Bayesian computation random forest, we investigated its worldwide invasion history. We found a complex invasion pathway with multiple events out of the native range and bridgehead introductions from the introduced population in France. Our data suggest that extensive long-distance jump dispersal appears common in both the native and introduced ranges of this species, probably through human transportation. Overall, our results show that similar to multiple introduction events into the invasive range, admixture in the native range prior to invasion can potentially favour invasion success by increasing the genetic diversity that is later transferred to the introduced range.

Area-Wide Elimination of Subterranean Termite Colonies Using a Novaluron Bait

We investigated the use of termite baiting, a proven system of targeted colony elimination, in an overall area-wide control strategy against subterranean termites. At two field sites, we used microsatellite markers to estimate the total number of Reticulitermes colonies, their spatial partitioning, and breeding structure. Termite pressure was recorded for two years before and after the introduction of Trelona® (active ingredient novaluron) to a large area of one of the sites. Roughly 70% of the colonies in the treatment site that were present at the time of baiting were not found in the site within two months after the introduction of novaluron. Feeding activity of the remaining colonies subsequently ceased over time and new invading colonies were unable to establish within this site. Our study provides novel field data on the efficacy of novaluron in colony elimination of Reticulitermes flavipes, as well as evidence that an area-wide baiting program is feasible to maintain a termite-free area within its native range.

Invasion Dynamics of A Termite, Reticulitermes flavipes, at Different Spatial Scales in France

Termites are social insects that can also be major pests. A well-known problem species is the subterranean termite, Reticulitermes flavipes. It is invasive in France and is thought to have arrived from Louisiana during the 18th century. While the putative source of French populations has been identified, little is known about how the termite spread following its establishment. Here, we examined expansion patterns at different spatial scales in urban areas to clarify how R. flavipes spread in France. Based on our analyses of phylogeography and population genetics, results suggest a scenario of successive introductions into the Charente-Maritime region, on the Atlantic Coast. Two major expansion fronts formed: one that spread toward the northeast and the other toward the southeast. At the regional scale, different spatial and genetic distribution patterns were observed: there was heterogeneity in Île-de-France and aggregation in Centre-Val de Loire. At the local scale, we found that our three focal urban sites each formed a single large colony that contained several secondary reproductives. Our findings represent a second step in efforts to reconstruct termite’s invasion dynamics. They also highlight the role that may have been played by the French railway network in transporting termites over long distances.