Potential distribution and ecological dimensions of four species in the genus Physopelta(Hemiptera:Largidae)

Our knowledge of the identity and distribution of most species on earth is remarkably poor. Species in hotspots tend to be scarce within their range which increases their probability of extinction. In this study, we used ecological niche modeling （ENM） to estimate dimensions of realized niches of 4 species that are totally （Physopelta robusta St^l and Physopelta slanbuschii Fabricius） or partially （Physopelta cincticollis StS,1 and Physopelta quadriguttata Bergroth） distributed in the Indo-Myanmar and South Central China hotspot, and predicted additional sites where they might be found. Our findings suggest that the range of the 4 species could extend beyond their presently known distributions, which might be useful for future field surveys. Niche overlap was modeled between the 4 species, with R slanbuschii and R robusta showing more tolerance to temperature and P quadriguttata and P. slanbuschii more tolerance to precipitation. This study presents one more case study which highlights the ecological approach for taxonomic study in biodiversity conservation, especially of poorly, little known, and localized endemic species.

Northwestward range expansion of the bumblebee Bombus haematurus into Central Europe is associated with warmer winters and niche conservatism

Species range expansions are crucial for understanding niche formation and the interaction with the environment.Here,we studied the bumblebee Bombus haematurus Kriechbaumer,1870,a species historically distributed from northern Serbia through northern Iran which has very recently started expanding northwestward into Central Europe without human-mediated dispersal(i.e.,it is a natural spread).After updating the global distribution of this species,we investigated if niche shifts took place during this range expansion between newly colonized and historical areas.In addition,we have explored which climatic factors may have favored the natural range expansion of the species.Our results indicated that Bombus haematurus has colonized large territories in 7 European countries outside the historical area in the period from the 1980s to 2018,a natural expansion over an area that equals 20%of the historical distribution.In addition,this bumblebee performs generalism in flower visitation and it occurs in different habitats,although a preference for forested areas clearly emerges.The land-use associated with the species in the colonized areas is similar to the historical distribution,indicating that no major niche shifts occurred during the spread.Furthermore,in recently colonized localities,the range expansion was associated with warming temperatures during the winter and also during both queen overwintering and emergence phases.These findings document a case of natural range expansion due to environmental change rather than due to niche shifts,and specifically they suggest that warmer winters could be linked to the process of natural colonization of new areas.