Lopez-Vaamonde, C. | Search bioRxiv

bioRxiv2021

Tracing the invasion of a leaf-mining moth in the Palearctic through DNA barcoding of historical herbaria

Historical herbaria are valuable sources of data in invasion biology. Here we study the invasion history of the lime leaf-miner, Phyllonorycter issikii, by surveying over 15 thousand herbarium specimens of limes (Tilia spp.) collected in the Palearctic during last 253 years (1764-2016). The majority of herbarium specimens with the pests mines (89%) originated from East Asia (1859-2015), whereas remaining 11% of specimens with the mines came from Europe, European Russia and Western Siberia (1987-2015). These results support the hypothesis of a recent Ph. issikii invasion from Eastern to Western Palearctic. Single molecule real-time sequencing of the COI barcode region of 93 archival larvae and pupae (7-162 years old) dissected from the mines on historical herbaria allowed to distinguish between Ph. issikii and Ph. messaniella, a polyphagous species rarely feeding on Tilia, which mines were found in herbarium from Europe dated by 1915-1942. We discovered 25 haplotypes of Ph. issikii, of which 16 haplotypes were present solely in East Asia, and revealed wide distribution of the species in China. Six haplotypes shared between Eastern and Western Palearctic suggest the contribution of Ph. issikii populations from the Russian Far East, China and Japan to the westward invasion.

ecology↗

bioRxiv2021

Climate-induced forest dieback drives compositional change in insect communities that is concentrated amongst rare species

Marked decline in insect species richness, abundance and biomass have recently been quantified in Europe. We metabarcoded 224 Malaise-trap samples to investigate whether drought-induced forest dieback and subsequent salvage logging have an impact on flying insects (ca. 3000 insect species) in silver fir Pyrenean forests. We found no evidence that climate-induced forest dieback impacted species richness of flying insects but revealed compositional turnover patterns consistent with those seen during natural forest succession, given that the key covariates explaining compositional variation were canopy openness versus microhabitat diversity and deadwood amount at local and landscape scales, respectively. Importantly, most change was driven by rare species. In contrast, observed levels of salvage logging did not explain change in species richness or composition. Hence, although forest dieback appears to cause changes in species assemblages mimicking natural forest succession, it also increases the risk of catastrophic loss of rare species through homogenization of environmental conditions.

ecology↗