No abstract

In bats, sexual segregation has been described in relation to differential use of roosting and foraging habitats. It is possible that variation may also exist between genders in the use of different prey types. However, until recently this idea was difficult to test owing to poorly resolved taxonomy of dietary studies. Here, we use high-throughput sequencing to describe gender-related variation in diet composition of the European free-tailed bat (Tadarida teniotis), while controlling for effects of age and season. We analysed guano pellets collected from 143 individuals mist-netted from April to October 2012 and 2013, in northeast Portugal. Moths (Lepidoptera; mainly Noctuidae and Geometridae) were by far the most frequently recorded prey, occurring in nearly all samples and accounting for 96 out of 115 prey taxa. There were significant dietary differences between males and females, irrespective of age and season. Compared to males, females tended to consume larger moths and more moths of migratory behaviour (e.g. Autographa gamma). Our study provides the first example of gender-related dietary variation in bats, illustrating the value of novel molecular tools for revealing intraspecific variation in food resource use in bats and other insectivores.

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Farmland abandonment and the accompanying natural succession are largely perceived as unwanted amongst many European conservationists due to alleged negative effects on biodiversity levels. Here, we test this assumption by analysing alpha, beta and gamma diversity patterns of macro-moth communities in habitats on an ecological succession gradient, from extensively managed meadows to scrub-encroached and wooded sites. Macro-moths were light-trapped at 84 fixed circular sampling sites arranged in a semi-nested design within the National Park of Peneda-Gerês, NW-Portugal. In total, we sampled 22825 individuals belonging to 378 species. Alpha, beta and gamma diversity patterns suggest that farmland abandonment is likely to positively affect both overall macro-moth diversity and forest macro-moth diversity, and to negatively affect species diversity of non-forest macro-moth species. Our results also show that spatial habitat heterogeneity is important to maintain gamma diversity of macro-moths, especially for rare non-forest species and habitat specialists.

Increasing evidence for global insect declines is prompting a renewed interest in the survey of whole insect communities. DNA metabarcoding can contribute to assessing diverse insect communities over a range of spatial and temporal scales, but efforts are still needed to optimize and standardize procedures. Here, we describe and test a methodological pipeline for surveying nocturnal flying insects, combining automatic light traps and DNA metabarcoding. We optimized laboratory procedures and then tested the methodological pipeline using 12 field samples collected in northern Portugal in 2017. We focused on Lepidoptera to compare metabarcoding results with those from morphological identification, using three types of bulk samples produced from each field sample (individuals, legs, and the unsorted mixture). The customized trap was highly efficient at collecting nocturnal flying insects, allowing a small team to operate several traps per night, and a fast field processing of samples for subsequent metabarcoding. Morphological processing yielded 871 identifiable individuals of 102 Lepidoptera species. Metabarcoding of the “mixture” bulk samples detected 528 taxa, most of which were Lepidoptera, Diptera, and Coleoptera. There was a reasonably high matching in community composition between morphology and metabarcoding when considering the “individuals” and “legs” bulk samples, with few errors mostly associated with morphological misidentification of small and often degraded microlepidoptera. Regarding the “mixture” bulk sample, metabarcoding identified nearly four times more Lepidoptera species than morphological examination, mostly due to the recovery of DNA from very damaged specimens that could not be visually identified, but also thanks to the retention of body parts and DNA of specimens removed for the “individuals” and “legs” bulks. Our study provides a methodological metabarcoding pipeline that can be used in standardized surveys of nocturnal flying insects. Our approach efficiently collects highly diverse taxonomic groups such as nocturnal Lepidoptera that are poorly represented when using Malaise traps and other widely used field methods.