ADVANCEMENTS IN TROPHIC ANALYSIS: A METABARCODING APPROACH TO THE DIET OF BATS

ADVANCEMENTS IN TROPHIC ANALYSIS: A METABARCODING APPROACH TO THE DIET OF BATS

Vanessa Mata | August 1, 2016 | 17th International Bat Research Conference, Durban, South Africa

Traditional diet analysis of bats has been based on visual identification of hard undigested parts of prey insects. These are usually small and have a very low taxonomic resolution. Recent molecular techniques capable of generating large quantities of data (e.g. metabarcoding) have come to revolutionize diet analysis, allowing a species level identification of prey. This has brought unprecedented resolution into bats’ trophic interactions, but has also opened a wide of methodological questions regarding sampling design. In here we present an example of how metabarcoding can shine new light on the ecology of bats, and explore some preliminary results on the consequences of the sampling methods used in molecular dietary assessments. We used high throughput sequencing to assess gender-variation in diet of European free-tailed bats (Tadarida teniotis), by analyzing guano pellets from 143 individuals mist-netted in north-east Portugal. Our results showed no marked temporal differences in diet composition, but resource partitioning was found between males and females, independently of bat age, with females consuming larger prey and more moths with migratory behavior, thus illustrating the value of novel molecular tools for revealing intraspecific variation in food resource use in bats and other insectivores. Taking advantage on the large number of T. teniotis guano samples collected, we assessed how the number of pellets used per individual, the fact whether DNA extraction was done in separate or by pooling several pellets, and the number of PCR replicates done, affected the outcome of each individual’s diet. This should have implications on the sample size needed for molecular studies, but also on the best cost-efficient method to understand the diet of a species.