Otter diet and prey selection in a recently recolonized area assessed using microscope analysis and DNA barcoding

Hystrix, the Italian Journal of Mammalogy

article

Fabio Marcolin¹  Francesca Iordan²  Elisabetta Pizzul³  Alberto Pallavicini³  Valentina Torboli³  Chiara Manfrin³  Lorenzo Quaglietta⁴ 

[1] Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa;Therion Research Group;Department of Life Sciences, University of Trieste;CIBIO/InBio – Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto

关键词: diet;    feeding ecology;    DNA barcoding;    Lutra lutra;    otter;    prey selection;   

DOI  :  10.4404/hystrix-00260-2019

学科分类：社会科学、人文和艺术（综合）

来源: Associazione Teriologica Italiana

【 摘 要 】

Ecologists traditionally investigate the feeding ecology of vertebrates by visual identification ofprey in their scats using a microscope. This analysis, however, presents some pitfalls, such as poorprey identification at genus/species level. DNA barcoding is an alternative to the traditional dietanalysis, recently applied to investigate the diet of several vertebrates. It allows the identificationof cryptic or not-recognizable prey portions basing their identification on the analysis of conservedDNA fragments. Here, we combined microscope analysis with DNA barcoding to investigate thediet of the Eurasian otter (Lutra lutra) in an area recently recolonized by the species, in the surroundings of Tarvisio, NE Italy. We collected 102 spraints and analysed all of them at microscope.A random subsample (N=50) was then analysed through DNA barcoding, via amplification of theV9 region of the SSU 18S-rDNA 18S gene. Furthermore, we assessed seasonal variation in otter diet and whether otters select certain salmonids size classes, to identify potential conflict withanglers. According to the microscope analysis, otters ate primarily fish (salmonids and Europeanbullhead), secondarily amphibians and, more rarely, crayfish, both annually and seasonally. DNAbarcoding analysis confirmed the microscope results, attributing some salmonids sequences to thebrown trout (Salmo trutta). The lack of potential prey species reference sequences in the GenBankdatabase hampered us in identifying the other taxa found in the spraints at more informative levels. Consumed salmonids and bullheads were of small size. In particular, otters selected salmonidssize class of 100 mm, which is much smaller than the minimum catchable size for angling. Overall,our study confirms DNA barcoding potential for otter diet analyses, highlighting the need of additional markers to improve molecular prey identification and suggesting that otters do not constitutea significant threat to anglers in the area.

【 授权许可】

CC BY-NC