TROPHIC GROUPS IN A MEDITERRANEAN BAT COMMUNITY: ARE ECHOLOCATION AND FORAGING BEHAVIOR REALLY IMPORTANT?
Vanessa Mata (CIBIO-InBIO) | July 30, 2019 | 18th International Bat Research Conference, The Slate, Phuket, Thailand
Predator-prey interactions forge the behaviour and ecology of all organisms and are crucial in structuring ecological communities. In bats, several studies have emphasized the role of species morphology, echolocation, and foraging behaviour in prey acquisition and have tried to group bats accordingly in guilds. However, due to practical difficulties in studying entire communities and the constraints of morphology-based diet analysis, it is not clear how these guilds actually correlate to diet. To better understand this question, we used DNA metabarcoding to assess the diet of an insectivorous Mediterranean bat community located in Northeast Portugal composed by 19 different species.
Bat droppings were collected from 486 individual bats and DNA was extracted and amplified from 1206 individual pellets (up to three per bat). We used a canonical and ecological network analysis to assess the dietary guilds. Bats were structured in 4-5 diet groups, three of which were very distinct and fed on either noctuid moths, crickets, or spiders, respectively. The fourth and fifth groups were mainly characterized by not feeding on these taxa and ingesting more coleoptera, diptera and hemiptera. None of the diet groups corresponded to previously suggested echolocation or foraging guilds, with the exception of Myotis myotis, the only ground gleaning bat in our community, which formed a guild on its own. For the first time, we provide empirical evidence for the existence of dietary guilds in Mediterranean insectivorous bat communities and show that these do not correlate to previously proposed guilds based on echolocation signal or foraging behaviour.