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Niche partitioning studies are essential to understand the mechanisms that allow ecologically similar species to coexist. The Rhone streber (Zingel asper) and the European bullhead (Cottus gobio) are both benthic riverine fishes that consume macroinvertebrates. Both species are protected under European legislature. We focused on trophic niche partitioning between these species, as sufficient access to trophic resources is an important requirement for long-term coexistence. We used a combination of faeces metabarcoding dietary data and prey community data to evaluate dietary overlap, trophic niche variation and dietary preferences. Sampling was performed in three sites along the Durance River (France). Both species consumed a wide range of macroinvertebrates but neither C. gobio nor Z. asper selected the most abundant taxa (chironomids and simuliids). Both species selected larger mayfly (Baetis and Ecdyonurus) and caddisfly (Hydropsyche) taxa. Dietary overlap was generally high but declined when large mayflies were rare. Contrasting secondary prey preferences and trophic niche variation may allow these species to exploit the same preferred mayflies in periods of abundance and to avoid competition during resource scarcity. We propose that dietary partitioning may support the coexistence of these two ecologically similar, benthic predators.

Niche partitioning studies are essential to understand the mechanisms that allow ecologically similar species to coexist. The Rhone streber (Zingel asper) and the European bullhead (Cottus gobio) are both benthic riverine fishes that consume macroinvertebrates. Both species are protected under European legislature. We focused on trophic niche partitioning between these species, as sufficient access to trophic resources is an important requirement for long-term coexistence. We used a combination of faeces metabarcoding dietary data and prey community data to evaluate dietary overlap, trophic niche variation and dietary preferences. Sampling was performed in three sites along the Durance River (France). Both species consumed a wide range of macroinvertebrates but neither C. gobio nor Z. asper selected the most abundant taxa (chironomids and simuliids). Both species selected larger mayfly (Baetis and Ecdyonurus) and caddisfly (Hydropsyche) taxa. Dietary overlap was generally high but declined when large mayflies were rare. Contrasting secondary prey preferences and trophic niche variation may allow these species to exploit the same preferred mayflies in periods of abundance and to avoid competition during resource scarcity. We propose that dietary partitioning may support the coexistence of these two ecologically similar, benthic predators.

Seastars are opportunistic predators that feed on bivalve molluscs and other invertebrates. In a dynamic system like the sublitoral of the rocky shores near Concarneau (South Brittany, France) there are several parameters possibly influencing the choice of prey like the tides, abundance of seastars as well as abundance of the different prey species. In two different experimental setups (five aquaria with one individual each and two aquaria with about 25 individuals each) we investigated the prey preferences of Marthasterias glacialis. We wanted to find out whether there are any prey preferences at all and if so, whether these preferences were depending on individual predator size and on intraspecific competition. The sea stars were offered 6 different prey species: Magallana gigas, Patella spec., Mytilus edulis, Phorcus lineatus, Littorina obtusata and Chthalamus spec. The results show that Mytilus edulis and Patella spec. are the most preferred prey species. In addition, our observations suggest that intraspecific competition has an influence on prey choice with a preference for organisms to be subdued and eaten in a shorter amount of time. Concluding we can say that under laboratory conditions the sea star M. glacialis shows prey preferences. Those are slightly depending on individual size and intraspecific competition. Preceding work (Gianguzza et al., 2016) supports to expect those findings to be at least in parts applicable to the natural habitat of M. glacialis., Seesterne sind opportunistische Raubtiere, die sich von Muscheln und anderen Wirbellosen ernähren. In einem dynamischen System wie dem Sublitoral der felsigen Küste bei Concarneau (Südbretagne, Frankreich) gibt es mehrere Parameter, die die Wahl der Beute beeinflussen können, wie die Gezeiten, die Häufigkeit von Seesternen sowie die Häufigkeit der verschiedenen Beutearten. In zwei verschiedenen Versuchsanordnungen (fünf Aquarien mit je einem Individuum und zwei Aquarien mit jeweils ca. 25 Individuen) haben wir die Beutepräferenzen von Marthasterias glacialis untersucht. Wir wollten herausfinden, ob es überhaupt Beutepräferenzen gibt und wenn ja, ob diese Präferenzen von der individuellen Räubergröße und von intraspezifischer Konkurrenz abhängen. Den Seesternen wurden 6 verschiedene Beutearten angeboten: Magallana gigas, Patella spec., Mytilus edulis, Phorcus lineatus, Littorina obtusata und Chthalamus spec. Die Ergebnisse zeigen, dass Mytilus edulis und Patella spec. die am meisten bevorzugten Beutetiere sind. Darüber hinaus deuten unsere Beobachtungen darauf hin, dass die intraspezifische Konkurrenz einen Einfluss auf die Beutewahl hat, wobei Organismen bevorzugt werden, die in kürzerer Zeit unterdrückt und gefressen werden können. Zusammenfassend lässt sich sagen, dass der Seestern M. glacialis unter Laborbedingungen Beutepräferenzen zeigt. Diese hängen leicht von der individuellen Größe und der intraspezifischen Konkurrenz ab. Vorangegangene Arbeiten (Gianguzza et al., 2016) lassen erwarten, dass diese Ergebnisse zumindest teilweise auf den natürlichen Lebensraum von M. glacialis übertragbar sind., Peer Reviewed

Seastars are opportunistic predators that feed on bivalve molluscs and other invertebrates. In a dynamic system like the sublitoral of the rocky shores near Concarneau (South Brittany, France) there are several parameters possibly influencing the choice of prey like the tides, abundance of seastars as well as abundance of the different prey species. In two different experimental setups (five aquaria with one individual each and two aquaria with about 25 individuals each) we investigated the prey preferences of Marthasterias glacialis. We wanted to find out whether there are any prey preferences at all and if so, whether these preferences were depending on individual predator size and on intraspecific competition. The sea stars were offered 6 different prey species: Magallana gigas, Patella spec., Mytilus edulis, Phorcus lineatus, Littorina obtusata and Chthalamus spec. The results show that Mytilus edulis and Patella spec. are the most preferred prey species. In addition, our observations suggest that intraspecific competition has an influence on prey choice with a preference for organisms to be subdued and eaten in a shorter amount of time. Concluding we can say that under laboratory conditions the sea star M. glacialis shows prey preferences. Those are slightly depending on individual size and intraspecific competition. Preceding work (Gianguzza et al., 2016) supports to expect those findings to be at least in parts applicable to the natural habitat of M. glacialis., Seesterne sind opportunistische Raubtiere, die sich von Muscheln und anderen Wirbellosen ernähren. In einem dynamischen System wie dem Sublitoral der felsigen Küste bei Concarneau (Südbretagne, Frankreich) gibt es mehrere Parameter, die die Wahl der Beute beeinflussen können, wie die Gezeiten, die Häufigkeit von Seesternen sowie die Häufigkeit der verschiedenen Beutearten. In zwei verschiedenen Versuchsanordnungen (fünf Aquarien mit je einem Individuum und zwei Aquarien mit jeweils ca. 25 Individuen) haben wir die Beutepräferenzen von Marthasterias glacialis untersucht. Wir wollten herausfinden, ob es überhaupt Beutepräferenzen gibt und wenn ja, ob diese Präferenzen von der individuellen Räubergröße und von intraspezifischer Konkurrenz abhängen. Den Seesternen wurden 6 verschiedene Beutearten angeboten: Magallana gigas, Patella spec., Mytilus edulis, Phorcus lineatus, Littorina obtusata und Chthalamus spec. Die Ergebnisse zeigen, dass Mytilus edulis und Patella spec. die am meisten bevorzugten Beutetiere sind. Darüber hinaus deuten unsere Beobachtungen darauf hin, dass die intraspezifische Konkurrenz einen Einfluss auf die Beutewahl hat, wobei Organismen bevorzugt werden, die in kürzerer Zeit unterdrückt und gefressen werden können. Zusammenfassend lässt sich sagen, dass der Seestern M. glacialis unter Laborbedingungen Beutepräferenzen zeigt. Diese hängen leicht von der individuellen Größe und der intraspezifischen Konkurrenz ab. Vorangegangene Arbeiten (Gianguzza et al., 2016) lassen erwarten, dass diese Ergebnisse zumindest teilweise auf den natürlichen Lebensraum von M. glacialis übertragbar sind., Peer Reviewed

© 2020 Elsevier Ltd Like human groups, carnivores are able to act on the same faunal accumulation and generate important bone assemblages with their prey remains. In addition, both predators can share the same habitable areas and alternate their occupations, producing the well-known palimpsest at archaeological sites. As a discipline, taphonomy helps us understand the formation of these sites and allows us to identify what occurred before and after the burial of the remains. In order to make an accurate taphonomic interpretation, knowledge of the carnivore ethology is necessary to understand the way that bone accumulations originate and to make inferences about their relationship with human behaviour or other living beings of the environment. In this work, a first taphonomic approach concerning the faunal assemblage of unit 2 of Tritons Cave (Lleida, Catalonia) has been carried out. This unit is characterized by the prevailing presence of the Iberian ibex (Capra pyrenaica) and, to a lesser extent, the brown bear (Ursus arctos) and cave bear (Ursus spelaeus). The survival profile of goats, the alterations observed on the bones, and the consumption patterns seem to indicate that the main agent accumulator is the leopard (Panthera pardus); nevertheless, the occasional intrusion and secondary activity of other predators, including hominins, cannot be ruled out. The presence of ursids and the alterations on their bones seem to be related to natural deaths and subsequent carnivore activity, which indicates the high complexity in the assemblage formation. The identification of the leopard as a main taphonomic agent sheds light about these kinds of dens, establishing guidelines to differentiate bone accumulations produced by other carnivores as well as the criteria to identify