Feeding ecology and niche segregation of the spider crab Libinia ferreirae (Decapoda, Brachyura, Majoidea), a symbiont of Lychnorhiza lucerna (Cnidaria, Scyphozoa, Rhizostomeae)

Unveiling the dynamics of the spider crab Libinia ferreirae, through reproductive and population characteristics on the south-eastern coast of Brazil

“…We believe that the OFs of L. ferreirae peaked in the autumn in order to maximize their reproductive success, as there is higher food availability during this season. During this time of the year, the SACW usually recedes and there is intense suspension of sediments, causing a carriage with particulate organic matter generated in the previous period and, although crabs feed on bivalves and gastropods, they also consume the organic matter in the sediment (Gonçalves et al ., 2020). The mechanisms used by L. ferreirae to expand reproductive success in the present study were probably successful since there was ‘effective spawning’ in the region.…”

Predation of portunid crabs Callinectes sapidus and Callinectes ornatus (Crustacea, Decapoda) on the medusa Lychnorhiza lucerna (Cnidaria, Scyphozoa)

“…In some cases, these symbionts also provide benefits to their hosts, by cleaning jellyfish ectoparasites (Towanda and Thuesen, 2006). In contrast, some studies have suggested that jellyfishes are consumed by their symbionts (D'Ambra et al, 2015) or that symbionts ingest food particles captured by the jellyfish (Gonçalves et al, 2020). Brachyuran crabs are often found with scyphomedusae in coastal and estuarine areas (Farr, 1978;Moyano et al, 2012;Ates, 2017;Gonçalves, et al 2020).…”

“…In contrast, some studies have suggested that jellyfishes are consumed by their symbionts (D'Ambra et al, 2015) or that symbionts ingest food particles captured by the jellyfish (Gonçalves et al, 2020). Brachyuran crabs are often found with scyphomedusae in coastal and estuarine areas (Farr, 1978;Moyano et al, 2012;Ates, 2017;Gonçalves, et al 2020). These symbioses usually involve the megalopae or young crabs, but adults were also reported on top of the jellyfish bells.…”

“…Information on the possible trophic role of these symbiotic relationships is scattered or unavailable in many cases. Moyano et al (2012) reviewed 28 studies on associations involving 18 jellyfish and nine crab species; only nine studies provided evidence of predation on the jellyfish hosts, ranging from direct observations of predation in situ (Farr, 1978), laboratory experiments (Esser et al, 2004), analysis of crab gut contents (Gonçalves et al, 2020), to trophic markers such as stable isotopes (Mancinelli et al, 2017). Although these studies may reveal an important trophic link, the potential damage these symbionts may cause and whether jellyfish populations can be affected by these crabs remain unsolved.…”

“…The extent of the damage caused by decapods feeding on jellyfishes can be varied. For spider crabs of the genus Libinia, it has been suggested that the damage to the hosts is not substantial and that nematocysts of L. lucerna found in the gut contents could have been incidentally ingested along with prey captured by the jellyfish (Moyano et al, 2012;Gonçalves et al, 2020). In contrast, decapods such as Carcinus maenas, Crangon crangon, and Pagurus bernhardus were able to actively capture and consume comb jellyfish in laboratory experiments (Esser et al, 2004) or in the field (Ramussen, 1973;Farr, 1978).…”