Maternal care and juvenile feeding in a hyperiid amphipod (Oxycephalus clausi Bovallius, 1887) in association with gelatinous zooplankton

Planktonic associations between medusae (classes Scyphozoa and Hydrozoa) and epifaunal crustaceans

“…In conclusion, the overall best sampling results come from observation-first methodologies such as collection by-hand while snorkeling and diving, as in Mazda et al (2019) , ROV/HOV in situ underwater photography, as employed by Gasca, Hoover & Haddock (2015) , or imaging and supplemental trawling as in Greer et al (2017) . Obtaining underwater pictures of medusae and epibiont is crucial to the understanding of the associate placement in relation to host and its behavior.…”

“…Within and upon the host, juvenile crustaceans were often coexisting with adult forms. Eighty-one of the associations include juveniles (excluding megalopae, eggs, and copepodites), sometimes embedded in host tissue ( Towanda & Thuesen, 2006 ; Browne, 2015 ; Yusa et al, 2015 ; Browne, Pitt & Norman, 2017 ; Mazda et al, 2019 ). The presence of eggs and ovigerous females was reported in 39 cases from 23 different species.…”

“…Only one study provides an indication of how nuanced the relationship between gelatinous zooplankton hosts and epibionts may be; 6 years of monthly observation showed that single adult females of the amphipod Oxycephallus clausi (Bovallius, 1887) had a broad range of gelatinous hosts, but shifted to primarily Ocyropsis fusca (Rang, 1827), a lobate ctenophore, during brood release ( Mazda et al, 2019 ). While ctenophores are not the focus of this review, it shows that the nature of interactions may change during the crustacean lifecycle.…”

“…These sorts of long-term analyses are hard to pursue, but provide a fascinating look at the range of information that can be collected with observational methods. Uneven sex ratios, such as those seen in the case of Oxycephallusclausi (97% female), are present across many associations ( Condon & Norman, 1999 ; Filho et al, 2008 ; Oliva, Maffet & Laudien, 2010 ; Mazda et al, 2019 ). The most common explanation for this higher ratio of females and often ovigerous females is use of scyphozoan and hydrozoan hosts primarily as nursery habitat for movement and protection of juveniles ( Gonçalves et al, 2016 ; Gonçalves et al, 2017 ; Mazda et al, 2019 ).…”

“…Uneven sex ratios, such as those seen in the case of Oxycephallusclausi (97% female), are present across many associations ( Condon & Norman, 1999 ; Filho et al, 2008 ; Oliva, Maffet & Laudien, 2010 ; Mazda et al, 2019 ). The most common explanation for this higher ratio of females and often ovigerous females is use of scyphozoan and hydrozoan hosts primarily as nursery habitat for movement and protection of juveniles ( Gonçalves et al, 2016 ; Gonçalves et al, 2017 ; Mazda et al, 2019 ). Potential territoriality in some females, like those of P. paivai , may help ensure more resources for their brood, and is in line with other symbiont crustaceans ( Baeza et al, 2017 ).…”