Scyphozoan jellyfish provide short-term reproductive habitat for hyperiid amphipods in a temperate near-shore environment

Abstract

Hyperiid amphipods (Order Amphipoda, Suborder Hyperiidea) are known to infest gelatinous zooplankton. However, the temporal backdrop to these associations is less clear, given that data are often gathered during discrete sampling events rather than over time. In general, hyperiids are considered to be pelagic: however, for individuals associated with metagenic jellyfishes in temperate shallow shelf seas, this may not always be the case, as the majority of their gelatinous hosts are present in the water column from spring to the onset of autumn. Here, we explored the temporal patterns of colonisation and overall duration of the association between Hyperia galba and 3 scyphozoan jellyfish species (Aurelia aurita, Cyanea capillata and C. lamarckii) in a temperate coastal system (Strangford Lough, Northern Ireland) during 2010 and 2012. Concomitantly, we used carbon and nitrogen stable isotope ratios to examine whether hyperiid infestation represented a permanent association with their host or was part of a more complex life history. We found that jellyfish were colonised by H. galba ca. 2 mo after they are first observed in the lough and that H. galba reached 100% prevalence in the different jellyfish species shortly before the medusae of each species disappeared from the water column. It is possible that some jellyfish overwintered in deeper water, prolonging the association between H. galba and their hosts. However, all the medusae sampled during the spring and early summer (whether they were newly emerged or had overwintered from the previous season) were not infected with hyperiids, suggesting that such behaviour was uncommon or that individuals had become dissociated from their host during the winter. Further evidence of temporary association came from stable isotope data, where δ 13 C and δ 15 N isotope ratios were indicative of feeding outside of their host prior to jellyfish colonisation. In combination, these findings suggest alternating habitat associations for H. galba, with the amphipods spending the majority of the year outside of the 3 scyphozoan species considered here.

Trophic relationships between the large scyphomedusa Chrysaora plocamia and the parasitic amphipod Hyperia curticephala

“…Considering that pelagic phytoplankton, macroalgae and benthic microalgae are the main sources of primary production in this area (Reddin et al 2015) and the fact that C. plocamia (Ceh et al 2015) and hyperiid amphiods (Fleming et al 2014) may use benthic resources, samples of macroalgae, particulate organic matter (POM) and benthic algae/biofilm were collected from subtidal locations on the Mejillones peninsula adjacent to Mejillones Bay to include them as potential energy sources in our analysis. Epilithic biofilm was scraped from rocks using a metal spatula, a 5 l water sample was collected for POM, and fronds of the dominant brown alga (Lessonia nigrescens) were collected, with tissue taken from frond areas of recent growth.…”

“…Benthic sources were included following a recent report of their contribution to Hyperia in a coastal system in the North-East Atlantic (Fleming et al 2014) as well as our interest in the potential shift in host habitat use with size. δ 13 C and δ 15 N values for H. curticephala were adjusted for trophic fractionation (isotopic difference between a consumer and their prey) using three different trophic enrichment factors (TEFs).…”

“…Assessing trophic relationships between hyperiid parasites and their host using gut content analysis is challenging due to the small size of hyperiids and their prey. According to Laval (1980), hyperiids may directly consume host tissues or their prey, depending on host life stage and changes in hyperiid density, a view supported by a recent study using stable isotopes (Fleming et al 2014). Therefore, assessment of trophic function should integrate this spatial-temporal variability in food sources for both parasitic hyperiids and their hosts.…”

Quacks snack on smacks: mallard ducks (<i>Anas platyrhynchos</i>) observed feeding on hydrozoans (<i>Velella velella</i>)

“…Lynam & Brierley 2007, D Ambra et al 2014, Fleming et al 2014. Moreover, aside from specialised obligate gelativores such the leatherback turtle Dermochelys coriacea (Vandelli, 1761) (Brongersma 1969), growing evidence suggests that a vast array of taxa also consume gelatinous prey periodically (see reviews : Arai 2005, Ates 2017 (Hoving & Haddock 2017) and other gelatinous species (e.g.…”

Stable isotope analysis reveal hidden reliance on scyphozoan jellyfish in a commensal fish: editorial comment on the feature article by D’Ambra et al.

“…The study by D'Ambra and her colleagues joins a limited pool of isotopic studies that also show assimilation of jellyfish host tissues by of commensal crabs and amphipods (Towanda and Thuesen 2006;Fleming et al 2014). As such, the prevailing view that commensal taxa primarily use their hosts as habitat is clearly due for some rethought.…”