Prey Capture Ecology of the Cubozoan Carukia barnesi

Abstract

Adult Carukia barnesi medusae feed predominantly on larval fish; however, their mode of prey capture seems more complex than previously described. Our findings revealed that during light conditions, this species extends its tentacles and ‘twitches’ them frequently. This highlights the lure-like nematocyst clusters in the water column, which actively attract larval fish that are consequently stung and consumed. This fishing behavior was not observed during dark conditions, presumably to reduce energy expenditure when they are not luring visually oriented prey. We found that larger medusae have longer tentacles; however, the spacing between the nematocyst clusters is not dependent on size, suggesting that the spacing of the nematocyst clusters is important for prey capture. Additionally, larger specimens twitch their tentacles more frequently than small specimens, which correlate with their recent ontogenetic prey shift from plankton to larval fish. These results indicate that adult medusae of C. barnesi are not opportunistically grazing in the water column, but instead utilize sophisticated prey capture techniques to specifically target larval fish.

Early Life History of the ‘Irukandji’ Jellyfish Carukia barnesi

“…Cubozoans have been shown to be sophisticated in many areas of their ecology from possessing complex vision capabilities [ 38 – 40 ], prey capture techniques [ 41 ], behavioural patterns [ 42 , 43 ], and complex venoms [ 19 , 28 , 44 ]. Not surprisingly, the life cycle of cubozoans also have many species specific complexities [ 2 , 3 , 6 , 7 , 10 , 13 – 15 ].…”

Fluorescent proteins function as a prey attractant: experimental evidence from the hydromedusa Olindias formosus and other marine organisms

“… Purcell (1980) was among the first to suggest that siphonophore tentacles (Cnidaria, Hydrozoa) sometimes bore lures which were used for aggressive mimicry, and medusae have been suggested to use their tentacles in a similar manner ( Larson, 1986 ; Courtney et al, 2015 ). Although these examples do not involve fluorescence, we have previously found siphonophores with lure-like tentilla that are either fluorescent ( Pugh and Haddock, 2010 ) or bioluminescent ( Haddock et al, 2005 ).…”

Characterising Functional Venom Profiles of Anthozoans and Medusozoans within Their Ecological Context

“…An altered venom protein profile in the absence of nematocyst variation also occurs in the jellyfish Carukia barnesi [64,65]. Augmentation of neckchieves, nematocyst bands within tentacles that are postulated to function as a prey attractant, is observed in mature C. barnesi, as is an increase in frequency of twitching of this structure to actively lure fish [65][66][67]. These morphological changes provide preliminary evidence that a difference in predatory behaviour accompanies a shift in venom composition during the maturation of some cubozoan species.…”