Abstract
Understanding how non‐native scyphozoan jellyfish interact with native communities provides insights into the ecological processes structuring their populations. Aurelia coerulea is a problematic invasive species, with no known predators of the polyp stage outside its native range. Austraeolis ornata is a potential predator of A. coerulea polyps, but little is known about its biology and ecology. Both species inhabit shallow coastal waters across southern Australia, suggesting that interactions between them are likely and could influence population dynamics. Here, we tested the hypothesis that A. ornata recognizes A. coerulea as prey and exhibits high predation potential on introduced polyp populations. We conducted four experiments to: (1) determine whether nudibranchs can detect and locate jellyfish polyps as prey, (2) test whether nudibranchs show any preference between non‐native jellyfish polyps and a confirmed native prey, (3) assess the relationship between nudibranch size and the number of jellyfish polyps consumed, and (4) evaluate whether nudibranchs can survive and grow on an exclusive diet of jellyfish polyps. Nudibranchs located their prey and began feeding within 14 ± 6 min, showing clear predatory behavior, and consumed up to 197 jellyfish polyps predator −1 day −1 , with feeding rate strongly correlated with body size. Furthermore, nudibranchs grew an average of 9.8 ± 5.2 mm in length and 334.7 ± 184.8 mg in weight over 3 weeks, confirming their ability to survive and sustain growth on an exclusive diet of jellyfish polyps. These findings suggest that A. ornata recognizes A. coerulea polyps as prey and could likely play an important ecological role in regulating introduced A. coerulea polyp populations in southern Australia.