Research Press Release

Ecology: Invasive comb jellies cannibalize their young after decimating prey

Communications Biology

May 8, 2020

Comb jellies in the western Baltic Sea cannibalize their own larvae when food is scarce, according to a paper published this week in Communications Biology. This finding may explain the success of this invasive species, and help the design of conservation strategies to control its spread.

The invasive warty comb jelly Mnemiopsis leidyi is a marine predator native to the western Atlantic, although it has become widespread in Eurasian waters since its introduction in the 1980s. These jellies compete with fish and fish larvae and can cause a cascading effect on crucial planktonic food webs and disrupt commercial fisheries. Although comb jelly populations exhibit boom-and-bust-like dynamics, it is unknown how this species maintains rapid population growth in Northern Eurasian waters, where it lives through long periods of prey scarcity.

Jamileh Javidpour and colleagues sampled comb jellies in the Kiel Fjord on the eastern side of Germany. They observed that when the abundance of copepods (the jellies’ main prey) collapsed, the comb jelly larvae would collapse soon after, but not the adults. To understand why this happened, the authors studied comb jellies in the lab and found that after depleting the copepod prey, the comb jellies cannibalized their own larvae. The authors argue that by creating massive later-summer blooms, these jellies virtually decimate their prey species — outcompeting their fellow predators — and then shift to cannibalism to build nutrient reserves for periods of low food availability.

This research may aid in devising effective strategies to control this prolific invasive species as well as provide insight into the evolutionary origins of cannibalism in the animal kingdom.

doi:10.1038/s42003-020-0940-2

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