Kidnapping' in the Antarctic animal world?

A puzzling relationship between amphipods and pteropods

Date:  September 10, 2018

Source:  Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research

Pteropods or sea snails, also called sea angels, produce chemical deterrents to ward off predators, and some species of amphipods take advantage of this by carrying pteropods piggyback to gain protection from their voracious predators. There is no recognisable benefit for the pteropod. On the contrary they starve: captured between the amphipod's legs they are unable to feed. Biologists working with Dr Charlotte Havermans at the Alfred Wegener Institute have investigated this phenomenon as part of a cooperation project with the University of Bremen. In an article in the journal Marine Biodiversity, they talk about kidnapping and explain the potential advantages of this association for both the host and its passenger.

Amphipods of the suborder Hyperiidea are popular prey for fish and sea birds. They play an important role in the Southern Ocean food web, which is why biologist Dr Charlotte Havermans is investigating the distribution, abundance and ecological role of various species of amphipods. To do so, she is taking samples on board the Research Vessel Polarstern from the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI). She works at the University of Bremen's working group Marine Zoology. The project is funded by the DFG (German Research Foundation) in the Priority Programme on Antarctic Research.

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Parasitic infection helps sea snails survive acidified seawater

May 18, 2016 by Colin Macleod

Flatworm-infected sea snails survive better in more acidified seawater than non-infected ones, surprising new University of Otago research has found.

The findings emerge from a 90-day experiment that examined death rates of the New Zealand mud snail in seawater at current pH levels and in conditions predicted for the years 2100 and 2300.

While the Department of Zoology researchers found that survival rates of infected snails showed little change between each condition, uninfected snails died at higher rates in the acidified seawater.

Study main author Dr Colin MacLeod says the likely explanation is that compared to uninfected sea snails, infected ones have more energy available to deal with the increased metabolic costs incurred in acidified seawater.

"Snails infected by flatworms are invariably 'castrated' by these parasites, meaning that they no longer expend energy on reproductive activities. This leaves them with more energy to maintain their acid-base balance and shell integrity in the acidified conditions," Dr MacLeod says.

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Predatory sea snails produce weaponized insulin

Date:

January 19, 2015

Source:

University of Utah

Summary:

Some cone snails add insulin to the venom cocktail they use to catch fish, biologists have discovered. Adding the hormone to the mix of venom toxins may have enabled predatory cone snails to disable entire schools of swimming fish with hypoglycemic shock. The snail insulin could prove useful as a tool to probe the systems the human body uses to control blood sugar and energy metabolism.

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Jumping Snails Left Grounded in Future Oceans

Jan. 7, 2014 — Sea snails that leap to escape their predators may soon lose their extraordinary jumping ability because of rising human carbon dioxide emissions, a team of international scientists has discovered.

Lead author of the study published today, Dr Sue-Ann Watson from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) and James Cook University observed that the conch snail, which uses a strong foot to leap away from approaching predators, either stops jumping, or takes longer to jump, when exposed to the levels of carbon dioxide projected for the end of this century.

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