Olfactory detection of dimethyl sulphide in a krill-eating Antarctic penguin

Abstract

In response to zooplankton grazing, phytoplankton release dimethylsulphoniopropionate in the seawater, which is then catabolized to dimethyl sulphide (DMS) that is emitted to the air. This molecule therefore signals areas of high productivity in the oceans, and it can be used by predators for locating foraging areas. Detection of this compound has been described in several species of procelariiform seabirds and non-Antarctic fish-feeding penguins. However, there is no evidence of DMS detection by krill-feeding penguins. The mechanisms of krill detection by its predators are especially relevant in Antarctica, where trophic webs are mainly based on krill. We explored for the first time whether a krill-feeding penguin species, the chinstrap penguin Pygoscelis antarctica, is able to detect DMS. We examined whether chinstrap penguins could detect DMS by locating DMS or control recipients in pathways that penguins used when moving between the colony and the sea. We also analysed the attraction of nestling penguins to DMS in a T-shaped experimental enclosure. Our results showed that adult penguins are attracted to DMS on land. Nestling penguins also tended to be attracted to the scent of DMS. Further research is needed to examine whether chinstrap penguins use natural DMS concentrations as a foraging cue at sea.