Anemones have personalities too!

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Scientists from Devon have discovered that UK native sea anemones have different 'personalities'.

A team of researchers from Plymouth University studied the territorial disputes of Beadlet anemones (Actinia equina) resident on the coast of Devon and Cornwall.

The first stage of the research involved 'threatening' 65 different anemones by squirting them with a jet of sea water from a syringe. This action causes the anemone to rapidly retract its tentacles in defence. The scientists then recorded how long it took the anemone to decide the coast was clear, and that it was safe to open up again.

Each of the chosen anemones was tested three times over a two week period, but response times for individuals were very similar even when changes in water temperature was factored in. Typically each anemone stayed closed for around nine minutes, but a few were bolder and opened more rapidly.

Anemones regularly fight in the wild as they compete for the best territory and this 'resource-holding potential' (RHP) was investigated in a separate study where 82 fights were staged between pairs of anemones to see which factors led to success in battle.

Fighting often involves the use of their stinging cells called nematocytes, which leave strips of stinging skin on their opponent, but size alone is sometimes enough to convince would-be opponents to move along.

The researchers found that in contests where neither anemone stung, the biggest generally won, however if one stung but the other didn't overall size didn't matter and it was the size of the nematocytes that predicted the outcome.

If both anemones decided to stand and fight the winning factor was the number of successful stinging blows landed. Losers became more timid in subsequent fights.

A final study investigated how well the 'bold' anemones faired in disputes, and found that they won the most, often regardless of size, pointing to a potential advantage in being bold whereby they could inflict more attacks than their timid opponent, increasing their RHP.

The team hope that by understanding the links between aggression and boldness they can gain insight into the evolution of animal personality as well as how winning or losing effects an animal's RHP after fights.

Check out the video showing one of the bolder anemones.

 

For more information see the papers:

Briffa M, Greenaway J (2011) High In Situ Repeatability of Behaviour Indicates Animal Personality in the Beadlet Anemone Actinia equina (Cnidaria). PLoS ONE 6(7): e21963.doi:10.1371/journal.pone.0021963.

Rudin F S, Briffa M, The logical polyp: assessments and decisions during contests in the beadlet anemone Actinia equina. Behavioral Ecology (November-December 2011) 22 (6): 1278-1285. doi: 10.1093/beheco/arr125.

Rudin F S, Briffa M, Is boldness a resource-holding potential trait? Fighting prowess and changes in startle response in the sea anemone, Actinia equina. PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES.(Dec 2011) doi:10.1098/rspb.2011.2418.

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