When the chips are down, having a strong personality may be the difference between thriving and failing, according to new research which studied how aphids reacted when faced with predatory ladybirds.
The study, conducted by the University of Exeter and the University of Osnabrueck, is published in the Journal of Animal Ecology and suggests that committing to a consistent behavioural type in times of crisis results in the best overall outcome in terms of fitness and reproductive success.
The researchers conducted experiments with red and green pea aphids in tanks, where they monitored differences in escape response upon a ladybird attack. When faced with a predator, the aphids either employ a risk-averse strategy of dropping from the plant and running away, or a risk-prone strategy of hunkering down and staying put.
These simulated attacks - in which the ladybirds were ultimately prevented from eating the aphids - were repeated to see if the aphids changed their behaviour or were committed to a chosen lifestyle. They found that those aphids which displayed consistent behaviour (either always dropping or never dropping) did better than those which did a bit of both.
Author Sasha Dall from the Centre for Ecology & Conservation at the University of Exeter said: "When faced with a predator, some aphids are consistently brave, some are not and some don't display any personality. We found that when the consequences are dire it is important for the aphid to commit to a lifestyle, whether it is to run away or to stay put. When life is easier, however, it matters less whether the aphids have strong personalities or not."
The researchers found that because red aphids are more conspicuous than green, life is harsher and so the consequences of dropping vs not dropping are more extreme.
Lead author Wiebke Schuett, now at the University of Hamburg, explained: "For red aphids it was particularly important to either commit to a 'live fast die young' lifestyle ignoring the increased threat from predators, or to always run away when threatened in order to forage more and live longer. Both decisions resulted in strong pay offs, but only if the aphids remained consistent."
"Life-history trade-offs mediate 'personality' variation in two colour morphs of the pea aphid, Acyrthosiphon pisum" by Wiebke Schuett, Sasha Dall, Michaela Kloesener, Jana Baeumer, Felix Beinlich and Till Eggers is published in the Journal of Animal Ecology.
This work was funded by a Research Grant to Wiebke Schuett, Sasha Dall and Till Eggers from The Association for the Study of Animal Behaviour (UK).
For more information contact:
University of Exeter Press Office
+44 (0)1392 722405 or 722062
About the University of Exeter
The University of Exeter is a Russell Group university and in the top one percent of institutions globally. It combines world-class research with very high levels of student satisfaction. Exeter has over 19,000 students and is ranked 7th in The Times and The Sunday Times Good University Guide league table, 10th in The Complete University Guide and 12th in the Guardian University Guide 2014. In the 2014 Research Excellence Framework (REF), the University ranked 16th nationally, with 98% of its research rated as being of international quality. Exeter was The Sunday Times University of the Year 2012-13.
The University has four campuses. The Streatham and St Luke's campuses are in Exeter and there are two campuses in Cornwall, Penryn and Truro. The 2014-2015 academic year marks the 10-year anniversary of the two Cornwall campuses. In a pioneering arrangement in the UK, the Penryn Campus is owned and jointly managed with Falmouth University. At the campus, University of Exeter students can study programmes in the following areas: Animal Behaviour, Conservation Biology and Ecology, English, Environmental Science, Evolutionary Biology, Geography, Geology, History, Human Sciences, Mining and Minerals Engineering, Politics and International Relations, Renewable Energy and Zoology.
The University has invested strategically to deliver more than £350 million worth of new facilities across its campuses in the past few years; including landmark new student services centres - the Forum in Exeter and The Exchange at Penryn - together with world-class new facilities for Biosciences, the Business School and the Environment and Sustainability Institute. There are plans for another £330 million of investment between now and 2016.
Journal of Animal Ecology