A team of researchers at the University of Exeter, UK, studied how Trinidadian guppies (Poecilia reticulata) behaved in various situations and found complex differences between individuals. The results are published in the journal Functional Ecology.

Coping with challenging environments and situations is a necessary part of life. Previous research have shown that individuals within a population may vary in the way they respond to stress, and this variation is considered to exist on a simple spectrum of ‘risk-averse’ to ‘risk-prone’ styles of coping.

Dr. Tom Houslay, lead author on the study and a researcher in the Centre for Ecology and Conservation (CEC) at the University of Exeter, and co-authors wanted to test this idea of a single underlying axis of coping styles, using a suite of behaviors related to risk-taking. The researchers also wanted to test individual consistency across different stress contexts.

“We tested whether differences could be measured on a simple spectrum of how risk-averse or risk-prone guppies were. But we found variations between individuals were too complicated to be described in this way,” they said.

“The idea of a simple spectrum is often put forward to explain the behavior of individuals in species such as the Trinidadian guppy,” Dr. Houslay explained.

“But our research shows that the reality is much more complex. For example, when placed into an unfamiliar environment, we found guppies have various strategies for coping with this stressful situation — many attempt to hide, others try to escape, some explore cautiously, and so on.”

“The differences between them were consistent over time and in different situations,” he said.

“So, while the behavior of all the guppies changed depending on the situation — for example, all becoming more cautious in more stressful situations — the relative differences between individuals remained intact.”

The team examined the ‘coping styles’ of Trinidadian guppies in conditions designed to cause varying levels of stress.

Mild stress was caused by transferring fish individually to an unfamiliar tank, and higher levels of stress were caused by adding models of predatory birds or fish.

The presence of predators had an effect on ‘average’ behavior — making all of the guppies more cautious overall — but individuals still retained their distinct personalities.

“We are interested in why these various personalities exist, and the next phase of our research will look at the genetics underlying personality and associated traits,” said senior author Professor Alastair Wilson, also from the CEC at the University of Exeter.

“We want to know how personality relates to other facets of life, and to what extent this is driven by genetic — rather than environmental — influences.”

“The goal is really gaining insight into evolutionary processes, how different behavioral strategies might persist as species evolve.”

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Thomas M. Houslay et al. Testing the stability of behavioural coping style across stress contexts in the Trinidadian guppy. Functional Ecology, published online September 24, 2017; doi: 10.1111/1365-2435.12981