The behavioural effects of predator-induced stress responses in the cricket (Gryllus texensis): the upside of the stress response

Abstract

SUMMARYPredator-induced stress responses are thought to reduce an animal's risk of being eaten. Therefore, these stress responses should enhance anti-predator behaviour. We found that individual insects (the cricket Gryllus texensis) show reliable behavioural responses (i.e. behavioural types) in a plus-shaped maze. An individual's behaviour in the plus maze remained consistent for at least 1/2 of its adult life. However, after exposure to a model predator, both male and female crickets showed a reduced period of immobility and an increased amount of time spent under shelter compared with controls. These changes could be mimicked by injections of the insect stress neurohormone octopamine. These behavioural changes probably aid crickets in evading predators. Exposure to a model predator increased the ability of crickets to escape a live predator (a bearded dragon, Pogona vitticeps). An injection of octopamine had the same effect, showing that stress hormones can reduce predation. Using crickets to study the fitness consequences of predator-induced stress responses will help integrate ecological and biomedical concepts of 'stress'.

Non‐consumptive effects of a top‐predator decrease the strength of the trophic cascade in a four‐level terrestrial food web

“…This effect was likely mediated by the observed consumptive effects of mesopredators on herbivores and of herbivores on plants. Additionally, non‐consumptive effects of mesopredators presence on herbivore behaviour (Adamo et al ) could also have impacted this trophic cascade.…”

“…On the contrary, in the preliminary experiment, 100 crickets were added weekly keeping cricket density higher and allowing non‐consumptive effects of top‐predators on lizard's prey consumption to be maintained. Alternatively, crickets might have responded to lizard foraging behaviour changes in presence of top‐predator cues by changing their behaviour and food consumption (Adamo et al ), with subsequent consequences on primary production. Primary production was however negatively correlated to the number of crickets remaining at the end of the experiment, making the consumption of crickets the most likely explanation for the differences in primary production between treatments with and without top‐predator cues.…”

Drosophila increase exploration after visually detecting predators

“…For example, in the presence of bearded dragons ( Pogona vitticpes ) naïve adult crickets ( Gryllus texenis ) immediately seek shelter in the covered arms of a plus maze, whereas in the presence of a mock predator the crickets initially freeze before escaping suggesting innate differential responses to perceived predatory threats [10]. Different species of rodents will characteristically freeze or flee depending on the proximity and behavior of the predator, frequently swapping between the two defensive reactions in response to the predator’s behavior [11–13].…”

Predator stress-induced immunosuppression: trade-off, immune redistribution or immune reconfiguration?

“…Similarly, in insects, exposure to predators activates a stress response (Adamo and Baker, 2011), which increases survival from predator attack (Adamo et al, 2013) but can reduce disease resistance (Adamo and Parsons, 2006). Chronic exposure to predators is a common problem for many species (Boonstra, 2013).…”