Maternal and embryonic stress affect defensive and predatory behaviour in juvenile cuttlefish (#142)
Early experiences such as prenatal stress significantly influence the development of the brain and the organization of behavior. There has been an increased interest in the effects of elevated maternal stress levels during pregnancy on the behavior and physiology of offspring. In oviparous species, embryos also can experience stress but this is less investigated. Here, we are interested in quantifying the effects of prenatal stress (both maternal and embryonic stress) on the development of behavior in cuttlefish. They are oviparous and autonomous at birth, and hence are ideal models for examining this phenomenon since the effects of stress will not be confounded with those of parental influence. We exposed cuttlefish eggs to a range of prenatal predatory stimuli (odor cue, visual cue or both) or an artificial stimulus (strong light). female cuttlefish were also exposed stress (handling) before spawning. We then evaluated the defensive behavior of cuttlefish at hatching and their predatory behavior during their first encounter with prey four days after hatching. Cuttlefish exposed to both visual and odor cues from predators were more likely to pursue their prey, rather than to lie in wait and ambush it. This result implies that juveniles exposed to predators have more developed short term memory. Full predator exposure also appears to increase the distance at which a cuttlefish can detect prey, but decreases their accuracy in prey capture. It was found that the maternal stress group was significantly poorer than all other stress groups at producing both a uniform and disrupted camouflage pattern. 98% of the maternal stress group also made no attempted to capture prey. Both the maternal and artificial stress groups had a significantly smaller mantle length than the other stress groups, with maternal stress being the smallest on average. As a consequence, it appears that depending on its nature, stress has differential effects on juveniles.