SUMMARYIt is now well established that prenatal sensory experience affects development itself and has long-term consequences in terms of postnatal behavior. This study focused on the functionality of the sensory system in cuttlefish in ovo. Embryos of stage 23, 25 and 30 received a tactile, chemical or visual stimulus. An increase of mantle contraction rhythm was taken to indicate a behavioral response to the stimulus. We clearly demonstrated that tactile and chemical systems are functional from stage 23, whereas the visual system is functional only from stage 25. At stage 25 and 30, embryos were also exposed to a repeated light stimulus. Stage 30 embryos were capable of habituation, showing a progressive decrease in contractions across stimulations. This process was not due to fatigue as we observed response recovery after a dishabituation tactile stimulus. This study is the first to show that cuttlefish embryos behaviorally respond to stimuli of different modalities and that the visual system is the last to become functional during embryonic development, as in vertebrate embryos. It also provides new evidence that the memory system develops in ovo in cuttlefish.

No abstract

No abstract

Cephalopods are generally regarded as the most intelligent group among the invertebrates. Despite their popularity, relatively little is known about the range and function of their cognitive abilities. This book fills that gap, accentuating the varied and fascinating aspects of cognition across the group. Starting with the brain, learning and memory, Part I looks at early learning, memory acquisition and cognitive development in modern cephalopods. An analysis of the chambered nautilus, a living fossil, is included, providing insight into the evolution of behavioural complexity. Part II surveys environmental responses, especially within the active and learning-dependent coleoids. The ever-intriguing camouflage abilities of octopus and cuttlefish are highlighted, alongside bioluminescence, navigation and other aspects of visual and cognitive competence. Covering the range of cognitive function, this text underscores the importance of the cephalopods within the field of comparative cognition generally. It will be highly valuable for researchers, graduates and senior undergraduate students.

Food preferences were investigated in cuttlefish during the first 3 months' posthatching, using choice tests between crabs, shrimps, and young fish. The results showed that without previous feeding experience, cuttlefish preferred shrimps on Day 3. This suggests an innate food preference; however, it was possible to induce a preference for an originally nonpreferred prey item in 3-day-old and naïve cuttlefish, demonstrating the flexibility of this initial behavioral preference in response to previous individual experience. This preference suggests a learning process involving a form of long-term memory, demonstrated for the first time in juvenile cuttlefish. Until Day 30, juvenile cuttlefish fed exclusively shrimps chose shrimps. This preference probably depends on their previous feeding experience. Finally, it appears that from Day 60, cuttlefish reared on the same restricted diet have a tendency to switch their preference to novel prey items, which diversify their diet.