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1.
J Anim Ecol ; 92(8): 1489-1508, 2023 08.
Article in English | MEDLINE | ID: mdl-36914973

ABSTRACT

Disgust is an adaptive system hypothesized to have evolved to reduce the risk of becoming sick. It is associated with behavioural, cognitive and physiological responses tuned to allow animals to avoid and/or get rid of parasites, pathogens and toxins. Little is known about the mechanisms and outcomes of disease avoidance in wild animals. Furthermore, given the escalation of negative human-wildlife interactions, the translation of such knowledge into the design of evolutionarily relevant conservation and wildlife management strategies is becoming urgent. Contemporary methods in animal ecology and related fields, using direct (sensory cues) or indirect (remote sensing technologies and machine learning) means, provide a flexible toolbox for testing and applying disgust at individual and collective levels. In this review/perspective paper, we provide an empirical framework for testing the adaptive function of disgust and its associated disease avoidance behaviours across species, from the least to the most social, in different habitats. We predict various trade-offs to be at play depending on the social system and ecology of the species. We propose five contexts in which disgust-related avoidance behaviours could be applied, including endangered species rehabilitation, invasive species, crop-raiding, urban pests and animal tourism. We highlight some of the perspectives and current challenges of testing disgust in the wild. In particular, we recommend future studies to consider together disease, predation and competition risks. We discuss the ethics associated with disgust experiments in the above contexts. Finally, we promote the creation of a database gathering disease avoidance evidence in animals and its applications.


Le dégoût est un système adaptatif supposé avoir évolué afin de réduire le risque de tomber malade. Il est associé à des réponses comportementales, cognitives et physiologiques adaptées pour permettre aux animaux d'éviter et/ou de se débarrasser des parasites, pathogènes et toxines. On sait peu de choses sur les mécanismes et les conséquences de l'évitement des maladies chez les animaux sauvages. Étant donné l'escalade des interactions négatives entre humains et faune, la traduction de ces connaissances dans la conception de stratégies de conservation et de gestion de la faune - prenant en considération l'évolution des espèces - devient urgente. Les méthodes contemporaines en écologie animale et dans les domaines connexes, utilisant des moyens directs (indices sensoriels) ou indirects (technologies de télédétection et apprentissage automatique), fournissent une boîte à outils flexible pour tester et appliquer le dégoût aux niveaux individuel et collectif. Dans cet article de revue/perspective, nous fournissons un cadre empirique pour tester la fonction adaptative du dégoût et les comportements associés d'évitement des maladies chez différentes espèces - des moins sociales aux plus sociales, et dans différents habitats. Nous prédisons divers compromis en fonction du système social et de l'écologie de l'espèce. Nous proposons cinq contextes dans lesquels les comportements d'évitement liés au dégoût pourraient être appliqués: la réhabilitation d'espèces menacées; les espèces envahissantes; les dommages aux cultures; les nuisibles urbains; et le tourisme animalier. Nous mettons en avant certaines perspectives et défis actuels de l'expérimentation sur le dégoût en milieu naturel. En particulier, nous recommandons la considération de plusieurs risques ensemble: maladie, prédation et compétition. Nous discutons également de l'éthique associée aux expériences sur le dégoût dans les contextes ci-dessus. Enfin, nous promouvons la création d'une base de données rassemblant les stratégies d'évitement des maladies chez les animaux et leurs applications.


Subject(s)
Disgust , Parasites , Animals , Humans , Animals, Wild , Cues , Avoidance Learning
2.
Curr Biol ; 32(11): 2556-2562.e2, 2022 06 06.
Article in English | MEDLINE | ID: mdl-35508171

ABSTRACT

To camouflage themselves on the seafloor, European cuttlefish Sepia officinalis control the expression of about 30 pattern components to produce a range of body patterns.1 If each component were under independent control, cuttlefish could produce at least 230 patterns. To examine how cuttlefish deploy this vast potential, we recorded cuttlefish on seven experimental backgrounds, each designed to resemble a pattern component, and then compared their responses to predictions of two models of sensory control of component expression. The body pattern model proposes that cuttlefish integrate low-level sensory cues to categorize the background and co-ordinate component expression to produce a small number of overall body patterns.2-4 The feature matching model proposes that each component is expressed in response to one (or more) local visual features, and the overall pattern depends upon the combination of features in the background. Consistent with the feature matching model, six of the backgrounds elicited a specific set of one to four components, whereas the seventh elicited eleven components typical of a disruptive body pattern. This evidence suggests that both modes of control are important, and we suggest how they can be implemented by a recent hierarchical model of the cuttlefish motor system.5,6.


Subject(s)
Decapodiformes , Sepia , Animals , Cues , Decapodiformes/physiology , Sepia/physiology , Visual Perception
3.
Sci Rep ; 12(1): 2514, 2022 02 15.
Article in English | MEDLINE | ID: mdl-35169192

ABSTRACT

Despite numerous studies demonstrating the cognitive ability of cephalopods, there is currently no study showing an emotion-like behavior in this group of animals. To examine whether cuttlefish have different internal states, we developed a behavioral paradigm to assess if prior surprised events are able to alter the choice made by cuttlefish. By presenting unexpected food rewards to cuttlefish before the test, we investigated whether the reaction time of choosing between two shrimps, an intuitive response toward the prey without previous learning, at three different levels of discriminative tests (easy, difficult, and ambiguous), are different compared to the one without an unexpected reward. This behavioral paradigm serves to demonstrate whether cuttlefish are aware of ambiguous situations, and their choice outcome and reaction time are dependent of their internal states. The results show that the response latency was significantly shortened in the difficult and ambiguous tests when choosing from two shrimps that are either moderately different in size or similar sizes, respectively, when cuttlefish have received unexpected rewards before the test. These results were compared with tests during which the cuttlefish did not receive any reward in advance. Furthermore, this shortening of latency did not result in a difference in choice outcome during the difficult and ambiguous tests. Interestingly, even when cuttlefish have obtained the expected food rewards or simply made tentacular strike without prey capture each time before test, these prior experiences were sufficient to shorten the response latency in the difficult and ambiguous tests. However, different from the result of unexpected rewards, food consumption alone or prey capture failure did affect the choice outcome during the simple and difficult tests. Taken together, our findings suggest that pre-test treatments of unexpected and expected rewards or simply unsuccessful visual attack seem to induce cuttlefish to adopt different foraging behaviors. This context dependent decision making suggests that cuttlefish's foraging strategies are influenced by the previously surprised event and their internal states. It also shows a speed-accuracy tradeoff in difficult and ambiguous situations when foraging for prey. This observation may lead to a future investigation of the presence of emotional state in cephalopods.


Subject(s)
Behavior, Animal/physiology , Choice Behavior/physiology , Decapodiformes/physiology , Predatory Behavior/physiology , Reward , Animals , Appetite/physiology , Cognition , Decapoda , Emotions/physiology , Female , Learning/physiology , Reaction Time
4.
J Exp Biol ; 225(6)2022 03 15.
Article in English | MEDLINE | ID: mdl-35213895

ABSTRACT

As the sensory systems of vertebrates develop prenatally, embryos perceive many environmental stimuli that can influence the ontogeny of their behaviour. Whether the nature and intensity of prenatal stimuli affect this ontogeny differently remains to be investigated. In this context, this study aimed to analyse the effects of prenatal auditory stimulation (natural stimulation, NS; predator vocalisations or artificial stimulation, AS; metallic sounds) on the subsequent behaviour of young Japanese quail (Coturnix coturnix japonica). For this, behavioural variables recorded during ethological tests evaluating emotional and social reactivity were analysed using a principal component analysis. This analysis revealed significant differences between the behavioural profile of stimulated chicks and that of non-exposed chicks. Indeed, chicks exposed to NS expressed more intense emotional responses in fearful situations, but less neophobia when exposed to a novel environment or object, whereas chicks exposed to AS appeared more sensitive to social isolation. Our results show that the acoustic environment of embryos can influence the way young birds subsequently interact with their social and physical environment after hatching, and face challenges in changing living conditions.


Subject(s)
Coturnix , Vitamins , Animals , Chickens , Ethology , Female , Social Isolation
5.
Psychoneuroendocrinology ; 137: 105661, 2022 03.
Article in English | MEDLINE | ID: mdl-35038662

ABSTRACT

Prenatal maternal stress (PMS) influences many facets of offspring's phenotype including morphology, behaviour and cognitive abilities. Recent research suggested that PMS also induced epigenetic modifications. In the present study, we analysed, in the Japanese quail, the effects of PMS on the emotional reactivity and cognitive abilities of the F1 offspring. We also investigated in the hippocampus, the paraventricular hypothalamic nucleus and subnuclei of the arcopallium/amygdala the level of two histone post-translational modifications, H3K4me2 and H3K27me3, known to be impacted by stress. We found that PMS does not affect F1 quail's learning abilities but increases their emotional reactivity. Moreover, we demonstrated that PMS induced an increased density of H3K27me3 positive cells, in the hippocampus, paraventricular hypothalamic nucleus and dorsal nucleus of the amygdala, but not variations of H3K4me2. As these brain regions are involved in the control of vertebrates' emotional responses, the effect of PMS on the epigenetic mark H3K27me3 could possibly be a mechanism involved in the behavioural effects we observed in F1 quail.


Subject(s)
Coturnix , Histones , Animals , Behavior, Animal , Coturnix/genetics , Epigenesis, Genetic , Female , Histones/genetics , Pregnancy , Quail
6.
Front Physiol ; 12: 622126, 2021.
Article in English | MEDLINE | ID: mdl-33643067

ABSTRACT

In La Manche (English Channel) the level of turbidity changes, not only seasonally and daily in seawater but also along the coast. As a consequence, vision in marine species is limited when based only on contrast-intensity. It is hypothesized that polarization sensitivity (PS) may help individuals detect preys and predators in turbid environments. In the cuttlefish, Sepia officinalis, to date, all behavioral studies have been conducted on animals reared in clear water. But the cuttlefish sensory system is adapted to a range of turbid environments. Our hypothesis was that rearing cuttlefish in clear water may affect the development of their visual system, and potentially affect their visually guided behaviors. To test this, newly-hatched cuttlefish, from eggs laid by females brought in from the wild, were reared for 1 month under three different conditions: clear water (C group), low turbidity (0.1 g / l of clay, 50-80 NTU, LT group) and high turbidity (0.5 g / l of clay, 300-400 NTU, HT group). The visual capacities of cuttlefish were tested with an optomotor apparatus at 7 days and at 1 month post-hatching. Optomotor responses of juveniles were measured by using three screen patterns (black and white stripes, linearly polarized stripes set at different orientations, and a uniform gray screen). Optomotor responses of juveniles suggest that exposure to turbid water improves the development of their PS when tested in clear water (especially in LT group) but not when tested in turbid water. We suggest that the use of slightly turbid water in rearing systems may improve the development of vision in young cuttlefish with no detrimental effect to their survival rate. Future research will consider water turbidity as a possible factor for the improvement of cuttlefish well-being in artificial rearing systems.

7.
Learn Behav ; 48(4): 401-410, 2020 12.
Article in English | MEDLINE | ID: mdl-32221844

ABSTRACT

Predation can be a very strong selective pressure on prey. Many studies have shown the existence of innate anti-predator responses, mostly in the early developmental stages of juvenile vertebrates. Learning to recognize predators is another possible defensive resource, but such a method involves a high death risk. There is evidence that prenatal learning exists in animals but few studies have explicitly tested for embryonic learning. The aim of this study was to test innate and learned predator recognition in cuttlefish embryos. For this, naïve embryos were exposed to chemical and visual cues emanating from predators, non-predators, and ink. Their response was assessed by measuring their ventilation rate (VR). We first show that VR decreased in response to both visual and chemical predatory cues and ink but not to non-predatory cues. Second, we show that when non-predatory cues (visual or chemical) are paired with predatory cues or ink for several days, embryonic VR significantly decreased. Such a response is likely adaptive, especially in a translucent egg, since it results in reduced movement and hence may lower the risk of detection by visual predators. This freezing-like behavior may also reduce the bioelectric field, thus lessening the predation risk by non-visual foragers. Our results report that cuttlefish embryos had an innate capacity to differentiate between harmless and harmful chemical and visual cues. They were also capable of learning to respond to harmless cues when they were paired with danger (predator or ink) based on conditioning. The combination of these behavioral mechanisms is an example of the early adaptability of cephalopods. Such behavioral plasticity may give the newly hatched cuttlefish a selective advantage when dealing with either known or unfamiliar threats. Nevertheless, more experiments are needed to test the efficiency of the embryos' response faced with known or new predators.


Subject(s)
Decapodiformes , Learning , Animals , Cues , Predatory Behavior , Recognition, Psychology
8.
Dev Psychobiol ; 61(7): 1014-1021, 2019 11.
Article in English | MEDLINE | ID: mdl-31172508

ABSTRACT

Embryos perceive environmental stimuli, thanks to their almost mature sensory systems. In cuttlefish, the embryonic development of Sepia officinalis and Sepia pharaonis is similar but the egg capsule transparency is different. S. officinalis' eggs are black (ink), which provide protection from predators. Conversely, those of S. pharaonis are translucent. The aim of this study was to test the visual and chemosensory perception abilities of these two cuttlefish embryos by observation of the ventilation rate (VR) before and after stimulation. Our results show that S. pharaonis responds to light at stage 22 and S. officinalis at stage 24. Conversely, S. pharaonis responds to predator odor at stage 23 and S. officinalis at stage 22. Both species are able to respond to these stimuli before hatching but do not have the same developmental schedule. Neither are the responses of the two cuttlefish exactly the same. In S. officinalis, VR increases after stimulations. In S. pharaonis, VR increases after light stimulation and decreases following the odor stimulation after stage 25. This result could reveal an ability to recognize stimuli at stage 25. The decrease could be identified as freezing-like behavior which would be more adaptive than an increase, since the embryos are visible.


Subject(s)
Behavior, Animal/physiology , Embryonic Development/physiology , Olfactory Perception/physiology , Respiratory Rate/physiology , Sepia/physiology , Visual Perception/physiology , Animals , Species Specificity
9.
Physiol Behav ; 201: 175-183, 2019 03 15.
Article in English | MEDLINE | ID: mdl-30659872

ABSTRACT

Regular visual presence of humans is known to reduce chickens' human-generated stress responses. Here we questioned whether, more than mere visual presence, human behaviour affects laying hen behaviour and subsequently their offspring's behaviour. We hypothesized that human behaviour triggers maternal effects via variations in yolk hormone levels. For five consecutive weeks, two groups of hens were exposed to the same durations of human presence (30 min twice a day, five days a week) but the behaviour of the human differed between groups. The first group (H+) was exposed to predictable arrival of the experimenter, slow movements combined with static presence, stroking during handling and human voice. Whereas the second group of hens (H-) was exposed to unpredictable arrival of the experimenter which remained silent, in motion, and did not provide stroking during handling. At the end of the treatment, we evaluated egg quality and offspring behaviour. We found that avoidance of the experimenter by H+ hens but not by H- hens decreased significantly. Fertility rates and concentrations of yolk progesterone and estradiol in H+ hens' eggs were higher than in H- hens' eggs. Fear of humans, neophobia or the capacity to solve a detour task did not differ significantly between H+ and H- chicks. Social discrimination tests showed that H+ chicks but not H- chicks typically preferred a familiar conspecific to a stranger. These results show that, with the same duration in the presence of the birds, humans through their behaviour engender variations in fertility rates, yolk hormone levels and transgenerational effects on social skills. Rarely explored, our data suggest that maternal effects influence filial imprinting. These data have broad implications for laboratory, commercial systems and conservatory programs where the inevitable presence of humans could trigger maternal effects on offspring phenotype.


Subject(s)
Behavior, Animal/physiology , Chickens , Animals , Animals, Newborn , Egg Yolk/chemistry , Estradiol/analysis , Fear/physiology , Female , Fertility , Humans , Imprinting, Psychological , Male , Progesterone/analysis , Social Behavior
10.
Sci Rep ; 8(1): 1857, 2018 01 30.
Article in English | MEDLINE | ID: mdl-29382895

ABSTRACT

The influence of embryonic microclimate on the behavioural development of birds remains unexplored. In this study, we experimentally tested whether chronic exposure to suboptimal temperatures engendered plasticity in the expression of fear-related behaviours and in the expression of the corticotropin-releasing factor in the brains of domestic chicks (Gallus g. domesticus). We compared the neurobehavioural phenotypes of a control group of chicks incubated in an optimal thermal environment (37.8 °C) with those of a group of experimental chicks exposed chronically in ovo to suboptimal temperatures (27.2 °C for 1 hour twice a day). Chronic exposure to a suboptimal temperature delayed hatching and decreased growth rate and experimental chicks had higher neophobic responses than controls in novel food and novel environment tests. In addition, experimental chicks showed higher expression of corticotropin-releasing factor than did controls in nuclei of the amygdala, a structure involved in the regulation of fear-related behaviours. In this study, we report the first evidence of the strong but underappreciated role of incubation microclimate on the development of birds' behaviour and its neurobiological correlates.


Subject(s)
Behavior, Animal , Body Temperature Regulation , Chickens/physiology , Fear/physiology , Neurosecretory Systems/physiology , Temperature , Animals , Corticotropin-Releasing Hormone/metabolism
11.
Front Physiol ; 8: 981, 2017.
Article in English | MEDLINE | ID: mdl-29249984

ABSTRACT

Stress experienced during prenatal development-either applied to reproducing females (maternal stress), directly to developing offspring (embryonic stress) or in combination-is associated with a range of post-natal behavioral effects in numerous organisms. We conducted an experiment to discern if maternal and embryonic stressors affect the behavior of hatchlings of the cuttlefish Sepia officinalis, a species with features that allow for the examination of these stress types in isolation. Separating the impact of stress transmitted through the mother vs. stress experienced by the embryo itself will help clarify the behavioral findings in viviparous species for which it is impossible to disentangle these effects. We also compared the effect of a naturally-occurring (predator cue) and an "artificial" (bright, randomly-occurring LED light) embryonic stressor. This allowed us to test the hypothesis that a threat commonly faced by a species (natural threat) would be met with a genetically-programmed and adaptive response while a novel one would confound innate defense mechanisms and lead to maladaptive effects. We found that the maternal stressor was associated with significant differences in body patterning and activity patterns. By contrast, embryonic exposure to stressors increased the proportion of individuals that pursued prey. From these results, it appears that in cuttlefish, maternal and embryonic stressors affect different post-natal behavior in offspring. In addition, the effect of the artificial stressor suggests that organisms can sometimes react adaptively to a stressor even if it is not one that has been encountered during the evolutionary history of the species.

12.
Curr Biol ; 27(20): R1093-R1095, 2017 Oct 23.
Article in English | MEDLINE | ID: mdl-29065284

ABSTRACT

In this quick guide, Darmaillacq and Osorio introduce the reader to the fascinating biology of the cuttlefish.


Subject(s)
Behavior, Animal , Decapodiformes/physiology , Life History Traits , Perception , Animals
13.
Front Physiol ; 8: 402, 2017.
Article in English | MEDLINE | ID: mdl-28659822

ABSTRACT

Cuttlefish are highly visual animals, a fact reflected in the large size of their eyes and visual-processing centers of their brain. Adults detect their prey visually, navigate using visual cues such as landmarks or the e-vector of polarized light and display intense visual patterns during mating and agonistic encounters. Although much is known about the visual system in adult cuttlefish, few studies have investigated its development and that of visually-guided behavior in juveniles. This review summarizes the results of studies of visual development in embryos and young juveniles. The visual system is the last to develop, as in vertebrates, and is functional before hatching. Indeed, embryonic exposure to prey, shelters or complex background alters postembryonic behavior. Visual acuity and lateralization, and polarization sensitivity improve throughout the first months after hatching. The production of body patterning in juveniles is not the simple stimulus-response process commonly presented in the literature. Rather, it likely requires the complex integration of visual information, and is subject to inter-individual differences. Though the focus of this review is vision in cuttlefish, it is important to note that other senses, particularly sensitivity to vibration and to waterborne chemical signals, also play a role in behavior. Considering the multimodal sensory dimensions of natural stimuli and their integration and processing by individuals offer new exciting avenues of future inquiry.

14.
Front Physiol ; 8: 173, 2017.
Article in English | MEDLINE | ID: mdl-28396639

ABSTRACT

While octopuses are mostly benthic animals, and squid prefer the open waters, cuttlefish present a special intermediate stage. Although their body structure resembles that of a squid, in many cases their behavior is mostly benthic. To test cuttlefish's preference in the use of space, we trained juvenile Sepia gibba and Sepia officinalis cuttlefish to reach a shelter at the opposite side of a tank. Afterwards, rock barriers were placed between the starting point and the shelter. In one experiment, direct paths were available both through the sand and over the rocks. In a second experiment the direct path was blocked by small rocks requiring a short detour to by-pass. In the third experiment instead, the only direct path available was over the rocks; or else to reach the goal via an exclusively horizontal path a longer detour would have to be selected. We showed that cuttlefish prefer to move horizontally when a direct route or a short detour path is available close to the ground; however when faced with significant obstacles they can and would preferentially choose a more direct path requiring a vertical movement over a longer exclusively horizontal path. Therefore, cuttlefish appear to be predominantly benthic dwellers that prefer to stay near the bottom. Nonetheless, they do view and utilize the vertical space in their daily movements where it plays a role in night foraging, obstacles negotiation and movement in their home-range.

15.
Dev Psychobiol ; 59(3): 400-409, 2017 04.
Article in English | MEDLINE | ID: mdl-28261786

ABSTRACT

We assessed whether the ratio of dietary n-6/n-3 polyunsaturated fatty acids (PUFA) during egg formation engenders transgenerational maternal effects in domestic chicks. We analyzed yolk lipid and hormone concentrations, and HPA-axis activity in hens fed a control diet (high n-6/n-3 ratio) or a diet enriched in n-3 PUFAs (low n-6/n-3 ratio) for 6 consecutive weeks. Their chicks were tested for neophobia during the first week of life. We found higher corticosterone metabolites in droppings of hens fed the diet enriched in n-3 and significantly higher concentrations of yolk progesterone, androstenedione, and estradiol in their eggs compared to controls. Chicks of hens fed the n-3 enriched diet showed a lower body mass at hatch than controls and expressed higher neophobia when exposed to a novel object. These results add support to the hypothesis that the nutritional state of female birds produces variation in yolk hormone levels and engender maternal effects.


Subject(s)
Androstenedione/metabolism , Animal Nutritional Physiological Phenomena/physiology , Behavior, Animal/physiology , Egg Yolk/metabolism , Estradiol/metabolism , Fatty Acids, Omega-3 , Fatty Acids, Omega-6 , Progesterone/metabolism , Animals , Chickens , Female
16.
Dev Psychobiol ; 59(2): 145-160, 2017 03.
Article in English | MEDLINE | ID: mdl-27714785

ABSTRACT

Though a mollusc, the cuttlefish Sepia officinalis possesses a sophisticated brain, advanced sensory systems, and a large behavioral repertoire. Cuttlefish provide a unique perspective on animal behavior due to their phylogenic distance from more traditional (vertebrate) models. S. officinalis is well-suited to addressing questions of behavioral ontogeny. As embryos, they can perceive and learn from their environment and experience no direct parental care. A marked progression in learning and behavior is observed during late embryonic and early juvenile development. This improvement is concomitant with expansion and maturation of the vertical lobe, the cephalopod analog of the mammalian hippocampus. This review synthesizes existing knowledge regarding embryonic and juvenile development in this species in an effort to better understand cuttlefish behavior and animal behavior in general. It will serve as a guide to future researchers and encourage greater awareness of the utility of this species to behavioral science.


Subject(s)
Behavior, Animal/physiology , Embryo, Nonmammalian/physiology , Learning/physiology , Sepia/physiology , Animals , Sepia/growth & development
17.
Invert Neurosci ; 13(1): 19-26, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23549755

ABSTRACT

Cuttlefish possess the complex ability to identify approaching threats and then to selectively express the appropriate defense. We examined the visual cues used by Sepia officinalis cuttlefish during predator detection and the responses they selected. Using computer-generated stimuli, we set out to quantitate the deimatic responses to artificial looming stimuli of different shapes and contrasts. Defensive behavior gradually intensified as geometrical shapes resembled an image of a fish. Therefore, in addition to an object's size or its sudden increase in size, cuttlefish use form recognition to identify a threat. Cuttlefish demonstrated equal performance in predator detection trough clear water when presented with intensity versus polarization contrasts. However, when the water turbidity increased, the cuttlefish still detected looming fish shapes based on polarization contrast even when intensity information alone did not suffice. These results demonstrate the interplay between intensity and polarization information transmission and processing in the spatial domain. As nectobenthic organisms, cuttlefish probably experience low visibility conditions on a regular basis. The ability to see further into turbid water and to better detect an approaching object would be beneficial for their survival.


Subject(s)
Behavior, Animal/physiology , Sepia/physiology , Vision, Ocular/physiology , Animals , Cues , Europe
18.
Aquat Toxicol ; 132-133: 84-91, 2013 May 15.
Article in English | MEDLINE | ID: mdl-23474317

ABSTRACT

Recent ecotoxicological studies highlight the increasing presence of pharmaceuticals discharged in the aquatic environment. Amongst them is the antidepressant fluoxetine (FLX), a selective serotonin reuptake inhibitor, primarily indicated for treatment of depression. The effect of chronic exposure to FLX on memory processing in 1-month-old cuttlefish Sepia officinalis was evaluated. Three groups of new-borns were reared in different conditions: one control group (no FLX) and two groups exposed to environmental concentrations of FLX (1 and 100ng/L) from 15 days pre-hatching to 1 month post-hatching. Acquisition and retention performances were assessed using the 'prawn-in-the-tube' procedure. Perinatal exposure to fluoxetine led to significant changes in memory processing of the animals. The lowest observed effect concentration of this antidepressant on learning and retention was 1ng/L which is under the range of environmental contamination. Cuttlefish exposed at low FLX concentration had impaired acquisition capabilities and animals exposed at high FLX concentration displayed a deficit of memory retention compared to the control group that had nonimpaired initial acquisition and retention performances. The results subsequently suggested that FLX-induced changes in cognitive capacities could potentially lead to inappropriate predatory behaviors in the natural environment. The study provides the basis for future studies on how pharmaceutical contaminants disrupt cognition in ecologically and economically relevant marine invertebrates.


Subject(s)
Fluoxetine/toxicity , Selective Serotonin Reuptake Inhibitors/toxicity , Sepia/drug effects , Water Pollutants, Chemical/toxicity , Animals , Avoidance Learning/drug effects , Memory/drug effects , Sepia/physiology
19.
J Exp Biol ; 216(Pt 11): 2039-45, 2013 Jun 01.
Article in English | MEDLINE | ID: mdl-23430993

ABSTRACT

Polarization sensitivity is a characteristic of the visual system of cephalopods. It has been well documented in adult cuttlefish, which use polarization sensitivity in a large range of tasks such as communication, orientation and predation. Because cuttlefish do not benefit from parental care, their visual system (including the ability to detect motion) must be efficient from hatching to enable them to detect prey or predators. We studied the maturation and functionality of polarization sensitivity in newly hatched cuttlefish. In a first experiment, we examined the response of juvenile cuttlefish from hatching to the age of 1 month towards a moving, vertically oriented grating (contrasting and polarized stripes) using an optomotor response apparatus. Cuttlefish showed differences in maturation of polarization versus luminance contrast motion detection. In a second experiment, we examined the involvement of polarization information in prey preference and detection in cuttlefish of the same age. Cuttlefish preferentially chose not to attack transparent prey whose polarization contrast had been removed with a depolarizing filter. Performances of prey detection based on luminance contrast improved with age. Polarization contrast can help cuttlefish detect transparent prey. Our results suggest that polarization is not a simple modulation of luminance information, but rather that it is processed as a distinct channel of visual information. Both luminance and polarization sensitivity are functional, though not fully matured, in newly hatched cuttlefish and seem to help in prey detection.


Subject(s)
Sepia/physiology , Animals , Contrast Sensitivity , Light , Luminescence , Predatory Behavior , Sepia/growth & development , Vision, Ocular
20.
Behav Brain Res ; 240: 29-32, 2013 Mar 01.
Article in English | MEDLINE | ID: mdl-23178535

ABSTRACT

For several decades the "prawn-in-the-tube" procedure has been extensively used in the exploration of behavioral plasticity and its neural correlates in cuttlefish. Although the nature of the task has been characterized, the effect of reinforcement and the extent of different cues cuttlefish can use to solve and memorize the task remain unclear. To determine whether cuttlefish learned to inhibit predatory behavior because of pain incurred when the tentacles hit the glass tube, the shrimp prey (typically attacked with a tentacle strike) was replaced by crabs (normally caught by a jumping strategy, using all eight arms together, which is thought less likely to be painful). We showed that the cuttlefish is still capable of learning inhibition of predatory behavior when it adopts another catching strategy, which suggests that pain from the tentacles hitting the tube has little effect on the learning process. The two latest experiments have shown that cuttlefish do not learn to inhibit predatory behavior towards a specific type of prey, but rather learn and memorize visual (light polarization) and tactile information from the glass tube. The "prawn-in-the-tube" procedure is a powerful and user-friendly tool in the investigation of the processing and retention of multisensory information in invertebrates. Our recent findings now open up new areas of investigation into the neural correlates of learning and memory processes in cuttlefish.


Subject(s)
Association Learning/physiology , Inhibition, Psychological , Memory/physiology , Predatory Behavior/physiology , Reinforcement, Psychology , Sepia/physiology , Animals , Cues , Pattern Recognition, Visual/physiology , Species Specificity
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