Personality traits in dumpling squid (Euprymna tasmanica): context-specific traits and their correlation with biological characteristics

Feeling our place in the world: an active inference account of self-esteem

Self-esteem, the evaluation of one's own worth or value, is a critical aspect of psychological well-being and mental health. In this paper, we propose an active inference account of self-esteem, casting it as a sociometer or an inferential capacity to interpret one's standing within a social group. This approach allows us to explore the interaction between an individual's self-perception and the expectations of their social environment.When there is a mismatch between these perceptions and expectations, the individual needs to adjust their actions or update their self-perception to better align with their current experiences. We also consider this hypothesis in relation with recent research on affective inference, suggesting that self-esteem enables the individual to track and respond to this discrepancy through affective states such as anxiety or positive affect. By acting as an inferential sociometer, self-esteem allows individuals to navigate and adapt to their social environment, ultimately impacting their psychological well-being and mental health.

Under the influence of light: How light pollution disrupts personality and metabolism in hermit crabs

Anthropogenic disturbances are known to cause significant physiological and behavioural changes in animals and, thus, are the critical focus of numerous studies. Light pollution is an increasingly recognised source of disturbance that has the potential to impact animal physiology and behaviour. Here, we investigate the effect of constant light on a personality trait and metabolic rate in the European hermit crab Pagurus bernhardus. We used Bayesian mixed models to estimate average behavioural change (i.e. sample mean level behavioural plasticity) and between- and within-individual variation in boldness in response to laboratory light. Hermit crabs experiencing constant light were consistently less bold and had a higher metabolic rate than those kept under a standard laboratory light regime (12:12 h light/dark). However, there was no effect of light on individual consistency in behaviour. As boldness is associated with coping with risk, hermit crabs exposed to light pollution at night may experience increased perceived predation risk, adjusting their behaviour to compensate for the increased conspicuousness. However, reduced boldness could lead to lower rates of foraging and this, in combination with elevated metabolic rate, has the potential for a reduction in energy balance.

Dominance Hierarchies in Marine Invertebrates

AbstractDominance hierarchies have been well studied in myriad terrestrial animals, but surprisingly little is known about hierarchies in marine invertebrates; examples are limited to a few species of decapod crustaceans and cephalopods. Is the marine environment less conducive to the establishment of dominance hierarchy structures, or does this just underline the lack of detailed behavioral information about most marine invertebrates? In this review, we highlight the published information about marine invertebrate dominance hierarchies, which involve ranks established through fights or displays. We focus on the method of hierarchy formation, examine the ecological implications of this population structure, and compare the habitat and behavioral characteristics of species that exhibit this behavior. Because dominance hierarchies can influence habitat use, population distributions, energetics, mating, resource exploitation, and population genetic structure, it is crucial to understand how this trait evolves and which species are likely to exhibit it. A better understanding of marine invertebrate hierarchies could change the way we think about population dynamics of some species and could have important implications for fisheries, conservation, or even modeling of social and economic inequality.

Three methodological core issues of comparative personality research

Comparative personality research in human and nonhuman species advances many areas of empirical and theoretical research. The methodological foundations underlying these attempts to explain personality, however, remain an unpopular and often ignored topic. The target paper and this rejoinder explore three methodological core issues in the philosophy of science for comparative personality research: Conceptualising personality variation, identifying domains of variation and measuring variation. Clear distinctions among these issues may help to avoid misunderstandings among different disciplines concerned with personality. Copyright © 2008 John Wiley & Sons, Ltd.

Cephalopod Biology: At the Intersection Between Genomic and Organismal Novelties

Cephalopods are resourceful marine predators that have fascinated generations of researchers as well as the public owing to their advanced behavior, complex nervous system, and significance in evolutionary studies. Recent advances in genomics have accelerated the pace of cephalopod research. Many traditional areas focusing on evolution, development, behavior, and neurobiology, primarily on the morphological level, are now transitioning to molecular approaches. This review addresses the recent progress and impact of genomic and other molecular resources on research in cephalopods. We outline several key directions in which significant progress in cephalopod research is expected and discuss its impact on our understanding of the genetic background behind cephalopod biology and beyond.

New bobtail squid (Sepiolidae: Sepiolinae) from the Ryukyu islands revealed by molecular and morphological analysis

Bobtail squid are emerging models for host-microbe interactions, behavior, and development, yet their species diversity and distribution remain poorly characterized. Here, we combine mitochondrial and transcriptome sequences with morphological analysis to describe three species of bobtail squid (Sepiolidae: Sepiolinae) from the Ryukyu archipelago, and compare them with related taxa. One Ryukyuan type was previously unknown, and is described here as Euprymna brenneri sp. nov. Another Ryukyuan type is morphologically indistinguishable from Sepiola parva Sasaki, 1913. Molecular analyses, however, place this taxon within the genus Euprymna Steenstrup, 1887, and additional morphological investigation led to formal rediagnosis of Euprymna and reassignment of this species as Euprymna parva comb. nov. While no adults from the third Ryukyuan type were found, sequences from hatchlings suggest a close relationship with E. pardalota Reid, 2011, known from Australia and East Timor. The broadly sampled transcriptomes reported here provide a foundation for future phylogenetic and comparative studies.

Personality and the collective: bold homing pigeons occupy higher leadership ranks in flocks

While collective movement is ecologically widespread and conveys numerous benefits on individuals, it also poses a coordination problem: who controls the group's movements? The role that animal 'personalities' play in this question has recently become a focus of research interest. Although many animal groups have distributed leadership (i.e. multiple individuals influence collective decisions), studies linking personality and leadership have focused predominantly on the group's single most influential individual. In this study, we investigate the relationship between personality and the influence of multiple leaders on collective movement using homing pigeons, Columba livia, a species known to display complex multilevel leadership hierarchies during flock flights. Our results show that more exploratory (i.e. 'bold') birds are more likely to occupy higher ranks in the leadership hierarchy and thus have more influence on the direction of collective movement than less exploratory (i.e. 'shy') birds during both free flights around their lofts and homing flights from a distant site. Our data also show that bold pigeons fly faster than shy birds during solo flights. We discuss our results in light of theories about the evolution of personality, with specific reference to the adaptive value of heterogeneity in animal groups.This article is part of the theme issue 'Collective movement ecology'.

Description of a personality syndrome in a common and invasive ground beetle (Coleoptera: Carabidae)

Animal personality, defined as consistent differences among individuals in their behaviour, is being increasingly studied as it might lead to a new understanding of the evolution of behaviours. Despite a clear interest in studying personality in a wide range of taxa for comparative analyses, studies on invertebrates are still scarce. Here, we investigated the personality of a ground beetle, Nebria brevicollis, which is widespread in Europe and invasive in North America. We measured seven behavioural traits from an array of three different tests: (i) activity and exploration related traits; (ii) reaction to a threat, and (iii) phototaxis. The repeatability was tested by measuring all behaviours twice, on different days. All behavioural traits were consistent through time, highlighting the presence of personality in the beetle. In addition, we analysed the relationship between the different traits and highlighted two clusters of behaviours (behavioural syndrome), one grouping activity, exploration and boldness traits, and a second one consisting of responses to a threat. This study is the first to our knowledge to provide evidence for personality dimensions within the vast group of the Carabidae. It also constitutes a preliminary step in the experimental investigation of the importance of animal personality in invasive species.

Variability in the "stereotyped" prey capture sequence of male cuttlefish (Sepia officinalis) could relate to personality differences

Studies of animal personality have shown consistent between-individual variation in behaviour in many social and non-social contexts, but hunting behaviour has been overlooked. Prey capture sequences, especially in invertebrates, are supposed to be quite invariant. In cuttlefish, the attack includes three components: attention, positioning, and seizure. The previous studies indicated some variability in these components and we quantified it under the hypothesis that it could relate to personality differences. We, therefore, analysed predation sequences of adult cuttlefish to test their association with personality traits in different contexts. Nineteen subjects were first exposed to an "alert" and a "threat" test and then given a live prey, for 10 days. Predation sequences were scored for components of the attack, locomotor and postural elements, body patterns, and number of successful tentacle ejections (i.e. seizure). PCA analysis of predatory patterns identified three dimensions accounting for 53.1%, 15.9%, and 9.6% of the variance and discriminating individuals based on "speed in catching prey", "duration of attack behaviour", and "attention to prey". Predation rate, success rate, and hunting time were significantly correlated with the first, second, and third PCA factors, respectively. Significant correlations between capture patterns and responsiveness in the alert and threat tests were found, highlighting a consistency of prey capture patterns with measures of personality in other contexts. Personality may permeate even those behaviour patterns that appear relatively invariant.

Ontogenetic and Experience-Dependent Changes in Defensive Behavior in Captive-Bred Hawaiian Bobtail Squid, Euprymna scolopes

Cephalopod molluscs are known for their extensive behavioral repertoire and their impressive learning abilities. Their primary defensive behaviors, such as camouflage, have received detailed study, but knowledge is limited to intensive study of relatively few species. A considerable challenge facing cephalopod research is the need to establish new models that can be captive bred, are tractable for range of different experimental procedures, and that will address broad questions in biological research. The Hawaiian Bobtail Squid (Euprymna scolopes) is a small, tropical cephalopod that has a long history of research in the field of microbial symbiosis, but offers great promise as a novel behavioral and neurobiological model. It can be bred in the laboratory through multiple generations, one of the few species of cephalopod that can meet this requirement (which is incorporated in regulations such as EU directive 2010/63/EU). Additionally, laboratory culture makes E. scolopes an ideal model for studying ontogeny- and experience-dependent behaviors. In this study, we show that captive bred juvenile and adult E. scolopes produce robust, repeatable defensive behaviors when placed in an exposed environment and presented with a visual threat. Further, adult and juvenile squid employ different innate defensive behaviors when presented with a size-matched model predator. When a 10-min training procedure was repeated over three consecutive days, defensive behaviors habituated in juvenile squid for at least 5 days after training, but memory did not appear to persist for 14 days. In contrast, adult squid did not show any evidence of long-term habituation memory. Thus we conclude that this species produces a range of quantifiable, modifiable behaviors even in a laboratory environment where ecologically-relevant, complex behavioral sequences may not reliably occur. We suggest that the lack of long-term memory in adult squid may be related to their less escalated initial response to the mimic, and thus indicates less motivation to retain memory and not necessary inability to form memory. This is the first demonstration of age-related differences in defensive behaviors in Euprymna, and the first record of habituation in this experimentally tractable genus of squid.

The Digestive Tract of Cephalopods: Toward Non-invasive In vivo Monitoring of Its Physiology

Ensuring the health and welfare of animals in research is paramount, and the normal functioning of the digestive tract is essential for both. Here we critically assess non- or minimally-invasive techniques which may be used to assess a cephalopod's digestive tract functionality to inform health monitoring. We focus on: (i) predatory response as an indication of appetitive drive; (ii) body weight assessment and interpretation of deviations (e.g., digestive gland weight loss is disproportionate to body weight loss in starvation); (iii) oro-anal transit time requiring novel, standardized techniques to facilitate comparative studies of species and diets; (iv) defecation frequency and analysis of fecal color (diet dependent) and composition (parasites, biomarkers, and cytology); (v) digestive tract endoscopy, but passage of the esophagus through the brain is a technical challenge; (vi) high resolution ultrasound that offers the possibility of imaging the morphology of the digestive tract (e.g., food distribution, indigestible residues, obstruction) and recording contractile activity; (vii) needle biopsy (with ultrasound guidance) as a technique for investigating digestive gland biochemistry and pathology without the death of the animal. These techniques will inform the development of physiologically based assessments of health and the impact of experimental procedures. Although intended for use in the laboratory they are equally applicable to cephalopods in public display and aquaculture.

Development of behavioural profile in the Northern common boa (Boa imperator): Repeatable independent traits or personality?

Recent studies of animal personality have focused on its proximate causation and ecological and evolutionary significance in particular, but the question of its development was largely overlooked. The attributes of personality are defined as between-individual differences in behaviour, which are consistent over time (differential consistency) and contexts (contextual generality) and both can be affected by development. We assessed several candidates for personality variables measured in various tests with different contexts over several life-stages (juveniles, older juveniles, subadults and adults) in the Northern common boa. Variables describing foraging/feeding decision and some of the defensive behaviours expressed as individual average values are highly repeatable and consistent. We found two main personality axes-one associated with foraging/feeding and the speed of decision, the other reflecting agonistic behaviour. Intensity of behaviour in the feeding context changes during development, but the level of agonistic behaviour remains the same. The juveniles and adults have a similar personality structure, but there is a period of structural change of behaviour during the second year of life (subadults). These results require a new theoretical model to explain the selection pressures resulting in this developmental pattern of personality. We also studied the proximate factors and their relationship to behavioural characteristics. Physiological parameters (heart and breath rate stress response) measured in adults clustered with variables concerning the agonistic behavioural profile, while no relationship between the juvenile/adult body size and personality concerning feeding/foraging and the agonistic behavioural profile was found. Our study suggests that it is important for studies of personality development to focus on both the structural and differential consistency, because even though behaviour is differentially consistent, the structure can change.

Hunger enhances consistent economic choices in non-human primates

Hunger and thirst are fundamental biological processes that drive consumption behavior in humans and non-human animals. While the existing literature in neuroscience suggests that these satiety states change how consumable rewards are represented in the brain, it remains unclear as to how they change animal choice behavior and the underlying economic preferences. Here, I used combined techniques from experimental economics, psychology, and neuroscience to measure food preferences of marmoset monkeys (Callithrix jacchus), a recently developed primate model for neuroscience. Hunger states of animals were manipulated by scheduling feeding intervals, resulting in three different conditions: sated, non-sated, and hungry. During these hunger states, animals performed pairwise choices of food items, which included all possible pairwise combinations of five different food items except for same-food pairs. Results showed that hunger enhanced economic rationality, evident as a decrease of transitivity violations (item A was preferred to item B, and B to C, but C was preferred to A). Further analysis demonstrated that hungry monkeys chose more-preferred items over less-preferred items in a more deterministic manner, while the individual food preferences appeared to remain stable across hunger states. These results suggest that hunger enhances consistent choice behavior and shifts animals towards efficient outcome maximization.

Optimization rating scales for an athletes Socialization Scale by Rasch model

Personality is one of the main psychological aspects that influence athletes performance in competition and one of the most studied subjects in sport psychology. We aimed to optimize item scales in a socialization test based on the big-five model, assessed by means of adjectives and administered to a sample of 225 athletes of both sexes, with 56.9% male. Age ranged from 14-45 years with a mean of 20 (SD = 5,21). Participants attended to basketball (11%), Football (21.8%), Handball (17.3%), Jiu-jitsu (10.2%), tennis (5.60) and Volleyball (16 %) sport modalities. The results indicated that the four point scale were the best item scale structure regarding validity evidences. Hence, this structure could be adopted in this scale aiming better socialization assessment in athletes.

Parental food provisioning is related to nestling stress response in wild great tit nestlings: implications for the development of personality

Background

Variation in early nutrition is known to play an important role in shaping the behavioural development of individuals. Parental prey selection may have long-lasting behavioural influences. In birds foraging on arthropods, for instance, the specific prey types, e.g. spiders and caterpillars, matter as they have different levels of taurine which may have an effect on personality development. Here we investigated how naturally occurring variation in the amounts of spiders and caterpillars, provisioned to nestlings at day 4 and 8 after hatching, is related to the response to handling stress in a wild passerine, the great tit (Parus major). Broods were cross-fostered in a split-brood design allowing us to separate maternal and genetic effects from early rearing effects. Adult provisioning behaviour was monitored on day four and day eight after hatching using video recordings. Individual nestlings were subjected to a handling stress test at an age of 14 days, which is a validated proxy for exploratory behaviour as an adult.

Results

Variation in handling stress was mainly determined by the rearing environment. We show that, contrary to our predictions, not the amount of spider biomass, but the amount of caterpillar biomass delivered per nestling significantly affected individual performance in the stress test. Chicks provisioned with lower amounts of caterpillars exhibited a stronger stress response, reflecting faster exploratory behaviour later on in life, than individuals who received larger amounts of caterpillars.

Conclusions

These results suggest that natural variation in parental behaviour in wild birds modulates the developmental trajectories of their offspring's personality via food provisioning. Since parental provisioning behaviour might also reflect the local environmental conditions, provisioning behaviour may influence how nestlings respond to these local environmental conditions.

Consistent individual differences in haemolymph density reflect risk propensity in a marine invertebrate

While the literature on consistent individual differences in correlated suites of physiological and behavioural traits is steadily growing for vertebrates, invertebrates have received less attention. The few studies that do exist have measured temporary physiological states (or responses), rather than consistent individual physiological traits. Here, I explore the consistency of individual differences in physiology and behaviour of n=53 shore crabs (Carcinus maenas) by repeatedly measuring haemolymph density (HD) and the crabs' responses to a novel environment. In crustaceans, HD is directly proportional to protein concentrations, and thus indicative of physiological condition. HD was highly repeatable, and crabs showed consistent individual differences in their behavioural responses to a novel environment, thus indicating individual consistency in both physiology and behaviour. Furthermore, HD was significantly correlated with the crabs' risk propensity, i.e. individuals with higher HD spent more time near shelter. Overall, this provides the first evidence for consistency in an endogenous physiological trait in an invertebrate. The link between consistent physiology and behaviour, i.e. coping styles, analogous to those found in vertebrates, suggests metabolic and/or immunological correlates of personality which offer great potential for future studies.

Parasites and personality in periwinkles (Littorina littorea): Infection status is associated with mean-level boldness but not repeatability

We demonstrate the presence of animal personality in an inter-tidal gastropod, Littorina littorea, both in a sample of individuals infected by the trematode Cryptocotyle lingua and in an uninfected sample. On average infected individuals behaved more cautiously than individuals free of infection, but the parasite did not affect repeatability. Although the parasite is not associated with greater diversity of behaviour amongst infected individuals, infection might be associated with state-dependent personality differences between infected and non-infected individuals.

Transcriptome analysis of the white body of the squid Euprymna tasmanica with emphasis on immune and hematopoietic gene discovery

In the mutualistic relationship between the squid Euprymna tasmanica and the bioluminescent bacterium Vibrio fischeri, several host factors, including immune-related proteins, are known to interact and respond specifically and exclusively to the presence of the symbiont. In squid and octopus, the white body is considered to be an immune organ mainly due to the fact that blood cells, or hemocytes, are known to be present in high numbers and in different developmental stages. Hence, the white body has been described as the site of hematopoiesis in cephalopods. However, to our knowledge, there are no studies showing any molecular evidence of such functions. In this study, we performed a transcriptomic analysis of white body tissue of the Southern dumpling squid, E. tasmanica. Our primary goal was to gain insights into the functions of this tissue and to test for the presence of gene transcripts associated with hematopoietic and immune processes. Several hematopoiesis genes including CPSF1, GATA 2, TFIID, and FGFR2 were found to be expressed in the white body. In addition, transcripts associated with immune-related signal transduction pathways, such as the toll-like receptor/NF-κβ, and MAPK pathways were also found, as well as other immune genes previously identified in E. tasmanica's sister species, E. scolopes. This study is the first to analyze an immune organ within cephalopods, and to provide gene expression data supporting the white body as a hematopoietic tissue.

Aggressive behavior, brain size and domestication in clonal rainbow trout lines

Domestication causes behavior and brain size changes in many species. We addressed three questions using clonal rainbow trout lines: What are the mirror-elicited aggressive tendencies in lines with varying degrees of domestication? How does brain size relate to genotype and domestication level? Finally, is there a relationship between aggressive behavior and brain size? Clonal lines, although sampling a limited subset of the species variation, provide us with a reproducible experimental system with which we can develop hypotheses for further research. We performed principal component analyses on 12 continuous behavior and brain/body size variables and one discrete behavioral variable ("yawn") and detected several aggression syndromes. Two behaviors, "freeze" and "escape", associated with high domestication; "display" and "yawn" behavior associated with wild lines and "swim against the mirror" behavior associated with semi-wild and domestic lines. Two brain size traits, total brain and olfactory volume, were significantly related to domestication level when taking total body size into account, with domesticated lines having larger total brain volume and olfactory regions. The aggression syndromes identified indicate that future QTL mapping studies on domestication-related traits would likely be fruitful.

An age-structured approach to modelling behavioural variation maintained by life-history trade-offs

There have been numerous empirical studies on the fitness consequences of behavioural syndromes in various animal taxa; however, the ecological and evolutionary implications on a population level are still poorly understood. To better understand these implications, we develop a non-linear age-structured mathematical model to qualitatively examine the evolutionary consequences of a heritable boldness personality trait within an animal population. We assume that this heritable boldness trait is positively correlated with boldness towards predators and intraspecific aggressiveness. This assumption leads to a growth/reproductive success versus mortality trade-off, which is thoroughly investigated and documented in the literature. Another life-history trade-off we include in the model is future versus current reproduction, which was shown by Wolf et al. to be a possible mechanism for the evolution of behavioural syndromes within an animal population. The stability of the system is analysed, whereby the characteristic equation is in the form of a homogeneous Fredholm equation of the second kind which depends on both the perturbation and equilibrium solution. The system is found to be stable due to the competition between individuals of similar boldness acting as a negative feedback mechanism. Using numerical simulations we examine the qualitative features of the solution to the system. In particular, we investigate the interplay between the mutation and competition strength between two individuals with different boldness, whereby we find that an increasing competition range acts to push individuals to both extremes of the shy-bold axis, while an increasing mutation range counteracts this effect. This qualitative trait of aggregation of individuals around the shy and bold extremes is also found when examining different birth, mortality and competition functions.

Transitions during cephalopod life history: the role of habitat, environment, functional morphology and behaviour

Cephalopod life cycles generally share a set of stages that take place in different habitats and are adapted to specific, though variable, environmental conditions. Throughout the lifespan, individuals undertake a series of brief transitions from one stage to the next. Four transitions were identified: fertilisation of eggs to their release from the female (1), from eggs to paralarvae (2), from paralarvae to subadults (3) and from subadults to adults (4). An analysis of each transition identified that the changes can be radical (i.e. involving a range of morphological, physiological and behavioural phenomena and shifts in habitats) and critical (i.e. depending on environmental conditions essential for cohort survival). This analysis underlines that transitions from eggs to paralarvae (2) and from paralarvae to subadults (3) present major risk of mortality, while changes in the other transitions can have evolutionary significance. This synthesis suggests that more accurate evaluation of the sensitivity of cephalopod populations to environmental variation could be achieved by taking into account the ontogeny of the organisms. The comparison of most described species advocates for studies linking development and ecology in this particular group.

Syndromes or flexibility: behavior during a life history transition of a coral reef fish

The theory of behavioral syndromes focuses on quantifying variation in behavior within and among individual organisms and attempts to account for the maintenance of differences in behavior that occur in a consistent manner among individuals. Behavioral syndromes have potentially important ecological consequences (e.g. survivorship tradeoffs) and can be shaped by population dynamics through selective mortality. Here, we search for any evidence for consistency of behavior across situations in juveniles of a common damselfish, Pomacentrus amboinensis (Pomacentridae) at the transition between larval habitats in the plankton and juvenile habitats on the reef. Naïve fish leaving the pelagic phase to settle on reefs were caught by light traps and their behaviors observed using similar methods across three different situations (small aquaria, large aquaria, field setting); all of which represent low risk and well-sheltered environments. Seven behavioral traits were compared within and among individuals across situations to determine if consistent behavioral syndromes existed. No consistency was found in any single or combination of behavioral traits for individuals across all situations. We suggest that high behavioral flexibility is likely beneficial for newly-settled fish at this ontogenetic transition and it is possible that consistent behavioral syndromes are unlikely to emerge in juveniles until environmental experience is gained or certain combinations of behaviors are favored by selective mortality.

Situation and context impacts the expression of personality: the influence of breeding season and test context

Non-human animal personality is defined as consistent behavioural differences across time and situations/contexts. Behaviours are, however, often plastic and to explain how plasticity and personality may coexist an adaptive framework has been developed. Still, there is little information on how personality is impacted by situations and contexts on an individual level. We investigated this in the European mink (Mustela lutreola) by performing a set of five experiments in two situations consisting of non-breeding and breeding season, and by using different test contexts. Three personality trait domains were identified; boldness, exploration and sociability. The levels of boldness and exploration changed between seasons but remained repeatable, which implies behavioural reaction norms and supports that the concept of personality remained applicable despite plasticity. Whilst males became bolder and more explorative in the breeding season females became shyer, which reflects European mink breeding behaviour. Furthermore, behaviours performed in mirror stimulus tests fell into different domains depending on whether, the test was conducted in the own territory or not, suggesting plasticity in the response towards conspecifics. To conclude, our results highlight the importance of situation and context for the expression of personality, and the significance of measuring multiple personality trait domains with several methods.

Cephalopod neurobiology: an introduction for biologists working in other model systems

This paper concisely summarizes major aspects of cephalopod biology, behavior, and ecology providing a backdrop against which neurobiology of these animals can be interpreted. Reproduction, camouflage, motor control, memory, learning, and behavioral ecology are introduced, and thorough literature reviews of these subjects are cited for further reading. The aim of this paper is to provide a general introduction to cephalopods for use by workers currently focused on other model systems.

Personality psychology: lexical approaches, assessment methods, and trait concepts reveal only half of the story--why it is time for a paradigm shift

This article develops a comprehensive philosophy-of-science for personality psychology that goes far beyond the scope of the lexical approaches, assessment methods, and trait concepts that currently prevail. One of the field's most important guiding scientific assumptions, the lexical hypothesis, is analysed from meta-theoretical viewpoints to reveal that it explicitly describes two sets of phenomena that must be clearly differentiated: 1) lexical repertoires and the representations that they encode and 2) the kinds of phenomena that are represented. Thus far, personality psychologists largely explored only the former, but have seriously neglected studying the latter. Meta-theoretical analyses of these different kinds of phenomena and their distinct natures, commonalities, differences, and interrelations reveal that personality psychology's focus on lexical approaches, assessment methods, and trait concepts entails a) erroneous meta-theoretical assumptions about what the phenomena being studied actually are, and thus how they can be analysed and interpreted, b) that contemporary personality psychology is largely based on everyday psychological knowledge, and c) a fundamental circularity in the scientific explanations used in trait psychology. These findings seriously challenge the widespread assumptions about the causal and universal status of the phenomena described by prominent personality models. The current state of knowledge about the lexical hypothesis is reviewed, and implications for personality psychology are discussed. Ten desiderata for future research are outlined to overcome the current paradigmatic fixations that are substantially hampering intellectual innovation and progress in the field.

The adaptive response of protein turnover to the energetic demands of reproduction in a cephalopod

Sourcing energy for reproduction is a major driver of the life-history characteristics of animals. Unlike other molluscs, cephalopods do not appear to have significant glycogen stores, and energy is either sourced directly from ingested food or mobilized from protein stores in the muscle. Given the importance of protein to cephalopods, this study quantified changes in protein turnover in the muscle tissue in reproductively immature and maturing/mature individuals. Quantifying protein accretion and protein synthesis allowed an assessment of protein turnover in immature and maturing individuals of the southern dumpling squid (Euprymna tasmanica), which has fast nonasymptotic growth, has a short generation time, and does not use lipid stores. This study found that protein turnover slowed in the mantle muscle tissue with gonad growth, suggesting an adaptive response to the energy demands associated with reproduction but one that allows for continued somatic growth and muscle function in these animals. However, the cost of reproduction may be indirect, with less energy available for somatic repair, and therefore may be responsible for the rapid senescence typical of many cephalopod species.

Personality assessment and its association with genetic factors in captive Asian and African elephants

Elephants live in a complex society based on matrilineal groups. Management of captive elephants is difficult, partly because each elephant has a unique personality. For a better understanding of elephant well being in captivity, it would be helpful to systematically evaluate elephants' personalities and their underlying biological basis. We sent elephant' personality questionnaires to keepers of 75 elephants. We also used 196 elephant DNA samples to search for genetic polymorphisms in genes expressed in the brain that have been suggested to be related to personality traits. Three genes, androgen receptor (AR), fragile X related mental retardation protein interacting protein (NUFIP2), and acheate-scute homologs 1 (ASH1) contained polymorphic regions. We examined the association of personality with intraspecific genetic variation in 17 Asian and 28 African elephants. The results suggest that the ASH1 genotype was associated with neuroticism in Asian elephants. Subjects with short alleles had lower scores of neuroticism than those with long alleles. This is the first report of an association between a genetic polymorphism and personality in elephants.