Shade as enrichment : testing preferences for shelter in two model fish species

N.A.R.J. was supported by an Fisheries Society of the British Isles studentship, F.M.J. by the St Andrews School of Biology and H.C.S.-J. by the John Templeton Foundation.We compared preferences shown by zebrafish Danio rerio and three‐spined stickleback Gasterosteus aculeatus for shelter provided by above‐tank shade and artificial plants. Zebrafish showed no preference for either shelter, whereas sticklebacks showed a preference for both shelter types over open areas and for shade over plants. Our results suggest shade may be used as enrichment for captive fish and re‐emphasise the importance of species‐specific welfare considerations.PostprintPeer reviewe

Passive traps and sampling bias: social effects and personality affect trap-entry by sticklebacks

This research was funded by the University of St Andrews.Researchers routinely quantify the behaviour of subsets of animals, using their findings to make inferences about wider populations. Broader conclusions, however, may be inaccurate if the subjects that are tested are not representative of these populations. One way that this can arise is through sampling bias, which can occur if the method of collecting the test subjects disproportionately selects those with particular attributes, such that they end up being over‐ or under represented within the sample. Passive traps are associated with such sampling biases and have been shown to target certain behavioural phenotypes in a range of species. Here we asked whether funnel‐type fish traps were more likely to target more active and more social sticklebacks (Gasterosteus aculeatus). We found that more subjects entered the traps when they already contained conspecifics and that individual measures of activity predicted trap entry, with more active fish being captured sooner both when the traps already contained conspecifics and when they were empty. Unexpectedly, less‐social fish were captured sooner when the traps contained conspecifics. Sampling biases have the potential to skew the data collected by researchers and we therefore highlight the need to acknowledge and discuss potential for sampling biases and any consequences that may arise from this in published work. In the longer term, research that estimates the potential for sampling biases for various collection methods and species would be a valuable resource for helping to devise more representative sampling designs.Publisher PDFPeer reviewe

Rank-related contrasts in longevity arise from extra-group excursions not delayed senescence in a cooperative mammal

In many cooperatively breeding animal societies, breeders outlive non-breeding subordinates, despite investing heavily in reproduction [1-3]. In eusocial insects, the extended lifespans of breeders arise from specialized slowed aging profiles [1], prompting suggestions that reproduction and dominance similarly defer aging in cooperatively breeding vertebrates, too [4-6]. Although lacking the permanent castes of eusocial insects, breeders of vertebrate societies could delay aging via phenotypic plasticity (similar rank-related changes occur in growth, neuroendocrinology, and behavior [7-10]), and such plastic deferment of aging may reveal novel targets for preventing aging-related diseases [11]. Here, we investigate whether breeding dominants exhibit extended longevity and delayed age-related physiological declines in wild cooperatively breeding meerkats. We show that dominants outlive subordinates but exhibit faster telomere attrition (a marker of cellular senescence and hallmark of aging [12]) and that in dominants (but not subordinates), rapid telomere attrition is associated with mortality. Our findings further suggest that, rather than resulting from specialized aging profiles, differences in longevity between dominants and subordinates are driven by subordinate dispersal forays, which become exponentially more frequent with age and increase subordinate mortality. These results highlight the need to critically examine the causes of rank-related longevity contrasts in other cooperatively breeding vertebrates, including social mole-rats, where they are currently attributed to specialized aging profiles in dominants [4]

Reproductive conflict resolution in cooperative breeders

Female infanticide is common in animal societies where groups comprise multiple co-breeding females. To reduce the risk that their offspring are killed, mothers can synchronize breeding and pool offspring, making it hard for females to avoid killing their own young. However, female reproductive conflict does not invariably result in reproductive synchrony, and we lack a general hypothesis explaining the variation in conflict resolution strategies seen across species. Here, we investigate the fitness consequences of birth timing relative to other females and the prevalence of birth synchrony in cooperatively breeding Kalahari meerkats (Suricata suricatta). We show that, although there would be substantial benefits to females in synchronizing births and reducing their risk of infanticide, birth synchrony is rare. Since precise breeding synchrony has evolved in a related species with similar infanticidal female reproductive conflict, its absence in meerkats requires an evolutionary explanation. We therefore explore the costs and benefits of synchronizing breeding in two theoretical models, each of which contrasts synchrony with an alternative reproductive strategy: (i) breeding opportunistically and accepting fitness losses to infanticide or (ii) suppressing the reproduction of others to prevent infanticide. Our models show that the costs of synchrony constrain its development if subordinates breed infrequently, and that selection instead favors the suppression of subordinate reproduction by the dominant and opportunistic reproduction by subordinates. Together, our results suggest that the resolution of reproductive conflict in animal societies is shaped by differential breeding propensities among female group members, leading to divergent conflict resolution strategies even in closely related species.A European Research Council grant to T.C.-B. (#294494). A. J. was supported by a Henslow Fellowship jointly provided by the Cambridge Philosophical Society and Hughes Hall, Cambridge. The Kalahari Meerkat Project is supported by the Universities of Cambridge, Zurich and Pretoria.https://academic.oup.com/beheco2020-08-29hj2020Mammal Research InstituteZoology and Entomolog

Reproductive conflict resolution in cooperative breeders

Female infanticide is common in animal societies where groups comprise multiple co-breeding females. To reduce the risk that their offspring are killed, mothers can synchronize breeding and pool offspring, making it hard for females to avoid killing their own young. However, female reproductive conflict does not invariably result in reproductive synchrony, and we lack a general hypothesis explaining the variation in conflict resolution strategies seen across species. Here, we investigate the fitness consequences of birth timing relative to other females and the prevalence of birth synchrony in cooperatively breeding Kalahari meerkats (Suricata suricatta). We show that, although there would be substantial benefits to females in synchronizing births and reducing their risk of infanticide, birth synchrony is rare. Since precise breeding synchrony has evolved in a related species with similar infanticidal female reproductive conflict, its absence in meerkats requires an evolutionary explanation. We therefore explore the costs and benefits of synchronizing breeding in two theoretical models, each of which contrasts synchrony with an alternative reproductive strategy: (i) breeding opportunistically and accepting fitness losses to infanticide or (ii) suppressing the reproduction of others to prevent infanticide. Our models show that the costs of synchrony constrain its development if subordinates breed infrequently, and that selection instead favors the suppression of subordinate reproduction by the dominant and opportunistic reproduction by subordinates. Together, our results suggest that the resolution of reproductive conflict in animal societies is shaped by differential breeding propensities among female group members, leading to divergent conflict resolution strategies even in closely related species.A European Research Council grant to T.C.-B. (#294494). A. J. was supported by a Henslow Fellowship jointly provided by the Cambridge Philosophical Society and Hughes Hall, Cambridge. The Kalahari Meerkat Project is supported by the Universities of Cambridge, Zurich and Pretoria.https://academic.oup.com/beheco2020-08-29hj2020Mammal Research InstituteZoology and Entomolog

The influence of stress hormones and aggression on cooperative behaviour in subordinate meerkats

In cooperative breeders, aggression from dominant breeders directed at subordinates may raise subordinate stress hormone (glucocorticoid) concentrations. This may benefit dominants by suppressing subordinate reproduction but it is uncertain whether aggression from dominants can elevate subordinate cooperative behaviour, or how resulting changes in subordinate glucocorticoid concentrations affect their cooperative behaviour. We show here that the effects of manipulating glucocorticoid concentrations in wild meerkats (Suricata suricatta) on cooperative behaviour varied between cooperative activities as well as between the sexes. Subordinates of both sexes treated with a glucocorticoid receptor antagonist (mifepristone) exhibited significantly more pup protection behaviour (babysitting) compared to those treated with glucocorticoids (cortisol) or controls. Females treated with mifepristone had a higher probability of exhibiting pup food provisioning (pup-feeding) compared to those treated with cortisol. In males, there were no treatment effects on the probability of pup-feeding, but those treated with cortisol gave a higher proportion of the food they found to pups than those treated with mifepristone. Using 19 years of behavioural data, we also show that dominant females did not increase the frequency with which they directed aggression at subordinates at times when the need for assistance was highest. Our results suggest that it is unlikely that dominant females manipulate the cooperative behaviour of subordinates through the effects of aggression on their glucocorticoid levels and that the function of aggression directed at subordinates is probably to reduce the probability they will breed

Interpretation of ambiguous situations: evidence for a dissociation between social and physical threat in Williams syndrome

There is increasing evidence that Williams syndrome (WS) is associated with elevated anxiety that is non-social in nature, including generalised anxiety and fears. To date very little research has examined the cognitive processes associated with this anxiety. In the present research, attentional bias for non-social threatening images in WS was examined using a dot-probe paradigm. Participants were 16 individuals with WS aged between 13 and 34 years and two groups of typically developing controls matched to the WS group on chronological age and attentional control ability respectively. The WS group exhibited a significant attention bias towards threatening images. In contrast, no bias was found for group matched on attentional control and a slight bias away from threat was found in the chronological age matched group. The results are contrasted with recent findings suggesting that individuals with WS do not show an attention bias for threatening faces and discussed in relation to neuroimaging research showing elevated amygdala activation in response to threatening non-social scenes in WS

CNS-PNETs with C19MC amplification and/or LIN28 expression comprise a distinct histogenetic diagnostic and therapeutic entity

Amplification of the C19MC oncogenic miRNA cluster and high LIN28 expression has been linked to a distinctly aggressive group of cerebral CNS-PNETs (group 1 CNS-PNETs) arising in young children. In this study, we sought to evaluate the diagnostic specificity of C19MC and LIN28, and the clinical and biological spectra of C19MC amplified and/or LIN28+ CNS-PNETs. We interrogated 450 pediatric brain tumors using FISH and IHC analyses and demonstrate that C19MC alteration is restricted to a sub-group of CNS-PNETs with high LIN28 expression; however, LIN28 immunopositivity was not exclusive to CNS-PNETs but was also detected in a proportion of other malignant pediatric brain tumors including rhabdoid brain tumors and malignant gliomas. C19MC amplified/LIN28+ group 1 CNS-PNETs arose predominantly in children <4 years old; a majority arose in the cerebrum but 24 % (13/54) of tumors had extra-cerebral origins. Notably, group 1 CNS-PNETs encompassed several histologic classes including embryonal tumor with abundant neuropil and true rosettes (ETANTR), medulloepithelioma, ependymoblastoma and CNS-PNETs with variable differentiation. Strikingly, gene expression and methylation profiling analyses revealed a common molecular signature enriched for primitive neural features, high LIN28/LIN28B and DNMT3B expression for all group 1 CNS-PNETs regardless of location or tumor histology. Our collective findings suggest that current known histologic categories of CNS-PNETs which include ETANTRs, medulloepitheliomas, ependymoblastomas in various CNS locations, comprise a common molecular and diagnostic entity and identify inhibitors of the LIN28/let7/PI3K/mTOR axis and DNMT3B as promising therapeutics for this distinct histogenetic entity. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00401-014-1291-1) contains supplementary material, which is available to authorized users

Understanding 'non-genetic' inheritance : insights from molecular-evolutionary crosstalk

The idea for this paper was initially proposed by I.A.-K. and was further developed by all authors in a workshop generously funded by grant No 789240 from the European Research Council (ERC) to F.J.W. S.E.S. acknowledges support from Wesleyan University and The John Templeton Foundation.Understanding the evolutionary and ecological roles of 'non-genetic' inheritance (NGI) is daunting due to the complexity and diversity of epigenetic mechanisms. We draw on insights from molecular and evolutionary biology perspectives to identify three general features of 'non-genetic' inheritance systems: (i) they are functionally interdependent with, rather than separate from, DNA sequence; (ii) precise mechanisms vary phylogenetically and operationally; and (iii) epigenetic elements are probabilistic, interactive regulatory factors and not deterministic 'epialleles' with defined genomic locations and effects. We discuss each of these features and offer recommendations for future empirical and theoretical research that implements a unifying inherited gene regulation (IGR) approach to studies of 'non-genetic' inheritance.Publisher PDFPeer reviewe