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Although there have been continuous improvements in child oral health over recent decades, first permanent molars (FPMs) remain susceptible to early caries and can often be affected by hypomineralisation. We highlight current thinking in caries management and the restoration of hypomineralised FPMs, while also discussing enforced loss of these teeth within the context of interceptive extractions or extractions as part of orthodontic treatment. Compromised FPMs can negatively impact on quality of life for a child and present significant management challenges for the dental team. Although a high-quality evidence base is lacking for the different treatment options, early diagnosis and multidisciplinary treatment planning are key to achieving the best outcomes.

Progress in paediatric dentistry over the last half a century has been evident across all areas of the speciality. This article highlights significant changes in the diagnosis, prevention and management of dental caries, traumatic dental injuries, developmental enamel defects, tooth erosion, dental fear and anxiety and safeguarding children. The dedication of clinicians and researchers along with advances in material science and technology have supported this progress. We discuss the importance of working with those both within and outside of the specialty in order to collaborate to improve children’s oral health. There have been significant strides in the provision of child-centred holistic care and research. Reviewing the advancements made over this period has set a high precedent for making further progress within paediatric dentistry over the next 50 years. CPD/Clinical Relevance: Knowledge of key advances in the field of paediatric dentistry will facilitate good diagnosis and treatment of younger patients.

Introduction Silver diammine fluoride (SDF) is a relatively recent introduction to clinical practice in the UK as a caries management option for children’s primary teeth. However, implementation and uptake are likely to be improved by the availability of child focused information, which is key to ensuring that children understand information about their treatment choices. This study engaged children to co-produce an information video about SDF and explored other children’s opinions about the video. Methods A video was co-produced with children that explained caries management options with a focus on SDF. Children created the content and had substantial input into the editing process. Qualitative semi-structured interviews were carried out with 16 children, aged 4–8 years, based on a topic guide to explore their views on the video. Framework analysis was then performed. Results The video was viewed positively overall although participants did offer diverse views on some specific aspects. The data could be summarised through the following themes: video style and format, caries specific information and views on SDF. Conclusions Our study showed that children recognise the value and utility of an information video co-produced by their peers for provision of information about SDF as a caries management option.

Shoaling, the formation of social groupings in fish, can provide benefits including reduced predation risk. However, it can also inflict costs including increased competition for resources, transmission of parasites, and salience to predators. Trinidadian guppies exhibit inter-population variation in shoaling behavior where individuals coexisting with large piscivorous predators (high predation localities) spend most of their time in shoals and those coexisting with an ambush predator, Rivulus hartii (recently, Anablepsoides hartii), that preys primarily on smaller guppies (low predation localities) do not. It has been suggested that this predator selects for reduced shoaling because doing so reduces salience to the predator. Here, as far as we know, we perform the first test of this idea. First, we investigated the effectiveness of shoaling in encounters with this predator. In survival trials, where one rivulus interacted with a group of guppies, we found that the predator was more likely to attack individuals in shoals than singletons. However, we also found that attacks directed at shoals were less likely to succeed. This suggests that the optimal strategy for guppies co-existing with this predator is to reduce shoaling to reduce the probability of being attacked, and to form shoals when an attack is initiated. We then asked if guppies modified their shoaling behavior in response to visual and olfactory cues from this predator during development. We found changes in guppy behavior in response to the treatment: guppies increased shoaling behavior when there was heightened risk of predation.

Background Globally, around 13% of children experience dental anxiety (DA). This group of patients frequently miss dental appointments, have greater reliance on treatment under general anaesthesia (GA) and have poorer oral health-related quality of life (OHRQoL) than their non-dentally anxious peers. Recently, a low-intensity cognitive behavioural therapy (CBT)-based, self-help approach has been recommended for management of childhood anxiety disorders. A feasibility study conducted in secondary care found this guided self-help CBT resource reduced DA and a randomised controlled trial was recommended. The present study aims to establish the clinical and cost-effectiveness of a guided self-help CBT intervention to reduce DA in children attending primary dental care sites compared to usual care. Methods This 4-year randomised controlled trial will involve 600 children (aged 9–16 years) and their parent/carers in 30 UK primary dental care sites. At least two dental professionals will participate in each site. They will be assigned, using random allocation, to receive the CBT training and deliver the intervention or to deliver usual care. Children with DA attending these sites, in need of treatment, will be randomly allocated to be treated either by the intervention (CBT) or control (usual care) dental professional. Children will complete questionnaires relating to DA, OHRQoL and HRQoL before treatment, immediately after treatment completion and 12 months post-randomisation. Attendance, need for sedation/GA and costs of the two different approaches will be compared. The primary outcome, DA, will be measured using the Modified Child Dental Anxiety Scale. Scores will be compared between groups using a linear mixed model. Discussion Treating dentally anxious patients can be challenging and costly. Consequently, these children are frequently referred to specialist services for pharmacological interventions. Longer waiting times and greater travel distances may then compound existing healthcare inequalities. This research will investigate whether the intervention has the potential to reduce DA and improve oral health outcomes in children over their life-course, as well as upskilling primary dental healthcare professionals to better manage this patient group. Trial registration This clinical trial has been registered with an international registry and has been allocated an International Standard Randomised Controlled Trial Number (ISRCTN27579420).

Color variation is one of the most obvious examples of variation in nature, but biologically meaningful quantification and interpretation of variation in color and complex patterns are challenging. Many current methods for assessing variation in color patterns classify color patterns using categorical measures and provide aggregate measures that ignore spatial pattern, or both, losing potentially important aspects of color pattern.Here, we present Colormesh, a novel method for analyzing complex color patterns that offers unique capabilities. Our approach is based on unsupervised color quantification combined with geometric morphometrics to identify regions of putative spatial homology across samples, from histology sections to whole organisms. Colormesh quantifies color at individual sampling points across the whole sample.We demonstrate the utility of Colormesh using digital images of Trinidadian guppies (Poecilia reticulata), for which the evolution of color has been frequently studied. Guppies have repeatedly evolved in response to ecological differences between up‐ and downstream locations in Trinidadian rivers, resulting in extensive parallel evolution of many phenotypes. Previous studies have, for example, compared the area and quantity of discrete color (e.g., area of orange, number of black spots) between these up‐ and downstream locations neglecting spatial placement of these areas. Using the Colormesh pipeline, we show that patterns of whole‐animal color variation do not match expectations suggested by previous work.Colormesh can be deployed to address a much wider range of questions about color pattern variation than previous approaches. Colormesh is thus especially suited for analyses that seek to identify the biologically important aspects of color pattern when there are multiple competing hypotheses or even no a priori hypotheses at all., There is considerable interest in quantifying color patterns in order to investigate the role that color plays in ecological and evolutionary processes, including competition, mate choice, kin selection, predation, and speciation. The Colormesh approach is a novel, unsupervised method for sampling color from digital images, enabling highly multivariate quantification of color patterns. We demonstrate the utility of the Colormesh approach by evaluating patterns of color variation in the Trinidadian guppy, a model system for studies of the role of color in local adaptation and in the maintenance of genetic diversity.

Design This was a non-blinded multiple-site randomised controlled clinical trial.Case selection Children, aged 5-6 years, were recruited from 11 government-funded kindergartens (pre-schools) in Selangor, Malaysia. The kindergartens were randomly allocated to either the Intervention Group (n = 185 children) or the Control Group (n = 142 children). A clinical examination was conducted to determine the participants' baseline caries experience. Over a 24-month period (commencing in 2015), the Intervention Group received six -monthly dental home visits (DHVs) to provide the families with oral hygiene and dietary instruction, along with educational leaflets. The Control Group received only the educational leaflets. Caries incidence was measured in terms of both the proportion of children who developed new carious lesions, and the number of primary molars in which new carious lesions were seen at 24 months.Data analysis A chi-squared test was used to compare baseline socioeconomic characteristics as well as the proportion of children in each arm who developed new carious lesions. A t-test was used to compare the mean number of primary molars that developed new caries in each group. In addition, the number needed to treat (NNT) was determined.Results There was a 70% (n = 132) and 71% (n = 100) completion rate for participants in the Intervention and Control Groups, respectively. At 24 months, the key finding was that significantly fewer children in the Intervention Group (14.4%; n = 19) had developed new caries lesions compared to the Control Group (60%; n = 60) (p = 0.001). The NNT was calculated as 2.2, to prevent new caries in one child. After controlling for parental education level and household crowding, children in the Control Group were 8.2 times more likely to develop caries in their primary molars than those in the Intervention Group.Conclusions The authors concluded that in a middle-income country such as Malaysia, six -monthly dental home visits are an effective caries prevention strategy for children aged 5-6 years old from low-income families.

Objective To examine the impact of clinical, individual, and environmental factors on children’s oral health-related quality of life (OHRQoL) and overall health-related quality of life (HRQoL) following dental caries management under general anaesthetic (GA). Methods Participants comprised 5- to 16-year-old children who were referred to a British Dental Hospital, for the management of their dental caries under GA. The Caries Impacts and Experiences Questionnaire for Children (CARIES-QC) and the Child Health Utility 9D (CHU9D) were used to assess child-reported OHRQoL and HRQoL, respectively, at baseline and 3-months follow up. A theoretical conceptual model, based on the Wilson and Cleary model of HRQOL, was evaluated using path analysis to explore indirect and direct relationships of the clinical, individual, and environmental variables on the quality of life outcomes following treatment. Results 85 children completed the study. Path analyses revealed that 47% of the variance in OHRQoL scores was accounted for by the variables in the model. There were significant relationships between change in OHRQoL score and treatment type [extraction only vs. combination care (β = 1.41, p = 0.07)] and number of extractions (β = 0.46, p Conclusions Treatment type, via number of extractions, may significantly impact on child OHRQoL and HRQoL following treatment under GA. However, to identify any other factors, that might affect these key outcomes, further enquiry is warranted with a bigger sample.

How genetic variation is maintained in ecologically important traits is a central question in evolutionary biology. Male Trinidadian guppies, Poecilia reticulata, exhibit high genetic diversity in color patterns within populations, and field and laboratory studies implicate negative frequency-dependent selection in maintaining this variation. However, behavioral and ecological processes that mediate this selection in natural populations are poorly understood. We evaluated female mate preference in 11 natural guppy populations, including paired populations from high- and low-predation habitats, to determine if this behavior is responsible for negative frequency-dependent selection and to evaluate its prevalence in nature. Females directed significantly more attention to males with rare and unfamiliar color patterns than to males with common patterns. Female attention also increased with the area of male orange coloration, but this preference was independent of the preference for rare and unfamiliar patterns. We also found an overall effect of predation regime; females from high-predation populations directed more attention toward males than those from low-predation populations. Again, however, the habitat-linked preference was statistically independent from the preference for rare and unfamiliar patterns. Because previous research indicates that female attention to males predicts male mating success, we conclude that the prevalence of female preference for males with rare and unfamiliar color patterns across many natural populations supports the hypothesis that female preference is an important process underlying the maintenance of high genetic variation in guppy color patterns.

Kin recognition plays an important role in social behavior and evolution, but the proximate mechanisms by which individuals recognize kin remain poorly understood. In many species, individuals form a "kin template" that they compare with conspecifics' phenotypes to assess phenotypic similarity-and, by association, relatedness. Individuals may form a kin template through self-inspection (i.e., self-referencing) and/or by observing their rearing associates (i.e., family referencing). However, despite much interest, few empirical studies have successfully disentangled self-referencing and family referencing. Here, we employ a novel set of breeding crosses using the Trinidadian guppy (

Evidence is emerging that fathers can have nongenetic effects on the phenotypes of their offspring. Most studies have focused on the role that nongenetic modifications to sperm can have on offspring phenotype; however, fathers can also have nongenetic effects on offspring through their interactions with females, called female-mediated paternal effects. These effects can occur in situations where male phenotype, e.g. behaviour or morphology, affects female stress and/or provisioning of offspring. These effects are potentially widespread, but few studies have explicitly investigated the role of female-mediated paternal effects on offspring phenotype. Here, we asked if male mating interactions can affect offspring via female mediated paternal effects in the Trinidadian guppy, Poecilia reticulata. To do this, we manipulated mating behaviour by: (i) administering a drug known to affect the neurotransmitter dopamine, and (ii) varying the familiarity of potential mates, which affects attractiveness in this species. With these treatments, we successfully manipulated the mating behaviour of male guppies and female preference for those males. Further, we found significant effects of sire mating behaviour, sire drug treatment, and parental familiarity status on behavioural measures of offspring anxiety in response to a novel object. Because Control offspring of 'familiar' and 'unfamiliar' pairs differed in their behaviour, our results cannot be solely attributed to potential nongenetic modifications to sperm caused by the drug. These results emphasize the importance of female-mediated paternal effects, including those caused by altered male mating behaviour, in shaping offspring phenotype.

Color variation is one of the most obvious examples of variation in nature. Objective quantification and interpretation of variation in color and complex patterns is challenging. Assessment of variation in color patterns is limited by the reduction of color into categorical measures and lack of spatial information. We present Colormesh as a novel method for analyzing complex color patterns that offers unique capabilities. Compared to other methods, Colormesh maintains the continuous measure of color at individual sampling points throughout the pattern. This is particularly useful for analyses of variation in color patterns, whether interest is in specific locations or the pattern as a whole. In our approach, the use of Delaunay triangulation to determine sampling location eliminates the need for color patterns to have clearly defined pattern elements, and users are not required to identify discrete color categories. This method is complementary to several other methods available for color pattern quantification, and can be usefully deployed to address a wide range of questions about color pattern variation.

Kin recognition plays an important role in social evolution, but the proximate mechanisms by which individuals recognize kin remain poorly understood. In many species, individuals form a “kin template” that they compare against conspecifics’ phenotypes to assess phenotypic similarity–and by association, relatedness. Individuals may form a kin template through self-inspection (i.e. self-referencing) and/or by observing their rearing associates (i.e. family-referencing). However, despite much interest, few empirical studies have successfully disentangled self- and family-referencing. Here, we use a novel set of breeding crosses in the Trinidadian guppy (Poecilia reticulata) to definitively disentangle referencing systems by manipulating exposure to kin from conception onwards. We show that guppies discriminate among their full- and maternal half-siblings, which can only be explained by self-referencing. Additional behavioral experiments revealed no evidence that guppies incorporate the phenotypes of their broodmates or mother into the kin template. Finally, by manipulating the format of our behavioral tests, we show that olfactory communication is both necessary and sufficient for kin discrimination. These results demonstrate that individuals recognize kin by comparing the olfactory phenotypes of conspecifics against their own. This study resolves key questions about the proximate mechanisms underpinning kin recognition, with implications for the ontogeny and evolution of social behavior.

Additional file 5:Distribution of p-values from transcript-specific generalized linear models testing. (DOCX 33 KB)

Understanding the impact of barriers and habitat fragmentation on the ecology and genetics of species is of broad interest to many biologists. In aquatic systems, hydroelectric dams often present an impenetrable barrier to migratory fish and can have negative effects on their persistence. Hydroelectric dams constructed in the Coquitlam and Alouette Rivers in the Fraser River drainage (British Columbia, Canada) in the early 1900s were thought to have led to complete loss of anadromous sockeye salmon from both rivers. For both reservoirs, recent water release programs resulted in the unexpected downstream migration of juvenile sockeye salmon and the subsequent upstream migration of adults towards the reservoir 2 years later. Here we investigate the evolutionary impact of dams on the sockeye salmon migration behavior by investigating the genetic distinction between migratory and non-migratory individuals within the Alouette and Coquitlam reservoirs. We also compare historical and contemporary genetic connectivity among 11 Lower Fraser River sockeye sites to infer recent population connectivity changes that might have been influenced by anthropogenic activities. Our molecular genetic analyses show a genetic distinction between the sea-run and resident individuals from the Coquitlam reservoir and population splitting time estimates suggest a very recent divergence between them. These results indicate a genetic component to migration behavior. For our broader survey from 11 sites, our comparisons suggest a general decline in gene flow, with a few interesting exceptions. In summary, our results suggest (i) early stage divergence between life history forms of sockeye salmon within one reservoir, and (ii) recent changes in genetic connectivity among Lower Fraser River populations; both of these results have potential recovery implications for historically migratory populations that were affected by anthropogenic barriers such as hydroelectric dams.

In the fish family Poeciliidae, male genitalia, the gonopodia, are remarkably diverse across species; however, we still do not have a good understanding of the evolutionary processes promoting this diversity. For one trait, gonopodium length, several studies support a role for sexual conflict in selection for longer gonopodia. However, genital elongation may come at a cost of reduced locomotor abilities (e.g. resulting from greater drag and resistance). In this study, we were interested in the potential role of natural selection on the evolution of gonopodium length in poeciliids. Specifically, we asked whether a greater genital length impedes male reproductive behaviours at higher flow rates in the Trinidadian guppy, Poecilia reticulata. Using a flow chamber, males were placed with females in low- and high-flow regimes and reproductive behaviours were measured. We did not find evidence for a cost of bearing a longer gonopodium at high flow. However, males did alter their mating tactics in response to current flow. We discuss the implications of our findings, in the light of habitat selection, on the forms of selection operating on gonopodium length and the mating interactions between the sexes in poeciliids.

Accurate understanding of population connectivity is important to conservation because dispersal can play an important role in population dynamics, microevolution, and assessments of extirpation risk and population rescue. Genetic methods are increasingly used to infer population connectivity because advances in technology have made them more advantageous (e.g., cost effective) relative to ecological methods. Given the reductions in wildlife population connectivity since the Industrial Revolution and more recent drastic reductions from habitat loss, it is important to know the accuracy of and biases in genetic connectivity estimators when connectivity has declined recently. Using simulated data, we investigated the accuracy and bias of 2 common estimators of migration (movement of individuals among populations) rate. We focused on the timing of the connectivity change and the magnitude of that change on the estimates of migration by using a coalescent-based method (Migrate-n) and a disequilibrium-based method (BayesAss). Contrary to expectations, when historically high connectivity had declined recently: (i) both methods over-estimated recent migration rates; (ii) the coalescent-based method (Migrate-n) provided better estimates of recent migration rate than the disequilibrium-based method (BayesAss); (iii) the coalescent-based method did not accurately reflect long-term genetic connectivity. Overall, our results highlight the problems with comparing coalescent and disequilibrium estimates to make inferences about the effects of recent landscape change on genetic connectivity among populations. We found that contrasting these 2 estimates to make inferences about genetic-connectivity changes over time could lead to inaccurate conclusions.

Exploratory behavior—an individual’s response to novel environments, resources, or objects—should vary with the associated benefits, including new sources of food and reduced levels of competition, and the costs, such as predation pressure. Using guppies from multiple streams and rivers in Trinidad, we compared guppies from high- and low-predation populations. We found that wild-caught male and female guppies from low-predation populations were more exploratory than high-predation fish when tested in the field and in controlled laboratory conditions. We did not detect significant evidence for a genetic basis for differences in the behavior of high- and low-predation fish using a common-garden approach, but further study is required before conclusions can be made about the relative contribution of genes to population differences in exploratory behavior of guppies. Theory has assumed that predation risk is a cost that will select against high levels of exploratory behavior; this study is one of the few that has tested this assumption, and we show that exploratory behavior is indeed suppressed in guppies from high-predation localities. Exploratory behavior is a component of an individual’s responses to novel environments, resources, and objects (including potential predators) and thus can affect important decisions of animals in the wild (e.g., whether to sample new, potential sources of food, whether to disperse). We compared exploratory behavior of wild-caught guppies from sites with large, dangerous predators with those from sites with small predators that are only a threat to small individuals. Guppies co-occurring with large predators were less exploratory than those from sites with small predators. Factors contributing to this difference could include exposure to predators directly and to conspecifics’ responses to predators. Studies on general behavioral traits (e.g., temperament) combined with knowledge of animals’ environment and evolution are expanding our ability to test ideas about the origin and maintenance of intra-specific variation in fascinating and complex traits.

Kin recognition plays a key role in inbreeding avoidance for taxa from all major animal groups; however, perplexingly, a number of species, for which the risks and costs of inbreeding are high, do not discriminate against relatives in mate choice experiments. We tested a possible explanation for this paradox: most tests of inbreeding avoidance have used virgin females, but theory predicts that virgin females should first mate indiscriminately to gain reproductive assurance and, only subsequently, become choosy. To test this idea, we used the Trinidadian guppy, which suffers inbreeding depression but for which evidence for kin recognition is equivocal. We manipulated rearing environment to disentangle 2 forms of kin recognition and tested the preferences of both virgin and nonvirgin females. As predicted, virgins were indiscriminate in their mate choice. Nonvirgins, in contrast, expressed strong preferences for unfamiliar and unrelated males. Therefore, female guppies recognize kin in a mate choice context but become selective only once reproductively assured. This dynamic likely increases population fitness in newly colonized or small, at-risk populations by ensuring that virgins mate even when only unfamiliar or unrelated males are available. Our findings suggest that inbreeding avoidance may be more common than previously thought and that the use of virgin females can sometimes prevent the detection of powerful mate preferences.

Placentae show considerable diversity in a number of nonmammalian, viviparous organisms, including amphibians, reptilian sauropsids, teleost fish, and chondrichthyes. However, the evolutionary processes driving the evolution of placenta are still debated. In teleost fishes, the genus Poeciliopsis (Poeciliidae) offers a rare opportunity for studying placental evolution: extensive placentation has evolved three independent times within the last 750,000 years and there is substantial interspecific variation in the degree of embryonic, maternal nutrient provisioning and development of the placenta. In poeciliids, the placenta is composed of a hypertrophied maternal follicular epithelium apposed to a highly vascularized embryonic pericardial sac. To better understand placental evolution, we have undertaken a comprehensive comparative study of the maternal follicle in eight closely related Poeciliopsis species that span the range in postfertilization, embryonic, maternal nutrient provisioning (from lecithotrophs, to moderate matrotrophs, to extensive matrotrophs). Using light and scanning electron microscopy, we found that the species that provide extensive postfertilization maternal nutrient provisioning (extensive matrotrophs) have thicker follicles and more extensive folding of the follicular epithelium compared to the lecithotrophs and moderate matrotrophs. Follicle sections and histology revealed that epithelial folds of the extensive matrotrophs are comprised primarily of cuboidal and columnar cells and are richly supplied with capillaries. Among the extensive matrotrophs, enhancements of follicle traits corresponded with increases in the level of maternal nutrient provisioning. Hypertrophied maternal follicles with richly vascularized folds can serve to increase the surface area and, thus, facilitate the transfer of substances between the mother and developing embryo. Finally, we found egg envelopes in the lecithotrophs and moderate matrotrophs, but not in the extensive matrotrophs. Morphological studies, like this one, can provide a better understanding of the natural variation in the structure and functioning of maternal and offspring traits associated with matrotrophy and, thus, insights into the processes driving placental evolution. J. Morphol. 276:707-720, 2015. © 2015 Wiley Periodicals, Inc.

The Trinidadian pike cichlid (Crenicichla frenata) is a major predator of the guppy (Poecilia reticulata), a model system for visual ecology research, and visual predation by the pike cichlid is known to select for male guppies with reduced short-wavelength reflectance. However, an early study of the pike cichlid's visual system suggested a lack of short-wavelength-sensitive cone photoreceptors, a surprising finding as many African cichlids have highly developed short-wavelength vision. In this study, we found evidence for only four expressed cone opsins (LWS, RH2a, SWS2a, and SWS2b), plus one pseudogene (RH2b). Taken together with our microspectrophotometry data, which revealed the presence of three types of cone photoreceptor, including one sensitive to short-wavelength light, this would indicate a broader spectral capacity than previously believed from earlier visual studies of this fish. Relative to the highly diverse African cichlids, however, this Neotropical cichlid appears to have a greatly reduced opsin complement, reflecting both gene loss along the Neotropical lineage (lacking functional RH2b and, possibly, SWS1 opsins) and gene duplication within the African clade (which possesses paralogous RH2aα and RH2aβ opsins). Molecular evolutionary analyses show that positive selection has shaped the SWS2b and RH1 opsins along the Neotropical lineage, which may be indicative of adaptive evolution to alter nonspectral aspects of opsin biology. These results represent the first molecular evolutionary study of visual pigments in a Neotropical cichlid and thus provide a foundation for further study of a morphologically and ecologically diverse clade that has been understudied with respect to the link between visual ecology and diversification.

Sensory bias, a predisposition towards certain signals, has been implicated in the origin of mate preferences in some species. A risk associated with these biases is that they can be co-opted by predators as sensory lures. Here we propose that the orange spots on the brown pincers of a diurnal, predatory species of prawn function as lures for Trinidadian guppies, which have a sensory bias for orange. We exposed female guppies to (i) a life-like model of this Trinidadian prawn with orange, green or no spots on the pincers or (ii) a live, novel (non-Trinidadian) crustacean (crayfish), also with spotted pincers. First, we provide evidence that guppies sympatric with the prawn recognized our model as a potential predator. Next, we found that guppies spent more time in the dangerous head region of the model prawn with orange-spotted pincers compared with unspotted pincers. Finally, we show that allopatric, but not sympatric, guppies spent more time in the vicinity of the head of a live crayfish when orange spots were added to its pincers than when brown spots were added. Our results suggest that the orange spots on prawn pincers can act as a sensory lure.

In prior research, we found the way guppy life histories evolve in response to living in environments with a high or low risk of predation is consistent with life-history theory that assumes no density dependence. We later found that guppies from high-predation environments experience higher mortality rates than those from low-predation environments, but the increased risk was evenly distributed across all age/size classes. Life-history theory that assumes density-independent population growth predicts that life histories will not evolve under such circumstances, yet we have shown with field introduction experiments that they do evolve. However, theory that incorporates density regulation predicts this pattern of mortality can result in the patterns of life-history evolution we had observed. Here we report on density manipulation experiments performed in populations of guppies from low-predation environments to ask whether natural populations normally experience density regulation and, if so, to characterize the short-term demographic changes that underlie density regulation. Our experiments reveal that these populations are density regulated. Decreased density resulted in higher juvenile growth, decreased juvenile mortality rates, and increased reproductive investment by adult females. Increased density causes reduced offspring size, decreased fat storage by adult females, and increased adult mortality.

Data sourcesMedline, Scopus and the Web of Science.Study selectionStudies conducted in children under 16 undergoing general anaesthesia having change in oral health-related quality of life were considered. Selection was undertaken by two reviewers independently.Data extraction and synthesisData abstraction was undertaken independently by three groups of two reviewers - discrepancies were resolved by discussion. Study quality was assessed using the Quality Assessment Tool for Studies of Diverse Design (QATSDD).ResultsTwenty studies were included; there were 18 prospective studies, one randomised trial and one secondary analysis study. Most studies used a pre-test-post-test design and all but one used proxy measures of oral health-related quality of life (OHRQoL). All of the studies reported improved OHRQoL overall. However, results suggested that some aspects of OHRQoL may worsen.ConclusionsHeterogeneity of included papers limited the conclusions which could be drawn. Treatment under GA appears to result in overall improvements in proxy-reported OHRQoL; however, there is a need for further high-quality studies employing validated, child-reported measures of OHRQoL.

In Trinidad, guppies (Poecilia reticulata) in high-predation localities show more cohesive shoaling behaviour than those living with less dangerous predators in low-predation sites. We evaluated the relative contributions of population origin (i.e. genetic and/or maternal effects) and social environment on the expression of shoaling by assessing the behaviour of juveniles reared in a range of social conditions. Focal individuals, offspring of guppies from populations from high- or low-predation localities, were reared in a multifactorial experiment; we created four different social conditions by manipulating the source and demography of the conspecific residents with whom focal individuals interacted. We found that high-predation fish displayed a stronger propensity to shoal than low-predation ones. Our results also suggest a role for interactions between the source of the focal individuals, the demography of the group in which they were reared and the origin of the guppies with whom they were reared. Depending on their origin (high- vs. low- predation) and rearing density, our focal fish were more likely to shoal if they were reared with high-predation residents. Learning from high-predation residents, aggressive interactions with low-predation residents and/or phenotype matching could have played a role in driving this effect of social environment. This effect of the phenotype of conspecifics on shoaling development would enhance heritable differences in shoaling propensity such that both could contribute to the well-documented difference in shoaling behaviour of high- and low-predation guppies in natural populations.

Maintenance of genetic variation in the face of strong natural selection is a long-standing problem in evolutionary biology. One of the most extreme examples of within-population variation is the polymorphic, genetically determined color pattern of male Trinidad guppies (Poecilia reticulata). Female mating preference for rare or novel patterns has been implicated as a factor in maintaining this variation. The origin of this preference is not understood, although inbreeding avoidance has been proposed as a mechanism. Inbreeding avoidance is advantageous when populations exhibit inbreeding depression and the opportunity for mating between relatives exists. To determine whether these conditions are met in a natural guppy population, we assessed mating and reproductive patterns using polymorphic molecular markers. Females produced more offspring with less-related males than with more-related ones. In addition, females were more likely to have mated with lessrelated males, but this trend was only marginally significant. Male heterozygosity was positively correlated with mating success and with the number of offspring sired, consistent with strong inbreeding depression for adult male fitness. These results provide substantial insight into mating patterns of a wild guppy population: strong inbreeding depression occurs, and individuals tend to avoid mating with relatives.

A widely held view is that the strength and form of natural selection varies in time and space in response to varying ecological forces; however, adequate quantitative evaluations of this are relatively scarce. In this study, we measured the strength and form of sexual selection acting on a suite of male morphological traits in a wild ambush bug (Phymata americana) population at 10 sampling dates over 2 years. We tested the prediction that the strength and direction of sexual selection would be associated with one or more important ecological variables. We found that patterns of multivariate selection varied considerably over time, and even within a season. Yet, for this population, a sexually dimorphic color pattern trait was consistently a target of directional selection. The strength of sexual selection on this trait was related to both sex ratio and density, which is consistent with the idea that ecological factors can play an important role in generating patterns of sexual selection. We also demonstrate that the median strength of linear selection obtained from replicated cross-sectional methods was qualitatively similar to the estimates obtained from longitudinal methods, providing multiple lines of evidence that the evolution of sexual color dimorphism in this species is attributable to sexual selection.

Female zebrafish housed in aquaria with spatial complexity (plastic plants) over a 13–16-week period showed reduced levels of aggressive behavior compared to females in bare tanks. In tanks with plants, there was no relationship between levels of aggression and fecundity but, in bare tanks, females experiencing the highest levels of aggression showed reduced fecundity. Our results suggest that it may be beneficial, when maintaining zebrafish at moderate to high densities or working with especially aggressive strains, to house them in spatially complex conditions.

Fruit consumption by birds is an important ecological interaction that contributes to seed dispersal in tropical rainforests. In this field experiment, we asked whether moderate human disturbance alters patterns of avian frugivory: we measured fruit removal by birds in the lower montane rainforest of Tobago, West Indies, using artificial infructescences made with natural fruits from two common woody plants of the forest understory (Psycbotria spp., Rubiaceae). Displays were mounted simultaneously in three forest habitats chosen to represent a gradient of increasing habitat disturbance (primary, intermediate and disturbed), caused by subsistence land use adjacent to a protected forest reserve. We measured the numbers of fruits removed and the effect of fruit position on the likelihood of removal, along with the abundances of all fruits and fruit-eating birds at the study sites. Fruit removal was highly variable and there was not a significant difference in removal rate among forest habitats; however, the trend was for higher rates of removal from displays in primary forest. Canopy cover, natural fruit availability, and frugivore abundance were not good predictors of fruit removal. Birds preferred more accessible fruits (those proximal to the perch) in all habitats, but in disturbed forest, there was a tendency for distal fruits to be chosen more frequently than in the other forest types. One possible explanation for this pattern is that birds in disturbed forests were larger than those in other habitats, and hence were better able to reach the distal fruits. Coupled with differences in bird community composition among the forest types, this suggests that different suites of birds were removing fruit in primary versus disturbed forest. As frugivore species have different effectiveness as seed dispersers, the among-habitat differences in fruit removal patterns that we observed could have important implications for plant species experiencing disturbance; these possible implications include altered amounts of seed deposition and seedling recruitment in Tobago's tropical rainforest.

Given a trade-off between offspring size and number and an advantage to large size in competition, theory predicts that the offspring size that maximizes maternal fitness will vary with the level of competition that offspring experience. Where the strength of competition varies, selection should favor females that can adjust their offspring size to match the offspring's expected competitive environment. We looked for such phenotypically plastic maternal effects in the least killifish, Heterandria formosa, a livebearing, matrotrophic species. Long-term field observations on this species have revealed that some populations experience relatively constant, low densities, whereas other populations experience more variable, higher densities. We compared sizes of offspring born to females exposed during brood development to either low or high experimental densities, keeping the per capita food ration constant. We examined plastic responses to density for females from one population that experiences high and variable densities and another that experiences low and less-variable densities. We found that, as predicted, female H. formosa produced larger offspring at the higher density. Unexpectedly, we found similar patterns of plasticity in response to density for females from both populations, suggesting that this response is evolutionarily conserved in this species.

Animals bred for captivity often have smaller brains and behave differently than their wild counterparts. These differences in brain size have been attributed to genetic changes resulting from, for example, inbreeding depression and pleiotropic effects of artificial selection for traits such as docility. A critical question, though, is whether these differences in brain size are due to plastic responses to the environment, not just genetic changes. We observed a large reduction in brain size in first generation, lab-reared female guppies compared with wild-caught ones (19% smaller telencephalon, 17% smaller optic tectum). We then reared first-generation, lab-born guppies in environments varying in spatial complexity and size in an attempt to isolate factors that might increase brain size and change temperament, but no significant differences in phenotype were observed. The results of these experiments show that, although the environmental factors responsible for the effect have not been found, even first generation lab-reared individuals can have smaller brains than wild individuals.

Color patterns in fish are often multicomponent signals, composed of pigment-based and structural color patches that can be used to communicate within species, in both inter- and intrasexual interactions, and between species. In this review, we discuss some of the roles played by pigment-based elements of color pattern. We begin by discussing general forms of coloration, classifying them by appearance (e.g., cryptic vs. conspicuous) and apparent function (e.g., conspicuous coloration and mating displays, stripes and cooperation, and bars and aggression). We then briefly discuss the roles pigments play in the perception of these color patterns via their presence in the eye. In the last section, we look at the relative importance of carotenoid versus melanic coloration in situations where honest signals to potential rivals and potential mates might be required. In this survey, we have highlighted some recent research, especially studies that consider both the physiological and behavioral processes underlying the evolution and expression of pigment-based color patterns in fish. The nature of pigmented color patterns depends not just on the dynamics of pattern development and physiological regulation, but also on the behavioral roles played by these patterns, both now and in the past. As such, advances in particular fields of study on pigment patterns (physiology, developmental biology, behavioral ecology, evolutionary biology, etc.) will increasingly depend on insights from other fields.

The ability to return to, or avoid, specific locations is often critical to fitness-related activities. We tested for differences in spatial memory of guppies, Poecilia reticulata, from low- and high-predation populations in a maze task. We also measured the time each fish took to make a decision in the maze, because individuals can show a trade-off between the speed and the accuracy of their decisions during this kind of task. Because brain size can affect cognitive performance, we also measured brain size. There were no differences in the number of errors made or time to find the reward between predation regimes. However, high-predation guppies tended to take longer to make the decision about which maze chamber to enter than low-predation guppies; thus, low-predation guppies were more willing to make quick and potentially inaccurate decisions, a strategy we have termed ‘hastiness’. Individuals within populations also varied in hastiness and we found that hasty guppies tended to have smaller telencephalons, the brain region most responsible for spatial memory. There was no difference in brain size in relation to predation regime, although lab-reared fish had smaller brains than wild-caught fish. This study shows that the careful observation of an animal's strategy for solving spatial problems may reveal subtle differences that are associated with ecology and brain size.

Sexual selection is a potent evolutionary force often invoked to explain observed cases of sexual dimorphism. However, evidence of this process operating on existing phenotypic variation is limited. We investigated whether sexual selection could account for sexual dimorphism in size and color pattern in the ambush bug Phymata americana. We considered the alternative hypothesis that dimorphism merely reflects sex differences in habitat use but found no evidence of sex differences in microhabitat during 2 sampling periods in the wild. Although the form of sexual (phenotypic) selection on male lateral color pattern varied between samples, selection consistently favored lateral coloration in males but not size. For females, weight was a consistent predictor of mating status in both the early and the late season. We performed 2 separate laboratory studies to investigate potential proximate mechanisms of sexual selection that might account for the field data. Although we found that male weight predicted male success in direct male‐male competition and male courtship intensity predicted success in male‐female interactions, we did not detect any role of male color pattern in either laboratory study. These data suggest that visual signaling is unlikely to play a role in the evolution of color pattern dimorphism in this species. Consistent with the field data, our laboratory results also found that female weight predicted the probability of copulation, possibly indicating that female receptivity coincides with female reproductive cycle (i.e., egg maturation). Key words: color pattern, phenotypic selection, sexual dimorphism, sexual selection. [Behav Ecol]