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Understanding variation in social organization that lacks a strong phylogenetic signal represents a key focus of research in behavioural ecology. Accordingly, we established a framework that identifies whether a range of ecological and social factors are affecting the social maintenance of taxa across multiple categories of social variation (ranging from large to fine‐scale): 1) forms of sociality, 2) degree of sociality, 3) social plasticity and 4) hierarchy maintenance. Each category of variation can then be assessed in combination to provide an outlook for social maintenance in light of predictor factors. We modelled this framework by quantifying each category over time, space and disturbance regime using multiple species of coral‐dwelling gobies, genus Gobiodon. Gobies are an interesting model system as they vary in social structure, have within‐group cooperation, and form mutualisms with coral hosts, which are vulnerable to climatic disturbances. We found that gobies varied in forms of sociality – from being more solitary or pair‐forming in high disturbance regimes, versus group‐forming in moderate disturbance regimes at some locations. Only low or moderate degrees of sociality were observed in gobies, with location or disturbance regime affecting some species. The size of coral hosts influenced the social plasticity of gobies, which was affected by climatic disturbances. Gobies did not exhibit direct changes to hierarchy maintenance, as location and disturbance regime did not affect their size‐based hierarchies. Lastly, by combining the four categories of variation, we found a high loss of sociality in coral‐dwelling gobies due to environmental disturbances, which likely affects overall goby survival as group‐forming can improve survival and fitness. By using our structured framework, we identified which categories of social variation were influenced by ecological factors like location and disturbance. This framework therefore provides an excellent tool for predicting future responses of animal societies to environmental stressors. [ABSTRACT FROM AUTHOR]

Simple Summary: Freshwater crayfish play critical roles in their ecosystems; however, non-native species are increasingly threatening native crayfish populations worldwide. Here, we review the literature examining or documenting the impacts of invasive freshwater crayfish and other non-native species on native freshwater crayfish. Four key mechanisms through which invasive crayfish impact native crayfish were identified: competition, predation, introduction of disease, and reproductive impacts, while other non-native species primarily impact native crayfish through predation. We highlight a need for more field-based investigations examining competitive interactions between invasive and native crayfish and identify a deficit of monitoring efforts for many non-native species that are likely to substantially impact native crayfish populations. Overall, the findings underscore the profound and diverse threats posed by non-native species to native crayfish, necessitating further research to safeguard native crayfish populations. Freshwater crayfish are vital species in ecosystems where they naturally occur, as they hold keystone and ecological engineering positions in these systems. Non-native species are common and widely spread throughout Earth's freshwater ecosystems and can have severe impacts on native crayfish populations. There has yet to be a comprehensive global review of the impacts of non-native species on native crayfish. Two literature searches were conducted using Web of Science and Google Scholar to find articles to address four key aims: (1) summarise trends in the literature; (2) examine the mechanisms by which invasive crayfish impact native crayfish species; (3) examine the mechanisms by which other non-native species, such as fish, impact native crayfish species; and (4) identify gaps in knowledge and research priorities. This review highlights that a far greater amount of research has addressed the effects of invasive crayfish than other non-native species. The research on invasive crayfish focuses on four types of interactions with native crayfish: competition, predation, introduction of disease, and reproductive impacts. Studies addressing the impacts of other non-native species on crayfish indicate that predation and habitat destruction by these species are the key processes impacting native crayfish. It is evident that field-based research, particularly concerning competition between invasive and native crayfish, is limited. Therefore, further in situ research is needed to assess the validity of laboratory results in a natural setting. Additionally, in many cases, the impact of certain non-native species on native crayfish populations has gone unmonitored. For this reason, it is recommended that additional research focus on assessing the impact of these non-native species. To conclude, the impacts of invasive crayfish on native crayfish are profound and wide-ranging, often leading to population decline or extirpation. Further, other non-native species are also likely to have a highly deleterious impact on native crayfish populations; however, more research is required to understand the scope of this impact. [ABSTRACT FROM AUTHOR]

From a conservation standpoint, species that are managed without consideration of their population sizes and connectivity have the potential to be over‐exploited and/or incur population decline. The burrowing shrimp, Trypaea australiensis, is an important ecosystem engineer and fishery resource caught in large numbers for which population information is unknown for properly managing the species. Here, we determined the level of population structure of T. australiensis across three locations along the East Coast of New South Wales, Australia, using genome‐wide single nucleotide polymorphisms (SNPs) obtained through double digest Restriction‐site Associated DNA‐sequencing (ddRAD‐seq). Analysis of population structure, including pairwise Fst (−0.003 to −0.001), STRUCTURE (K = 2) and Discriminant Analysis of Principal Components (DAPC) showed no evidence of structure among locations. Our findings provide crucial preliminary population genetic data for a key cryptic species, that also suggests gene flow among sampling locations enables the management of fisheries throughout the study area as a single unit. [ABSTRACT FROM AUTHOR]

Establishing the activity, movement and habitat‐use patterns of endangered species is fundamental in designing effective conservation plans. In Australia, the critically endangered freshwater crayfish, Euastacus dharawalus, is facing considerable risk of extinction due to numerous stressors, including the proliferation of the invasive Cherax destructor throughout their range. However, little is known about the fine‐scale spatial ecology of E. dharawalus and if this overlaps with C. destructor. Here, we aimed to establish the activity, movement and habitat‐use patterns of E. dharawalus as well as conduct a preliminary assessment into the overlap of their spatial ecology with that of C. destructor. In 2020, 15 E. dharawalus and six C. destructor were radio tracked at a site along Wildes Meadow Creek in the Southern Highlands region of New South Wales, Australia. Additionally, in 2021, 12 more E. dharawalus were tracked at this site over the same period. Euastacus dharawalus exhibited high site fidelity, small home ranges and diurnal activity patterns. Both E. dharawalus and C. destructor indicated significant preference for bank habitat, indicating potential for individual competitive interactions. We also report a significant reduction in the movement and activity of E. dharawalus from 2020 to 2021, possibly in response to population control of C. destructor or environmental variation across the 2 years. Our results indicate that the preservation or restoration of bank habitat will be critical to the conservation of E. dharawalus. Further, due to the extent of habitat‐use overlap between E. dharawalus and C. destructor, we conclude that C. destructor represents a substantial competitive threat to E. dharawalus, and therefore, C. destructor population control efforts should continue within the range of E. dharawalus. [ABSTRACT FROM AUTHOR]

Many animals use color to signal their quality and/or behavioral motivations. Colorful signals have been well studied in the contexts of competition and mate choice; however, the role of these signals in nonsexual, affiliative relationships is not as well understood. Here, we used wild social groups of the cichlid fish Neolamprologus pulcher to investigate whether the size of a brightly colored facial patch was related to 1) individual quality, 2) social dominance, and/or 3) affiliative relationships. Individuals with larger patches spent more time foraging and tended to perform more aggressive acts against conspecific territory intruders. We did not find any evidence that the size of these yellow patches was related to social rank or body size, but dominant males tended to have larger patches than dominant females. Additionally, patch size had a rank-specific relationship with the number of affiliative interactions that individuals engaged in. Dominant males with large patches received fewer affiliative acts from their groupmates compared to dominant males with small patches. However, subordinates with large patches tended to receive more affiliative acts from their groupmates while performing fewer affiliative acts themselves. Taken together, our results suggest that patch size reflects interindividual variation in foraging effort in this cichlid fish and offer some of the first evidence that colorful signals may shape affiliative relationships within wild social groups. [ABSTRACT FROM AUTHOR]

Context: Trophic overlap between invasive and native species can cause a competitive displacement of the native. In Australian freshwaters, the invasive crayfish Cherax destructor has proliferated into the ranges of native Euastacus species. Aims: To examine trophic overlap between C. destructor and the critically endangered Euastacus dharawalus and determine whether C. destructor population control causes shifts in the diet and trophic position of E. dharawalus. Methods: We compared δ13C and δ15N values of tissue from both species collected from two sites. Population control of C. destructor was then conducted at one site, whereas the C. destructor population remained uncontrolled at the second site. The δ13C and δ15N values of E. dharawalus were then once again assessed. Key results: Both species occupied similar trophic positions and consumed similar proportions of each food resource prior to control efforts. However, we found increases in the contribution of detritus to the diet of E. dharawalus following the removal of C. destructor , whereas no dietary shifts occurred at the uncontrolled site. Conclusions and implications: The increase in detrital consumption suggests that control of C. destructor increased the availability of a preferred resource. Further, dietary competition between C. destructor and E. dharawalus is likely and reinforces C. destructor representing a substantial threat to Euastacus crayfish. The invasive common yabby has proliferated extensively throughout Australian freshwaters and is likely to compete against native freshwater crayfish over food resources. We assessed whether the fish down of a common yabby population would alter the diet of a critically endangered native spiny crayfish. We found substantial shifts in the diet of the native crayfish following the control of the common yabby population. [ABSTRACT FROM AUTHOR]

Marine organisms, particularly invertebrates, are relatively understudied regarding social structure and behaviour, especially those that are cryptic. While empirically challenging to investigate, these species can provide novel insights into the evolution of sociality given their unique ecology. Our aim was to quantify in-situ the social structure and its underlying correlates in the Australian burrowing shrimp, Trypaea australiensis Dana, 1852 (Callianassidae). We show that T. australiensis exhibits intraspecific variation in social structure, being most often found in solitary arrangements, frequently in pairs (including homosexual and heterosexual arrangements), and sometimes in groups. The majority of shrimp in pairs and groups were found in heterosexual pairings or groups of one male and multiple females. Variation in social structure was correlated with variation in body size characteristics, seasonality, and site. These findings demonstrate that a wider array of social structures are exhibited by this species than previously expected, but the obvious limitations associated with sampling a cryptic burrowing species in situ mean that further investigations under controlled conditions, including laboratory behavioural manipulations, will be needed to confirm the current findings. The use of resin casts to understand burrow morphology would be important for understanding the causes of intraspecific variation in this and other cryptic species. [ABSTRACT FROM AUTHOR]

Mutualisms are prevalent in many ecosystems, yet little is known about how symbioses are affected by ecological pressures. Here, we show delayed recovery for 13 coral‐dwelling goby fishes (genus Gobiodon) compared with their host Acropora corals following four consecutive cyclones and heatwaves. While corals became twice as abundant in 3 years postdisturbances, gobies were only half as abundant relative to predisturbances and half of the goby species disappeared. Although gobies primarily occupied one coral species in greater abundance predisturbances, surviving goby species shifted hosts to newly abundant coral species when their previously occupied hosts became rare postdisturbances. As host specialization is key for goby fitness, shifting hosts may have negative fitness consequences for gobies and corals alike and affect their survival in response to environmental changes. Our study is an early sign that mutualistic partners may not recover similarly from multiple disturbances, and that goby host plasticity, while potentially detrimental, may be the only possibility for early recovery. [ABSTRACT FROM AUTHOR]

Simple Summary: Aggressive invasive species can outcompete native species in contests over resources, which can lead to the exclusion of a native species by the invader. Invasive freshwater crayfish are often more aggressive than their native counterparts, however contests between invasive and native crayfish are typically investigated under laboratory conditions and are rarely examined in a natural setting. We used a baited underwater camera in a stream located in New South Wales, Australia to examine behavioural interactions between an invasive crayfish and a critically endangered native crayfish to determine which species was dominant. We found the native species dominant over the invader when larger, however when the species were size-matched the dominance of the native was lost and neither species exhibited a significant pattern of dominance. This outcome indicates the invasive crayfish represents a threat to the native since it may be able to outcompete the native over resources. Further, this outcome contrasts to previous laboratory findings, highlighting the importance of field observations in establishing the extent of impact an invader may be having on a native species. Competitive behavioural interactions between invasive and native freshwater crayfish are recognised as a key underlying mechanism behind the displacement of natives by invaders. However, in situ investigations into behavioural interactions between invasive and native crayfish are scarce. In Australian freshwater systems, the invasive Cherax destructor has spread into the ranges of many native Euastacus species, including the critically endangered Euastacus dharawalus. Staged contests between the two species in a laboratory setting found E. dharawalus to be the dominant competitor, however, this has yet to be corroborated in situ. Here, we used baited remote underwater video (BRUV) to examine in situ intra- and inter-specific behavioural interactions between E. dharawalus and C. destructor. We sought to evaluate patterns of dominance and differential contest dynamics between the species to provide indications of competition between the two species. We found E. dharawalus to be dominant over C. destructor based on pooled interspecific interaction data and size-grouped interactions where C. destructor was the smaller opponent. Alarmingly, however, when C. destructor was within a 10% size difference the dominance of E. dharawalus was lost, contrasting with the outcomes of the laboratory-staged study. In addition, we report that small C. destructor initiated significantly more contests than larger conspecifics and larger E. dharawalus, a pattern that was not observed in smaller E. dharawalus. Further, intraspecific interactions between C. destructor were significantly longer in duration than intraspecific interactions between E. dharawalus, indicating a willingness to continue fighting. Concerningly, these outcomes point towards inherent and greater aggressiveness in C. destructor relative to E. dharawalus and that only larger E. dharawalus hold a competitive advantage over C. destructor. Therefore, we conclude that C. destructor represents a substantial threat to E. dharawalus through competitive behavioural interactions. Further, due to the disparity between our findings and those produced from laboratory-staged contests, we recommend the use of in situ studies when determining the behavioural impacts of invasive crayfish on natives. [ABSTRACT FROM AUTHOR]

Shoaling behaviour is commonly displayed by fishes and is thought to reduce predation and increase foraging efficiency. Shoaling relies on coordination between individuals, with higher cohesion and alignment among individuals within a shoal providing greater net benefits of this behaviour. Whilst single species often shoal together in conspecific groups, mixed-species shoaling is frequently observed and has been identified as an important determinant of individual fitness for the multiple species involved. Despite their prevalence, the structure of mixed-species shoals and the mechanisms by which individuals gain protection from predators and enhance their foraging efficiency are not as well understood as for single-species shoals. In fact, mixed-species shoals may be less coordinated than single-species shoals, raising the intriguing question of why fishes form mixed-species shoals when this behaviour could be less beneficial than single-species shoaling. Here we used in situ stereo-video techniques to compare within and between shoal differences in cohesion and alignment, for mixed- and single-species shoals containing the tropical vagrant Indo pacific sergeant major damselfish, Abudefduf vaigiensis, in temperate waters. As expected, mixed-species shoals were less aligned than single-species shoals. However, within mixed-species shoals conspecifics were more cohesive and aligned than were heterospecifics, suggesting coordinated single-species subgroups formed within larger mixed-species shoals. The formation of subgroups may mitigate costs associated with differences between species, therefore enhancing benefits of mixed-species shoaling. As such, multiple levels of social structure may exist within mixed-species shoals that could facilitate growth and survival for vagrant A. vaigiensis in temperate regions. More broadly, this research highlights the importance of considering detailed internal structures of mixed-species shoals when trying to understand cost–benefit trade-offs experienced by individuals. [ABSTRACT FROM AUTHOR]

Aggressive encounters between invasive and native species are considered a key threat associated with the spread of invasive species. Extrinsic factors such as habitat complexity can profoundly influence the outcome of aggressive interactions between conspecifics, and this may also be the case in invasive‐native species interactions. This study used invasive and native freshwater crayfish species in Australia as a model system to investigate the influence of habitat complexity on aggression in both intraspecific and interspecific contests. Paired contests between the native Euastacus spinifer and the invasive Cherax destructor were conducted in the laboratory under high and low habitat complexity conditions. Furthermore, the influence of prior residency was examined, with one individual assigned the resident and the other as the intruder. In intraspecific contests, the number of interactions and aggression score were significantly reduced under high complexity conditions; however, complexity had no effect on the time spent interacting and contest outcome. Instead, the two crayfish species differed in terms of time spent interacting. In interspecific contests, complexity had no effect on any of the aggression metrics. Alarmingly, however, we demonstrate that when C. destructor was a resident the likelihood that E. spinifer won a contest fell to a mere 8% compared to 31% when E. spinifer was resident. This study suggests that while habitat complexity plays a role in shaping aggressive behaviour in intraspecific interactions, invasive species are competitively dominant if they are already established i.e. resident in a location and even as intruders. Therefore, preserving habitat complexity in freshwater systems may not be sufficient to sustain populations of native species, and other measures that mitigate the potential for range overlap between the species would also be needed to prevent the further spread of invasive species such as C. destructor within freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Animals are faced with a fundamental risk-reward trade-off when making decisions about foraging in the presence of predation, yet little is known about how social, reproductive and environmental factors mediate this trade-off. In the marine environment, anemonefishes provide a model system for investigating the determinants of risk–reward trade-offs, because they live in size- and sex-structured groups within protective sea anemones tentacles, yet feed predominantly in the water column where they are at risk of predation. Furthermore, exposure to changing tides means the availability of planktonic food covaries with their risk of predation. Therefore, we examined how tide, sex and status, and the presence of eggs influenced the time that Amphiprion mccullochi spent at different distances from their anemone, a proxy for foraging effort and predation risk. We found that individuals significantly adjusted their time spent far and close to the anemone depending on the tide, status and the presence of eggs, and that these adjustments can be explained in light of threat sensitive behaviour. This study illustrates the relative importance of environmental and social factors on intraspecific variation in foraging and antipredator behaviour and bolsters our understanding of the decision's individuals make to balance the costs and benefits of foraging over temporal and spatial scales. [ABSTRACT FROM AUTHOR]

Freshwater crayfish are among the most endangered animal groups in the world. Appropriate management requires an understanding of sampling bias when assessing their distribution and abundance. We evaluated the effectiveness of a variety of sampling methods for detecting freshwater crayfish (genus Euastacus) in situ and potential biases towards individual-level traits associated with these methods. We also experimentally manipulated the presence of crayfish within opera house traps to determine the effects of trap residency on capture rate and the characteristics of crayfish approaching the traps. Baited hoop nets and baited remote underwater video surveys (BRUVS) detected significantly more crayfish than did unbaited video surveys (RUVS). Crayfish captured in baited hoop nets were significantly larger than were crayfish measured in the BRUV and RUV surveys, suggesting that hoop nets were biased to capturing larger animals. The experiment demonstrated that a greater number of crayfish entered empty rather than occupied traps; however, there were no differences in their body sizes. We highlight the importance of optimising sampling for freshwater crayfish to ensure reliable and robust population estimates. This is of critical importance as many have highly restricted ranges and face numerous threats. We contend that this will assist in informing conservation strategies to protect aquatic species at risk. Freshwater crayfish are among the most endangered animal groups in the world. We examined bias associated with baited traps for members of this diverse group in Australia. We confirmed that traps predominantly captured large males, whereas their abundance was underestimated two- to three-fold when compared with that from baited video surveys. Animals avoided traps with a captive crayfish. Video techniques can better inform conservation efforts. [ABSTRACT FROM AUTHOR]

With the onset and increasing frequency of multiple disturbances, the recovery potential of critical ecosystem-building species and their mutual symbionts is threatened. Similar effects to both hosts and their symbionts following disturbances have been assumed. However, we report unequal declines between hosts and symbionts throughout multiple climate-driven disturbances in reef-building Acropora corals and cryptobenthic coral-dwelling Gobiodon gobies. Communities were surveyed before and after consecutive cyclones (2014, 2015) and heatwaves (2016, 2017). After cyclones, coral diameter and goby group size (i.e., the number of gobies within each coral) decreased similarly by 28–30%. After heatwave-induced bleaching, coral diameter decreased substantially (47%) and gobies mostly inhabited corals singly. Despite several coral species persisting after bleaching, all goby species declined, leaving 78% of corals uninhabited. These findings suggest that gobies, which are important mutual symbionts for corals, are unable to cope with consecutive disturbances. This disproportionate decline could lead to ecosystem-level disruptions through loss of key symbiont services to corals. [ABSTRACT FROM AUTHOR]

Animals forming social groups that include breeders and nonbreeders present evolutionary paradoxes; why do breeders tolerate nonbreeders? And why do nonbreeders tolerate their situation? Both paradoxes are often explained with kin selection. Kin selection is, however, assumed to play little or no role in social group formation of marine organisms with dispersive larval phases. Yet, in some marine organisms, recent evidence suggests small‐scale patterns of relatedness, meaning that this assumption must always be tested. Here, we investigated the genetic relatedness of social groups of the emerald coral goby, Paragobiodon xanthosoma. We genotyped 73 individuals from 16 groups in Kimbe Bay, Papua New Guinea, at 20 microsatellite loci and estimated pairwise relatedness among all individuals. We found that estimated pairwise relatedness among individuals within groups was significantly higher than the pairwise relatedness among individuals from the same reef, and pairwise relatedness among individuals from the same reef was significantly higher than the pairwise relatedness among individuals from different reefs. This spatial signature suggests that there may be very limited dispersal in this species. The slightly positive relatedness within groups creates the potential for weak kin selection, which may help to resolve the paradox of why breeders tolerate subordinates in P. xanthosoma. The other paradox, why nonbreeders tolerate their situation, is better explained by alternative hypotheses such as territory inheritance, and ecological and social constraints. We show that even in marine animals with dispersive larval phases, kin selection needs to be considered to explain the evolution of complex social groups. [ABSTRACT FROM AUTHOR]

Grouping behaviour displayed by animals is usually attributed to predation and foraging‐related benefits. The mechanisms of predator protection and foraging efficiency are diverse and often produce conflicting drivers of grouping behaviour. One key conflict is that between group size and phenotypic oddity. Theoretically, individuals should choose the largest available group due to multiple mechanisms associated with "safety in numbers". However, individuals should also choose the most phenotypically similar group members due to the "predator confusion effect". This conflict is particularly important within the context of mixed‐species groups because, while their formation may facilitate large group size, phenotypic differences between species may be costly due to oddity. To investigate the interacting effects of shoal size, composition and predator presence on grouping decisions, choice experiments were conducted using displaced tropical damselfish, Abudefduf vaigiensis, settling in temperate south‐eastern Australia (termed vagrants) as a model species. Contrary to predictions, A. vaigiensis displayed no preference for single‐ over mixed‐species shoals, with or without a predator present. These results suggest that shoal composition may not be an important driver of shoal choice in this system. Further, A. vaigiensis showed no preference for larger mixed‐species shoals over smaller single‐species shoals. These outcomes are discussed within the context of climate change‐driven redistribution of A. vaigiensis in temperate south‐eastern Australia. [ABSTRACT FROM AUTHOR]

Plasticity, the capacity of individuals to respond to changing environments by modifying traits, may be critically important for population persistence by allowing for adaptive responses on shorter timescales than genetic change. Here, we use the clown anemonefish Amphiprion percula, whose access to resources is constrained by their anemones, to test the role of plasticity in generating variation in reproductive success among groups. We surveyed a wild clownfish population and found positive correlations between anemone area, fish size, reproduction and parental care. We used structural equation modeling to test the hypothesis that these correlations emanate from variation in anemone area and found support for a pathway linking anemone area to female investment, female investment to male investment and male investment to embryo survival. Next, we experimentally tested whether plasticity in response to resource availability can result in variation in parental traits using a feeding manipulation and found substantial plasticity in reproduction and parental care in response to changes in the availability of food resources. The results of this study reveal the role of plasticity in response to local resource availability in generating variation among individuals in reproductive strategies, linking studies of behavior and demography in this model species, and ultimately contributing to our ability to predict how populations might cope with environmental changes. [ABSTRACT FROM AUTHOR]

Understanding the determinants and consequences of predation effort, success and prey responses is important since these factors affect the fitness of predators and prey. When predators are also invasive species, the impacts on prey can be particularly far‐reaching with ultimate ecosystem‐level consequences. However, predators are typically viewed as behaviourally fixed within this interaction and it is unclear how variation in predator social dynamics affects predator–prey interactions. Using the invasive eastern mosquitofish Gambusia holbrooki and a native glass shrimp Paratya australiensis in Australia, we investigated how varying levels of social conflict within predator groups influences predator–prey interactions. By experimentally manipulating group stability of G. holbrooki, we show that rates of social conflict were lower in groups with large size differences, but that routine metabolic rates were higher in groups with large size differences. Predation effort and success did not vary depending on group stability, but in stable groups predation effort by aggressive dominants was greater than subordinates. The anti‐predator responses of prey to the stability of predator groups were mixed. While more prey utilized shelters when exposed to stable compared to unstable groups of predators, a greater proportion were sedentary when predator groups were unstable. Overall, this study demonstrates predator group stability is modulated by differences in body size and can influence prey responses. Further, it reveals a hidden metabolic cost of living in stable groups despite reduced overt social conflict. For invasive species management, it is therefore important to consider the behavioural and physiological plasticity of the invasive predators, whose complex social interactions and metabolic demands can modulate patterns of predator–prey interactions. [ABSTRACT FROM AUTHOR]

The formation of mixed‐species social groups, whereby heterospecifics form and maintain either transient or stable groups with each other, can confer substantial fitness benefits to individuals. Such benefits may arise via multiple mechanisms associated with both predation avoidance and foraging efficiency. In fishes, mixed‐species shoaling reportedly occurs where displaced tropical species (known as "vagrants") interact with resident temperate species, although little is known about the nature and frequency of such interactions. To investigate this phenomenon, we used displaced tropical Indo‐pacific Sergeant Abudefduf vaigiensis settling in temperate south‐eastern Australia as a model system. Underwater visual surveys revealed shoal composition and size differed significantly between open‐water and reef habitats, with shoals in open habitats being larger and more speciose. Shoals containing A. vaigiensis were mainly mixed‐species, and larger and more speciose in open habitats than nearer to reef. Since both foraging efficiency (via access to plankton) and predation threat likely increase with increasing distance from reef habitat, we suggest that mixed‐species shoaling mitigates predation risk whilst allowing increased foraging opportunities for A. vaigiensis in open areas. These findings provide support for the importance of mixed‐species shoaling to the persistence of tropical reef fishes in temperate regions. [ABSTRACT FROM AUTHOR]

Under projected levels of ocean acidification, shifts in energetic demands and food availability could interact to effect the growth and development of marine organisms. Changes to individual growth rates could then flow on to influence emergent properties of social groups, particularly in species that form size-based hierarchies. To test the potential interactive effects of (1) food availability, (2) elevated CO2 during juvenile development, and (3) parental experience of elevated CO2 on the growth, condition and size-based hierarchy of juvenile fish, we reared orange clownfish (Amphiprion percula) for 50 days post-hatching in a fully orthogonal design. Development in elevated CO2 reduced standard length and weight of juveniles, by 9% and 11% respectively, compared to ambient. Development under low food availability reduced length and weight of juveniles by 7% and 15% respectively, compared to high food. Parental exposure to elevated CO2 restored the length of juveniles to that of controls, but it did not restore weight, resulting in juveniles from elevated CO2 parents exhibiting 33% lower body condition when reared in elevated CO2. The body size ratios (relative size of a fish from the rank above) within juvenile groups were not affected by any treatment, suggesting relative robustness of group-level structure despite alterations in individual size and condition. This study demonstrates that both food availability and elevated CO2 can influence the physical attributes of juvenile reef fish, but these changes may not disrupt the emergent group structure of this social species, at least amongst juveniles. [ABSTRACT FROM AUTHOR]

Population densities of invasive species fluctuate spatially and temporally, suggesting that the intensity of their aggressive interactions with native species is similarly variable. Although inter‐specific aggression is often thought to increase with population density, it is often theorized that it should be exceeded by intra‐specific aggression since conspecifics share a greater degree of resource overlap. Yet, the magnitude of intra‐specific aggression is seldom considered when examining aggressive interactions, particularly those between invasive and native species. Here, we manipulated the density of the invasive eastern mosquitofish, Gambusia holbrooki, and observed its aggressive interactions with juveniles of the native Australian bass, Macquaria novemaculeata in a laboratory setting. For both species, the magnitudes of intra‐ and inter‐specific aggression were recorded. Regardless of density, the native M. novemaculeata was more aggressive towards heterospecifics than G. holbrooki was. In addition to this, M. novemaculeata was more aggressive to G. holbrooki than towards conspecifics, at both low‐ and high‐density conditions. In contrast, G. holbrooki was similarly aggressive towards M. novemaculeata and G. holbrooki at a high density, yet at low density, displayed significantly more aggression towards conspecifics than M. novemaculeata. These findings demonstrate the importance of considering intra‐specific aggression when exploring behavioural interactions between native and invasive species. [ABSTRACT FROM AUTHOR]

The formation of social groups has important impacts on fitness for many animal species, with differences in group compositions resulting in a range of fitness outcomes for individuals. Recent interest in mixed‐species grouping, which extends from a large body of literature invested in understanding single‐species grouping, highlights novel complexities of group formation which relate to phenotypic, behavioural and physiological differences that naturally exist between species. Among fishes, mixed‐species shoaling is a common form of social grouping behaviour displayed across a range of marine and freshwater ecosystems. Research explaining mixed‐species shoaling shows some overlap with explanations for single‐species shoaling; however, it also demonstrates that distinct differences between species give rise to unique cost‐benefit trade‐offs which need to be incorporated into conceptual models of mixed‐species shoaling behaviour. Unique predation related trade‐offs may arise from inefficiency of the confusion effect, variation in vigilance between species and unequal species‐preferences shown by predators, whilst unique foraging‐related trade‐offs may arise from diet partitioning, variations in foraging behaviour and differences in competitive abilities between species. We review the literature on fitness outcomes associated with mixed‐species shoaling and present a new theoretical framework to explain the cost‐benefit trade‐offs for individuals within mixed‐species shoals. The framework incorporates both trade‐offs arising from differences between species and those arising from group size, the former having been largely ignored due to a focus on single‐species shoaling. Our framework is designed to inform future research striving to explain mixed‐species shoaling behaviour. [ABSTRACT FROM AUTHOR]

Biological invasions are a major cause of biodiversity loss and, coupled with climate change, will likely have detrimental impacts for native species and the functioning of ecosystems. To mitigate such impacts, it is important to elucidate the behavioural mechanisms underpinning interactions between invasive and native species. Here we examined how competitive interactions between invasive and native species are modified under conditions of near-future elevated water temperature using freshwater crayfish as a model system. Contest experiments between the native Euastacus spinifer and invasive Cherax destructor revealed that the competitive advantage of E. spinifer at current maximum temperatures (22 °C) was reversed at elevated near-future temperatures (26 °C), after controlling for relative body size. In addition, the native crayfish spent twice as long motionless at 26 °C than C. destructor, consistent with physiological challenges underpinning this competitive reversal. Most alarmingly, E. spinifer experienced significant mortality after fighting C. destructor, particularly at 26 °C. Mortality usually ensued two days post-contest even when E. spinifer had won. Mortality was rare when fighting conspecifics. Together, these results suggest that while E. spinifer is more likely to win contests under current conditions, it could suffer considerable impacts if climate change and the spread of invasive C. destructor continue unabated. [ABSTRACT FROM AUTHOR]

Aggressive contests amongst conspecifics are important to understand from an ecological and evolutionary perspective as contest dynamics can directly influence individual fitness. For some species, individual attributes such as relative body size closely predict the outcome, intensity and duration of contests, whereas for others, prior social experiences play a key role. However, disentangling the relative effects of individual attributes and social experiences is challenging from an experimental perspective, and because of this, few studies have investigated relative effects of multiple factors. Rockpool fishes have been well studied in terms of factors governing abundance, distribution and community structure, but much less so in terms of contest behaviour. This is surprising because contest dynamics are likely to directly affect the distribution of fishes along the rocky shore, and hence indirectly govern population and community composition. Here, we explored multiple factors potentially influencing contest behaviour in a numerically dominant, resident intertidal fish species, Bathygobius cocosensis (Gobiidae). Using a series of staged pairwise contest trials, we investigated the effect of size, sex and social experiences (namely prior residency and winner–loser experiences) on contest dynamics. We found no evidence that prior residency influenced contest outcome, suggesting social experiences play a minor role in contest dynamics. Previous winner/loser experience also did not influence contest outcome, although this is likely a product of low sample size. In addition, the likelihood of winning was unrelated to contestant sex, and the combination of sexes in paired contests did not influence contest intensity or duration. Instead, body size was related to contest outcome, intensity and duration in the majority of experimental trials. These results suggest that body size rather than sex or social experiences is the key determinant of contest dynamics in this species. We suggest that the dynamic biotic and abiotic environment inhabited by intertidal fish may reduce the influence of prior social experiences in modulating contest dynamics. [ABSTRACT FROM AUTHOR]

The present study investigates how the humbug damselfish Dascyllus aruanus, subject of a large number of ecological, evolutionary and behavioural studies, responds to the presence of human observers (effect of scuba diver presence‐absence) and how the method of data collection (directly by a scuba diver v. indirectly via video camera) may affect the quality of behavioural data. Scuba diver presence had only subtle effects on fish behaviour. The efficiency of the method of scoring fish behaviour depended on the behaviour under consideration: those behaviours that occur in close proximity to the corals were scored more effectively directly by a scuba diver while those that are performed in a more rapid or repetitive fashion were scored more effectively indirectly via video camera. These results provide a foundation for future behavioural research on D. aruanus and other fishes where scuba divers or video cameras are the prevalent means of data collection. [ABSTRACT FROM AUTHOR]

Invasive species are known to competitively displace native species via direct behavioural interactions, or contests, which can result in limited access to valuable resources such as food or shelter for the native. Here, we aimed to determine the dynamics and outcome of agonistic contests between the critically endangered Fitzroy Falls Spiny Crayfish (Euastacus dharawalus) and the invasive yabby (Cherax destructor) in a controlled laboratory setting. Although C. destructor has been listed as a key threatening process for E. dharawalus, the magnitude and nature of its impact have not been formerly assessed. We recorded the frequency and intensity of aggressive interactions between the species, as well as the winner of the contest and subsequent dominance during staged encounters. In addition to this, we recorded the time individuals spent consuming food and actively moving on the substratum. Contrary to our predictions, the frequency of aggressive behaviours performed by the two species did not significantly differ, but E. dharawalus engaged in more intensely aggressive behaviours and was less submissive than C. destructor. As a result, E. dharawalus won significantly more contests than its invasive rival and subsequently achieved a higher dominance score overall. Despite this result, C. destructor spent significantly more time consuming food than did E. dharawalus. These results suggest that dominance in agonistic contests did not translate into dominance over food resources in our study. Ultimately, reduced access to food, combined with the costs of agonistic contests including injury and the relatively low reproductive rates of E. dharawalus indicate that C. destructor may have a negative effect on the survival and persistence of the critically endangered E. dharawalus. [ABSTRACT FROM AUTHOR]

Rocky intertidal shores are diverse ecosystems that have been extensively studied, yet there is a surprising lack of knowledge on the methods best suited to quantifying species abundance, diversity and assemblages. We compared visual census, unbaited remote underwater video (mini-RUV), baited remote underwater video (mini-BRUV) and draining/collection methods, with the goal of quantifying the effectiveness of non-invasive methods over more typical invasive methods for quantifying rockpool fish assemblages. In addition, we assessed the optimal set time of video deployment for mini-RUV and mini-BRUV. Fieldwork was undertaken from May-June 2016 using 20 rockpools at seven locations on the SE coast of NSW, Australia. Following standardisation of methods, visual census detected the lowest abundance of fishes whereas hand collection detected the highest out of any method. Increasing sampling time of mini-RUV and mini-BRUV from 10 to 25 min improved their effectiveness, with mini-BRUV detecting comparable abundances to invasive hand collection. The methods did not differ with respect to species richness however. Further, 25 min of mini-BRUV yielded greater detection of common species than hand collection. All together, these results suggest that mini-BRUV is the best method if the goal is to provide accurate estimates of overall abundance, richness and assemblages with minimal disturbance to rockpools, with a preferred set time of 25 min (and at least 15 min). The ability to conduct rapid and non-invasive species surveys of natural rockpool fish communities is an important conservation and management tool given that these habitats can be home to a variety of commercially important and rare species. [ABSTRACT FROM AUTHOR]

Social organization is a key factor influencing a species’ foraging and reproduction, which may ultimately affect their survival and ability to recover from catastrophic disturbance. Severe weather events such as cyclones can have devastating impacts to the physical structure of coral reefs and on the abundance and distribution of its faunal communities. Despite the importance of social organization to a species’ survival, relatively little is known about how major disturbances such as tropical cyclones may affect social structures or how different social strategies affect a species’ ability to cope with disturbance. We sampled group sizes and coral sizes of group-forming and pair-forming species of the Gobiid genus Gobiodon at Lizard Island, Great Barrier Reef, Australia, before and after two successive category 4 tropical cyclones. Group sizes of group-forming species decreased after each cyclone, but showed signs of recovery four months after the first cyclone. A similar increase in group sizes was not evident in group-forming species after the second cyclone. There was no change in mean pair-forming group size after either cyclone. Coral sizes inhabited by both group- and pair-forming species decreased throughout the study, meaning that group-forming species were forced to occupy smaller corals on average than before cyclone activity. This may reduce their capacity to maintain larger group sizes through multiple processes. We discuss these patterns in light of two non-exclusive hypotheses regarding the drivers of sociality in Gobiodon, suggesting that benefits of philopatry with regards to habitat quality may underpin the formation of social groups in this genus. [ABSTRACT FROM AUTHOR]

Determining the extent of repeatable differences in the behavior of animals and the factors that influence behavioral expression is important for understanding individual fitness and population processes, thereby aiding in species conservation. However, little is known about the causes of variation in the repeatability of behavioral differences among species because rarely have comparative studies been undertaken to examine the repeatability of behavioral differences among individuals within their natural ecological settings. Using two species of endemic subtropical anemonefishes, Amphiprion mccullochi and A. latezonatus at Lord Howe and North Solitary Islands, Australia, we conducted an in situ comparative analysis of personality traits, examining the repeatability of boldness, sociability and aggression as well as the potential role of environmental and social factors on behavioral expression. For A. mccullochi, only boldness and aggression were highly repeatable and these behaviors formed a behavioral syndrome. For A. latezonatus, none of the three behaviors were repeatable due to low-inter-individual variation in behavior. We suggest that the harsher and more variable environmental and social conditions experienced by A. latezonatus have resulted in reduced repeatability in behavior, in contrast to A. mccullochi which typically inhabits a more stable lagoonal reef environment. Additionally, group size and size rank, rather than nearest-neighbor distance and anemone size, influenced the expression of these behaviors in both species, suggesting that behavioral variation was more sensitive to social than environmental factors. Overall, differences in repeatability between these closely related species likely reflect adaptations to contrasting environmental and social conditions, although alternative explanations must be considered. The differences in behavioral consistency between these two endemic anemonefishes could lead to disparity in their resilience to environmental or social change in the future. [ABSTRACT FROM AUTHOR]

Competition for limiting resources is a fundamental and well-established driver of niche partitioning, which in turn promotes species coexistence and biodiversity. Although contests are a well-known behavioural mechanism by which organisms compete over limiting resources, there has been surprisingly little application of contest theory to understanding interspecific interactions, niche partitioning, species coexistence and biodiversity., We investigated the link between contest dynamics and community structure using two intertidal rockpool fishes, Bathygobius cocosensis (Gobiidae) and Lepidoblennius haplodactylus (Tripterygiidae), as model species. We assessed the abundance and distribution of the two species on intertidal rocky shores of South-East Australia, and whether distribution patterns were related to abiotic variables. We then conducted interspecific contest experiments between pairs of B. cocosensis and L. haplodactylus of varying size and sex under high and low dissolved oxygen levels to assess the competitive dominance of the species. To relate these results to community structure, we quantified temporal patterns of rockpool fidelity of each species in situ., Field surveys revealed that B. cocosensis was most prevalent in rockpools with higher dissolved oxygen, and L. haplodactylus was most prevalent in rockpools that contained no B. cocosensis. Contest experiments revealed that B. cocosensis displayed higher resource holding power than L. haplodactylus regardless of size asymmetry, sex or dissolved oxygen concentration, although contest intensity was influenced by relative body size of competing individuals. Furthermore, the microhabitat preference of L. haplodactylus was modulated in the presence of B. cocosensis. In the field, B. cocosensis displayed higher rockpool fidelity than L. haplodactylus., In light of these findings, we propose that B. cocosensis is the superior competitor but persistence of both species is likely facilitated by low-cost contest resolution strategies, plasticity in microhabitat preference, negative spatial co-variation and interspecific variation in dispersal and corresponding home range sizes., By using contest theory to understand the dynamics of interspecific contests, insight has been gained into how habitat is partitioned, species coexist and ultimately how biodiversity is maintained., A is available for this article. [ABSTRACT FROM AUTHOR]

Predicting the impacts of climate change to biological systems requires an understanding of the ability for species to acclimate to the projected environmental change through phenotypic plasticity. Determining the effects of higher temperatures on individual performance is made more complex by the potential for environmental conditions experienced in previous and current generations to independently affect phenotypic responses to high temperatures. We used a model coral reef fish ( Acanthochromis polyacanthus) to investigate the influence of thermal conditions experienced by two generations on reproductive output and the quality of offspring produced by adults. We found that more gradual warming over two generations, +1.5°C in the first generation and then +3.0°C in the second generation, resulted in greater plasticity of reproductive attributes, compared to fish that experienced the same increase in one generation. Reproduction ceased at the projected future summer temperature (31.5°C) when fish experienced +3.0°C for two generations. Additionally, we found that transgenerational plasticity to +1.5°C induced full restoration of thermally affected reproductive and offspring attributes, which was not possible with developmental plasticity alone. Our results suggest that transgenerational effects differ depending on the absolute thermal change and in which life stage the thermal change is experienced. [ABSTRACT FROM AUTHOR]

Anthropogenic climate change is expected to result in dramatic shifts in the abiotic conditions within estuaries, including an elevation of temperature and salinity levels. Even so, few studies have addressed the impacts of multiple abiotic stressors on the behaviour and life history of key estuarine species, such as those of biological and commercial importance. Here we used a cross-factored experimental design to tease apart the effects of temperature and salinity on intraspecific aggression and growth rates of a native estuarine fish species, the Australian bass ( Macquaria novemaculeata). Juvenile bass were exposed to one of four treatment conditions: 1) baseline temperature and salinity, 2) elevated temperature, 3) elevated salinity, and 4) elevated temperature and salinity. Elevated salinity increased rates of aggression, and elevated temperature decreased rates of growth, although the effects of both factors were mediated by the body size of individual bass. These results therefore highlight complex and variable effects of abiotic stressors and body size, emphasising the importance of considering individual-level attributes when evaluating the impacts of climate change on estuarine fishes. [ABSTRACT FROM AUTHOR]

In social groups, hierarchies are the fundamental organizational unit and integral to the structure of social groups. For many social fishes, rank is determined by body size and conflict over rank is resolved via aggressive threats from dominants and growth restraint by subordinates. However, this balance may be offset by an alteration of abiotic factors, such as elevated temperature expected from climate change, which could thereby disrupt the usual mechanisms of conflict resolution. Here, we determined the effect of elevated temperature on hierarchy structure, stability, and conflict resolution in the Eastern mosquitofish, Gambusia holbrooki. Body size was significantly related to dominance rank, and aggression was more commonly directed toward subordinates and was heightened between individuals of adjacent rank, demonstrating that conflict over rank occurs in size-based hierarchies. Temperature did not affect overall levels or directionality/adjacency of aggression but substantially altered subordinate growth patterns. In only the high-temperature groups, growth rates of subordinates decreased as the size ratio between themselves and their immediate dominant approached 1.0, whereas growth rates of dominants were unaffected. This unique finding suggests that only under high temperatures, subordinates may adopt growth regulation to resolve conflict, when the costs of conflict with dominants are greater. This provides the first causal link between abiotic stressors and changes to hierarchical structure and functioning, providing a springboard for further research into implications of temperature-dependent subordinate growth alteration at higher levels of ecological organization. [ABSTRACT FROM AUTHOR]

A major focus in evolutionary ecology lies in explaining the evolution and maintenance of social systems. Although most theoretical formulations of social system evolution were initially inspired by studies of birds, mammals, and insects, incorporating a wider taxonomie perspective is important for testing deeply entrenched theory. Here, we review the contribution of studies of habitat-specialist coral reef fishes to our understanding of the evolutionary ecology of animal social systems. These fishes are ecologically similar but display remarkable variation in mating systems, social organization, and sex allocation strategies. By reviewing recent research, we demonstrate their amenability for experimental testing of key concepts in social evolution and for generating novel insights, including the ultimate reasons for female reproductive suppression, group living, and bidirectional sex change. Habitat-specialist reef fishes are a tried and tested group of model organisms for advancing our understanding of the evolution and ecology of social systems in animals. [ABSTRACT FROM AUTHOR]

The number of group members in an animal society can have a major influence on group members' life history, survival, and reproductive success. Identifying the factors that limit group size is therefore fundamental for a complete understanding of social behavior. Here, I examined the relationships between resource availability, social conflict, and group size in the coral-dwelling fish, Paragobiogon xanthosomus (Gobiidae). The size of the largest (breeding) female and the minimum size difference required for hierarchy stability strongly but not perfectly predicted maximum group size, suggesting that social conflicts and hierarchy structure set the upper limit on group size. Deviations in group size around the predicted maximum were explained by variation in average body size ratios but not by variation in coral size, suggesting that coral size does not directly influence group size. In contrast, coral size was a significant predictor of body size ratios, and possible explanations for this relationship are discussed. Group size may be limited by the social conflicts that characterize size-based dominance hierarchies. Ecological factors, namely coral size, may in turn play an indirect role via an effect on body size ratios. [ABSTRACT FROM AUTHOR]

The conundrum of why subordinate individuals assist dominants at the expense of their own direct reproduction has received much theoretical and empirical attention over the last 50 years. During this time, birds and mammals have taken centre stage as model vertebrate systems for exploring why helpers help. However, fish have great potential for enhancing our understanding of the generality and adaptiveness of helping behaviour because of the ease with which they can be experimentally manipulated under controlled laboratory and field conditions. In particular, the freshwater African cichlid, Neolamprologus pulcher, has emerged as a promising model species for investigating the evolution of cooperative breeding, with 64 papers published on this species over the past 27 years. Here we clarify current knowledge pertaining to the costs and benefits of helping in N. pulcher by critically assessing the existing empirical evidence. We then provide a comprehensive examination of the evidence pertaining to four key hypotheses for why helpers might help: (1) kin selection; (2) pay-to-stay; (3) signals of prestige; and (4) group augmentation. For each hypothesis, we outline the underlying theory, address the appropriateness of N. pulcher as a model species and describe the key predictions and associated empirical tests. For N. pulcher, we demonstrate that the kin selection and group augmentation hypotheses have received partial support. One of the key predictions of the pay-to-stay hypothesis has failed to receive any support despite numerous laboratory and field studies; thus as it stands, the evidence for this hypothesis is weak. There have been no empirical investigations addressing the key predictions of the signals of prestige hypothesis. By outlining the key predictions of the various hypotheses, and highlighting how many of these remain to be tested explicitly, our review can be regarded as a roadmap in which potential paths for future empirical research into the evolution of cooperative breeding are proposed. Overall, we clarify what is currently known about cooperative breeding in N. pulcher, address discrepancies among studies, caution against incorrect inferences that have been drawn over the years and suggest promising avenues for future research in fishes and other taxonomic groups. [ABSTRACT FROM AUTHOR]

The article discusses the results of a study that determined the function and causes of variation in social aggression using Neolamprologus pulcher, the group-living cichlid fish. The study material and methods are discussed, including a linear regression test between helper rank and the frequency of aggression. The study showed that subordinates became more aggressive after they ascended in rank. Also, female ascenders showed more rapid increases in aggression than males.

Kin selection plays an important role in the evolution of social behaviour in terrestrial systems. The extent to which kin selection influences the evolution of social behaviour in marine systems is largely unexplored. Generally, it is considered that kin selection is irrelevant in marine systems, because it is assumed that the dispersing larval phase of marine organisms will break up kin associations. Here, we challenge this assumption and investigate the opportunity for kin selection in a coral reef fish: the humbug damselfish Dascyllus aruanus. This fish lives in groups composed of a large male and a number of smaller females and nonbreeders. We use 10 polymorphic microsatellite loci to assess the relatedness of 265 individuals from 35 groups. The mean coefficient of relatedness among group members is 0.01 ± 0.04, suggesting that individuals are not associated with close relatives. However, the distribution of pairwise relatedness of individuals within groups has an overabundance of positive values, and indicates that there might be 35 pairs of close relatives within groups. Further analyses reveal that close relatives likely are similar in size and small in size, suggesting that they might have recruited together. We conclude that it is possible for kin selection to operate in D. aruanus, but kin recognition will be a prerequisite for such selection. This study reveals that individuals can be associated with close relatives, and there is a hidden potential for kin selection, during certain parts of the life cycle of coral reef fishes. [ABSTRACT FROM AUTHOR]

We investigated the inter-relationships between coral colony size, social group size, mating system, and patterns of sex allocation in the pygmy coral croucher, Caracanthus unipinna (Caracanthidae), an obligate coral-dwelling fish. Histological examination of the gonads from all individuals in social groups revealed that the predominant mating system was harem polygyny. However, both group size and mating system co-varied with coral colony size, with pair forming and monogamy occurring on small corals and group forming and harem polygyny on large corals. This species therefore displays mating system plasticity in response to varying habitat patch size. Within-group sexual size dimorphism and individual gonad structure indicate that C. unipinna is also likely to be a protogynous hermaphrodite. These social and reproductive features of C. unipinna contrast with some other coral-dwelling fishes, which display a lack of social and mating system plasticity in response to habitat patch size, and either bi-directional or protandrous sex change. Possible reasons for this dichotomy include differences in spawning mode, parental care and levels of intrasexual aggression. [ABSTRACT FROM AUTHOR]

Many courses aim to promote reflective thinking or reflection upon practice, but there is a scarcity of readily usable instruments to determine whether students engage in reflective thinking and, if so, to what extent. This paper reports the development and testing of such an instrument. To ensure validity, the constructs measured were derived from the extensive literature on reflective thinking, particularly the writing of Mezirow. A combination of the literature review and initial testing led to the development of a four-scale instrument measuring four constructs; habitual action, understanding, reflection and critical reflection. The final version of the instrument was tested with a sample of 303 students from eight classes of a health science faculty. The reliability of the scales was established by acceptable Cronbach alpha values. Confirmatory factor analysis showed a good fit to the proposed four-factor structure. Comparison of mean scores between the eight classes showed predicted significant differences on each of the four scales between undergraduate and postgraduate students. [ABSTRACT FROM AUTHOR]

How should courses be arranged if students are to be encouraged to reflect upon their practice through the writing of reflective journals? This research question was addressed in action research studies of five courses in the allied health areas. The five studies fed into one overall project which synthesised findings from the five subprojects through the critical discussions of the participants. It was discovered that students needed an introduction to and feedback upon reflective writing as it differed from other types of writing required in academic courses. For reflective writing to be taken seriously, it needed to be an integral part of the course. Issues such as the disclosure of journal entries and the assessment of reflective writing needed to be handled sensitively. The courses studied evolved positions on these issues which attempted to balance dichotomous concerns. [ABSTRACT FROM PUBLISHER]

To determine whether students are engaged in reflective practice it is necessary to have some means of identifying reflective thought and a measure of the depth of reflective thinking. Several measures of reflectivity have been proposed but there appears to be no widely accepted and clearly formulated procedure for determining levels of reflective thinking from students' written reflective journals. In this study we propose a scheme for estimating the quality of reflective thinking in students' writing in reflective journals, using categories based on Mezirow's work on reflective thinking. In an initial test of the scheme, reasonable levels of agreement were obtained from eight judges. Disagreements over coding resulted from differing interpretations of the significance of what students had written rather than from a lack of precision in the guidelines for coding categories. A second test, using students' reflective papers, showed acceptable levels of reliability between four assessors. The method is recommended for both assessing students and evaluating courses in programs which aim to develop reflective thinking. [ABSTRACT FROM AUTHOR]

This study examines the ways in which reflective journal writing can be used to promote critical discussion in small group tutorials. Conclusions are drawn by synthesizing findings from action research studies of five professional education courses in the allied health area. It was found that reflective writing serves as a valuable stimulus for discussion and that the two in combination lead to fresh insights for students and promote critical reflection. The study examines the impact upon critical discussion of variables such as disclosure, ground‐rules, group size, physical arrangement of classrooms, inter‐group interaction and the role of the tutor. In formulating arrangements for journal writing and tutorials, it was often necessary to develop an intelligent working position between apparent dichotomies. [ABSTRACT FROM PUBLISHER]

The article presents a study that examines the group membership decisions of Neolamprologus pulcher, a group-living cichlid. Also studied are the aggressive, submissive and social interactions between focal and resident helpers. The authors discovered the preference of subordinate helpers for joining familiar groups while helpers opted groups containing larger, more dominant individuals despite receiving more aggression within the group. The results highlighted the complex decision process in N. pulcher when choosing among groups.