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Obtaining nesting material presents an optimal foraging problem, collection of materials incurs a cost in terms of risk of predation and energy spent and individuals must balance these costs with the benefits of using that material in the nest. The hazel dormouse, Muscardinus avellanarius is an endangered British mammal in which both sexes build nests. However, whether material used in their construction follows the predictions of optimal foraging theory is unknown. Here, we analyze the use of nesting materials in forty two breeding nests from six locations in Southwest England. Nests were characterized in terms of which plants were used, the relative amount of each plant, and how far away the nearest source was. We found that dormice exhibit a preference for plants closer to the nest, but that the distance they are prepared to travel depends on the plant species. Dormice traveled further to collect honeysuckle Lonicera periclymenum , oak Quercus robur , and beech Fagus sylvatica than any other plants. Distance did not affect the relative amount used, although the proportion of honeysuckle in nests was highest, and more effort was expended collecting honeysuckle, beech, bramble Rubus fruticosus and oak compared to other plants. Our results suggest that not all aspects of optimal foraging theory apply to nest material collection. However, optimal foraging theory is a useful model to examine nest material collection, providing testable predictions. As found previously honeysuckle is important as a nesting material and its presence should be taken account when assessing suitability of sites for dormice. [ABSTRACT FROM AUTHOR]

Skilful fighting encompasses an individual's ability not only to perform agonistic behaviours accurately and efficiently, but also to choose the most appropriate behaviour or tactic from its repertoire based on the information available. The efficacy of different tactics may depend both on the behaviour of the opponent and on the individual's internal state, for example a specific behaviour may become less effective over time as fatigue sets in. Furthermore, because fights are dynamic interactions, the ability to choose the appropriate tactic will require rapid information processing and may thus be constrained by an individual's cognitive ability. Here, we conducted a three-phase experiment to investigate the effects of reduced performance capacity induced by exposure to hypoxia and decision-making speed on skilful fighting in the European hermit crab, Pagurus bernhardus. During fights attackers attempt to elicit an eviction either by rapping on the defender's shell or by rocking the defender's shell back and forth. By analysing the effect of exposure to hypoxia and decision-making speed on the relative use of these tactics, we show that contrary to our prediction, neither performance capacity nor decision-making speed alone predicted the type of behaviour performed. Rather, these two traits interacted to determine the amount of effort (raps and rocks) attackers needed to exert to elicit an eviction. Furthermore, we show that while neither performance capacity nor decision-making speed predicted skill when fights were analysed as a whole, the effects of these variables became apparent when analysing the change in accuracy as fights progressed, likely due to the accumulating effects of fatigue. • The performance of agonistic behaviours varies in terms of vigour and skill. • Vigour is linked to energetic status, but the underpinnings of skill are unknown. • We explore the effects of performance capacity and decision-making speed on skill. • We measure two aspects of skill, accuracy and appropriateness (choice of tactics). • We find that performance capacity and decision-making speed impact skill over time. [ABSTRACT FROM AUTHOR]

Skill, the ability to perform a challenging behaviour well, has been shown to be an important determinant of success in a variety of contexts, including human sports, animal courtship and, most recently, animal contests. Because skilful movement requires precise motor control, skill is assumed to be underpinned by traits that determine these abilities. However, while these traits determine an individual's potential to perform effective movements (known as technique), this potential may not translate into skilful fighting due to interference from the opponent. Here, we investigated the relationship between technique and skill using the European hermit crab, Pagurus bernhardus. By examining the spatial distribution of shell raps, we found that, on average, technique exhibited during a 'training' fight predicted the level of skill displayed in a real contest. However, our results also demonstrated substantial among-individual variation in the direction of change across the two fights, with some individuals exhibiting better technique than skill and others showing the opposite pattern. Finally, we found that winners, but not losers, progressively adapted their targeting of strikes when faced with a fully functional opponent. Our results indicate that skill is a combination of innate technique and the ability to adapt to an opponent's behaviour. • Skill has recently been shown to be a key determinant of fighting success. • Skill is assumed to rely on innate capacities for motor control (technique). • But opponent interference may impede an individual's ability to perform skilfully. • Here we show that innate technique is indicative of the ability to fight skilfully. • We also find that skilful fighting relies on the ability to adapt to your opponent. [ABSTRACT FROM AUTHOR]

Despite widespread variation in life span across species, three clear patterns exist: sex differences in life span are ubiquitous, life span is commonly traded against reproduction, and nutrition has a major influence on these traits and how they trade‐off. One process that potentially unites these patterns is intralocus sexual conflict over the optimal intake of nutrients for life span and reproduction. If nutrient intake has sex‐specific effects on life span and reproduction but nutrient choice is genetically linked across the sexes, intralocus sexual conflict will occur and may prevent one or both sexes from feeding to their nutritional optima.Here we determine the potential for this process to operate in the decorated cricket Gryllodes sigillatus. Using the Geometric Framework for Nutrition, we restrict male and female crickets to diets varying in the ratio of protein to carbohydrates and total nutrient content to quantify the effects on life span and daily reproductive effort in the sexes. We then use inbred lines to estimate the quantitative genetic basis of nutrient choice in males and females. We combine the nutrient effects and genetic estimates to predict the magnitude of evolutionary constraint for these traits in each sex. Finally, we present male and female crickets with a much broader range of diet pairs to determine how the sexes actively regulate their intake of nutrients.We show that protein and carbohydrate intake have contrasting effects on life span and reproduction in the sexes and that there are strong positive intersexual genetic correlations for the intake of these nutrients under dietary choice. This is predicted to accelerate the evolutionary response of nutrient intake in males but constrain it in females, suggesting they are losing the conflict. Supporting this view, males and females regulate nutrient intake to a common nutrient ratio that was not perfectly optimal for life span or reproduction in either sex, especially in females.Our findings show that intralocus sexual conflict over the optimal intake of nutrients is likely to be an important process generating sex differences in life span and reproduction and may help explain why females age faster and live shorter than males in G. sigillatus. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Whenever resources are limited and indivisible, fighting will evolve as a means to resolve ownership. Among such resources are mates, and individuals (usually males) of many species compete agonistically with rivals in order to gain access to potential mates. However, securing access is not necessarily enough to guarantee a mating or, if a mating is obtained, to guarantee that it is effective for securing reproductive success. Thus, in addition to fighting, individuals participate in a wealth of behaviours to maximize their reproductive success, from courtship to sperm competition to mate guarding. In recent years, the striking parallels between fighting and mating behaviour have become a subject of discussion. In particular, insights have been drawn from the predictions of contest theory to help us understand the use of repetitive signalling in courtship. Here, we take this discussion further, highlighting similarities between fighting and mating in the use of dynamic repeated behaviours, which function to (1) advertise quality and (2) convince or coerce an individual to relinquish the contested resource (gametes in terms of mating). We focus specifically on a performance trait of emerging interest in the field of animal contests, skill. We identify behaviours used throughout the mating process in which skill is likely to be of importance for securing success, and highlight key questions for future study. • Fighting and mating both involve the performance of repeated behaviours. • Performance rate (vigour) and skill are of known importance for fighting success. • Here, we discuss the possible role of skill in determining mating success. • We highlight functional similarities between fighting and mating behaviours. • We then identify mating behaviours for which a role for skill is strongly implied. [ABSTRACT FROM AUTHOR]

Evidence of alloparental care during the incubation stage has largely been demonstrated for species that incubate their offspring externally in a nest. Alloparental care in these species generally consists of the rearing of mixed broods which contain a low proportion of "foreign" young alongside the host's own offspring. However, many animals, including sea anemones, incubate offspring either on or within their bodies. The beadlet anemone Actinia equina incubate their young internally, and as many sea anemones are capable of reproducing both sexually and asexually, the origin of these internally brooded young has been the subject of much debate. While genetically identical young are brooded internally under the juvenile stage, it is thought that those produced sexually are released as larvae into the water and must return to the gastric cavity of an adult in order for metamorphosis to occur. As the likelihood of a planula larva finding its way back to its parent is slim, this suggests that alloparental care may play a role in the survival of juveniles in this species, a hypothesis first suggested a century ago but rarely tested. Here, using highly polymorphic microsatellite markers, we find evidence of alloparental care in A. equina. Our results indicate that while a high proportion of juveniles were genetically identical to their brooding adult, the remaining juveniles showed stark genetic differences to their brooding adult. These juveniles shared far fewer alleles with their "parent" than expected under sexual reproduction, indicating that they were not the adult's offspring. Furthermore, we found variation in the genetic composition of broods, which consisted either of (a) entirely genetically identical individuals, (b) a mix of unique individuals and clonemates or (c) entirely unique individuals, that is no shared genotype. Our results thus indicate that adult A. equina tolerate the presence of non‐offspring within their gastric cavity and furthermore that they may incubate entirely "foreign" broods. [ABSTRACT FROM AUTHOR]

Understanding the determinants of fighting ability (or resource-holding potential, RHP) is key to elucidating the evolution of aggressive behaviour, as current tests of contest theory rely on realistic proxies for overall RHP. Traditionally, RHP is considered equivalent to body size but it is increasingly clear that a wider range of morphological and physiological traits contribute to fighting ability. In situations analogous to contests, such as courtship displays in animals and competitive sport in humans, the role of skill has long been appreciated but this component has been neglected in analyses of animal fights. Here, we investigated two spatial components of skill, accuracy and precision, during shell fights in hermit crabs, where an attacker repeatedly strikes (raps) its shell against that of a defender. By analysing the points of impact of these strikes, we found that attackers that rapped with coarse-scale accuracy were more likely to win the fight, indicating that the ability to target a 'sweet spot' on the defender's shell is an important determinant of contest success. Furthermore, we found that this element of skill correlated with temporal performance (vigour). Taken together these results show that spatial skill is an RHP component. Moreover, in contrast to the traditional assumption that fighting ability is equivalent to body size, RHP is actually underpinned by a suite of interlinked traits including performance capacities, morphology and skill. • Fighting often involves the repeated performance of agonistic behaviours. • Individuals may vary in how skilfully they perform such behaviours. • We investigate the link between spatial skill and fighting success in hermit crabs. • We find that winners perform rapping behaviour more skilfully than losers. • Our results indicate that skill is tightly correlated with other fighting traits. [ABSTRACT FROM AUTHOR]

Theoretical models of animal contests such as the Hawk-Dove game predict that variation in fighting behavior will persist due to mixed evolutionarily stable strategies (ESS) under certain conditions. However, the genetic basis for this variation is poorly understood and a mixed ESS for fighting can be interpreted in more than one way. Specifically, we do not know whether variation in aggression within a population arises from among-individual differences in fixed strategy (determined by an individual's genotype—direct genetic effects [DGEs]), or from within-individual variation in strategy across contests. Furthermore, as suggested by developments of the original Hawk-Dove model, within-individual variation in strategy may be dependent on the phenotype and thus genotype of the opponent (indirect genetic effects—IGEs). Here we test for the effect of DGEs and IGEs during fights in the beadlet sea anemone Actinia equina. By exploiting the unusual reproductive system of sea anemones, combined with new molecular data, we investigate the role of both additive (DGE + IGE) and non-additive (DGE × IGE) genetic effects on fighting parameters, the latter of which have been hypothesized but never tested for explicitly. We find evidence for heritable variation in fighting ability and that fight duration increases with relatedness. Fighting success is influenced additively by DGEs and IGEs but we found no evidence for non-additive IGEs. These results indicate that variation in fighting behavior is driven by additive indirect genetic effects (DGE + IGE), and support a core assumption of contest theory that strategies are fixed by DGEs. [ABSTRACT FROM AUTHOR]

Animals utilize an incredible array of traits for offence and defence during conflict. These traits range from exaggerated morphological structures such as the antlers of stags and the horns of beetles, to an arsenal of noxious chemicals emitted, secreted, and injected. However, the breadth of these traits appears to be underappreciated in our current thinking about aggression in animals. Use of the term "weapon" in the current literature is largely restricted to studies of conspicuous morphological structures used by males during contests over access to females, and as a result, our understanding of other types of weapons is limited. In this article, I explore the diversity of traits utilized by animals to manipulate and control the behavior of other individuals in a number of agonistic contexts, with the aim to encourage a reappraisal of the way in which behavioral and evolutionary biologists view animal weapons. I discuss the advantages of including this broader range of traits in studies of animal weaponry and explore the unifying features that distinguish animal weapons from other traits. [ABSTRACT FROM AUTHOR]

An individual's performance during a fight is influenced by a combination of their capacity and willingness to compete. While willingness to fight is known to be determined by both intrinsic and extrinsic drivers, an individual's capacity to fight is generally thought of as solely intrinsic, being driven by a host of physiological factors. However, evidence indicates that variation in fighting ability can also be generated through exposure to different environmental conditions. Environmental contributions to fighting ability may be particularly important for animals living in spatially and temporally heterogeneous habitats, in which fights can occur between rivals recently exposed to different environmental conditions. The rapidly changing environment experienced within intertidal zones, for example, means that seawater parameters, including dissolved oxygen content and temperature, can vary across small spatial and temporal scales. Here, we investigated the relative importance of these extrinsic contributions to fighting ability and resource value on contest dynamics in the beadlet sea anemone Actinia equina. We manipulated the extrinsic fighting ability of both opponents (through dissolved oxygen concentration prior to fights) and resource value (through seawater flow rate during the fight). Our results indicate that the extrinsic fighting ability of both opponents can interact with resource value to drive escalation patterns and that extrinsic drivers can be more important in determining contest dynamics than the intrinsic traits commonly studied. Our study highlights the need to combine data on intrinsic state and extrinsic conditions in order to gain a more holistic view of the factors driving contest behaviour. [ABSTRACT FROM AUTHOR]

The ability to mitigate the costs of engaging in a fight will depend on an individual's physiological state. However, the experience of fighting itself may, in turn, affect an individual's state, especially if the fight results in injury. Previous studies have found a correlation between immune state and fighting success, but the causal direction of this relationship remains unclear. Does immune state determine fighting success? Or does fighting itself influence subsequent immune state? Using the beadlet anemone, Actinia equina, we disentangled the cause and effect of this relationship, measuring immune response once pre-fight and twice post-fight. Contrary to previous findings, pre-fight immune response did not predict fighting success, but rather predicted whether an individual used its weapons during the fight. Furthermore, weapon use and contest outcome significantly affected post-fight immune response. Individuals that used their weapons maintained a stable immune response following the fight, whereas those that fought non-injuriously did not. Furthermore, although winners suffered a reduction in immune response similar to that of losers immediately postfight, winners began to recover pre-fight levels within 24 h. Our findings indicate that immune state can influence strategic fighting decisions and, moreover, that fight outcome and the agonistic behaviours expressed can significantly affect subsequent immunity. [ABSTRACT FROM AUTHOR]

Fighting experience (specifically winning or losing a fight) can significantly alter boldness, a component of resource-holding potential (RHP). Previous studies have shown that both the repeatability of boldness and mean-level boldness can be affected by fighting experience and that these effects are strongest in the recipients of agonistic behaviour. However, whether these postfight changes in boldness impact future contest success and whether subsequent contests further affect boldness remain unknown. Furthermore, little is known about the effects of the specific tactics used within a fight (within-fight experience) and how these might influence future fight performance and boldness. Here, we investigated the relationship between fighting success and boldness (measured as recovery time when startled) across repeated contests in the beadlet sea anemone, Actinia equina , measuring boldness on five occasions before, between and after two contests. We found that boldness (both repeatability and mean-level) was generally robust to the effects of fighting experience, apart from a decrease in the immediate boldness of losers after their second fight. Furthermore, we found that while prefight boldness significantly predicted fighting success and the level of aggression used in an individual's first fight, it did not predict victory or aggression in the second fight. Our findings thus indicate that different traits may be important in determining fighting success in consecutive fights and, moreover, that fighting experience may alter which traits contribute to an individual's RHP. [ABSTRACT FROM AUTHOR]

What attributes make some individuals more likely to win a fight than others? A range of morphological and physiological traits have been studied intensely but far less focus has been placed on the actual agonistic behaviours used. Current studies of agonistic behaviour focus on contest duration and the vigour of fighting. It also seems obvious that individuals that fight more skilfully should have a greater chance of winning a fight. Here, we discuss the meaning of skill in animal fights. As the activities of each opponent can be disrupted by the behaviour of their rival, we differentiate among ability, technique and skill itself. In addition to efficient, accurate and sometimes precise movement, skilful fighting also requires rapid decision-making, so that appropriate tactics and strategies are selected. We consider how these different components of skill could be acquired, through genes, experiences of play-fighting and of real fights. Skilful fighting can enhance resource holding potential (RHP) by allowing for sustained vigour, by inflicting greater costs on opponents and by minimizing the chance of damage. Therefore, we argue that skill is a neglected but important component of RHP that could be readily studied to provide new insights into the evolution of agonistic behaviour. [ABSTRACT FROM AUTHOR]

Theoretical models of injurious animal contests, such as the cumulative assessment model (CAM), predict that an individual's decision to give up and retreat from a fight is determined by reaching a maximum cost threshold ( C max ). Under this model, an individual gives up when the accumulated costs of persisting exceed this threshold. CAM predicts that the velocity with which C max is reached depends on both the energetic (physiological) costs of remaining in the fight and the damage costs of injuries received. Here we propose that damage costs are accumulated not only by receiving injuries, but in some cases also by inflicting injury (attacking). We argue that these self-inflicted damage costs need to be incorporated into theoretical frameworks to fully understand what drives an individual to make the decision to give up, and we call for further research into this area. [ABSTRACT FROM AUTHOR]

Same-sex sexual behaviour (SSB) is widespread across taxa. One adaptive hypothesis to explain the occurrence and maintenance of SSB is that it acts to intensify or diminish aggression by providing males with a means to reinforce or resolve dominance. However, evidence for this hypothesis is very limited across taxa and the possibility that SSB acts as an extension of intrasexual competition remains contentious. We investigated the role of SSB in intensifying or diminishing aggression in the broad-horned flour beetle, Gnatocerus cornutus . We tested the hypothesis that SSB is an extension of male–male competition by observing how the occurrence of SSB and the stability of SSB courtship roles (i.e. whether males switched between mounting and being mounted) influenced levels of aggression within pairs. We found that, typically, males rapidly establish fixed SSB roles and moreover that the occurrence of SSB and the stability of SSB roles had a highly significant effect on levels of aggression observed within pairs. Pairs in which one male consistently mounted the other showed significantly lower levels of aggression than pairs in which neither male exhibited SSB or in which males continuously switched SSB roles and attempted to mount each other. Furthermore, males that were consistently on the receiving end of SSB demonstrated lower propensity to court females and had a lower mating success than active males. This pattern was analogous to that found in loser males as a result of fighting. Males that lost fights also courted less and had lower mating success than males that won fights. Our findings provide the first empirical support for the hypothesis that SSB is an extension of male–male competition. Furthermore, our results suggest that SSB may act as a display, allowing males to resolve dominance hierarchies without escalating into an injurious fight. [ABSTRACT FROM AUTHOR]

Males can gather information on the risk and intensity of sperm competition from their social environment. Recent studies have implicated chemosensory cues, for instance cuticular hydrocarbons (CHCs) in insects, as a key source of this information. Here, using the broad-horned flour beetle (Gnatocerus cornutus), we investigated the importance of contact-derived rival male CHCs in informing male perception of sperm competition risk and intensity. We experimentally perfumed virgin females with male CHCs via direct intersexual contact and measured male pre- and post-copulatory investment in response to this manipulation. Using chemical analysis, we verified that this treatment engendered changes to perfumed female CHC profiles, but did not make perfumed females "smell" mated. Despite this, males responded to these chemical changes. Males increased courtship effort under low levels of perceived competition (from 1-3 rivals), but significantly decreased courtship effort as perceived competition rose (from 3-5 rivals). Furthermore, our measurement of ejaculate investment showed that males allocated significantly more sperm to perfumed females than to control females. Together, these results suggest that changes in female chemical profile elicited by contact with rival males do not provide males with information on female mating status, but rather inform males of the presence of rivals within the population and thus provide a means for males to indirectly assess the risk of sperm competition. [ABSTRACT FROM AUTHOR]

The article presents the results of a study examining the impact of order of visualization on students' particulate-level explanations for experiments including diffusion-effusion. The author compares the results of macroscopic versus particle views on particulate visualization. The article includes a discussion of psychologist Jean Piaget's theory of constructivism as applied to chemistry. Also presented are research methodology and results.

Abstract: The surface coverage of phosphorylated oligonucleotides immobilized on a zirconium-phosphonate surface was analyzed using X-ray photoelectron spectroscopy (XPS). By quantifying the intensity of the N 1s signal originating from the oligonucleotide and the Zr 3d peak from the metal-phosphonate surface, the surface coverage of the oligonucleotide could be calculated with a modified substrate-overlayer model. We found relatively low surface coverages indicating that once covalently bound via the terminal phosphate the polymer chain further physisorbs to the surface limiting the adsorption of additional molecules. [Copyright &y& Elsevier]

Terminal phosphate groups on double-stranded DNA probes bind strongly to glass substrates coated with a zirconium phosphonate monolayer, and probes immobilized in this way as microarrays can be used to detect protein targets. The sensitivity of the microarray was shown to be enhanced by the use of a polyguanine segment ((G)n, n ⩾ 5) as a spacer between the phosphate linker and the protein interaction domain. More importantly, the presence of phosphate linkers on both ends of the dsDNA probes leads to significant enhancement of target capture. The relevant characteristics of the different probes when bound to the surface were determined, by the original use of a combination of surface characterization techniques (XPS, AFM, and Sarfus). In this context, the location of the phosphate linkers in the duplex probes was found to result in different probe surface coverage and presentation on the surface, which affect subsequent interactions with the target protein. [ABSTRACT FROM AUTHOR]

Abstract: Films of the photomagnetic Prussian blue analogue Rb0.7Co4(Fe(CN)6)3.0(Co–Fe PBA) were deposited onto a Melinex® substrate using two different multiple sequential adsorption methods. Film thickness, measured using atomic force microscopy, was controlled by the number of deposition cycles. The photoinduced magnetism known for the bulk Co–Fe PBA at low temperatures is also seen in the thin films, although the response is anisotropic. A photoinduced increase in magnetization is observed when the film is parallel (∥) to the applied magnetic field (H E), while a photoinduced decrease is observed when the film is perpendicular (⊥) to a weak H E. The relationship between the film thickness and the photoinduced decrease in magnetization is explored in this article. The photoinduced decrease is observed for films less than ∼200nm thick. The behavior is explained by invoking a dipolar interaction between primordial ferrimagnetic domains and the photoswitchable pairs arrayed in the quasi-2D thin film. [Copyright &y& Elsevier]