Fight Duration Research Articles

Особливості змагальної діяльності на континентальних чемпіонатах 2023 року з греко-римської боротьби

Purpose: to determine the features of competitive activity at the 2023 continental championships in Greco-Roman wrestling. Material and methods. The analysis of scientific and methodical literature, the analysis of protocols and video recordings of competitive activities was used to solve the research tasks; expert assessment; methods of mathematical statistics. 105 matches at the 2023 continental championships were analyzed: Asian Championship (n=30 matches), European Championship (n=30 matches), Pan American Championship (n=24 matches), African Championship (n=21 matches). A total of 210 wrestlers (winners and losers), participants in the final fights (fighting for first and third places) took part in the study. In competitive activity, the following indicators were evaluated: the duration of fights (time of the fight); all technical and tactical actions carried out by wrestlers in fights (number of times); the number of non-standard situations in the rack and parterre (passives, violations of the rules, challenges); effectiveness of the applied technique in the rack and parterre (assessed in points: 1 point, 2 points, 4 points, 5 points). Results: the analysis of the fights made it possible to establish that at most continental championships, athletes performed more technical and tactical actions (TTD) in the rack than in the floor: European Championship (rack – 57,7 %; floor – 42,3 %); Asian Championship (stand – 59,8 %; floor – 40,2 %); African Championship (stand – 52,5%; floor – 47,5 %). At the Pan American Championship, athletes spent more TTD in the floor than in the rack (rack – 31,8 %; floor – 68,2 %). The highest average number of non-standard situations per scrimmage is observed at the European Championship (1,83 non-standard situation per scrimmage), then at the Asian Championship (1.80 non-standard situation per scrimmage), then at the Pan American Championship (0,92 non-standard situation per scrimmage) and African Championship (0,76 non-standard situation per scrum). The highest average performance in a scrimmage is observed at the Asian Championship (7,40 points per scrimmage), then at the European Championship (6,83 points), then at the African Championship (4,76 points) and at the Pan American Championship (4,50 points). Conclusions. An analysis of competitive activity at the 2023 continental championships in Greco-Roman wrestling was conducted. The results of the study indicate the peculiarities of each championship: a different ratio of technical and tactical actions in the racks and parterre; the difference in the average number of non-standard situations and performance in fights. The obtained results will make it possible to provide recommendations on changing the rules of competitions and increasing the spectacle of Greco-Roman wrestling.

A Review and Meta-Analysis of the Studies Conducted on the Impact of Micropollutants on the Aggressive Behaviors of Some Crustaceans

The aquatic environment is constantly polluted by point and non-point sources of contaminants, endangering animals. For example, micropollutants and heavy metals have been demonstrated to influence the physiology and behavior of crustaceans. Some research has reported that the aggressive behavior of crustaceans tends to change as an early warning sign of environmental contamination. A meta-analysis of the effects of micropollutants and heavy metals on crustaceans’ behavior. The results show that, for all investigated pollutant effects on fight duration across 18 datasets, the SMD range was -1.26 to 0.64 with a heterogeneity (Q) of 267.11 (p < 0.01), indicating high variability among studies. The publication bias p-value was 0.27, suggesting no significant publication bias for this endpoint. Specifically, for micropollutants affecting fight duration in 11 datasets, the SMD ranged from -1.41 to 1.02, with a heterogeneity (Q) of 182.82 (p < 0.01), again showing high variability. The publication bias p-value was 0.76, indicating no significant publication bias. Regarding the effects of all investigated pollutants on the number of fights in 10 datasets, the SMD ranged from -3.32 to -1.01, showing a statistically significant negative impact on aggressive interactions. The heterogeneity (Q) was 83.37 (p < 0.01), and the publication bias p-value was <0.01, indicating a significant publication bias for this endpoint. For micropollutants specifically affecting the number of fights in 7 datasets, the SMD ranged from -3.75 to -0.41, with a heterogeneity (Q) of 77.32 (p < 0.01) and a publication bias p-value of <0.01, again indicating a significant publication bias. When the size effect values and standard mean differences in confidence intervals of the different investigations were considered, the review revealed a high heterogeneity of published results and a tendency to find publication bias. The analysis concluded that aggressive behavior as an early warning sign for environmental contamination should be performed with caution because the levels required to trigger a response in some species are frequently insignificant regarding environmental relevance.

Experimental quantification of genetic and ontogenetic effects on fighting behavior in the broad-horned flour beetle

Most animal behaviors show large within- and among-individual variation, and this includes competitive male behaviors. With male fighting for example, aggressiveness often correlates with dominance, and contest duration varies with age. However, few studies have directly quantified how mean aggressiveness and contest duration, the variation among individuals in both traits, and the relationship among them, vary with age. Here we address these gaps and examine the effect of male age and genotype on two key aspects of male fighting behavior - aggressiveness (here measured as latency to fight) and contest duration - and the relationship between them. We do this using isogenic lines of the broad-horned flour beetle Gnatocerus cornutus. We observed fighting behavior of paired males of similar body size and age. Using uni- and multivariate mixed models, we show that although there was a significant difference between younger and older males in contest duration, mean aggressiveness was not affected by male age. However, the variation in aggression and fight duration varied with age, being greater in younger and older males respectively. Additionally, although there was a positive correlation between aggressiveness and contest duration in younger males, this relationship was not found in older males. Finally, the only significant genetic effect was for aggression in younger males. Our study shows that age differentially shapes key components of male fighting behavior as well as the relationship among them, highlighting the dynamic nature and context-dependence of fighting.

Acoustic Signals and Behavior of the Invasive Freshwater Crayfish Cherax destructor (Clark, 1936)

The study of acoustic signals in aquatic animals contributes to developing new monitoring systems based on passive acoustics and improves our knowledge of their behaviors and ecology. Here, the sounds produced by the invasive species crayfish Cherax destructor and their possible role in intraspecific interactions are analyzed. Synchronized acoustic and video monitoring systems were used in a tank to record acoustic signals and associated behavioral events (tail flips, number of encounters, number of fights) and states (velocity and distance moved, angular velocity, duration of fighting and proximity). The crayfish were monitored in seven layouts combining males (M) and females (F) (F, M, FF, MM, MF, MMF, FFM). Both males and females produced two types of acoustic signals (high- and low-frequency sounds). Grouped animals produced fewer low-frequency sounds than single animals. In a grouped layout, more sounds were recorded when animals were in proximity (distance between two specimen less than 6 cm). In a single layout, sounds were not associated with a specific event or behavioral state. The number of signals emitted in the FF group and single M group were significantly higher than those in other layouts. Our study indicates that low-frequency sounds are produced non-accidentally and provide a baseline for future tests on intraspecific acoustic communication on this species. This study could help implement low-cost passive acoustic monitoring able to identify this species and the possible negative effect of its dispersion in a non-native environment.

Catch‐and‐Release Angling Effects on Lake Sturgeon in Wisconsin, USA

AbstractDiscard mortality is an important factor to consider when managing catch‐and‐release fisheries. Even low levels of discard mortality can induce population‐level effects particularly in long‐lived, low‐productivity species like Lake Sturgeon Acipenser fulvescens. Unfortunately, little is known about the effects of catch‐and‐release angling on Lake Sturgeon physiology and probability of discard mortality. We used controlled angling events with standardized gear to capture 96 Lake Sturgeon from August to October 2019 from four regional locations in Wisconsin, USA. We evaluated the physiological effects of angling and activation of the stress response using whole blood concentrations of lactate and glucose as well as assessment of reflex impairment and postcapture monitoring of recovery time. Lactate levels were positively related to fight duration and the fight duration × total length interaction. Glucose level was related to the time a fish spent out of water postangling event. Water temperature had a positive effect on the probability of reflex impairment and the probability that a sturgeon required recovery time. The recovery duration was positively related to the amount of time that the fish was out of water. The movements of a subset of 15 individuals from one location were monitored using acoustic telemetry for approximately 2 weeks postangling. All individuals showed continuous up‐ and downstream movement during the postrelease monitoring period, and there was no evidence of mortality related to the angling events. Managers considering catch‐and‐release fisheries for Lake Sturgeon should consider population‐specific relative abundance and catch rates. They should exercise caution in scenarios when seasonal aggregations may lead populations to be susceptible to high catch rates, during times of elevated water temperatures, or the combination of these factors. The Lake Sturgeon in this study appeared to be robust to angling‐induced stress effects. Nevertheless, caution is still warranted, as low levels of discard mortality have the potential to influence low‐productivity species like Lake Sturgeon.

Temporary Retention in Cold Water Reduces Postrelease Behavioral Impairment in Angled Rainbow Trout

AbstractThe effectiveness of catch and release as a conservation practice assumes minimal impacts to released fish. In most cases, angling‐related stressors can be mitigated via changes to angler behavior that reduce fight duration, handling, and air exposure. In some cases, stressors may significantly impact the ability of fish to engage in normal swimming behavior upon release. In these scenarios, it may be beneficial for anglers to assist recovery or retain fish until they are adequately recovered. We investigated the effectiveness of two assisted‐recovery devices at facilitating behavioral recovery in angled Rainbow Trout Oncorhynchus mykiss: (1) retention in a flow box, or (2) retention in a water‐filled cooler. Additionally, we compared the effects of assisted recovery in surface water (24–27°C) or cool water pumped from the hypolimnion (17–19°C). From July to mid‐September 2020, 169 fish were angled from five stocked lakes at Kenauk Nature (Montebello, Quebec). Fish were air exposed for 30 s, for 15 s, or not at all (0 s) and were held in a flow box or a water‐filled cooler for 3 min, while fish in a control group were immediately released. Triaxial acceleration and temperature biologgers were temporarily fixed around the trunk of the fish with Velcro to observe postrelease swimming behavior for 10 min. Rainbow Trout that were held in assisted‐recovery devices regained equilibrium significantly more quickly than those that were immediately released, and fish that were held in 17–19°C water regained equilibrium the most rapidly. In fish that were air exposed for 30 s, individuals that were held in recovery devices exhibited greater swimming activity compared to those that were immediately released. Our study demonstrates that for Rainbow Trout, assisted‐recovery devices can reduce equilibrium impairment, especially when water in the recovery devices is significantly cooler than the relatively warm surface water temperature. Global water temperatures are expected to rise as a result of anthropogenic climate change, and best practices for angling should be adapted to reflect increased thermal stressors for many game fish species. Ensuring that fish are vigorous upon release is imperative for reducing postrelease mortality caused by predation or thermal stress.

Feeding strategy changes boldness and agonistic behaviour in the swimming crab ( Portunus trituberculatus )

Agonistic behaviours and cannibalism are key factors that restrict increases in the production of crab aquaculture. To explore the effects of feeding strategies on the boldness, agonistic behaviour and physiological response of swimming crab (Portunus trituberculatus), three treatment groups were established (feeding once a day:S0, every 3 days: S3 and every 6 days:S6). The intensity and duration of fighting, and agonistic behaviours were compared. The hepatosomatic index and the concentration of glycogen, glucose and lactate were also measured. The main results were as follows: (1) With an increase in time between feeding, boldness, duration and intensity of fighting increased first, then decreased, reaching a maximum in the S3 group, and this was significantly higher than in the S6 group. (2) Agonistic behaviour increased first and then decreased. The ‘move to’, ‘cheliped display’ and ‘contact behaviours’ of crabs in the S3 group were significantly higher than the S6 group; (3) Before fighting, with the increase in feeding time, the hepatosomatic index, glycogen and glucose concentration of crabs decreased, and these indicators were significantly higher in the S0 group than in the S6 group. (4) After fighting, the glucose and lactate concentrations were significantly greater than those before fighting. These results suggest that both boldness and feeding strategy can affect the agonistic behaviour of crab. Short-term reductions in food resources promoted inter-individual fighting, and bold individuals were more likely to win battles. However, a long-term decrease in food resources reduced fighting among individuals.

Effect of different amount of food and female resource on competitive strategy and agonistic behavior of swimming crab (Portunus trituberculatus)

Obtaining limited resources is an important motivator behind competition in animals. In pond cultures of swimming crabs (Portunus trituberculatus) common resources that cause conflict are food and mates. To explore the effects of different levels of food stimulus (clam extract; CG, control group: 0; LCH, little clam homogenate: 5 mL; ACH, abundant clam homogenate: 25 mL) and mate stimulus (female-conditioned water FCW; SW, seawater: 85 L seawater; LFW, low concentration FCW: 21 L FCW + 64 L seawater; HFW, high concentration FCW: 85 L FCW) on competitive strategies and agonistic behaviors of male crabs, we built an agonistic behavior recording system. We analyzed behavior, changes of oxygen consumption rate (OCR), and the concentrations of glycogen, glucose, and lactate in chelipeds and hemolymph after fighting. The main results revealed the following: (1) With increased perceived availability of food, the frequency of contact and key behaviors was significantly higher in the CG and LCH group than the ACH group. Fight duration in the LCH group was significantly longer than in the ACH group. The fight intensity and OCR of the LCH group were significantly higher than CG and ACH group. The concentration of lactate in hemolymph and glucose in chelipeds of the LCH group were significantly higher than the ACH group. The concentration of glycogen in cheliped muscle of the LCH and ACH group was significantly higher than the CG. (2) The increased concentration of FCW in the HFW group caused the duration of fights and the frequency of contact behaviors to be higher than in the SW group. In the HFW group the key behaviors occurred significantly more than in the SW and LFW groups. Fight intensity was also higher in the HFW group than the other two groups, and the LFW group had higher fight intensity than the SW group. The OCR of LFW and HFW groups were significantly higher than the SW group. The lactate concentrations in hemolymph and chelipeds in the LFW group were significantly higher than those in the SW and LFW groups. The glycogen concentrations in the chelipeds of the LFW and HFW groups were significantly higher than in the SW group. These results showed that the crabs adopt different competitive strategies, either to fight or yield, depending on type and availability of resources. These strategies are associated with costs such as physical risk and energy expenditure. In pond cultures of swimming crabs, increasing the density of food and isolating females from males during the breeding season may help to reduce appendage mutilation or death caused by fighting, thereby increasing aquaculture efficiency.

Physiological effects of catch-and-release angling on freshwater drum (Aplodinotus grunniens)

Many catch-and-release angling events involve air exposure and exhaustive exercise that elicit a physiological stress response, and depending on a variety of factors, delayed mortality is a possible outcome. There have been ample studies in this area, however, significant gaps exist in the literature for species that are targeted by more specialized anglers, such as freshwater drum (Aplodinotus grunniens). We quantified physiological and reflex responses in freshwater drum following angling, across seasons. Once a fish was on the line, the fight duration and time exposed to air were varied to account for differences in angler skill level (fight time range: 5 s to 2 min; air exposure range: 20 s to 3 min). Location and severity of injury were determined, blood biopsies were taken to quantify physiological stress, and reflex impairment was assessed. Thirty-one percent of fish captured were deeply hooked in the esophagus tissue. Freshwater drum experienced a disruption in homeostasis as blood glucose, plasma cortisol, and plasma lactate increased significantly from baseline values following angling. Additionally, seasonal differences were observed for blood glucose and plasma cortisol as higher values were observed in the summer when compared to the spring. The ‘orientation’ reflex was the most frequently impaired (29 % of fish lacked this reflex), but impairment did not differ seasonally. Because freshwater drum have the largest latitudinal range of any North American freshwater fish and are being targeted more frequently by anglers as of late, it is important to fill this knowledge gap regarding their responses to angling events to develop best practices for anglers to promote conservation. The wide distribution of freshwater drum may also make them a candidate model species for addressing the convergence between assessing the impacts of catch-and-release angling and other environmental issues facing freshwater fishes, such as climate change.

Differences of Duration of the Fight Depending on the Stage of the Judo Competition

The purpose of this study is to compare the time characteristics of introductory and final rounds of judo competitions. This study analyzed 656 male judo fights in National Championships of Uzbekistan which were held in 2018 and 2019. All competition rounds were divided as first and the second subsample. Results were processed at the level of descriptive statistics. Descriptive parameters were counted: Average Indicator (M), Standard Deviation (SD), Minimal (Min) and Maximal (Max) results. The normality of the distribution of findings was tested using the Kolomogorov-Smirnov test and the T-test for independent samples was applied. Data were processed using the IBM SPSS Statistics 20.00 statistical package. The research results show that judo fights last longer in the second phase of the competition. The difference in the duration of the judo fights is - 63.47 seconds, i.e. the fight in the second phase of the competition lasts significantly longer, about 1.03 minutes. The results indicate that in judo both anaerobic and aerobic exercises are essential to get high achieves. High endurance capacity plays a crucial role in last rounds of the competition. This investigation would help to improve competitive effectiveness judokas, results would be clear indication of how to energy expenditure in a various rounds of the competition. Time characteristics of each phases of the contests are directly connected with physiological bases of judo such as energy consumption, VO2 intake and Blood Lactate concentrations of the athletes during the different rounds.

Effects of the 2017/18 rule changes in fight duration, fight decisions, scores, penalties, and attempts in judo, based on systematic competition analysis of the World Championships 2015 and 2018

ABSTRACT The International Judo Federation (IJF) has changed the book of rules several times recently, with the last changes being implemented in 2018. Based on a systematic performance analysis, before and after the last rule changes, this research investigates how these changes have affected fight duration, fight decisions, scores, penalties, and attempts in judo. Data was collected from 308 judo fights of the World Championships 2015 in Astana and 2018 in Baku using video footage. Statistical analyses were performed in SPSS and consisted of descriptive statistics, paired T-tests and Wilcoxon tests, the effect sizes were calculated with Cohen`s d and r, respectively. The results show that the amount of fight decisions Ippon (Astana: 31.20%; Baku: 43.50%; p = .046; d = 0.59) and Wazaari-awasete-Ippon (Astana: 7.10%; Baku: 15.60%; p = .031; d = 0.65) increased, whereas the occurrence of Shido fight decisions decreased (Astana: 21.40%; Baku: 7.10%; p = .009; d = 0.50) at the 2018 World Championships, compared to 2015. No statistical differences were found between these two competitions regarding the number of attacks, attack frequencies, effectiveness and fight duration. Future research should investigate the differences between the weight categories, as well as further adjustments of judoka to the new rules.

Influence of toys on behavioural patterns of pigs and their association with the concentration of serotonin in blood plasma

Improvement of welfare of piglets is one of the key factors which underlie the effectiveness of producing pork and the profitability of pig farming. This article offers a solution to the main industrial problem – creation of comfortable maintenance conditions for pigs using toys which satisfy their ethological needs. Piglets used in the experiment were kept in the swine complex of agricultural production of Agrofirm Mig-Service-Agro Cooperative in Novoodesky district of Mykolaiv Oblast (Ukraine). The objective of the study was assessment of the effect of toys on the behaviour of piglets, level of concentration of hormone serotonin in blood plasma and their energy of growth. The experiment was performed on 120 weaned piglets aged 28 days, which were divided according to the principle of analogues with 60 individuals in each group: I – the control group, the animals were kept with no toys; II – the experimental group, where the animals had toys. During the experiment chronometric monitoring of the piglets’ behavioural acts was carried out using video observation, we extracted blood samples for determination of the content of the hormone serotonin using the method of highly-efficient fluid chromatography and assessed the growth of the piglets. After the end of the experiment, we determined that the presence of toys reduced the intragroup aggression, which was accompanied by decrease in the duration of fights and almost three-fold increase in playing behaviour. Among piglets which had access to toys, the number of individuals observed to bite tails and ears decreased from 11 to 3. In the period of the study, the concentration of serotonin in the blood plasma of piglets who had free access to toys was 10 times higher compared with animals of the control group. Change in the behaviour patterns among the animals of the experimental group led to significant differences regarding the parameters of growth, where probable increase in the live weight at the age of 90 days was observed, which was associated with significant increase in their mean daily weight gain compared with the animals of the control group. This study confirms that use of toys for piglets during growth completion can prevent features of aggression and abnormal forms of stereopathy within groups, increase the live weight and mean daily weight gain and improve emotional condition, which affects the welfare of pigs.

Analysis of direct and indirect genetic effects in fighting sea anemones.

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.

Longitudinal Analysis of Tactical Strategy in the Men's Division of the Ultimate Fighting Championship.

This study explored longitudinal changes in contemporary mixed martial arts (MMA) combat within the Ultimate Fighting Championship (UFC). A secondary aim was to investigate how bout duration influences the contribution of performance indicators on outcome. Data were acquired via the official analytics provider to the UFC (FightMetric). Male fights with a winner from between 2000 and 2015 (n = 2,831) were examined, with 13 common performance indicators attained during each round for each participant along with duration (min) and year of fight. Non-metric dimensional scaling (nMDS) was used to examine bout characteristics by year. The Repeated Incremental Pruning to Produce Error Reduction (RIPPER) algorithm was run to determine a set of rules to explain bout outcome. The nMDS displayed that winning bout performance indicator attributes were dissimilar across the years. Eight rules were generated from the RIPPER, with fight duration featuring in three of eight rules. Distinct shifts occurred (albeit without linear trend) in performance indicator characteristics during the observed period. This was characterized by a more diverse combat style in the years following 2008. However, offensive grappling has remained a key factor regardless of year, and is influenced by bout duration.

Stress, predators, and survival: Exploring permit (Trachinotus falcatus) catch-and-release fishing mortality in the Florida Keys

The biological consequences of catch-and-release (C&R) angling revolve around interactions between the physiological and behavioural responses of the captured fish and ecological conditions such as the presence of opportunistic predators. Here, we explored the consequences of C&R on adult permit (Trachinotus falcatus), including assessments of depredation rates, their physiological and reflex responses prior to release, post-release behaviour, and post-release predation in diverse habitats in the Florida Keys, USA. We found pre-capture depredation rates were highly variable amongst habitat types, ranging from zero on shallow water flats, to 35.3% and 90.1% on specific reef and shipwreck locations, respectively. Observed predators were all large sharks. Importantly, one of the high predation sites is an important permit spawning location, thus C&R fishing in that locale may be a conservation concern. Physiological stress responses (blood lactate, glucose, pH) and reflex tests indicated that permit were relatively robust to routine angling (fight durations of 1 to 12 min) and handling (air exposure up to 2 min). Short duration post-release tracking using tri-axial acceleration biologgers identified no differences in swimming activity for fish that were kept in water versus those held in the air for 2 min to simulate an admiration period. While this study indicates that permit are relatively robust to C&R angling in terms of stress responses and behavioural impairment, high densities of opportunistic predators at certain fishing locations can result in high rates of pre-capture depredation independent of the state of the animal. Permit angling in locations with high predator densities is a potential conservation issue, especially if specific locations represent important pre-spawning aggregation sites for fish populations that may be more vulnerable to predation and thus depredation. Current C&R best practices (i.e., limiting fight times and air exposure) may not be adequate to ensure permit survival at high predator density sites. Angling-related depredation is often cryptic, yet is a growing conservation concern in many fisheries – we developed and applied a novel framework for identifying cryptic depredation that may be applicable across fisheries.

The intensity and spectrum of artificial light at night alters crayfish interactions

ABSTRACTEcological light pollution (ELP) is quickly becoming a worldwide concern and can negatively affect aquatic ecosystems. The given intensity and spectrum of a light source can influence how organisms function within their environment. These properties of artificial lighting at night (ALAN) and their impacts on the physiology and behaviour of crayfish were examined in this work. Hemolymph was obtained from crayfish to quantify a physiological response. Behavioural data were measured as the number, duration, and maximum intensity of agonistic fights. Exposure to higher intensities of light and the presence of ultraviolet light induced a behavioural trend, resulting in significantly altered social interactions within both species of crayfish. The number and maximum intensity of lights significantly decreased, whereas the duration of time spent fighting significantly increased. Due to the importance of freshwater environments and the role crayfish play as a keystone species, examining how crayfish are impacted from ALAN is imperative to maintaining the health of aquatic ecosystems.

Advantages of social skills for contest resolution.

Animal contests are natural interactions that occur to obtain or defend resources such as food and territory. Selection should favour individuals that can win contests with minimal costs in terms of energy expenditure or injuries. We hypothesized that social skills contribute to animals' assessment abilities in a contest situation and thereby will shorten contest duration. Animals were either raised in early life conditions stimulating the development of social skills, termed socialization or not (control). Contests between 342 pigs at eight weeks old (171 dyads) were studied for opponent assessment ability (using a game theoretical approach), examining duration and escalation, social behaviours performed, injuries and outcome. Contesting dyads were from the same treatment group and varied in body weight, a validated measure of resource holding potential (RHP). Socialized animals had shorter contests that were resolved with fewer injuries and they showed more ritualized display behaviour, consistent with mutual assessment. Furthermore, there was evidence of a novel form of opponent assessment in the socialized group revealed by a positive relationship between winner RHP and fight duration. In conclusion, social skills enabled more rapid establishment of dominance relationships at lower cost. Besides its evolutionary relevance, these findings may also contribute towards improving animal welfare.

Fighting in rounds: males of a neotropical cricket switch assessment strategies during contests

How animals decide to withdraw from contests is central to understand the evolution of fighting behavior. Game theory models suggest 2 major types of decision criteria: 1) self-assessment, where individuals withdraw when they reach a cost-threshold determined by their own fighting ability that may or may not be affected by injuries, or 2) mutual assessment, where the decision is based on information about the relative fighting ability of the opponents. Many empirical studies have assumed that opponents use a single strategy throughout the whole fight. However, they often find partial support for a specific model. This might be due to individuals changing their strategy between phases of a contest. In this work, we addressed this issue by evaluating if males of the cricket Melanotes ornata switch their assessment strategy between phases. We used hind femur length as a proxy for fighting ability, as it was the attribute most strongly associated with contest outcome. Overall fight duration was positively associated with the loser’s femur length and negatively associated with the winner’s femur length, while the probability of escalation to physical aggression was negatively related to the difference in femur between opponents. However, such relationships held only at the first contest phase. During the escalated phase, fight duration was only correlated (although weakly) with femur length of losers. These results indicate that M. ornata males perform mutual assessment in the initial phase but switch their assessment strategy when fights escalate, suggesting a single strategy does not correctly explain how contests are settled.

Feeding Strategies Before and at Mixing: The Effect on Sow Aggression and Behavior.

Simple SummarySows in domestic settings are often mixed into new groups of animals, resulting in the need to form hierarchies, causing aggression and related stress. Restrictively fed gestating sows are unlikely to be sated, and are more likely to view food as a limited resource and to be frustrated and aggressive. Creating satiety in sows as they are mixed may be a simple method to reduce mixing aggression. This experiment assessed the provision of different diets; a standard diet (CON) or high (HI) volume of a “standard” diet, or a diet enhanced with lignocellulose (fiber source) fed before mixing (LC) and at mixing (LCM), was studied. There were treatment effects on fight duration, the number of fights, injuries, condition scores, and time spent eating and drinking. These results suggest that feeding a diet containing 2.5% lignocellulose and a standard diet at a high feeding level for four days post-mixing may affect overall aggression within groups and sow satiety levels. Our data found decreased fight numbers and increased fight duration in the LCM compared to the LC treatment, and therefore, feeding the fiber source before mixing affects aggression levels differently than when fed just after mixing. A further understanding of different fiber sources and how their properties affect digestion and sow satiety would enable critical evaluation and use of fiber sources for benefit in reducing aggression at mixing.Hierarchy formation in domestic sows results in aggression and stress, which might be ameliorated through nutritional satiety. The effect on aggression in group housed, gestating sows provided a standard or high volume of a “standard” diet, or diet enhanced with lignocellulose before, at, and after mixing was studied. Ninety-six Large White cross Landrace weaned sows were allocated to: control diet (CON), high volume diet (HI), and lignocellulose-enhanced diet before and at mixing (LC), and after mixing (LCM) (24 sows per treatment). Sows were housed in stalls for 10 days before mixing, when the CON, HI, and LCM groups were fed a standard diet, and in the LC group, a diet enhanced with lignocellulose at 2.5% was given. At mixing, the CON group continued on a standard diet at 2.5 kg/sow per day, HI were fed the standard diet at 4 kg/sow per day for the first four days and 2.5 kg/sow per day thereafter, and LC and LCM were fed the lignocellulose-enhanced diet at 2.5 kg/sow per day. Behavior, salivary cortisol concentrations, lesion number, and condition were recorded on M0, M1, M6, and M14. Reproduction was assessed using pregnancy rate and progesterone measurements. There were several treatment effects on aggression in the sows following mixing. There were significantly lower fight numbers (CON = 0.34 ± 0.03 Log (1 + x) transformed mean and SEM (1.49 untransformed adjusted mean), LC = 0.31 ± 0.04 (1.14), LCM = 0.42 ± 0.04 (0.28), HI = 0.35 ± 0.04 (1.64); p = 0.001) and longer individual fight durations in the LCM group compared to the CON and LC group (CON = 0.88 s ± 0.07 Log transformed mean and SEM (10.31 s, untransformed adjusted mean), LC = 0.89 ± 0.09 (13.51), LCM = 1.16 ± 0.07 (21.43), HI = 01.03 ± 0.07 (16.42); p = 0.04), and overall higher injury numbers in the LC and LCM groups than the HI. Time spent eating was significantly lower in the CON group than both HI and LC (CON = 7.79 ± 0.37, LC = 8.91 ± 0.38, LCM = 8.49 ± 0.42, HI = 9.55 ± 0.39; p = 0.007). The time spent drinking was also affected by treatment, with more time spent drinking in CON than LC (p = 0.024). The condition score of the sows was affected by diet, with higher condition scores in the HI group than LCM and LC (CON = 2.98 ± 0.11, LC = 2.75 ± 0.10, LCM = 2.74 ± 0.10, HI = 3.12 ± 0.10; p = 0.017). These results suggest that feeding a diet containing 2.5% lignocellulose and a standard diet at a high feeding level for four days post-mixing may affect overall aggression and possibly satiety levels. Our data found decreased fight numbers and increased fight duration in the LCM compared to the LC treatment, and therefore, feeding the fiber source before mixing affects aggression levels differently than when fed just after mixing. A further understanding of different fiber sources and how their physiochemical properties affect digestion and sow satiety would enable critical evaluation and use of fiber sources for benefits in reducing aggression at mixing.

Group lactation from 7 or 14 days of age reduces piglet aggression at weaning compared to farrowing crate housing

Early life experiences can affect social behaviour in later life, but opportunities for socio-behavioural development are often overlooked in current husbandry practices. This experiment investigated the effects of rearing piglets in two-stage group lactation (GL) system from 7 or 14 days of age on piglet aggression at weaning. Three lactation housing treatments were applied to a total of 198 piglets from 30 litters of multiparous sows. All dams farrowed in standard farrowing crates (FCs). Group lactation litters were transferred with their dam at 7 (GL7) or 14 days (GL14) postpartum to GL pens (one pen of five sows at 8.4 m2/sow and one pen of seven sows at 8.1 m2/sow, per GL treatment). Farrowing crate litters remained with their dam in a single litter until weaning. At weaning, 10 to 14 piglets from two unfamiliar litters from the same housing treatment were mixed into pens (n=5 pens/treatment) and their behaviour was continuously recorded for 3.5 h. For each pen, the frequency of aggressive bouts (reciprocal and non-reciprocal aggression lasting <5 s), the frequency and duration of fights (reciprocal aggression lasting ⩾5 s) and bullying events (non-reciprocal aggression lasting ⩾5 s) were recorded, along with whether interactions involved familiar or unfamiliar piglets. Aggressive bouts delivered by FC piglets were approximately 1.5 and 3.0 times more frequent than that delivered by GL7 and GL14 piglets, respectively (40.5, 16.7 and 9.9 bouts/pig, respectively; P<0.05). Fighting was more frequent (1.6, 0.3 and 0.4 fights/pig, respectively; P<0.001) and fights were longer (83, 15 and 32 s fight/pig, respectively; P<0.001) between FC piglets than between GL7 or GL14 piglets. Bullying did not differ between housing treatments (P>0.05). GL7 and GL14 piglets engaged in a similar number of fights with unfamiliar as familiar piglets, but FC piglets had almost three times as many fights with unfamiliar than with familiar piglets (P<0.05). This experiment confirms the benefits of GL housing for pig social development. Further investigation is required to determine whether mixing before 14 days postpartum has implications for other indicators of animal welfare and productivity in a two-stage GL housing system.