Agonistic Behavior Research Papers - Academia.edu (original) (raw)

2025, Physiology & Behavior

In young black-headed gulls (Larus ridibundus), exposure to testosterone increases the sensitivity of agonistic behaviour to a subsequent exposure to this hormone. The aim of this paper is twofold: to analyze whether social experience, gained during testosterone exposure, mediates this increase in hormonal sensitivity (priming), and whether this in turn is mediated by an increase in central aromatase activity. To this end, we performed three experiments. In the first juvenile gulls were exposed to two consecutive treatments with testosterone (T1 and T2), with more than a week interval in between. During T1, half of the birds were housed in social isolation (Iso) and the other half in groups (Soc). All birds were re-housed in a new social situation during the second treatment. The increase in social behaviour during T2 was significantly more rapid in Soc than Iso birds. In experiment 2 we show that 17β-estradiol treatment facilitates the behaviour measured in experiment 1. In experiment 3 we used a set-up comparable with that of experiment 1, but birds were sacrificed early in the T2 period. Aromatase activity in the preoptic area and the hypothalamus was measured using the tritiated water releasing method. In some parts of the preoptic area and hypothalamus aromatase activity was higher in Soc birds relative to Iso birds. The results indicate that social experience can modulate the increase of social behaviour to testosterone via modulation of aromatase activity and independently of actual hormone levels.

2025, Bioorganic & Medicinal Chemistry

We report the synthesis, binding properties and intrinsic activity at MT 1 and MT 2 melatonin receptors of new dimeric melatonin receptor ligands in which two units of the monomeric agonist... more

We report the synthesis, binding properties and intrinsic activity at MT 1 and MT 2 melatonin receptors of new dimeric melatonin receptor ligands in which two units of the monomeric agonist N-{2-[(3-methoxyphenyl)methylamino]ethyl}acetamide (1) are linked together through different anchor points. Dimerization of compound 1 through the methoxy substituent leads to a substantial improvement in selectivity for the MT 1 receptor, and to a partial agonist behavior. Compound 3a, with a trimethylene linker, was the most selective for the MT 1 subtype (112-fold selectivity) and compound 3d, characterized by a hexamethylene spacer, had the highest MT 1 binding affinity (pK iMT1 = 8.47) and 54-fold MT 1 -selectivity. Dimerization through the aniline nitrogen of 1 abolished MT 1 selectivity, leading to compounds with either a full agonist or an antagonist behavior depending on the nature of the linker.

2025, Behavioural Brain Research

Zebrafish which carries a mutation in the fibroblast growth factor receptor 1A (fgfr1a), also known as spiegeldanio (spd), has previously been reported to be bolder and more aggressive than wildtype (AB) zebrafish. However, in previous studies aggression has been quantified in mirror tests. In dyadic fights the behavior of the combatants is modified by the behavior of their opponent, and fighting a mirror has been reported to have different effects on brain gene expression and brain monoaminergic systems. In the present study aggression was quantified in fgfr1a mutants and AB zebrafish using a mirror test after which the fish were allowed to interact in pairs, either consisting of two fgfr1a mutants or one AB and one fgfr1a mutant fish. Following dyadic interaction aggressive behavior was again quantified in individual fish in a second mirror test after which the fish were sacrificed and brain tissue analyzed for monoamines and monoamine metabolites. The results confirm that fgfr1a mutants are more aggressive than AB zebrafish in mirror tests. However, fgfr1a mutant fish did not have any advantage in fights for social dominance, and agonistic behavior of fgfr1a mutants did not differ from that of AB fish during dyadic interactions. Moreover, as the AB fish, fgfr1a mutant fish losing dyadic interactions showed a typical loser effect and social subordination resulted in an activation of the brain serotonergic system in fgfr1a mutants as well as in AB fish. Overall the effects of dyadic interaction were similar in fgfr1a mutant fish and zebrafish of the AB strain.

2025, Behavioural processes

Relatedness is considered an important factor in shaping social structure as the association among kin might facilitate cooperation via inclusive fitness benefits. We addressed here the influence of relatedness on the social structure of a Neotropical ungulate, the collared peccary (Pecari tajacu). As peccaries are highly social and cooperative, live in stable cohesive herds and show certain degree of female philopatry and high mean relatedness within herds, we hypothesized that kin would be spatially closer and display more amicable and less agonistic interactions than non-kin. We recorded spatial association patterns and rates of interactions of two captive groups. Pairwise relatedness was calculated based on microsatellite data. As predicted, we found that kin were spatially closer than non-kin, which suggests that relatedness is a good predictor of spatial association in peccaries. However, relatedness did not predict the rates of social interactions. Although our results indire...

2025, Ethology Ecology & Evolution

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2025

Bearded Vultures Gypaetus barbatus began supplying material to their nests on average 111 d (range 91-126 d) prior to laying . Males were signifr icantly more active that females. Heavy material (branches) was transported indistinctly in the talons or in the bill while lining (wool) was generally transported in the bill . 71% of the wool was recycled from remains fallen ; from other nests, probably due to the scarcity of this material in relation to its importance for insulating the egg and chick from the low winter temperatures . No inter-sexual differences were observed with regard to the type of the material selected or how it was carried to the nest . The early nest-building behaviour and the fact that the males were the most active builders are discussed in the context of maintenance of the pair-bond and female selec-~;~ tion. After laying, material for nest-maintenance was only rarely supplied, suggesting high solidity of the structure at its location at protected sites .

2025, Bulletin of the Psychonomic Society

The 2-deoxyglucose method was used to compare regional brain activities of unrestrained wild Norway rats engaged in fear-based defensive behavior (n = 81, and that of solitary controls (n = 81. After infusion with 100 micrograms/kg of ('4CI-deoxyglucose via jugular catheters, experimental rats spent the 45-min uptake period in flight, boxing, and defensive attack to painless threat stimuli. Coronal sections of brains were exposed to X-ray film, and the resultant global maps of regional brain activity for the two groups were quantitated by high-resolution fiber optic densitometry at 86 cerebral points and analyzed statistically by computer. Significant group differences in regional brain glucose uptake were found at 16 loci. The considerable agreement between these structures and those previously identified in the literature as involved in defensive behavior provides evidence for the potential of this method of investigation of brain correlates of specific behavioral patterns. Until fairly recently, brain energy metabolism in vivo was studied primarily by way of the nitrous oxide technique of , which measures average rates of energy metabolism for the brain as a whole, It was found that overall cerebral metabolic rates were constant for a number of conditions, including deep sleep, performance of mental arithmetic, schizophrenia, drug-induced sedation, tranquilization, and psychosis, It varied only with structural or functional alterations, such as occur in postnatal development, senility, anesthesia, and convulsive states (Kety, 1950; Lassen, 1959;. However, newer developments have made possible the resolution of regional cerebral energy metabolism.

2025

Widely distributed species are exposed to different environmental forces throughout their range. As a response to differences in local environmental conditions, these species are expected to present geographic variation in phenotypic traits (e.g., behavioral, physiological, anatomical) in order to better adapt to these conditions. Parawixia bistriata (Araneidae) is a colonial spider distributed in a variety of habitats in South America. This species is unusual in two respects: contrary to most social species found in tropical wet forests, P. bistriata's distribution extends from tropical to temperate latitudes; and it exhibits facultative group foraging, a behavioral pattern absent in territorial colonial spiders. In this dissertation, I examined the existence of geographic variation in life history and behavioral traits of P. bistriata's populations inhabiting sites with distinctive environmental conditions and estimated success of populations. I performed reciprocal transp...

2025, Primates

We studied the social and foraging behavior of two captive groups of sooty mangabeys under two different spatial food situations. These food conditions were clumped (food was placed in a box) and dispersed (food was dispersed over the entire enclosure). In each group five adult females and two adult males were observed. As a criterion for food competition, individual differences in the relative food intake were used. Adult female mangabeys had a linear, stable, and unidirectional dominance hierarchy. Access to food was rank dependent among females only under clumped food distribution, as current models of the evolution of primate social systems predict. However, feeding success appeared to be mediated not by female but by male agonistic behavior toward females. High-ranking females received relatively less aggression from males and could, therefore, stay and feed longer in the feeding area. Male tolerance of higher-ranking females seems to mediate female feeding success under restricted food resources. The establishment of a special relationship with a high-ranking male might, therefore, be a strategy to get better access to food. This study demonstrates that female competition for access to food should not be analyzed separately from male influences on females and suggests that a more integral role of males in socioecological models of the evolution of primate social systems should be considered.

2025, Aggressive Behavior

Fighting between males is a frequent component of the rutting behavior of Cervidae. Frequent conflicts are exhausting; fighting may be risky and can lead to serious injuries or even death. We focused on the process of assessment of the opponent's fighting ability and escalation of the combat, estimating the probability of fighting based on the encounter components such as groaning and parallel walk. In this study, we observed the agonistic behavior of fallow deer bucks (Dama dama) during the rut over four seasons. During this time, we recorded 205 encounters between bucks. Non-contact display, which allows contestants to assess their opponents fighting ability, occurred in 83% of the encounters. The highest predicted probability of a fight was found when both of the males vocalized and turned into the parallel walk. The chance of a clear outcome decreased when the males were fighting in comparison to when they did not fight. The initiator of the competitive encounter won 41% of the cases, while the attacked buck won 23% of the encounters. If the contestants avoided fighting, however, the initiator won 78% of encounters. Therefore, the initiator was more successful when no fight occurred compared to when the encounters escalated into fighting. In most cases where ritualized behavior occurred, one of the opponents left after vocalization or parallel walk occurred. Thus, vocalization and parallel walk increased the probability for a clear outcome. The probability of a fight was lowest in situations where the males displayed asymmetric behavior. Increased symmetry of the contestants' behavior was strongly correlated with a higher probability of a fight. Thus, these results indicate that fallow deer bucks use efficient tactic during the rut, which, in turn, minimizes the chance of injury while fighting during the breeding season.

2025, Folia Zool

Lek is a territorial mating strategy which is widely spread amongst males in the fallow deer, Dama dama high density population. A group of fallow deer in Březka park, Czech Republic, was studied where males exhibit a mixed mating system with territorial (single temporary stands, leks) and non-territorial strategies during the rut. Reproductive success was estimated indirectly by counting females/minute held per male both on the lek and single temporary stands. A total of 636 records were analysed (281 on leks and 355 on temporary stands). In contrast to other reports, males on leks were accompanied with significantly less females (LSMEANs ± S.E., 3.80 ± 1.10 does present per minute of observation) compared to those on single temporary stands (6.74 ± 1.10 does present per minute of observation). The results suggest that under specific conditions (over-abundance of adult males compared to females) attracting females on the lek need not be the most effective one.

2025

In the past several decades there has been a proliferation of interest and development of family systems theories. A unique aspect of a systems perspective is that human problems develop in and because of social interactions usually within the family, rather than solely from some internal process within an individual. A second innovation is the view that human behavior always occurs in a context, and that understanding the context is essential for understanding problem development and resolution. The empirical evaluation and validation of these perspectives has lagged behind theoretical and therapeutic developments. Further, research in this area has been hampered by a lack of reliable and valid measures of constructs of interest. During the 1980s there were significant developments concerning measurement issues and instrument development that facilitate the assessment of family relationships. This chapter will review and discuss issues and methods for assessing family health and distress.

2025, Behaviour

The agonistic behaviour of the freshwater prawn, Macrobrachium rosenbergii, was studied in the laboratory. One hour long contests were conducted between prawns matched to size in each of the three sexually mature male morphotypes of this species; Small Males, Orange Clawed males and Blue Clawed males. An agonistic ethogram was established, consisting of 18 different acts. These acts were classified into indicators of dominance or subordinance following the application of cluster analysis. Prawns contests consisted usually of 3 phases: pre-escalated fighting phase, escalated fighting phase and post-escalated fighting phase. Contest phases differed both in the frequency of several acts and in the distribution of acts between the eventual winner and loser. In addition, the relative orientation and elevation of the opponents changed across phases. The inter and intra-individual sequences of acts of the winner and loser during the escalated fight were studied. Despite the similarity foun...

2025

The mice used in animal facilities belong to the family Muridae, subfamily Murinae, order Rodentia, genus Mus and species Mus musculus. They are social and territorial animals. Several lineages developed in the laboratory show aggressive behavior similar to that of wild mice. The aim of this study was characterize the hierarchical structure, body characteristics and hormonal levels in dominant, subordinate and non-aggressive mice. The model established for spontaneous aggression (MSA) evaluates the pattern of aggressive behavior (PBA) and categorizes the animals as follows: LAg -individuals with low aggressive behavior, HAg -dominant (highly aggressive) and Sb -subordinate. The regrouping of adult male mice produces substantial stress and influences the formation of their hierarchical structure. Behavioral comparisons before regrouping (BfR) and after regrouping showed that the percentage of body weight lost in mice was dependent of the specific categories as follows: LAg -68.1%, HAg -86.9% and Sb -90.5%; the average corticosterone levels by category were BfR: 43.5±17.5, LAg: 177.0±40.4, HAg: 72.8±23.8 and Sb: 136.4±51.2 ng/mL. Dominant mice showed differences in body characteristics (primarily the body/tail relationship) relative to subordinate mice. Two additional hierarchical positions were observed: "neutral individual" (without aggressive behavior) and "subordinate target" (an animal that receives approximately 30% of the total number of attacks made by dominant animals).

2025, Journal of the Autonomic Nervous System

The present study was performed on conscious, chronically instrumented dogs, which underwent selective blockade of sympathetic adrenergic and vagal outflows. Excitements were performed on these animals in normal states (N), after chronic treatment with guanethidine, for sympathetic blockade (SB), after cold vagal blockade (VB), and after combined sympathetic and vagal blockade (SB + VB). Heart rate and arterial blood pressure were monitored in all the experiments, while a group of dogs was also tested with an electromagnetic fiowmeter on the superior mesenteric artery. The role of the sympathetic and parasympathetic controls in the defencc reaction was assumed from comparison of experiments performed in the presence or in the absence of each (or both) autonomic component(s). In the SB + VB condition. excitement was followed by sudden hypotension, without changes in heart rate. In VB experiments, a brief and transient hypotension appeared, followed by gradually developed hypertension, while heart rate progressively rose in about 5 s; there was no sudden increase in mesenteric vascular resistance, which contrasted with the very marked reaction in N experiments. Under vagal control alone (SB), the stimulus * In memory of Prof. Lino Granata, who first initiated this experimental work.

2025, PloS one

Despite high estimates of the heritability of aggressiveness, the genetic basis for individual differences in aggression remains unclear. Previously, we showed that the wild-derived mouse strain MSM/Ms (MSM) exhibits highly aggressive behaviors, and identified chromosome 15 (Chr 15) as the location of one of the genetic factors behind this escalated aggression by using a panel of consomic strains of MSM in a C57BL/6J (B6) background. To understand the genetic effect of Chr 15 derived from MSM in detail, this study examined the aggressive behavior of a Chr 15 consomic strain towards different types of opponent. Our results showed that both resident and intruder animals had to have the same MSM Chr 15 genotype in order for attack bites to increase and attack latency to be reduced, whereas there was an intruder effect of MSM Chr 15 on tail rattle behavior. To narrow down the region that contains the genetic loci involved in the aggression-eliciting effects on Chr 15, we established a p...

2025

Résu m é : Lors de l'exploitation de sources sucrées de grande taille, M. sabuleti pratique une récolte collective basée sur l'utilisation d'un recrutem ent de m asse. Au niveau global, l'exploitation de deux sources de saccharose est, en général, de type asym étrique : l'activité de la colonie se concentre sur une des deux sources, l'autre étant sous-exploitée. Le com portem ent collectif de M. sabuleti présente néanm oins une certaine flexibilité : si une source 0,5M est découverte avant une source IM, les colonies restent prisonièrcs de leur premier choix; par contre, si une source 0,1M est découverte avant une source IM, les sociétés déplacent rapidem ent leur activité vers la source riche. L'interprétation de nos résultats fait appel à un modèle mathématique sim ple capable de simuler les situations de choix testées. Par ailleurs, nos résultats sont comparés à ceux obtenus sur deux autres espèces étudiées dans des conditions expérim entales comparables. Mots-clés : For micidae, My r mica sabuleti, r ec r utement alimentai r e, décisions collectives, modélisation mathématique. Summary : From food re cruitme nt to colle ctive décisions : tiie case of My r mica sabuleti. When exploiting large sugar sources, the colonies of M. sabuleti use mass recruitment. At the Society level, the exploitation of 2 sources of sucrose is generally asymmetrical : the activity of the colony concentrâtes on one source, the other being underexploited. Nevertheless, the collective behaviour of M. sabuleti shows a certain degree of flexibility : if a 0,5M source is discovered before a IM source, the colonies stay with their first choice. By contrast, if a 0,1M source is discovered before a IM source, the societies rapidly shift their activity towards the richer source. The interprétation of our results is based upon a sim ple m athem atical m odel which sim ulâtes the tested choice situations. In addition, our results are com pared to others obtained using two other species studied under comparable expérimental conditions.

2025, Journal of experimental psychology

2025, Journal of Experimental Psychology: Animal Behavior Processes

2025, Physiology & Behavior

2025, Environmental Entomology

2025, Behavioural Processes

Discovering a food source may invoke either competition or cooperation, depending on many factors such as divisibility and accessibility. We experimentally investigated the influence of effort to procure food on the tolerance towards others during feeding. Nine sub-adult captive ravens were tested in different foraging contexts that differed in foraging effort, namely three stringpulling conditions and two without pulling requirement. We expected that the effort to gain access to food would positively affect the tolerance towards others at feeding. As predicted, we found fewer agonistic interactions, fewer displacements of subordinates from food and prolonged feeding bouts in the three string-pulling conditions compared to the two conditions when no pulling was involved. Further, in the string pulling tasks interactions occurred mostly on the perch before pulling and only rarely was pulling interrupted by agonistic interactions. The rate of interactions did not change over trials. Our data suggests that perceived effort influences social behaviour.

2025, Behavioural Processes

In birds, the link between parental care behaviour and prolactin release during incubation persists after hatching in altricial birds, but has never been precisely studied during the whole rearing period in precocial species, such as ducks. The present study aims to understand how changes in parental care after hatching are related to circulating prolactin levels in mallard hens rearing ducklings. Blood was sampled in hens over at least 13 post-hatching weeks and the behaviour of the hens and the ducklings was recorded daily until fledging. Contacts between hens and the ducklings, leadership of the ducklings and gathering of them steadily decreased over post-hatching time. Conversely, resting, preening and agonistic behaviour of hens towards ducklings increased. Plasma prolactin concentrations remained at high levels after hatching and then fell after week 6 when body mass and structural size of the young were close to those of the hen. Parental care behaviour declined linearly with brood age, showed a disruption of the hen-brood bond at week 6 post-hatching and was related to prolactin concentration according to a sigmoid function. Our results suggest that a definite threshold in circulating prolactin is necessary to promote and/or to maintain

2025, Behavioral Ecology and Sociobiology

Behavioral interactions with native species may influence the invasiveness of introduced species. The salamanders Plethodon glutinosus and P. jordani in the eastern United States share many life history traits and demonstrate complex interspecific interactions that range geographically from competitive exclusion to sympatry. P. jordani was introduced to Mountain Lake Biological Station, Virginia, USA, between the years 1935 and 1945. We tested whether competition for space may influence the invasion of P. jordani into native P. glutinosus habitat by utilizing data from natural distributions, a field experiment, and controlled laboratory experiments. No environmental variables differed where P. glutinosus and P. jordani were collected in the field at the site of P. jordani introduction. In the field experiment, P. glutinosus was more fully exposed during foraging bouts in cages shared with heterospecifics as opposed to ones shared with conspecific salamanders. Condition (mass relative to body length) of salamanders at the end of the 3 months did not differ between conspecific and heterospecific treatments. In the laboratory, P. glutinosus most often attained the single burrow in the arena, but residency status had no effect. Species cohabited the burrow 50% of the time. Pair-wise encounters in the laboratory indicated that both species spend less than 20% of the time in aggressive behaviors as juveniles. Adults showed no behavior interpreted by us as aggression during pair-wise encounters.

2025, Sociobiology

Weaver ants are one of the most remarkable examples of social cooperation in nature. However, there are few studies to date on the particular aspects of their social behavior. In this study, we describe the behavioral repertory of Camponotus (Myrmobrachys) senex , a Neotropical weaver ant. A colony collected in the field was transferred to the laboratory for elaboration of an ethogram. Part of the colony: 20 wingless queens, 176 workers, 7 pupae, 30 larvae and 667 eggs, was conditioned in test tubes and put into two plastic boxes. One box was designated as nesting area and the other as foraging area. Both boxes were connected to each other. The ethogram was based on 20 hours of qualitative observations, followed by 50 hours of quantitative behavioral observations, "all occurrence sample" method (sensu Altmann 1974). We identified 58 different behaviors (30,651 registers), distributed in 10 behavioral categories. The most frequent categories were: immobility (0.4031%), grooming (0.1393%), exploration (0.1306%) and brood care (0.1035%). Immobility was the most frequent category in all castes and we suggest that immobility might be an energy saving strategy in C. senex. Workers displayed a more diversified behavioral repertoire with 57 different acts whereas, queens displayed 34 different acts. The use of male larvae by weaving nests can suggest an additional function for males, in addition to their usual sexual role. It is hoped that new taxonomic and behavioral studies will be carried out in order to obtain a better understanding of labor division in C. senex. Our results provide baseline data for future comparisons about evolutionary patterns in nest building behavior in ants as well as to the study of the genus Camponotus as a whole.

2025

A free-ranging bushbuck (Tragelaphus scriptus) population was observed over a period of 3 years, thereby enabling a detailed description of the behavioural repertoire of this widespread but barely investigated solitary African antelope species. Agonistic and submissive behaviour patterns are described, among them several hitherto un-described behaviour patterns -such as "escorting", where territorial males guide intruders to the periphery of their territory -and "push-up position", an extreme form of submissive behaviour. Furthermore, we report on behaviour patterns of males and females during mating as well as on behaviour patterns of parents directed towards their offspring. Again, we describe a hitherto unknown behaviour: the protection of calves by adult males, which may be a socio-positive behaviour directed towards their offspring led by kin selection.

2025, Journal of Ethology

2025, Critical Questions in Education

Public school teachers in Southwest Texas were surveyed regarding important civil behaviors students should practice and prevalent uncivil behaviors they have observed in the classroom. There was consensus across all demographic groups that the most important civil behaviors were the ability to successfully manage conflicts with others and the ability to respond respectfully to the opinions of others. The most prevalent uncivil behavior reported by the teachers was the use of sarcastic remarks to others followed by blaming others for their own negative actions. Focus groups with high school students were held on the same topic. Findings demonstrated similarities and differences between teachers and students and their perceptions of civility.

2025, PloS one

Mimesis is a relatively widespread phenomenon among reef fish, but the ontogenetic processes relevant for mimetic associations in fish are still poorly understood. In the present study, the allometric growth of two allopatric leaf-mimetic species of ephippid fishes, Chaetodipterus faber from the Atlantic and Platax orbicularis from the Indo-Pacific, was analyzed using ten morphological variables. The development of fins was considered owing to the importance of these structures for mimetic behaviors during early life stages. Despite the anatomical and behavioral similarities in both juvenile and adult stages, C. faber and P. orbicularis showed distinct patterns of growth. The overall shape of C. faber transforms from a rounded-shape in mimetic juveniles to a lengthened profile in adults, while in P. orbicularis, juveniles present an oblong profile including dorsal and anal fins, with relative fin size diminishing while the overall profile grows rounder in adults. Although the two sp...

2025, IJASS JOURNAL

A model dog bite prevention program was assessed for its ability to improve fourth grade students’ knowledge of factors known to influence safety around dogs. Students in an urban elementary school participated in either a program which focused on bite prevention or a program which focused on knowledge of the characteristics and history of common dog breeds. Both before and after participating in their respective program, students completed an instrument which measured knowledge of safety around dogs. Results indicate that students who participated in the bite prevention program knew more about safety around dogs after participation (a) than they themselves knew before participating in the program and (b) than did students know who had not participated in the dog breed program but instead participated in the other dog-related program. Future studies can assess the ability of bite prevention programs to reduce not only students’ knowledge, but also to prevent actual bites

2024, Journal of Fish Biology

Fourteen individuals of the skunk clownfish Amphiprion akallopisos of different sizes and of different sexual status (non-breeder, male or female) were analysed for four acoustic features. Dominant frequency and pulse duration were highly correlated with standard length (r = 0•97), and were not related to sex. Both the dominant frequency and pulse duration were signals conveying information related to the size of the emitter, which implies that these sound characteristics could be useful in assessing size of conspecifics.

2024, Lab Report (Agonistic Behaviour in Betta Splenden)

2024, Psychoneuroendocrinology

To study the effects of electroconvulsive therapy (ECT) on hormone release, we measured circulating concentrations of adrenocorticotropic hormone (ACTH), prolactin (PRL), growth hormone (GH) and cortisol (CORT) immediately before and at 2 min, 5 min, 15 min, and 30 min following ECT. Compared to pre-ECT concentrations, there were significant increases in post-ECT plasma ACTH, PRL and CORT. GH did not change consistently. No significant difference between unilateral and bilateral ECT was observed. Compared to the first ECT, repeated treatments were associated with a significant decrease in the magnitude of hormone surge. These hormonal changes induced by ECT may reflect changes at the neurotransmitter level.

2024, Oikos

A particular case and a general pattern: hyperaggressive behaviour by one species may mediate avifaunal decreases in fragmented Australian forests.-Oikos 101: 602-614. We quantitatively assessed edge effects associated with elevated abundance of a hyper aggressive bird species, the noisy miner Manorina melanocephala, in fragmented eucalypt forest adjoining developed land. Long-term data from Toohey Forest, subtropical Australia, show that noisy miner colonies intensively occupy a zone of 20 m from the forest edge, with frequent use occurring up to 100 m from the edge, but little beyond 200 m. Within noisy miner colonies, the abundance and species richness of other birds were both about half those recorded at nearby transects which were outside the colonies' main activity area. Bird species smaller than noisy miners, which are also those with similar diets, were collectively 20-25 times more abundant, and their species richness tenfold greater, outside miner colonies than within them, whereas larger species, which have less dietary overlap, did not differ. Exclusion of small insectivorous birds has been hypothesised to cause elevated insect herbivore density, but we found no difference between tree crown defoliation or dieback rates within versus outside miner colonies. Aggression by noisy miners can be viewed as a mechanism of interspecific competition, since miners have a relatively large body size for their diet and are hence able to exclude virtually all potential competitors at relatively little cost. We examine evidence indicating that reduced bird diversity in eucalypt forest fragments of eastern Australia is often simply the effect of noisy miner occupancy of edges, acting directly on the densities of other species through their aggressive behaviour. With an edge effect 200 m deep, a remnant 10 ha in size is likely to become entirely occupied by noisy miners, and this is a size threshold that has been commonly reported in association with area-standardised avian diversity reductions. Convergent patterns of species loss from small forest fragments in different continents are the result of different underlying ecological processes.

2024, Scientific American

T he waters of Lake Tanganyika are clear, dark and deep, but the shallow, sunlit edges are where most of the cichlids live. Brown or green Eretmodus algae scrapers, covered with blue spots, thrive among the breaking waves; the turbulent water pushes their rounded backs onto the rock surfaces instead of pulling them off. These fish nip algae off the rocks with their chisel-like teeth. Their neighbors the Tanganicodus insect pickers also have round backs. But the pointed heads, sharp snouts and long, fine teeth of these cichlids are adapted to plucking insect larvae from within the crevices. In calmer waters, old snail shells are strewn on 64 Female Haplotaxodon tricoti broods her young Color morphs of Tropheus duboisi live in separate rock piles Cichlids of the Rift Lakes The extraordinary diversity of cichlid fishes challenges entrenched ideas of how quickly new species can arise

2024

assistance in the field and help with scoring the many hours of videotaped snake behavior. This work was carried out with the support of an Oklahoma State Regents for Higher Education dissertation improvement grant and a doctoral scholarship from the Southern Region Education Board. I thank my parents, Ron and Connie Shipman, for their moral support and encouragement. Most of all, I thank my wife Lori for being by my side and for her patience and support, and my children, Alexandra and Alan for the joy that they bring me and for helping to remind me of the really important things in life. Last, I thank God, the first and last ultimate determinant, for providing me wonderful puzzles.

2024, Studies on Neotropical Fauna and Environment

The Richardiidae are acalyptrate dipterans about which very little is known. Here we describe male-male agonistic interactions and test a hypothesis of ant-mimicry in a new richardiid species in the genus Sepsisoma. Males of Sepsisoma sp. show several ritualized agonistic behaviors, with a clear escalation from simpler to more elaborate displays, which are described here in detail. We could distinguish four (not clearly discrete) behavioral stages during the escalation: Chase, Orientation, Leg display and Body raising. As the displays shifted from simpler to more elaborate, there was also a decrease in their relative frequency. Curiously, small males were by far the most aggressive, and most of their agonisms were directed to large males. The Sepsisoma flies in this study show a clear ant-like appearance, particularly resembling the formicine ant Camponotus crassus. We conducted laboratory experiments which support this hypothesis, providing the first experimental evidence that ant-like dipterans may deceive a potential predator.

2024, Environmental Management

Humans can dive with critically endangered grey nurse sharks (Carcharias taurus) along the east coast of Australia. This study investigated both compliance of tourist divers to a code of conduct and legislation and the behaviour of grey nurse sharks in the presence of divers. A total of 25 data collection dives were conducted from December 2008 to January 2009. Grey nurse shark and diver behaviour were documented using 2-min scan samples and continuous observation. The proportion of time spent observing human-shark interactions was 9.4% of total field time and mean human-shark interaction time was 15.0 min. Results were used to gauge the effectiveness of current management practices for the grey nurse shark dive industry at Fish Rock in New South Wales, Australia. Grey nurse shark dive tourists were compliant to stipulations in the code of conduct and legislation (compliance ranged from 88 to 100%). The research detailed factors that may promote compliance in wildlife tourism operations such as the clarity of the stipulations, locality of the target species and diver perceptions of sharks. Results indicated that grey nurse sharks spent the majority of their time milling (85%) followed by active swimming (15%). Milling behaviour significantly decreased in the presence of more than six divers. Distance between sharks and divers, interaction time and number of sharks were not significantly correlated with grey nurse shark school behaviour. Jaw gaping, rapid withdrawal and stiff or jerky movement were the specific behaviours of grey nurse sharks that occurred most frequently and were associated with distance between divers and sharks and the presence of six or more divers. Revision of the number of divers allowed per interaction with a school of grey nurse sharks and further research on the potential impacts that shark-diving tourism may pose to grey nurse sharks is recommended.

2024, Journal of Comparative Psychology

Real-life situations provide rich sets of cues that viewers evaluate in terms of their emotional significance. In this study, chimpanzees (Pan troglodytes) viewed a movie depicting naturalistic scenes involving the whole-body expressions of conspecifics to examine how nonhuman primates perceived the combination of these cues and how each cue contributed to the overall perception. Viewing time was measured while the chimpanzees watched movie clips without sound. Among scenes depicting neutrality, general excitement, agonism, and playfulness, chimpanzees looked longest at those depicting agonism. This bias toward agonistic scenes may indicate an attentional sensitivity toward threat/fear-related negative situations among chimpanzees. The effect disappeared when the images were scrambled, ruling out the possible effect of pixel-level properties on the results. In addition, the follow-up analyses revealed that the effect was independent of the presentation order and of the number of individuals in each clip. The manipulation of playback speeds had little effect on the looking times. The elimination of facial cues slightly influenced the looking times but did not change the strong bias toward agonistic scenes. This robustness of the main effect against image manipulations may indicate that the chimpanzees attended directly to the contextual information implied by the cues rather than to the cues per se (e.g., facial expressions, speed of movements).

2024, Journal of Abnormal Child Psychology

The current study examined whether proactive and reactive aggression were associated with the risk for initiation of substance use from fourth to ninth grade in a sample of 126 aggressive children (66% male). In addition, the study examined whether these functions of aggression increased risk for initiation via peer delinquency and peer rejection. Proactive aggression was marginally significantly directly associated with risk for initiation of alcohol use and indirectly associated with risk for initiation of marijuana and tobacco use through peer delinquency. Reactive aggression was associated with increased risk for initiation of tobacco and marijuana use through a complex chain that included both peer rejection and peer delinquency. However, high levels of reactive aggression that did not lead to peer rejection were negatively associated with risk for initiation of tobacco and marijuana use. Implications for intervention are discussed.

2024, Zoological Science

Fighting behavior in male crickets is already well described, and some of the mechanisms underlying aggression and aggressive motivation have already been revealed. Much less is known about female/female interactions. Here, we report that adult female crickets that had been isolated for several days readily entered into agonistic interactions with conspecific individuals. Characteristic dyadic encounters between isolated females escalated in a stepwise manner and were concluded with the establishment of a dominant/subordinate relationship. For 15 to 30 minutes following an initial fight, former subordinate females showed a dramatic change in agonistic behavior. If they were paired with the former dominant opponent during this interval, a significant majority did not enter into any aggressive interaction but instead actively avoided the opponent. A similar experience-based and time-dependent increase in avoidance was observed when former subordinate females were paired with unfamiliar naïve opponents. However, when faced with an unfamiliar subordinate individual in the second encounter, no such increase in avoidance behavior was observed. We propose that the observed changes in the behavior of former subordinate females are the consequence of a change in the general state of arousal and of the recognition of dominance status, but not of individual recognition. The fact that former dominant individuals did not show similar experience-based changes in agonistic behavior suggests that dominant/subordinate relationships between pairs of female crickets are maintained mainly by the behavior of subordinate individuals.

2024, Zoological Science

After a loss against an opponent, the aggressiveness of a male cricket is significantly reduced for up to 30 minutes. This depression of aggressiveness is an important factor in the establishment and maintenance of dominance between individuals. In the present study, we investigated the functional roles of nitric oxide (NO) signaling in the depression of aggressiveness in subordinate male crickets. Pairs of male crickets, pre-injected with various NO-related reagents, were allowed to establish dominant/subordinate relationships in dyadic encounters. Opponents were separated for 15 minutes and then paired again. In second encounters, subordinate crickets pre-injected with PTIO (NO scavenger) showed agonistic behavior towards former dominant opponents. A similar effect was observed in crickets pre-injected with L-NAME (NO synthase inhibitor) or ODQ (soluble guanylate cyclase inhibitor). The effects of the latter two drugs were canceled by co-injection of NOR3 (NO donor) with L-NAME or by co-injection of 8-Br-cGMP (cGMP-analog) with ODQ. Injection of NOR3 alone prolonged the inhibition of agonistic behavior in subordinate crickets from 30 minutes to 3 hours. Our results suggest that the change in agonistic behavior observed in subordinate male crickets is closely linked to NO-mediated cGMP signaling.

2024, Journal of Mammalogy

2024, Physiology & Behavior

This study assessed the reinforcing properties of successful intermale agonistic encounters between OFI male mice using the conditioned place preference paradigm. A three compartment apparatus was used and the procedure consisted of three phases: preconditioning (3 days), conditioning (8 days) and postconditioning (3 tests). Individually housed male mice were allocated to two groups. The aggression group confronted docile opponents in the preconditioning "less-preferred" compartment and were left alone in the "preferred" one. The control group was left alone in both compartments. Whereas no significant differences were found between both groups in the time spent in the less-preferred compartment, a separate analysis of animals in function of the color of the less-preferred compartment revealed a clear-cut difference. Mice developed a conditioned place preference for the aggression-paired compartment only if that experience took place in the black one. These findings suggest that the process of establishing a conditioned place preference with successful intermale aggression as reinforcer is extremely fragile and can be easily disrupted by changing the environmental cues involved.

2024, Journal of Neurophysiology

1. The release of ink from the ink gland of Aplysia californica in response to noxious stimuli is mediated by three electrically coupled motor neurons, L14A, L14B, L14C, whose cell bodies are located in the abdominal ganglion. The initial synaptic input to the ink motor neurons is relatively ineffective in firing the cells. As a result, a pause of 1--3 s often occurs before the cells attain their maximum firing frequency and cause the release of ink. Using current and voltage-clamp techniques we have analyzed the mechanisms underlying the firing pattern of these cells. 2. The presence of a fast transient K+ current appears to play an important role in mediating the firing pattern of the ink motor neurons. Their high resting potential (-75 mV) ensures that the steady-state level of inactivation of the conductance channels for the fast K+ current will normally be low. Thus a train of EPSPs or a depolarizing current pulse can activate this current maximally, thereby reducing the initia...

2024, Neuroscience & Biobehavioral Reviews

Individual differences in behaviour are a phenomenon that is more and more attracting the attention of scientists. Among the other reasons, behavioural individuality occurs because selection favours the adoption of different tactics by individuals. It is now widely recognized that within many vertebrate species, individuals vary along an axis the extremes of which are represented by individuals 'bold' and 'shy', sometimes called 'proactive' and 'reactive'. Here we present the case of feral domestic cats (Felis catus L.) living in group in the urban environment where showing bold attitudes is linked to the benefit of a high annual reproductive success but, on the other hand, to a high probability to be infected by the Feline Immunoficiency Virus (FIV), a lethal disease caused by a retrovirus. In this species, natural selection has probably favoured proactive temperament in spite of the cost represented by getting the disease. In fact, proactive individuals, even if FIV positive, reproduce more than reactive individuals before the last stage of FIV-infection (AIDS) characterized by a loss of immunological defences and subsequent opportunistic infections. Evolutionary implications are discussed.

2024, Science Advances

Fresh analysis of primate calls shows that speech dawned in monkeys some 100 times earlier than the appearance of modern humans.

2024, Brazilian Journal of Medical and Biological Research

Dominance status among female marmosets is reflected in agonistic behavior and ovarian function. Socially dominant females receive submissive behavior from subordinates, while exhibiting normal ovulatory function. Subordinate females, however, receive agonistic behavior from dominants, while exhibiting reduced or absent ovulatory function. Such disparity in female fertility is not absolute, and groups with two breeding females have been described. The data reported here were obtained from 8 female-female pairs of captive female marmosets, each housed with a single unrelated male. Pairs were classified into two groups: "uncontested" dominance (UD) and "contested" dominance (CD), with 4 pairs each. Dominant females in UD pairs showed significantly higher frequencies (4.1) of agonism (piloerection, attack and chasing) than their subordinates (0.36), and agonistic behaviors were overall more frequently displayed by CD than by UD pairs. Subordinates in CD pairs exhibited more agonistic behavior (2.9) than subordinates in UD pairs (0.36), which displayed significantly more submissive (6.97) behaviors than their dominants (0.35). The data suggest that there is more than one kind of dominance relationship between female common marmosets. Assessment of progesterone levels showed that while subordinates in UD pairs appeared to be anovulatory, the degree of ovulatory disruption in subordinates of CD pairs was more varied and less complete. We suggest that such variation in female-female social dominance relationships and the associated variation in the degree and reliability of fertility suppression may explain variations of the reproductive condition of free-living groups of common marmosets.

2024, Journal of Medicinal Chemistry

The incorporation of chemical modifications into the structure of bioactive compounds is often difficult because the biological properties of the new molecules must be retained with respect to the native ligand. Ergopeptides, with their high affinities at D 1 and D 2 dopamine receptors, are particularly complex examples. Here, we report the systematic derivatization of two ergopeptides with different peptidebased spacers and their evaluation by radioligand binding assays. Selected spacer-containing ergopeptides with minimal biological alteration and a proper anchoring point were further derivatized with a biotin reporter. Detailed characterization studies identified 13 as a biotin ergopeptide maintaining high affinity and agonist behavior at dopamine receptors, being a useful tool for the study of heteromers involving

2024, Behaviour

Although the individual elements of stickleback behaviour are well known, to date a robust investigation of the temporal cycling of aggressive, courtship and parental behaviour during the breeding cycle has been undertaken in only one species, the threespine stickleback, Gasterosteus aculeatus. In order to understand the evolution of behaviour in this fascinating group of fishes, comparative studies conducted upon other members of the Gasterosteidae are necessary. We thus documented the cyclic changes and structure of sixteen agonistic, parental and courtship displays across the breeding cycle for a population of brook sticklebacks, Culaea inconstans, from Nebraska and compared it to the temporal cycling of reproductive behaviour in the threespine. Our results indicate that in the brook stickleback: (1) aggressive behaviour varies temporally in response to a male, but not a female, intruder. (2) During those phases wherein the young are nest bound, aggressive and parental elements are negatively correlated. (3) The location of the focal fish within the tank during the trial is an accurate indicator of his primary motivation and (4), a sex specific differential response to intruding fish is apparent only during the courtship interval. The temporal structure of reproductive behaviour in the brook stickleback mirrors that of the threespine stickleback in three respects: (1) aggressive motivation across the breeding cycle exhibits a U-shaped distribution, with peak levels of aggression occurring in the nest-building stage and final days of parental care. (2) During the courtship phase sexual motivation supercedes aggression in response to the presence of a nuptially coloured female and (3), the pattern of parental fanning shows an inverted U-shaped distribution with peak frequencies coinciding with the hatching of the eggs.