Fighting fruit flies: a model system for the study of aggression.
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Despite the importance of aggression in the behavioral repertoire of most animals, relatively little is known of its proximate causation and control. To take advantage of modern methods of genetic analysis for studying this complex behavior, we have developed a quantitative framework for studying aggression in common laboratory strains of the fruit fly, Drosophila melanogaster. In the present study we analyze 73 experiments in which socially naive male fruit flies interacted in more than 2,000 individual agonistic interactions. This allows us to (i) generate an ethogram of the behaviors that occur during agonistic interactions; (ii) calculate descriptive statistics for these behaviors; and (iii) identify their temporal patterns by using sequence analysis. Thirty-minute paired trials between flies contained an average of 27 individual agonistic interactions, lasting a mean of 11 seconds and featuring a variety of intensity levels. Only few fights progressed to the highest intensity levels (boxing and tussling). A sequential analysis demonstrated the existence of recurrent patterns in behaviors with some similarity to those seen during courtship. Based on the patterns characterized in the present report, a detailed examination of aggressive behavior by using mutant strains and other techniques of genetic analysis becomes possible. (+info)
Regulation of reproduction in a queenless ant: aggression, pheromones and reduction in conflict.
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In the monogynous queenless ant Diacamma ceylonense, the future reproductive (future gamergate) is very aggressive towards infertile workers during the first days of her adult life. Overt aggression disappears at about three weeks, when the future gamergate begins to lay male-destined eggs and is ready to mate. Over the same period, her cuticular hydrocarbon profile alters, changing from a chemical signature similar to that of a sterile worker towards that of a gamergate. In nature, these behavioural and chemical changes will coincide with a reduction in conflict within the nest: faced with a virgin future gamergate, infertile workers have an interest in producing male-destined eggs; however, once the gamergate produces female eggs, they have an interest in rearing her offspring. This demonstration of a shift from physical inhibition to chemical signalling is interpreted in terms of sociogenetic theory, the role of cuticular hydrocarbons as an indicator of fertility in insects and the fact that the regulation of reproduction in Diacamma involves mechanisms redolent of both queenless and queenright ant species. (+info)
Standards in school toilets--a questionnaire survey.
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BACKGROUND: Children often say they have problems with their toilets in school. Educationalists and health workers need to be aware of potential difficulties, to try and improve these facilities for school children. The objective of this study was to assess the perception children have of the toilet facilities in their schools and whether or not this influences their use of them. METHODS: An interviewer-administered questionnaire was given to children attending community audiology clinics and their parents. RESULTS: Eighty-seven children from 65 schools were surveyed. Poorly maintained and unhygienic facilities were described to which access was restricted. A significant proportion of children were bullied or teased. Forty per cent would never open their bowels using the toilets in school. CONCLUSION: The same standards for toilet facilities in the workplace should apply to schools. Substandard facilities may contribute to the suppression of the 'call to stool', leading to chronic constipation. Infectious illnesses may be more easily spread. (+info)
Nursing workforce retention: challenging a bullying culture.
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Discussions surrounding nursing shortages typically focus on recruitment, but retention is also a problem. Emerging research suggests that intimidation in the nursing workforce is a problem that planners need to deal with as part of an overall strategy aimed at maintaining a balance between supply and demand. This paper explores issues surrounding intimidation in the nursing workforce and looks at how one major teaching hospital in Australia attempted to address the problem. (+info)
Bimodal signal requisite for agonistic behavior in a dart-poison frog, Epipedobates femoralis.
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Animal acoustic signals play seminal roles in mate attraction and regulation of male spacing, maintenance of pairbonds, localization of hosts by parasites, and feeding behavior. Among vertebrate signals, it is becoming clear that no single stereotyped signal feature reliably elicits species-specific behavior, but rather, that a suite of characters is involved. Within the largely nocturnal clade of anuran amphibians, the dart-poison frog, Epipedobates femoralis, is a diurnal species that physically and vigorously defends its calling territory against conspecific intruders. Here we report that physical attacks by a territorial male are provoked only in response to dynamic bimodal stimuli in which the acoustic playback of vocalizations is coupled with vocal sac pulsations, but not by either unimodal cues presented in isolation or static bimodal stimuli. These results suggest that integration of dynamic bimodal cues is necessary to elicit aggression in this species. (+info)
Reproductive behavior in the squid Sepioteuthis australis from South Australia: interactions on the spawning grounds.
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Squid behavior is synonymous with distinctive body patterns, postures, and movements that constitute a complex visual communication system. These communications are particularly obvious during reproduction. They are important for sexual selection and have been identified as a potential means of species differentiation. Here we present a detailed account of copulation, mating, and egg deposition behaviors from in situ observations of the squid Sepioteuthis australis from South Australia. We identified four mating types from 85 separate mating attempts: "Male-upturned mating" (64% of mating attempts); "Sneaker mating" (33%); "Male-parallel" (2%); and "Head-to-head" (1%). Intervals between successive egg deposition behaviors were clearly bimodal, with modes at 2.5 s and 70.0 s. Ninety-three percent of egg capsules contained 3 or 4 eggs (mean = 3.54), and each egg cluster contained between 218 and 1922 egg capsules (mean = 893.9). The reproductive behavior of S. australis from South Australia was different from that described for other cephalopod species. More importantly, comparison between these results and those for other populations of S. australis suggests that behavior may differ from one population to another. (+info)
Field observations of intraspecific agonistic behavior of two crayfish species, Orconectes rusticus and Orconectes virilis, in different habitats.
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Agonistic behavior is a fundamental aspect of ecological theories on resource acquisition and sexual selection. Crustaceans are exemplary models for agonistic behavior within the laboratory, but agonistic behavior in natural habitats is often neglected. Laboratory studies do not achieve the same ecological realism as field studies. In an attempt to connect laboratory results to field data and investigate how habitat structure affects agonistic interactions, the nocturnal behavior of two crayfish species was observed by scuba diving and snorkeling in two northern Michigan lakes. Intraspecific agonistic interactions were analyzed in three habitats: two food resources-macrophytes and detritus-and one sheltered habitat. The overall observations reinforce the concept that resources influence agonistic bouts. Fights in the presence of shelters were longer and more intense, suggesting that shelters have a higher perceived value than food resources. Fights in the presence of detritus patches had higher average intensities and ended with more tailflips away from an opponent, suggesting that detritus was a more valuable food resource than macrophytes. In addition, observations of aggressive behavior within a natural setting can add validity to laboratory studies. When fights in nature are compared with laboratory fights, those in nature are shorter, less intense, and less likely to end with a tailflip, but do show the fundamental fight dynamics associated with laboratory studies. Extrinsic and intrinsic factors affect intraspecific aggression in many ways, and both should always be recognized as having the potential to alter agonistic behavior. (+info)
Effect of the establishment of dominance relationships on cortisol and other metabolic parameters in Nile tilapia (Oreochromis niloticus).
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The objective of the present study was to investigate the influence of the establishment of dominance relationships and social stress on plasma cortisol and metabolite levels in Nile tilapia (Oreochromis niloticus). During the 30-day experiment, the fish weighing 236 29 g were kept in individual aquaria, except for two pairings lasting 6 h each. Blood samples were taken from the animals before and after pairing. Display, approach, attack, rebuff, chase flight, and coloration were carried out on days 16 and 30. Activities and behaviors characteristic of the establishment of dominance relationships were described. It was possible to classify all experimental fish (N = 30) as dominant or subordinate. No differences were detected between dominant (N = 15) and subordinate (N = 15) fish during isolation or after pairing in cortisol (isolated: 5.76 0.98 vs 5.42 0.63; paired: 10.94 1.62 vs 11.21 2.45 g/dl), glucose (isolated: 60.02 4.9 vs 67.85 16.16; paired: 110.44 15.72 vs 136.26 22.46 mg/dl), triglyceride (isolated: 167.87 5.06 vs 185.68 7.24; paired: 210.85 13.40 vs 221.82 12.70 mg/dl) or total protein levels (isolated: 7.01 0.42 vs 6.69 0.59; paired: 9.21 0.62 vs 9.51 0.66 g/dl). However, when isolated (N = 30) and paired (N = 30) tilapia were compared, there were significant differences in cortisol and metabolite levels. The similar response presented by dominant and subordinate tilapia indicates that establishment of dominance relationships was a stressor for both groups. (+info)