49 research outputs found

    Serial monogamy benefits both sexes in the biparental convict cichlid

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    Monogamy can be either long-term or serial, with new pairs formed with each breeding bout. Costs and benefits are associated with each strategy. Because biparental convict cichlids (Amatitlania nigrofasciata) typically switch mates, exhibiting serial monogamy, we tested for the costs associated with forcing individuals to remain with the same mate. Convict cichlids were observed over two successive breeding bouts, either with the same or a new, equally experienced, mate. Parental behavior did not differ between breeding bouts, nor did brood size. Surprisingly, fish that remained with their original partner for a second bout took significantly longer to produce a brood compared to fish that paired with new partners. New partners were also more likely to successfully produce a second brood than re-mated partners. This is in contrast to the majority of bird studies that show many benefits to staying with the same partner for multiple broods. In convict cichlids, there seems to be no benefit associated with remaining with the same partner and switching mates reduces duration between broods for both males and females, potentially increasing overall reproductive success

    Prey naiveté and risk-sensitive courtship

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    a b s t r a c t a r t i c l e i n f o The assimilation of behavioral and evolutionary processes into conservation management provides insights into how invasive predators affect native fauna. The Indo-Pacific lionfish (Pterois volitans) has caused extensive reduction in the abundance of small-bodied reef fish within their introduced range. One possible mechanism facilitating this high predation rate may be due to prey exhibiting evolutionary naiveté toward this invasive predator. Here, we tested for the potential role of prey naiveté by examining the behavioral response of a prey species, the beaugregory damselfish (Stegastes leucostictus), toward this invasive predator. Damselfish demonstrated invasive predator recognition and subsequent anti-predator behavior, which may attenuate the impact posed by this invasive predator. However, damselfish under predation threat failed to modulate courtship behavior in the presence of lionfish. Therefore, benefits derived from the ability to recognize and respond appropriately to lionfish may be of little consequence if damselfish are unable to curtail high-risk courtship behavior in their presence

    Phase III multicenter clinical trial of the sialyl-TN (STn)-keyhole limpet hemocyanin (KLH) vaccine for metastatic breast cancer

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    PURPOSE. This double-blind, randomized, phase III clinical trial evaluated time to progression (TTP) and overall survival in women with metastatic breast cancer (MBC) who received sialyl-TN (STn) keyhole limpet hemocyanin (KLH) vaccine. Secondary endpoints included vaccine safety and immune response. EXPERIMENTAL DESIGN. The study population consisted of 1,028 women with MBC across 126 centers who had previously received chemotherapy and had had either a complete or a partial response or no disease progression. All women received one-time i.v. cyclophosphamide (300 mg/m(2)) 3 days before s.c. injection of 100 μg STn-KLH plus adjuvant (treatment group) or 100 μg KLH plus adjuvant (control group) at weeks 0, 2, 5, and 9. Subsequently, STn-KLH without adjuvant or KLH without adjuvant was then administered monthly for 4 months, and then quarterly until disease progression, without cyclophosphamide. RESULTS. STn-KLH vaccine was well tolerated; patients had mild to moderate injection-site reactions and reversible flu-like symptoms. Week-12 antibody testing revealed high specific IgG titers and a high rate of IgM-to-IgG seroconversion; the median IgG titers in STn-KLH recipients were 320 (anti-ovine submaxillary mucin) and 20,480 (anti-STn), with no detectable antimucin antibodies in the control group. The TTP was 3.4 months in the treatment group and 3.0 months in the control group. The median survival times were 23.1 months and 22.3 months, respectively. CONCLUSIONS. Although STn-KLH was well tolerated in this largest to date metastatic breast cancer vaccine trial, no overall benefit in TTP or survival was observed. Lessons were learned for future vaccine study designs

    Playing with the Rules: Influences on the Development of Regulation in Sport

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    Sport today is a rule-governed practice: constitutive rules, both prescriptive and proscriptive, define required equipment and facilities as well as setting the formal rules of play; auxiliary rules specify and control eligibility: and regulatory rules place restraints on behaviour independent of the sport itself. This article offers a broad sweep examination of the historical process of rule development in sport including an assessment of the influence over time of gambling, fair play ideology, economic pressures, technological developments and legal intervention. En route a seven-stage scheme of constitutive rule development is postulated which it is hoped will set a research agenda for sports historians to test with case studies of particular sports

    Pair-bond Formation and Breeding-site Limitation in the Convict Cichlid, Archocentrus Nigrofasciatus

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    Convict cichlids (Archocentrus nigrofasciatus) form pair bonds, are serially monogamous, and give biparental care to their offspring. Males and females may individually establish a breeding site before courtship, or they may form a pair and then obtain a breeding site together. Such sites are important resources for convict cichlids, and their availability often limits reproduction. Here, we examined if variation in breeding-site availability affected pair bonding between males and females and aggressive behaviors between bonded pairs. Groups of three males and three females were placed in large aquaria and randomly assigned to the following treatments: (1) the fish were provided with two breeding sites; (2) the fish were provided with two breeding sites throughout the experiment, one of which was later removed; (3) the fish were provided with one breeding site initially, and a second was later added; (4) the fish were provided with no breeding sites throughout the experiment. We found that pair bonds rarely formed when no breeding sites were provided; however, pair-bond formation was not limited by breeding-site number when at least one breeding site was available. In addition, there were no differences in aggression by paired individuals after breeding site manipulation, perhaps indicating that changes in the subsequent availability of breeding sites after pair formation did not influence a pair’s aggression

    QUALITATIVE BEHAVIOR OF A PUPFISH (CYPRINODON ATRORUS) IN DIFFERING ENVIRONMENTS

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    Volume: 29Start Page: 169End Page: 18

    Conservation and conflict between endangered desert fishes

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    Conservation of naturally sympatric endangered species requires unique considerations. While impacts of invasive species garner much attention, interactions between endangered species must also be managed. The endangered Leon Springs pupfish, Cyprinodon bovinus, has suffered a population decline due to decreasing natural habitat. As breeding habitat is lost, C. bovinus is also adversely affected by the sympatric, endangered Pecos gambusia, Gambusia nobilis. Here, we document interactions between these species, finding significantly more G. nobilis accumulated at pupfish spawning events than randomly distributed on breeding grounds in the absence of spawning. As a known egg predator, our results suggest that G. nobilis presence at spawnings may further decrease pupfish numbers while also altering the evolutionary dynamics of C. bovinus breeding tactics. Habitat restoration may decrease Gambusia concentrations or influence C. bovinus breeding behaviour and increase the number of territorial males resulting in viable population sizes for both critically endangered fishes

    Assessment and decision-making in a Caribbean damselfish: nest-site quality influences prioritization of courtship and brood defence

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    In systems where territory quality varies, animals are expected to exhibit plasticity in behaviour in order to maximize fitness relative to their present territory quality. This requires assessment of territory quality followed by decision-making in relation to the priority of activities necessary for survival and reproduction. We examined how differences in territory quality of beaugregory damselfish (Stegastes leucostictus) influence the prioritization of courtship and egg defence by comparing behavioural responses of males defending artificial sites (high quality) with males defending natural sites (low quality) when presented with an egg predator, a conspecific female, and a simultaneous choice between both. A significant three-way interaction of territory quality, presentation type and stimulus was observed for time near stimuli. In paired presentations, males defending low-quality territories spent more time near a female and less near an egg predator; while males on high-quality territories spent more time near a predator than a female. Additionally, comparing single and paired presentations reveals that behaviours towards egg predators remain constant while behaviours towards females decrease with paired stimuli. These data suggest that territory quality and ecological context impact decision-making and the relative values of potential reproduction and/or past reproductive effort

    Male convict cichlid 11-ketotestosterone levels throughout the reproductive cycle: an exploratory profile study in laboratory and field populations

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    The convict cichlid (Amatitlania nigrofasciata) has been extensively examined in relation to many behavioral topics, such as courtship, pair-bonding, bi-parental care, and territoriality. Recently, this model species has been utilized in studies on genetics, endocrinology, and neuroanatomy, with an ultimate goal of connecting behavior with its underlying mechanisms. The goal of this study was two-fold: (1) profile the circulating levels of plasma 11KT in the male convict cichlid at multiple points during the reproductive cycle and (2) generally compare the hormonal profiles of the widely used laboratory populations and those of a free-living population in the streams of Costa Rica. The results of the field experiment showed that male convict cichlids had higher levels of circulating 11KT during courtship and lower during the parental care and non-breeding phases. The profile of the laboratory population was similar to the profile of the free-living individuals, with significantly higher levels of 11KT occurring during courtship than during parental care, though the level of 11KT during non-breeding phase was elevated in the laboratory. The high levels of 11KT during courtship and low levels of 11KT during parental care found in both the field and the laboratory is similar to what has been reported in other species of teleosts, and may suggest an important function of 11KT in the expression of courtship behavior and the subsequent onset of parental behaviors in this model species
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