61 resultados para Peixe-zebra


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Fipronil, a phenyl pyrazole pesticide, is aerially applied in eastern Australia to control locust outbreaks, usually as “Adonis 3UL Insecticide®” (BASF), an ultra low (UL) volume formulation containing 0.3% active pesticide. We tested the toxicities of technical-grade fipronil, the Adonis 3UL formulation and its components in zebra finch, a native bird at risk of exposure in locust control regions. We estimated oral-dose LD50 by the Up-and-Down method. Under laboratory conditions, we identified unexpectedly high toxicities due exclusively to diacetone alcohol (DAA), a solvent making up 12.5% of the Adonis 3UL formulation. In contrast, finches were asymptomatic when exposed to 0.3% technical grade fipronil dissolved in a minimum amount of acetone. Depending upon the behaviour and persistence of DAA under field conditions, this formulation of Adonis 3UL may pose a far greater threat to the health of small birds and possibly other vertebrates than expected for fipronil alone.

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There is growing evidence that ultraviolet (UV) wavelengths play an important role in avian mate choice. One of the first experiments to support this idea showed that female zebra finches (Taeniopygia guttata) prefer UV-reflecting males to males whose ultraviolet reflection has been removed. The effect was very strong despite little or no UV reflection from several plumage areas. However, it is not clear how the importance of the UV waveband compares to other regions of the bird-visible spectrum. We tested whether the response of female zebra finches to the removal of male UV reflection is greater than to the removal of other wavebands. We presented females with a choice of males whose appearance was manipulated using coloured filters. The filters removed single blocks of the avian visible spectrum corresponding closely to the spectral sensitivities of each of the zebra finch's single cone classes. This resulted in males that effectively had no UV (UV-), no short-wave (SW-), no medium-wave (MW-) or no long-wave (LW-) plumage reflection. Females preferred UV- and SW- males. LW- and MW- males were least preferred, suggesting that female zebra finches show the greatest response to the removal of longer wavelengths. Quantal catches of the single cone types viewing body areas of the male zebra finch are presented for each treatment. Our study suggests it is important to consider the role of the UV waveband in avian mate choice in conjunction with the rest of the avian visible spectrum.

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There is considerable interest in the role that ultraviolet (UV) cues play in the foraging and mate choice decisions of birds. However, with the exception of the zebra finch, Taeniopygia guttata, it is not yet clear whether ultraviolet preferences are context specific, or whether birds show a general preference for full-avian-spectrum environments 320-700 nm) irrespective of the activity in which they are engaged. We investigated whether European starlings, Sturnus vulgaris, and blue tits, Parus caeruleus, show general (nonresource based) or context-specific preferences for full-spectrum environments. We found that neither species showed a general preference for UV-present (UV+) over UV-deficient (UV-) environments, when those environments contained no resources (experiment 1). Furthermore, neither species showed a UV+ preference when cages contained food, water and perches (starlings; experiment 2) or food, perches and heterospecifics (blue tits; Hunt et al. 1999. Animal Behaviour, 58, 809-815). However, both species did show highly significant preferences for UV+ conditions when viewing potential mates. Such experiments are necessary before one can conclude that particular wavebands have specific relevance to mate choice. In fact, our results suggest that the importance of particular wavelength compositions do indeed vary with behavioural context. (C) 2002 The Association for the Study of Animal Behaviour.

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In this study zebrafish were used to identify, characterize and study leukemic "cancer"-genes as well as to investigate their role in normal development, particularly blood cell development. The experiments demonstrated that zebrafish represent an excellent tool for studying leukemogenesis, the genes involved in this process and for testing anti-cancer therapeutics.

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Suppressors of cytokine signalling (SOCS) proteins are negative regulators of the JAK-STAT pathway which is perturbed in certain disease states including cancers and inflammatory diseases. This thesis ascertained the suitability of zebrafish as an alternative animal model to study the SOCS proteins which established new and additional roles during development.

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This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis · Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross-tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.

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Distributional and habitat information on eight introduced bird species in north Sulawesi, Indonesia, is presented. The accounts are based on our observations as well as being gathered from published sources and unpublished trip reports. Three species (Sulphur-crested Cockatoo Cacatua galerita, Sooty-headed Bulbul Pycnonotus aurigaster and Red-collared Dove Steptopelia tranquebarica) have not previously been reported in north Sulawesi in the published literature, while the continued presence and status of Java Sparrow Padda oryzivora, Zebra Dove Geopelia striata and Rock Dove Columba livia was considered uncertain in the published literature. Further work is required systematically to document the distribution, status and spread of introduced species in the north and other parts of Sulawesi—an imperative from both an economic and conservation perspective.

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Although the costs of parental care are at the foundations of optimal-parental-investment theory, our understanding of the nature of the underlying costs is limited by the difficulty of measuring variation in foraging effort. We simultaneously measured parental provisioning and foraging behavior in a free-living population of Zebra Finches (Taeniopygia guttata) using an electronic monitoring system. We fitted 145 adults with a passive transponder tag and remotely recorded their visits to nest boxes and feeders continuously over a 2-month period. After validating the accuracy of this monitoring system, we studied how provisioning and foraging activities varied through time (day and breeding cycle) and influenced the benefits (food received by the offspring) and costs (interclutch interval) of parental care. The provisioning rates of wild Zebra Finches were surprisingly low, with an average of only one visit per hour throughout the day. This was significantly lower than those reported for this model species in captivity and for most other passerines in the wild. Nest visitation rate only partially explained the amount of food received by the young, with parental foraging activity, including the minimum distance covered on foraging trips, being better predictors. Parents that sustained higher foraging activity and covered more distance during the first breeding attempt took longer to renest. These results demonstrate that in some species matching foraging activity with offspring provisioning may provide a better estimate of the true investment that individuals commit to a reproductive attempt.

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Social interactions with adults are often critical for the development of mating behaviours. However, the potential role of other primary social partners such as juvenile counterparts is rarely considered. Most interestingly, it is not known whether interactions with juvenile females improve males’ courtship and whether, similar to the winner and loser effects in a fighting context—outcome of these interactions shapes males’ behaviour in future encounters. We investigated the combined effects of male quality and juvenile social experience on pairing success at adulthood in zebra finches (Taeniopygia guttata). We manipulated brood size to alter male quality and then placed males in either same- or mixed-sex juvenile dyads until adulthood. We found that males from reduced broods obtained more copulations and males from mixed-sex dyads had more complete courtships. Furthermore, independent of their quality, males that failed to pair with juvenile females, but not juvenile males, had a lower pairing success at adulthood. Our study shows that negative social experience with peers during adolescence may be a potent determinant of pairing success that can override the effects of early environmental conditions on male attractiveness and thereby supports the occurrence of an analogous process to the loser effect in a mating context.

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Repeated interactions between individuals in socially living animals select for the evolution of signals that convey information identifying individuals or categories of individuals, which may enable the discrimination of familiar versus unfamiliar individuals. Such information may help animals maximize their inclusive fitness by adjusting their own behaviour, allowing them to avoid conflict, preferentially direct help and/or ignore unreliable individuals. Acoustic signals in birds provide the potential to encode individual-specific information. We examined the degree to which individual identity, sex, breeding status, group membership and genetic relatedness were related to variability in six different call types, which occurred across a variety of different behavioural contexts in the apostlebird, Struthidea cinerea, a socially living and cooperatively breeding Australian passerine. We demonstrated that not all calls reflected the same extent of information. Of the six call types, call variation was related to individual identity in three call types, breeding status in two call types and sex and group relatedness in one call type. Finally, variation in two call types was not related to any of the measured variables. Our results suggest that some, but not all, acoustic signals in apostlebirds may be selected for individual distinctiveness between individuals and categories of individuals (male versus female, breeder versus nonbreeder), and these signals may be important in determining levels of cooperation and interaction between individuals in this cooperatively breeding society. © 2014 The Association for the Study of Animal Behaviour.

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The existence of animal personality is well-established across a wide range of species, with the majority of evidence for this being obtained from individuals held in captivity. However, there has been little work assessing the influence of commonly-measured personality traits on fitness, which is pertinent when the genetic basis of personality is considered. We measured whether the reproductive behaviour and success of zebra finches in a captive mixed-sex aviary environment was influenced by an aspect of their personality, their exploratory behaviour in a single-sex social aviary. We found that more exploratory males made a greater number of breeding attempts and raised more nestlings than less exploratory males. These results were not confounded by extra-pair paternity, which was not related to personality, or by the individuals that did not initiate any reproductive attempts at all. Our work provides evidence that attributes of personality may influence the degree to which individuals cope with, and thrive in a captive environment and this should be accounted for in both experimental design and the interpretation of results. Furthermore, this suggests that there may be selection on these traits as part of the domestication process.

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Phenotypic correlations (rP) have frequently been observed between physiological and behavioural traits, and the nature of these associations has been shown to be modulated by a range of environmental stressors. Studies to date have examined the effects of acute stressors on physiology-behaviour interrelations, but the potential for permanent changes induced by exposure to stress during development remains unexplored. We exposed female zebra finches to dietary restriction during the nestling stage and tested how this affected rP among a variety of physiological traits (haematocrit, stress-induced corticosterone level and basal metabolic rate (BMR)) and behavioural traits (activity and feeding rates in novel and familiar environments). Developmental stress completely uncoupled the relationship between activity in a novel environment and two physiological traits: haematocrit and BMR. This suggests that nutritionally based developmental stress has provoked changes in the energy budget that alleviate the trade-off between maintenance (BMR) and locomotor activities.

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Olfaction is an ancient sensory capability, and yet while it is now widely recognized that birds have olfactory mechanisms, use of the sense within a social context has been largely overlooked. In our study, we aimed to determine, for the first time, whether plumage odour may contribute to avian subspecies discrimination. We used a species complex, the crimson rosella, Platycercus elegans, which exhibits large geographical and phenotypic differences. Across 2 years in a wild population of P.elegans elegans we tested whether females at the nest could: (1) discriminate odours of conspecifics; (2) discriminate odours of subspecies; (3) discriminate odours of sexes of conspecifics; and (4) habituate at different rates to odour treatments. We found that female response differed between odours of feathers of consubspecifics, heterosubspecifics, heterospecific controls and sham controls and between odours of sexes of conspecifics. Across all odour treatments, we found habituation to the odour and the rate of habituation differed between odour treatments. Our results indicate that P.e. elegans females are able to discriminate conspecifics, consubspecifics and sexes based on plumage odour. To our knowledge, this is the first work to show that birds of a certain subspecies can discriminate the odour of its own subspecies from that of other subspecies. Our findings suggest that olfaction in birds may play a larger role than hitherto considered, and may even act as a signal to maintain or promote population divergence. © 2014 The Association for the Study of Animal Behaviour.

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The challenges of maintaining cohesion while making collective decisions in social or aggregating insects can result in the emergence of a leader or leaders. Larval aggregations of the steel-blue sawfly Perga affinis forage nocturnally, and some larvae lead the aggregation on foraging trips more often than expected by chance. We investigated the relationship between these leader and follower roles by comparing the weight and growth of individual larvae with different roles. Our observations reveal no significant difference between the growth of leaders and followers, suggesting that the role of leadership may not provide direct foraging benefits. However, by experimentally manipulating the social structure of larval aggregations, we found that individuals within aggregations that comprise a mixture of leaders and followers enjoy higher growth rates than those in aggregations comprising a single behavioural type. These data demonstrate, for the first time, individual benefits to maintaining a balance of leader and follower roles within larval aggregations, and highlight the importance of considering the perspectives of both leaders and followers when investigating the evolutionary significance of this behavioural variation within animal groups.

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This article is part of a Special Issue SBN 2014. Photoperiod and the hormonal response it triggers are key determinants of reproductive timing in birds. However, other cues and physiological traits may permit flexibility in the timing of breeding and perhaps facilitate adaptation to global change. Opportunistic breeders are excellent models to study the adaptive significance of this flexibility, especially at the individual level. Here, we sought to quantify whether particular male physiological and behavioral traits were linked to reproductive timing and output in wild-derived zebra finches. We repeatedly assessed male stress-induced corticosterone levels (CORT), basal metabolic rate (BMR), and activity before releasing them into outdoor aviaries and quantifying each pair's breeding timing, investment, and output over a seven-month period. Despite unlimited access to food and water, the colony breeding activity occurred in waves, probably due to interpair social stimulations. Pairs adjusted their inter-clutch interval and clutch size to social and temperature cues, respectively, but only after successful breeding attempts, suggesting a facultative response to external cues. When these effects were controlled for statistically or experimentally, breeding intervals were repeatable within individuals across reproductive attempts. In addition, males' first laying date and total offspring production varied with complex interactions between pre-breeding CORT, BMR and activity levels. These results suggest that no one trait is under selection but that, instead, correlational selection acts on hormone levels, metabolism, and behavior. Together our results suggest that studying inter-individual variation in breeding strategy and their multiple physiological and behavioral underpinnings may greatly improve our understanding of the mechanisms underlying the evolution of breeding decisions.