The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Gregory F Ball - One of the best experts on this subject based on the ideXlab platform.
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social suppression of song is associated with a reduction in volume of a song control nucleus in european starlings Sturnus vulgaris
Behavioral Neuroscience, 2005Co-Authors: Jennifer J Sartor, Gregory F BallAbstract:: In seasonally breeding songbirds, variations in testosterone and song correlate with volume changes in brain nuclei associated with song, including the HVC. The authors tested whether singing can lead to activity-dependent increases in HVC volume by examining song output in starlings (Sturnus vulgaris). The authors manipulated males' environments so that only some were dominant with nestboxes, whereas others were not. Some of these males thus sang at higher rates and had larger HVC volume than others. The study was conducted over 2 years. In 1 year, males selectively occupied nestboxes but did not sing. HVC volume did not differ in these starlings, indicating that nestbox possession alone cannot increase HVC. The findings suggest that changes in song nuclei volume can be driven by changes in singing.
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evidence for opioid involvement in the regulation of song production in male european starlings Sturnus vulgaris
Behavioral Neuroscience, 2005Co-Authors: Lauren V Riters, Marcel Eens, Rianne Pinxten, Molly B Schroeder, Catherine J Auger, Gregory F BallAbstract:: Many social animals vocalize at high rates, suggesting that vocal communication is highly motivated and rewarding. In songbirds, much is known about the neural control of vocal behavior; however, little is known about neurobiological mechanisms regulating the motivation to communicate. This study examined a possible role for opioid neuropeptides in motivation and reward associated with song production in male European starlings (Sturnus vulgaris). Peripheral opioid blockade facilitated male song production. Furthermore, methionine-enkephalin immunolabeled fiber densities within brain regions in which opioids are known to regulate motivation and reward (i.e., the medial preoptic nucleus and ventral tegmental area) related positively to male song production. These data suggest that song production might be regulated by opioid activity within motivation and reward neural systems.
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song predicts immunocompetence in male european starlings Sturnus vulgaris
Proceedings of The Royal Society B: Biological Sciences, 2002Co-Authors: Deborah L Duffy, Gregory F BallAbstract:According to the immunocompetence handicap hypothesis, sexually selected characteristics predict immune function and this relationship is mediated by testosterone. In the present study, we investigated whether bird song could predict immunity in European starlings (Sturnus vulgaris). We recorded the singing and reproductive behaviours of 16 adult male starlings in an outdoor aviary and then assessed their cell-mediated and humoral immunity in vivo. The males were observed in groups of four for 2 h each day over a 4-day period. For each male, the number of songs produced was recorded and the average song-bout length was computed. Next, cell-mediated and humoral immunity were assessed via cutaneous swelling responses to the T-cell mitogen phytohaemagglutinin and antibody responses to a novel antigen, keyhole limpet haemocyanin. Song rate and song-bout length were positively correlated with cell-mediated and humoral immunity, respectively. Additionally, a negative relationship between plasma testosterone concentration and antibody response was observed. These data demonstrate that male starling song can be used as a predictor of immunocompetence, with more robust singers exhibiting enhanced immunity. Whether this relationship is mediated directly by testosterone requires further investigation.
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photoperiod induced testicular apoptosis in european starlings Sturnus vulgaris
Biology of Reproduction, 2001Co-Authors: Kelly A Young, Gregory F Ball, Randy J NelsonAbstract:To determine the extent to which testicular regression involves apoptotic cell death, photosensitive adult starlings were photostimulated for up to 9 wk by exposure to long-day (18 h of light) photoperiods. Apoptotic activity in recrudescing and regressing testes was assessed by in situ TUNEL labeling. Absolute testis mass in male starlings increased after 2 wk of photostimulation and subsequently decreased with continued longday exposure. Seminiferous tubule diameter also increased after 1‐3 wk of photostimulation, then decreased as photorefractoriness developed. Testosterone concentrations increased significantly by Week 2 of photostimulation and declined with further light exposure. TUNEL labeling was significantly elevated in germ cells with 4 wk of photostimulation. An approximate 7fold increase in the degree of apoptotic cell death was observed over the course of gonadal regression. Incidences of TUNEL labeling in somatic Sertoli cells also increased. Light and electron microscopy examination confirmed that these somatic cells displayed morphological characteristics of apoptotic death. In rodents, Sertoli cells have not been previously reported to die during gonadal regression. These results suggest that seasonal testicular regression in European starlings is mediated by apoptosis. apoptosis, seasonal reproduction, Sertoli cells, steroid hormones, testis
Alfonso Marzal - One of the best experts on this subject based on the ideXlab platform.
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molecular characterization of avian malaria in the spotless starling Sturnus unicolor
Parasitology Research, 2018Co-Authors: Jaime Muriel, Jeff A. Graves, Sergio Magallanes, Concepcion Salaberria, Miriam Casallopez, Alfonso MarzalAbstract:We studied the prevalence and genetic diversity of malaria parasites in the poorly investigated spotless starling (Sturnus unicolor) breeding in central Spain, aiming to describe the phylogenetic relationships among them and with other haemosporidians infecting the genus Sturnus. A total of 180 nestlings and 180 adult individuals from four different breeding seasons were screened for haemosporidian parasites using a nested PCR approach for the genera Plasmodium and Haemoproteus. Although the malaria prevalence ranged between years, the overall prevalence was 6.94%. Adults had a higher prevalence than chicks: 12.77 vs. 1.11%, respectively. We molecularly characterized avian malaria isolated in peripheral blood samples taken from malaria-infected individuals. Sequence analyses revealed four unique Plasmodium lineages of avian malaria (STURUNI01, STURUNI02, SYAT05, SGS1) in our spotless starling population. The phylogenetic analysis showed a well-supported clade comprised by STURUNI01, STURUNI02, and SYAT05. The most common lineage (SYAT05) has been previously found in 26 other avian host species, including populations of spotless starling in Portugal. Because this sedentary species is widely distributed throughout the Iberian Peninsula, we suggest that the local transmission of these lineages might place migratory birds at infection risk.
Katherine L Buchanan - One of the best experts on this subject based on the ideXlab platform.
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pollutants affect development in nestling starlings Sturnus vulgaris
Journal of Applied Ecology, 2011Co-Authors: Shai Markman, Alistair Dawson, Carsten Theodor Muller, David Pascoe, Katherine L BuchananAbstract:1. Pollutants as endocrine disrupting chemicals (EDCs) are of worldwide concern, due to their detrimental effects on the physiology and behaviour of wildlife. One major source of EDCs is sewage treatment works which serve as foraging grounds for many bird species. However, the risks of consuming EDCs to wild birds at these sites have been largely overlooked. 2. We have previously quantified contamination levels of invertebrates fromwithin filter beds of sewage treatment works and the intake rates of these invertebrates by wild European starlings feeding at these sites. Our work to date has shown that environmentally-relevant EDC exposure results in reduced immunocompetence, increased song behaviour and neural development in adult starlings. 3. In the present study, we hypothesized that nestling starlings exposed to similar EDC levels from contaminated prey, from parental feeding at sewage treatment works, would show altered growth and physiology. 4. Our findings show that EDC exposure results in reduced growth and immunocompetence in nestling birds. However, there was no effect on corticosterone or haematocrit levels. As growth rates and immunocompetence are likely to be related to survival rates, we suggest that these exposure levels are likely to adversely affect recruitment into the adult population. 5. Synthesis and applications. These results highlight the potential transfer of EDCs between semiaquatic or aquatic organisms and terrestrial organisms up the food chain at sites of sewage treatment works, broadening the scope of potential routes of exposure. Our findings suggest that birds foraging in these sites are at risk of physiological manipulation from EDCs and reduced body condition as a result. We advocate further work to evaluate the potential for EDCs from sewage treatment works to bioaccumulate and modulate the condition of wild organisms feeding on contaminated prey. Our results suggest that changes in management practices of sewage treatment works are required. We support measures to reduce EDC levels in sewage treatment works and that these sites should be designed to exclude or deter wildlife from foraging on contaminated prey. The management implications of such policy – oriented steps will ensure the health of wildlife foraging at sewage treatment works.
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developmental stress social rank and song complexity in the european starling Sturnus vulgaris
Proceedings of The Royal Society B: Biological Sciences, 2004Co-Authors: Karen A Spencer, Katherine L Buchanan, A R Goldsmith, Clive K CatchpoleAbstract:Bird song is a sexually selected trait and females have been shown to prefer males that sing more complex songs. However, for repertoire size to be an honest signal of male quality it must be associated with some form of cost. This experiment investigates the effects of food restriction and social status during development on song complexity in the European starling (Sturnus vulgaris). Birds that experienced an unpredictable food supply early in life produced a significantly smaller repertoire of song phrases than those with a constant food supply. Social status during development was also significantly correlated with repertoire size, with dominant birds producing more phrase types. This study therefore provides novel evidence that social as well as nutritional history may be important in shaping the song signal in this species.
Jeff A. Graves - One of the best experts on this subject based on the ideXlab platform.
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molecular characterization of avian malaria in the spotless starling Sturnus unicolor
Parasitology Research, 2018Co-Authors: Jaime Muriel, Jeff A. Graves, Sergio Magallanes, Concepcion Salaberria, Miriam Casallopez, Alfonso MarzalAbstract:We studied the prevalence and genetic diversity of malaria parasites in the poorly investigated spotless starling (Sturnus unicolor) breeding in central Spain, aiming to describe the phylogenetic relationships among them and with other haemosporidians infecting the genus Sturnus. A total of 180 nestlings and 180 adult individuals from four different breeding seasons were screened for haemosporidian parasites using a nested PCR approach for the genera Plasmodium and Haemoproteus. Although the malaria prevalence ranged between years, the overall prevalence was 6.94%. Adults had a higher prevalence than chicks: 12.77 vs. 1.11%, respectively. We molecularly characterized avian malaria isolated in peripheral blood samples taken from malaria-infected individuals. Sequence analyses revealed four unique Plasmodium lineages of avian malaria (STURUNI01, STURUNI02, SYAT05, SGS1) in our spotless starling population. The phylogenetic analysis showed a well-supported clade comprised by STURUNI01, STURUNI02, and SYAT05. The most common lineage (SYAT05) has been previously found in 26 other avian host species, including populations of spotless starling in Portugal. Because this sedentary species is widely distributed throughout the Iberian Peninsula, we suggest that the local transmission of these lineages might place migratory birds at infection risk.
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Isolation and characterization of polymorphic microsatellites isolated from the spotless starling (Sturnus unicolor) and cross‐species amplification in the European starling (Sturnus vulgaris)
Molecular Ecology Notes, 2006Co-Authors: P. Celis, Jeff A. GravesAbstract:Spotless and European starlings (Sturnus unicolor and Sturnus vulgaris) have attracted attention from researchers interested in sexual selection, evolution of parental care and reproductive strategies. Both species show high levels of intraspecific nest parasitism and extra-pair paternity, but research in this area is hampered by a lack of molecular markers specific for these species. Here, we describe a set of primers for nine microsatellite loci in spotless starlings, eight of which are highly polymorphic (7.37 alleles in average). These microsatellites are also polymorphic in European starlings (6.75 alleles in average).
Clive K Catchpole - One of the best experts on this subject based on the ideXlab platform.
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developmental stress social rank and song complexity in the european starling Sturnus vulgaris
Proceedings of The Royal Society B: Biological Sciences, 2004Co-Authors: Karen A Spencer, Katherine L Buchanan, A R Goldsmith, Clive K CatchpoleAbstract:Bird song is a sexually selected trait and females have been shown to prefer males that sing more complex songs. However, for repertoire size to be an honest signal of male quality it must be associated with some form of cost. This experiment investigates the effects of food restriction and social status during development on song complexity in the European starling (Sturnus vulgaris). Birds that experienced an unpredictable food supply early in life produced a significantly smaller repertoire of song phrases than those with a constant food supply. Social status during development was also significantly correlated with repertoire size, with dominant birds producing more phrase types. This study therefore provides novel evidence that social as well as nutritional history may be important in shaping the song signal in this species.
