The phenotypic traits of high prolificacy, low fat on the rib eye muscle and high tolerance to internal parasites make the Barbados Blackbelly （BBB） sheep a valuable economic resource for small subsistence farmers o...The phenotypic traits of high prolificacy, low fat on the rib eye muscle and high tolerance to internal parasites make the Barbados Blackbelly （BBB） sheep a valuable economic resource for small subsistence farmers on some Caribbean islands. However, the determination of what is a purebred BBB sheep has long been a contentious issue because of the subjectivity. It is therefore necessary to have a more reliable means of identifying what is a purebred BBB sheep for purposes of conservation and breed improvement. Three geographically isolated populations of BBB sheep were genetically analysed at 19 microsatellite loci. Eighteen of the microsatellites were found to be useful for genetic analysis of the BBB sheep, based on polymorphic information content （PIC） values （0.5 〈 PIC 〉 0.25）. One microsatellite was not useful for genetic analysis based on PIC （0.111）, however it is considered to be a locus of interest because it is fully inbred （f = 1） and homozygous in all of the populations analysed. The analysis also showed that the purebred population of BBB sheep can be distinguished from other populations by formation of distinct clusters when subjected to analysis of molecular variance （AMOVA） and the construction of a rooted consensus tree using the Neighbour-Joining method and pair-wise distances based on marker estimated kinships.展开更多
House geckos in the genus Hemidactylus are highly successful colonizers of regions beyond their native range,with colonization often resulting in displacement of native gecko species through competitive interactions f...House geckos in the genus Hemidactylus are highly successful colonizers of regions beyond their native range,with colonization often resulting in displacement of native gecko species through competitive interactions for daytime refuge(crevices)and prey resources.We report on data collected from nighttime surveys undertaken in April-May 2014 on Barbados,West Indies,that focused on the distribution and abundance of the endemic Barbados leaf-toed gecko(Phyllodactylus pulcher)and the introduced tropical house gecko(Hemidactylus mabouia)along unlit coastal walls and among boulders in the grounds of a hotel resort.In contrast to patterns of displacement of native species by H.mabouia seen elsewhere,P.pulcher was more abundant than H.mabouia on coastal walls,whereas the latter was found in greater numbers using boulders at this site.Walls and boulders differed with regard to availability of diurnal refugia suitable for geckos,with the walls having high frequency of small crevices with openings<20 mm,and boulders offering very little cover other than the underside of the boulder itself.To investigate whether this niche separation was a result of differences in diurnal refuge use between the species,we conducted experimental trials in which geckos were allowed to select between refugia with different characteristics.Both species selected for narrower and warmer refugia,and refugia that had been previously occupied by the other species.These shared preferences for refugia type suggest that other factors underlie the niche separation observed in the field.In supporting high densities of P.pulcher,coastal walls could offer important secondary habitat by augmenting the natural cliff side habitat of this endemic gecko,a finding that could be exploited for the conservation of this candidate species for Critically Endangered classification.展开更多
文摘The phenotypic traits of high prolificacy, low fat on the rib eye muscle and high tolerance to internal parasites make the Barbados Blackbelly （BBB） sheep a valuable economic resource for small subsistence farmers on some Caribbean islands. However, the determination of what is a purebred BBB sheep has long been a contentious issue because of the subjectivity. It is therefore necessary to have a more reliable means of identifying what is a purebred BBB sheep for purposes of conservation and breed improvement. Three geographically isolated populations of BBB sheep were genetically analysed at 19 microsatellite loci. Eighteen of the microsatellites were found to be useful for genetic analysis of the BBB sheep, based on polymorphic information content （PIC） values （0.5 〈 PIC 〉 0.25）. One microsatellite was not useful for genetic analysis based on PIC （0.111）, however it is considered to be a locus of interest because it is fully inbred （f = 1） and homozygous in all of the populations analysed. The analysis also showed that the purebred population of BBB sheep can be distinguished from other populations by formation of distinct clusters when subjected to analysis of molecular variance （AMOVA） and the construction of a rooted consensus tree using the Neighbour-Joining method and pair-wise distances based on marker estimated kinships.
文摘House geckos in the genus Hemidactylus are highly successful colonizers of regions beyond their native range,with colonization often resulting in displacement of native gecko species through competitive interactions for daytime refuge(crevices)and prey resources.We report on data collected from nighttime surveys undertaken in April-May 2014 on Barbados,West Indies,that focused on the distribution and abundance of the endemic Barbados leaf-toed gecko(Phyllodactylus pulcher)and the introduced tropical house gecko(Hemidactylus mabouia)along unlit coastal walls and among boulders in the grounds of a hotel resort.In contrast to patterns of displacement of native species by H.mabouia seen elsewhere,P.pulcher was more abundant than H.mabouia on coastal walls,whereas the latter was found in greater numbers using boulders at this site.Walls and boulders differed with regard to availability of diurnal refugia suitable for geckos,with the walls having high frequency of small crevices with openings<20 mm,and boulders offering very little cover other than the underside of the boulder itself.To investigate whether this niche separation was a result of differences in diurnal refuge use between the species,we conducted experimental trials in which geckos were allowed to select between refugia with different characteristics.Both species selected for narrower and warmer refugia,and refugia that had been previously occupied by the other species.These shared preferences for refugia type suggest that other factors underlie the niche separation observed in the field.In supporting high densities of P.pulcher,coastal walls could offer important secondary habitat by augmenting the natural cliff side habitat of this endemic gecko,a finding that could be exploited for the conservation of this candidate species for Critically Endangered classification.
