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您的检索式：作者名="Jason T.Weir"
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| 1 | Description of the song of the Nilgiri Thrush(Zoothera [aurea] neilgherriensis) and song differentiation across the Zoothera dauma species complex显示文摘Background: Taxonomic treatment of the Zoothera dauma species complex is highly variable and has been hampered by the absence of song recordings for the Nilgiri Thrush(Zoothera [aurea] neilgherriensis).Methods: I obtained two recordings of the song of neigherriensis from southern Indian. Here I publish sonograms and analyze song recordings for all but one currently described taxon from the Eurasian portion of the geographic range of this species complex. Principal component analyses were used to investigate song differences between taxa.Results: The song of neigherriensis is a highly complex series of strophes remarkably similar to the song of the insular Zoothera major. Vocal analyses across the complex indicate four key groups of taxa differentiated in their songs:(1) simple flat whistled songs which include the northern aurea, toratugumi and the undescribed Taiwan population;(2) eastern populations of dauma(reported here for the first time) which sing like northern birds but with much broader bandwidth,(3) strongly down-slurred, thin whistles of tropical resident imbricata of Sri Lanka and horsfieldi of Indonesia, and(4) highly complex songs of Himalayan dauma, neilgherriensis and major.Conclusions: Zoothera dauma is unlikely to represent a single species given the simple singing populations from its eastern range and highly complex song from the Himalayan portion of its range. neilgherriensis should either be transferred from Zoothera aurea, where it is currently classified as a subspecies, and be placed as a subspecies within Z. dauma from the Himalayas or it should be recognized as a distinct species. Given the small number of songs available for analyses, I suggest the former course until it can be clearly demonstrated that neilgherriensis and Himalayan dauma are vocally distinct. | Jason T.Weir | 2018 | Avian Research2018，9，3： | 0 |
| 2 | No signature of selection on the C-terminal region of glucose transporter 2 with the evolution of avian nectarivory显示文摘Background:Flying birds,especially those that hover,need to meet high energetic demands.Birds that meet this demand through nectarivory face the added challenges of maintaining homeostasis in the face of spikes in blood sugar associated with nectar meals,as well as transporting that sugar to energetically demanding tissues.Nectarivory has evolved many times in birds and we hypothesized that the challenges of this dietary strategy would exert selective pressure on key aspects of metabolic physiology.Specifically,we hypothesized we would find convergent or parallel amino acid substitutions among different nectarivorous lineages in a protein important to sensing,regulating,and transporting glucose,glucose transporter 2(GLUT2).Methods:Genetic sequences for GLUT2 were obtained from ten pairs of nectarivorous and non-nectarivorous sister taxa.We performed PCR amplification of the intracellular C-terminal domain of GLUT2 and adjacent protein domains due to the role of this region in determination of transport rate,substrate specificity and glucosensing.Results:Our findings have ruled out the C-terminal regulatory region of GLUT2 as a target for selection by sugar-rich diet among avian nectarivores,though selection among hummingbirds,the oldest avian nectarivores,cannot be discounted.Conclusion:Our results indicate future studies should examine down-stream targets of GLUT2-mediated glucosensing and insulin secretion,such as insulin receptors and their targets,as potential sites of selection by nectarivory in birds. | Alexander M.Myrka Tooba Shah Jason T.Weir Kenneth C.Welch Jr. | 2020 | Avian Research2020，11，4： | 0 |
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