朱雀类和朱鹀的分子系统发生分析

基于细胞色素b基因对13种朱雀Carpodacus spp.进行了系统发育分析,并结合核基因对单型属朱鹀属Urocynchramus的系统分类地位做了进一步探讨.研究发现朱雀属为一多系群,其中Carpodacus nipalensis和Leucosticte tephrocotis较朱雀属的其它成员有更近的亲缘关系.本文研究结果还进一步支持了朱鹀应该独立成为一个科的观点.     

Leukocyte Profiles in Wild House Finches with and without Mycoplasmal Conjunctivitis,a Recently Emerged Bacterial Disease

Leukocyte profiles (relative numbers of white blood cell types) have been used by a growing number of ecological studies to assess immune function and stress in wild birds. House Finches (Carpodacus mexicanus) in eastern North America are susceptible to an eye disease caused by the bacterium Mycoplasma gallisepticum, providing the opportunity to examine whether leukocyte profiles are associated with infection status and other host characteristics. In this study, we compared blood smears from 297 wild House Finches with and without conjunctivitis to examine whether leukocyte profiles were associated with the presence and severity of mycoplasmal conjunctivitis. We also evaluated the influence of age, sex, and molt on leukocyte profiles in both diseased and nondiseased birds. Of 243 House Finches of known age and sex sampled, 30% showed clinical signs of mycoplasmal conjunctivitis. House Finches with conjunctivitis had significantly higher heterophil to lymphocyte (H/L) ratios and harbored greater numbers and proportions of heterophils and monocytes than nondiseased birds. Leukocyte profiles of noninfected birds did not differ significantly with respect to sex, but young birds had significantly greater numbers of lymphocytes and total white blood cells than adults. Molting birds had significantly more eosinophils than nonmolting birds. Finally, House Finches with the most severe outward signs of conjunctivitis showed the most dramatic leukocyte changes relative to noninfected individuals, and increasing H/L ratios and monocytes in diseased birds were paralleled in a subset of birds that were recaptured during the study period. These results are consistent with patterns observed in domestic poultry and suggest that understanding patterns of leukocyte differentials in this host-pathogen system could improve our understanding of innate immunity and infectious disease risk in other wild passerines.     

Nemerteans of the Great Barrier Reef 3. Anopla Heteronemertea (Lineidae)

Nine species of lineid heteronemerteans are recorded from the Great Barrier Reef province of Australia. Six of these are new species, including four new genera, and are fully described and illustrated. These are Aetheorhynchus actites gen. et sp. nov. , Bennettiainsularis gen. et sp. nov., Cerebratulus magnetkus sp. nov., Colemania albulus gen. et sp. nov., Mkrura tridacnae sp. nov. and Quasilineus pulcherrimus gen. ct sp. nov. Lineus tricuspidatus (Quoy & Gaimard) is re-established, illustrated and described. Gorgonorhynchus repens Dakin & Fordham and Parborlasia hutchingsi Gibson have been fully described elsewhere, but a full list of known locations is provided.     

褐头朱雀和藏雀的研究现状

褐头朱雀(Carpodacus sillemi)与藏雀(C.roborowskii)均是我国的特有鸟类,也互为亲缘关系最近的姊妹种,它们自发现命名以来长期属于了解非常有限的种类,褐头朱雀更是全世界最罕为人知的现生鸟类之一.目前,与褐头朱雀及藏雀有关的研究报道和资料很少.根据已有的文献,结合在野外实地观察所获取的资料,对...     

青岛近岸海域马粪海胆摄食的实验生态学研究

对采自青岛近岸海域的马粪海胆从其对各种饵料的选择和摄食吸收、温度与自身湿重对其摄食率的影响以及摄食活动特征等方面进行实验生态学研究。结果表明 ,马粪海胆在多种海藻并存的情况下 ,对海带及裙带菜等褐藻具明显的选择性 ,对石花菜及孔石莼等藻类的喜好性较差 ,但在食物匮乏条件下 ,马粪海胆的食谱则变得相当广泛。马粪海胆对裙带菜及海带的摄食率均明显高于孔石莼 ,但其对孔石莼的饵料吸收率则高于海带及裙带菜。马粪海胆的摄食受温度条件及自身湿重的影响 ,温度偏离适宜范围对摄食有抑制作用 ,日摄食率与湿重呈显著的指数下降关系 ,摄食率与湿重、温度因子可建立具较高可靠性的指数回归模型。马粪海胆对食物的口面吸附与对其摄食密切相关 ,其摄食活动与湿重呈显著的指数下降关系 ,而与排便活动呈显著的正相关 ,随湿重增加排便活动虽呈下降趋势 ,但未达显著水平。自然光照条件下马粪海胆的夜间摄食强度通常高于日间 ,但在全遮盖的无光照条件下这种昼夜摄食差异则变得不显著 ;对摄食活动的连续观测表明马粪海胆的摄食活动受光强变化的影响 ,其摄食活动的高峰出现在光强减弱的早间及傍晚 ,而日间的强光照环境会抑制其摄食活动     

Sickness behaviour acting as an evolutionary trap? Male house finches preferentially feed near diseased conspecifics

Host behaviour towards infectious conspecifics is a crucial yet overlooked component of pathogen dynamics. Selection is expected to favour individuals who can recognize and avoid infected conspecifics in order to reduce their own risk of infection. However, evidence is scarce and limited to species employing chemical cues. Here, we experimentally examine whether healthy captive house finches (Carpodacus mexicanus) preferentially forage near a same-sex, healthy conspecific versus one infected with the directly transmissible pathogen Mycoplasma gallisepticum (MG), which causes lethargy and visible conjunctivitis. Interestingly, male house finches strongly preferred feeding near diseased conspecifics, while females showed no preference. This sex difference appeared to be the result of lower aggression rates in diseased males, but not in females. The reduced aggression of diseased males may act as an ‘evolutionary trap’ by presenting a historically beneficial behavioural cue in the context of a new environment, which now includes a recently emerged, potentially fatal pathogen. Since MG can be directly transmitted during feeding, healthy males may inadvertently increase their risk of contracting MG. This behaviour is likely to significantly contribute to the continued persistence of MG epidemics in wild populations.     

Evaluation of two approaches to genotyping major histocompatibility complex class I in a passerine-CE-SSCP and 454 pyrosequencing

Genes of the highly dynamic major histocompatibility complex (MHC) are directly linked to individual fitness and are of high interest in evolutionary ecology and conservation genetics. Gene duplication and positive selection usually lead to high levels of polymorphism in the MHC region, making genotyping of MHC a challenging task. Here, we compare the performance of two methods for MHC class I genotyping in a passerine with highly duplicated MHC class I genes: capillary electrophoresis-single-strand conformation polymorphism (CE-SSCP) analysis and 454 GS FLX Titanium pyrosequencing. According to our findings, the number of MHC variants (called alleles for simplicity) detected by CE-SSCP is significantly lower than detected by 454. To resolve discrepancies between the two methods, we cloned and Sanger sequenced a MHC class I amplicon for an individual with high number of alleles. We found a perfect congruence between cloning/Sanger sequencing results and 454. Thus, in case of multi-locus amplification, CE-SSCP considerably underestimates individual MHC diversity. However, numbers of alleles detected by both methods are significantly correlated, although the correlation is weak (r = 0.32). Thus, in systems with highly duplicated MHC, 454 provides more reliable information on individual diversity than CE-SSCP.