The dynamics of natural selection and vicariance in the Dominican anole: patterns of within-island molecular and morphological divergence

The larger islands of the Lesser Antilles are ecologically and geologically complex and are inhabited by single, but morphologically variable, Anolis species. Although earlier work has indicated that a large part of the morphological variation in Anolis oculatus from Dominica can be attributed to selection, a history of recurrent volcanic activity over the last few million years suggests that vicariance may have also played a significant role. We report a study of variation in the cytochrome b gene of mitochondrial DNA across the island to address this issue. We uncovered a very high degree of polymorphism, with an overall gene diversity of 0.97 and a nucleotide diversity of 0.04. Sequences, on average, differ by 3.82% and the maximum pairwise divergence (corrected for multiple hits) is 9.29%. Most haplotypes are restricted to single localities (a pattern not changed by increasing the sample size). Phylogenetic analysis revealed the presence of two distinct lineages on the island with strong phylogeographic structure. One of these is geographically restricted to a relatively small part of the central Caribbean coast. Sublineages were also discernible within the other more widely distributed lineage, but resolution within and support for these sublineages was poor. The phylogeographic pattern is not congruent with generalized body shape and scalation, but is significantly correlated with color pattern. Even when correcting for this lineage effect with partial Matrix correspondence tests, the relationship between color pattern and vegetation is reaffirmed, suggesting that although both vicariance and selection have played a role in the morphological differentiation of this species, selection for current environmental conditions has been more important. We discuss the causes of the phylogeographic structure in light of the volcanic history of the island and highlight the exceptional instance of congruence between all morphological character systems and lineage boundaries, which occurs at the transition between the northern and southern Caribbean ecotypes.     

Prey Luring Coloration of A Nocturnal Semi‐Aquatic Predator

Body coloration serves a variety of purposes in animals. Diurnal and nocturnal predators such as spiders may use their body coloration to lure prey. We predicted here that the white patches on the forelegs on females of the nocturnal semi‐aquatic spider Dolomedes raptor lure prey, explaining why they are primarily displayed when the spider forages along the water edge. To test our prediction, we developed a color vision model assessing whether the patches are visible to pygmy grasshoppers, the spider's primary prey. We conducted a field experiment using cardboard dummies that resemble D. raptor in size, shape, and color, but with half of them lacking leg patches, and we staged interactions between pygmy grasshoppers and D. raptor with and without leg patches in a greenhouse. We found the white patches to be visible to grasshoppers. The dummies with white patches attracted more grasshopper prey than the dummies without the patches. Moreover, grasshoppers were more attracted to spiders when their white patches were present. Our results supported the hypothesis that the white patches of D. raptor lure prey. Our findings, nevertheless, could not be explained as the spider's body coloration acting as a sensory trap but it should not be ruled out. More studies on a wider range of predators and prey will give more meaningful insights into the co‐evolution of predatory lures and prey sensory modalities.     

Evolution after Whole-Genome Duplication: Teleost MicroRNAs

MicroRNAs (miRNAs) are important gene expression regulators implicated in many biological processes, but we lack a global understanding of how miRNA genes evolve and contribute to developmental canalization and phenotypic diversification. Whole-genome duplication events likely provide a substrate for species divergence and phenotypic change by increasing gene numbers and relaxing evolutionary pressures. To understand the consequences of genome duplication on miRNA evolution, we studied miRNA genes following the teleost genome duplication (TGD). Analysis of miRNA genes in four teleosts and in spotted gar, whose lineage diverged before the TGD, revealed that miRNA genes were retained in ohnologous pairs more frequently than protein-coding genes, and that gene losses occurred rapidly after the TGD. Genomic context influenced retention rates, with clustered miRNA genes retained more often than nonclustered miRNA genes and intergenic miRNA genes retained more frequently than intragenic miRNA genes, which often shared the evolutionary fate of their protein-coding host. Expression analyses revealed both conserved and divergent expression patterns across species in line with miRNA functions in phenotypic canalization and diversification, respectively. Finally, major strands of miRNA genes experienced stronger purifying selection, especially in their seeds and 3′-complementary regions, compared with minor strands, which nonetheless also displayed evolutionary features compatible with constrained function. This study provides the first genome-wide, multispecies analysis of the mechanisms influencing metazoan miRNA evolution after whole-genome duplication.     

Life History of the Whitefly Predator Nephaspis oculatus (Coleoptera: Coccinellidae) at Six Constant Temperatures

Nephaspis oculatus (Blatchley) is a predator of whiteflies including Bemisia tabaci (Gennadius) and B. argentifolii Bellows and Perring. The usefulness of this and other coccinellid predators of whiteflies could be improved by better information on responses to different temperatures experienced in the field. We reared N. oculatus from egg to adult in incubators at six constant temperatures and observed a linear relationship between developmental time and temperature for all preimaginal lifestages through all but the highest temperatures (33°C). Four larval instars were observed, although a significant proportion of third instar larvae molted directly to the pupal stage at 29°C and above. Complete life table data were obtained at all temperatures except 33°C. Survivorship was greatest over all immature stages at 26°C and finite and intrinsic rates of increase were highest at this temperature. Although 26°C appeared to be the optimum temperature for population growth, estimated rates of increase at all temperatures tested above 20°C were within 75% of the maximum, indicating that the beetle can perform well within the temperature range usually found in greenhouses.     

东北地区乳菇属的初步研究

本文报道了东北地区乳菇属(Lactarius)的29种,其中包括新种2个,长白乳菇(L.chanbainensis Y.Wang et Xie sp.nov.)温泉乳菇(L.wenquanensis Y.Wang et Xie sp.nov.);国内新记录种5个:茶绿乳菇[L.necator(Pers.ex Fr.)Farst.],条纹乳菇[L.oculatus(Peck)Burl.],变红乳菇[L.acris(Bolt.ex Fr.)Gray],复生乳菇(L.repraesentaneus Britz.)和点柄乳菇(L.maculatus Burl.)。新种有汉文和拉丁文描述以及形态、显微构造图;国内新记录种有汉文描述。     

滇、桂地区刺翼蚱科二新种记述(直翅目,蚱总科)

记述采自云南红河地区及广西南宁地区蚱总科昆虫2新种,即滇桂瘤蚱Thoradonta dianguiensis sp.nov.,断隆优角蚱Eucriotettix interrupta sp.nov..模式标本保存在陕西师范大学动物研究所标本室.     

大优角蚱卵块外型的数学模型研究及其生态学意义

【目的】探究大优角蚱Eucriotettix grandis独特的卵块形态的生态学意义。【方法】在大量野外调查大优角蚱卵块生态学特征的基础上, 通过对卵块图片的三维数据点进行截面线抽取, 获得卵块截面曲线的拟合方程, 并用线条拟合法建立相应的数学模型。依据拟合曲线的曲率图和二阶导数值图对数据拟合曲线的几何特性进行分析。【结果】大优角蚱多以完整卵块的形式产卵, 卵块为约六边形的橘子瓣状结构, 且卵块顶部有一明显的半球形凹槽, 底部则中间略隆起。利用线条拟合理论, 构造出既能够有效满足拟合优度, 又能够满足光滑度的核函数, 通过对函数取值得到模型曲线非常近似拟合于真值曲线。【结论】凹槽很可能是便于存水, 保持卵块的湿润, 利于卵的存活和孵化; 棱角有利于缓解卵块的远距离滚动和破散, 紧密结合的卵块结构利于卵的保温保湿。