GROUP SIZE FACTORS AND GEOGRAPHIC VARIATION OF MORPHOMETRIC CORRELATION

Within-locality correlations among eight morphological traits of the fundatrix and among 15 morphological traits of the alate fundatrigeniae of the aphid Pemphigus populicaulis Fitch were examined for among-locality variation. A jackknife procedure revealed highly significant differences among correlation matrices representing 34 local samples from eastern North America. Most bivariate correlations also differed significantly among samples. Although very low correlations cannot differ, for moderate or strong correlations the average magnitude of correlation is not a good predictor of the degree of interlocality difference. Nearly half of the variation among localities is in the level of “overall correlation,” which is positively correlated with intralocality size variation. Despite significant differences among localities, spatial autocorrelation tests failed to reveal any significant geographic pattern in correlations. Monte Carlo experiments suggest that if geographic patterns in the correlations were of the same magnitude as those for the means of these traits, some of these patterns would have been detected. Factor analyses of the pooled within-locality correlation matrices, after oblique rotation to simple structure, reveal appendage and body-size factors for both alates and stem mothers. In general, correlations between traits with high loadings on the same factor differ among localities, whereas substantial correlations that do not vary geographically are between traits that are not well resolved by the factor analyses. It is hypothesized that the apparently random geographic differences in correlation are caused by chance differences in the mode of response to short-term selection. Geographic patterns in trait means are established by selection, but, because local population sizes are finite, similar response to selection occurs by diverse physiological or developmental mechanisms in different populations, just as replicate lines in artificial selection experiments may achieve the same response by diverse mechanisms. These diverse mechanisms of response will have diverse effects on genetic variance and covariance, causing correlation patterns to vary geographically. Several forces will oppose continued divergence of these patterns.     

光雾臭蛙的分布新纪录及地理变异

2009年8月在湖北省保康县五道峡自然保护区采到1种臭蛙类标本,与湖北省已有记录的绿臭蛙Odorrana margaretae明显不同,经与四川南江光雾山标本进行形态特征比较和DNA序列比对,鉴定为光雾臭蛙O.kuangwuensis。湖北省保康县光雾臭蛙体长大于模式产地标本;指序3、4、2、1,第2指与第1指几等长;关节下瘤显著,第2～4指具指基下瘤;4肢背面绿色与黑酱色横纹相间排列,横纹间无云状斑,股、胫部横纹3～4条,跗部和前臂2～3条。湖北省保康县五道峡与四川省南江县光雾山相距近5个经度,是否因地理隔离造成种群间的差异,有待进一步研究。     

GEOGRAPHIC AND TEMPORAL VARIATION IN MOTH CHEMICAL COMMUNICATION

In moth pheromone communication signals, both quantitative and qualitative intraspecific differences have been found across geographic regions. Such variation has generally been hypothesized to be due to selection, but evidence of genetic control of these differences is largely lacking. To explore the patterns of variation in pheromone signals, we quantified variation in the female sex pheromone blend and male responses of two closely related noctuid moth species in five different geographic regions for 2–3 consecutive years. We found significant variation in the ratios of sex pheromone blend components as well as in male response, not only between geographic regions but also within a region between consecutive years. The temporal variation was of a similar magnitude as the geographic variation. As far as we know, this is the first study reporting such temporal variation in moth chemical communication systems. The geographic variation seems to at least partly be controlled by genetic factors, and to be correlated with the quality of the local chemical environment. However, the pattern of temporal variation within populations suggests that optimization of the pheromonal signal also may be driven by within-generation physiological adjustments by the moths in response to their experience of the local chemical environment.     

ANATOMY AND AFFINITIES OF PENTHORUM

The genus Penthorum L. consists of two species of perennial herbs, P. sedoides of eastern North America and P. chinense of eastern Asia. Penthorum has long been considered intermediate between Crassulaceae and Saxifragaceae. An anatomical study of both species was undertaken to contribute to a better understanding of the relationships of these plants. Prominent anatomical features of Penthorum include: an aerenchymatous cortex and closely-spaced collateral vascular bundles of stems; one-trace unilacunar nodes; brochidodromous venation, rosoid teeth bearing hydathodes, and anomocytic stomata of leaves; angular vessel elements with many-barred scalariform perforation plates and alternate to scattered intervascular pits; thin-walled non-septate fiber-tracheids; abundant homocellular erect uniseriate and biseriate rays; and absence of axial xylem parenchyma. In general, Penthorum possesses neither the morphological nor the anatomical synapomorphies which define Crassulaceae, and features shared with Saxifragaceae are largely symplesiomorphous. Thus Penthorum is probably best classified in the monogeneric Penthoraceae.     

杉木种源胸径生长地理变异规律的研究

“ｋｒｉｇｅ”技术是空间内插稀疏观测资料的随机方法。本文应用该方法,对全国杉木种源试验５５个试验点的４３个共同种源的胸径生长结果进行地理变异分析。结果表明：“ｋｒｉｇｅ”空间内插技术能准确反映杉木种源胸径生长的地理变异规律,拟合优度达到９１．７％。用４３个种源中的３３个杉木种源胸径生长作为已知点预测剩余１０个杉木种源胸径生长,预测精度达９５．８５％,说明用“ｋｒｉｇｅ”技术研究杉木种源地理变异是可行的,也为种源区划提供了有力的新工具。     

GEOGRAPHIC VARIATION AND HETEROCHRONY IN TWO SPECIES OF COWRIES (GENUS CYPRAEA)

Geographic variation in the marine, Indo-Pacific cowry, Cypraea caputserpentis, involves clinal variations that parallel the ontogenetic development of adult shell characteristics. Cypraea caputdraconis, a closely related species endemic to Easter Island and Sala y Gómez, is morphologically similar to juvenile C. caputserpentis. Using multivariate measures of size and shape, I examine these patterns as a possible outcome of heterochrony, or changes in the timing of developmental events in ontogeny. Whorl-expansion rates of juvenile shells are significantly higher in C. caputdraconis when compared to C. caputserpentis and are negatively correlated with surface seawater temperatures among populations of C caputserpentis. High expansion rates, often associated with slow growth, result in a delay in the onset of lateral callus development and subsequent paedomorphosis. Ontogenetic trajectories calculated from growth series of adult and preadult shells indicate that paedomorphosis results from the combined effects of neoteny and post-displacement. Paedomorphosis among cowries may result from the advantages of larger body size relative to shell size under reduced predation intensities and associated increases in fecundity.     

GEOGRAPHIC VARIATION, FREQUENCY-DEPENDENT SELECTION, AND THE MAINTENANCE OF A FEMALE-LIMITED POLYMORPHISM

A central problem in evolutionary biology is to understand how spatial and temporal variation in selection maintain genetic variation within and among populations. Brown anole lizards ( Anolis sagrei ) exhibit a dorsal pattern polymorphism that is expressed only in females, which occur in diamond,bar, and intermediate diamond-bar morphs. To understand the inheritance of this polymorphism, we conducted a captive breeding study that refuted several single-locus models and supported a two-locus mode of inheritance. To describe geographic variation in morph frequencies, we surveyed 13 populations from two major islands in The Bahamas. Morph frequencies differed substantially between major islands but were highly congruent within each island. Finally, we measured viability selection on each island to test two hypotheses regarding the maintenance of the polymorphism: (1) that spatial variation in selection maintains variation in morph frequencies between islands, and (2) that temporal variation in selection across years maintains variation within islands. Although bar females had relatively lower survival where they were rare, our data do not otherwise suggest that selection varies spatially between islands. However, diamond-bar females were subject to positive frequency-dependent selection across years, and the relative fitness of bar and diamond females alternated across years. We propose that this polymorphism is maintained by temporal variation in selection coupled with the sheltering of alleles via a two-locus inheritance pattern and sex-limited expression.     

STRUCTURE AND AFFINITIES OF PROTOSTIGMARIA EGGERTIANA

Investigation of new, more or less complete specimens of Protostigmaria eggertiana reveals that it is a large, multilobed rooting structure produced at the base of a small arborescent lycopod. The trunk bears scars marking the point of attachment of leaves, and can be compared to the stem of Lepidodendropsis. In the largest specimens the root-bearing base is divided into about 13 lobes. In smaller, presumably younger specimens, fewer lobes are present. The roots are arranged on the lobes in series and orthostichies comparable to those of Isoetes. New observations on five- and six-lobed Isoetes plants reveal a closer correspondence between Protostigmaria and Isoetes than previously recognized; and support suspected homologies among many fossil and extant lycopsid rooting structures.     

GEOGRAPHIC VARIATION AND SEXUAL DIMORPHISM IN THE SKULL OF DALL'S PORPOISE, PHOCOENOIDES DALLI

Abstract: Two hundred and eighty-nine skulls of Dall's porpoises from the North Pacific Ocean, Sea of Japan, Sea of Okhotsk, and Bering Sea were investigated morphometrically. A clear pattern of geographic variation was found in overall size of the skull. In the North Pacific, overall skull size became gradually smaller eastward from the coast of Japan to the offshore eastern Pacific, and it became larger again off the coast of California. Specimens from the Sea of Japan-Okhotsk and Bering Sea had larger skulls than those from the central North Pacific. The distribution of primary productivity corresponds well with this pattern of geographic variation, suggesting that quantity of food might affect the overall size of Dall's porpoise skulls. By canonical discriminant analyses, about 70% (male) and 90% (female) of specimens of the Sea of Japan-Okhotsk population were distinguished from those of other populations. This agrees with the results of genetic studies.