WHY DO PARASITIC CUCKOOS HAVE SMALL BRAINS? INSIGHTS FROM EVOLUTIONARY SEQUENCE ANALYSES

Brain size is under many opposing selection pressures. Estimating their relative influence and reconstructing the brain's evolutionary history have, however, proved difficult. Here, we confirm the suggestion that the brain of brood parasitic cuckoos is smaller in relation to their body weight than that of nonparasitic cuckoo species. Two hypotheses explaining reductions in brain size are tested, using phylogenetically controlled correlations and evolutionary pathway analyses. In a novel approach, the pathway models are combined to build the most likely evolutionary sequence of trait changes correlating with changes in brain size. Brain size changed before brood parasitism, followed by a shift toward less-productive habitats and an increase in migration. This sequence shows that brain size was not reduced as a consequence of a loss of cognitive skills related to chick provisioning, and it offers no support for the hypothesis that an increase in energetic demands or a reduction in energy availability selected for a reduction of brain size. Instead, the sequence suggests that the reduction in energetic demands due to the smaller brain size and parasitic breeding strategy may have enabled parasitic cuckoos to colonize new niches.     

A STUDY OF THE GENUS POLΥOMMATUS LATREILLE (LEPIDOPTERA, LYCAENIDAE) FROM CHANGBAI MOUNTAINS,WITH A NEWLY RECORDED SPECIES FROM CHINA

记述长白山区眼灰蝶属4种,其中兹眼灰蝶Polyommatus tsvetaevi (Kurentzov,1970)为中国新纪录种,编制分种检索表,提供成虫照片和外生殖器特征图.因阿眼灰蝶Polyommatus amanda和酷眼灰蝶Polyommatus semiargus在长白山的亚种名均为amurensis,因此,amurensis Tutt,1909就成为amurensis(Staudinger,1892)的次同名,需要提出替代名Polyommatus semiargus changbaishanensis nom.nov.     

RECONNECTING CELL AND ANIMAL LINEAGES: WHAT DO CELL LINEAGES TELL US ABOUT THE EVOLUTION AND DEVELOPMENT OF SPIRALIA?

Cell lineage studies in the clade Eutrochozoa, and especially the Spiralia, remains a rich and relatively untapped source for understanding broad evolutionary developmental problems; including (1) the utility of cell timing formation for phylogenetic hypotheses; (2) the evolution of cell timing changes and its relation to heterochronic patterns; (3) stereotypy or lack thereof in rates of change of cell growth during evolution and its relation to both evolutionary history and current usage; and (4) how mosaic cleavage timing variation may be expected to differ from other groups. A compilation of available cell timing information was made from previous studies where each division was explicitly followed and the total number of cells followed was greater than 24. From that compilation, we performed a series of heuristic and quantitative analyses, including a phylogenetic analysis using cell timing data as characters and analyses of timing variation across all taxa. Our results show that: (1) cell lineage data reconstructs a phylogenetic hypothesis that has similarities, especially among the Mollusca. to the patterns found in morphological and molecular analyses; (2) the mesentoblast (4d) is a unique cell compared to other cell in that it speeds up and slows down relative to other cells in taxa with both unequal and equal cell sizes; (3) some cells that form in the same quartet at the same point in the cell lineage hierarchy have much lower variations than analogous other cells, arguing for architectural constraint or stabilizing selection acting on those cells; and (4) although variation in cell timing generally increases during development, timing of formation of progeny cells in the first quartet has lower variation than the parent cells, arguing that some regulation-like behavior might be present.     

POSTMENOPAUSAL MOTHERHOOD: IMMORAL,ILLEGAL? A CASE STUDY

The paper explores the ethics of post-menopausal motherhood by looking at the case of Adriana Iliescu, the oldest woman ever to have given birth (so far). To this end, I will approach the three most common objections brought against the mother and/or against the team of healthcare professionals who made it happen: the age of the mother, the fact that she is single, the appropriateness of her motivation and of that of the medical team.     

WHAT DO WE KNOW ABOUT THE HERITABILITY OF DEVELOPMENTAL INSTABILITY? ANSWERS FROM A BAYESIAN MODEL

In spite of over half a century of research, little is known about the genetic basis of developmental instability (DI). The estimation of the heritability of DI is seriously hampered by the fact that fluctuating asymmetry-FA, that is, the observable outcome of DI-only poorly reflects DI. This results in an underestimation of the heritability of DI. Current methods transforming heritabilities in FA into those of DI fail to take all sources of variation into account and yield incorrect confidence bands that are usually based on unrealistic assumptions. Therefore, a Bayesian latent variable model is developed and explored. Simulations show that with sample sizes currently applied in empirical studies, extremely wide posterior distributions are obtained and data do not allow to distinguish between high (0.5) and low (0.1) heritabilities of DI at all. Even sample sizes of 5000 result in very wide posteriors in many cases. Furthermore, for smaller samples (250 and 1250), up to 70% of the estimates of the heritability of DI were below the mean expected value because of the high skewness of its distribution. Knowing that in only one study, sample sizes were above 5000, there is a need for larger studies to evaluate the evolutionary potential of DI. Designs with relatively low numbers of sires (1-2% of total number of offspring) appear most efficient. Because such high sample sizes are hard to obtain for many study organisms, more insights are required about how data from different traits can be combined in a single analysis. In addition, new designs and methods, such as QTL analyses and micro-array techniques, should be applied to gain a better understanding of the genetic basis of DI.     

A STUDY OF TRIPLOID AND 3 X – 1 ANEUPLOID PLANTS IN THE GENUS GOSSYPIUM

Cytological comparisons were made of triploid and 3x – 1 plants of Gossypium hirsutum (haplo 17 and 18) X G. aridum, G. armourianum, G. harknessii, and G. raimondii. Tests and observations led to these conclusions: (1) Chromosome conjugation varied significantly from plant to plant and date to date within plants. (2) The D genome chromosomes of G. hirsutum are closer in homology to G. raimondii than to the other species tested. (3) The chromosomes of G. aridum, have closer homology to the A genome of G. hirsutum than do the chromosomes of the other D species tested. (4) The D genome of G. hirsutum has a small translocation as compared to the genomes of the four D species studied.     

PERSPECTIVE: FROM MUTANTS TO MECHANISMS? ASSESSING THE CANDIDATE GENE PARADIGM IN EVOLUTIONARY BIOLOGY

The generation of mutants in model organisms by geneticists and developmental biologists over the last century has occasionally produced phenotypes that are startlingly reminiscent of those seen in other species. Such extreme mutations have generally been dismissed by evolutionary geneticists since the \"modern synthesis\" as irrelevant to adaptation and speciation. But only in recent years has information on the molecular bases of mutant phenotypes become widely available, and thus work on testing the relevance of such extreme mutations to the generation of phylogenetic diversity has just begun. Here we evaluate whether evolutionary mimics are, in fact, useful for pinpointing the genetic differences that distinguish morphological variants generated during evolution. Examples come from both plants and animals, and range from intraspecific to interordinal taxonomic ranges. The use of mutationally defined candidate genes to predict evolutionary mechanisms has so far been most fruitful in explaining intraspecific variants, where it has been effective in both plants and animals. In several cases these efforts were facilitated or supported by parallel results from quantitative trait loci studies, in which natural alleles controlling continuous variation in developmental model organisms were mapped to mutationally defined genes. However, despite these successes the approach's utility seems to rapidly decay as a function of phylogenetic distance. This suggests that the divergence of developmental genetic systems is great even in closely related organisms and may become intractable at larger distances. We discuss this result in the context of what it teaches us about development, the future prospects of the candidate gene approach, and the historical debate over process in micro- and macroevolution.     

FROM WHERE DO LAND SNAILS OBTAIN THE CHEMICALS TO BUILD THEIR SHELLS?

Monthly changes in the oxygen and carbon isotope compositionof the shells of two annual species from Israel were investigatedto elucidate the sources of the oxygen, carbon and calcium fromwhich the shell is built. The observations showed that the oxygen,carbon and probably also the calcium are derived from the waterthat the snails either absorb through their skin or drink fromthe upper layers of the soil. There are seasonal fluctuations in both the oxygen and carboncomposition of the shell. Fluctuations in oxygen isotope compositionprobably result from the fact that deeper soil water (richerin ¹⁸0) rises to the surface during the summer months. It issuggested that fluctuations in shell carbon isotope are relatedto the seasonal effects of the metabolic activities of the ambientvegetation (such as spring rejuvenation of annual angiosperms)and the summer bloom of soil bacteria. (Received 4 May 1982;     

A NEW SPECIES OF THE GENUS SINOCΥCLOCHEILUS (CYPRINIFORMES, CYPRINIDAE) FROM GUANGXI, CHINA

2011年7月,在中国广西隆林县天生桥镇红水河水系一洞穴采集到2尾标本.经鉴定为金线鲃属Sinocyclocheilus 1新种,曲背金线鲃Sinocyclocheilns flexuosdorsalis sp.nov..新种背鳍分支鳍条8根,头背部交界处隆起,具前突状结构,并向下贴近顶骨.吻较长.这些特征可与属内其他种相区别.     

DOES NICHE CONSERVATISM PROMOTE SPECIATION? A CASE STUDY IN NORTH AMERICAN SALAMANDERS

Recent speciation research has generally focused on how lineages that originate in allopatry evolve intrinsic reproductive isolation, or how ecological divergence promotes nonallopatric speciation. However, the ecological basis of allopatric isolation, which underlies the most common geographic mode of speciation, remains poorly understood and largely unstudied. Here, we explore the ecological and evolutionary factors that promote speciation in Desmognathus and Plethodon salamanders from temperate eastern North America. Based on published molecular phylogenetic estimates and the degree of geographic range overlap among extant species, we find strong evidence for a role for geographic isolation in speciation. We then examine the relationship between climatic variation and speciation in 16 sister-taxon pairs using geographic information system maps of climatic variables, new methods for modeling species' potential geographic distributions, and data on geographic patterns of genetic variation. In contrast to recent studies in tropical montane regions, we found no evidence for parapatric speciation along climatic gradients. Instead, many montane sister taxa in the Appalachian Highlands inhabit similar climatic niches and seemingly are allopatric because they are unable to tolerate the climatic conditions in the intervening lowlands. This temporal and spatial-ecological pattern suggests that niche conservatism, rather than niche divergence, plays the primary role in promoting allopatric speciation and montane endemism in this species-rich group of vertebrates. Our results demonstrate that even the relatively subtle climatic differences between montane and lowland habitats in eastern North America may play a key role in the origin of new species.     

A NEW SPECIES OF THE GENUS DICTΥOPHARINA MELICHAR (HEMIPTERA, FULGOROIDEA, DICTYOPHARIDAE) FROM CHINA

记述采自中国海南、贵州、广东的短象蜡蝉属Dictyopharina Melichar(半翅目,蜡蝉总科,象蜡蝉科,象蜡蝉亚科)1新种,即六突短象蜡蝉D.hexasaca sp.nov..编制了短象蜡蝉属分种检索表,提供了新种的鉴别特征图.新种模式标本保存于贵州大学昆虫研究所.     

A STUDY ON THE GENUS PΥRGOCORΥPHA ST(A)L WITH DESCRIPTION OF ONE NEW SPECIES FROM CHINA (ORTHOPTERA,TETTIGONOIDEA, CONOCEPHALIDAE)

对中国锥头螽属Pyrgocorypha St(a)l,1873的种类进行了研究,并记述了1新种和2新组合,新组合为中国新纪录种.模式标本均保存在中国科学院上海昆虫博物馆.