尼日利亚热带雨林池塘中茄氏旗鳉的食性

本文逐月研究了尼日利亚Mfangmfangpond中茄氏旗鳉全年的食性。其食谱按优势多寡出现的次序分别是陆生无脊椎动物、大型植物、水生无脊椎动物、小型甲壳动物、沙粒和藻类。我们将膜翅目、鞘翅目和双翅目昆虫作为其食性的次级项,而全年都出现的有机体碎屑作为初级项。雄鱼较雌鱼捕食了更多的陆生无脊椎动物。茄氏旗在雨季有16项食物组成,但旱季只有7项。就相对重要性而言,陆生和水生无脊椎动物在旱季更大,而大型植物碎屑、小型甲壳动物、沙粒和藻类则在雨季更大。成鱼较幼鱼更多地以外源性无脊椎动物为食。雌鱼较雄鱼有更强的觅食能力;同样,成鱼较幼鱼的觅食能力强得多.     

Phylogenetic relationships of African killifishes in the genera Aphyosemion and Fundulopanchax inferred from mitochondrial DNA sequences

We have analyzed the phylogenetic relationships of 52 species representing all defined species groups (J. J. Scheel, 1990, Atlas of Killifishes of the Old World, 448 pp.) of the African aplocheiloid fish genera Aphyosemion and Fundulopanchax in order to examine their interrelationships and to reveal trends of karyotypic evolution. The data set comprised 785 total nucleotides from the mitochondrial 12S rRNA and cytochrome b genes. The molecular-based topologies analyzed by both maximum parsimony and neighbor-joining support the monophyly of most previously defined species groups within these two killifish genera. The genus Aphyosemion is monophyletic except for the nested position of Fundulopanchax kunzi (batesi group; subgenus Raddaella) within this clade, suggesting that this taxon was improperly assigned to Fundulopanchax. The remaining Fundulopanchax species sampled were supported as being monophyletic in most analyses. Relationships among the species groups in both genera were not as strongly supported, suggesting that further data will be required to resolve these relationships. Additional sampling from the 16S rRNA gene allowed further resolution of relationships within Fundulopanchax, more specifically identifying the nonannual scheeli group as the basal lineage of this otherwise annual genus. Chromosomal evolution within Aphyosemion has been episodic, with the evolution of a reduced n = 9-10 metacentric complement having occurred in multiple, independent lineages. Polarity of chromosomal reductions within the elegans species group appears to support previous hypotheses concerning mechanisms of karyotypic change within the genus Aphyosemion.     

The behavior of the African killifish,Aphyosemion gardneri: normative studies

Synopsis The behaviors of maleAphyosemion gardneri observed during interactions with female and maleA. gardneri are described. First order transition matrices based on data collected during these interactions were used to construct behavioral flow diagrams. These flow diagrams show that sequences of sexual behaviors are less variable than sequences of aggressive behaviors. The position of acts in a typical sequence may be used in determining the level of activation of the behavioral system associated with those acts. Complexity and energy expenditure of behaviors tends to increase within sequences.     

Mitochondrial DNA phylogeny of West African aplocheiloid killifishes (Cyprinodontiformes, Aplocheilidae)

African killifishes (Cyprinodontiformes, Aplocheilidae) historically associated with the genus Aphyosemion occur in two geographically distinct regions. One assemblage from far West Africa has been previously shown to be monophyletic and not closely related to the remaining eastern species of Aphyosemion (W. J. Murphy and G. E. Collier, 1997, Mol. Biol. Evol. 14, 790-799). This is supported by further analysis of mitochondrial DNA sequences from 19 species from 21 different localities, representing 19 of the putative 22 species of this western group. Phylogenetic analyses of these data corroborate the monophyly and sister-group relationship of two distinct groups of taxa: Callopanchax and Scriptaphyosemion. Many of the relationships within Scriptaphyosemion suggest that these taxa may have radiated within a short period of time relative to the rate of substitutions within these sequences. A third, and possibly paraphyletic group of species, Archiaphyosemion, is suggested to be the sister taxon to the first two groups. These three groups are elevated to generic rank and together represent the sister group to the genus Epiplatys. Biogeographic inference suggests that the ancestors of this group diversified westward through upland habitat and have only relatively recently entered the lowland habitats in which Scriptaphyosemion and Callopanchax have diversified, with the latter genus reacquiring a suite of traits collectively referred to as annualism.     

Geographic variability of flower colour inCrocus scepusiensis (Iridaceae)

The distribution of four variants for flower colour ofCrocus scepusiensis in the northern part of the Western Carpathians is described. The frequency of white stigmata morphs declines from east to west. In the center of the area stigmata colour morphs show strikingly patchy distribution. White perianth morphs usually occur at low frequencies and their distribution with minor exceptions is restricted to the central part of the area, where patchy distribution of the morphs is a rule. These distribution patterns suggest that the founder effect has played a major role in determining the genetic composition of individual populations. The cline for stigmata colour may also be explained by the dynamics of population expansion. No influence of selection can be demonstrated, but the association between perianth and stigmata colour, and the excessively low frequency of white perianth morphs may imply that the polymorphisms are not selectively neutral.     

Carotenoids of the pupae of the Large White butterfly (Pieris brassicae) and the Small White butterfly (Pieris rapae)

The light cues received by the larvae of Pieris brassicae which determine diapause can also influence the carotenoid distribution (and hence the colour) in the epidermis and cuticle of the diapausing pupae. Irrespective of background or light cues received during the "sensitive period" of the pharate pupa, these diapausing pupae are coloured green. They then contain more than double the concentration of carotenoids in their epidermis than the non-diapausing pupae. This green colour can be somewhat modified by switching the full grown larvae to long day regimes immediately after feeding ceases.
The Large White and Small White butterfly each has a characteristic carotenoid storage pattern, which can be demonstrated by feeding the larvae on portions of the same cabbage leaves. The braconid parasite Apanteles glomeratus mirrors the carotenoids in its host.     

Relationship between age and colour of hatched eggshells of Ochlerotatus vigilax (Skuse) (Diptera: Culicidae) on an Australian saltmarsh

Abstract The presence of aedine mosquito eggshells in soil has recently been used to delineate oviposition patterns in coastal wetlands. However, the colour of eggshells may reveal information about the oviposition activity of mosquitoes that is not evident from the density and distribution of eggshells alone. This study describes the rate of colour change of newly hatched eggshells of Ochlerotatus (Ochlerotatus) vigilax , the common saltmarsh mosquito. In March 1996, eggshells were buried in soil of five mosquito-breeding sites on Kooragang Island, NSW. Eggshells were graded by colour using Munsell^® soil-colour charts. Seventy-five percent of newly hatched eggshells were black and 25% were dark brown in colour. Black eggshells faded quickly to lighter shades of brown, so that none were recovered 20 months after commencement of the study. Eggshells faded to a median of dark brown after 13 months and medium brown after 2 years. In another study, significant differences in colour frequency between existing saltmarsh and two recently created oviposition sites were found; the latter site being characterised by numerous black and dark-brown eggshells and very few light-brown eggshells. The results suggest that active and inactive oviposition sites may be identified using the frequency distribution of eggshell colours based on large numbers of eggshells, whereas the colour of individual eggshells only coarsely reflects age since eclosion.     

Identification, morphometries and cytogenetics of green geckos (Phelsuma) from Praslin, Seychelles (with notes on P. longinsulae, Mahé)

The three species of green geckos (Phelsuma) on the granitic Seychelles can be identified by colour pattern, snout shape and the occurrence of keeled belly scales. There is no difference in chromosome number (2n=S6) between species but multivariate morphometries analysis, based on body proportions and scalation, can distinguish between the species on Praslin Island.     

Non-random association of opsin alleles in wild groups of red-bellied tamarins (Saguinus labiatus) and maintenance of the colour vision polymorphism

The remarkable X-linked colour vision polymorphism observed in many New World primates is thought to be maintained by balancing selection. Behavioural tests support a hypothesis of heterozygote advantage, as heterozygous females (with trichromatic vision) exhibit foraging benefits over homozygous females and males (with dichromatic vision) when detecting ripe fruit on a background of leaves. Whilst most studies to date have examined the functional relevance of polymorphic colour vision in the context of foraging behaviour, alternative hypotheses proposed to explain the polymorphism have remained unexplored. In this study we examine colour vision polymorphism, social group composition and breeding success in wild red-bellied tamarins Saguinus labiatus. We find that the association of males and females within tamarin social groups is non-random with respect to colour vision genotype, with identified mating partners having the greatest allelic diversity. The observed distribution of alleles may be driven by inbreeding avoidance and implies an important new mechanism for maintaining colour vision polymorphism. This study also provides the first preliminary evidence that wild trichromatic females may have increased fitness compared with dichromatic counterparts, as measured by breeding success and longevity.     

Natural selection for apostasy and crypsis acting on the shell colour polymorphism of a mangrove snail, Littoraria filosa (Sowerby) (Gastropoda: Littorinidae)

Littoraria filosa (Sowerby) is a member of the L. scabra group, found amongst the foliage of mangrove trees in northern Australia. The colour of the shell is polymorphic, showing two discrete ground colours, either yellow or orange-pink, with a variable degree of superimposed brown patterning. At a site on Magnetic Island, northern Queensland, colour frequencies of small snails were similar on different backgrounds. Amongst larger shells yellows were more frequent on Avicennia trees with abundant foliage, and browns on relatively bare trees, suggesting that visual selection for crypsis occurred. There was no evidence of substrate selection by the morphs. Yellow shells were cooler than brown shells, but differences in colour frequencies on sunny and shaded trees, and at different seasons, did not suggest climatic selection. By manipulating the colour frequencies of subpopulations of small snails isolated on individual trees, it was shown that the disappearance of yellow and brown shells was frequency-dependent. This result is consistent with hypotheses of mimicry of background elements by the morphs and of apostatic selection by unknown predators. Only the latter can account for the persistence of the highly conspicuous pink morph at a low frequency.     

Microboring organisms in living stylasterid corals (Cnidaria,Hydrozoa)

Microboring or euendolithic microorganisms, which colonize and penetrate various carbonate substrates, are abundant in coral reef ecosystems and play a major role in reef carbonate dissolution. A few studies reported the presence of euendoliths in stylasterid coral skeletons but the biological identity, distribution and abundance of these microorganisms remain largely unknown. Observations of over 100 stylasterid colonies, collected in the Indo-Pacific area, revealed for the first time that the association between these corals and euendolith organisms appears to be quite common in shallow tropical waters. The most abundant euendolith was identified as a cryptic stage in the development of the rhodophyte Porphyra (Conchocelis stage). The euendoliths were observed in the skeletons of seven species of three genera (four Stylaster, two Distichopora and one Lepidotheca). The presence of euendoliths inside skeletons conferred a particular colour to the studied stylasterid corals. Distribution and abundance of microborings varied significantly among stylasterid species and among branches of a single colony and so did the colour of their skeletons. Colonization of skeletons and the associated colour distribution were almost uniform in some stylasterids, forming an upward gradually diminishing or sharply limited gradient. This study shows that patterns of euendolith colonization and growth in stylasterid skeletons may depend on the stage of the euendolith development as well as on their environmental requirements such as light exposure.     

New evidence for parallel evolution of colour patterns in Malagasy poison frogs (Mantella)

Malagasy poison frogs of the genus Mantella are diurnal and toxic amphibians of highly variable and largely aposematic coloration. Previous studies provided evidence for several instances of homoplastic colour evolution in this genus but were unable to sufficiently resolve relationships among major species groups or to clarify the phylogenetic position of several crucial taxa. Here, we provide cytochrome b data for 143 individuals of three species in the Mantella madagascariensis group, including four newly discovered populations. Three of these new populations are characterized by highly variable coloration and patterns but showed no conspicuous increase of haplotype diversity which would be expected under a scenario of secondary hybridization or admixture of chromatically uniform populations. Several populations of these variable forms and of M. crocea were geographically interspersed between the distribution areas of Mantella aurantiaca and Mantella milotympanum. This provides further support for the hypothesis that the largely similar uniformly orange colour of the last two species evolved in parallel. Phylogenies based on over 2000 bp of two nuclear genes (Rag-1 and Rag-2) identified reliably a clade of the Mantella betsileo and Mantella laevigata groups as sister lineage to the M. madagascariensis group, but did not support species within the latter group as monophyletic. The evolutionary history of these frogs might have been characterized by fast and recurrent evolution of colour patterns, possibly triggered by strong selection pressures and mimicry effects, being too complex to be represented by simple bifurcating models of phylogenetic reconstruction.     

Ultrastructure of Spermiogenesis in Hyla japonica (Anura,Amphibia)

Spermiogenesis in Hyla japonica was examined using transmission electron microscopy. Features which have not been reported previously during spermiogenesis of anurans include: (1) the neck of pericentriolar material is well developed, (2) the perforatorium contains many microtubules, (3) the tail is composed of axoneme and axial rod, but has no undulating membrane. Such a structure has not been described in amphibians, although it occurs in fish and mammals, and (4) the modified microtubules have one to two long projections. So far they have not been observed in any species except Gerris and Aphyosemion. With the exception of the above characteristics, the spermatozoa of Hyla japonica are remarkably similar to those of Bufo sp.     

Recent social environment affects colour-assortative shoaling in juvenile angelfish (Pterophyllum scalare)

Theory predicts that fish should show colour-assortative shoaling in order to avoid the oddity effect whereby individuals that differ in some feature from the group majority appear to incur increased risk of predation. It has also been shown that early experience plays an important role in affecting social preferences in some fish species. In this study, the importance of colour phenotype in promoting assortative shoaling and the role played by the recent social environment on its expression were investigated in juvenile angelfish, Pterophyllum scalare. Individuals of the uniformly black and golden colour morphs were housed in a group with conspecifics of like and unlike body colour to themselves, as well as in mixed-colour groups for 4 weeks. Subsequently, they were subjected to a binary choice to shoal with a group of conspecifics composed of unfamiliar fish of either a like or unlike colour phenotype to themselves. The response of the individuals to the colour attributes of the shoals was related to their recent social environment. Fish in like- and mixed-colour previous treatments showed a preferential association with like colour conspecifics. In contrast, the shoaling behaviour exhibited by fish previously maintained with a group of unlike-coloured conspecifics (cross-housed treatment) indicated no significant preference for any of the shoals. The results suggest that angelfish use body colouration as an intraspecific shoaling cue and that learning, in the form of recent familiarisation with a specific colour phenotype of conspecifics, can affect colour-assortative shoaling preferences in this species. This learning component of the choice need not be restricted to early developmental stages.     

Phylogenetic relationships and phylogeography of the Killifish species of the subgenus Chromaphyosemion (Radda, 1971) in West Africa, inferred from mitochondrial DNA sequences

We have analyzed the phylogenetic relationships of 160 specimens from 88 samples representing all defined species of the African Aplocheiloid subgenus Chromaphyosemion in order to examine the monophyly of this group, the species interrelationships, and to reveal trends in chromosomal evolution and formulate hypotheses about their evolutionary history. The data set comprised 1153 total nucleotides from the mitochondrial 12S rRNA, cytochrome oxidase I, and D-loop. The molecular-based topologies were analyzed by maximum parsimony, maximum likelihood, distance method and Bayesian inference support the monophyly of the subgenus Chromaphyosemion. All populations with ambiguous taxonomic status were assigned to an already described species except A. sp. Rio Muni which corresponds to a still undescribed species. Aphyosemion alpha and A. lugens were in basal position in the different trees that indicate a possible origin of the subgenus Chromaphyosemion in the South Cameroon-North Gabon region. Furthermore, the South Cameroon region (between 2 degrees and 3 degrees of North latitude) that accommodates half of the Chromaphyosemion species is considered to have been a refuge zone during the late quaternary dry events that Africa experienced. Phylogenetic relationships among the subgenus also revealed that chromosomal evolution is complex and should be studied at the intraspecific level.     

Colour morph related performance in the meadow grasshopper Chorthippus parallelus (Orthoptera,Acrididae)

Abstract 1. Polymorphism has been described for a number of herbivorous insects, but little is known about whether differences in body colour cause fitness differences. In Chorthippus parallelus, three main colour morphs occur, namely brown, green, and dorsally striped. 2. The present study examined colour morph abundances and morph‐related differences in body size, oviposition rate, and offspring numbers in females of C. parallelus collected in 15 montane grasslands. The study also examined the effect of plant species richness, composition, community productivity, and solar radiation on colour morph frequency and fitness. 3. The relative frequencies of the three colour morphs was 31.7% (brown), 33.1% (green), and 35.2% (dorsally striped), but the morphs were not evenly distributed across the 15 sites. 4. There was no effect of the habitat variables on the distribution of the green and the striped morph in the study sites, however 80% of the variation in the abundances of the brown morph was explained by plant species richness and composition. 5. Grasshopper size was equal among the morphs. Brown females laid significantly more egg pods than the green and dorsally striped morphs. There were no significant differences in offspring numbers among the colour morphs. 6. Body colour in C. parallelus seems to be a fitness‐relevant trait, raising the question of the evolutionary maintenance of polymorphism.     

Molecular phylogeny and diversification of freshwater shrimps (Decapoda, Atyidae, Caridina) from ancient Lake Poso (Sulawesi, Indonesia)--the importance of being colourful

Ancient Lake Poso on the Indonesian island Sulawesi hosts a highly diverse endemic fauna, including a small species flock of atyid Caridina shrimps, which are characterized by conspicuous colour patterns. We used a mtDNA based molecular phylogeny to test the assumption of a monophyletic origin and intralacustrine radiation of the species flock and to assess the species specificity of some colour morphs. Our data reveal a rapid radiation of Caridina in the entire Poso drainage system, but provide no strong evidence for a monophyletic radiation of the lake species. Nevertheless each lacustrine species shows a varying degree of substrate or trophic specialization, usually considered a hallmark of adaptive radiation. Two distinct colour forms previously attributed to a single species, C. ensifera, lack distinguishing qualitative morphological characters, but are shown to be two different species. In contrast, morphologically rather distinct lake species lacking specific colour patterns may be hybridizing with riverine taxa. These results suggest that colour may play a similar role in species recognition and possibly speciation in ancient lake Caridina as hypothesized, e.g. for some African cichlids.     

Colour polymorphism in the coconut crab (<Emphasis Type="Italic">Birgus latro</Emphasis>)

Coconut crabs (Birgus latro) are strikingly variable in coloration, but the significance of this colour diversity has never been investigated. We studied coloration, morphology, behaviour and background matching of adult coconut crabs, the world’s largest terrestrial invertebrate, at the western edge of its distribution on Pemba Island, Tanzania. Adults are evidently polymorphic; they come in red and blue types (3:1 ratio on Pemba). The best predictor of colour morph was ventral hue, which, using a discriminant function analysis, correctly classified 96% of the crabs assigned into a predefined colour group. In contrast, principal component analyses suggested a degree of overlapping colour variation. We found no evidence that coloration was sex or size-linked. Males were larger than females and the Pemba adult population appeared male-biased (3:1). We also report that red adults may match the background better than do blue adults on land, whereas blue match better near shore than do red. We postulate that although colour diversity in coconut crabs may be genetically determined, potentially through a crustacyanin gene polymorphism influencing the stability of integument pigmentation, its maintenance may involve several ecological drivers.