Evolution of wing shape in hornets: why is the wing venation efficient for species identification?

Wing venation has long been used for insect identification. Lately, the characterization of venation shape using geometric morphometrics has further improved the potential of using the wing for insect identification. However, external factors inducing variation in wing shape could obscure specific differences, preventing accurate discrimination of species in heterogeneous samples. Here, we show that interspecific difference is the main source of wing shape variation within social wasps. We found that a naive clustering of wing shape data from taxonomically and geographically heterogeneous samples of workers returned groups congruent with species. We also confirmed that individuals can be reliably attributed to their genus, species and populations on the basis of their wing shape. Our results suggested that the shape variation reflects the evolutionary history with a potential influence of other factors such as body shape, climate and mimicry selective pressures. However, the high dimensionality of wing shape variation may have prevented absolute convergences between the different species. Wing venation shape is thus a taxonomically relevant marker combining the accuracy of quantitative characters with the specificity required for identification criteria. This marker may also highlight adaptive processes that could help understand the wing's influence on insect flight.     

Fluctuating asymmetry in the honey bee,Apis mellifera: effects of ploidy and hybridization

We present a new measure of morphological asymmetry that avoids most of the statistical problems inherent in character-by-character analysis of size or shape. The method is an application of Procrustes analysis, which computes best-fitting super-positions of configurations of landmarks to the left and right sides of a single specimen. The Procrustes method combines subtle deviations in all aspects of the landmark configuration into one net asymmetry score. Directional asymmetry is separated from fluctuating asymmetry in a simple partition of a net sum-of-squares, and geometrical details of either component can be inspected by traditional methods of multivariate statistical analysis of landmarks. We demonstrate this method in a comparison of wing venation asymmetry in male (haploid) and female (diploid) honey bees (Apis mellifera). In addition we investigate the effects of ploidy and inter-subspecies hybridization on asymmetry and wing venation abnormalities, using the subspecies A. m. mellifera, A. m. carnica, and the hybrid strain “Nigra”. Results suggest that while the haploid males showed a higher frequency of wing venation abnormalities and greater total asymmetry than the diploid females, most of the asymmetry difference between males and females was in the form of directional, not fluctuating, asymmetry. Hybrid females had a higher frequency of wing venation abnormalities than females of either subspecies, but there were no significant differences in the mean level of asymmetry among females of A. m. mellifera, A. m. carnica and hybrid Nigra. Hybrid males had higher absolute frequency of wing venation abnormalities and asymmetry than males of either subspecies. However the mean frequency of venation abnormalities did not differ significantly between Nigra and A. m. carnica males, and mean asymmetries were not significantly different between Nigra and A. m. mellifera males. We discuss the relationship which is assumed to exist between developmental stability and fluctuating asymmetry in light of our result.     

Phylogeny of the Sympetrinae (Odonata: Libellulidae): further evidence of the homoplasious nature of wing venation

Abstract.  Sympetrinae is the largest subfamily of the diverse dragonfly family Libellulidae. This subfamily, like most libellulid subfamilies, is defined currently by a few wing venation characters, none of which are synapomorphies for the taxon. In this study, we used DNA sequence data from the nuclear locus elongation factor-1α and the mitochondrial loci 16S and 12S rRNA, together with 38 wing venation characters, to test the monophyly of the Sympetrinae and several other libellulid subfamilies. No analysis recovered Sympetrinae as monophyletic, partly because of the position of Leucorrhinia (of the subfamily Leucorrhininae) as a strongly supported sister to Sympetrum (of Sympetrinae) in all analyses. The subfamilies Brachydiplactinae, Leucorrhininae, Trameinae and Trithemistinae were also found not to be monophyletic. Libellulinae was the only subfamily supported strongly as monophyletic. Consistency indices and retention indices of wing venation characters used to define various subfamilies were closer to zero than unity, showing that many of these characters were homoplasious, and therefore not useful for a classification scheme within Libellulidae.     

Morphological variation versus genetic divergence: a taxonomic implication for Mogannia species (Cicadidae: Cicadinae)

Species showing intraspecific morphological variation tend to be very difficult to identify using morphological characters. One such example is the cicada genus Mogannia where some species show considerable intraspecific variation mainly exhibited by wing pattern and body colouration. Thirty-one variants covering different putative species of Mogannia were recognized and illustrated in the present paper. Molecular data of mitochondrial COI and Cytb sequences were employed to test the level of variation and phylogeny of them. The existence of a ‘barcoding gap’ between intraspecific and interspecific genetic divergences and the reciprocally monophyletic clades indicate that all the closely related variants represent a single species, and that all these variants correspond to six species, respectively. However, the evolutionary relationships of intraspecific variants are not resolved possibly due to insufficient genetic variation among them. Our results indicated that some morphological characters, especially the wing pattern and body colouration, and even the number of apical processes of the aedeagus in a couple of related species, must be used with great caution in delimiting Mogannia species and their relatives. The factors responsible for intraspecific morphological variation and phylogeny of Mogannia spp. are preliminarily discussed.     

A New Method for Preparing Slide Mounts of Whole Bodies of Microlepidoptera

A new method is described for preparing slide mounts of whole bodies of microlepidoptera to facilitate comparative morphological studies. This method conserves traditional characters of wing pattern while revealing wing venation and other morphological structures of the denuded body. Examples of new characters revealed on slide mounts of whole bodies and photographed with a Confocal Laser Scanning Microscope are given for selected species of Gelechioidea. Also, the historical use of morphological characters for defining taxa of Lepidoptera is briefly reviewed.     

Miocene honey bees from the Randeck Maar of southwestern Germany (Hymenoptera, Apidae)

The Miocene Randeck Maar (southwestern Germany) is one of the only sites with abundant material of fossil honey bees. The fauna has been the focus of much scrutiny by early authors who recognized multiple species or subspecies within the fauna. The history of work on the Randeck Maar is briefly reviewed and these fossils placed into context with other Tertiary and living species of the genus Apis Linnaeus (Apinae: Apini). Previously unrecorded specimens from Randeck Maar were compared with earlier series in an attempt to evaluate the observed variation. A morphometric analysis of forewing venation angles across representative Recent and Tertiary species of Apis as well as various non-Apini controls was undertaken to evaluate the distribution of variation in fossil honey bees. The resulting dendrogram shows considerable variation concerning the wing venation of Miocene Apini, but intergradation of other morphological characters reveals no clear pattern of separate species. This suggests that a single, highly variable species was present in Europe during the Miocene. The pattern also supports the notion that the multiple species and subspecies proposed by earlier authors for the Randeck Maar honey bee fauna are not valid, and all are accordingly recognized as Apis armbrusteri Zeuner.     

Phylogeny,landmark analysis and the use of wing venation to study the evolution of social wasps (Hymenoptera: Vespidae: Vespinae)

Wing venation provides useful characters with which to classify extant and fossil insects. Recently, quantification of its shape using landmarks has increased the potential of wing venation to distinguish taxa. However, the use of wing landmarks in phylogenetic analyses remains largely unexplored. Here, we tested landmark analysis under parsimony (LAUP) to include wing shape data in a phylogenetic analysis of hornets and yellow jackets. Using 68 morphological characters, nine genes and wing landmarks, we produced the first total‐evidence phylogeny of Vespinae. We also tested the influence of LAUP parameters using simulated landmarks. Our data confirmed that optimization parameters, alignment method, landmark number and, under low optimization parameters, the initial orientation of aligned shapes can influence LAUP results. Furthermore, single landmark configurations never accurately reflected the topology used for data simulation, but results were significantly close when compared to random topologies. Thus, wing landmark configurations were unreliable phylogenetic characters when treated independently, but provided some useful insights when combined with other data. Our phylogeny corroborated the monophyly of most groups proposed on the basis of morphology and showed the fossil Palaeovespa is distantly related to extant genera. Unstable relationships among genera suggest that rapid radiations occurred in the early history of the Vespinae.     

Evolutionary relationships of wing venation and wing size and shape in Aphidiinae (Hymenoptera: Braconidae)

We explored evolutionary changes in wing venation and wing size and shape in Aphidiinae, one of the well-known groups of parasitic wasps from the family Braconidae. Forewings of 53 species from 12 genera were examined, for which a molecular phylogeny was constructed on the basis of the mitochondrial barcoding gene COI. By covering all types of wing venation within the subfamily Aphidiinae and by using landmark-based geometric morphometrics and phylogenetic comparative methods, we tested whether evolutionary changes in wing shape correlate to the changes in wing venation and if both changes relate to wing size. The relationship between wing morphology and host specificity has been also investigated. We found that six types of wing venation, with different degree of vein reduction, could be recognized. Wing venation type is largely genus specific, except in the case of maximal reduction of wing venation which could be found across examined Aphidiinae taxa. The reconstruction of evolutionary changes in wing venation indicates that evolutionary changes in wing shape are related to the changes in wing size, indicating that miniaturization play a role in evolution of wing morphology while host specialization does not affect the wing shape within the subfamily Aphidiinae.     

基于后翅特征的中国芫菁科(鞘翅目,拟步甲总科)族级阶元系统发育分析

通过对中国芫菁科5族11属19种(亚种)后翅翅脉、翅关节和翅基部综合特征的比较形态学研究,归纳了族级特征,并用Hennig 86(1.5)软件对其后翅综合特征进行支序分析得出它们之间初步的进化关系,即栉芫菁族Nemognathini+(齿角芫菁族Cerocomini+(豆芫菁族Epicautini+(绿芫菁族Lyttini+斑芫菁族Mylabrini)))。     

Variability of the quantitative and qualitative traits of Aedes dorsalis mosquitoes from larval cultures of varying densities

Larvae of Aedes dorsalis Mg. were maintained at the density of 0.05 and 0.5 spec./ml. It was noted that mosquitoes from overpopulated cultures grew smaller in size. The wings became shorter and more narrow by 4 to 6%. The wing reduction occurred on account of its distal elements (veins r3 and m2). Despite the decrease in the value of characters their variability decreased too, having increased only for wing width and vein mcu. In overpopulated cultures the wing length connection with veins r3 and m2 grew weaker in males while in females only such tendency was observed. Wing bilateral asymmetry was noted: left wing of females became wider and those of males wider and shorter. Analysis of variability of qualitative wing characters, which were singled out according to the venation pattern, has shown that of 9 studied characters only two depended on density (arrangement of corners of radial and medial vectors) and only in females. The role of such wing changes for swarming, active escaping from danger, direction and distance of flight of mosquitoes is discussed.     

EVOLUTION OF VARIATION AND VARIABILITY UNDER FLUCTUATING,STABILIZING, AND DISRUPTIVE SELECTION

How variation and variability (the capacity to vary) may respond to selection remain open questions. Indeed, effects of different selection regimes on variational properties, such as canalization and developmental stability are under debate. We analyzed the patterns of among‐ and within‐individual variation in two wing‐shape characters in populations of Drosophila melanogaster maintained under fluctuating, disruptive, and stabilizing selection for more than 20 generations. Patterns of variation in wing size, which was not a direct target of selection, were also analyzed. Disruptive selection dramatically increased phenotypic variation in the two shape characters, but left phenotypic variation in wing size unaltered. Fluctuating and stabilizing selection consistently decreased phenotypic variation in all traits. In contrast, within‐individual variation, measured by the level of fluctuating asymmetry, increased for all traits under all selection regimes. These results suggest that canalization and developmental stability are evolvable and presumably controlled by different underlying genetic mechanisms, but the evolutionary responses are not consistent with an adaptive response to selection on variation. Selection also affected patterns of directional asymmetry, although inconsistently across traits and treatments.     

Zoraptera wing structures: evidence for new genera and relationship with the blattoid orders (Insecta: Blattoneoptera)

Abstract. The order Zoraptera has traditionally been thought to contain only one family (Zorotypidae) and one genus ( Zorotypus Silvestri). An analysis of known zorapteran wings shows that the wing venation contains character sets indicative of the existence of seven genera: Zorotypus, Brazilozoros gen.n., Centrozoros gen.n., Floridazoros gen.n., Latinozoros gen.n., Meridozoros gen.n. and Usazoros gen.n. The wing venation of Meridozoros leleupi (Weidner) from the Galapagos Islands, Ecuador and Venezuela is described here for the first time.
The major wing structures show that Zoraptera belong to the blattoid lineage. Head and abdomen characters indicate that Zoraptera probably diverged from the Blattoneoptera stock early, almost certainly before the (Protelytroptera + Dermaptera) line, and much before the (Isoptera + (Blattodea + Mantodea)) line. A homologized wing vein system is proposed for the Isoptera.
The homologized wing vein system is based on the hypothesis that the Pterygota originated with the development of protowings, which then diverged through separate but characteristic adaptations for flapping flight. Therefore the basic wing venation pattern is monophyletic, but the changes in wing musculature, articulation and basic braces between main veins are different in the major (super-ordinal) pterygote lineages (Pleconeoptera, Orthoneoptera, Blattoneoptera, Hemineoptera and Endoneoptera). Thus, these characters provide an extremely useful, almost untapped, source of data for higher-level systematics. Both higher-level and lower-level wing characters have been applied here to the phylogeny of Zoraptera and are discussed.     

中国锯天牛族后翅翅脉研究(鞘翅目,天牛科,锯天牛亚科,锯天牛族)(英文)

对中国锯天牛族的后翅基部关节和后翅翅脉特征进行了研究,发现利用Kukalová-Peck和Lawrence (2004)的后翅命名系统能够很好地对中国锯天牛族后翅翅脉进行命名。但是在中国锯天牛族中,后中脉( MP)和前肘脉(CuA)在后缘并不合并;当前臀脉( AA3)和前肘脉(CuA3 +4)与后肘脉(CuP)相遇时,前臀脉(AA3)消失,前肘脉(CuA3 +4)和后肘脉(CuP)合并,因此楔室(W)仅由肘脉(Cu)的分支脉围成。尽管基部翅关节在研究的各属和各种之间没有表现出差异,但是后翅翅脉在土天牛属Dorysthenes和锯天牛属Prionus不同种类之间差异明显,这些特征包括径室的长宽比例和各边的长度关系、r3存在与否及其长度、后径脉的长度、楔室的长宽比例、以及后中脉(MP3 +4)和前肘脉(CuA3 +4)端部是否分叉等。因此,后翅翅脉特征在土天牛属Dorysthenes和锯天牛属Prionus分种时可能具有分类学意义。     

Evolution and Function of Leaf Venation Architecture: A Review

The leaves of extant terrestrial plants show highly diverseand elaborate patterns of leaf venation. One fundamental featureof many leaf venation patterns, especially in the case of angiospermleaves, is the presence of anastomoses. Anastomosing veins distinguisha network topologically from a simple dendritic (tree-like)pattern which represents the primitive venation architecture.The high degree of interspecific variation of entire venationpatterns as well as phenotypic plasticity of some venation properties,such as venation density, indicate the high selective pressureacting on this branching system. Few investigations deal withfunctional properties of the leaf venation system. The interrelationshipsbetween topological or geometric properties of the various leafvenation patterns and functional aspects are far from beingwell understood. In this review we summarize current knowledgeof interrelationships between the form and function of leafvenation and the evolution of leaf venation patterns. Sincethe functional aspects of architectural features of differentleaf venation patterns are considered, the review also refersto the topic of individual and intraspecific variation. Onebasic function of leaf venation is represented by its contributionto the mechanical behaviour of a leaf. Venation geometry anddensity influences mechanical stability and may affect, forexample, susceptibility to herbivory. Transport of water andcarbohydrates is the other basic function of this system andthe transport properties are also influenced by the venationarchitecture. These various functional aspects can be interpretedin an ecophysiological context. Copyright 2001 Annals of BotanyCompany Review, leaves, leaf venation, evolution, network, transport, flow, mechanical stabilization     

Points of View Exploring the boundaries of environmental stress and fluctuating asymmetry: is Eumantispa (Neuroptera: Mantispidae) exceptional?

Eumantispa spp. usually show markedly asymmetrical wing venation, and this character is used in defining the genus. This is illustrated and discussed in relation to fluctuating asymmetry, which is used as a measure of environmental stress. © Rapid Science Ltd. 1998     

Inter- and intraspecific genetic and morphological variation in a sibling pair of carabid species

Background

Pogonus littoralis and Pogonus chalceus are very close related species with quite different ecological preferences within salt marshes. We study the evolutionary processes in and between these presumably young species. Therefore, we compare the variation in ecologically relevant characters and the genetic variation within one of the species (intraspecific differentiation) with the variation of the two types of characters between the two species (interspecific variation). Data are compared between two independent sets of populations, one set at a small geographical scale (the ecologically diverse Guérande area in France) and the other set at a Atlantic-Mediterranean scale.

Results

Body and relative wing size and IDH1 allozyme data show that the intraspecific variation in P. chalceus is high and in the same range as the interspecific variation (P. chalceus versus P. littoralis). Based on neutral markers (other allozymes and mitochondrial DNA) on the other hand, the intraspecific variation in P. chalceus is much lower in comparison to the interspecific variation.

Conclusion

The different ecotypes in the highly polytypic species P. chalceus are as highly differentiated in ecological characters as true species, but are not recognised as such by screening neutral DNA polymorphisms. This can be interpreted as a case of ongoing speciation driven by natural selection adapting each ecotype to its respective ecological niche. The same ecological process can be recognised in the differentiation between the two sister species, where en plus reproductive isolation between the two gene pools occurred, allowing independent drift and mutation accumulation in neutral genetic characters.     

DEVELOPMENT,FUNCTION, AND THE QUANTITATIVE GENETICS OF WING MELANIN PATTERN IN PIERIS BUTTERFLIES

Do genetic correlations among phenotypic characters reflect developmental organization or functional coadaptation of the characters? We test these hypotheses for the wing melanin pattern of Pieris occidentalis butterflies, by comparing estimated genetic correlations among wing melanin characters with a priori predictions of the developmental organization and the functional (thermoregulatory) organization of melanin pattern. There were significant broad-sense heritabilities and significant genetic correlations for most melanin characters. Matrix correlation tests revealed significant agreement between the observed genetic correlations and both developmental and functional predictions in most cases; this occurred even when the overlap between developmental and functional predictions was eliminated. These results suggest that both developmental organization and functional coadaptation among melanin characters influence the genetic correlation structure of melanin pattern in this species. These results have two important implications for the evolution of melanin pattern in P. occidentalis and other butterflies: 1) most phenotypic variation in pattern may reflect variation among, rather than within, sets of developmentally homologous wing melanin characters; and 2) in a changing selective environment, genetic correlations may retard the disruption of functionally coupled melanin characters, thus affecting the evolutionary response to selection.