Left Forewing Research Articles

Morphometric study of the exuviae of Aeshna juncea (Linnaeus, 1758) (Odonata: Aeshnidae)

This study assessed various anatomical parameters of exuviae of three distinct populations of Aeshna juncea (Linnaeus, 1758) collected in Iran, the Netherlands and France. Fifty specimens (25 males, 25 females) from each country were analysed in detail. We measured 20 morphological traits for females and 19 traits for males. We found out that body length, left foreleg, left forewing sheath, left hindwing sheath, length of cercus, epiproct, epiproct spine, paraprocts and length of abdominal spines were larger in specimens originating from Iran compared to specimens collected in the studied areas of France and the Netherlands. In contrast, width of head and minimal width of prementum were larger in specimens from the Netherlands. According to our results, the measured morphological parameters indicated a greater similarity between the specimens found in France and the Netherlands compared to the specimens recorded in Iran. The presented data might be useful for future comparison of other populations of A. juncea throughout Eurasia.

Signatures of increasing environmental stress in bumblebee wings over the past century: Insights from museum specimens.

Determining when animal populations have experienced stress in the past is fundamental to understanding how risk factors drive contemporary and future species' responses to environmental change. For insects, quantifying stress and associating it with environmental factors has been challenging due to a paucity of time-series data and because detectable population-level responses can show varying lag effects. One solution is to leverage historic entomological specimens to detect morphological proxies of stress experienced at the time stressors emerged, allowing us to more accurately determine population responses. Here we studied specimens of four bumblebee species, an invaluable group of insect pollinators, from five museums collected across Britain over the 20th century. We calculated the degree of fluctuating asymmetry (FA; random deviations from bilateral symmetry) between the right and left forewings as a potential proxy of developmental stress. We: (a) investigated whether baseline FA levels vary between species, and how this compares between the first and second half of the century; (b) determined the extent of FA change over the century in the four bumblebee species, and whether this followed a linear or nonlinear trend; (c) tested which annual climatic conditions correlated with increased FA in bumblebees. Species differed in their baseline FA, with FA being higher in the two species that have recently expanded their ranges in Britain. Overall, FA significantly increased over the century but followed a nonlinear trend, with the increase starting c. 1925. We found relatively warm and wet years were associated with higher FA. Collectively our findings show that FA in bumblebees increased over the 20th century and under weather conditions that will likely increase in frequency with climate change. By plotting FA trends and quantifying the contribution of annual climate conditions on past populations, we provide an important step towards improving our understanding of how environmental factors could impact future populations of wild beneficial insects.

Differentiation between left and right wing stridulatory files in the field cricket Gryllus bimaculatus (Orthoptera: Gryllidae)

Male crickets produce acoustic signals by wing stridulation, attracting females for mating. A plectrum on the left forewing's (or tegmen) anal margin rapidly strikes along a serrated vein (stridulatory file, SF) on the opposite tegmen as they close, producing vibrations, ending in a tonal sound. The tooth strike rate of the plectrum across file teeth is equal to the sound frequency produced by the cricket (i.e., ∼5k teeth/s for ∼5 kHz in field crickets) and is specific to the forewing's resonant frequency. Sound is subsequently amplified using specialised wing cells. Anatomically, the forewings appear to mirror each other: both tegmina bear a SF and plectrum; however, most cricket species stridulate using right-over-left wing overlap making the stridulatory mechanism asymmetrical by default, rendering the left tegmen's SF unused. Therefore, we hypothesised structural differences between functional and unfunctional SFs. Three-dimensional mapping was used to accurately measure SF structures in Gryllus bimaculatus wings. We found that the left SF shows significantly greater variation in inter-tooth distance than the right, but less variation within the first sixty teeth (the functional part) than the right file. The left SF's slow evolutionary change over millions of years is discussed considering modern molecular phylogenies and fossil records.

A case of gynandromorphy in Ducetia japonica (Thunberg, 1815) (Orthoptera: Tettigoniidae: Phaneropterinae).

In this paper, we described an example of gynandromorphy in a katydid, Ducetia japonica. Its color is brown, while normal individuals are green. Its left maxilla is smaller, and left maxillary palpus is shorter. Left forewing as male is shorter than right one as female. Hindwing is also shorter in left. Cercus, epiproct and subgenital plate are left in male and right in female.

Fluctuating Asymmetry in Melipona scutellaris (L.) 1811 (Hymenoptera: Apidae) Associated to Stress due to Transportation of Colonies

Transportation to long distances and handling of colonies can affect development and survival conditions of bees. Our study investigated the stress intensity of individuals of Melipona scutellaris Latreille, 1811, due to transportation of colonies to long distances, within the natural range of the species. We used 746 bee workers. The right and left forewings were removed and measured using 15 landmarks in vein insertions. Individuals were divided into four groups: (1) workers collected at the origin site, (2) workers emerged at the place of destination in pupal stage during transportation, (3) workers emerged at the destination site in the 3rd instar of larval stage during transportation, and (4) workers collected after three months of colony establishment at the destination site. The Procrustes ANOVA showed significant results as well as the presence of Fluctuating Asymmetry (FA) in all treatments for the shape of wings (P<0.01). However, in the comparison of groups using the One-Way ANOVA, only workers that emerged at the destination site in the 3rd instar of larval stage during transportation (Group 3) significantly differentiated (P<0.05) from the others, with a higher FA index. The larval stage underwent more stress due to colony transportation. Beekeepers should take good care of colonies during transportation in order to minimize damages to workers to prevent quality loss of services and products offered by bees.

An appraisal of subspecific classification of Apis mellifera L. in parts of West and Central Africa through landmark-based geometric morphometric analysis of forewings

To appraise the subspecific classification of Apis mellifera L. in West and Central Africa, 1663 workers from 175 colonies from 44 localities, were sampled throughout Nigeria and parts of Niger, Cameroon and Chad. The samples were analysed with reference subspecies (A. m. adansonii (N = 12), A. m. jemenitica (N = 14) and A. m. scutellata (N = 12)), using geometric morphometric analysis, based on 19 landmarks on the left forewings of workers. The analysis allowed separating size and shape of the wing. Hierarchical cluster analysis followed by stepwise discriminant analysis (DA) grouped the colonies into two morphoclusters with a cross-validation classification rate of 96.6%. ANOVA revealed a significant difference (p < 0.0005) between the unknown colonies and either of A. m. jemenitica and A. m. scutellata but an insignificant difference (p > 0.05) between them and A. m. adansonii in respect of size. MANOVA revealed a significant difference (p < 0.0005) between the unknown colonies and each of the reference subspecies regarding shape or form (shape + size). All the colonies formed one cluster in a PCA of shape and form, respectively. Based on shape, DA assigned 46.02% and 2.84% of the unknown colonies to A. m. scutellata and A. m. adansonii, respectively, with a posterior probability of ≥95%. However, when shape and size were combined, DA assigned 28.40%, 21.02% and 10.23% of the unknown colonies to A. m. adansonii, A. m. scutellata and A. m. jemenitica, respectively, with a posterior probability of ≥95%. Thus, though this classification is not definitive, it suggests that the unknown colonies are morphologically closer to adansonii and scutellata than jemenitica. However, in order to avoid further confusion in the nomenclature of the honey bees of this region, it is recommended that A. m. adansonii could be retained as their sole subspecific name, pending further studies.

Wing asymmetry of a butterfly community: is altitude a source of stress?

We present a novel analysis of fluctuating asymmetry (FA) for butterfly wings at the community-level, along an altitudinal gradient. FA is an important biomonitoring tool that detects deviations of perfect symmetry in bilateral characters, assuming that genetic and/or environmental factors can be a source of stress. This study evaluated the effects of increased altitude on the symmetry of butterfly wings, testing the hypothesis that FA should increase with increased elevation in a tropical mountain. Butterflies were sampled along an altitudinal gradient of 800 to 1.400 m and forewings were detached, scanned and evaluated for symmetry. Length, width and area of the right and left forewings were measured as surrogates for FA and then combined into an index taking into account the variability of wing sizes of the whole butterfly community. We observed true patterns of FA in the length, width and area of the wings, and wing FA area increased with increased altitude. This study pioneered the analysis of FA for a community of butterflies and FA was efficient to detect developmental instability indicated by imperfections in butterfly wings.

Complex wing motion during stridulation in the katydid Nastonotus foreli (Orthoptera: Tettigoniidae: Pseudophyllinae)

Male Katydids (Orthoptera: Tettigoniidae) rub together their specialised forewings to produce sound, a process known as stridulation. During wing closure, a lobe on the anal margin of the right forewing (a scraper), engages with a tooth-covered file on the left forewing. The movement of the scraper across the file produces vibrations which are amplified by a large wing cell adjacent to the scraper, the mirror. Katydids are known to stridulate with either sustained or interrupted sweeps of the file, generating resonant pure-tone (narrowband frequency) or non-resonant (broadband frequency) calls. However, some species can conserve some purity in their calls despite incorporating discrete pulses and silent intervals. This mechanism is exhibited by many Pseudophyllinae, such as Nastonotus spp., Cocconotus spp., Triencentrus spp. and Eubliastes spp. This study aims to measure and quantify the mechanics of wing stridulation in Nastonotus foreli, a Neotropical katydid that can produce, relatively narrowband calls at ≈20 kHz. It was predicted that this species will use a stridulatory mechanism involving elastic energy whereby the scraper bends and flicks along the file in periodic bursts. The calling behaviour and wing mechanics of seven males were studied using a combination of technologies (e.g. micro-scanning laser Doppler vibrometry, advanced microscopy, ultrasound-sensitive equipment and optical motion detectors) to quantify wing mechanics and structure. Analysis of recordings revealed no clear relationship between wing velocity and carrier frequency, and a pronounced distinction between wing velocity and scraper velocity during wing closure, suggesting that the scraper experiences considerable deformation. This is characteristic of the elastic scraper mechanism of stridulation. Curiously, N. foreli might have evolved to employ elastic energy to double the duration of the call, despite possessing muscles that can reach velocities high enough to produce the same frequency without the help of elastic energy.

A new genus and species of Stenurothripidae (Insecta: Thysanoptera: Terebrantia) from mid-Cretaceous Myanmar amber

A new genus and species of thrips, Cenomanithrips primus gen et sp. nov., is described and assigned to the extant family Stenurothripidae of Thysanoptera. The new taxon is established primarily based on the following characters: pronotum with lateral, posteromarginal and posteroangular setae; forewing slender, narrow at apex, surface with microtrichia, two longitudinal veins present, only one cross-vein between the two longitudinal veins, with one seta on posterior vein basal to this cross-vein, anterior vein without setae, right forewing posterior vein with three setae, left forewing posterior vein with only one seta; hind wing with one longitudinal vein, fore tarsus 2-segmented, without a hamus and the terminal abdominal segment is not tube-like. The new amber thrips is the first fossil record of Stenurothripidae in Myanmar (Burmese) amber hitherto, dating to the mid-Cretaceous. Other fossil records of Stenurothripidae are in the Lower Cretaceous Spanish and Lebanese amber, in the Eocene Baltic, Bitterfeld and Rovno amber, and in the Miocene Bitterfeld amber. This new finding not only broadens the distribution and diversity of fossil Stenurothripidae, but also provides important morphological characters to enhance our understanding of the early evolutionary development of the Stenurothripidae.

A large cockroach from the mesosaur-bearing Konservat-Lagerstätte (Mangrullo Formation), Late Paleozoic of Uruguay.

Barona arcuata, n.gen et n.sp., a left forewing of a relatively large cockroach of the Order Blattaria, is described from mesosaur-bearing lagoonal shales of the Mangrullo Formation (north-eastern Uruguay). While most of the insect remains recovered from the Mangrullo Formation come from sandy limestones, associated to scarce isolated mesosaur bones and pygocephalomorph crustaceans, the cockroach wing here described was found in the overlaying green to brownish, gray and dark black shales associated to intercalated bentonites and evaporitic gypsum crystals. Barona arcuata shares some features with typical Late Carboniferous taxa such as its general venation pattern and outline of the wing, four main and powerful veins arising close together from near the base of the wing, Sc simple forked, pectinate, reaching the costal border through a long fork, R and M bifurcating and terminating in the wing margin above and below the apex respectively, short and narrow CuA, and the presence of a broad interspace between CuP and AA. Cross venation seems to be absent or it was not preserved. Some characters might relate Barona arcuata to the Late Carboniferous-Early Permian Neothroblattinidae such as the presence of sigmoidal veins in the anal area, a condition not found in any of the remaining representatives of the Palaeozoic Blattaria. Intriguingly, the Uruguayan blattarian also presents a strong similarity with Qilianiblatta namurensis Zhang, Schneider & Hong, 2012 from the Westphalian of China, clearly a smaller taxon that is also difficult to relate to any of the preexistent families. The apparent plesiomorphic venation pattern of the new species which is reminiscent of that present in the oldest known blattarians, is in agreement with a Permo-Carboniferous (Gzhelian-Asselian) age for the Mangrullo Formation also supported by the presence of a macrofloral assemblage dominated by arborescent lepidondendrids and other lycopsids and the pygocephalid-like morphology of the pygocephalomorph crustaceans from the same levels.

Describing Modularity in the Forewings of the Mango Leafhopper (Idioscopus clypealis)

The effects of environmental factors on genetic modules is important in understanding the development of organisms. This study was conducted to determine the developmental modules in the forewings of the mango leafhopper ( Idioscopusclypealis ) and establish if variation exists between populations attacking different hosts and between sexes. A total of 199 landmarks points were used to outline the margins and wing venation of the leafhopper. Models were constructed to hypothesize modularity in the wings. The ɣ* (Gamma*) test for Goodness of fit (GoF) was used to assess the best fit model. Results showed that the forewings of I. clypealis is partitioned into 5 developmental modules bounded by the major veins in all populations except for the left forewing of the female leafhopper in Paho variety (ɣ*= -0.25572, P=1). The results suggest that wing development is conserved but may be affected by host.

A new xyelotomid (Hymenoptera) from the Middle Jurassic of China displaying enigmatic venational asymmetry.

BackgroundPterygota insects typically have symmetric veins in left and right wings. For studying taxonomy and phylogeny of fossil insects, venational patterns are commonly used as diagnostic characters, in conjunction with preserved body characters. Some examples of asymmetrical venation are known among extant insects, but only a few fossil insects with asymmetric wings have been reported, among which a previously described xyelotomid of Hymenoptera, Xyelocerus diaphanous, displays an unusual, small cell of vein Rs in the left forewing, but not in the right.ResultsHerein we report a new sawfly of the family Xyelotomidae, Aethotoma aninomorpha gen. et sp. nov., from the late Middle Jurassic of China having a simple Sc in the forewing and Sc with two branches in the hind wing. In additional, the new specimen exhibits an enigmatic venational asymmetry. In the right forewing, crossvein 2r-rs of forms a loop, then forks into 2 long branches reaching Rs, while 2r-rs of the left forewing forks into 2 short branches reaching Rs, in contrast to a linear 2r-rs in typical fossil and extant sawflies.ConclusionSuch rare asymmetrical venation found from fossil sawflies provides a glance at early occurrences of venational variability and instability, or possibly aberrational development, for insects in the late Middle Jurassic.

A Single-Wing Removal Method to Assess Correspondence Between Gene Expression and Phenotype in Butterflies: The Case of Distal-less.

It is often desirable but difficult to retrieve information on the mature phenotype of an immature tissue sample that has been subjected to gene expression analysis. This problem cannot be ignored when individual variation within a species is large. To circumvent this problem in the butterfly wing system, we developed a new surgical method for removing a single forewing from a pupa using Junonia orithya; the operated pupa was left to develop to an adult without eclosion. The removed right forewing was subjected to gene expression analysis, whereas the non-removed left forewing was examined for color patterns. As a test case, we focused on Distal-less (Dll), which likely plays an active role in inducing elemental patterns, including eyespots. The Dll expression level in forewings was paired with eyespot size data from the same individual. One third of the operated pupae survived and developed wing color patterns. Dll expression levels were significantly higher in males than in females, although male eyespots were smaller in size than female eyespots. Eyespot size data showed weak but significant correlations with the Dll expression level in females. These results demonstrate that a single-wing removal method was successfully applied to the butterfly wing system and suggest the weak and non-exclusive contribution of Dll to eyespot size determination in this butterfly. Our novel methodology for establishing correspondence between gene expression and phenotype can be applied to other candidate genes for color pattern development in butterflies. Conceptually similar methods may also be applicable in other developmental systems.

Use of geometric morphometrics to differentiate selected lines of Carniolan honeybees (Apis mellifera carnica) in Serbia and Montenegro

In a selection of honeybees from autochthonous ecotypes, different lines must be identified. Honeybee lineages are usually distinguished by classical morphometrics and molecular markers, but these approaches are both costly and time-consuming to implement. Recognition of the purity of races is very important for regional and country regulations to allow a sustainable conservation of the huge variety of local honeybees. A geometric morphometric approach has been frequently used. In this work, honeybee samples were collected from stationary apiaries (belonging to the centers for honeybee queen selection) from two different Serbian areas: Vrsac (northeastern Serbia, mostly flatland) and Vranje (southern Serbia, mostly mountainous), and two different Montenegrin areas: Bijelo Polje (northern Montenegro, mountainous region) and Sutomore (southern Montenegro, coastal region). Each sample consisted of 150 honeybee workers, collected from 10 hives (15 specimens each). On the honeybee left forewings, a total of 19 vein intersections were used to determine the differences among the honeybees using MorphoJ 1.4a software. Canonical variate analysis (CVA) slightly separated the honeybee lines into one overlapping cloud of specimens at the individual level. The first canonical variable (60.57% of the total variability) discriminated mainly between Bijelo Polje and Sutomore honeybee lines. Therefore, on the colony level, CVA separated all four groups of breeding honeybee lines. The results show that geometric morphometrics are reliable in the discrimination of honeybee lines within subspecies only at the colony level.

A new species ofPseudotettigoniaZeuner (Orthoptera:Tettigoniidae) with an intact stridulatory field and reexamination of the subfamilyPseudotettigoniinae

AbstractPseudotettigonia leonasp.n.is described from a single left forewing collected from theMiddleEoceneKishenehnFormation in northwesternMontana, U.S.A.P. leonais the second of only two fossil macropterousTettigoniidae that preserve an intact stridulatory apparatus. The subfamilyPseudotettigoniinae is reexamined. The specific epithetbriceiis assigned to thelateMiocene fossil tettigoniidTettigonia briceisp.n., originally described as the extantTettigonia viridissima.This published work has been registered in ZooBank,http://zoobank.org/urn:lsid:zoobank.org:pub:E69E83CE‐9046‐4BBD‐AA11‐E0AD0C382700.

Grylloptera - a unique origin of the stridulatory fi le in katydids, crickets, and their kin (Archaeorthoptera)

Topographic homology conjectures (= THCs) of male forewing venation in extant ensiferan orthopterans (crickets, katydids, and their kin) and their close stem-relatives are re-evaluated, in order to test competing hypotheses on the origin(s) of the fi le (a row of teeth located on the ventral side of the forewing and used in stridulation). A new set of THCs (= STHC) is proposed, based on morphological data on the species †zeuneri Sharov, 1968, obscura Walker, 1869, monstrosa Uhler, 1864, †madygenicus Sharov, 1968: p. 181, grandidieri de Saussure, 1877: p. 287, bimaculatus de Geer, 1773, villosiceps Chopard, 1951, frontalis Walker, 1869, gryllotalpa Linnaeus, 1758, vicinus Scudder, 1869, and cantans Fuesslin, 1775. This STHC is compared to that proposed by Desutter-Grandcolas (2003) and is found to require a smaller amount of transformation to explain the observed morphologies. The favoured STHC implies that the stridulatory fi le is located along the same vein in all scrutinized taxa (viz. CuPb). Current phylogenetic hypotheses cannot rule out that the fi le was acquired once only. Furthermore, multiple losses explain the observed distribution more plausibly than multiple acquisitions of a complex structure. A new type of wing venation transformation is evidenced, referred to as tracheal un-capture. It involves a vein abandoning its usual course for another, and leaving a remnant of its previous course, in the form of a cross-vein-like structure (‘phantom vein’). The taxon Grylloptera is defined under cladotypic nomenclature, and is the lineage in which the character state ‘on ventral side, right and/or left forewings with a row of teeth (‘fi le’) located along CuPb’, as exhibited by viridissimus Linnaeus, 1758: p. 430 and campestris Linnaeus, 1758: p. 428, has been acquired. Type material is designated.

The reduviid genus Nagustoides Miller (Heteroptera: Reduviidae: Harpactorinae) found in China, with description of a new species

The genus Nagustoides Miller, 1954 is recorded for the first time from China. Nagustoides lii is described as new to science. A key to the species of genus is provided. The diagnostic characters of the genus Nagustoides are revised. The abnormal venation of left fore wing of a female is noted. The type specimens are preserved in the Entomological Museum of China Agricultural University, Beijing.

Output connections of a wind sensitive interneurone with motor neurones innervating flight steering muscles in the locust.

The output connections of a bilaterally symmetrical pair of wind-sensitive interneurones (called A4I1) were determined in a non-flying locust (Schistocerca gregaria). Direct inputs from sensory neurones of specific prosternal and head hairs initiate spikes in these interneurones in the prothoracic ganglion. The interneurone with its axon in the right connective makes direct, excitatory connections with the two mesothoracic motor neurones innervating the pleuroaxillary (pleuroalar, M85) muscle of the right forewing, but not with the comparable motor neurones of the left forewing. The connections can evoke motor spikes. The interneurones also exert a powerful, but indirect effect on the homologous metathoracic pleuroaxillary motor neurones (muscle 114), and a weaker, indirect effect on subalar motor neurones of the hindwings. No connections or effects were found with other flight motor neurones, or motor neurones innervating hindleg muscles, including common inhibitor 1 which also innervates the pleuroaxillary muscle. One thoracic interneurone with its cell body in the right half of the mesothoracic ganglion and with its axon projecting ipsilaterally to the metathoracic ganglion receives a direct input from the right A4I1 interneurone. These restricted output connections suggest a role for the A4I1 interneurones in flight steering.

Changes in Gypsy Moth (Lepidoptera: Lymantriidae) Fecundity and Male Wing Length Resulting from Defoliation

The influence of defoliation on gypsy moth fecundity and male moth wing length and the relationship between male moth wing length and egg mass density were investigated. Male pupae and egg masses were collected from plots located in the leading edge area of the gypsy moth infestation in Virginia and Maryland. Defoliation and egg mass density estimates were made in each plot. Male pupae were allowed to emerge, and the left forewings of 2,636 moths were measured to determine wing length. Fecundity was determined volumetrically for 767 egg masses. Gypsy moth fecundity and male wing length decreased substantially only when defoliation exceeded a threshold level of ≍40%. There was a minimal change in fecundity and male wing length due to increasing levels of defoliation above or below this threshold. Thus, the effect of defoliation on male wing length and fecundity is essentially binomial (i.e., male wing lengthy is either large or small and fecundity is either high or low). Wing length of male moths explained only ≍10% of the variation in egg mass density in the area where pupae were collected. The wing length of moths captured in pheromone traps used in conjunction with the number of moths captured may be useful for monitoring gypsy moth populations.

Body Size and the Functional Length of the Proboscis of Honey Bees

Three measurements on the left forewing, and head width, were used to predict functional proboscis length of honey bees (Apis mellifera ligustica). Functional length of the proboscis (FLP) is a measure of the depth that the proboscis can be extended to reach nectar in tubular flowers and is operationally the depth of a vertical capillary tube (inside diam = 1mm) emptied of sucrose solution. The morphometric characters were useful predictors of FLP, which may affect honey been foraging behavior.