Maxillary Palps Research Articles

A Synthetic Blend of Fruit and Live Yeast Odours Shows Promise for Trapping Mated Female Queensland Fruit Fly, Bactrocera tryoni, in the Field.

Tephritid fruit flies are major horticultural pests of fruit and vegetable crops. Developing an odour lure that can attract mated female flies under field conditions has presented a major challenge to chemical ecologists around the globe. We have designed a new lure to attract female Queensland fruit fly, Bactrocera tryoni, based on the knowledge that this pest tephritid is attracted not only to odours from ripening fruits, but also to odours of symbiotic (gut-associated) yeasts on which the larvae feed. Initial field trials screened four volatile mixtures, each containing a base mix of three, short-chain "fruit ripening" esters and differing in the addition of long-chain "fruity" esters and / or alcohols produced by live yeasts. Results demonstrated that the lure formulated from short-chain esters and live yeast alcohols attracted the most female flies, with significantly higher catches than an odourless control trap, and a protein-baited trap. As electrophysiological studies exploring peripheral responses in tephritids to alcohols associated with fermentation have not been extensively investigated, we conducted this work on both the antennae and maxillary palps, and discovered that three yeast alcohols were detected by both sensory organs. Performance trials conducted in pome fruit and stone fruit orchards evaluated the six-component blend of short-chain ester and live yeast alcohol lure against a commercially available synthetic fruit-odour lure and a protein-based lure. In the apple orchard, the new lure caught significantly more female flies, and in particular mated females, compared to the commercially available lures. In the stone fruit orchard, while the new lure again caught the most mated female flies compared to the other lures, differences were not significant. The visual stimulus (trap design) used had a significant effect on capture, with a Ladd trap (red sphere on a yellow panel) being considerably more effective than the other traps. We discuss the implications of this study, including why the degree of effectiveness of the new lure might have differed among the test orchards (citrus, apple, stonefruit), and why yeast odours might increase attractiveness to "ripening fruit" volatile blends under field conditions.

Transitional morphology and Afrotropical affinity of a bythinoplectine rove beetle from the early Eocene of India (Coleoptera: Staphylinidae: Pselaphinae)

Recently discovered Ypresian-age amber from Cambay, India, reveals an ancient arthropod assemblage on the Indian subcontinent during its collision with Asia. Despite the tectonic history of India, limited connections have been found between the Cambay palaeofauna and present-day Madagascan and mainland African faunas. Here, I describe a new fossil pselaphine rove beetle (Staphylinidae: Pselaphinae) recovered from the Cambay deposit that shows closest apparent phylogenetic affinity to modern Afrotropical genera. Yprezethinus grimaldii gen. et sp. nov. is placed in Bythinoplectini, subtribe Bythinoplectina. Based on antennal and maxillary palp morphology, Yprezethinus is a putative transitional stem lineage of the Zethinus-group of genera—an extant clade distributed across equatorial African rainforests. Although Yprezethinus shares with this clade the derived feature of ovoid antennal clubs formed by tight appression of the apical two segments, it differs from its putative extant relatives in its possession of the plesiomorphic complement of 11 antennomeres, without any fusions of segments. The fossil taxon signifies a biotic link between early Eocene India and continental Africa, and marks the Cenozoic emergence of a tropical leaf litter arthropod fauna approaching that of contemporary, ant-dominated rainforests.

Palleptoceridae fam. nov., an extinct leptoceroid family in mid-Cretaceous Burmese amber (Insecta, Trichoptera)

The family Palleptoceridae fam. nov. is proposed as a new extinct family of the superfamily Leptoceroidea. It is characterized by the absence of ocelli, the presence of five-segmented maxillary palps in both sexes, antennae longer than the forewings, and the tibial spur in the form of 2/4/4. The extinct Palleptoceridae is closely related to the leptoceroid family Leptoceridae, but the formula for the adult tibial spur is reduced from 2/4/4 to 2/2/4 (Morse, 1981). The Palleptocerus grimaldii sp. nov. from the mid-Cretaceous Burmese amber is furthermore characterized by the sexual dimorphic wing venation. In the forewings, the apical forks I and V are present in the male and forks I, III, and V in the female; in the hind wings of both sexes, exclusively the apical fork V is present. The Leptoceroidea originated and evolved in Gondwana. Palleptocerus grimaldii sp. nov. is interpreted as a relict species of the Gondwanan Leptoceroidea in Burmese amber.

The larval morphology of a new mid-Cretaceous stonefly and its systematic position in Plecoptera

The larval stage is an essential part of the life history of stoneflies and can provide substantial biological and evolutionary information. However, well-preserved fossils of larvae are sparse. Herein, the larval morphology of a new extinct stonefly, Kachinoperla zwickigen. et sp. nov., is described based on its exuvia in mid-Cretaceous Kachin amber from northern Myanmar (98.79±0.62 Ma). The new stonefly also represents a new family, Kachinoperlidaefam. nov. according to its unique characters. Kachinoperlidae can be distinguished from other stonefly families by the following larval characters: predaceous mouthparts, subequal glossae and paraglossae, subequal maxillary and labial palps, reduced apical maxillary palpomere, trapezoidal pronotum, banded and semicircular wing pads, invisible notal contour, absent thoracic gills, shortest first two tarsomeres, and strongly projected abdominal tergum 10. The morphological comparison and phylogenetic analysis suggested the new family as a basal lineage within Systellognatha. Evolutionary implications implied by the larval characters are also discussed.

No functional contribution of the gustatory receptor, Gr64b, co-expressed in olfactory sensory neurons of Drosophila melanogaster

Chemosensation is essential for the survival of insects. Activities like searching for food, mating, and oviposition in the fruit fly, Drosophila melanogaster are to a great extent governed by chemical cues detected via olfaction and gustation. This chemical information is conveyed to higher brain centers via populations of diverse olfactory sensory neurons (OSNs) and gustatory sensory neurons (GSNs) expressing olfactory receptors (ORs) and gustatory receptors (GRs), respectively. ORs are exclusively expressed in the antenna and in the maxillary palps, while GRs are widely expressed in the labellum, tarsi, genitalia etc. Interestingly, 14 GRs were previously reported to be expressed in the antenna of D. melanogaster. However, the spatial expression pattern for all GRs and their functional role are still unclear. Recent data challenge the dogma that single OSNs express a single OR. In the present study, we studied the expression of 12 previously reported GRs among sensory structures on the fly antenna using the Gal4-UAS binary expression system. We observed antennal expression of nine out of the 12 reported. Out of these nine, consistent expression was only apparent for Gr64b, and we reconfirmed its presence in OSNs innervating three glomeruli in the antennal lobe. These glomeruli are known to be innervated by ab5A, ab5B and ab8A OSNs, respectively. Next, we generated double labeling crosses with Gr64b and observed co-expression of Gr64b with Or47a, which is expressed in the ab5B neuron. To elucidate the functional role of Gr64b co-expressed with Or47a, we challenged Or47a-expressing OSNs in wild type and Gr64b–/– mutant flies with odor stimulation using the single sensillum recording technique in two satiation states (fed and starved). Notably, we did not observe any significant odor sensitivity or specificity changes in Gr64b mutants as compared to wild type flies. Taken together, our results reveal co-expression of GRs with ORs in olfactory sensory neurons, while the functional contribution of the GR in this context remains obscure.

Comparative larval ultramorphology of three endemic Lathrobium (Glyptomerus) species (Coleoptera, Staphylinidae, Paederinae) from the Eastern Alps in Italy.

The paper describes the mature larvae (L2) of Lathrobium alzonai, L. freyi and L. paceiendemic, depigmented, apterous and subanophthalmous rove beetles from the Eastern Alps in Italy (Coleoptera: Staphylinidae; Paederine)belonging to the subgenus Glyptomerus. The larva of Lathrobium pacei Piva, 1994 is described for the first time, whereas the larvae of L. alzonai Capra Binaghi, 1938 and L. freyi Koch, 1938 are redescribed. Detailed illustrations of their structural features are provided, and diagnostic larval - morphological characters for Lathrobium are proposed. Based on earlier published and new data, morphological comparisons, both intergeneric (between Lathrobium and Tetartopeus) and interspecific (between L. alzonai, L. freyi and L. pacei) within the subtribe Lathrobiina, are made. The principal differences among the genera and species involve particular structures of the head and their measurements. The generic status of Tetartopeus was confirmed. No clear differences in the external morphological structure between the larvae of Glyptomerus and Lathrobium s.str. were noted. The morphological structure of L. alzonai larvae differed significantly from that of the larvae of the other two species. The differences relate mainly to the much larger body size of L. alzonai, the shape of the head with its relatively narrow neck, the details of the mouthparts structure and the distinct elongation of its antennae, maxillary palps, labial palps, some parts of the legs and urogomphi. Distribution of all known Italian glyptomeroid species of the genus Lathrobium is also given.

Predators or Herbivores: Cockroaches of Manipulatoridae Revisited with a New Genus from Cretaceous Myanmar Amber (Dictyoptera: Blattaria: Corydioidea).

Simple SummaryThere are many more wild cockroaches than household species, but they mostly live a similar life to the latter, feeding on dead and inactive organic material, and hiding in confined spaces. Most of the fossil cockroaches are similar to modern ones in their general appearance, so the lifestyle of the fossil species is probably similar to that of modern cockroaches. Years ago, a unique fossil cockroach, Manipulator modificaputis Vršanský and Bechly, 2015, was discovered from Cretaceous Myanmar amber. This species somewhat resembles mantises and was speculated to be a predator. However, this hypothesis is debatable. In the present study, we redescribe Manipulator modificaputis based on new material, and describe a closely related new species, Manipulatoides obscura gen. & sp. nov. We discuss the feeding habit of these species, and consider that they tend to live around and feed on flowers (as occasionally do some modern cockroaches), instead of hunting for prey. So far, no cockroaches specialized in predation have been affirmed.Manipulator modificaputis Vršanský and Bechly, 2015 (Manipulatoridae, Corydioidea) is a purported predatory cockroach from Cretaceous Myanmar amber, based on a single male. It is distinctive by the nimble head, elongate pronotum and legs, and particularly by the extraordinarily long maxillary palpi. In the present study, we redescribe Manipulator modificaputis based on six new fossils including males and females, and comment on the original description. The closely related Manipulatoides obscura gen. & sp. nov. is proposed on the basis of five fossils, including males and females. It differs from Manipulator in weaker spination of the legs, including the type-C forefemoral spination instead of the type-A of Manipulator. Some undetermined adults and nymphs are also described. We discuss the ethology of Manipulatoridae and speculate that they might feed on flowers. They are unlikely to be specialized predators since they lack necessary weaponry for capturing prey; in contrast, their unique morphotype appears to be suitable for efficient foraging and locomotion amid flowering twigs. The possibility of being kleptoparasites of the spider-web is also discussed. In addition, regenerated four-segmented tarsi are found from the new species.

RNA In Situ Hybridization and Immunohistochemistry to Visualize Gene Expression in Peripheral Chemosensory Tissues of Mosquitoes.

Mosquito-borne diseases such as malaria, Zika virus, and dengue virus are a menace to the human population. Although many mosquito species are not attracted to humans and do not feed on blood, human-biting female mosquitoes are strongly attracted to people and use chemosensory cues to identify a suitable host for a blood meal. Mosquitoes need blood components to reproduce, rendering them excellent vectors for blood-borne diseases. The three genera (Culex, Anopheles, and Aedes) responsible for most of these diseases find hosts by using their peripheral sensory organs. These organs include the antennae, maxillary palps, and proboscis. All three contain diverse populations of highly sensitive neurons that express sensory receptors that can detect odorants, temperature, chemicals, and tastants. Although these organs are essential to the host-seeking behavior that results in biting, their small size and thick outer cuticle can hinder typical histochemical analyses. Here, we briefly review the role the peripheral sensory organs play in mosquito behavior. Then, we introduce how to investigate their gene expression profiles using immunohistochemical and RNA in situ approaches for both whole-mount and frozen-section preparations.

RNA In Situ Hybridization of Whole-Mount Mosquito Olfactory Tissues.

This protocol presents a method for RNA in situ hybridization of whole-mounted preparations of mosquito antennae and maxillary palps. It can be adapted for other peripheral appendages such as the legs or proboscis.

Immunostaining Whole-Mount Olfactory Tissues of Mosquitoes.

Mosquito olfactory tissues are covered in fine hair-like sensory structures called sensilla that house olfactory sensory neurons. This protocol for immunostaining whole-mounted mosquito antennae and maxillary palps enables the visualization of these neurons.

The family Cretapsychidae (Insecta, Trichoptera) from mid-Cretaceous Burmese amber, with descriptions of two new species

The Cretaceous family Cretapsychidae Wichard, 2021 belongs to the superfamily Sericostomatoidea Stephens, 1836 and is characterized by the five-segmented maxillary palps, with the second segment being the longest and the following three segments becoming successively smaller, and the tibial spur formula 2/2/4. In addition, the wing venation is characterized by apical forks II, III, and V in the forewings and forks I, III, and V in the hindwings. The two newly described species (C. kachini sp. nov. and C. myanmari sp. nov.) extend the genus Cretapsyche Wichard, Neumann, Müller & Wang, 2018 to six extinct species, all of which were found in mid-Cretaceous Burmese amber from Kachin State, Myanmar.

A new species of Hyperlasion Schmitz (Diptera: Sciaridae), causing periodic outbreaks in Japan.

A sciarid species, Hyperlasion breviantenna sp. n., is described from Japan. This is the first record of Hyperlasion Schmitz, 1918, from Asia. We compared the molecular sequence data of the mitochondrial cytochrome c oxidase subunit I (COI) region and external morphological characters among congeners and related genera. Morphological features are described and illustrated, and genetic relatedness to selected species with a one-segmented maxillary palpus is shown as a maximum likelihood tree. The DNA barcoding approach revealed that the genetic sequences of Japanese specimens are identical with those of Australian specimens, which have been assigned to the genus Hyperlasion. The new species occurs in outbreaks during the rainy season, June to July, in Japan and is recognized as a nuisance pest. Newly emerged adults appear in the early morning and enter houses, facilities, and public buildings. The biology of the new species is compared with those of H. wasmanni Schmitz, 1918, and Moehnia erema Pritchard, 1960, which have been recorded as occurring in large aggregations with thousands of individuals abroad, based on published biological notes and reports on these species.

A remarkable finding of Centroptilum Eaton, 1869 (Ephemeroptera: Baetidae) in Georgia, Turkey and Iran: one new species evidenced by morphology and DNA

The genus Centroptilum Eaton, 1869 is widely distributed in the West Palaearctic region, but poorly diversified as it previously only encompassed two valid species, C. luteolum (Müller, 1776) and C. pirinense Ikonomov, 1962. The discovery of a new congener, C. volodymyri Martynov, Godunko and Palatov, sp. nov., is therefore remarkable; the new species is described based on larvae collected in Georgia, Turkey and Iran in 2012–2019. This new species can be distinguished by the structure of the cuticle with flattened, stretched shallow, triangular and semilunar-shaped corrugations; scales and their bases densely scattered on body surface; features of the mouth parts, including the presence of an expanded laterally labrum, in combination with segment III of maxillary palp and superlinguae of hypopharynx rounded apically, without any pointed projections at the tip; numerous small teeth scattered proximally in two rows along inner margin of the pretarsal claw; the shape of denticulation along the posterior margin of the abdominal terga, and the number of prominent posterolateral spines on tergum VII; and the shape of gills II–VII, with a distinctly concave posterior margin. Together with a morphological description, data on the distribution and mitochondrial cytochrome c oxidase subunit I gene (COI) barcode sequences of the species are provided. The species delimitation of C. volodymyri Martynov, Godunko and Palatov, sp. nov. and C. luteolum is tested using COI barcode sequences. The data obtained show that the new species can be distinctly recognised as a separate lineage. The habitat preferences associated with the different parts of the area of C. volodymyri Martynov, Godunko and Palatov, sp. nov. are described and compared. Distribution of C. volodymyri Martynov, Godunko and Palatov, sp. nov. confirms the connections between Caucasian and Asian fauna of Ephemeroptera, as already demonstrated in various families and genera. Short notes on the distribution of mayfly species common to the Caucasus, north-western Iran and Central Asia are presented. http://www.zoobank.org/urn:lsid:zoobank.org:act:1D2B7557-0DEC-4ACD-8CA3-A6B50FCC4A51.

Mouthpart structure of the adult Bicaubittacus appendiculatus ( ) (Mecoptera: Bittacidae)

The structure and functional morphology of the mouthparts were investigated in adult hangingfly Bicaubittacus appendiculatus (Esben-Petersen, 1927) by scanning electron microscopy and histological serial sections. The mandibulate mouthparts consist of a labrum-epipharynx, paired mandibles and maxillae, and unpaired labium and hypopharynx. The labrum is elongated and tapered toward the apex. The epipharynx is furnished with numerous sensilla. The mandibles are sword-shaped, with an outer sharp tooth curved mesad and an inner blunt corner. The basal region of each mandible processes a conical projection. The maxillae are well-developed, each consisting of a sclerotized cardo, an elongated stipes, which bears an inner lacinia, an outer galea, and laterally a five-segmented maxillary palp. The labium is formed by a postmentum, a prementum and a pair of two-segmented labial palps. The hypopharynx is concave inward on the anterior side, with numerous microtrichia on the posterior surface. Seven types of sensilla were found on the mouthparts: sensilla basiconica on the epipharynx, and maxillary and labial palps; sensilla chaetica on the epipharynx; sensilla palmata, sensilla placoidea and sensilla trichodea on the epipharynx and maxillary palp; sensilla campaniformia and hair plates on the basal joints of palps. The sensillar function and the feeding mechanism of mouthparts in bittacids are briefly discussed.

Morphological characteristic of malaria vector Anopheles aconitus (Family: Culicidae) revealed by advanced light and scanning electron microscope

Abstract. Supriyomo, Soviana S, Novianto D, Musyaffa MF, Tan S, Hadi UK. 2022. Morphological characteristic of malaria vector Anopheles aconitus (Family: Culicidae) revealed by advanced light and scanning electron microscope. Biodiversitas 23: 3546-3552. Anopheles aconitus (An. aconitus) is one of the primary vectors for malaria in several areas in Indonesia, especially in Java Island. Scanning electron microscope (SEM) is a powerful tool that can differentiate Anopheles spp. Morphology that is difficult to identify by using a light microscope only. The adult of An. aconitus used in this study have been reared in the laboratory. This research is conducted to better understand the Anopheles aconitus' external morphology, such as the head, proboscis, wings, thorax and legs, using advanced light and SEM. Results from an advanced light microscope showed that An. aconitus has palpus with the same length as proboscis with one narrow basal end and two broad distal ends; meanwhile, the apical half of proboscis is pale. Anopheles aconitus has wings with four pale spots on the costa side. Legs are uniformly dark with only very narrow, rather faint pale bands at the joining of segments. Using SEM, we found several types of sensilla trichodea: short-sharp tipped, short-blunt tipped, and long-shaped tipped in antenna, apical proboscis, maxillary palps, abdomen, and legs. Antenna is also covered with microtrichia and sensilla. This research is important for basic necessity in fully understanding and determining of mosquito bionomic due to the development of effective and efficient mosquito vector control strategies.

Partial masculinization of Aedes aegypti females by conditional expression of Nix.

BackgroundAedes aegypti, the main vector of dengue, yellow fever, and other arboviruses thrives in tropical and subtropical areas around the globe putting half of the world’s population at risk. Despite aggressive efforts to control the transmission of those viruses, an unacceptable number of cases occur every year, emphasizing the need to develop new control strategies. Proposals for vector control focused on population suppression could offer a feasible alternative method to reduce disease transmission. The induction of extreme male-biased sex ratios has been hypothesized to be able to suppress or collapse a population, with previous experiments showing that stable expression of the male determining factor Nix in A. aegypti is sufficient to convert females into fertile males.Methodology/Principal findingsHere, we report on the conditional expression of Nix in transgenic A. aegypti under the control of the tetracycline-dependent (Tet-off) system, with the goal of establishing repressible sex distortion. A masculinization phenotype was observed in three of the seven transgenic lines with females exhibiting male-like long maxillary palps and most importantly, the masculinized females were unable to blood feed. Doxycycline treatment of the transgenic lines only partially restored the normal phenotype from the masculinized transgenic lines, while RT-qPCR analysis of early embryos or adults showed no correlation between the level of masculinization and ectopic Nix expression.Conclusions/SignificanceWhile the conditional expression of Nix produced intersex phenotypes, the level of expression was insufficient to program full conversion. Modifications that increase both the level of activation (no tet) and the level of repression (with tet) will be necessary, as such this study represents one step forward in the development of genetic strategies to control vector-borne diseases via sex ratio distortion.

A new species of Thraulus Eaton, 1881 (Ephemeroptera: Leptophlebiidae) from the Western Ghats, South India

Thraulus jacobusi sp. n. is described based on the nymphs collected from the Veerapandi River in the south of the Western Ghats. Thraulus jacobusi sp. n. may be distinguished from other oriental species of Thraulus Eaton, 1881 by the following combination of characters in the nymphs: labial palp ratio, maxillary palp ratio of segments II and III, the colouration of legs, shape and denticulation of claws, shape of tergalius I, and posterolateral spines on the tergum VIII and IX. Nymphal diagnostic keys to Indian species of Thraulus are provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:69019BD1-BE64-4186-8DA9-C67D28DD6135

Homalenchodes, a new genus of Serropalpini from mid-Cretaceous amber of northern Myanmar (Coleoptera: Tenebrionoidea: Melandryidae)

A new fossil genus and species of the family Melandryidae, Homalenchodes jarzembowskii Li, Hsiao, Yoshitomi & Cai gen. et sp. nov., is described and illustrated from the mid-Cretaceous Burmese amber. Homalenchodes is likely closely related to the serropalpin genus Enchodes LeConte, based on their simple maxillary palps, complete prosternal process, exposed protrochantins, ventrally lobed penultimate metatarsomeres, and absence of transverse rows of bristles or spines along the meso- and metatibiae.

A new species of Tricorythodes Ulmer from Colombia and additional notes on T. serratus (Baumgardner amp; vila) (Ephemeroptera: Leptohyphidae).

A new species of Tricorythodes is described and illustrated based on nymphs from Colombia. Legs, mouthparts and other parts of the body were photographed through SEM and molecular characterization was performed by amplification of the COImt gene. Tricorythodes carare sp. nov. shows close affinities with T. serratus (Baumgardner vila), both sharing a similar coloration pattern and the presence of chalazae on femora. The new species can be distinguished from T. serratus and all the species of the genus by the following combination of characters: maxillary palp 3-segmented, with apical setae; dorsal surface of median and hind femora with a longitudinal row of 5 to 9 chalazae serrated in the apex, tarsal claws with 4 or 5 marginal denticles and with 13 submarginal denticles; posterior margin of the abdominal terga with serrated chalazae in the apex. SEM images and distance analysis of the partial sequences of the COI gene were useful to discriminate the new species from T. serratus (genetic divergence 1719%). An additional undescribed species of this group is reported from Esmeraldas in Ecuador and for the departments of Sucre and Choc in Colombia, but it is not described here because of the low number of individuals and the lack of DNA integrity. What is known under the name Tricorythodes serratus is suspected to be a species complex.

First fossil record of Brachyptera (Plecoptera: Taeniopterygidae) in Eocene Baltic amber

The extant taeniopterygid genus BrachypteraNewport, 1848 is reported from the Eocene Baltic amber for the first time. A new species, Brachyptera dewalti n. sp. (Plecoptera: Taeniopterygidae), is described and illustrated based on a well-preserved female in the amber, distinguished by the presence of three well-developed ocelli, the dark color of antennae, maxillary palps, head, prothorax, and abdominal segments, the CuA vein of forewing with three branches, the nearly rhombus, dark brown postgenital plate, and the four-segmented cerci. It is the fourth taeniopterygid species known from the Baltic amber.