Abdominal Setae Research Articles

Bacterial dynamics and biotic sources in the developing swimming crab embryos

The microbial community associated with aquatic animals begins to assemble from the embryonic stage and plays a vital role in their growth and survival. However, the microbial community of the swimming crab Portunus trituberculatus during its embryonic period has not yet been studied. In this study, we investigated the embryonic bacterial community (EBC) of this species across the developmental cycle to elucidate its longitudinal dynamics and biotic sources. The results showed that the diversity of the EBC decreased with host development. The composition of the EBC varied across embryonic development, with a high percent of persistent bacteria and the gradual replacement of γ-Proteobacteria (mainly Oceanospirillaceae and Colwelliaceae) by α-Proteobacteria (Rhodobacteraceae and Flavobacteriaceae) as the major signatures of the succession patterns. Moreover, the unique amplicon sequence variants (ASVs) exhibited the highest functional potentials at the cleavage stage, whereas the shared ASVs did so at the later stages. Furthermore, maternal tissue, mainly the ovary and abdominal setae, contributed the most to the EBC, while rearing water contributed minimally. Overall, our results reveal succession patterns and biotic sources of EBC during the developmental cycle, highlighting that the dominance of embryonic bacteria starts from the early stage of embryo and bacterial vertical transmission is of significance during embryonic development. We also suggest the necessity of microbial management from maternal crabs.

Description of the larva of Cybisterlewisianus Sharp, 1873 (Coleoptera, Dytiscidae, Cybistrinae).

We describe for the first time, the larvae of Cybister (Cybister) lewisianus Sharp, 1873, an endangered species of diving beetle in Japan, emphasizing the chaetotaxy of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. Cybisterlewisianus larvae are characterized by a longer third article of antenna 3 than the sum of the first and second articles; rounded apex of parietal setae 1-3; labium seta 8 absent; elongated trochanter seta 4, not multi-branched; rounded apex of abdominal setae 1, 12, and 13 (instar I); narrow lateral projections of the frontoclypeus; pronotum without two dark-brown longitudinal stripes dorsally (instar III); and the base of the thick row of small setae on the inner edge of the mandible angulate and projecting medially (all instars).

Biomechanical adaptations enable phoretic mite species to occupy distinct spatial niches on host burying beetles.

Niche theory predicts that ecologically similar species coexist by minimizing interspecific competition through niche partitioning. Therefore, understanding the mechanisms of niche partitioning is essential for predicting interactions and coexistence between competing organisms. Here, we study two phoretic mite species, Poecilochirus carabi and Macrocheles nataliae that coexist on the same host burying beetle Nicrophorus vespilloides and use it to 'hitchhike' between reproductive sites. Field observations revealed clear spatial partitioning between species in distinct host body parts. Poecilochirus carabi preferred the ventral side of the thorax, whereas M. nataliae were exclusively found ventrally at the hairy base of the abdomen. Experimental manipulations of mite density showed that each species preferred these body parts, largely regardless of the density of the other mite species on the host beetle. Force measurements indicated that this spatial distribution is mediated by biomechanical adaptations, because each mite species required more force to be removed from their preferred location on the beetle. While P. carabi attached with large adhesive pads to the smooth thorax cuticle, M. nataliae gripped abdominal setae with their chelicerae. Our results show that specialist biomechanical adaptations for attachment can mediate spatial niche partitioning among species sharing the same host.

Toxicity and synergistic activity of compounds from essential oils and their effect on detoxification enzymes against Planococcus lilacinus.

Mealybug, Planococcus lilacinus Cockerell, is a primary surface-feeding insect pest of fruit and flowering plants and also transmits plant viruses, resulting in economic crop loss. Inappropriate and recurrent use of pesticides for mealybug control results in resistance building and deleterious effects on humans and the environment. Essential oils are the most excellent choice for insecticides. Insecticidal activities of pure compounds of essential oils against P. lilacinus are not reported. The present study aims to study the insecticidal activities of some pure active compounds and their binary mixture's action by topical application against P. lilacinus. Results showed that the pure compounds of L-limonene, β-myrcene, and ocimene revealed toxicity (each at LD50 = 0.37 µg/insect) after 96h. The binary mixtures of geraniol + L-menthol and L-limonene + geraniol exhibited synergistic effects (each at LD50 = 0.03 µg/insect) after 96h. The monoterpenes of ocimene and β-myrcene at the higher concentration of 5,000 ppm substantially inhibited the detoxification enzyme activities of AChE (0.93 and 0.78 mU/mg, respectively) and GST (2.19 and 7.29 nmol/min/ml, respectively) in P. lilacinus after 48h. SEM analysis reported the significant anomalies on the morphology of abdominal cuticle, setae, and thoracic leg after 96-h treatment with ocimene at 1,250 ppm against P. lilacinus. Based on the results, the tested pure compounds and their combinations can be suggested for the control of mealybugs.

New whitefly genus and species (Hemiptera, Aleyrodidae) breeding on Orophea katschallica Kurz in India

A new whitefly genus, Rudisculptus gen. nov. is described for its type species Rudisculptus caudalis gen. et sp. nov. feeding on Orophea katschallica Kurz (Annonaceae) from the Andaman Islands, India. Rudisculptus gen. nov. is similar to the New World genus, Aleuropleurocelus Drews & Sampson, 1956 and an Old World genus, Tetralicia Harrison, 1917 in pupal morphology, but differs in having the first abdominal setae, thoracic tracheal pores, caudal furrow, differentiated cephalothorax in slide mounts, the lingula excluded beyond the vasiform orifice. The new genus also differs from an Old World genus, Regiominutus Dubey, 2021 in habitus, pattern of wax secretion, shape, size, cuticle colour, raised lateral margin, extension of segment sutures and the lingula reaching outside the margin of the vasiform orifice, and in having the thoracic tracheal folds. Orophea katschallica is recorded as a new host plant for the whiteflies. Images of puparial habitus and types, line drawings and scanning electron microscope (SEM) microphotographs are provided.

Morphological, genetic and biological differences in two populations of Aleyrodes proletella from northwestern China

The cabbage whitefly Aleyrodes proletella L. (Hemiptera: Aleyrodidae) is a serious pest of vegetables and horticultural crops and invaded Xinjiang in northwestern China in 2013. In 2016, the author observed a whitefly population “Loaded” type which was different from the typical A. proletella in the morphology of eggs, nymphs, pupae and adults. This phenomenon has not been previously documented. The aim of this study is to determine whether the two types constitute separate gene pools using morphological comparisons, genome sequencing and mating experiments. We found that the mycetome color in the “Bare” type was light yellow, the length of the first abdominal setae was 15 μm and the nymphs were directly shed by the ecdyses. The back of the “Loaded” type was covered by ecdyses in an imbricate pattern with the first abdominal setae concatenate. The mycetomes were orange-red and the length of the first abdominal setae was 200 μm. Multiple sequence alignments of the mitochondrial DNA Cytochrome c oxidase subunit I (mtDNA COI) genes were 91.42% identical while the homology of the ribosomal DNA internal transcribed spacer 1 (rDNA ITS1) region was 89.64% (Gap=15.91%). Reciprocal crosses at both the individual and population levels indicated reproductive isolation between the two types since all crosses failed to produce female offspring. Although there are significant differences between these two types, considering the still rather weak evidence of specific diversity, further work is required to satisfactorily assess their taxonomic status.

External and Internal Changes Induced by Parasitic Sacculina leptodiae (Sacculinidae) on the Xanthid Crab, Leptodius exaratus (Xanthidae: Brachyura) from the Red Sea and Gulfs of Suez and Aqaba, Egypt

The externae of parasitic sacculind, Sacculina leptodiae (Sacculindae: Rhizocephala: Cirripedia) on the xanthid crab, Leptodius exaratus (Xanthidae: Brachyura) were recorded during this study. A total of 691 individuals (400 males and 291 females) of this crab were collected from the intertidal coasts of the Egyptian Red Sea, Gulf of Suez and Gulf of Aqaba, of them 38 (23 males and 15 females) were infected with this parasite. The overall infection rate recorded 5.50% for all populations and was slightly higher in males (5.75%) than in females (5.15%). It showed seasonal, spatial and sex variations, recorded the highest rate (7.91%) at Gulf of Suez, declined sharply to 3.85 % at Gulf of Aqaba, and 2.43 % at all populations of the Red Sea, recorded the minimum rate of 0.57% at the southern populations. Autumn has the highest rate (10.34 %) at Hurghada (northern Red Sea), followed by summer with 9.34 % and 7.69 % at the Gulf of Suez and Ras Mohammed (Northern Red Sea), respectively, declined to 2.94 % in summer at Gulf of Aqaba, but increased again to 5.56% during spring. A total of 41 externae were recorded on the infected individuals, comprised 35 individuals with single externa (92.11 %), and only three with double externe (7.89 %). The highest number of externae was 13 (31.70 %) occurred on the 6th abdominal segment, followed by 11 (26.82 %) on the 5th segments, declined to 1-5 on the other segments except the first. The size of externae varied from 1.0 to 10.4 mm in breadth, averaged 5.19± 2.76 mm in males and 5.63± 3.17 mm in females. The rootlets of internae of the parasite invaded ovaries, testes, hepatopancreas, and all spaces within the crab body cavities. The disappearance or destruction of testes in infected males accompanied by remarkable broadness and segmentation of abdomens fringed with dense and length setae lead to “Parasitic castration”, compared with a hyperfiminzation in infected females due to the destruction of undeveloped ovaries and increasing abdominal setae dense and length.

Reinertia, a New Subgenus of the Genus Aedes Meigen and Its Type Species Aedes (Reinertia) suffusus (Diptera: Culicidae), Newly Recorded From Bhutan

A new subgenus, Reinertia Somboon, Namgay & Harbach, of the genus Aedes Meigen and its type species, Ae. suffusus Edwards, are described from specimens reared from larvae and pupae found in a tree hole in Bhutan. The scutum of the adults is mostly covered with narrow pale falcate scales. The proboscis, maxillary palpus, tibiae, and tarsi are dark-scaled. The gonocoxite of the male genitalia bears a unique setose basomesal sclerite. The larva closely resembles larvae of the subgenus Downsiomyia Vargus in having setae 4-6-C with numerous branches and inserted more or less on level with seta 7-C, abdominal seta 12-I is present and the comb is composed of 6-10 spine-like scales arranged in an irregular row. Surprisingly, Reinertia shares features of the adult habitus, male genitalia, and larva with the Palearctic subgenus Dahliana Reinert, Harbach & Kitching. However, in phylogenetic analyses of the mitochondrial COI gene of species representing 38 subgenera of Aedes and six other genera of the tribe Aedini Neveu-Lemaire, Reinertia was not associated with Dahliana or Downsiomyia. In both maximum likelihood and Bayesian analyses of the data, Ae. suffusus was recovered as the weakly supported sister of a clade composed of five species of the subgenus Protomacleaya Theobald. In the absence of strong support, and because Protomacleaya is an unnatural group of species that resemble each other phenetically by virtue of what they lack, Ae. suffusus cannot be placed in the subgenus Protomacleaya. Thus, the morphological and molecular data attest the uniqueness of Ae. suffusus and its recognition as a monobasic subgeneric lineage.

Identification keys to the Anopheles mosquitoes of South America (Diptera: Culicidae). II. Fourth-instar larvae

BackgroundAccurate species identification of South American anophelines using morphological characters of the fourth-instar larva is problematic, because of the lack of up-to-date identification keys. In addition, taxonomic studies, employing scanning electron microscopy of the eggs and DNA sequence data, have uncovered multiple complexes of morphologically similar species, and resulted in the resurrection of other species from synonymy, mainly in the subgenus Nyssorhynchus. Consequently, the identification keys urgently need to be updated to provide accurate morphological tools to identify fourth-instar larvae of all valid species and species complexes.MethodsMorphological characters of the fourth-instar larvae of South American species of the genus Anopheles were examined and employed to elaborate a fully illustrated identification key. For species for which no specimens were available, illustrations were based on published literature records.ResultsA fully illustrated key to the fourth-instar larvae of South American species of the genus Anopheles (Diptera: Culicidae) is presented. Definitions of the morphological terms used in the key are provided and illustrated.ConclusionsMorphological identification of South American Anopheles species based on the fourth-instar larvae has been updated. Characters of the spiracular apparatus were determined useful for the identification of morphologically similar species, in the Strodei Group and some taxa in the Myzorhynchella Section. The single versus branched abdominal seta 6-IV used to differentiate Myzorhynchella species from other Nyssorhynchus species was shown to be variable in Myzorhynchella species. Also, the abdominal setae 1-IV,V of Anopheles atacamensis and Anopheles pictipennis were shown to be slightly serrate at the edges. Recognition of this character is important to avoid inaccurate identification of these species as members of the subgenus Anopheles.

New genus and species of whitefly, Margaritaplena ovata gen. et sp. nov. (Hemiptera: Aleyrodidae) from the Andaman Islands, India

ABSTRACT Puparia of a new whitefly genus and species, Margaritaplena ovata gen. et sp. nov. found feeding on the underside of the leaves of Combretum sp. (Combretaceae) are described from the Andaman Islands, India. It differs from the allied genera, Asialeyrodes Corbett, Icfrealeyrodes Dubey and Sundararaj, and Vasantharajiella PMM David in shape, the large-sized geminate pores, and thoracic and caudal tracheal pores comprising microtubercles, and are inset from the margin, and also from Asialeyrodes in a complete submarginal furrow, and in lacking the first abdominal setae and caudal furrow. Line drawings, images for the habitus, types, and scanning electron microscope photomicrographs are provided for the new taxa. An identification key to puparia differentiating the new genus from related Indian Aleyrodinae genera is given. http://www.zoobank.org/urn:lsid:zoobank.org:pub:705651F8-C3AD-45F2-ACE9-0C434625C904

Molecular and morphological evidence of sibling species in Anopheles baileyi Edwards (Diptera: Culicidae) in Bhutan and Thailand

This paper reports the results of a molecular and morphological study of Anopheles baileyi in Bhutan and Thailand. Phylogenetic analyses of ribosomal (ITS2) and mitochondrial DNA (COI) sequences revealed the presence of four genetically distinct clades, three in Bhutan (Clades I, II and III) and one in Thailand (Clade IV). Most of the larvae in the Bhutanese clades differed from those in the Thai clade in having seta 4-C branched, whereas it is single in the latter. The adults of each clade showed variation of wing markings and overlapping characters. The combination of characteristics of thoracic setae 1,2-P and abdominal seta 3-I was found to be useful for distinguishing the larvae. Pupae were inseparable. We provisionally recognize mosquitoes of Clades I, II, III and IV as members of a sibling species complex, the Baileyi Complex, denoted as species A, B, C and D, respectively. Species A is most likely the type form of An. baileyi s.s. because it was found adjacent to the type locality (Yatung, Tibet), and the others are unrecognized species.

Male-biased Adult Production of the Striped Fruit Fly, Zeugodacus scutellata, by Feeding dsRNA Specific to Transformer-2.

Sterile insect release technique (SIT) is effective for eradicating quarantine insects including various tephritid fruit flies. When SIT is used for fruit flies, it is challenging to remove females from sterile males due to oviposition-associated piercing damage. This study developed a sex transition technique by feeding double-stranded RNA (dsRNA) specific to a sex-determining gene, Transformer-2 (Zs-Tra2) of the striped fruit fly, Zeugodacus scutellata. Zs-Tra2 is homologous to other fruit fly orthologs. It is highly expressed in female adults. RNA interference (RNAi) of Zs-Tra2 by injecting or feeding its specific dsRNA to larvae significantly increased male ratio. Recombinant Escherichia coli cells expressing dsRNA specific to Zs-Tra2 were prepared and used to feed larvae to suppress Zs-Tra2 gene expression levels. When these recombinant bacteria were fed to larvae during the entire feeding stage, the test population was significantly male-biased. Some females treated with such recombinant E. coli exhibited mosaic morphological characters such as the presence of male-specific abdominal setae in females. This study proposes a novel technique by feeding dsRNA specific to Transformer-2 to reduce female production during mass-rearing of tephritid males for SIT.

Description of a new whitefly, Pealius satakshiae Dubey (Hemiptera: Aleyrodidae), infesting Quercus leucotrichophora (Fagaceae) in the Western Himalaya, India

ABSTRACTA new whitefly species, Pealius satakshiae Dubey, found infesting Quercus leucotrichophora A. Camus (Fagaceae) in the Chail Wildlife Sanctuary, Himachal Pradesh, India, is described. Puparia of the new species differ from described Pealius species in being larger in size, having a differentiated cephalus, rhachisform abdomen and reduced abdominal segment VII, and lacking the first abdominal setae. Puparial characteristics for the genus Pealius Quaintance and Baker in relation to new species are discussed. Camera lucida drawings, images of habitus and holotype, and scanning electron microscope photomicrographs are provided.http://www.zoobank.org/lsid:zoobank.org:pub:9712A865-4DD6-457B-84B0-1C7873316DE4

Morphological and molecular evidence for a new species of Lutzia (Diptera: Culicidae: Culicini) from Thailand

We found a species of LutziaTheobald (1903) (Diptera: Culicidae) in Chiang Mai Province and other provinces in northern Thailand which bears morphological and DNA sequence differences from the three species of Lutzia, subgenus Metalutzia Tanaka, previously recorded from Thailand, namely Lt. fuscana (Wiedemann), Lt. halifaxii (Theobald) and Lt. vorax Edwards. The adults of the Chiang Mai form (CM form) have abdominal banding patterns similar to those of Lt. vorax from Japan (which includes the type locality of this species), but differ in having the mediocubital crossvein usually positioned before rather than beyond the radiomedial crossvein. The thoracic and abdominal integument of Lt. vorax larvae is covered with relatively short pointed spicules whereas it is covered by denser, longer and more acutely pointed spicules in the CM form. Some differences are also found in the development of thoracic seta 1-M, and abdominal setae 8-II and 8-III. The pupa of the CM form clearly differs from the pupa of Lt. vorax in having setae 1 and 5 of abdominal segments V and VI branched rather than single. The characters of the wing, larva and pupa of the CM form are similar to those of Lt. fuscana and Lt. halifaxii. However, whereas the phallosome of males of the CM form is similar to males of Lt. vorax and Lt. halifaxii, it is distinct from males of Lt. fuscana. Phylogenetic analysis of mitochondrial cytochrome c oxidase subunits I and II sequences revealed that the CM form falls outside a clade comprised of specimens of Lt. vorax from Japan, Korea, Thailand and Bhutan (Kimura 2-parameter, K2P, genetic distances 3.9–5.6, and 5.1–6.6, respectively). However, the two gene sequences of the CM form are not clearly distinct from clades comprised of sequences from specimens of Lt. fuscana and Lt. halifaxii (K2P 0.2–2.4%). However, based on the combination of morphological and molecular data, the current study provides evidence that the CM form is a previously unrecognized species of the genus Lutzia.

Genetic Variation and Differentiation of Hylesia metabus (Lepidoptera: Saturniidae): Moths of Public Health Importance in French Guiana and in Venezuela.

Hylesia moths impact human health in South America, inducing epidemic outbreaks of lepidopterism, a puriginous dermatitis caused by the urticating properties of females' abdominal setae. The classification of the Hylesia genus is complex, owing to its high diversity in Amazonia, high intraspecific morphological variance, and lack of interspecific diagnostic traits which may hide cryptic species. Outbreaks of Hylesia metabus have been considered responsible for the intense outbreaks of lepidopterism in Venezuela and French Guiana since the C20, however, little is known about genetic variability throughout the species range, which is instrumental for establishing control strategies on H. metabus. Seven microsatellites and mitochondrial gene markers were analyzed from Hylesia moths collected from two major lepidopterism outbreak South American regions. The mitochondrial gene sequences contained significant genetic variation, revealing a single, widespread, polymorphic species with distinct clusters, possibly corresponding to populations evolving in isolation. The microsatellite markers validated the mitochondrial results, and suggest the presence of three populations: one in Venezuela, and two in French Guiana. All moths sampled during outbreak events in French Guiana were assigned to a single coastal population. The causes and implications of this finding require further research.

Early Evolution of Specialized Termitophily in Cretaceous Rove Beetles

Termitophiles, symbionts that live in termite nests, include a wide range of morphologically and behaviorally specialized organisms. Complex adaptive mechanisms permit these animals to integrate into societies and to exploit their controlled physical conditions and plentiful resources, as well as to garner protection inside termite nests. An understanding of the early evolution of termitophily is challenging owing to a scarcity of fossil termitophiles, with all known reliable records occurring from the Miocene (approximately 19 million years ago [mya]) [1-6], and an equivocal termitophile belonging to the largely free-living Mesoporini from the mid-Cretaceous [7]. Here we report the oldest, morphologically specialized, and obligate termitophiles from mid-Cretaceous Burmese amber (99 mya). Cretotrichopsenius burmiticus gen. et sp. nov. belongs to Trichopseniini, a group of distinctive termitophilous aleocharine rove beetles, all of which possess specialized swollen or horseshoe-crab-shaped body plans. Cretotrichopsenius display the protective horseshoe-crab-shaped body form typical of many modern termitophiles, with concealed head and antennae and strong posteriorly directed abdominal setae. Cretotrichopsenius represent the earliest definitive termitophiles, shedding light on host associations in the early evolution of termite societies. The fossil reveals that ancient termite societies were quickly invaded by beetles and by multiple independent lineages of social parasites over the subsequent eons.

Distinguishing features of immature stages of Panchaetothripinae (Thysanoptera: Thripidae) known in New Zealand

ABSTRACTDiagnostic morphological characters of the juvenile Panchaetothripinae in New Zealand are illustrated. Keys developed enable colonies with only immature stages to be identified without needing to rear adults. Live larvae or larvae in ethanol are distinguished by the presence of expanded tips of body setae (Parthenothrips dracaenae), the absence of setae at the abdomen tip (Hercinothrips bicinctus), setae at abdomen tip not longer than abdominal tip width (Heliothrips haemorrhoidalis) and abdominal tip setae longer than abdominal tip width (Sigmothrips aotearoana, endemic species). The presence or absence of spine-like setae on abdominal segments 9 and 10, and the number and length of setae on the wing buds, enable identification of pupae. Abdominal spine-like setae were on the prepupa and pupa of H. bicinctus and S. aotearoana, species that pupate off the plant, and are probably defensive structures. This is the first record of spine-like setae on segment 10 of terebrantian pupae.

Description of a new species of Metabemisia Takahashi, 1963 from China (Hemiptera, Aleyrodidae).

A new whitefly species, Metabemisia leguminosa sp. n., collected from an undetermined leguminous herb is described from Wuzhishan Mountain, Hainan Island, China. The puparium of the new species differs from that of all other Metabemisia species by the presence of 4–5 rows of very small distinct papillae along the margin, the absence of the first abdominal seta, and the indistinct thoracic tracheal pores. An identification key to the worldwide species of Metabemisia is provided.

The oldest tachyporine rove beetle in amber (Coleoptera, Staphylinidae): A new genus and species from Upper Cretaceous Burmese amber

A new genus and species of extinct rove beetle, Procileoporus burmiticus gen. and sp. n., is described from Upper Cretaceous Burmese amber (Cenomanian; ca. 99 Ma). Due to the condition of the fossil, parts of the body could not be examined, but sufficient characteristics were visible to allow the specimen to be placed within the subfamily Tachyporinae (tribe Tachyporini). Procileoporus is most similar to the extant genus Cileoporus Campbell in having a slender abdomen, but it differs in having much shorter abdominal setae, prominent striated microreticulation on the elytra, non-lobed tergite VIII, and in other details of the male genital segments. This is the first tachyporine rove beetle from Burmese amber and the oldest record of the subfamily in amber. The evolution of sexual dimorphism in the genital segments is briefly discussed.

The immature stages of Micropygomyia (Coquillettimyia) chiapanensis (Dampf) (Diptera: Psychodidae, Phlebotominae).

The egg exochorion, larval instars and pupa of the phlebotomine sand fly Micropygomyia (Coquillettimyia) chiapanensis (Dampf) are described and illustrated based on specimens collected in the locality of Farallón, municipality of Actopan, Veracruz, Mexico. Morphology of fourth instar larval mouthparts, particularly the incisor lobe and molar lobe shape of mandible, could be important for species identification of immature Phlebotominae. In this work is compared the pupal chaetotaxy of Mi. chiapanensis with other species previously described. The fourth instar larva of Mi. chiapanensis is compared with other species of this genus, the most important differentiating characters being the size, shape and position of the abdominal dorsal internal seta.