Antennal Segment Research Articles

Těžba lesního porostu ovlivňuje fenotyp živočichů: případová studie fluktuující asymetrie u střevlíka Notiophilus rufipes (Coleoptera: Carabidae)

We compared the rate of variability in the size of different body parts among three different treatments created by forest management (i.e. clearing, pole-stage stand, ecotone) in the Podyji National Park (Czech Republic). In order to describe changes, we used bioindicative values of the Carabidae (Coleoptera) with the example of Notiophilus rufipes (Curtis, 1829). We conducted fluctuating asymmetry (FA) of ten important metrical traits (e.g. antennal segments, length and width of third palpomer of the labial palpus). We found that specimens have sex specific association to FA of second antennal segment. The interaction of sex and treatment negatively affects the distribution of FA in polestage stand. We revealed that males had higher level of FA in pole-stage stand than females. Ecotones are zones where individuals from diverse habitats interact. Model of FA, with set sex as random effect, have positive association to litter and negative association to Collembola. This research contributes to forest management strategies by demonstrating how human-induced interventions influence eco-evolutionary link between stress and disturbance. The research suggests that for forest management, forest openings in thermophilic oak stands could support phenotypic variation in rare epigeic species.

Not all male bees posses thirteen antennal segments: New megachilid species from the Afro-Arabian and Afrotropical regions (Apoidea: Anthidiini: Pseudoanthidium) with deviant numbers of segments

Male bees (Apoidea) typically possess antennae with 13 articles, with only a few exceptions reported, none of which are from the Megachilidae family. In this study, we describe two new species of the megachilid tribe Anthidiini that display an unusual characteristic – their males have only 12 antennal segments. We attributed these species, Pseudoanthidium omanicum sp. nov. from the Arabian Peninsula, and P. ethiopicum sp. nov. from Ethiopia, to the subgenus Pseudoanthidium (Mesanthidiellum), previously known only from Sub-Saharan Africa. Notably, the male of a third species in this subgenus, P. (Mesanthidiellum) sakaniense (Cockerell, 1936) was also found to have only 12 antennal segments. Further investigation revealed that males with antennae with 12 articles are also present in the closely related subgenus Pseudoanthidium (Branthidium), suggesting that this phenomenon may be more widespread yet often overlooked. A broader review indicates that deviations from the typical 13 antennal articles are known in 10 genera of bees and account for less than 0.5% of all bee species. We conclude that this trait has evolved independently across different bee lineages. However, the specific function of a reduced number of antennal articles remains elusive. http://www.zoobank.org/urn:lsid:zoobank.org:pub:56B808FB-E4F2-46A9-9B54-850AF83263D0

A new species of Neoergasilus Yin 1956 (Copepoda: Cyclopoida: Ergasilidae) parasitic on the catfish Clarias gariepinus (Burchell, 1822) (Siluriformes: Clariidae) from South Africa

Twenty-one specimens of an ergasilid were collected from the gills of the sharptooth catfish, Clarias gariepinus (Burchell), from the Eastern Cape, South Africa. The first leg and antennae morphology conformed to the genus Neoergasilus Yin, 1956. While the invasive Neoergasilus japonicus (Harada, 1930) is the only Neoergasilus species that has been reported from Africa, the combination of several characteristics, separates the Eastern Cape specimens from N. japonicus and the other eight Neoergasilus congeners. These include an inflated cephalothorax; the presence of an oval dorsal ornamentation anterior to the cephalosome; a spine on the posterodistal margin of the first antennal segment; a cone-like process at the proximal margin of the second antennal segment; a knob-like process on the inner distal margin of the first exopodal segment of leg 1 and two forked spines on the third exopodal segment; leg 4 bearing a 2-segmented exopod and 3-segmented endopod; a single-segmented fifth leg with a seta extending from the base of the pedigerous somite and three unequal setae on its free segment; and a median caudal rami seta with an array of spines. Supporting genetic data were generated using two partial ribosomal RNA genes, 18S and 28S, and one partial mitochondrial DNA gene, COI. The Eastern Cape species is here proposed as new to science and described as Neoergasilus africanusn. sp. (Ergasilidae: Cyclopoida). This is the first Neoergasilus species described from the sharptooth catfish and from the southern hemisphere. Additionally, a key to all the species of this genus is provided.

A severe head louse (Pediculus humanus capitis) infestation: Timeline, pathogen detection, kdr-gene screening and morphological anomalies of lice.

Lice are assuming an increasing importance in forensic investigations, given their capacity to provide information about an individual's care. Head louse pediculosis is a frequent condition in school-age children and can be properly controlled using topical treatments combined with good personal hygiene. Prolonged and chronic infestations may result in more serious outcomes including severe iron deficiency anaemia. We conducted entomological and laboratory investigations of a head louse infestation in a 12-year-old girl who experienced severe anaemia and subsequent death. Numerous lice were found postmortem on the head, face and neck of the patient, as well as on bedding and clothing. Analysis of nits on individual hairs determined that the louse infestation had been present for at least 166 days. The lice had some morphological traits characteristic of body lice: the third antennal segment in some specimens was distinctly longer than wide, and the apices of some paratergal plates did not extend into intersegmental membranes, while other morphological features were characteristic of head or body lice. All lice were heterozygous for the T917I kdr genotype, a marker of permethrin resistance. Nineteen (79.2%, 95%CI 59.5%-90.8%) louse DNA samples tested TaqMan positive for Acinetobacter (Moraxellales; Moraxellaceae) sp. Available information and laboratory findings are further discussed regarding their possible contribution to the negative outcome of this case. We stress the impact head louse pediculosis can have on children with limited parental attention, and how severe head louse infestation may serve as warning sign of neglect, and other high-risk situations.

A NEW SPECIES OF THE GENUS APHIDUROMYZUS UMAROV ET IBRAIMOVA, 1967 (HEMIPTERA: APHIDOMORPHA: APHIDIDAE) FROM KAZAKHSTAN

Aphiduromyzus dzhungaricus Kadyrbekov, sp. n. is described from the South- Eastern Kazakhstan (Dzhungar Alatau). The new species differs from A. rosae Umarov et Ibraimova, 1967 by ratios of processus terminalis to base of VI antennal segment, length of siphunculus to length of cauda, and ultimate rostral segment to base of VI antennal segment, by the presence of marginal tubercles only on the pronotum, I‒IV and VII abdominal segments and quantity of setae on the cauda. A key to apterous and alate viviparous females of the genus Aphiduromyzus Umarov et Ibraimova, 1967 is provided.

Gasteruption slovacum sp. nov. (Hymenoptera: Gasteruptiidae)—a new species of carrot wasp from Central Europe

New species of carrot wasp—Gasteruption slovacum sp. nov.—is described based on a male collected near the village Čenkov in south of Slovakia. This species is similar and phylogenetically related to G. erythrostomum, from which it differs especially by the rough sculpture of mesoscutum, larger occipital carina, longer third and fourth antennal segments and larger total length. This species is also morphologically and in total length similar to G. insidiosum, from which it differs especially by the very small proportion of ivory colouration on legs. Phylogenetically, it forms a group with G. erythrostomum, which is nearest related to the group of G. nigrescens and G. foveiceps.

The families of the suborder Brachycera Schiner, 1862 (Insecta: Diptera): Part 2

Most Diptera belong to the Brachycera, a group characterized by the reduction or fusion of antennal segments to eight or fewer and by modifications to the larval head and mouthparts. The larvae of most species are predatory, although there are a few parasitoid groups as well. From a methodological point of view, the research was conducted using bibliometric and content analysis approaches. Bibliometrics is guided by the principle of analyzing scientific or technical activity through quantitative studies of publications, that is, through this approach. Document analysis was used as a data collection method to gather information from theoretical books, banks, university dissertations, scientific journals, documents, and digital platforms.

Morphological Characterization of the Antenna and Scent Patch of Three Danaus Species (Papilionoidea: Nymphalidae, Danainae).

The scent system of Danaus is important for the study of butterfly sexual communication and relevant investigations in biomimetics due to its involvement with mimicry. Using light, scanning, and transmission electron microscopy, the morphological characteristics of Danaus' antennae and scent patches of the scent system for three species, D. chrysippus, D. genutia, and D. plexippus, were investigated herein. Their apical clubs of the flagellums contain sensilla trichodea, sensilla chaetica, and sensilla coeloconica. The scent patch scales typically have a tree-like structure in its lumen at the nano-scale. Comparisons were made between the androconial scales and the other scales in scent patches. Rank sum tests showed significant differences in scent patch scales' characteristics between the species, as well as in the ultrastructure of antennal segments between species and sexes. Spearman's correlation tests showed significant correlations between the morphological characteristics of androconial scales in scent patches. Moreover, the antennal characteristics were significantly correlated. The morphological characteristics of the females' antennae were significantly correlated with those of the males' antennae and androconial scales. However, the significance and coefficient of these correlations were inconsistent across species and sexes. This study provides fundamental morphological information that helps in understanding the pheromone recognition system of Danaus.

A new genus and new species of sucking louse (Phthiraptera: Anoplura: Enderleinellidae) from the particoloured flying squirrel (Hylopetes alboniger) in Laos, and an updated identification key to enderleinellid genera.

Hylophthirus spinosus, new genus and new species (Phthiraptera: Anoplura: Enderleinellidae), is described from specimens collected from the particoloured flying squirrel, Hylopetes alboniger in Khammouane Province, Laos (Lao Peoples Democratic Republic). Both sexes of the new louse are illustrated with stacked microphotographs, scanning electron micrographs and line drawings. An updated morphological identification key to the six genera (Atopophthirus, Enderleinellus, Hylophthirus, Microphthirus, Phthirunculus and Werneckia) now recognised within the family Enderleinellidae is presented. The new genus is unique within the Enderleinellidae in having massive spines (modified setae) on some abdominal sternites, partially bulbous 5th antennal segments, mesothoracic spiracles borne on protuberances and the morphology of the genitalia of both sexes. Tables showing all genera of sucking lice that include species parasitising sciurids (squirrels, chipmunks, susliks and marmots), and all known species of enderleinellids, with their known host associations and geographical distributions are included and briefly discussed in relation to the new genus and species.

Morphology and distribution of sensilla on head appendages in the water beetle Hygrobia hermanni (Coleoptera: Adephaga: Hygrobiidae).

Sensilla on head appendages were studied in detail for the first time in a member of the relict family Hygrobiidae (squeak beetles), closely related to Dytiscidae (diving beetles). Adult and third instar larval stage specimens of Hygrobia hermanni (Fabricius, 1775) were examined using scanning electron microscopy, focusing on antennae, palps and larval mandibles. In total, 37 sensilla subtypes are described, including 22 observed in the adult (basiconica: 3; Böhm's bristles: 2; circumvallate sensilla: 2; coeloconica: 10; ovoid placodea: 3; digitiform placodea: 2) and 16 in the larva (basiconica: 4; campaniformia: 1; chaetica: 4; coeloconica: 5; trichodea: 1; unnamed: 1). Only one subtype (of sensilla coeloconica) was shared between the adult and the larva. Autapomorphies of Hygrobiidae and Dytiscidae, and putatively shared derived characters (synapomorphies) of Hygrobiidae + Dytiscidae are discussed. Among the latter, the most remarkable is the acquisition of a special sensory field, located on the apical segment of the adult maxillary palp, subapically and postero-dorsally. This sensory field is made up of ovoid multiporous sensilla placodea otherwise present on the anterior (internal) surface of antennal segments, suggesting that in a common ancestor of Hygrobiidae and Dytiscidae, maxillary palps might have taken over enhanced capacities of longe-range molecule detection.

Olfactory system structure and function in newly hatched and adult locusts

An important question in neuroscience is how sensory systems change as animals grow and interact with the environment. Exploring sensory systems in animals as they develop can reveal how networks of neurons process information as the neurons themselves grow and the needs of the animal change. Here we compared the structure and function of peripheral parts of the olfactory pathway in newly hatched and adult locusts. We found that populations of olfactory sensory neurons (OSNs) in hatchlings and adults responded with similar tunings to a panel of odors. The morphologies of local neurons (LNs) and projection neurons (PNs) in the antennal lobes (ALs) were very similar in both age groups, though they were smaller in hatchlings, they were proportional to overall brain size. The odor evoked responses of LNs and PNs were also very similar in both age groups, characterized by complex patterns of activity including oscillatory synchronization. Notably, in hatchlings, spontaneous and odor-evoked firing rates of PNs were lower, and LFP oscillations were lower in frequency, than in the adult. Hatchlings have smaller antennae with fewer OSNs; removing antennal segments from adults also reduced LFP oscillation frequency. Thus, consistent with earlier computational models, the developmental increase in frequency is due to increasing intensity of input to the oscillation circuitry. Overall, our results show that locusts hatch with a fully formed olfactory system that structurally and functionally matches that of the adult, despite its small size and lack of prior experience with olfactory stimuli.

New species of Dermoergasilus Ho & Do, 1982 (Copepoda: Cyclopoida: Ergasilidae) parasitizing endemic cichlid Paretroplus polyactis (Bleeker) in Madagascar.

Dermoergasilus madagascarensis n. sp. is described from the gills of Paretroplus polyactis, an endemic cichlid fish in Madagascar, using a combined morphological (light microscopy and SEM) and molecular approach (partial 18S rDNA, 28S rDNA, and COI sequences). The new species is characterized mainly by possessing: (i) roughly pentagonal cephalosome; (ii) antennal endopodal segments covered with slightly inflated membrane; (iii) maxillule bearing 2 equally long outer setae and a minute inner seta; (iv) interpodal sternites of swimming legs ornamented with 3–4 rows of spinules; (v) genital segment and first abdominal somite both barrel-shaped; and (vi) a caudal ramus projecting into a digitiform process with inconspicuous terminal seta and bearing 3 terminal setae. The obtained DNA sequences of Malagasy species represent the first molecular data for species of Dermoergasilus. The 28S rDNA phylogeny showed the affiliation of D. madagascarensis n. sp. to Ergasilidae and its sister relationship with cosmopolitan Ergasilus sieboldi von Nordmann, 1832. The first checklist for all species of Dermoergasilus is provided.

Characterization of Four Complete Mitogenomes of Monolepta Species and Their Related Phylogenetic Implications.

Monolepta is one of the diverse genera in the subfamily Galerucinae, including 708 species and 6 sub-species worldwide. To explore the information on the mitogenome characteristics and phylogeny of the section "Monoleptites", especially the genus Monolepta, we obtained the newly completed mitochondrial genomes (mitogenomes) of four Monolepta species using high-throughput sequencing technology. The lengths of these four new mitochondrial genomes are 16,672 bp, 16,965 bp, 16,012 bp, and 15,866 bp in size, respectively. All four mitochondrial genomes include 22 transfer RNA genes (tRNAs), 13 protein-coding genes (PCGs), 2 ribosomal RNA genes (rRNAs), and one control region, which is consistent with other Coleoptera. The results of the nonsynonymous with synonymous substitution rates showed that ND6 had the highest evolution rate, while COI displayed the lowest evolution rate. The substitution saturation of three datasets (13 PCGs_codon1, 13 PCGs_codon2, 13 PCGs_codon3) showed that there was no saturation across all datasets. Phylogenetic analyses based on three datasets (ND1, 15 genes of mitogenomes, and 13 PCGs_AA) were carried out using maximum likelihood (ML) and Bayesian inference (BI) methods. The results showed that mitogenomes had a greater capacity to resolve the main clades than the ND1 gene at the suprageneric and species levels. The section "Monoleptites" was proven to be a monophyletic group, while Monolepta was a non-monophyletic group. Based on ND1 data, the newly sequenced species whose antennal segment 2 was shorter than 3 were split into several clades, while, based on the mitogenomic dataset, the four newly sequenced species had close relationships with Paleosepharia. The species whose antennal segment 2 was as long as 3 were split into two clades, which indicated that the characteristic of "antennal segment 2 as long as 3" of the true "Monolepta" evolved multiple times in several subgroups. Therefore, to explore the relationships among the true Monolepta, the most important thing is to perform a thorough revision of Monolepta and related genera in the future.

Functional expression and ligand identification of homo- and heteromeric Drosophila melanogaster CO2 receptors in the Xenopus laevis oocyte system.

Carbon dioxide (CO2) is an important olfactory cue in Drosophila melanogaster and can elicit both attractive and aversive behaviors. It is detected by gustatory receptors, Gr21a and Gr63a, found in the ab1C neuron in basiconic sensilla on the third antennal segment. Volatile substances that modulate the receptors' function are of interest for pest control. While several substances block ab1C neurons or mimic the activating effect of carbon dioxide, it is not known if these substances are indeed ligands of the CO2 receptor or might act on other proteins in the receptor neuron. In this study, we used the recombinant Xenopus laevis expression system and two-electrode voltage-clamp technology to investigate the receptor function. We found that application of sodium bicarbonate evokes large inward currents in oocytes co-expressing Gr21a and Gr63a. The receptors most likely form hetromultimeric complexes. Homomultimeric receptors of Gr21a or Gr63a are sufficient for receptor functionality, although oocytes gave significantly lower current responses compared to the probable heteromultimeric receptor. We screened for putative blockers of the sodium bicarbonate response and confirmed that some of the substances identified by spike recordings of olfactory receptor neurons, such as 1-hexanol, are also blockers in the Xenopus oocyte system. We also identified a new blocking substance, citronellol, which is related to insect repellents. Many substances that activate receptor neurons were inactive in the Xenopus oocyte system, indicating that they may not be ligands for the receptor, but may act on other proteins. However, methyl pyruvate and n-hexylamine were found to be activators of the recombinant Gr21a/Gr63a receptor.

A New Species of Spelaeometra Polhemus & Ferreira, 2018 (Hemiptera: Heteroptera: Hydrometridae) from a Hotspot of Troglobites in Brazil, Serra do Ramalho Karst Area.

Spelaeometra Polhemus & Ferreira, 2018 (Hemiptera: Heteroptera: Hydrometridae) is a monotypic and troglobitic genus, recently described based on material collected in the state of Minas Gerais, Brazil. From specimens collected in the Gruna do Enfurnado Cave in the Serra do Ramalho karst area, municipality of Coribe, state of Bahia, Brazil, we describe Spelaeometra hypogea Cordeiro & Moreira, sp. nov. and compare it with Spelaeometra gruta Polhemus & Ferreira, 2018. The new species is diagnosed by the general body color being pale-yellow to light-brown; antennal segments I and II being subequal in length; the reduced gular lobe, not covering any labial segment; the male proctiger without apical projections; and the male paramere with convex dorsal margin after the curvature, with a narrow hook-like apex.

OLFACTORY RESPONSES OF AULACOPHORA FOVEICOLLIS LUCAS – AN ECOLOGICALLY IMPORTANT PEST - FROM WEST BENGAL, INDIA

Pumpkin, Cucurbita maxima, is severely harmed by Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae), as a major insect pest of the plant. Based on Scanning electron microscopic analysis, compared to mechanosensilla, prevalence of antennal olfactory sensilla, was observed. The number of olfactory sensilla in the circumferential band of IXth antennal segment was higher in female species. Stimulation of the sensilla present on the antennae of A. foveicollis was analyzed by electroantennogram (EAG) at four different concentrations viz. 10.0, 5.0, 1.0, and 0.1 mg/ml in both sexes. The male species displayed greatest peak amplitude at 5mg/mL for heneicosane, whereas the female species displayed maximum peak amplitude at 10.0 mg/mL for 2-methyl phenol followed by 5.0 mg/mL for 1,4-dimethoxybenzene. However, pooled EAG data revealed that GLV elicited the strongest reactions, followed by aliphatic chemicals, oxygenated monoterpenes, hydrocarbon monoterpenes, and sesqueterpenes. These findings univocally shows that the pest's antennal responses clearly displayed sexual dimorphism.

Description of immature stages of Gamostolus subantarcticus (Hemiptera: Heteroptera: Aenictopecheidae) from Tierra del Fuego, Argentina

The immature stages of Gamostolus subantarcticus (Berg, 1883) (Hemiptera: Heteroptera: Aenictopecheidae) are described and compared. Main characteristics to distinguish the nymphs from adults are explained, among which we emphasize the relationship between antennal and rostral segments as important characters for their separation.

Effects of antennal segments defects on blood-sucking behavior in Aedes albopictus.

After mating, female mosquitoes need a blood meal to promote the reproductive process. When mosquitoes bite infected people and animals, they become infected with germs such as viruses and parasites. Mosquitoes rely on many cues for host selection and localization, among which the trace chemical cues emitted by the host into the environment are considered to be the most important, and the sense of smell is the main way to perceive these trace chemical cues. However, the current understanding of the olfactory mechanism is not enough to meet the needs of mosquito control. Unlike previous studies that focused on the olfactory receptor recognition spectrum to reveal the olfactory mechanism of mosquito host localization. In this paper, based on the observation that mosquitoes with incomplete antennae still can locate the host and complete blood feeding in the laboratory, we proposed that there may be some protection or compensation mechanism in the 13 segments of antennae flagella, and only when the antennae are missing to a certain threshold will it affect the mosquito's ability to locate the host. Through rational-designed behavioral experiments, we found that the 6th and 7th flagellomeres on the Aedes albopictus antenna are important in the olfactory detection of host searching. This study preliminarily screened antennal segments important for host localization of Ae. albopictus, and provided a reference for subsequent cell biology and molecular biology studies on these segments. Meanwhile, the morphology and distribution of sensilla on each antenna flagellomere were also analyzed and discussed in this paper.

Two new species of Sminthurididae (Hexapoda, Collembola, Symphypleona) from Brazil with notes on Denisiella Folsom & Mills and Sphaeridia Linnaniemi.

Two new species of Sminthurididae, Sphaeridiapiauiensis Medeiros & Bellini, sp. nov. and Denisiellapiracurucaensis Silva, Medeiros & Bellini, sp. nov. from Piaui state, Brazil, are herein described and illustrated. Sphaeridiapiauiensissp. nov. resembles species of the irmleri group, like S.irmleri Bretfeld & Gauer, S.fibulifera Bretfeld & Gauer, and S.peruensis Bretfeld & Schulz, by its complex male ventral tube without asymmetrical structures or medial process. However, it differs from them by the combination of the male tibiotarsus III with a leaf-shaped IIpe chaeta and a regular IIIpi chaeta, ventral tube with 1+1 chaetae, and the absence cuticular hooks on the furca. Denisiellapiracurucaensissp. nov. resembles its congeners without the nasal organ, especially D.colombiana Ospina & Palacios-Vargas, by the presence of spiniform chaetae at least on the second antennal segment of the females, four serrated spines on tibiotarsus III, and the ventral dens chaetotaxy, but D.piracurucaensissp. nov. differs from the latter especially by the presence of 8+8 eyes and the shape of the male proximal tibiotarsal organ. To describe both species all Neotropical Sphaeridia and all described Denisiella species were surveyed, presenting notes on both genera, comparative tables, and keys for these taxa.

What is a genus-interpreting structural diversity among species of urothripine Phlaeothripinae (Thysanoptera).

Variation within and between species is discussed in several obvious character states, including the number of visible antennal segments, prolongation of the anterior margin of the head, metaepimeral setae, and anal setae. As a result, Bebelothrips and Conocephalothrips are considered new synonyms of Amphibolothrips, and Baenothrips a new synonym of Stephanothrips. The revised generic classification suggests that urothripines are largely absent from the Neotropics, with four recorded species all likely to be introductions from the Old World.