Male Morphology Research Articles

Evolution of the male palp morphology of the orb-weaver hunting spider Chorizopes (Araneae : Araneidae) revisited on a new phylogeny of Araneidae, and description of a third species from Madagascar

The genus Chorizopes (Araneae, Araneidae) includes over two dozen species of webless araneids found mainly in the Indomalayan region. They are characterised by a distinctive bulbous carapace and a specialised foraging behaviour: preying on other orb-weavers. Chorizopes casictones, sp. nov. (Araneae, Araneidae) is described based on specimens collected in northern Madagascar. This species represents the third member of Chorizopes known from the island. We conducted a total-evidence analysis based on morphology, behaviour and nucleotide sequence data, including this taxon for the first time. The palpal morphology of the male of Chorizopes is illustrated in detail. We discuss the palpal homologies and the evolution of araneid palpal sclerites based on the newly inferred family phylogenetic tree.

Defects in mating behavior and tail morphology are the primary cause of sterility in Caenorhabditiselegans males at high temperature.

Reproduction is a fundamental imperative of all forms of life. For all the advantages sexual reproduction confers, it has a deeply conserved flaw: it is temperature sensitive. As temperatures rise, fertility decreases. Across species, male fertility is particularly sensitive to elevated temperature. Previously, we have shown in the model nematode Caenorhabditiselegans that all males are fertile at 20°C, but almost all males have lost fertility at 27°C. Male fertility is dependent on the production of functional sperm, successful mating and transfer of sperm, and successful fertilization post-mating. To determine how male fertility is impacted by elevated temperature, we analyzed these aspects of male reproduction at 27°C in three wild-type strains of C. elegans: JU1171, LKC34 and N2. We found no effect of elevated temperature on the number of immature non-motile spermatids formed. There was only a weak effect of elevated temperature on sperm activation. In stark contrast, there was a strong effect of elevated temperature on male mating behavior, male tail morphology and sperm transfer such that males very rarely completed mating successfully when exposed to 27°C. Therefore, we propose a model where elevated temperature reduces male fertility as a result of the negative impacts of temperature on the somatic tissues necessary for mating. Loss of successful mating at elevated temperature overrides any effects that temperature may have on the germline or sperm cells.

A new case of West-East differentiation of the freshwater fauna in Northern Eurasia: the Pleuroxus trigonellus species group (Crustacea: Cladocera: Chydoridae).

Cladocerans (Crustacea: Branchiopoda) of Northern Eurasia traditionally belong to the most intensively studied groups of freshwater microcrustaceans. However, despite a significant progress in our knowledge of different aspects on their biology, some intriguing questions remain unresolved. The hypothesis of cladoceran faunas differentiation between the western and eastern parts of Northern Eurasia agrees with the continental endemism concept. But to date few cladoceran species groups have been investigated through the whole North Eurasian range. Our current work contributes to the confirmation of this hypothesis through a revision of the poorly studied Pleuroxus trigonellus species group. Based on material from Europe, we redescibed morphology of Pleuroxus trigonellus (O.F. Müller, 1776) s.str. and found that its distribution range is potentially restricted to the western portion of Northern Eurasia. At the same time, morphologically similar populations from the eastern portion of Eurasia belong to a new species, Pleuroxus yakutensis sp. nov. These two species are basically similar in general morphology of parthenogenetic and gamogenetic females, but have clear differences in the male morphology. Additionally we offer an identification key for discrimination of the P. trigonellus group from P. uncinatus (Baird, 1850) according to morphological features of the males.

Morpho-regulation in diverse chicken feather formation: Integrating branching modules and sex hormone-dependent morpho-regulatory modules.

Many animals can change the size, shape, texture and color of their regenerated coats in response to different ages, sexes, or seasonal environmental changes. Here, we propose that the feather core branching morphogenesis module can be regulated by sex hormones or other environmental factors to change feather forms, textures or colors, thus generating a large spectrum of complexity for adaptation. We use sexual dimorphisms of the chicken to explore the role of hormones. A long-standing question is whether the sex-dependent feather morphologies are autonomously controlled by the male or female cell types, or extrinsically controlled and reversible. We have recently identified core feather branching molecular modules which control the anterior-posterior (bone morphogenetic orotein [BMP], Wnt gradient), medio-lateral (Retinoic signaling, Gremlin), and proximo-distal (Sprouty, BMP) patterning of feathers. We hypothesize that morpho-regulation, through quantitative modulation of existing parameters, can act on core branching modules to topologically tune the dimension of each parameter during morphogenesis and regeneration. Here, we explore the involvement of hormones in generating sexual dimorphisms using exogenously delivered hormones. Our strategy is to mimic male androgen levels by applying exogenous dihydrotestosterone and aromatase inhibitors to adult females and to mimic female estradiol levels by injecting exogenous estradiol to adult males. We also examine differentially expressed genes in the feathers of wildtype male and female chickens to identify potential downstream modifiers of feather morphogenesis. The data show male and female feather morphology and their color patterns can be modified extrinsically through molting and resetting the stem cell niche during regeneration.

Revision of Bruchomyiinae (Diptera, Psychodidae) of the Oriental Region, with description of a new genus and species and discussion of putative male/female antagonistic coevolution

We revise the Oriental species of Bruchomyiinae based on type and additional material, with first descriptions of the genus Alexanderia Wagner & Kvifte, gen. nov. and A. thailandensis Wagner, Rulik & Polseela, sp.nov. The genus further comprises Nemapalpus orientalis Edwards, 1928 (type species), Nemopalpus vietnamensis Quate, 1962 and Nemapalpus unicolor Edwards, 1928. Alexanderia thailandensis is described using morphology of males and females and DNA barcodes, whereas A. orientalis Edwards, 1928 comb.nov., A. unicolor Edwards 1928 comb.nov., and A. vietnamensis Quate 1962 comb. nov. are redescribed. The male and female internal genitalia in the genus are discussed in the context of sexual selection, and we suggest that the spermathecal ducts of the female and the basiphallic musculature of the male may be shaped by a male/female coevolutionary arms race.

Two\u2019s company, three\u2019s a crowd: co-occurring pollinators and parasite species in Breynia oblongifolia (Phyllanthaceae)

BackgroundObligate pollination mutualisms (OPMs) are specialized interactions in which female pollinators transport pollen between the male and female flowers of a single plant species and then lay eggs into those same flowers. The pollinator offspring hatch and feed upon some or all of the developing ovules pollinated by their mothers. Strong trait matching between plants and their pollinators in OPMs is expected to result in reciprocal partner specificity i.e., a single pollinator species using a single plant species and vice versa, and strict co-speciation. These issues have been studied extensively in figs and fig wasps, but little in the more recently discovered co-diversification of Epicephala moths and their Phyllanthaceae hosts. OPMs involving Epicephala moths are believed occur in approximately 500 species of Phyllanthaceae, making it the second largest OPM group after the Ficus radiation (> 750 species). In this study, we used a mixture of DNA barcoding, genital morphology and behavioral observations to determine the number of Epicephala moth species inhabiting the fruits of Breynia oblongifolia, their geographic distribution, pollinating behavior and phylogenetic relationships.ResultsWe found that B. oblongifolia hosts two species of pollinator that co-occurred at all study sites, violating the assumption of reciprocal specificity. Male and female genital morphologies both differed considerably between the two moth species. In particular, females differed in the shape of their ovipositors, eggs and oviposition sites. Phylogenetic analyses indicated that the two Epicephala spp. on B. oblongifolia likely co-exist due to a host switch. In addition, we discovered that Breynia fruits are also often inhabited by a third moth, an undescribed species of Herpystis, which is a non-pollinating seed parasite.ConclusionsOur study reveals new complexity in interactions between Phyllantheae and Epicephala pollinators and highlights that host switching, co-speciation and non-pollinating seed parasites can shape species interactions in OPMs. Our finding that co-occurring Epicephala species have contrasting oviposition modes parallels other studies and suggests that such traits are important in Epicephala species coexistence.

Redefinition and taxonomic revision of the “buqueti” species-group, Dichotomius Hope, 1838 (Coleoptera: Scarabaeidae: Scarabaeinae)

On the basis of external morphology and genitalia of males, as well as a comparison between different species belonging to other groups of Dichotomius, we propose a redefinition of the “buqueti” species group separated by Luederwaldt (1929). Six species are excluded from this group and transferred to other groups: D. ribeiroi (Pereira, 1954) in the “cotopaxi” group; D. camposeabrai Martínez, 1974 in the “bitiensis” group; D. reclinatus (Felsche, 1901), D. horridus (Felsche, 1911), D. quadrinodosus (Felsche, 1901) and D. nimuendaju (Luederwaldt, 1925) (revalidated species) forming the newly defined “reclinatus” group. The other species kept in the “buqueti” group include D. buqueti (Lucas, 1857) from Brazil (lectotype here designated), D. haroldi (Waterhouse, 1891) from Argentina and D. nutans (Harold, 1867) from Brazil, Argentina and Uruguay. The taxonomic revision of the “buqueti” group are presented, including a history of the included species, a determination key, illustrations of the structures of external morphology, male genitalia and sclerites of the internal sac, and a distribution map.

Divergence in female damselfly sensory structures is consistent with a species recognition function but shows no evidence of reproductive character displacement.

Males and females transmit and receive signals prior to mating that convey information such as sex, species identity, or individual condition. In some animals, tactile signals relayed during physical contact between males and females before and during mating appear to be important for mate choice or reproductive isolation. This is common among odonates, when a male grasps a female's thorax with his terminal appendages prior to copulation, and the female subsequently controls whether copulation occurs by bending her abdomen to complete intromission. It has been hypothesized that mechanosensory sensilla on the female thoracic plates mediate mating decisions, but is has been difficult to test this idea. Here, we use North American damselflies in the genus Enallagma (Odonata: Coenagrionidae) to test the hypothesis that variation in female sensilla traits is important for species recognition. Enallagma anna and E. carunculatum hybridize in nature, but experience strong reproductive isolation as a consequence of divergence in male terminal appendage morphology. We quantified several mechanosensory sensilla phenotypes on the female thorax among multiple populations of both species and compared divergence in these traits in sympatry versus allopatry. Although these species differed in features of sensilla distribution within the thoracic plates, we found no strong evidence of reproductive character displacement among the sensilla traits we measured in regions of sympatry. Our results suggest that species‐specific placement of female mechanoreceptors may be sufficient for species recognition, although other female sensory phenotypes might have diverged in sympatry to reduce interspecific hybridization.

The first detection of Ashworthius sidemi (Nematoda, Trichostrongylidae) in roe deer (Capreolus capreolus) in Russia.

Ashworthius sidemi is a blood-sucking nematode, which has spread out among wild ruminants in several European countries during last decades. The nematode has recently been detected in cattle as well. The distribution of A. sidemi in Russia has not been sufficiently clarified yet. In European part of Russia A. sidemi was formerly registered in sika deer (Cervus nippon) and maral (Cervus elaphus sibiricus) introduced from Asia, and also in aboriginal elks (Alces alces). Taking into consideration the presence of other species of ruminants susceptible to A. sidemi in European Russia, it is necessary to control the spread of this parasite. The specimens of males and females of A. sidemi were found during the autopsies of three naturally infected roe deer (Capreolus capreolus) from Voronezh and Tver regions (European Russia). The species affiliation of the discovered nematodes was determined according to morphological features and confirmed using molecular techniques. The intensity of infection with A. sidemi in two roe deer from Voronezh was 11 and 63 nematodes, and it was 17 nematodes in roe deer from Tver. All of the discovered specimens of A. sidemi were referred to juvenile forms based on features of male bursa morphology and weak development of female reproductive system. In Russia, A. sidemi has not previously been detected in C. capreolus and the present report constitutes the first record of the parasite occurrence in this species of ruminant.

Description of three new species of Aposphragisma Thoma, 2014 (Araneae: Oonopidae) from Sumatra, Indonesia.

Three species from the family Oonopidae are newly described from leaf litter habitats in Sumatra, Indonesia based on male and female morphology. All three species belong to the genus Aposphragisma Thoma, 2014: Aposphragismaglobosumsp. n., Aposphragismajambisp. n., and Aposphragismasumatrasp. n.

Inferring species boundaries using acoustic and morphological data in the ground cricket genus Gymnogryllus (Orthoptera: Grylloidea: Gryllinae)

An important function of song production by male crickets is to attract conspecific females. These sound signals can be used to infer species boundaries as they can provide indirect evidence for reproductive isolation. However, many studies of orthopteran diversity in South-east Asia are based mainly on morphology and only occasionally acoustics. As such, there is a lack of information on how acoustic data can be congruent with morphological data when used to delineate species. Crickets of the genus Gymnogryllus (Grylloidea, Gryllidae), are such an example. Gymnogryllus are relatively speciose, but their calling songs have not been studied. We collected specimens and calling songs of five Gymnogryllus species from South-east Asia. The acoustic parameters of the calls, along with male tegminal venation and morphology genitalia, were compared. All data types showed congruency in distinguishing G. sylvestris and G. leucostictus from each other and from the other species. Inferring species boundaries for G. angustus, G. malayanus, and G. unexpectus using acoustics and tegminal morphometry proves to be more challenging. While acoustics, tegminal morphometry, and genital morphology are likely to be useful for inferring species of Gymnogryllus from different species groups, greater coverage of taxa is needed to resolve taxonomy of closely related Gymnogryllus.

Consistent seasonal polyphenism in male genitalia of threeLeptideabutterfly species (Lepidoptera: Pieridae)

Insect genitalia are important for species identification and taxonomy and are key traits for the evolution of reproductive isolation through their 'lock-And-key mechanism'. Nevertheless, few studies have evaluated intraspecific variation and the impact of seasonal environmental variation on genital morphology. We used geometric morphometric analysis to quantify male genital morphology within and among the three taxa in the Leptidea sinapis cryptic species complex (Lepidoptera: Pieridae). We focused on the potential presence of seasonal polyphenism, i.e. consistent differences among temporally separated generations. As predicted, our analysis revealed that male genitalia differed in size, shape and form (the joint effect of size and shape) among species. More surprisingly, all species harboured consistent genital variation between the spring and summer generations. The interspecific variation in genital structures could function as a mechanical reproductive barrier, although contemporary populations of these butterflies do not engage in heterospecific matings. We suggest that the smaller, but significant, genital differences among conspecific generations provide an opportunity to test empirically whether a seasonal polyphenism in genital morphology could generate raw material for the build-up of reproductive isolation at an early stage of speciation. Collectively, our results provide evidence demonstrating that insect genitalia can indeed harbour ample intraspecific variation. (Less)

Studies on crude powder and ethanolic extract of <i>Citrullus lanatus</i> seeds: phytochemical analysis, effects on haemogram and some reproductive characteristics of male albino rats

Effects of crude powder and ethanolic extract of Citrullus lanatus seeds on haemogram, spermiogram, testicular and epididymal histology of forty-eight male wistar rats were investigated following phytochemical analysis. The rats, divided into three test groups (A, B and C; n=16) were administered distilled water (Group A), ground powder (Groups B; 200mg/kg) and ethanol extract of Citrullus lanatus seed (Group C; 200mg/kg) for 28 days. Blood samples were collected from all rats after expiration of extract administration for haemogram. Subsequently, four rats from each group were sacrificed weekly post treatment for a period of four weeks for semen analysis and histology. Phytochemical analysis revealed alkaloids, flavonoids, saponins, anthraquinones, terpenoids, and cardiac glycosides. Haematological parameters were not significantly different across the groups. Mean sperm motility of the control group was significantly (p<0.05) higher compared with treatment groups (A and B) each week post treatment. Also, initial lower sperm motility recorded in week 1 and 2 post treatment in the treatment groups followed by increase at week 3 and 4 were observed. However, there were significant post treatment reductions (p<0.05) each week in sperm morphological abnormalities comparing the treatment groups with control group. Histology of the testes of Treatment groups showed numerous closely packed seminiferous tubules with normal architecture containing spermatogenic cells. The study revealed that ground powder and ethanol extract of Citrullus lanatus seeds administered at 200mg/kg have no deleterious effect on haemogram, the organs of male reproduction and sperm morphology. Hence, it may be considered safe for use in breeding animals. Keywords: Citrullus lanatus , crude powder, ethanolic, semen, haemogram

Are the monophlebid genera Drosichoides Morrison and Buchnericoccus Reyne synonyms? (Hemiptera, Coccomorpha, Monophlebidae).

The morphology of the adult male of Drosichoides ?haematoptera (Cockerell) is redescribed and illustrated and the adult female of Buchnericoccus sp. (Hemiptera: Monophlebidae) is also described and illustrated. These male and female specimens perhaps are conspecific. Genus Buchericoccus Reyne may be a junior synonym of genus Drosichoides Morrison.

Taxonomy of the Genus Bantodemus Koch, 1955 (Coleoptera: Tenebrionidae: Platynotini): Lucidus and Lethaeus Species-Groups

A new species of the genus Bantodemus is described (B. lajumaiensis sp. nov.) from the surroundings of the Lajuma Research Centre (Limpopo Province, South Africa). This discovery enforced the revision of some crucial morphological features used for species delimitation within the lucidus species-group. As a result a new identification key is provided for this species-group. Furthermore, the male morphology of Bantodemus montanus (lethaeus species-group) is described for the first time based on the material collected in the Lotheni Nature Reserve (KwaZulu-Natal, South Africa).

Selection Signatures Underlying Dramatic Male Inflorescence Transformation During Modern Hybrid Maize Breeding.

Inflorescence capacity plays a crucial role in reproductive fitness in plants, and in production of hybrid crops. Maize is a monoecious species bearing separate male and female flowers (tassel and ear, respectively). The switch from open-pollinated populations of maize to hybrid-based breeding schemes in the early 20th century was accompanied by a dramatic reduction in tassel size, and the trend has continued with modern breeding over the recent decades. The goal of this study was to identify selection signatures in genes that may underlie this dramatic transformation. Using a population of 942 diverse inbred maize accessions and a nested association mapping population comprising three 200-line biparental populations, we measured 15 tassel morphological characteristics by manual and image-based methods. Genome-wide association studies identified 242 single nucleotide polymorphisms significantly associated with measured traits. We compared 41 unselected lines from the Iowa Stiff Stalk Synthetic (BSSS) population to 21 highly selected lines developed by modern commercial breeding programs, and found that tassel size and weight were reduced significantly. We assayed genetic differences between the two groups using three selection statistics: cross population extended haplotype homozogysity, cross-population composite likelihood ratio, and fixation index. All three statistics show evidence of selection at genomic regions associated with tassel morphology relative to genome-wide null distributions. These results support the tremendous effect, both phenotypic and genotypic, that selection has had on maize male inflorescence morphology.

Mandible morphology reflects the type of male antagonism in the ant genus Cardiocondyla (Hymenoptera: Formicidae)

The ant genus Cardiocondyla is characterized by wingless, ergatoid males, which in some species replace the typical winged male. Depending on species, ergatoid males engage in lethal fighting for access to sexual females, establish territories within their nests, or are mutually tolerant. Here we investigate, whether the morphology of ergatoid males and in particular the shape of their mandibles reflect phylogeny or male behaviour. In contrast to the worker mandible, which is relatively similar in shape in the ten species examined, mandibles of ergatoid males show a great variation in size and shape not only between the two clades of Cardiocondyla but also among species belonging to Cardiocondyla clade A. This diversity appears to reflect the diverse reproductive tactics of ergatoid males of different species, with extremely long, anteriorly oriented mandibles associated with indirect killing of adult competitors, while particularly short mandibles possibly constitute an adaptation to a tactic in which ergatoid males crush the cuticle of young rivals.

Review of Poecilimon species with inflated pronotum: description of four new taxa within an acoustically diverse group.

Poecilimon Fischer (Orthoptera, Tettigoniidae) consists of about 130 species and a functional taxonomy of the genus requires arranging species into phylogenetic groups. However, this is a task that requires detailed empirical testing. This paper documents data on Poecilimon species with an inflated pronotum. The Poecilimon (Poecilimon) inflatus group is a lineage ranging along a narrow zone in the south-west corner of Anatolia and in Crete plus some other Aegean islands. By producing data of morphology and calling songs of males and responding songs of females the composition and intra-group diversity of P. inflatus group are studied. Both morphology and male calling and female responding songs, exhibited a considerable intra-group diversity. In the light of data obtained the following nomenclatural changes were made. The genus Parapoecilimon Karabağ, 1975 syn. n. is synonymised with Poecilimon Fischer and Parapoecilimon antalyaensis Karabağ, 1975 is given a new combination, Poecilimon antalyaensis (Karabağ, 1975) comb. n. Four new taxa are described in the group: (i) Poecilimon isopterus sp.n.; (ii) Poecilimon inflatus lyciae subsp. n.; (iii) Poecilimon antalyaensis myrae subsp. n., and (iv) Poecilimon antalyaensis anemurium subsp. n. The Poecilimon (P.) inflatus species group consists of the following species: (i) Poecilimon inflatus Brunner von Wattenwyl, 1891; (ii) Poecilimon martinae Heller, 2004; (iii) Poecilimon cretensis Werner, 1903; (iv) Poecilimon antalyaensis (Karabağ, 1975) comb. n.; (v) Poecilimon bilgeri Karabağ, 1953 and (vi) Poecilimon isopterus sp.n. The species group is defined by a combination of characters including the pronotum inflated in metazona and a male cerci mostly black in their apical 1/2-1/3. The male calling song has typically two types of short syllables and the females respond acoustically with very short latency times. By using combination of morphology and song data we suggest three main lineages in the group: (i) P. bilgeri, (ii) P. antalyaensis and (iii) the other four species.

Revision of the genera Cyphonethes Verhoeff, 1926 and Titanethes Schioedte, 1849 (Isopoda: Oniscoidea: Trichoniscidae) with a description of a new genus and three new taxa

A taxonomic study of two troglobite genera resulted in remarkable changes to their composition and our perception of their relationship. The genus Titanethes is treated as monotypic, with one newly described taxon, Titanethes albus matovici n. ssp. One species is transferred from Titanethes to the genus Cyphonethes, Cyphonethes biseriatus (Verhoeff, 1900) comb. nov. A species and a genus are synonymized, Microtitanethes licodrensis syn. nov. The diagnosis of the genus Cyphonethes is amended and revised using comparative morphology of adult males. A new species, Cyphonethes tajanus n. sp, is described. A close relationship between the genera Titanethes and Spelaeonethes is established. Cetinjella monasetrii n. g., n. sp, is described as a new genus and species close to the genus Cyphonethes. It is assumed to be a higropetric cave inhabitant, based on its pereopode structure, with elongated fused dactylus and unguis, and partly by its slightly modified mouthparts. Unique water uptake (for the water conducting system) by the dorsal surface of the frontal pereionite is also assumed for the species, based on the presence, distribution and orientation of specific small scales. The presence and structure of male tergal glands in the genus Tithanethes are treated as taxonomically irrelevant.

The eastern Nearctic species Rasvena terna (Frison, 1942) (Plecoptera, Chloroperlidae)

New and prior valid records of the endemic eastern Nearctic species Rasvena terna (Frison, 1942) were compiled and a dot distribution map is provided. Rasvena terna is reported from Canada (Quebec) for the first time. External reproductive morphology of adult males and adult females were studied across this species range. Scanning electron microscopy images of reproductive structures and the larval mandible are presented for the first time.