Nymphal Characters Research Articles

Taxonomic review of the Oriental genus Polyplocia Lestage, 1921 (Ephemeroptera, Euthyplociidae), with two new records for Thailand.

Previously, the euthyplociid mayfly from Thailand was reported as Polyplocia spp. without designation to any nominal species. In this study, the genus Polyplocia Lestage, 1921 in Thailand was reviewed. Two species are recognized: Polyplociaorientalis Nguyen & Bae, 2003 and P.nebulosa Gonçalves & Peters, 2016. This is the first report of P.nebulosa in Continental Asia. Cytochrome c oxidase subunit I (COI) data and illustrations based on nymphal characters were used to confirm two different species in Thailand. Additional morphological characteristics of the nymph and eggs of the two species from Thailand are also shown in detail. The taxonomic status of Polyplocia in the Oriental region is reviewed. Keys to known nymphal and imaginal stages are provided and the distribution of Polyplocia in the Oriental region is discussed.

Functional Analysis of a Juvenile Hormone Inducible Transcription Factor, Krüppel homolog 1, in the Bean Bug, Riptortus pedestris.

Juvenile hormone (JH) has two major functions in insects, i.e., suppression of metamorphosis in the larval or nymphal stage and promotion of reproduction in the adult stage. Krüppel homolog 1 (Kr-h1), a C2H2 zinc-finger type transcription factor, is reported to act downstream of the JH receptor complex. In the present study, the function of Kr-h1 was examined in adults and nymphs of Riptortus pedestris by RNA interference (RNAi). After injection of adults with dsRNA of Kr-h1, the expression level of Kr-h1 was significantly decreased in the abdomen. Kr-h1 dsRNA-injection resulted in a lower proportion of individuals with developed ovaries, but the difference was not statistically significant. The transcript levels of cyanoprotein-α and vitellogenin-1, which are JH-inducible genes encoding yolk proteins, were not affected in the abdomen by Kr-h1 knockdown. Kr-h1 dsRNA-injection was effective for suppression of Kr-h1 expression in nymphs. Some Kr-h1 dsRNA-injected fifth (final) instar nymphs had morphological defects in the wing bud. Moreover, they had several adult morphological features, including ocelli in the head, connexivum in the abdomen, coloring of the dorsal abdomen, and genitals. The nymphs possessing adult features did not emerge as adults during 1 month. These results demonstrated that Kr-h1 is necessary for maintaining nymphal characters in R. pedestris. The function of Kr-h1 in ovarian development remains unclear in R. pedestris.

Two new species of Alainites (Ephemeroptera, Baetidae) from the Mediterranean biodiversity hotspot.

The mayfly genus Alainites Waltz & McCafferty, 1994 encompassed 20 species and was represented across the West Palaearctic region by six species. Based on morphological (nymphal characters) and molecular (mitochondrial COI sequences) evidence, two new species are described: A.bengunn sp. nov. from Sardinia and A.gasithi sp. nov. from Israel. Both species are confined to narrow distribution ranges, in line with most of their congeners from the region. The key nymphal traits are discussed and identified to distinguish species in the group.

A new mayfly species of Sparsorythus Sroka & Soldán, 2008 (Insecta: Ephemeroptera: Tricorythidae) from the Western Ghats, Kerala, India

A new mayfly species Sparsorythus chitturensis sp. nov. is described from Kerala, southern India based on nymphal characters. The new species is differentiated from all other known Oriental species by the following combination of characters: (i) segment III of labial palp blunt at apex; (ii) hypopharyngeal lingua is not divided by a rill; and (iii) wing pads reaching the middle of abdominal segment II of final instar larvae. Distribution and ecological notes were provided for the described species.

Nymphal description of Tricorythodes zagaia n. comb. and Tricorythodes pemonensis n. comb. (Ephemeroptera: Leptohyphidae) and first records from Colombia.

The nymphal stages of Tricorythodes pemonensis n. comb. and T. zagaia n.comb. are firstly described. The nymphal characters as well as the characteristic swelling at the base of second forceps segment in male imago justify moving them from Macunahyphes to Tricorythodes. Additionally, other three species described in Macunahyphes are also transferred to Tricorythodes: Tricorythodes araca (Souto Salles) new comb., Tricorythodes eduardoi (Almeida Mariano) new comb., and Tricorythodes incognitus (Molineri et al.) new comb. Macunahyphes australis is the only species that remains in the genus.

Morphometry and chaetotaxy of the nymphs of Ectemnostega (Ectemnostegella) quechua (Bachmann 1961) (Insecta: Hemiptera: Heteroptera: Corixidae)

The egg and the five nymphal instars of Ectemnostega quechua are described and illustrated for the first time. The eggs of Ectemnostega have a short stalk, and the shape, size and chorionic structure differ among groups of species. The nymphal characters most useful in identifying instars I–V of Ectemnostega are: body length; number of rostrum sulcations; number of setae on inner surface of protibiotarsus; spines and setae, and spines on posteroventral surface of mesofemur and mesotibia, respectively; setae on posterodorsal surface of mesotibia and mesotarsus; spines and setae on anteroventral surface and setae on posterior surface of metatibia; swimming hairs on anteroventral and posterodorsal surfaces of metatarsus; and the grade of development of wing pads. The nymphs of E. quechua can be easily distinguished from other species of Ectemnostega by the number of spines and setae on the posteroventral surface of mesofemur.

Description of the nymphs of Ectemnostega (Ectemnostegella) stridulata (Hungerford 1948) (Hemiptera: Heteroptera: Corixidae)

The egg and the five nymphal instars of Ectemnostega (Ectemnostegella) stridulata are described and illustrated for the first time, with emphasis on the morphometry and chaetotaxy of selected structures. Comparison with the eggs of E. (Ectemnostegella) montana and E. (Ectemnostegella) peruana, and the nymphs of E. montana and E. (Ectemnostega) quadrata, are included. The egg of E. stridulata has a very short stalk like those of E. montana and E. peruana, and the three species differ in the chorionic structure. The nymphs of Ectemnostega share the presence of one dorsal abdominal scent gland on each of the segments IV–V. The number of spines on the profemur on the ventral and posteroventral surfaces distinguishes the nymphs of the subgenus Ectemnostega from the those of the subgenus Ectemnostegella. The nymphal characters most useful in identifying instars I–V of Ectemnostega are: the body length, the number of spines on the posteroventral surface of the mesofemur, setae on the posterodorsal surface and spines on the posteroventral surface of the mesotibia, setae on the posterodorsal surface of the mesotarsus, and the grade of development of the wing pads. The nymphal characters most useful in identifying species of Ectemnostega are: the number of spines on the posteroventral surface of the mesofemur, spines on the anterodorsal surface of the metatibia, and spines and swimming hairs on the anteroventral and posterodorsal surfaces of the metatarsus.

Description of the nymphs of Tenagobia (Incertagobia) incerta Lundblad 1929 and Tenagobia (Schadeogobia) schadei Lundblad 1929 (Hemiptera: Heteroptera: Micronectidae), with emphasis on morphometry and chaetotaxy

The three last nymphs of Tenagobia (Incertagobia) incerta and the egg and the third and fifth nymphs of T. (Schadeogobia) schadei are described and illustrated for the first time, with emphasis on the morphometry and chaetotaxy of selected structures. Comparisons with the nymphs of T. (Fuscagobia) fuscata and the eggs of T. fuscata, T. (Tenagobia) pulchra, and T. (Fuscagobia) selecta are included. The egg of T. schadei has a very long stalk like those of T. selecta and T. fuscata, and it differs from the ones of T. pulchra and T. incerta, which have a short stalk. The nymphs of Tenagobia share the presence of 1 dorsal abdominal scent gland on each of the segments III–V, and the absence of spines on the metafemur, except those on postero-apical surface which are present. The nymphal characters most useful in identifying nymphs III-V of Tenagobia are: the body length, the head width, the grade of development of the wing pads, the number of setae on the inner surface of the protibiotarsus, spines on the anteroventral and posteroventral surfaces of the mesofemur, lanceolate setae on the anterior surface of the metatibia, and spines on the metatibial comb. The nymphal characters most useful in identifying species of Tenagobia are the head width, the number of setae on the dorsal row of the protibiotarsus, and spines on the anterior surface of the mesotibia.

The endocrine regulation of insect metamorphosis and the emerging role of microRNAs

Event Abstract Back to Event The endocrine regulation of insect metamorphosis and the emerging role of microRNAs Xavier Belles1* 1 Universitat Pompeu Fabra, Institute of Evolutionary Biology, Spain Insect are classified into two groups according to the metamorphosis mode: the hemimetabolans, which hatch as nymphs with a morphology similar to that of the adult and grow progressively until the adult stage; and the holometabolans, which hatch as a larva with a morphology different from that of the adult, then grow through successive molts until the last larval instar, then to the pupae and to the adult. In the 1930 decade, the experiments of Vincent B. Wigglesworth already showed that the endocrine regulation of insect metamorphosis is based on molting hormones, which induce the successive molts, and juvenile hormones which maintain the juvenile character of them. Later, a number of transcription factors have been reported as mediators of the above hormones, as well as a number of target genes that codify for proteins giving the characteristic shape and behaviour of a juvenile or an adult stage. Most of the information available, however, refers to the most derived holometabolan species, especially to the fruitfly Drosophila melanogaster, whereas data on the less modified hemimetabolan species are scarce. Working on the hemimetabolan Blattella germanica (the German cockroach), we have recently found that microRNAs, which are RNAs of ca. 22 nucleotides that play a generally repressing action on mRNA stability and translation, have a key role in metamorphosis. With RNA interference (RNAi), we silenced the expression of dicer-1, a ribonuclease that mediates the maturation of microRNAs. When dicer-1 was silenced in the last nymphal instar, the production of microRNAs was impaired and the cockroaches, instead of molting to the adult stage as controls did, they transformed into gigantic supernumerary nymphs (Gomez-Orte & Belles, PNAS 106: 21678-21682, 2009). These results demonstrated that microRNAs are essential in insect metamorphosis, at least in hemimetabolans. The hypothesis emerging is that particular microRNAs would repress the expression of genes giving nymphal characters in the molt to adult. To test it, we are now working on a number of microRNAs that could be candidates to play such a role, studying their pattern of expression and the influence of the molting hormone and the juvenile hormone on their abundance. Experiments of silencing of those microRNA that might play a role in metamorphosis, studies on the effect of them on predicted targets, and building of networks representing the interaction microRNA/targets in pre-metamorphic and metamorphic stages are also included in our project. In the end, we hope that the results obtained will illuminate the endocrine mechanisms that allowed the evolutionary transition from the ancestral hemimetaboly to the derived holometaboly. Keywords: comparative endocrinology Conference: 25th Conference of the European Comparative Endocrinologists, Pécs, Hungary, 31 Aug - 4 Sep, 2010. Presentation Type: Conference Presentation Topic: Comparative endocrinology Citation: Belles X (2010). The endocrine regulation of insect metamorphosis and the emerging role of microRNAs. Front. Endocrinol. Conference Abstract: 25th Conference of the European Comparative Endocrinologists. doi: 10.3389/conf.fendo.2010.01.00017 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Aug 2010; Published Online: 29 Aug 2010. * Correspondence: Dr. Xavier Belles, Universitat Pompeu Fabra, Institute of Evolutionary Biology, Barcelona, Spain, xavier.belles@ibe.upf-csic.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Xavier Belles Google Xavier Belles Google Scholar Xavier Belles PubMed Xavier Belles Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Towards a new paradigm in mayfly phylogeny (Ephemeroptera): combined analysis of morphological and molecular data

Abstract.This study represents the first formal morphological and combined (morphological and molecular) phylogenetic analyses of the order Ephemeroptera. Taxonomic sampling comprised 112 species in 107 genera, including 42 recognized families (all major lineages of Ephemeroptera). Morphological data consisted of 101 morphological characters. Molecular data were acquired from DNA sequences of the 12S, 16S, 18S, 28S and H3 genes. The Asian genusSiphluriscus(Siphluriscidae) was supported as sister to all other mayflies. The lineages Carapacea, Furcatergalia, Fossoriae, Pannota, Caenoidea and Ephemerelloidea were supported as monophyletic, as were many of the families. However, some recognized families (for example, Ameletopsidae and Coloburiscidae) and major lineages (such as Setisura, Pisciforma and Ephemeroidea among others) were not supported as monophyletic, mainly due to convergences within nymphal characters. Clade robustness was evaluated by multiple methods and approaches.

A new species of symbiocloeon (Ephemeroptera: Baetidae) associated with a freshwater mussel from India

A new species of Symbiocloeon, residing in the gill lamella of an ancient gondwanian species of freshwater mussel, Pseudomulleria dalyi (Unionoida: Etheriidae) is described from nymphs collected from the Tunga river of Western Ghats, Shimoga district, Karnataka, India. The diagnostic nymphal characters of Symbiocloeon madhyasthai, sp. nov., are given and differentiated from Symbiocloeon heardi Muller-Liebenau.

The nymphs of two rare western stonefly (Plecoptera) species, representing little-known genera

Abstract The nymphs of two uncommon stonefly species Calileuctra dobryi Shepard & Baumann and Haploperla chilnualna (Ricker) are described and illustrated from correlated and reared specimens collected from California streams from 2004 to 2006. The diagnostic characters of these nymphs of both species affirm the nymphal generic characters for Calileuctra (Leuctridae) and Haploperla (Chloroperlidae) proposed by Stewart & Stark (2002). Absence of Calileuctra dobryi in interrupted and intermittent streams in drought years suggest that it is capable of having extended egg diapause and flexible univoltine to semivoltine life cycles similar to some species of Zealeuctra.

A New Subgenus of <I>Rhithrogena</I> from China, with Description of a New Species (Ephemeroptera: Heptageniidae)

Abstract Imagos of Rhithrogena (Tumungula) unica subgen. n., sp. n. from Yunnan and Guizhou provinces, China, have a series of unique characteristics. Male imagos have a hypertrophied foreclaw and a first tarsal segment ≈1.5 times the length of the second. The male styliger plate has two sharp projections, and the penis lobes are divergent without titillators but with spiny median lobes. Nymphal characters are those of the genus as presently defined: three caudal filaments and gills modified to form an adhesive disc.

Nymphs of Some Species of the Tribes Drabescini and Paraboloponini with a Proposed Synonymy of Paraboloponini with Drabescini (Hemiptera: Cicadellidae: Deltocephalinae)

The last instar nymphs of some species from the genera Drabescus, Welmaya, Athysanopsis, Kutara, and Dryadomorpha are described. Based on mainly nymphal characters the tribe Paraboloponini is considered a junior synonym of Drabescini. The nymphal characters uniting these groups are as follows: head with dorsal and ventral longitudinal carinae, antennae long; the entire body not rarely covered with numerous setae, abdomen with 2–8 longitudinal rows of setae, in some cases on tubercles; pygofer with pair of long apical appendages widely separated at base. Drabescini is considered a tribe of the subfamily Deltocephalinae.

THE NYMPH OF SIPHLURISCUS CHINENSIS AND ADDITIONAL IMAGINAL DESCRIPTION: A LIVING MAYFLY WITH JURASSIC ORIGINS (SIPHLURISCIDAE NEW FAMILY: EPHEMEROPTERA)

Abstract The nymph, female imago and egg of Siphluriscus chinensis Ulmer are described and figured in detail for the first time based on associated nymphs and imagos from China. Additional characters of the male imago are described. Based upon imaginal and nymphal characters, Siphluriscidae fam. n. is established in the Siphlonuroidea for Siphluriscus and, provisionally, the Jurassic genus Stackelbergisca Tshernova. Siphluriscus ? davidi Navas, known from one male subimago, is transferred to Siphlonurus davidi comb. n. The family Siphluriscidae is distinguished from all other families of Siphlonuroidea by the presence of coxal gills on the fore and middle legs in all stages and in the nymph by the presence of a basal, moveable, dactyl-like appendage on each claw, and labial and maxillary gills. Characters of the nymphal mouthparts, particularly the mandibles and maxillae, suggest that Siphluriscidae is a sister-group of the family Nesameletidae. However, the majority of character states are considered ple...

SYNONYMY AND VALID NAME OF THE FAMILIES VIETNAMELLIDAE AND AUSTREMERELLIDAE (EPHEMEROPTERA: EPHEMERELLOIDEA)

Tshernova (1972) established the genus Vietnamella for a new species of Asian Ephemerellidae, Vietnamella thani. Allen (1980), with little discussion, placed Vietnamella as a subgenus of Cincticostella Allen, 1971, in the tribe Ephemerellini. Later, Allen (1984), with somewhat more discussion of the nymphal characters, in particular the nymphal gills, admitted that the placement of Vietnamella as a subgenus of Cincticostella had been incorrect. He established a new subtribe of the Ephemerellini, Vietnamellae, for Vietnamella. Edmunds and Murvosh (1995) transferred the genus Vietnamella to the related subfamily Teloganodinae and retained the tribe name Vietnamellini for it. McCafferty and Wang (1997) presented evidence that Vietnamella was closely related toAustremerella Riek, 1963, and, apparently overlooking the existence of the subfamily name Vietnamellinae, established a new subfamily, Austremerellinae, in the family Teloganodidae for the two genera. Then, McCafferty and Wang (2000) proceeded to raise the taxon to a family, which they called Austremerellidae. According to the International Code of Zoological Nomenclature (ICZN 1999: Article 36.1) establishment of Vietnamellae (Allen 1984) had the effect of also establishing names for all other ranks in the family group (coordinate taxa: e.g., family, subfamily, tribe). This means that the name Vietnamellidae became available and valid at that time. In determining the valid name of a zoological taxon, the Principle of Priority applies (ICZN 1999: Article 23). It states that The valid name of a taxon is the oldest available name applied to it .. Although the Code does make exceptions for family names in prevailing usage (IC2N 1999: Article 35.5), Article 23.9.1 describes prevailing usage to require, among other things, that the senior synonym has not been used as a valid name after 1899. This is clearly not the case here. Vietnamellae (and its coordinate taxa) was established in 1984 and was an available and valid name at the time Austremerellidae was established. Therefore the valid name for this family of Ephemerelloidea is Vietnamellidae Allen, and Austremerellidae McCafferty and Wang is a junior synonym.

Ephemeroptera egg chorion characters: a test of their importance in assessing phylogenetic relationships.

The egg chorion ultrastructures of the Hermanella-Traverella (Insecta: Ephemeroptera) species complex were studied from a comparative point of view and used for the first time in a cladistic analysis. Egg characters, along with other nymphal and adult morphological characters, were used to assess the phylogenetic relationships of the species complex. In order to test the value of egg characters, analyses were performed on three matrices: 1) egg characters alone, 2) adult and nymphal characters, and 3) adult, nymphal, and egg characters. The computer program Pee-Wee was used to carry out the analysis. The cladistic analysis confirmed the value and potential of egg chorionic characters in assessing the phylogenetic relationships among ephemeropteran species. Egg characters, when added to the nymphal and adult character matrix, provided extra support to the monophyletic nature of the Hermanella-Traverella complex. Previously weakly defined clades were also resolved based on the new evidence. In the species studied the egg chorionic structures as well as their shape did not change after oviposition or water immersion, remaining constant through the different maturation stages of each species (mature nymph, subimago, and imago). For this reason, the eggs are a valuable source of information to unambiguously identify and associate a nymph to its correspondent adult stage when rearing is not possible.

Systematics, cladistics and biogeography of the American genusFarrodes(Ephemeroptera: Leptophlebiidae: Atalophlebiinae)

Cladistic and biogeographic analyses of the genusFarrodesare presented. Two species groups are delineated withinFarrodesF. caribbianusandF. bimaculatus. Three species formerly placed in other genera—Thraulus caribbianusTraver,Thraulus roundsiTraver andHomothraulus maculatus(Needham & Murphy)—are transferred toFarrodes. The species of theF. caribbianusspecies group are revised. Three new species are describedF. savageifrom Venezuela,F. mayaandF. mexicanusfrom Mexico. Keys to separate the two species groups ofFarrodesand the species of theF. caribbianusspecies group are provided. Successive cladistic analyses were carried out on both adult and nymphal characters using Hennig86 and CLADOS. The matrix was composed of all available data (nymphal characters were missing for some species), from nymphal and adult stages separately and on taxa represented by both adult and nymphal characters. Species of the generaSimothraulopsisandHomothraulus(components of theFarrodeslineage) were included in the analyses, andEcuaphlebiawas used as the outgroup. Results of the four analyses are compatible. The historical biogeography ofFarrodes, with a distribution from northern Argentina to southern Texas, is analysed using the program COMPONENT. Areas of endemism are established, and some of their relationships compared with those of other groups available in the literature.

Systematics, cladistics and biogeography of the American genus Farrodes (Ephemeroptera: Leptophlebiidae: Atalophlebiinae)

Abstract Cladistic and biogeographic analyses of the genus Farrodes are presented. Two species groups are delineated within Farrodes F. caribbianus and F. bimaculatus . Three species formerly placed in other genera— Thraulus caribbianus Traver, Thraulus roundsi Traver and Homothraulus maculatus (Needham & Murphy)—are transferred to Farrodes . The species of the F. caribbianus species group are revised. Three new species are described F. savagei from Venezuela, F. maya and F. mexicanus from Mexico. Keys to separate the two species groups of Farrodes and the species of the F. caribbianus species group are provided. Successive cladistic analyses were carried out on both adult and nymphal characters using Hennig86 and CLADOS. The matrix was composed of all available data (nymphal characters were missing for some species), from nymphal and adult stages separately and on taxa represented by both adult and nymphal characters. Species of the genera Simothraulopsis and Homothraulus (components of the Farrodes lineage) were included in the analyses, and Ecuaphlebia was used as the outgroup. Results of the four analyses are compatible. The historical biogeography of Farrodes , with a distribution from northern Argentina to southern Texas, is analysed using the program COMPONENT. Areas of endemism are established, and some of their relationships compared with those of other groups available in the literature.

Gonserellus: A new genus of Leptophlebiidae (Ephemeroptera) from Southern South America

Gonserellus atopus from Chile, a new genus and species, is described based on the mature nymph. The nymph of Gonserellus is distinguished from that of other leptophlebiid genera by having a well‐developed galea‐Iacinial tusk on the maxilla and prominent bipectinate spines on the tibiae. Gonserellus appears to be a member of the Nousia lineage based on a number of shared derived nymphal characters.