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Jeyaraney Kathirithamby - One of the best experts on this subject based on the ideXlab platform.
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a putative twisted wing parasitoid planidium insecta Strepsiptera in taimyr upper cretaceous amber
Cretaceous Research, 2017Co-Authors: Jeyaraney Kathirithamby, E E Perkovsky, Zachary H Falin, Michael S EngelAbstract:Abstract A planidium is newly recorded from Upper Cretaceous (Santonian) amber of the Taimyr Peninsula, Krasnoyarsk Territory, Siberia. This peculiar fossil is tentatively attributed to the order Strepsiptera, representing the first record of this lineage from these deposits. Planidia of a similar conicocephalate form are known from the slightly younger amber of western Canada (Campanian) as well as in the earlier (Cenomanian) amber of Myanmar, and comparisons are made with those fossils, as well as with living Strepsiptera and the beetle family Ripiphoridae (Tenebrionoidea). Given recent debate concerning the Strepsipteran attribution of these planidia, we provide some discussion about the available and expected character evidence, and tend to believe assignment to Ripiphoridae is untenable. While placement with Strepsiptera remains difficult to state conclusively, the current limited evidence still tends to prefer the Strepsipteran hypothesis.
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the first twisted wing parasitoids insecta Strepsiptera from the early eocene green river formation of colorado
Bulletin of The Peabody Museum of Natural History, 2016Co-Authors: Gwen S Antell, Jeyaraney KathirithambyAbstract:Abstract Strepsiptera is a clade of entomophagous parasitoid insects with fewer than 30 previously reported fossils. Two new species of Caenocholax (Strepsiptera: Myrmecolacidae) described here represent the first reported adult Strepsipterans preserved as organic compression fossils. Their occurrence in the Early Eocene (about 50 Ma) Green River Formation (Colorado, USA) is the northernmost New World record of Myrmecolacidae and the oldest record of Caenocholax. Caenocholax barkleyi sp. nov. and Caenocholax palusaxus sp. nov. are each known from one adult male. The aedeagus of C. barkleyi lacks a median projection and terminates in two hooks, an apomorphy of the species. Caenocholax palusaxus has distinctly intermediate wing vein density and a larger ratio of antennomere 6 to antennomere 7 than any other species of Caenocholax. The fossils reported here expand the known insect biota of the formation in taxonomic richness as well as the fossil record of Strepsiptera in space and time. Moreover, the Eocene...
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we do not select nor are we choosy reproductive biology of Strepsiptera insecta
Biological Journal of The Linnean Society, 2015Co-Authors: Jeyaraney Kathirithamby, Juan A Delgado, Francisco Collantes, Michael Hrabar, Stefan Dotterl, Donald M Windsor, Gerhard GriesAbstract:The cryptic entomophagous parasitoids in the order Strepsiptera exhibit specific adaptations to each of the 34 families that they parasitize, offering rich opportunities for the study of male–female conflict. We address the compelling question as to how the diversity of Strepsiptera (where cryptic speciation is common) arose. Studying 13 Strepsipteran families, including fossil taxa, we explore the genitalic structures of males, the free-living females of the Mengenillidia (suborder), and the endoparasitic females of the Stylopidia (suborder). Inferring from similarity between aedeagi of males either between congeners, heterogeners, or between species within the same taxonomic family, the same of which is true of the cephalothoraces of females, we predict that male–female conflict and a co-evolutionary morphological arms race between sexes is not likely to exist in most species of Strepsiptera. We then review the non-genitalic structures that play a role during sexual communication, and present details of copulatory behaviour. We conclude that Strepsiptera fall within the synchronous sensory exploitation model where short-lived males take advantage of a pre-existing sensory system involving pheromone signals emitted by females. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 00, 000–000.
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a revised key to the living and fossil families of Strepsiptera with the description of a new family cretostylopidae
Journal of the Kansas Entomological Society, 2014Co-Authors: Jeyaraney Kathirithamby, Michael S EngelAbstract:A new family, Cretostylopidae Kathirithamby and Engel, is erected to accommodate the mid-Cretaceous species Cretostylops engeli Grimaldi and Kathirithamby. Based on this as well as various other recent works pertaining to the higher classification of Strepsiptera, a revised key is provide to the living and fossil families.
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a free ride and lunch stylopization in the solitary hunting wasp ammophila fernaldi murray and a pictipennis walsh hymenoptera sphecidae by paraxenos lugubris pierce Strepsiptera
Proceedings of the Entomological Society of Washington, 2012Co-Authors: Jeyaraney Kathirithamby, Dino P Mcmahon, Gary K Lechner, Alexandra L Bryson, Spencer J JohnstonAbstract:Abstract. The intricate nest building, cleaning and provisioning habits of the solitary hunting wasps Ammophila fernaldi Murray and A. pictipennis (Walsh) (Hymenoptera: Sphecidae) are supposed to have developed in response to parasite pressure. This paper presents the first study to record the behavior of phoresy of Paraxenos lugubris Pierce (Strepsiptera: Stylopidae). Adapting to the provisioning of single-cell nests of the Ammophila sp., it is the tiny, free-living, first instar larvae of P. lugubris, that are phoretic. They are carried, not by a wasp stylopized by a female P. lugubris producing first instar larvae, but by an unstylopized foraging wasp, thereby discreetly gaining entry to a single-cell nest before it is sealed. Multiple first instar P. lugubris larvae are often taken by the host, A. fernaldi and A. pictipennis, to the single egg/ larvae in the cell, resulting in superparasitism. These observations further demonstrate that Strepsiptera have developed mechanisms for parasitizing a range o...
Rolf G Beutel - One of the best experts on this subject based on the ideXlab platform.
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Protoxenidae fam. nov. (Insecta, Strepsiptera) from Baltic amber — a ‘missing link’ in Strepsipteran phylogeny
Zoologica Scripta, 2020Co-Authors: Hans Pohl, Rolf G Beutel, Ragnar KinzelbachAbstract:A male specimen of a new Strepsipteran genus and species (Protoxenos janzeni gen. et sp. nov.) and family (Protoxenidae fam. nov.) found in Baltic amber is described and illustrated. It shows features which are apparently more plesiomorphic than in hitherto known Strepsipterans, such as laterally inserted eight-segmented antennae, very robust mandibles with a broad base, a prominent galea, a comparatively short, transverse metapostnotum, hindwings that are feebly extended in a rostrocaudal direction, and equally sclerotized abdominal tergites and sternites. Based on a cladistic analysis of 46 characters of males of 11 genera and three outgroup taxa, P. janzeni is the sister group of all other known Strepsipterans, and Mengea the sister group of Strepsiptera s.s. Eoxenos is the sister group of the remaining extant Strepsipterans and Mengenillidae is therefore paraphyletic. Newly established groundplan features of Strepsiptera will facilitate the clarification of the systematic position of the Order in future studies.
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the abdomen of a free living female of Strepsiptera and the evolution of the birth organs
Journal of Morphology, 2019Co-Authors: Daniel Troger, Rolf G Beutel, Hans PohlAbstract:: Mengenillidae is a small, basal family of Strepsiptera, mainly characterized by free-living females in contrast to the endoparasitic females of Stylopidia. Here, we describe external and internal structures of the female abdomen of Eoxenos laboulbenei (Mengenillidae). The external morphology was examined and documented using microphotography. Internal structures were reconstructed three-dimensionally using a μCT-data set. The morphologically simplified abdomen comprises 10 segments. The integument is weakly sclerotized and flexible. Spiracles are present dorsolaterally on segments I-VII. Segment VII bears the posteroventral birth opening and the small abdominal segment X carries the anus at its apex. Numerous eggs float freely in the hemolymph. The musculature of segments I-IV is composed of ventral and dorsal longitudinal muscle bundles, strongly developed paramedial dorsoventral muscles and a complex meshwork of small pleural muscles, with minimal differences between the segments. Segments V-X contain more than 50 individual muscles, even though the musculature as a whole is weakly developed. Even though it is not involved in processing food, the digestive tract is well-developed. Its postabdominal section comprises a part of the midgut and the short hindgut. The midgut fills a large part of the postabdominal lumen. The lumina of the midgut and hindgut are not connected. Five or six nodular Malpighian tubules open into the digestive tract at the border region between the midgut and hindgut. The birth organ below the midgut releases the primary larvae after hatching via the birth opening at segment VII. It is likely derived from primary female genital ducts. The presence of six additional birth organs of segments I-VI are de novo formations and a groundplan apomorphy of Stylopidia, the large Strepsipteran subgroup with endoparasitic females. The loss of the primary birth organ of segment VII is an apomorphy of Stylopiformia (Stylopidia excl. Corioxenidae).
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a needle in a haystack mesozoic origin of parasitism in Strepsiptera revealed by first definite cretaceous primary larva insecta
PeerJ, 2018Co-Authors: Hans Pohl, Jan Batelka, Jakub Prokop, Patrick Muller, Margarita Yavorskaya, Rolf G BeutelAbstract:: Twisted winged insects (Strepsiptera) are a highly specialized small order of parasitic insects. Whether parasitism developed at an early or late stage in the evolution of the group was unknown. Here we record and describe the first definite Mesozoic Strepsipteran primary larva embedded in Burmese amber (∼99 million years ago). This extends the origin of parasitism back by at least ∼50 million years, and reveals that this specialized life style has evolved in the Mesozoic or even earlier in the group. The extremely small first instar displays all diagnostic characters of Strepsipteran immatures of this stage and is nearly identical with those of Mengenillidae, one of the most "ancestral" extant Strepsipteran taxa. This demonstrates a remarkable evolutionary stasis over 100 million years. The new finding strongly weakens the case of small larvae embedded in Cretaceous amber interpreted as Strepsipteran immatures. They differ in many structural features from extant Strepsipteran primary larvae and are very likely parasitic beetle larvae.
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Traumatic insemination and female counter-adaptation in Strepsiptera (Insecta)
Scientific Reports, 2016Co-Authors: Miriam Peinert, Rolf G Beutel, Benjamin Wipfler, Gottfried Jetschke, Thomas Kleinteich, Stanislav N. Gorb, Hans PohlAbstract:In a few insect groups, males pierce the female’s integument with their penis during copulation to transfer sperm. This so-called traumatic insemination was previously confirmed for Strepsiptera but only in species with free-living females. The more derived endoparasitic groups (Stylopidia) were suggested to exhibit brood canal mating. Further, it was assumed that females mate once and that pheromone production ceases immediately thereafter. Here we examined Stylops ovinae to provide details of the mating behaviour within Stylopidia. By using μCT imaging of Stylops in copula, we observed traumatic insemination and not, as previously suggested, brood canal mating. The penis is inserted in an invagination of the female cephalothorax and perforates its cuticle. Further we show that female Stylops are polyandrous and that males detect the mating status of the females. Compared to other Strepsipterans the copulation is distinctly prolonged. This may reduce the competition between sperm of the first mating male with sperm from others. We describe a novel paragenital organ of Stylops females, the cephalothoracic invagination, which we suggest to reduce the cost of injuries. In contrast to previous interpretations we postulate that the original mode of traumatic insemination was maintained after the transition from free-living to endoparasitic Strepsipteran females.
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†Kinzelbachilla ellenbergeri – a new ancestral species, genus and family of Strepsiptera (Insecta)
Systematic Entomology, 2016Co-Authors: Hans Pohl, Rolf G BeutelAbstract:. A single male specimen of a new species (†Kinzelbachilla ellenbergeri gen. et sp.n.) of a new family of the endoparasitic Strepsiptera (†Kinzelbachillidae fam.n.) from Burmese amber is described and evaluated with respect to its systematic placement. Its features come very close to the presumptive groundplan of the order suggested in recent studies. Preserved plesiomorphic features are the following: fully sclerotized head with long coronal suture, small ommatidia not separated by chitinous bridges, absence of microtrichia between ommatidia, eight antennomeres, robust mandibles with dicondylic articulation, galea distinctly developed, free pro- and mesotrochanters, slender five-segmented tarsi without adhesive soles, and equally sclerotized abdominal tergites and sternites. An important character that is not recognizable due to damage is the shape of the metapostnotum. This structure is transverse in the groundplan of Strepsiptera and in †Protoxenos, but elongated and shield-like in all other known Strepsipterans. In a cladistic analyses of 82 characters of adult males and additional characters for females and immatures (scored as unknown for all included fossils) †Kinzelbachilla is placed as sister group of all remaining Strepsipterans except for †Protoxenos, followed by †Cretostylops and †Mengea as the third and fourth branches in the stem group, respectively. The position of †Protoxenos as first branch is suggested by three unambiguous apomorphic features of all remaining Strepsiptera, the reduced size of less than 6 mm, mandibles distinctly narrowing distad the basalmost part, and fan-shaped hindwings which are broader than they are long. The hitherto known fossil stem group Strepsipterans do not distinctly narrow the large morphological gap separating this order from its sister group, the Coleoptera. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:07554C01-DEC3-4080-A337-B1F46BC9070F.
Hans Pohl - One of the best experts on this subject based on the ideXlab platform.
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Protoxenidae fam. nov. (Insecta, Strepsiptera) from Baltic amber — a ‘missing link’ in Strepsipteran phylogeny
Zoologica Scripta, 2020Co-Authors: Hans Pohl, Rolf G Beutel, Ragnar KinzelbachAbstract:A male specimen of a new Strepsipteran genus and species (Protoxenos janzeni gen. et sp. nov.) and family (Protoxenidae fam. nov.) found in Baltic amber is described and illustrated. It shows features which are apparently more plesiomorphic than in hitherto known Strepsipterans, such as laterally inserted eight-segmented antennae, very robust mandibles with a broad base, a prominent galea, a comparatively short, transverse metapostnotum, hindwings that are feebly extended in a rostrocaudal direction, and equally sclerotized abdominal tergites and sternites. Based on a cladistic analysis of 46 characters of males of 11 genera and three outgroup taxa, P. janzeni is the sister group of all other known Strepsipterans, and Mengea the sister group of Strepsiptera s.s. Eoxenos is the sister group of the remaining extant Strepsipterans and Mengenillidae is therefore paraphyletic. Newly established groundplan features of Strepsiptera will facilitate the clarification of the systematic position of the Order in future studies.
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the abdomen of a free living female of Strepsiptera and the evolution of the birth organs
Journal of Morphology, 2019Co-Authors: Daniel Troger, Rolf G Beutel, Hans PohlAbstract:: Mengenillidae is a small, basal family of Strepsiptera, mainly characterized by free-living females in contrast to the endoparasitic females of Stylopidia. Here, we describe external and internal structures of the female abdomen of Eoxenos laboulbenei (Mengenillidae). The external morphology was examined and documented using microphotography. Internal structures were reconstructed three-dimensionally using a μCT-data set. The morphologically simplified abdomen comprises 10 segments. The integument is weakly sclerotized and flexible. Spiracles are present dorsolaterally on segments I-VII. Segment VII bears the posteroventral birth opening and the small abdominal segment X carries the anus at its apex. Numerous eggs float freely in the hemolymph. The musculature of segments I-IV is composed of ventral and dorsal longitudinal muscle bundles, strongly developed paramedial dorsoventral muscles and a complex meshwork of small pleural muscles, with minimal differences between the segments. Segments V-X contain more than 50 individual muscles, even though the musculature as a whole is weakly developed. Even though it is not involved in processing food, the digestive tract is well-developed. Its postabdominal section comprises a part of the midgut and the short hindgut. The midgut fills a large part of the postabdominal lumen. The lumina of the midgut and hindgut are not connected. Five or six nodular Malpighian tubules open into the digestive tract at the border region between the midgut and hindgut. The birth organ below the midgut releases the primary larvae after hatching via the birth opening at segment VII. It is likely derived from primary female genital ducts. The presence of six additional birth organs of segments I-VI are de novo formations and a groundplan apomorphy of Stylopidia, the large Strepsipteran subgroup with endoparasitic females. The loss of the primary birth organ of segment VII is an apomorphy of Stylopiformia (Stylopidia excl. Corioxenidae).
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a needle in a haystack mesozoic origin of parasitism in Strepsiptera revealed by first definite cretaceous primary larva insecta
PeerJ, 2018Co-Authors: Hans Pohl, Jan Batelka, Jakub Prokop, Patrick Muller, Margarita Yavorskaya, Rolf G BeutelAbstract:: Twisted winged insects (Strepsiptera) are a highly specialized small order of parasitic insects. Whether parasitism developed at an early or late stage in the evolution of the group was unknown. Here we record and describe the first definite Mesozoic Strepsipteran primary larva embedded in Burmese amber (∼99 million years ago). This extends the origin of parasitism back by at least ∼50 million years, and reveals that this specialized life style has evolved in the Mesozoic or even earlier in the group. The extremely small first instar displays all diagnostic characters of Strepsipteran immatures of this stage and is nearly identical with those of Mengenillidae, one of the most "ancestral" extant Strepsipteran taxa. This demonstrates a remarkable evolutionary stasis over 100 million years. The new finding strongly weakens the case of small larvae embedded in Cretaceous amber interpreted as Strepsipteran immatures. They differ in many structural features from extant Strepsipteran primary larvae and are very likely parasitic beetle larvae.
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Traumatic insemination and female counter-adaptation in Strepsiptera (Insecta)
Scientific Reports, 2016Co-Authors: Miriam Peinert, Rolf G Beutel, Benjamin Wipfler, Gottfried Jetschke, Thomas Kleinteich, Stanislav N. Gorb, Hans PohlAbstract:In a few insect groups, males pierce the female’s integument with their penis during copulation to transfer sperm. This so-called traumatic insemination was previously confirmed for Strepsiptera but only in species with free-living females. The more derived endoparasitic groups (Stylopidia) were suggested to exhibit brood canal mating. Further, it was assumed that females mate once and that pheromone production ceases immediately thereafter. Here we examined Stylops ovinae to provide details of the mating behaviour within Stylopidia. By using μCT imaging of Stylops in copula, we observed traumatic insemination and not, as previously suggested, brood canal mating. The penis is inserted in an invagination of the female cephalothorax and perforates its cuticle. Further we show that female Stylops are polyandrous and that males detect the mating status of the females. Compared to other Strepsipterans the copulation is distinctly prolonged. This may reduce the competition between sperm of the first mating male with sperm from others. We describe a novel paragenital organ of Stylops females, the cephalothoracic invagination, which we suggest to reduce the cost of injuries. In contrast to previous interpretations we postulate that the original mode of traumatic insemination was maintained after the transition from free-living to endoparasitic Strepsipteran females.
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†Kinzelbachilla ellenbergeri – a new ancestral species, genus and family of Strepsiptera (Insecta)
Systematic Entomology, 2016Co-Authors: Hans Pohl, Rolf G BeutelAbstract:. A single male specimen of a new species (†Kinzelbachilla ellenbergeri gen. et sp.n.) of a new family of the endoparasitic Strepsiptera (†Kinzelbachillidae fam.n.) from Burmese amber is described and evaluated with respect to its systematic placement. Its features come very close to the presumptive groundplan of the order suggested in recent studies. Preserved plesiomorphic features are the following: fully sclerotized head with long coronal suture, small ommatidia not separated by chitinous bridges, absence of microtrichia between ommatidia, eight antennomeres, robust mandibles with dicondylic articulation, galea distinctly developed, free pro- and mesotrochanters, slender five-segmented tarsi without adhesive soles, and equally sclerotized abdominal tergites and sternites. An important character that is not recognizable due to damage is the shape of the metapostnotum. This structure is transverse in the groundplan of Strepsiptera and in †Protoxenos, but elongated and shield-like in all other known Strepsipterans. In a cladistic analyses of 82 characters of adult males and additional characters for females and immatures (scored as unknown for all included fossils) †Kinzelbachilla is placed as sister group of all remaining Strepsipterans except for †Protoxenos, followed by †Cretostylops and †Mengea as the third and fourth branches in the stem group, respectively. The position of †Protoxenos as first branch is suggested by three unambiguous apomorphic features of all remaining Strepsiptera, the reduced size of less than 6 mm, mandibles distinctly narrowing distad the basalmost part, and fan-shaped hindwings which are broader than they are long. The hitherto known fossil stem group Strepsipterans do not distinctly narrow the large morphological gap separating this order from its sister group, the Coleoptera. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:07554C01-DEC3-4080-A337-B1F46BC9070F.
E. E. Ball - One of the best experts on this subject based on the ideXlab platform.
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The structure of the USP/RXR of Xenos pecki indicates that Strepsiptera are not closely related to Diptera
Development Genes and Evolution, 2005Co-Authors: D. C. Hayward, J. W. H. Trueman, M. J. Bastiani, E. E. BallAbstract:The receptor for the insect molting hormone, ecdysone, is a heterodimer consisting of the Ecdysone Receptor and Ultraspiracle (USP) proteins. The ligand binding domain sequences of arthropod USPs divide into two distinct groups. One group consists of sequences from members of the holometabolous Lepidoptera and Diptera, while the other arthropod sequences group with vertebrate retinoid-X-receptors (RXRs). We therefore wondered whether USP/RXR structure could be used to clarify the contentious phylogenetic position of the order Strepsiptera, which has proposed affinities with either Diptera or Coleoptera. We have cloned and sequenced the USP/RXR from the Strepsipteran Xenos pecki . Phylogenetic analyses are not consistent with a close affinity between Strepsiptera and Diptera.
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the structure of the usp rxr of xenos pecki indicates that Strepsiptera are not closely related to diptera
Development Genes and Evolution, 2005Co-Authors: D. C. Hayward, J. W. H. Trueman, M. J. Bastiani, E. E. BallAbstract:The receptor for the insect molting hormone, ecdysone, is a heterodimer consisting of the Ecdysone Receptor and Ultraspiracle (USP) proteins. The ligand binding domain sequences of arthropod USPs divide into two distinct groups. One group consists of sequences from members of the holometabolous Lepidoptera and Diptera, while the other arthropod sequences group with vertebrate retinoid-X-receptors (RXRs). We therefore wondered whether USP/RXR structure could be used to clarify the contentious phylogenetic position of the order Strepsiptera, which has proposed affinities with either Diptera or Coleoptera. We have cloned and sequenced the USP/RXR from the Strepsipteran Xenos pecki. Phylogenetic analyses are not consistent with a close affinity between Strepsiptera and Diptera.
Laura Beani - One of the best experts on this subject based on the ideXlab platform.
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Strepsiptera phylogenomics and the long branch attraction problem
PLOS ONE, 2014Co-Authors: Bastien Boussau, Zaak Walton, Isaac Stewart, Sydney A Cameron, James B Whitfield, Juan A Delgado, Francisco Collantes, Laura Beani, Spencer J JohnstonAbstract:Insect phylogeny has recently been the focus of renewed interest as advances in sequencing techniques make it possible to rapidly generate large amounts of genomic or transcriptomic data for a species of interest. However, large numbers of markers are not sufficient to guarantee accurate phylogenetic reconstruction, and the choice of the model of sequence evolution as well as adequate taxonomic sampling are as important for phylogenomic studies as they are for single-gene phylogenies. Recently, the sequence of the genome of a Strepsipteran has been published and used to place Strepsiptera as sister group to Coleoptera. However, this conclusion relied on a data set that did not include representatives of Neuropterida or of coleopteran lineages formerly proposed to be related to Strepsiptera. Furthermore, it did not use models that are robust against the long branch attraction artifact. Here we have sequenced the transcriptomes of seven key species to complete a data set comprising 36 species to study the higher level phylogeny of insects, with a particular focus on Neuropteroidea (Coleoptera, Strepsiptera, Neuropterida), especially on coleopteran taxa considered as potential close relatives of Strepsiptera. Using models robust against the long branch attraction artifact we find a highly resolved phylogeny that confirms the position of Strepsiptera as a sister group to Coleoptera, rather than as an internal clade of Coleoptera, and sheds new light onto the phylogeny of Neuropteroidea.
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non sibling parasites Strepsiptera develop together in the same paper wasp
Parasitology, 2008Co-Authors: Laura Vannini, Antonio Carapelli, Francesco Frati, Laura BeaniAbstract:SUMMARY Host discrimination by immature host-seeking endoparasites is a complex and somewhat unexplored topic. In the case ofmultiple infections, conflicts among conspecifics may occur to monopolize space and resources in the same host. Two ormore 1st instar larvae of Xenos vesparum (Strepsiptera, Stylopidae) may enter into a Polistes dominulus (Hymenoptera,Vespidae) larva and develop together until the adult stage of both parasite and host. We carried out a screening ofmitochondrial haplotypes in X. vesparum individuals extracted from superparasitized wasps taken in 5 naturally infectednests from different areas of Tuscany (Italy), to assess whether non-sibling parasites may infect the same colony and host.Intotal,weobtained12differenthaplotypesoutof122genotypedindividualsofbothsexes:17of34superparasitizedwaspshosted parasites that originated from females differing in their haplotypes. To date, this is the first described case ofsuperparasitism with non-sibling host-seeking larvae infecting a single individual hymenopteran host. In addition, at leastin heavily infected colonies, there is evidence of a male-biased sex-ratio and synchronous development of the parasites,regardlessoftheirhaplotypes.Finally,thedistributionofhaplotypespernestisconsistentwitheitherphoreticinfectionorlarvipositing on nests by means of superparasitized wasps.Key words: Strepsiptera, superparasitism, mtDNA, within-host competition.
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Developmental strategy of the endoparasite Xenos vesparum (Strepsiptera, Insecta): host invasion and elusion of its defense reactions.
Journal of Morphology, 2007Co-Authors: Fabio Manfredini, Fabiola Giusti, Laura Beani, Romano DallaiAbstract:To successfully complete its endoparasitic development, the Strepsipteran Xenos vesparum needs to elude the defense mechanisms of its host, the wasp Polistes dominulus. SEM and TEM observations after artificial infections allow us to outline the steps of this intimate host–parasite association. Triungulins, the mobile 1st instar larvae of this parasite, are able to “softly” overcome structural barriers of the larval wasp (cuticle and epidermis) without any traumatic reaction at the entry site, to reach the hemocoel where they settle. The parasite molts 48 h later to a 2nd instar larva, which moves away from the 1st instar exuvium, molts twice more without ecdysis (a feature unique to Strepsiptera) and pupates, if male, or develops into a neotenic female. Host encapsulation involves the abandoned 1st larval exuvium, but not the living parasite. In contrast to the usual process of encapsulation, it occurs only 48 h after host invasion or later, and without any melanization. In further experiments, first, we verified Xenos vesparum's ability to reinfect an already parasitized wasp larva. Second, 2nd instar larvae implanted in a new host did not evoke any response by hemocytes. Third, we tested the efficiency of host defense mechanisms by implanting nylon filaments in control larval wasps, excluding any effect due the dynamic behavior of a living parasite; within a few minutes, we observed the beginning of a typical melanotic encapsulation plus an initial melanization in the wound site. We conclude that the immune response of the wasp is manipulated by the parasite, which is able to delay and redirect encapsulation towards a pseudo-target, the exuvia of triungulins, and to elude hemocyte attack through an active suppression of the immune defense and/or a passive avoidance of encapsulation by peculiar surface chemical properties. J. Morphol., 2007 © 2007 Wiley-Liss, Inc.
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tiny genomes and endoreduplication in Strepsiptera
Insect Molecular Biology, 2004Co-Authors: J S Johnston, David P Hughes, Laura Beani, Larry Ross, Jeyaraney KathirithambyAbstract:Using flow cytometry, the genome sizes of two species of Strepsiptera were studied: that of male Caenocholax fenyesi texensis Kathirithamby & Johnston (Myrmecolacidae) at 108 Mb, which is the smallest insect genome documented to date; and those of male and female Xenos vesparum Rossi (Stylopidae), which are 1C = 130 and 133 Mb, respectively. The genome sizes of the following were analysed for comparative purposes: (a) the Hessian fly, Mayetiola destructor (Say), which was previously reported to be the smallest among insects: the male measured at 1C = 121 Mb and the female at 1C = 158 Mb; and (b) the female parasitic, haplodiploid, microhymenopteran wasp, Trichogramma brassicae Bezdenko, which measured at 1C = 246 Mb. The hosts of the Strepsipterans were also measured: male Solenopsis invicta Buren, the red imported fire ant (host of male C. f. texensis ), which is 1C = 753.3 Mb, and female Polistes dominulus Christ, the paper wasp (host of X. vesparum ), is 1C = 301.4 Mb. Endoreduplication (4C) of the genome of the thorax of the male Strepsipteran, and higher levels of endoduplication (4, 8, 16C) in the body of the larger female was observed. In contrast, little or no endoreduplication was observed, either in the Hessian fly, or in the parasitic wasp.
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prevalence of the parasite Strepsiptera in adult polistes wasps field collections and literature overview
Ethology Ecology & Evolution, 2004Co-Authors: David P Hughes, Jeyaraney Kathirithamby, Laura BeaniAbstract:The incidence of Strepsipteran parasites in temperate Polistes wasps is recorded following the collection and dissection of adults from nests, foraging sites and hibernacula. The mean proportion of infected P. dominulus adults (i.e. parasite prevalence) on nests was around 7%, while wasps which were captured when hunting for prey or collecting water were rarely parasitized. Of the four Polistes species that were recovered from overwintering aggregations (dominulus, gallicus, nimphus and associus) only P. gallicus was uninfected. In P. dominulus, the most numerous host sampled, up to 25% of overwintering females were infected. We discuss our findings in the light of an extensive collation of records of Polistes parasitized by the Strepsipteran genus Xenos in old and recent literature.
