Molecular cytogenetics in the study of repetitive sequences helping to understand the evolution of heterochromatin in Melipona (Hymenoptera, Meliponini).

The eukaryote genome is enriched by different types of repetitive DNA sequences and is most abundant in heterochromatin regions. Historically, no function has been assigned to these sequences, which makes them the target of studies that have demonstrated their structural and functional importance in the genome. Despite having a constant chromosome number, the genus Melipona has species with wide variation in heterochromatin content, from 8 to 73%, which is an important feature to be investigated regarding its origin and evolution. In the present study, a repetitive DNA sequence of Melipona mondury was isolated by restriction enzyme digestion. This sequence was used to hybridize chromosomes of eight Melipona species that include representatives of the four subgenera and present divergent characteristics in relation to the heterochromatin content. Considering that rDNA localization has shown differences in Melipona, 16 species of this genus were analyzed with 18S rDNA probe. Our data suggest that heterochromatin growth occurred independently in the Michmelia and Melikerria subgenera, considering that the isolated repetitive DNA sequence was shared only by the Michmelia species. Amplification possibly occurred from the centromeric region, causing the displacement of the rDNA sites to the ends of the chromosomes. The repetitive DNA sequence used is a constituent of Michmelia heterochromatin, which that arose from the common ancestor of the species of this subgenus.

Structure and Sense Organs of Ovipositors of an Endoparasitoid Aprostocetus causalis and an Ectoparasitoid Quadrastichus mendeli in Leptocybe spp.

Little is known of the olfactory mechanisms of host detection in the ovipositors of endoparasitoids and ectoparasitoids. An endoparasitoid Aprostocetus causalis La Salle & Wu (Hymenoptera: Eulophidae) and an ectoparasitoid Quadrastichus mendeli Kim & La Salle (Hymenoptera: Eulophidae: Tetrastichinae) are the two parasitoids of the eucalyptus gall wasp Leptocybe spp. Structures and sense organs of ovipositors of A. causalis and Q. mendeli were studied using scanning and transmission electron microscopy, which provided essential information for exploring the mechanism of host detection by endoparasitoid and ectoparasitoid. The ovipositors of two parasitoids consisted of the first and second valvulae and ended in a pointed tip. There were three types of microtrichia, two types of sensilla chaetica, and one type of sensilla campaniformia on the ovipositors of A. causalis and Q. mendeli. However, Q. mendeli has the fourth type of microtrichia on the ovipositor. The morphology, types, distribution, length, and width of these sensilla and microtrichia were described, and their possible functions are discussed in conjunction with the stinging, oviposition, and the host selection process.

Diversity and common themes in the organization of ocelli in Hymenoptera, Odonata and Diptera.

We show in a comparative analysis that distinct retinal specializations in insect ocelli are much more common than previously realized and that the rhabdom organization of ocellar photoreceptors is extremely diverse. Hymenoptera, Odonata and Diptera show prominent equatorial fovea-like indentations of the ocellar retinae, where distal receptor endings are furthest removed from the lens surface and receptor densities are highest. In contrast, rhabdomere arrangements are very diverse across insect groups: in Hymenoptera, with some exceptions, pairs of ocellar retinular cells form sheet-like rhabdoms that form elongated rectangular shapes in cross-section, with highly aligned microvilli directions perpendicular to the long axis of cross-sections. This arrangement makes most ocellar retinular cells in Hymenoptera sensitive to the direction of polarized light. In dragonflies, triplets of retinular cells form a y-shaped fused rhabdom with microvilli directions oriented at 60° to each other. In Dipteran ocellar retinular cells microvilli directions are randomised, which destroys polarization sensitivity. We suggest that the differences in ocellar organization between insect groups may reflect the different head attitude control systems that have evolved in these insect groups, but possibly also differences in the mode of locomotion and in the need for celestial compass information.

Antennal chemoreceptors in the European ectoparasitoid Sclerodermus cereicollis (Hymenoptera: Bethylidae).

Sclerodermus cereicollis is a European flat wasp ectoparasitoid of some longhorn beetle species. This species is important as a suitable biological control agent against xylophagous pests. To better understand its chemical ecology, the ultrastructure of the antennal sensilla of the adult was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The sensilla are located mainly in the ventro-medial side of the antennae. We report a clearly sexual dimorphism with respect to antennae length, and to types, number, and distribution of chemosensilla. The antennae in males are significantly longer than those of females. We describe in detail the external and internal structure of different chemoreceptors represented by sensilla placodea, long sensilla basiconica, multiporous sensilla chaetica, grooved sensilla ampullacea, uniporous grooved sensilla chaetica. The potential involvement of the different kinds of chemoreceptors in inter- (mainly sexual recognition and social behavior-kin recognition) or intra-specific communication (mainly host selection) is discussed on the basis of behavioral and electrophysiological investigations performed on other parasitoid species belonging to the same family. Other sensilla with morphology that is not consistent with that of chemoreceptors are represented by grooved pegs, coeloconic pegs, trichoid sensilla. Such detailed ultrastructural investigation of the flagellar chemoreceptors of S. cereicollis, clarifying the number of chemosensory neurons innervating the different sensilla, is crucial for further electrophysiological investigations on this important species. RESEARCH HIGHLIGHTS: Evident sexual dimorphism concerning antennae length, type, number, and distribution of chemosensilla. Long sensilla basiconica (LSB) present only in females could play a role in host location and/or maternal care. Multiporous sensilla chaetica (MSC), significantly longer and mostly represented in males, could play a role in the perception of sexual pheromones. Detailed ultrastructural study is crucial for electrophysiological investigations on this important species.

Integument and defence in larva and prepupa of a sawfly living on a semi-aquatic plant.

The larvae of the sawfly Rhadinoceraea micans live and feed on a semi-aquatic plant, Iris pseudacorus, and their integument is strongly hydrophobic. The hydrophobicity is part of a chemical defence strategy, easy bleeding, also known from congeners. The prepupae burrow into the soil where they form a cocoon in which they pupate, thus implying different micro-environmental conditions. The cuticle structure and wetting defensive effectiveness of R. micans were compared between larvae and prepupae. The two stages were similarly well defended against attacking ants by the bleeding of a deterrent hemolymph, whereas they were dissimilar in the cuticle surface that presented sculptures and wax crystals at the larval stage only. The integument of prepupae was less structured, and hydrophilic. Larvae of R. micans exhibit, among sawflies, an exceptional cuticle structuring and we assume that they occupy this particular niche of a semi-aquatic environment to avoid encounters with ground-dwelling predators whereas prepupae may benefit from the chemical defence acquired at larval stage.

Development, preimaginal phases and adult sensillar equipment in Aganaspis parasitoids (Hymenoptera: Figitidae) of fruit flies.

Aganaspis daci and Aganaspis pelleranoi (Hymenoptera: Figitidae) are important parasitoids of fruit flies. Here we studied, with light and scanning electron microscopy, aspects of their morphology that could help with plans to mass rear and thus contribute to improved pest control (preimaginal phases) and to shed light on parasitoid-pest relationships (sensillar equipment). The two species present a stalked egg, eucoiliform first and second-instar larvae and hymenopteriform third instar and mature larvae. The first instar presents tegumental differentiations in the mesoma and first metasomal segment in A. daci, but not in A. pelleranoi, while unlike other figitids, neither species displays setae in the mesosomal processes. Second and third instar and mature larvae present tegumental differentiations in A. daci, but not in A. pelleranoi. The moniliform (female) and filiform (male) antennae of A. daci and A. pelleranoi harbor seven types of sensilla, four of them (sensilla campaniformia, sensilla coeloconica type II, and two types of sensilla trichoidea) described here for the first time in Cynipoidea. The largest sensilla were the multiporous placoid sensilla, which were smaller and more numerous in A. pelleranoi. Species also differed to some extent in morphology of sensilla coeloconica. Observations on the ovipositor revealed the presence of coeloconic sensilla on Valva I in both species.

Revision of the species of Jaliscoa Boucek within a review of the identity, relationships and membership of Jaliscoa, Catolaccus Thomson, Eurydinoteloides Girault, Lyrcus Walker and Trimeromicrus Gahan (Hymenoptera: Pteromalidae).

The limits of Lyrcus Walker (1842), Catolaccus Thomson (1878), Eurydinoteloides Girault (1913a), Trimeromicrus Gahan (1914), and Jaliscoa Boucek (1993) are re-evaluated and redefined to better reflect observed distribution of morphological features. Nine of 13 New World species of Catolaccus are transferred to other genera and photographs of the primary type specimens are given to assist future recognition. New features are provided to assist identification of the remaining four Nearctic species of Catolaccus and these are compared to European species, with the observation that C. kansensis (Girault 1917c) could be a junior synonym of C. crassiceps (Masi 1911). Trimeromicrus is removed from synonymy under Lyrcus for the single species T. maculatus Gahan (1914) rev. comb. Newly synonymized under Lyrcus is the Australasian genus Neocylus Boucek (1988) n. syn. Ten species are newly transferred to Lyrcus-L. nigraeneus (Girault 1915) n. comb. (from Neocylus), L. helice (Walker 1843) n. comb. and L. cyaneus (Girault 1911) n. comb. (from Catolaccus), and L. albiclavus (Girault 1917c) n. comb., L. capitis (Burks 1955) n. comb., L. chalcis (Burks 1955) n. comb., L. coeliodis (Ashmead 1896) n. comb., L. deuterus (Crawford 1911) n. comb., L. nigroaeneus (Ashmead 1894a)n. comb. and L. rosaecolis (Burks 1955) n. comb. (from Zatropis Crawford 1908). Catolaccus pallipes Ashmead (1894b) is newly transferred to Pteromalus Swederus (1795) as Pteromalus pallipes (Ashmead) n. comb. and Catolaccus fragariae Rohwer (1934) to Lariophagus Crawford (1909) as Lariophagus fragariae (Rohwer) n. comb. Nine species are newly transferred to Eurydinoteloides-E. tepicensis (Ashmead 1895) n. comb. (from Catolaccus), E. dymnus (Walker 1847) n. comb., E. hermeas (Walker 1847) n. comb., E. incerta (Ashmead 1893) n. comb., E. orontas (Walker 1847) n. comb., E. perdubia (Girault 1916) n. comb., E. platensis (De Santis in De Santis et al. 1979) n. comb. and E. timaea (Walker 1847)n. comb. (from Lyrcus), and E. eudubia (Özdikmen 2011) n. comb. (from Spintherus Thomson 1878). Four species are newly transferred to Jaliscoa-J. grandis (Burks 1954) n. comb. and J. hunteri (Crawford 1908) n. comb. (from Catolaccus), and J. townsendi (Crawford 1912) n. comb. and J. vulgaris (Ashmead 1894b) n. comb. (from Pteromalus). The species of Jaliscoa are revised to include J. nudipennis Boucek 1993, J. bouceki n. sp., J. hunteri and J. vulgaris. Re-established in synonymy under J. hunteri is J. townsendi n. comb. One new species of Pteromalus, P. grisselli n. sp., is described as an egg predator in the egg sacs of Dictyna coloradensi Chamberlin (Araneae: Dictynidae) and compared to Catolaccus species and other pteromalids that are predators of spider eggs. Lectotypes are designated for Pteromalus helice Walker (1843), Catolaccus pallipes Ashmead (1894b) and Catolaccus vulgaris Ashmead (1894b). Diagnoses are given to differentiate Catolaccus, Eurydinoteloides, Jaliscoa, Lyrcus and Trimeromicrus from each other, and more extensive descriptions given to help differentiate these genera from other Pteromalinae. Morphological features are illustrated through macrophotography and scanning electron photomicrography.

Revision of the genus Aspicera Dahlbom, 1842 (Hym.: Figitidae: Aspicerinae).

The genus Aspicera Dahlbom (Hymenoptera: Cynipoidea: Figitidae: Aspicerinae) is revised herein. Aspicera has a Holarctic distribution, being here cited for the first time from the following countries: Canada, Cyprus, Greece, India (northeastern corner, which is part of the Himalayan southeastern range and is considered as belonging to the Palaearctic), Japan, Jordan, Mexico, Montenegro, and Turkey. Morphological characters necessary to differentiate the species of Aspicera are described. The 27 previously described species of Aspicera were revised, always studying the type material when available (21 species); the type material of A. aegyptica Hedicke, 1928, A. chlapowskii Kieffer, 1901, A. coriacea Kieffer, 1901, A. lobata Hedicke, 1928, A. sibirica Kieffer, 1901, A. spinosa (Boyer de Fonscolombe, 1832) are lost or destroyed, these species were studied with the original descriptions. Of the 27 known species, 16 are considered as valid and are redescribed; A. effincta Belizin, 1952 is syn. nov. of A. suecica Dalla Torre & Kieffer, 1910, and A. brevispina Kieffer, 1901 and A. coriacia Kieffer, 1901 are syn. nov. of A. hartigi Dalla Torre, 1889. Aspicera nigra Ionescu, 1969, A. nigricornis Kirby, 1889 and A. rugosa (Hartig, 1843) do not belong to the Aspicerinae, but respectively to the genera Xyalophora and Neralsia (Figitinae), and Xyalaspis (Anacharitinae): Xyalophora nigra (Ionescu) n. comb., Neralsia nigricornis (Kirby) n. comb. and Xyalaspis rugosa Hartig status restored. Aspicera lobata Hedicke, 1928 is considered as 'incertae sedis'. The examination of additional specimens suggests that there is a general lack of knowledge of the species diversity of this genus. Thirty two new species are described: A. adelae Ros-Farré n. sp., A. annae Ros-Farré & Pujade-Villar n. sp., A. belizini Ros-Farré & Pujade-Villar n. sp., A. blancae Ros-Farré n. sp., A. buffingtoni Ros-Farré & Pujade-Villar n. sp., A. caminali Ros-Farré n. sp., A. carinata Ros-Farré & Pujade-Villar n. sp., A. dianae Ros-Farré n. sp., A. kovalevi Ros-Farré & Pujade-Villar n. sp., A. elisendae Ros-Farré n. sp., A. forshzarai Pujade-Villar & Ros-Farré n. sp., A. gemmae Ros-Farré & Pujade-Villar n. sp., A. jantonii Ros-Farré n. sp., A. julii Ros-Farré & Pujade-Villar n. sp., A. kiefferi Ros-Farré & Pujade-Villar n. sp., A. magdae Ros-Farré & Pujade-Villar n. sp., A. marginata Ros-Farré & Pujade-Villar n. sp., A. martae Ros-Farré & Pujade-Villar n. sp., A. danielssoni Ros-Farré & Pujade-Villar n. sp., A. carlestolrai Ros-Farré & Pujade-Villar n. sp., A. mireiae Ros-Farré & Pujade-Villar n. sp., A. porif Ros-Farré n. sp., A. marginata Ros-Farré & Pujade-Villar n. sp., A. punctifrons Ros-Farré & Pujade-Villar n. sp., A. readae Ros-Farré & Pujade-Villar n. sp., A. robusta Ros-Farré & Pujade-Villar n. sp., A. santamariai Ros-Farré & Pujade-Villar n. sp., A. sergioi Ros-Farré n. sp., A. singularica Ros-Farré & Pujade-Villar n. sp., A. teresae Ros-Farré n. sp., A. tomasi Ros-Farré n. sp., A. zuparcoi Ros-Farré & Pujade-Villar n. sp. A key to all 48 valid species of Aspicera is given. All species are illustrated.

Morphology and location of sensilla in the antennae and ovipositor of Sirex noctilio (Hymenoptera: Siricidae).

The woodwasp Sirex noctilio Fabricius is a major quarantine pest that was reported in China in 2013 and mostly damages Pinus sylvestris var. mongolica. Reverse chemical ecology, which uses chemical lures to catch or block insects from mating is the classic way to control forestry pests. This indicates that insect sensilla play a crucial role in detecting external chemical and physical stimuli. Nonetheless, the categorization and distribution of sensilla on the antennae and ovipositor of S. noctilio are insufficiently specific. In this paper, scanning electron microscopy (SEM) was used to observe the ultrastructure of the sensilla of S. noctilio on the antenna and ovipositor. It was found that the types and distribution of sensilla on the antennae of S. noctilio male and female are consistent, and six types of sensilla are found: sensilla trichodea (ST), sensilla chaetica (SC), Böhm bristles (BB), sensilla basiconica (SB), sensilla ampullacea (SA), and contact chemoreceptors (CC). Besides, there are five types of sensilla on the female ovipositor. In addition to ST, SC and BB, two more types of sensilla are also found: sensilla cavity (SCa) and sensilla coeloconica (SCo). Through identification of the morphology and distribution of the sensilla, the functions of different sensilla in the mating and host selection mechanisms of S. noctilio are proposed, thereby establishing a foundation for S. noctilio chemical communication research.

Morphology and ultrastructure of antennal sensilla of the parasitic wasp Baryscapus dioryctriae (Hymenoptera: Eulophidae).

Baryscapus dioryctriae is an endoparasitic wasp in the pupae of many Pyralidae pests, such as Dioryctria mendacella, Ostrinia furnacalis, and Chilo suppressalis. To provide requisite background for our ongoing research on the mechanisms of host location in B. dioryctriae, the morphology, abundance, distribution, and ultrastructure of the antennal sensilla were investigated using scanning and transmission electron microscopy. The geniculate antennae of B. dioryctriae are composed of scape, pedicel, and flagellum. Eight types of sensilla including Böhm sensilla, chaetica, trichodea, basiconic capitate peg, campaniformia, placodea, coeloconica, and sensilla styloconicum with a long hair were identified on both sexes. Sexual dimorphism exists in the antennae of B. dioryctriae. The number of flagellomere in males is over females, and the subtypes and abundance of sensilla are also different between the sexes. Additionally, the possible functions of distinct sensilla were discussed, which varies from olfaction, contact chemoreceptive, mechanoreception to hygro-/thermoreception, especially, the sensilla trichodea and placodea might be involved in olfactory perception in B. dioryctriae. These results provide an essential basis for further study on chemical communication between B. dioryctriae and their hosts, and contribute to the development of B. dioryctriae becoming an effective biocontrol agent against the pests of agriculture and forestry.

Characterization of abdominal appendages in the sawfly, Athalia rosae (Hymenoptera), by morphological and gene expression analyses.

Larvae of the sawfly, Athalia rosae, have remarkable abdominal prolegs. We analyzed the morphogenesis of appendages and the expression of decapentaplegic and Distal-less genes during embryonic development to characterize the origin of prolegs. Proleg primordia in abdominal segments A1-A9 appeared shortly after the inner lobes (endites) of gnathal appendages were formed. These were located on the ventral plates, medioventral to the appendages of the other segments in light of serial homology. Nothing was seen where the main axis of the appendage should develop in abdominal segments. The primordia in A1 and A9 disappeared before larval hatching. Anal prolegs appeared separate from cerci, the main axes of appendages, which were formed temporarily in A11. The expression of decapentaplegic, which reflects the primary determination of appendages, was detected in the lateral juxtaposition with the prolegs. Distal-less was expressed in the main axes of appendages, protruding endites and the cerci, but not in prolegs and anal prolegs or the gnathal endites which do not protrude. These findings suggest a possibility that the abdominal and anal prolegs of A. rosae are outgrowths of ventral plates which derived from coxopodal elements, but not main axes of appendages.

Sperm structure and ultrastructure of the Melittobia hawaiiensis, Perkins and M. australica, Girault (chalcidoidea: eulophidae).

Spermatozoa morphology has, for some years, been used to help answer some phylogenetic questions for Hymenoptera. This is the second study describing spermatozoa morphology of an Eulophidae species in which important characteristics were observed. Melittobia spermatozoa are spiralled and measure approximately 270microm in length. The head contains a small acrosome, apparently formed only by an acrosomal vesicle, which, together with the initial nuclear region, is surrounded by an extracellular sheath, from which innumerable filaments irradiate. The nucleus is helicoidal and completely filled with compact chromatin. A centriolar adjunct is observed at the nucleus-flagellum transition; it associates laterally with the nucleus and exhibits two small expansions, which reach around the centriole. In the flagellum there are two mitochondrial derivatives, which in cross-sections are asymmetric. In the derivative with the larger diameter, two distinct regions are observed, a small one, near the axoneme, with a clear "fissure" inside, and a larger region where the cristae occur. Both derivatives initiate at the nuclear base, but the larger diameter derivative finishes first, before the flagellum extremity. At the end of the axoneme, the accessory microtubules are the first to finish.

The preimaginal phases and development of Pachycrepoideus vindemmiae (Hymenoptera, Pteromalidae) on Mediterranean fruit fly, Ceratitis capitata (Diptera, Tephritidae).

The development and morphology of the immature phases of Pachycrepoideus vindemmiae (Rondani, 1875) (Hymenoptera, Pteromalidae) are described from a laboratory rearing culture maintained on Ceratitis capitata (Wiedemann, 1824) (Diptera, Tephritidae) using microscopic techniques, including light and scanning electron microscopy. The surface of the chorion of the egg is granulated, and the micropyle occurs at the anterior end. The labrum of the first instar larva does not have sensilla, and the second to fourth instar larvae have setae on the head. The mature larva is characterized by the position and number of the integumental differentiations (sensilla and setae). On completion of larval development, an adecticous and exarate pupa is produced. As for the adult, the mandibles of the pupae are toothed. Five larval instars are recorded, based on statistical analyses of the sizes of the larval mandibles in combination with characters such as the number of exuviae and excretion of the meconium. Developmental time from egg to adult emergence was 18-20 days for males and 21-23 days for females at 21-26 degrees C, 55-85 relative humidity, and a 16L:8D photoperiod. The results show that the eggs and different larval instars of this parasitoid can be unambiguously identified only by scanning electron microscope.

Morphology and distribution of antennal sensilla in egg parasitoid, Ooencyrtus nezarae (Hymenoptera: Encyrtidae).

Morphology of antennal sensilla and their distribution were investigated in adults of Ooencyrtus nezarae, an egg parasitoid of Riptortus pedestris, using scanning electron microscopy. Male antennae was found to be significantly greater in overall length than female antennae. The antenna of O. nezarae was composed of the radicula, scape, pedicel, funicle and clava in both sexes, with seven types of sensilla identified: sensillum trichodea; s. finger-like; s. placoidea; s. chaetica; s. basiconica; s. coeloconica, and s. campaniform. They occur in varying number and distribution along the antennae. Two sensillum types were further categorized into additional subtypes, with two subtypes in s. trichodea and three in s. chaetica. Among all characterized sensilla, s. trichodea subtype 1 and s. placoidea were multiporous, indicating that the primary function of these sensilla is olfactory. Sensillum trichodea was the most abundant sensillum type on the antennae of both sexes. Sexual dimorphism was only observed from the subtype 1 sensilla of s. trichodea in males and the subtype 3 sensilla of s. chaetica in females. The morphological information established in our study may provide useful information for further investigations in sensory physiological function of each morphological type of sensilla and their related behavior in this egg parasitoid.

Scanning electron microscopy studies of antennal sensilla of Pteromalus cerealellae (Hymenoptera: Pteromalidae).

Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae) is an ectoparasitoid of several insect pests of stored products. In order to provide requisite background information to support our ongoing research on its host location mechanisms, we examined the external morphology of the antennal sensilla of this parasitoid using scanning electron microscopy. Antennae of male and female P. cerealellae are geniculate in shape, approximately 1300mum in length, and consist of 15 antennomeres. Eight morphological sensilla types were recorded in both sexes, including four types of the highly abundant and widely distributed sensilla trichodea (types I, II and IV are aporous while type III is multiporous), basiconic capitate peg sensilla, coeloconic sensilla, chaetica sensilla, and the most conspicuous plate-like placoid sensilla. Detailed examination of sensilla morphological features including pore presence and numbers suggest that the multiporous type III sensilla trichodea and the multiporous placoid sensilla may play a role in olfaction, whereas the uniporous chaetica sensilla may function as contact chemoreceptors. The types I and II sensilla trichodea are presumably mechanosensory, while the type IV sensilla trichodea may function as proprioceptors. The basiconic capitate peg sensilla and coeloconic sensilla probably function in thermo-hygro reception. Although the shape, structure, and size of antennae of males and female were basically similar, major differences were recorded between the sexes in the distribution of some sensilla types. The type II sensilla trichodea and the multiporous placoid sensilla are relatively more abundant in females, whereas males have greater number of the multiporous type III sensilla trichodea than females. These results are discussed in relation to the possible roles of the sensilla types in the host location behavior of P. cerealellae.

Structure and sensory equipment of the ovipositor of Habrobracon hebetor (Say) (Hymenoptera: Braconidae).

The microsculpture of various structures of the ovipositor of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is described from scanning and transmission electron microscopy. These include: the ovipositor egg canal, valvillus, seal of the first valvulae, interlocking mechanism (olistheter) connecting the first and second valvulae, an olistheter-like interlocking mechanism connecting the two pieces of the first valvulae, annulation, microtrichia of the third valvulae, and the ovipositor sensory equipment. Better understanding of the microsculpture of these components may make their roles in stinging, oviposition, and the host selection process more clear.

The short spermatodesm of Arge pagana (Hymenoptera: symphyta).

In the seminal vesicle of the 'symphyta'Arge pagana the spermatozoa are stored in motile spermatodesm bundles, maintained by an anterior cap of extracellular material. This cap consists of a denser cortex and of an internal matrix, where part of the sperm heads are embedded. The number of spermatozoa per bundle is variable. The spermatozoa are short, only 30microm long, with a head region of about 23microm, and a very short flagellum of about 7microm. The head includes the acrosome, with a perforatorium, and the nucleus. The flagellum consists of an axoneme, with a 9+9+2 microtubule pattern, a centriolar adjunct, two mitochondrial derivatives and two accessory bodies. The mitochondrial derivatives are very slender and of different lengths. The longer begins at the base of the nucleus, while the shorter one starts just below the base of the centriolar adjunct. This latter is asymmetric and appears at the nuclear base, extending parallel to the axoneme up to the anterior end of the smaller mitochondrial derivative. The short spermatodesmata and the small mitochondrial derivatives characterize the A. pagana sperm. In addition, the centriolar adjunct asymmetry and the occurrence of spermatodesm bundles might be considered plesiomorphic states present in the basal Tenthredinoidea.

Ultrastructure of the single-chamber stemmata of Arge pagana (Panzer, 1798) (Hymenoptera: Argidae).

Stemmata are peculiar visual organs of most larvae in holometabolous insects. In Hymenoptera, Symphyta larvae exclusively possess a pair of stemmata, whose cellular organizations have not been thoroughly elucidated to date. In this paper, the morphology and fine structure of stemmata were investigated in the large rose sawfly Arge pagana (Panzer, 1798) using light and electron microscopy. The larvae possess a pair of stemmata, which belong to the "unicorneal composite eye" or single-chamber stemmata. Each stemma is composed of a biconvex cornea lens, a layer of corneagenous cells, numerous pigment cells, and hundreds of retinula cells. According to the number of retinula cells forming a rhabdom, the stemma can be divided into two regions, the larger Region I and the smaller Region II. The former occupies the largest area of the stemma and contains the majority of rhabdoms, each of which is formed by the rhabdomeres of eight retinula cells. The latter occupies a narrow posterior margin, where each rhabdom consists of nine retinula cells. Based on the different cellular organizations of rhabdoms, the stemma of Argidae is likely developed by the fusion of two types of ommatidial units.

Domestic infestation by Sclerodermus sp. with associated skin manifestation.

Sclerodermus sp. is an aculeate insect (Hymenoptera: Bethylidae), measuring 2-4 mm in length. It is a parasitoid and needs termites as hosts to complete its life cycle. It is found in a wide variety of woods and may accidentally sting humans who come near affected wooden objects. A 50-year-old woman presented two episodes of intense pruritic lesions. Clinical diagnosis of insect bite was doubtful since there were no pets at home, lesions had not started during summer and the patient denied rural activities. During a night episode of itching, the patient examined her bed and found 8 insects likely to be responsible for the bites. Scanning electron microscopy revealed typical features of a female of the genus (wingless and with multiple stingers at the lower end of the abdomen).

Sensilla on organs of female and male Aphidius gifuensis (Hymenoptera: Aphidiidae).

Aphidius gifuensis Ashmaed parasitizes several species of aphids that cause economic damage to globally important crops; however, the mechanism of host location in this species is unclear. Here, we studied the sensory system in A. gifuensis to explore the likely mechanisms of host location that could be useful in the improved application of this species in aphid biological control programs. We used scanning electron microscopy to observe the external morphologies of the sensilla recorded from the entire body of female and male A. gifuensis. We recorded 16-18 segments and five types of sensilla on female antennae, including Böhm bristle, Chaetica sensillum, basiconic sensillum, trichoid sensillum, and placodea sensillum. The male antennae consisted of 18-20 segments, and distribution of sensilla was similar to female antennae with minor differences. No hole on the surface or tip of the sensilla was observed. Interestingly, scattered pores around the TS were found on the entire body of females, but only from the antennae, abdomen, and thoracic legs in males. TS was the most abundant and widely distributed sensillum. Tympana structures were found on antennae and femur of thoracic legs. Antenna cleaner was found on the tibia of propodeum and wing cleaner was found on the tibia of metapedes. Special crevice-shaped structures were found on the abdomen in both sexes, whereas strip-shaped structures were found only on the abdomen of females. Possible functions of the sensilla in relation to their morphologies are discussed.