Comparative morphology of the antennal “release and spread structure” associated with sex pheromone-producing glands in male Cynipoidea

Mating behaviour in insects is largely mediated by chemical signals emitted by one sex and recognized by the other (sex pheromones). A particular type of integumentary gland produces a sex pheromone in the antennae of male Cynipoidea (Hymenoptera), a rich and diverse wasp group consisting of species forming galls on plants, species which act as inquilines or parasitoids of these galls, and non-gall-associated parasitoids. This gland is connected to the surface by a modified structure which releases and spreads the chemicals on females (release and spread structure (RSS)). Here, we performed a scanning electron microscope investigation to evaluate the diversity of RSS in detail through an analysis of 49 species spanning almost all extant lineages, with special emphasis on the family Cynipidae (gall-wasps). Up to three strongly modified flagellomeres harboured the RSS in Cynipoidea, more often the first (proximal) flagellomere (F1). The F1was in most cases cylindrical or slightly flattened laterally, in this case often with a longitudinal ridge present, with few cases of a distinctly excavated (only in Cynipidae and the basal parasitoid family Ibaliidae) or strongly distally inflated (only in the cynipid gall-inquiline tribe Synergini) shape. The RSS ranged from long and narrow to short and wide. Pores of the RSS, more often scattered than closely spaced, were well visible in most of species. The observed conspicuous variability in RSS morphology seemed very weakly associated both with phylogenetic relationships among lineages and with life-history (galler, gall-associated inquilines or parasitoids, and non-gall-associated parasitoids). New studies are necessary to shed light on the evolution of this structure

Antennal sensilla in male gall-wasps (Hymenoptera: Cynipidae) and insights on the evolution of sexual dimorphism in cynipoid sensory equipment

The diversity of insect antennal structures involved in communication is still poorly known because of the limited number of comparative studies and as such studies often exclusively focus on one sex. Within Cynipoidea, a recent study on female gall-wasps (Hymenoptera: Cynipidae) and some of their non-gall associated relatives (Ibaliidae and Figitidae) showed a great diversity of the antennal sensillar equipment both between and within lineages. In order to better understand possible patterns of this diversity, we here present a study in males. By Scanning Electron Microscopy analysis of 45 species of Cynipoidea (30 of them gall-wasps) from most known lineages, we found that the male antennal flagellum is generally filiform and bears overall eight types of sensilla: s. placoidea (SP), s. coeloconica (SCo-A), s. campaniformia (SCa), s. basiconica (SB) and s. trichoidea (ST-A, ST-B, ST-C, ST-D) (5\u20138 types per species). The number, size and arrangement of sensilla greatly varied among and within cynipoid lineages, with only a partial effect of phylogeny on this variation. By using data of 27 species for which both sexes were analysed, we found that males generally possess a lower number of sensillar types than females in gall-inducers and a greater number of sensillar types than females in non-gall-inducers. Sexes shared 40\u2013100% of sensillar types independently from their biology. Males seem to possess an overall greater number of SP than females, with a weak tendency of such difference to be larger in gall-inducers. A possible hypothesis is that gall-inducing female cynipids may have evolved a richer sensillar equipment in response to female-only activities (e.g. plant host recognition), while cynipid males may have evolved higher density of sensilla devoted to mate recognition

Catalogue of parasitoids and inquilines in galls of Aylacini, Diplolepidini and Pediaspidini (Hym., Cynipidae) in the West Palaearctic

International audienceA quantitative catalogue of the regular members of the parasitoid and inquiline communities inhabiting cynipid galls of the tribes Aylacini, Diplolepidini and Pediaspidini in the western Palaearctic is presented. Quantitative and national data are included. There follows a checklist of the parasitoid (almost entirely Chalcidoidea) and inquiline species, with their cynipid hosts. The communities in galls of the three tribes are compared with those associated with Cynipini. Inquiline Cynipidae are well represented in Diplolepidini and Cynipini gall communities, but absent from galls of the other two tribes, although an inquiline eulophid (Dichatomus) develops in galls of Pediaspidini. The great majority of the parasitoids encountered belong to six families of Chalcidoidea that are all represented in Aylacini, Diplolepidini and Cynipini communities, except Ormyridae which have not been found in Pediaspidini galls. Representation of the chalcidoid families varies in the parasitoid faunas of different cynipid tribes, with species of Eurytomidae most abundant in Aylacini galls, Torymidae in Diplolepidini galls, Eupelmidae in Pediaspidini galls and Eulophidae in Cynipini galls. Pteromalidae are evenly represented in galls of all tribes. With the exception of Eupelmidae, which are mostly very polyphagous, few parasitoid species are regularly associated with more than a single tribe of Cynipidae. However, examples of parasitoid species attacking gall wasps in the 'wrong' tribes are not rare. While species diversities of the parasitoid communities of Cynipini are high, those of Aylacini are relatively low. The varied nature of galls of Cynipini, all on Quercus, creates a multiplicity of niches for the parasitoids, and these are mostly polyphagous attacking hosts in a range of galls. In contrast, galls of Aylacini present much less structural diversity, but they occur on several genera and families of host plant, and their parasitoids are, in general, less polyphagous and restricted to hosts on a more or less taxonomically limited host plant rang

Distributions of sawflies and aculeates in a heterogenous secondary acid forest in Artikutza (Navarre) (Insecta : Hymenoptera)

La distribución de las especies de sínfitos y aculeados ha sido investigada por medio de seis trampas Malaise instaladas en dos series de vegetación adyacentes y sucesivas, bosque mixto de pinos y hayedo, en la reserva forestal de Arikutza (Navarra). La comparación entre series de vegetación y localización de las trampas en sínfitos, avispas, abejas y hormigas sugiere que la distribución de las especies puede estar relacionada con la distribución espacial de los distintos recursos de alimentación, reproducción, nidificación o hibernación. Los claros, el cauce del río y la madera muerta proveen variedad de fuentes de diversidad

Ácaros oribátidos (Acari: Oribatei) del Parque Nacional de la isla de Coiba, Panamá

Dentro del programa para el inventario de la fauna y flora del Parque Nacional de la Isla de Coiba (Panamá), se presenta un primer listado de los ácaros oribátidos (Acari: Oribatei) que habitan en el parque. El material objeto de este estudio, procede de diversos muestreos edáficos, incluyendo hojarasca y humus, realizados en el sitio en julio de 1998. Para un total de 1 053 ejemplares colectados en las muestras se han identificado 134 especies diferentes, de las cuales, practicamente todas son nuevas para Panamá y 8 especies se citan por vez primera en la región neotropical. Se da un nuevo nombre: Aeroppia mariehammerae n.nom. para Aeroppia sp. (Hammer, 1962) y una combinación nueva para Protoribates antillensis (Mahunka, 1985) n. comb. (Xylobates)Taking part of the Program for The Inventory of Flora and Fauna of Coiba Island National Park (Panamá), a first list of oribatid mites (Acari: Oribatei) is presented. Materials studied come from several soil samplings, including humus and fallen leaves, done in Coiba Island in July 1998. 134 species were identified from a total amount of 1 053 individuals collected. Almost all the identified species are new records for Panamá as well as eigth species that represent first records for the Neotropical Region. A new name is given: Aeroppia mariehammerae n. nom. for Aeroppia sp. and a new combination is proposed: Protoribates antillensis (Mahunka, 1985) n. comb. (Xylobates

Climate as a possible driver of gall morphology in the chestnut pest Dryocosmus kuriphilus across Spanish invaded areas

The alien cynipid wasp Dryocosmus kuriphilus Yasumatsu, 1951 is a serious pest of chestnuts (Castanea spp.) in Japan, North America and Europe, causing fruit losses while inducing galls in buds. While D. kuriphilus galls have a recognizable and roughly invariable globular shape, their size varies, reaching up to 4 cm in diameter. Among other factors, such variation may depend on different climatic conditions in different attacked areas. Here, we sampled and measured 375 D. kuriphilus galls from 25 localities throughout the Iberian Peninsula, including both cold and rainy northern (Eurosiberian) areas and warm and dry central-southern (Mediterranean) areas, to test the effects of climate and geographical location on gall morphology. The analyses indicate that gall mass and volume follow a pattern that can be associated with a climatic cline. In particular, the Eurosiberian galls were smaller than the Mediterranean galls according to differences in climatic conditions. In the southern areas, the greater insolation regime does not allow the chestnut trees to be distributed at lower altitudes, but the high rainfall and humidity regime of the mountain enclaves allow their presence. These conditions of insolation and precipitation seem to influence the morphological characteristics of the galls of D. kuriphilus

Strong phylogenetic constraint on transition metal incorporation in the mandibles of the hyper-diverse Hymenoptera (Insecta)

In several groups of insects, body structures related to feeding and oviposition are known to have a hardened cuticle by incorporation of transition metals. However, a functional link between metal enrichment and ecological pressures (i.e., adaptation) has been only rarely shown, opening the possibility that in some lineages, the evolutionary history may account for most of the observed variation (i.e., phylogenetic constraint). Here, we addressed this question in the hyper-diverse Hymenoptera (bees, wasps, ants, and sawflies), in which Zn and/or Mn have been found enriching the mandibles of a number of species. Across 87 species spanning most of the extant superfamilies, we found Zn enrichment to be widespread (57 species). Although lacking in the most primitive \u201cSymphyta\u201d, our ancestral state reconstruction was not conclusive in determining whether Zn enrichment was a derived state for the complete order, but it was clearly the ancestral state for the Apocrita, where it was lost in few lineages, notably in Aculeata (where it was then reacquired at least three times). Mn, on the other hand, occurred very rarely in mandibles (10 species). Our comparative analysis revealed a strong phylogenetic effect explaining most Zn % and Mn % variation in mandibles. Additionally, species with herbivorous larvae were less prone to have Zn (but not Mn) than those with carnivorous larvae, although a causal effect of diet on this trait was unlikely. Furthermore, species emerging from concealed vs. unconcealed development sites have similar likelihood to have metal-enriched mandibles. Evolutionary history seems to constrain metal enrichment in hymenopteran mandibles, yet the few observed losses and regains of this trait during evolution claim for deeper investigations on the role of alternative, here untested, ecological pressures

Recent advances in the genus- and species level molecular systematics of the Cynipini

The taxonomy of oak gallwasps (Hymenoptera: Cynipidae: Cynipini) has a long and sometimes confusing history. Many large genera have become hold-alls for a diversity of lineages, and are often delimited by combinations of pleisiomorphic character states. At species level, the presence of alternating generations further complicates Cynipini taxonomy. With the increased use of molecular systematics, it is clear that current Cynipini taxonomy is inadequate and requires major revisions. Here we provide an overview of recent work helping to resolve the chaotic mess of Cynipini taxonomy. Some of this work has involved purely morphological re-assessment of particularly distinctive lineages, while much is based upon ongoing systematic work using a 6-gene molecular phylogeny containing 430 species representing all the known major lineages/genera within the Cynipini. Incorporation of phylogenetic information has revealed that all of the large, Holarctic-distributed genera are polyphyletic. In addition, the limits of many smaller genera require redefining, and widespread sampling indicates that many of these genera may be represented by a larger complement of species across a broader geographic area. Molecular data also provide a quick and simple method for matching alternate generations of Cynipini species. Development of collection genomics workflows has opened up biological collections to molecular analysis, potentially providing DNA sequence data for matching generations. Within Cynipini, this could allow for the sizeable series of specimens collected by early researchers such as Kinsey and Weld to be used for clarifying the species-level taxonomy of large numbers of Cynipini taxa