Search results for "Hymen"
showing 10 items of 287 documents
Low parasitism rates in parthenogenetic bagworm moths do not support the parasitoid hypothesis for sex
2012
The parasite hypothesis for sex is one of the many theories that have been suggested to solve the mystery of the widespread occurrence of sex despite its high short-term costs. It suggests that sexual lineages have an evolutionary advantage over parthenogens because they can frequently generate new genotypes that are temporarily less prone to coevolving parasites. In this study, we looked for further supporting evidence for the parasite hypothesis of sex in an attempt to understand the coexistence of sexual and parthenogenetic bagworm moths (Naryciinae). The bagworm moths and their parasitoids form one of the few natural host-parasite systems where sexual and parthenogenetic hosts are appar…
Venom gland and reservoir morphology in the Doryctinae and related braconid wasps (Insecta, Hymenoptera, Braconidae)
1992
Detailed venom reservoir and venom gland intima morphology has been investigated in reprsentatives of 84 genera and 10 subfamilies of Braconidae with particular reference to the Doryctinac, basal cyclostomes and related groups including the Opiinae, Alysiinae and Rogadinae sens. lat. Several new phylogenetically significant characters are described and illustrated. Extcnsivc secretory ductules on the primary venom duct is suggested as a synapomorphy for the subfamilies Braconinac, Doryctinae, Opiinae, Alysiinae and Gnamptodontinae. The presence of two separate venom gland insertions and their position beyond the spiral sculpture of the reservoir are suggested as synapomorphies for the subfa…
World revision of the genus Encyrtoscelio Dodd (Hymenoptera: Scelionidae)
1995
The genus Encyrtoscelio Dodd is revised. E. apterus (Szelényi), E. mirissimus Dodd, E. turneri Waterston are redescribed, and six new species are described: E. cydni Caleca, E. japonicus Caleca, E. mediterraneus Caleca, E. miroides Caleca, E. spuratus Caleca and E. undecim Caleca. A key to separate females is presented, and is based on the number of antennomeres and claval sensillar formula, mandibular spurs and teeth, palpal formula and clypeus, and some cephalic characters. Morphological adaptations of the head and mandibles are discussed in relation to host habitat and oviposition site. Information on host associations, habitat preference, seasonal and daily occurrence of some species a…
The Taxon Rasivalva (Hymenoptera: Braconidae) in the Palaearctic Region and Description of Rasivalva pyrenaica New Species from Andorra
2005
Rasivalva appears to be an uncommon genus, although it is nearly cosmopolitan with the exception of the Australian continent. Five species have been recorded from Europe and Crimea. In this paper, Rasivalva pyrenaica n. sp. is described as the most southern Palaearctic record of this genus, as well as the first record of the genus from Iberian Peninsula. An identification key is proposed for the Palaearctic species.
Two new records of Alloxysta (Hymenoptera: Cynipoidea: Figitidae: Charipinae) from Colombia
2016
The Charipinae from Colombia has been recently studied. Nine Charipinae species are known to be present in this country: Alloxysta arcuata (Kieffer, 1902), Alloxysta castanea (Hartig, 1841), Alloxysta consobrina (Zetterstedt, 1838), Alloxysta hansoni Pujade-Villar, 2011, Alloxysta obscurata (Hartig, 1840), Alloxysta medinae Ferrer-Suay & Pujade-Villar, 2012, Alloxysta pilipennis (Hartig, 1840), Alloxysta torresi Ferrer-Suay & Pujade-Villar, 2012 and Phaenoglyphis villosa (Hartig, 1841). Here more Charipinae material has been studied from collections made with Malaise traps by the Humboldt Institute in several places of Colombia. In this study, two species are recorded for the first …
High winter survival rate of acorn ants inside artificial nest sites (Hymenoptera: Formicidae)
2022
Although most species of ants overwinter underground to avoid low temperatures, the acorn ants of the genus Temnothorax remain in nests situated at ground level. During a field experiment, I studied the winter mortality of acorn ants in nest sites situated aboveground, as well as in sites experimentally buried in the soil. Despite the low air temperatures (even reaching –19°C, recorded 1.5 m above the ground), the survivorship was very high: all of the 18 queens used in the experiment survived, while the survival rate of workers was 61.9-100%, and for most colonies it exceeded 95%. The rate of survival in the nest sites aboveground and those experimentally buried in the soil was similar. Su…
Cost to the cavity-nest ant Temnothorax crassispinus (Hymenoptera : Formicidae) of overwintering aboveground
2013
Most species of ants inhabiting the temperate zone overwinter underground, whereas those of the genus Temnothorax remain in nests aboveground. I studied the cost of aboveground overwintering. Workers of Temnothorax crassispinus survived in higher numbers (median = 88%) in artificial nests experimentally buried at a depth of 5 cm than those in nests on the surface (48%) of the soil. The results support the hypothesis that overwintering aboveground could be a consequence of a limited supply of nests and/or the advantage of being able to respond quickly to warm temperatures in spring.
Sub-lethal effects of deltamethrin on walking behaviour and response to host kairomone of the egg parasitoid Trissolcus basalis.
2002
The lethal doses of the pyrethroid deltamethrin were estimated for the egg parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae), and the sub-lethal effects of an LD25 on female walking behaviour were evaluated. Linear speed of treated parasitoids was reduced compared with that of untreated ones for a period of up to 24 h. The sub-lethal effects of deltamethrin on parasitoid response to patches contaminated by a contact kairomone from its host, Nezara viridula L (Heteroptera: Pentatomidae), was also evaluated. Both treated and untreated parasitoids responded to host-contaminated patches by increasing residence time and decreasing linear speed. However, treated females showed …
Hymenoptera Chalcidoidea inhabiting galls of Cynipidae in Jordan
2008
Twenty-three species of Chalcidoidea (5 Eurytomidae, 4 Torymidae, 2 Ormyridae, 5 Pteromalidae and 7 Eulophidae) are recorded as regular members of the parasitoid fauna inhabiting galls of Cynipidae in Jordan. The occurrence of three additional species, probably only facultatively associated with cynipid galls, is noted. Twenty-two out of the total 26 species were previously unrecorded in the country, while 13 of them are also new for the entire Middle East. Eighteen new host records were detected, together with 24 new plant-parasitoid associations. The biology of each species is briefly commented upon, as well as the presence of a host-related colour variation in some species.
Host chemical footprints induce host sex discrimination ability in egg parasitoids
2013
Trissolcus egg parasitoids, when perceiving the chemical footprints left on a substrate by pentatomid host bugs, adopt a motivated searching behaviour characterized by longer searching time on patches were signals are present. Once in contact with host chemical footprints, Trissolcus wasps search longer on traces left by associated hosts rather than non-associated species, and, in the former case, they search longer on traces left by females than males. Based on these evidences, we hypothesized that only associated hosts induce the ability to discriminate host sex in wasps. To test this hypothesis we investigated the ability of Trissolcus basalis, T. brochymenae, and Trissolcus sp. to disti…