Mating system of Bracon hebetor (Hymenoptera: Braconidae)

Abstract.

• 1 We report on the mating system of a field population of the parasitic wasp, Bracon hebetor, on a corn pile infested by the Indian meal moth, Plodia interpunctella. We demonstrate that the mating system is based upon male scramble competition polygyny with male aggregations on high places on the corn.
• 2 The sex ratio among adults was greater than 80% males on the surface of the corn, whereas below the surface the sex ratio was less than 45%. Males actively courted females on the surface, but there were no aggressive interactions among males during courtship or mating.
• 3 Approximately 20% of the females found on the surface of the corn had no sperm in their spermathecae, regardless of age, but the numbers of unmated females decreased later during the day.
• 4 In laboratory studies we showed that females from this population oviposit a female biassed sex ratio, and that only 14% of females were mated before dispersing from their place of emergence.
• 5 Thus sib-mating is unlikely in this gregarious parasitoid. This outcrossing mating system probably arose because of severe inbreeding depression that B.hebetor suffers via a sex locus: diploids that are heterozygous at the sex locus develop into females, but homozygous diploids are male and are generally inviable. The female biassed sex ratio may have evolved in B. hebetor in response to males being the more expensive sex, females dispersing more frequently from the population than males, or a fraction of females remaining unmated in the population.

     

Three new species of Sesioctonus Viereck (Hymenoptera, Braconidae, Agathidinae) from Peru

Three new species of Sesioctonus (Braconidae: Agathidinae) are described and illustrated, i.e., Sesioctonus huggerti, Sesioctonus wayquecha, and Sesioctonus bina. Two new Peruvian species records for Sesioctonus are reported: Sesioctonus longinoi and Sesioctonus diazi. A revised key to all known species of Sesioctonus is presented.     

Non-target host risk assessment of the idiobiont parasitoid Bracon celer (Hymenoptera: Braconidae) for biological control of olive fruit fly in California

Non-target risk posed by an African parasitoid, Bracon celer Szépligeti (Hymenoptera: Braconidae), was assessed for a classical biological control program against olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae: Dacinae), in California, USA. Behavioral and reproductive responses to non-target tephritid species were tested with beneficial (Chaetorellia succinea [Costa] and Parafreutreta regalis Munro) (Tephritidae: Tephritinae) and native (Rhagoletis fausta [Osten Sacken]) (Tephritidae: Trypetinae) fruit fly species in successive no-choice and choice experiments under close confinement in quarantine. Non-target host-plant substrates exposed to B. celer were yellow-starthistle flower heads containing C. succinea, Cape ivy stem galls containing P. regalis, and bitter-cherry fruit containing R. fausta. The parasitoid probed all three infested non-target plant substrates, but significantly less than olives infested with B. oleae. It produced offspring from P. regalis in Cape ivy stem galls, but appeared unable to penetrate yellow-starthistle flower heads with its ovipositor. Bracon celer killed some B. oleae and R. fausta larvae without parasitism. Reproduction on P. regalis indicates that B. celer has a broad physiological host range, which, combined with the parasitoid's acceptance of all three host-plant substrates, indicates a strong potential to negatively impact non-target species. Although physical and temporal barriers to host attack may reduce risk to most non-target tephritids by B. celer in California, the parasitoid should not be released due to its risk of harming the beneficial P. regalis. Release of P. regalis is still under consideration, however, and final risk assessment should depend on whether the fly proves useful for weed control.     

Population dynamics of the West Indian sweetpotato weevil Euscepes postfasciatus (Fairmaire): a simulation analysis

The West Indian sweetpotato weevil Euscepes postfasciatus (Fairmaire) is a major pest of the sweet potato Ipomoea batatas (L.) Lam. and this weevil is a target of an eradication program using the Sterile Insect Technique in Okinawa Prefecture, Japan. Understanding the population ecology is essential in the planning of an eradication program; hence, a host‐plant infestation survey and light trap survey have been conducted to monitor the population dynamics of the weevil on Kume Island (Okinawa Prefecture), which is the target area of the trial weevil eradication project. Seasonal tendencies of weevil density were found in these field surveys, but the tendency found in the host‐plant infestation survey was not seen every year, and the effectiveness of the light trap is somewhat suspect. To confirm the reliability of the tendency observed in these field surveys, the present study attempted to explain the tendency by a seasonal temperature change using a temperature‐based model of weevil population dynamics. The seasonal changes of weevil density differed according to host plants and host‐plant fields. The seasonal changes of weevil density inside the host plant Ipomoea indica and outside the host plants in I. indica fields were consistent with those predicted by the model. However, those inside the host plant Ipomoea pes‐caprae in the host‐plant infestation survey were contrary to the predicted ones, and those observed outside host plants in I. pes‐caprae fields by the light trap survey were not in good agreement with the predicted ones. It was concluded that the seasonal change of the weevil density observed in I. indica and I. indica fields can be explained by a seasonal temperature change, but factors other than seasonal temperature change are needed to explain those in I. pes‐caprae and I. pes‐caprae fields.     

Discovery of the genus Suhpalacsa Lefèbvre (Neuroptera: Ascalaphidae: Ascalaphinae) in Japan, with description of a new species

Suhpalacsa iriomotensis sp. nov. (Neuroptera: Ascalaphidae: Ascalaphinae), is described from Iriomotejima Island, Japan. This new species can be easily distinguished from other species of the genus by the unique ventrolateral prominences of the male ectoproct. This is the first record of the genus Suhpalacsa from Japan. The morphology of the male ectoproct and the monophyly of Suhpalacsa are discussed briefly.     

First record of the genus Wilkinsonellus (Hymenoptera,Braconidae, Microgastrinae) from Fiji with description of three new species

Wilkinsonellus Mason is a relatively small Pantropical genus of braconid parasitoid wasps within the subfamily Microgastrinae. Most of the currently described species are from the Palaeotropics; however, previous records were absent from Fiji. Here, the first three Wilkinsonellus species from Fiji are described: Wilkinsonellus corpustriacolor sp. n., Wilkinsonellus fijienis sp. n. and Wilkinsonellus nescalpura sp. n. The material was collected by Malaise traps set up in a quite variety of ecosystems (wet zone, dry zone and coastal forests) throughout the archipelago. With these records, Fiji represents the easternmost known distribution of the genus in the Indo-Pacific Region. A key to all of the currently known Wilkinsonellus species is included to facilitate species identification.     

断脉茧蜂属一新种(膜翅目:茧蜂科)

本报道了采自云南的断脉茧蜂属Heterospilus Haliday一新种：短颊断脉茧蜂Heterospilus breviatus Shi,Yang et Chen,sp nov.,模式标本保存于福建农林大学益虫研究室。     

齿背茧蜂属一新种(膜翅目:茧蜂科)(英文)

本文报道了采自云南的齿背茧蜂属 Acanthormius Ashmead一新种 :双色齿背茧蜂 A.bicolor sp.nov.。模式标本保存于福建农业大学益虫研究室     

First record of Alysia alticola Ashmead (Hymenoptera: Braconidae) in the Neotropical region

Alysia alticola Ashmead, 1890, is recorded for the first time in central Argentina, reared from pig carcasses. This is also the first mention of the genus Alysia Latreille, 1804, in Argentina, which represents the southernmost record in the Neotropical region.     

The weedy species of Merretnia (Convolvulaceae) occurring in the Solomon Islands and a description of a new species

The genus Merremia is found in the tropical regions of both hemispheres. The climbing species with fast growth rates can become troublesome weeds of cultivation and forestry. Serveral Merremia species have become serious weeds of forestry plantations in the Solomon Islands. The important species are discussed and a new species, Merremia bracteata , found in Merremia infestations is described.     

中国绒茧蜂属Apanteles Foerster一新种(膜翅目:茧蜂科)

本文报道采自中国福建的茧蜂科Braconidae小腹茧蜂亚科Microgastrinae绒茧蜂属Apanteles Foerster一新种,即透翅绒茧蜂Apanteles pellucipterus Song et Chen,sp.nov.。模式标本存放于福建农林大学植保学院益虫室。     

橘小实蝇寄生蜂切割潜蝇茧蜂的人工繁殖技术

切割潜蝇茧蜂[Psyttalia incisi(S ilvestri)]是福建疫区寄生于橘小实蝇[Bactrocera dorsalis(Hendel)]幼虫—蛹期的重要本地寄生蜂。利用室内大量繁殖的橘小实蝇幼虫作为寄主,在室内条件下对其进行人工繁殖技术研究,并设计了人工繁蜂的质量控制和工艺流程。旨在将来提供足够数量的寄生蜂来满足田间放蜂的需要,尽早实现对橘小实蝇的持续、有效地治理。     

中国印度茧蜂属Indiopius Fischer一新种(膜翅目:茧蜂科)

本文记述了茧蜂科Braconidae潜蝇茧蜂亚科Opiinae印度茧蜂属Indiopius的1个新种：Indiopius alutacius Weng et Chen sp.nov.。这是该属在中国分布的首次记录。建立了世界已知3种的分种检索表。本新种与矮茧蜂I.humillimus Fischer相似,但新种可以由下列特征予以区别：1.并胸腹节革质纹,后缘具短纵脊;2.第1腹节背板长为宽的1.2-1.3倍;3.腹板侧泡明显具齿。模式标本保存于福建农林大学益虫研究室。     

The effect of mass‐rearing on death‐feigning behaviour in the sweet potato weevil (Coleoptera: Brentidae)

The aim of our study was to examine the effect of mass‐rearing, in which there is no exposure to predators, on antipredator traits of insects for improving sterile insect technique programs. The duration of death‐feigning (antipredator behaviour) in sweet potato weevil Cylas formicarius (Summers) (Coleoptera: Brentidae) after mass‐rearing for 71 generations were compared with those in wild strain. There was no significant difference in the duration of death‐feigning between wild and mass‐reared strains. This indicated that the death‐feigning behaviour of mass‐reared strain was maintained for 71 generations even in the absence of predators. We discuss the reasons why death‐feigning behaviour is maintained after mass‐rearing.     

A new rod-shaped virus from parasitic wasp Diachasmimorpha longicaudata (Hymenoptera: Braconidae)

A new rod-shaped nucleocapsids (NCs) was found inadvertently in Diachasmimorpha longicaudata accessory gland filaments (AGFs). The NCs were 30 nm in diameter and nearly 900 nm in length. They replicated in a small cell type of the AGFs in D. longicaudata, and following oviposition, invaded and proliferated in the hemocytes of a parasitized host Bactrocera dorsalis Hendel. This finding of a completely new virus in the AGF indicate that different geographical populations (subspecies) of D. longicaudata may carry different sybionts. This is the first report showing that the same wasp species, but from a different geographical populations, can carry an entirely different virus.     

The influence of humidity on emergence in Dacnusa sibirica Telenga (Hymenoptera: Braconidae)

The effects of four humidities (33, 55, 76 and 93% relative humidity) and four ages (0–1, 2–3, 4–5, 6–7 days) of parasitized Chromatomyia syngenesiae puparia on adult emergence in the leafminer parasitoid Dacnusa sibirica were examined in the laboratory. Parasitized puparia harvested at 0–1 days were susceptible to low humidities resulting in a significantly reduced parasitoid emergence. Aging of the puparia appeared to protect the developing parasitoid from low humidities. Increasing humidity produced a corresponding increase in the longevity of the adult parasitoid.     

中国侧沟茧蜂属一新种(膜翅目:茧蜂科:小腹茧蜂亚科)

本记述从寄主斜纹夜蛾饲养得到的侧沟茧蜂属Microplitls Forster 1新种：双斑侧沟茧蜂Microplitis bicoloratus Chert,sp．nov．。模式标本保存于福建农林大学植保学院益虫室。     

A new species of Parapanteles Ashmead, 1900 (Hymenoptera: Braconidae: Microgastrinae) parasitic on Charaxes athamas (Drury) (Lepidoptera: Nymphalidae) in India

A new species of gregarious endoparasitoid, Parapanteles athamasae n. sp. (Hymenoptera: Braconidae), parasitising caterpillars of Charaxes athamas (Drury) (Lepidoptera: Nymphalidae) on the host plant Senegalia catechu (=Acacia catechu) (L.f.) Hurter & Mabb., is described from Maharashtra, India. Diagnostic characters of the new species include: propodeum with areola 0.93× longer than wide, legs yellow, hind tibia 4.30× as long as ovipositor, ovipositor sheaths exerted, first metasomal tergal plate 1.24× longer than wide, with coarse sculpture merging with longitudinal striations at 3/4 of the apical region. This is the first time a species of the family Nymphalidae Rafinesque is recorded in association with Parapanteles Ashmead, 1900. A key to the Indian species of Parapanteles based on females is also provided.     

A review of the West Palaearctic aphidiines (Hymenoptera: Braconidae: Aphidiinae) parasitic on Uroleucon spp., with the description of a new species

A review of aphidiine wasps (Hymenoptera: Braconidae) parasitizing the Uroleucon species in the West Palaearctic is presented. Eleven species are keyed and illustrated. In addition, a new hymenopteran parasitoid species: Praon nonveilleri n. sp. from Uroleucon inulicola (Hille Ris Lambers) infesting Inula ensifolia L., is described. The new species is diagnosed and illustrated. It belongs to the “dorsale-yomenaé” species group and was collected from the Djetinja canyon in Serbia and Montenegro. The aphidiines presented in this work were identified from 97 aphid taxons occurring on 236 plant taxons. Furthermore, 361 original parasitoid – host aphid – host plant associations of the species mentioned in the key are presented. Finally, phylogenetic relationships inside the “dorsale-yomenae” species group and related species were reconstructed using cladistic distance methods.