Development and morphological characterization of the immature stages of Tetrastichus giffardianus Silvestri (Hymenoptera: Eulophidae)

The gregarious endoparasitoid Tetrastichus giffardianus Silvestri (Hymenoptera: Eulophidae) is a natural enemy of fruit flies. This parasitoid was previously used to successfully control Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in Hawaii, USA. Despite its importance in the control of fruit fly pests, little is known about the development or characteristics of its preimaginal stages. The aim of this study was to observe the development and morphologically characterize the immature stages of Tetrastichus giffardianus. Tetrastichus giffardianus individuals were reared on C. capitata larvae/pupae under laboratory conditions at a temperature of 25 ± 2 °C, relative humidity of 60 ± 10%, and 12-h photophase. Third-instar C. capitata larvae were exposed to parasitism for 24 h. After parasitism, the pupae were dissected every 24 h to evaluate the stage of development attained by T. giffardianus, and to record their morphological characteristics. A stereomicroscope was used to observe all the immature stages of T. giffardianus. The complete development of T. giffardianus under these conditions was completed within 14 days as follows: egg (duration ? 1 day); first (? 1 day), second (? 1 day), and third (? 2 days) larval instars; pre-pupa (? 2 days); and pupa (? 7 days). The immature stages of T. giffardianus differed sufficiently in their shape, color, and size to allow morphological characterization.     

Identification of 21 polymorphic microsatellites in the African parasitoid wasp, Psyttalia lounsburyi (Silvestri) (Hymenoptera: Braconidae)

We have developed 21 dinucleotide repeat microsatellite loci from African populations of Psyttalia lounsburyi (Silvestri) (Hymenoptera: Braconidae), a parasitoid wasp of the olive fruit fly, as part of a study assessing the role of introgression/hybridization in the success of a biological control introduction. We proposed suitable conditions for polymerase chain reaction multiplexing. All 21 loci were polymorphic with two to 21 alleles per locus within the Kenyan and South African populations tested. Most of them were successfully amplified in two other Psyttalia species.     

Selection of non‐target tephritids for risk evaluation in classical biocontrol programmes against the olive fruit fly

The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is the key pest of olives (Olea europaea L.). Classical biological control against this insect was previously attempted in Spain with Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae), with very limited success. Other parasitoids are now available for new classical biological control programmes. Before release of exotic parasitoids, an assessment of their potential impact on non‐target species is required. Surveys were conducted in different olive groves in south‐eastern Madrid to study wild tephritids associated with Asteraceae plants. We recorded plant species and their abundance and collected flower heads to identify and quantify tephritid species. Fruits from Rosa canina L. were also collected. After a multicriteria analysis (MCA), we propose Urophora hispanica Strobl, U. stylata (Fabricius) and Carpomya schineri (Loew) as candidates for further risk assessment experiments. Additional information on new associations between tephritid flies and Asteraceae plants and on autochthonous Hymenoptera parasitizing tephritids is provided.     

Natural establishment of a parasitoid complex on Bactrocera latifrons (Diptera: Tephritidae) in Hawaii

Bactrocera latifrons (Hendel) (Diptera: Tephritidae) is the most recent of four tephritid fruit fly species accidentally introduced into Hawaii. Although parasitoids have been released against other tephritid fruit fly species and have shown partial success in Hawaii, no parasitoids were released until 2004 to suppress populations of B. latifrons. The present study was conducted to document the parasitoid complex that has naturally established against B. latifrons in Hawaii and to assess whether there is a need for improving the biological control of this species. Based on ripe turkeyberry (Solanum torvum Sw) fruit collections over three consecutive years B. latifrons was the dominant tephritid fruit fly infestating turkeyberry at all four sites surveyed, across three major islands in Hawaii. The overall percentage parasitism of B. latifrons ranged from a low of 0.8% (Hana, Maui) to a high of 8.8% (Kahaluu, Oahu). Five primary parasitoid species were recovered from individually held B. latifrons puparia: Fopius arisanus (Sonan), Psyttalia incisi (Silvestri), Diachasmimorpha longicaudata (Ashmead), D. tryoni (Cameron), and Tetrastichus giffardianus Silvestri. F. arisanus was the predominant parasitoid at three of the four sites. Low levels of parasitism suggest that there is a need to improve biological control of B. latifrons, to minimize chances of this species causing economic impacts on crop production in Hawaii. We discuss the possibility of improving biological control of B. latifrons through augmentative releases of F. arisanus or introduction and release of specific and efficient new parasitoid species.     

A survey of fruit-feeding insects and their parasitoids occurring on wild olives,Olea europaea ssp. cuspidata,in the Eastern Cape of South Africa

Fruits of wild olives, Olea europaea ssp. cuspidata (Wall. ex G. Don) Cif., were collected in the Eastern Cape, South Africa, during 2003–2005 to quantify levels of fruit-infesting pests and their parasitoids. Two species of Tephritidae, Bactrocera oleae (Rossi) and B. biguttula (Bezzi), were the most abundant insects recovered and were reared from most samples. Fruit infestation rates by the Bactrocera spp. were generally below 8% and over half of the infestations were under 1%. When parasitism occurred in samples with flies, levels ranged from 7 to 83%. Several species of opiine braconid wasps, Psyttalia concolor (Szépligeti), Psyttalia lounsburyi (Silvestri), and Utetes africanus (Szépligeti) and one braconine wasp, Bracon celer Szépligeti, were reared from fruits containing B. oleae and/or B. biguttula. Chalcidoid parasitoids and seed wasps included seven species of Eurytomidae (Eurytoma oleae, Eurytoma sp., and Sycophila sp.), Ormyridae (Ormyrus sp.), Torymidae (Megastigmus sp.), and Eupelmidae (Eupelmus afer and E. spermophilus). One species of moth, Palpita unionalis (Hübner) (Crambidae), was recovered in very low numbers and without parasitoids. The survey results indicate that fruit flies might not become economic pests of the nascent commercial olive industry in the Eastern Cape, and the small numbers present may be controlled to a considerable level by natural enemies.     

Comparative evaluation of two olive fruit fly parasitoids under varying abiotic conditions

Psyttalia lounsburyi (Silvestri) and P. humilis (Silvestri) (Hymenoptera: Braconidae) were evaluated in California for their potential to control the invasive olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae). Psyttalia lounsburyi is a specialist on B. oleae while P. humilis also attacks other tephritid species. Field cage trials, conducted from 2006 to 2009, were used to compare P. lounsburyi and two populations of P. humilis (Kenya and Namibia) in California’s interior valley and coastal regions. Both parasitoid species reproduced on B. oleae in all trials. Under similar abiotic conditions, offspring production per female was higher in P. humilis than in P. lounsburyi, suggesting that host specificity by P. lounsburyi does not confer a higher efficiency on B. oleae in cultivated olives. Two abiotic factors were shown to impact parasitoid efficiency. First, adult parasitoid survival was poor during periods of high summer temperatures, common to the olive production areas in California’s interior valleys. Second, parasitism levels were lower on B. oleae larvae feeding in larger Ascolano cv. fruit than in smaller Manzanillo cv. fruit. Results are discussed relative to biological control of B. oleae in commercial olives and the usefulness of natural enemies specialized to attack fruit flies in wild olives compared with the larger cultivated olive fruit.     

Diversity and abundance of insect visitors to flowers of trees and shrubs in a South African savannah

This study presents the results of a landscape‐scale survey for insect floral visitors in the Skukuza Ranger District, Kruger National Park, South Africa. Floral visitors were sampled from flowering trees and shrubs along linear transects spanning the entire district. Six plant species were sampled in the late dry season (Acacia grandicornuta Gerstner, A. nigrescens Oliver, Cassia abbreviata Oliver, Combretum hereroense Schinz, Combretum zeyheri Sonder, Euclea divonorum Hiern), and eleven plant species were sampled during the rainy season (Acacia exuvialis Verdcourt, A. grandicornuta Gerstner, A. nilotica (L.) Willdenow, A. tortilis (Forsskal) Hayne, Dichrostachys cinerea Miquel, Flueggea virosa (Roxburgh) Baillon, Grewia bicolor Jussieu, G. flava De Candolle, G. flavescens Jussieu, G. monticola Sonder, and Peltophorum africanum Sonder). Coleoptera, Hymenoptera and Lepidoptera comprised the majority of floral visitors, while species of Blattodea, Diptera, Hemiptera and Neuroptera also occurred on flowers. Known or likely pollinators include bees (Hymenoptera: Apidae, Halictidae and Megachilidae) and scarab beetles (Coleoptera: Scarabaeidae). These plant species appear to have generalist pollination systems, with the exception of species of Grewia L., which appear to be pollinated primarily by bees. A provisional plant–pollinator food web is presented for the eleven species of trees and shrubs which flower during the rainy season.     

Evaluation of Fopius arisanus as a biological control agent for the olive fruit fly in California

1 The egg‐prepupal parasitoid Fopius arisanus (Hymenoptera: Braconidae) was evaluated in quarantine facilities as a potential biological control agent for the olive fruit fly Bactrocera oleae (Diptera: Tephritidae) in California, U.S.A. 2 Nontarget testing of two weed biological control agents confirmed that F. arisanus will not attack Tephritidae that feed in inflorescences or galls. It may, however, pose risks to native Tephritidae that feed in fruit. 3 Females preferentially oviposited in eggs, although first‐instar B. oleae were also attacked. Low lifetime reproductive potential and high rates of direct mortality inflicted on host eggs indicate that rearing on B. oleae may prove difficult. 4 In multiparasitized B. oleae, F. arisanus prevailed in competition against two species of larval–pupal parasitoids, Diachasmimorpha kraussii and Psyttalia concolor (both Hymenoptera: Braconidae). 5 The broad host‐range of F. arisanus with respect to fruit‐feeding Tephritidae may preclude its introduction to California, as may its low fecundity and its intrinsic competitive superiority over larva l–pupal parasitoids, which include specialists on B. oleae that are currently being introduced to California. High rates of direct mortality, however, point to potential uses in augmentative biological control. Whether or not F. arisanus is released in California, its biology as a parasitoid of B. oleae has been little studied to date and the results herein may be applied in other regions worldwide where B. oleae is a problem.     

Do Psyttalia concolor (Hymenoptera: Braconidae) males gain in mating competitiveness from being courted by other males while still young?

The role of male–male courtship in parasitic wasps is not well understood and nothing has been reported on the implication of learning in regard to homosexual behavior in hymenopteran parasitoids. In Psyttalia concolor (Hymenoptera: Braconidae), a synovigenic koinobiont larval–pupal endoparasitoid of many Diptera Tephritidae of economic importance, courtship and mating attempts are frequently displayed among males. Here we determine whether P. concolor males that are courted while still young by sexually mature males can compete better with other males when they court females. The results showed that P. concolor immature males do not appear to gain from receiving male courtship, but they develop a higher intensity (more wing fanning and shorter latency time) in the successive courtship of the females. The hypothesis that, under some conditions, such higher courtship intensities may increase the probability of gaining a mating advantage is discussed.     

Longevity costs of same‐sex interactions: first evidence from a parasitic wasp

Costs of sexual interactions play a key role in life‐history evolution. Although the costs of reproduction have been investigated in both sexes of many insects, the costs of same‐sex interactions have been examined in few species. In parasitic wasps, very little has been reported about the longevity costs of heterosexual interactions, and nothing is known about longevity costs of same‐sex interactions. In this study, the effects of heterosexual and homosexual activities on longevity were evaluated in Psyttalia concolor (Hymenoptera: Braconidae), a synovigenic koinobiont larval‐pupal endoparasitoid of tephritid flies. When compared with individually housed virgin wasps, male longevity was strongly reduced both in males kept with females, and in males kept with other males. When females were kept with males, their longevity was reduced compared with the virgin females and females kept with other females. Overall, the costs of male–female interactions were considerable in both sexes of P. concolor, while same‐sex activities were found to be costly only among males, suggesting that they may have implications for the evolution of the P. concolor mating system.     

The production of floral oils byMonttea (Scrophulariaceae) and the function of tarsal pads inCentris bees

Plant species that secrete oil as their primary floral reward are rare and sporadically found in the angiosperms. We report here thatMonttea, a genus previously unsuspected of being an oil-plant, produces lipids from trichome elaiophores on the inside of the lower (anterior) lip. The discovery of the production of oils by species of this S. American genus explains the occurrence of unusual dual-function collecting structures in ArgentineCentris (Hymenoptera: Anthophoridae) and explains the presence of oil-collecting bees in regions where oil-secreting flowers were previously thought to be absent. The behavior of these centridine pollinators onMonttea flowers parallels that of oil-collecting bees onDiascia (Scrophulariaceae) in S. Africa.     

Molecular characterization of <Emphasis Type="Italic">Psyttalia lounsburyi</Emphasis>, a candidate biocontrol agent of the olive fruit fly,and its <Emphasis Type="Italic">Wolbachia</Emphasis> symbionts as a pre-requisite for future intraspecific hybridization

Numerous arthropod species are genetically differentiated across their distribution area. Diversifying the geographical origins of a biocontrol agent species can be used to favour their perennial establishment by the sampling of pre-adapted genotypes and/or the production of new genotypes through hybridization. Hybridization can be nevertheless challenged by reproductive isolations induced by some common microbial endosymbionts. In this study, we aimed at characterizing (i) the genetic diversity of six populations of Psyttalia lounsburyi (Hymenoptera: Braconidae), a candidate biocontrol agent of the olive fruit fly Bactrocera oleae (Diptera: Tephritidae) and (ii) the diversity of their Wolbachia endosymbionts. Both mitochondrial and microsatellite markers evidence clustering between the South African population and several Kenyan/Namibian populations. The survey of the Wolbachia also distinguished two main variants with a spatial heterogeneity in the infection status. All these results are discussed in the context of the use of these P. lounsburyi populations for hybridization and further field releases.     

Release and establishment of Cotesia flavipes Cameron (Hymenoptera: Braconidae) an exotic parasitoid of Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) in East and Southern Africa

Cotesia flavipes Cameron (Hymenoptera: Braconidae) was first imported into Kenya in 1991 from Pakistan for control of Chilo partellus (Swinhoe) (Lepidoptera: Crambidae). First releases were made at the Kenya coast in 1993 and a few recoveries of the parasitoid were made the following year. Additional foreign exploration for C. flavipes was conducted in central India in 1996 and 1998, which resulted in additional importation of the parasitoid for subsequent releases in eastern and southern Africa. Region-wide releases commenced with releases in Mozambique in 1996, Somalia in 1997 and Uganda in 1998. By 2005, many releases had been made in 10 countries in East and Southern Africa with establishment being reported in all of them except Eritrea but including Ethiopia where releases had never been made. This paper describes the progress made in the release and establishment of C. flavipes in East and Southern Africa and quantifies the rate of spread from the initial release sites in Kenya.     

Eucharitid Parasitism of the Neotropical Ant Ectatomma tuberculatum: Parasitoid Co‐occurrence,Seasonal Variation,and Multiparasitism1

Multiparasitism is reported for the first time in Eucharitidae (Hymenoptera: Chalcidoidea). Dilocantha lachaudii, Isomerala coronata, and Kapala sp. were found simultaneously attacking the same population of Ectatomma tuberculatum (Olivier) (Hymenoptera: Formicidae: Ectatomminae) in southern Mexico. Adults of D. lachaudii and I. coronata completed development on the same individual host on three occasions. The genus Kapala is reported for the first time as a parasitoid of E. tuberculatum, and I. coronata is reported in Mexico for the first time.     

Hymenopteran parasitoids and dipteran predators of <Emphasis Type="Italic">Diuraphis noxia</Emphasis> in the west-central Great Plains of North America: Species records and geographic range

Parasitoids and predatory flies were sampled in the wheat production region of the west-central Great Plains (southeastern Wyoming, western Nebraska, and north-central Colorado) of North America using plant material infested with the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae). Samples were taken April through October in 2001 and 2002, which was 15–16 years after first detection of D. noxia and 5–6 years after the last release of natural enemies for its control in this region. The natural enemies detected were (in order of high to low detection frequencies across three states and 2 years): Aphelinus albipodus Hayat and Fatima (Hymenoptera: Aphelinidae), Eupeodes volucris Osten Sacken (Diptera: Syrphidae), Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae, Aphidiinae), Leucopis gaimarii Tanasijtshuk (Diptera: Chamaemyiidae), Aphidius avenaphis (Fitch), Aphidius matricariae Haliday, Diaeretiella rapae (MIntosh), Aphidius ervi Haliday, Praon yakimanum Pike and Starý (Hymenoptera: Braconidae, Aphidiinae), and Aphelinus asychis Walker (Hymenoptera: Aphelinidae). The results confirmed establishment of one of the 10 exotic parasitoid species released for D. noxia control (A. albipodus) in the west-central Great Plains. It is unknown whether detection of A. asychis, A. matricariae, and D. rapae can be attributed to exotic introductions or preexisting populations. Other species detected in this study have been previously documented from the western US, although the recognized distributions have expanded for A. avenaphis, L. gaimarii, and P. yakimanum compared to the first few years after initial detection of D. noxia. Thus, there is definitive establishment of one exotic introduced for D. noxia and considerable range expansion of preexisting species that prey upon D. noxia.     

Preliminary inventory of parasitoids associated with fruit flies in mangoes,guavas, cashew pepper and wild fruit crops in Benin

Fruit flies are pests of great economic importance due to their quarantine pest status and losses recorded in West Africa. An inventory of parasitoids associated with fruit flies in mangoes, guavas, cashew, pepper and major wild fruit crops was carried out in northern-central Benin in 2005, 2006, and 2008. Tephritid parasitoids reared from field-collected fruits belonged to three families: Braconidae (97.2%), Eulophidae (1.6%) and Pteromalidae (1.2%). Fopius caudatus (Szépligeti) accounted for 73.8% of all the parasitoids and therefore was the most abundant and widely distributed parasitoid. The parasitism rate was 7.7%, with the highest recorded in wild fruit crop habitat. Ceratitis cosyra (Walker) (77%) was the fly host most commonly reared from fruits that produced F. caudatus. The recently introduced pest Bactrocera invadens Drew Tsuruta and White was rarely parasitized and only by Pachycrepoideus vindemmiae (Rondani) (Hymenoptera: Pteromalidae) at this time. This is the first report of the inventory of one native parasitoid species from B. invadens in Africa, especially in West Africa.     

Assessment of the impact of natural enemies on stemborer infestations and yield loss in maize using selected insecticides in Mozambique

The effect of natural enemies on stemborer infestations and maize grain yields was estimated using an insecticide exclusion method. Field experiments were conducted at low, mid and high elevation zones, which vary in the stemborer species composition. Dimethoate was applied to exclude natural enemies and Cypermethrin to suppress stemborers, while other plots served as control. At all study sites more stemborer larvae and pupae were collected when natural enemies were excluded. Parasitism as well as maize grain weight in the unprotected plots were significantly higher than in the exclusion plots. Yield losses increased by 28.9 % in unprotected to 43.3 % in exclusion plots. The most abundant parasitoids of Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) were Cotesia sesamiae (Cameron), Cotesia flavipes Cameron (Hymenoptera: Braconidae) and Dentichasmias busseolae Heinrich (Hymenoptera: Ichneumonidae). While for Busseola fusca (Fuller) (Lepidoptera: Noctuidae) they were C. sesamiae, Sturmiopsis parasitica (Curran) (Diptera: Tachinidae) and Porcerochasmias nigromaculatus Heinrich (Hymenoptera: Ichneumonidae). It was concluded that exclusion of natural enemies caused an increase in stemborer populations, thus, the parasitoids play an important role in suppressing stemborer infestations and increase maize yield.     

Mammal distributions in the western Mediterranean: the role of human intervention

The natural distribution of the 17 non-flying mammal species occurring wild in both the Maghreb (north-west Africa) and Iberia (south-west Europe) is considered. It is concluded that only four species – Red Fox Vulpes vulpes, Wild Boar Sus scrofa, Wild Cat Felis silvestris and Otter Lutra lutra – are native to both regions, while another three – Red Deer Cervus elaphus, Brown Bear Ursus arctos and Aurochs Bos primigenius – were native to North Africa until the mid-Holocene but have probably died out naturally. Algerian Hedgehog Atelerix algirus, Barbary Ape Macaca sylvanus, Genet Genetta genetta and Egyptian Mongoose Herpestes ichneumon are widely accepted as introductions to Europe from North Africa. The remaining six species, and Red Deer now found in Africa, were also probably introduced – Rabbit Oryctolagus cuniculus, Weasel Mustela nivalis, Wood Mouse Apodemus sylvaticus and Lesser White-toothed Shrew Crocidura russula from Europe to Africa; Algerian Mouse Mus spretus from Africa to Europe; Savi’s Pygmy Shrew Suncus etruscus perhaps from the eastern Mediterranean to both Iberia and the Maghreb. There are two Maghrebi species which, although not found in Europe, are more closely related to Palaearctic than to Afrotropical species: Garden Dormouse Eliomys melanurus, probably native to north-west Africa, although possible augmentation of the natural population cannot be ruled out, and Whitaker’s Shrew Crocidura whitakeri, a North African endemic. Removal of so many species of European provenance from the list of mammals native to north-west Africa should not be considered to weaken its position as part of the Palaearctic zoogeographical region. Bats and other, non-mammalian, taxa illustrate the clear faunal relationship between the Maghreb and south-west Europe, whilst emphasizing its distinction from subsaharan Africa.     

Response of Three Hymenopteran Parasitoids Introduced for Fruit Fly Control to a Gall-Forming Tephritid,Procecidochares alani(Diptera: Tephritidae)

The response of three larval–pupal parasitoids,Diachasmimorpha longicaudata(Ashmead),Diachasmimorpha tryoni(Cameron), andTetrastichus giffardianusSilvestri, to the Hamakua pamakani gall fly,Procecidochares alaniL., was determined in the laboratory. We also observed responses of these parasitoids to their normal rearing hosts,Bactrocera dorsalis(Hendel) andCeratitis capitata(Weidemann).D. tryonilanded on pamakani galls or on dishes containingP. alanilarvae as frequently as on dishes containingC. capitata.In contrast,D. longicaudataonly rarely landed on the galls.D. tryoniandD. longicaudataoviposited in galls in fewer than 1% of our observations.D. longicaudataprobedP. alanilarvae as frequently asB. dorsalislarvae, but no parasitoid offspring were observed.D. tryonioviposited more frequently inC. capitatathanP. alani.NoD. tryonideveloped inP. alanilarvae.T. giffardianuslanded on pamakani galls andP. alanilarvae more frequently than any other host substrate. In contrast,T. giffardianusentered galls with artificially opened windows one time in 10 observations. We observed 12% parasitism ofP. alanilarvae dissected from the galls and 20% of parasitismP. alaniin the windowed galls. We discuss the implications of our results for future augmentative or classical biological control studies.