Host preferences ofTrichogrammatoidea bactrae fumata (Hym.: Trichogrammatidae) an egg parasitoid of leafrollers (Lep.: Tortricidae)

Trichogrammatoidea bactrae fumata Nagaraja is a naturally occurring egg parasitoid of some leafrollers in New Zealand kiwifruit orchards. The parasitoid showed a distinct preference for younger host-eggs ofEpiphyas postvittana, in which it achieved a higher rate of successful development. Such a preference is not as apparent withCtenopseustis obliquana. Host-species preference experiments found that the parasitoid rarely attackedPlanotortrix octo, and successful wasp emergence from parasitised eggs of this host was low.Epiphyas postvittana was the preferred host whenT. bactrae fumata was reared on this species. When reared onC. obliquana, the parasitoid showed no preference forE. postvittana orC. obliquana.     

Temperature‐dependent development of the parasitoid Tachinaephagus zealandicus on five forensically important carrion fly species

The influences of temperature and host species on the development of the forensically important parasitoid Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae) were studied at six constant temperatures in the range of 15–30°C. T. zealandicus completed development successfully between 15°C and 27°C on five species of Calliphoridae, Calliphora albifrontalis Malloch, Calliphora dubia Macquart, Lucilia sericata Meigen, Chrysomya rufifacies Macquart and Chrysomya megacephala Fabricius. No adult parasitoids emerged from any of the host species reared at 30°C. Temperature and host species significantly influenced development time, emergence success and progeny size. Development was significantly longer on Ch. megacephala and Ch. rufifacies at 18–24°C and significantly longer on Ch. rufifacies and C. albifrontalis at 15°C and 27°C. Parasitoid emergence success was greatest at 21°C, declined at the temperature extremes (15°C and 27°C) and was significantly lower on Ch. megacephala and Ch. rufifacies than on the three other host species. Progeny numbers per host pupa were highest at 21–24°C, declined on either side of this temperature range and were significantly lower on L. sericata, Ch. rufifacies and Ch. megacephala than on either C. dubia or C. albifrontalis. An effect of host species on sex ratio was only observed at 27°C, at which a higher proportion of T. zealandicus females emerged from Ch. megacephala and Ch. rufifacies than from the other host species. The thermal requirements for development (developmental thresholds, thermal constant, optimum temperature) of T. zealandicus in each host species were estimated using linear and non‐linear models. Upper and lower developmental thresholds ranged between 29.90°C and 31.73°C, and 9.73°C and 10.08°C, respectively. The optimum temperature for development was estimated at between 25.81°C and 27.05°C. Given the significant effect of host species on development time, the use of parasitoid–host‐specific developmental data in forensic application is recommended.     

Parasitoids of the gall-forming aphidSmynthurodes betae [Aphidoidea: Fordinae] in Israel

In an ecological investigation of the gall-forming aphid,Smynthurodes betae Westw., we discovered that more than 20% of the fundatrix galls were parasitized byMonoctonia pistaciaecola Stary (Aphidiidae). This is a new host record for this parasitoid. A Pteromalid hyper-parasite was identified asPachyneuron? leucopiscida Mani. Ecological information on the parasitoid is provided, and the low frequency of parasitoids known from gall-forming aphids, compared with freeliving ones, is discussed.     

Longevity and development of the egg-parasitoid,Cheiloneurus pyrillae [Hymenoptera: Encyrtidae] at different combinations of temperature and relative humidity

Out of the 2 important physical factors like temperature and relative humidity, the former plays significant role in affecting the survival of adults and development of immature stages ofCheiloneurus pyrillae Mani which is an important egg parasitoid of the sugarcane leaf hopper (Pyrilla perpusilla Walker) in India. Average longevity of males and females of this parasitoid decreased from 2.47 to 0.81 days and from 4.95 to 0.84 days, respectively when the test temperature was increased from 15 to 35±1.5°C. Similarly, its mean developmental period was found to reduce from a maximum of 45.87 to a minimum of 10.12 days when the rearing temperature was increased from 15 to 30±1.5°C. The parasitoid could not be reared at or above 32.5±1.5°C because its immature stages failed to withstand this temperature. These informations will be helpful in maintaining the mass culture ofC. pyrillae in the laboratory.     

A method for the extraction ofSitona [Col.: Curculionidae] eggs from soil and occurrence of a mymarid [Hym.: Chalcidoidea] in the mediterranean region

A simple method of extracting the eggs ofSitona spp. from the soil is described. From 1973 to 1975 it was used in Spain, France, Italy and Greece to collect in good condition the eggs ofSitona humeralis Stephens, a weevil which has recently become a major pest in Australia. A mymarid parasitoid provisionally identified asPatasson lameerei Debauche emerged from these eggs apparently unaffected by the extraction method.     

Parasitoid hymenopterans of Costa Rica: Geographical distribution of the species associated with fruit flies [Diptera: Tephritidae]

The geographical distribution of the parasitoid species associated with fruit flies in Costa Rica is presented. In a study of 319 fruit samples infested with larvae of fruit flies, collected from 135 localities, 8 parasitoid species were recovered from 11.0% of the fruit samples. Two species are considered to be indigenous, two were introduced for the biological control ofCeratitis capitata (Wiedemann) in this country, at least 3 unidentified species of eucoiline cynipoids and one species of uncertain origin was found for the first time. The identified parasitoids were:Doryctobracon crawfordi (Viereck) (indigenous),D. areolatus (Szépligeti) (indigenous),Biosteres longicaudatus Ashmead (introduced),Aceratoneuromyia indica (Silvestri) (introduced) andTrichopria sp. (indigenous?). The introduced species were more frequently associated withAnastrepha spp. than withC. capitata. The need for systematic monitoring of populations of released parasitoid species is suggested.     

New techniques of rearingAnagrus flaveolus [Hym.: Mymaridae], an egg parasitoid of the brown planthopper

A small cage was designed to study the biology and behavior ofAnagrus flaveolus Waterhouse, an important egg parasitoid of the brown planthopper,Nilaparvata lugens (Stal), a pest of rice. A method of rearing moderate numbers of parasitoids on planthopper eggs in the laboratory was developed. Though the mymaridAnagrus flaveolus Waterhouse, a common egg parasitoid of rice planthoppers and leafhoppers all over Asia, reduces pest populations, its biological control potential has largely been overlooked because of its minute size and the lack of suitable techniques to study and rear it in the laboratory.Ôtake (1968, 1969) described some techniques to study the development, longevity and fecundity of a related speciesAnagrus nr.flaveolus Waterhouse. The cages described herein are much simpler to build and more efficient to use compared with those developed earlier. Rearing this important parasitoid in large numbers in the laboratory has not been done before.     

Studies on the bionomics ofTrioxys (Binodoxys) indicus [Hym.: Aphidiidae]: Effect of population densities on sex ratio

The effect of different population densities ofTrioxys (Binodoxys) indicus Subba Rao & Sharma and its hostAphis craccivora Koch, on the sex ratio (female: male) of the parasitoid was observed. The sex ratio (favouring female sex) increased with increase of host density. Parasitoid contamination priciple and behavioural responses of female parasitoid in addition to environmental factors were applied to explain the results. Results clearly indicated that fewer parasitoid releases might be better at any immediate release site for the production of maximum female progeny in this species.     

In vitro rearing ofOoencyrtus pityocampae [Hym., Encyrtidae], an egg parasitoid ofThaumetopoea pityocampa [Lep., Thaumetopoeidae]

Ooencyrtus pityocampae (Mercet) is a polyphagous egg parasitoid, known mainly as an egg parasitoid of the Pine Processionary Caterpillar,Thaumetopoea pityocampa (Denis &; Schiffermüller), a pest of pines in Southern Europe and in the Mediterranean region. Rearing on artificial medium was recently undertaken, and after a large screening of both materials and techniques available for this aim, a PVC film and a medium devoid of insect material were found as suitable for the complete development ofO. pityocampae. The artificial eggs allowed the parasitoid to oviposit and to develop up to the adult stage. Five adults (2 males and 3 females) were obtained. Development was slower than that observed in natural hosts. Two out of three females laid viable eggs in both natural and artificial eggs.     

New distributional and host records for the parasitoid Gronotoma adachiae (Hymenoptera: Figitidae: Eucoilinae) in Asia

The parasitoid Gronotoma adachiae is reported from Vietnam for the first time. The vegetable leaf miner Liriomyza sativae (Diptera: Agromyzidae) is a new host record. The G. adachiae specimens collected in Yunnan Province are the second record of this parasitoid from China.     

Fruit trap: A detection and collection tool for opiine parasitoids (Hym.: Braconidae) of the oriental fruit fly,Bactrocera dorsalis (Dipt.: Tephritidae)

A fruit trap was developed for detection and collection of the opiine parasitoids of the oriental fruit fly,Bactrocera (=Dacus)dorsalis (Hendel). Gravid females ofBiosteres arisanus (Sonan), an egg-larval parasitoid, orDiachasmimorpha longicaudata (Ashmead) andPsytallia incisi (Silvestri), both larval parasitoids, were lured to parasitize the eggs or larvae ofB. dorsalis inoculated in ripe papaya fruits,Carica papaya L. Progenies ofB. arisanus were consistently recovered from papaya fruits inoculated withB. dorsalis eggs (subsequently referred to as egg fruit traps). Except in Moloaa on Kauai (6%), higher percentage ofB. dorsalis parasitization (range=38–43%) was recorded in Hilo, island of Hawaii and Waimanalo and Poamoho, island of Oahu. Progenies ofD. longicaudata and a fewP. incisi were recovered from papaya fruits artificially infested withB. dorsalis larvae (subsequently referred to as larval fruit traps). The recovery of parasitoid progenies from larval fruit traps suspended from papaya trees did not differ significantly from larval fruit traps placed on the ground. In both methods of trap placement, percent parasitization ofB. dorsalis byD. longicaudata (predominant species) ranged from 58–60%. On the other hand, significantly moreB. arisanus thanD. longicaudata andP. incisi adults (larval parasitoids) were recovered from fully ripened to highly deteriorated papaya fruits collected from papaya trees or ground (fallen fruits).     

A new species of Lathrolestes (Hymenoptera,Ichneumonidae) from Ecuadorian Amazonia,with?a?key?to the Neotropical species of the genus

Here we describe and illustrate a new parasitoid wasp species, Lathrolestes gauldi sp. n. from the lowland rainforest of eastern Ecuador and provide a key to the Neotropical species of the genus. This is the first record of the subfamily Ctenopelmatinae from Ecuador.     

Phenology, population trend and natural enemies ofAleurothrixus floccosus (Hom.: Aleyrodidae) at a newly invaded area in Athens, Greece

Aleurothrixus floccosus (Homoptera: Aleyrodidae) first invaded eastern urban areas of Athens, Greece, in May 1991. At Zographou, Athens, in 1992–1994, most overwinteringA. floccosus nymphs were of the 3rd and 4th instars, and pupae; during other periods of the year, all developmental instars were found, at fluctuating rates. In 1993, peaks in the numbers of eggs laid coinciding with sharp increases in percentage of 1st instar nymphs found permitted the distinction of 6 overlapping generations. High densities ofA. floccosus infesting citrus in autumn 1992, in the range of 9.1–10.9 nymphs/cm² leaf surface, were brought under control by autumn 1993, with maximum densities of 1.1–1.7 nymphs/cm². This reduction is attributed mostly to the action of the introduced parasitoidCales noacki (Hymenoptera: Aphelinidae), released 3 km from Zographou in 1992 and at Zographou itself in 1993. No indigenous parasitoid was ever found parasitizingA. floccosus. The first record ofClitostethus arcuatus (Coleoptera: Coccinellidae) in Greece is reported. In summer 1992, eggs larvae and adults ofC. arcuatus were noticed on citrus leaves infested withA. floccosus at Zographou. From 1992 to 1994, the adults were often detected in field samplings and on yellow sticky traps. C. arcuatus adults and larvae were successfully reared, under optimal laboratory conditions, on eggs and early-instar nymphs ofA. floccosus and on eggs ofAnagasta kuehniella (Lepidoptera: Pyralidae), but the adults did not reproduce.     

Classical biological control ofaleurocanthus spiniferus (Hem.: Aleyrodidae), on citrus in Southern Africa

The spiny blackfly,Aleurocanthus spiniferus (Quaintance), is a citrus pest in parts of Mpumalanga, South Africa, and in Swaziland. The leaves, fruit and branches of infested trees are usually covered with sooty mould and a reduction in tree vigour and production is experienced. Classical biological control ofA. spiniferus by the parasitoid,Encarsia cf.Smithi (Silvestri) (Hym.: Aphelinidae) is reported with a significant reduction in numbers ofA. spiniferus. The parasitoid dispersed successfully from isolated trees growing in home gardens andA. spiniferus was virtually eliminated up to 0,8 km from the nearest point of release within 10 months. A mean of 72.9% parasitism was reached. In 8 months,E. cf.smithi statistically reduced theA. spiniferus in parts of a commercial orchard where it was released, reaching 82.4% parasitism.     

Native parasitoids associated with the genusAnastrepha (Dipt.: Tephritidae) in Los Tuxtlas,Veracruz, Mexico

In this paper we record the native parasitoids associated withAnastrepha fruit flies collected in a native tropical community from Los Tuxtlas, Veracruz, Mexico. A total of 1600 puparia ofAnastrepha were recovered from infested fruits of ten different host plants. From these puparia we obtained 218 Hymenopteran parasitoids representing the following species:Doryctobracon areolatus (Szépligeti),Utetes (Bracanastrepha) aff.anastrephae (Viereck),Doryctobracon crawfordi (Viereck),Opius hirtus (Fischer),Microcrasis n. sp.,Nealiolus n. sp. (all Braconidae);Odontosema n. sp. andLopheucoila sp. (Cynipidae). The most abundant and frequently encountered parasitoid species observed during this study wasD. areolatus, representing 59.2% of all recovered parasitoids. The analysis of different infestation rates in fruits regarding to degree of parasitization in theseAnastrepha species suggest they are not correlated, meanwhile some host plant characteristics such as fruit size, could play an important role in influencing rates of parasitization.     

Specificity and instar preference ofDiplazon laetatorius (Hym.: Ichneumonidae) parasitizing aphidophagous syrphids (Dipt.: Syrphidae)

D. laetatorius is one of the most important natural enemies of aphidophagous syrphid flies, in terms of abundance, in crops and pastures in Argentina. In order to increase the database on this parasitoid, its prey selection behaviour was studied. Laboratory experiments were made to investigate its preference of host species and instars within species. This parasitoid showed a fastidious behaviour, choosing more often than predicted by chance, first instars ofAllograpta exotica (Wied.).     

The elimination of supernumerary larvae of the gregarious egg-parasitoidTrichogramma embryophagum [Hym.: Trichogrammatidae] in eggs of the hostEphestia kuehniella [Lep.: Pyralidae]

Larvae ofTrichogramma embryophagum Htg., the gregarious parasitoid of eggs of Lepidoptera, ingest the ooplasm of the host by pharyngeal sucking. In the case of a supernumerary number of larvae, some die shortly after all the food has been ingested, although all larvae are still at an early stage of development. The food previously swallowed by the dead animals flows back into the host chorion, and this is ingested by the surviving larvae. As a result of this, there is no wastage of food, and in eggs ofEphestia kuehniella Z. up to 3 larvae always survive to the adult stage.     

Biological and ecological studies of the parasitoidChelonus inanitus [Hym.: Braconidae] in Israel

Only one species ofChelonus Panzer,Chelonus inanitus (L.), was found to be widespread in all areas of Israel. The parasitoid was particularly widespread in alfalfa fields but also was present in cotton, sugar beet, artichoke and corn. Spodoptera littoralis (Boisd) andS. exigua (Hbn.) were the main hosts ofC. inanitus although it might develop in other Lepidoptera species. A study of its population showed that adults were present in the spring, summer and autumn but not during the winter. In most cases the population density of the parasitoid appeared to be related to that of the hosts. Parasitism and sex ratio ofC. inanitus in alfalfa fields were studied. The number of males (average of 75%) was higher than that of the females. Percentage of parasitism in larvae ofS. littoralis andS. exigua reached up to 39.8% and 13.5% respectively. The parasitism values in eggs ofS. littoralis were up to 71%.     

ITS2 sequence variations among members of Diachasmimorpha longicaudata complex (Hymenoptera: Braconidae) in Thailand

The parasitoid Diachasmimorpha longicaudata complex in Thailand contains at least 3 cryptic species informally designated as species D. longicaudata A, B and BB. DNA sequence data of nuclear ITS2 (second internal transcribed spacer) were used to characterize members of this D. longicaudata complex. The polymerase chain reaction (PCR) amplicon of ITS2 region of D. longicaudata B (≈ 650 bp) clearly differentiated this species from A and BB (amplicon of ≈ 590 bp). Sequence alignment of individual parasitoids revealed that low intraspecies differences ranged from 0.457 to 3.991%, but interspecies differences ranged from 7.566 to 12.989%. Phylogenetic trees constructed using Neighbor-Joining (NJ) and Maximum Parsimony (MP) methods, taking the parasitoid Psyttalia concolor complex as an outgroup, revealed that D. longicaudata A, B and BB formed a monophyletic group, with species A and BB being more closely related than species B. ITS2 characterization of D. longicaudata complex has revealed an interesting divergence of the three cryptic sibling species in Thailand.     

Biology ofTrichogramma ostriniae (Hym.: trichogrammatidae) reared onOstrinia nubilalis (Lep.: pyralidae) and survey for additional hosts

Trichogramma ostriniae has been identified as a candidate for biological control ofOstrinia nubilalis. As little was known about the biology of this parasitoid when reared onO. nubilalis, we undertook experiments to quantify biological parameters important to mass-rearing and ase ofT. ostriniae. When reared continuously onO. nubilalis, femaleT. ostriniae on average lived 2.7 days and produced 24 progeny. Continuous access to honey resulted in a four-fold increase in longevity and fecundity and a significant increase in the percentage of females parasitizing eggs. Rates of fecundity and parasitism decreased with age of female. Likewise, emergence rates and percentage of female progeny decreased with age of parental female.T. ostriniae successfully parasitizedO. nubilalis eggs until the blackhead stage. Most parasitism of eggs and eclosion of adults occurred during the first half of photophase. Eggs of 13 Lepidopterans were parasitized byT. ostriniae. Eggs of the Noctuidae, Pyralidae, and Plutellidae experienced higher levels of parasitism than others tested.T. ostriniae appears to be similar to other species ofTrichogramma in several respects and does not possess any characteristics that limit its potential for mass rearing and use for augmentative biological control ofO. nubilalis.