Biological studies ofBrachyserphus abruptus [Hym.: Proctotrupidae], a nitidulid parasite

Data are presented on survival, fecundity, and hosts ofBrachyserphus abruptus (Say), a solitary internal parasite of nitidulid (sap beetle) larvae. In the laboratory these wasps have been successfully reared fromCarpophilus hemipterus (L.),C. freemani Dobson,C. lugubris Murray,Stelidota geminata (Say),S. octomaculata (Say),S. ferruginea Reitter,Glischrochilus quadrisignatus (Say),Lobiopa insularis (Castelnau), andHaptoncus luteolus (Erichson). Field collections ofB. abruptus have been made fromS. geminata, S. octomaculata, C. hemipterus, C. lugubris, L. insularis andH. luteolus. Oviposition continues throughout most of the adult female's lifetime. Under laboratory conditions life expectancy of females wasca. 6 days. Mean number of progeny reaching adulthood per female was 57, with a 1∶1 sex ratio. First and 2^nd instar nitidulids were suitable for successful development ofB. abruptus. Third instars were attacked byB. abruptus but were not successfully parasitized. Parasite development required 29 days in 1^st instar hosts and 27 d. in 2^nd instars. Percent parasitism in 1^st instarC. hemipterus averaged 65% and for 2^nd instar 45%. After parasitism, larvae ofC. hemipterus surviving to become adults averaged 0.6% for 1^st instar, 9.3% for 2^nd instar, and 90% for 3^rd instar. This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or a recommendation for its use by The Ohio State University.     

Literature review ofOoencyrtus kuvanae [Hym.: Encyrtidae], an egg parasite ofLymantria dispar [Lep: Lymantriidae]

Literature onOoencyrtus kuvanae (Howard) from throughout the world is reviewed. References from Asia, Japan, Europe, Africa, and North America, covering the years 1900–1983, are included. The information is divided into the following subject areas: taxonomy, host range, distribution and introductions, biology and life history, host suitability, behavior and spatial distribution, effectiveness, and population dynamics. Suggestions for future research are presented.     

A new species ofPseudaphycus [Hym.: Encyrtidae], with notes on theAngelicus group

The genusPseudaphycus Clausen and related genera are considered to belong in the subfamilyTetracneminae. P. debachi, n. sp., a parasite of the striped mealybugFerrisia virgata (Cockerell) from Mexico, is described and compared morphologically to several closely-related members of theangelicus group of species.

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Résumé Le genrePseudaphycus Clausen et les genres voisins sont considérés appartenir à la sous-famille desTetracneminae. L'espèceP. debachi, n. sp., parasite de la cochenilleFerrisia virgata (Cockerell) du Mexique, est décrite et comparée morphologiquement à plusieurs membres très voisins du groupe d'espècesangelicus.

     

Biological studies withChrysocharis parksi [Hym.: Eulophidae] a parasite ofLiriomyza spp. [Dipt.: Agromyzidae]

Biological studies withChrysocharis parksi Crawford, a parasite of agromyzid leafminers, were conducted.C. parksi successfully parasitized the following species in the genusLiriomyza Mik.,L. huidobrensis (Blanchard),L. sativae Blanchard,L. trifolii (Burgess), andL. trifoliearum Spencer. Successful parasite development was recorded from 8 plant families and 16 genera. Host plants which were suitable for leafminer development to the adult stage were also suitable for parasite development. Mean immature developmental period (egg to adult, usingL. trifolii as the host) at 21.1°, 26.7°, and 32.2° C was (for both sexes) 23, 14, and 14 days, respectively. Longevity of females provided only water was inversely related to temperature; significantly longer survival occurred at 21.1° C (5.0 days) compared to 26.7° C and 32.2° C (3.2 and 2.1 days, respectively). The addition of honey to the diet significantly improved longevity of both sexes at all temperatures. Adult female parasites which were provided an average of 33.0L. trifolii larvae per day produced an average of 135 offspring at a constant 26.7° C.C. parksi host-fed on ca. 3.7 leafminer larvae per day over an 11-day adult lifespan.      

Laboratory studies ofDiadegma cerophagus [Hym.: Ichneumonidae], a parasite introduced to controlPlutella xylostella [Lep.: Hyponomeutidae] in Malaysia

Laboratory studies were conducted to determine some of the attributes ofDiadegma cerophagus Gravenhorst, a parasite introduced to controlPlutella xylostella (L.). Longevity studies have shown that ♂ and ♀ could live for 40 and 73 days respectively when fed on diluted honey. The parasite is capable of attacking an average of 117±10 caterpillars per ♀. The number of caterpillars attacked per ♀ is dependent on the life span of the ♀. The average area of discovery ofD. cerophagus, based on studies of single searching parasites, was found to be 1.20±0.21. The area of discovery was found to decrease with increase in parasite or host density. However, the k-value would increase with increasing parasite density and decrease with increasing host density. The life-cycle ofD. cerophagus is as follows: egg stage, 1.5 to 2 days; larval stage, 5 to 8 days and pupal stage, 6 to 9 days. There are 4 larval instars and the duration of each instar is dependent on the age of the host attacked. The duration of the larval stage averaged 6.5 days when 1- and 2-day old caterpillars were exposed toD. cerophagus and took 5 days when 3- and 4-day old caterpillars were exposed.     

Biology ofIphiaulax kimballi [Hym.: Braconidae], a parasite ofDiatraea grandiosella [Lep.: Pyralidae]

Iphiaulax kimballi Kirkland is a gregarious ectoparasite of the mature larval stage ofDiatraea grandiosella Dyar in Mexico. The developmental rate from egg to adult is 16.3±1.0 (x±S.D.) at 29°C. The sex ratio is 1.7∶1 (♀∶♂) in the field. Following host paralysis the female deposits 63.5±2.1 eggs during der 28.6±6.4 day adult-life span; laying 4.6±3.1 eggs on each host. Females held at 10°C lived a maximum of 3 months.     

Predators ofBathyplectes curculionis [Hym.: Ichneumonidae], a parasite ofHypera postica [Col.: Curculionidae]

Invertebrate predation was shown to be the greatest mortality factor on diapausing larvae ofBathyplectes curculionis (Thomson) in Illinois. Feeding tests were conducted in which specific predators were determined by exposingB. curculionis larvae to various surface dwelling invertebrates found in alfalfa fields. In addition, field plantings of parasite larvae in modified cages were used to determine the size of predators, and also, if litter density affected predation. Seasonal activity ofB. curculionis predators was also measured from 4 April 1975 to 18 November 1975 via 15 pitfall traps located in 3 alfalfa fields. Results from feeding studies showed that spiders,Cicindelidae, Formicidae and smallStaphylinidae never preyed uponB. curculionis larvae in cocoons. The 2 groups of predators which consumed the larvae were field crickets,Gryllus pennsylvanicus Burm., and various species ofCarabidae. Predation on the parasite larvae planted in the field was mainly caused by moderately sized invertebrates, and was not significantly affected by litter density. The greatest number of total predators (G. pennsylvanicus plus Carabids) caught/day/pitfall trap, and the greatest predation on field-plantedB. curculionis larvae, occurred concurrently during September and October. These data suggest that predation during September and October may be significant in reducing field populations of diapausing parasite larvae. Based on feeding studies and pitfall trap catches,Gryllus pennsylvanicus and the carabids,Abacidus permundus (Say),Evarthrus sodalis LeConte,Harpalus pennsylvanicus DeGeer andScarites subterraneus Fab., were the most important predators onB. curculionis larvae.

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Résumé Il a été montré que les prédateurs invertébrés sont le plus grand facteur de mortalité des larves en diapause deBathyplectes curculionis (Thomson) en Illinois. On a fait des essais alimentaires dans lesquels on a déterminé des prédateurs spécifiques en exposant les larves deB. curculionis à divers invertébrés trouvés dans les champs de luzerne. De plus, des larves du parasite, dans des cages modifiées implantées dans les champs, ont été employées pour vérifier la taille des prédateurs et aussi pour savoir si la densité de la litière a influencé les prédateurs. L'activité saisonnière des prédateurs deB. curculionis a été mesurée du 4 avril 1975 au 18 novembre 1975 au moyen de 15 pièges placés dans 3 champs de luzerne. Les résultats des essais alimentaires montrent que les araignées,Cicindelidae, Formicidae et de petitsStaphylinidae n'ont jamais utilisé comme proie les larves en cocon deB. curculionis. Deux groupes de prédateurs ont consommé les larves: les grillons,Gryllus pennsylvanicus Burm., et des espèces variées deCarabidae. Pour la plupart ce sont des invertébrés de taille modérée qui ont utilisé comme proie les larves implantées dans les champs, la densité de litière n'étant pas significative. Le plus grand nombre de prédateurs au total (G. pennsylvanicus plusCarabidae) attrapés par jour et par piège et la plus grande consommation de larves deB. curculionis se sont produits concurremment en septembre et en octobre. Ces données indiquent que les prédateurs en septembre et octobre peuvent être très importants pour réduire le nombre de larves parasites en diapause. Si l'on juge selon les essais alimentaires et selon ce qu'on a attrapé dans les pièges,Gryllus pennsylvanicus et lesCarabidae, Abacidus permundus (Say)tEvarthrus sodalis LeConte,Harpalus pennsylvanicus DeGeer,et Scarites subterraneus Fab., on, constitué les prédateurs spécifiques les plus importants des larves deB. curculionis.

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This publication was supported by the Illinois Natural History Survey, The Illinois Agricultural Experiment Station, National Science Foundation, and the U.S. Environmental Protection Agency, through a grant (NSF GB-34718) to the University of California. The findings, opinions and recommentations expressed herein are those of the author(s) and not necessarily those of the University of California, the National Science Foundation and the Environmental Protection Agency.     

Competitive displacement ofAnagyrus antoninae [Hym.: Encyrtidae]. by its ecological homologueNeodusmetia sangwani [Hym.: Encyrtidae]

The displacement ofAnagyrus antoniaae Timberlake byNeodusmetia sangwani (Rao) was demonstrated by reduced parasitism by the former in two localities after the latter was introduced into these sites. The competitive factors were: (1) the host-regulative action ofN. sangwani maintained a low host reciprocal balance, and (2) the inability of the female ofA. antoninae at the prevailing host density to find hosts sufficient for reproduction. The lack of competitiveness ofA. antoninae was a result of its inability to develop at high vapor deficits.     

Host discrimination byChelonus insularis [Hym.: Braconidae], telenomus heliothidis [Hym.: Scelionidae], andTrichogramma pretiosum [Hym.: Trichogrammatidae]

The ability of female parasitoids (Chelonus insularis Cresson,Telenomus heliothidis Ashmead, andTrichogramma pretiosum Riley) to distinguish between parasitized and unparasitized tobacco budworm,Heliothis virescens (F.), eggs was determined in laboratory studies. All 3 species were relatively efficient at detecting eggs that were previously parasitized by conspecific females.T. heliothidis andT. pretiosum were able to discriminate on the basis of external examination of host eggs, whereasC. insularis appeared to examine hosts internally as well as externally. In interspecific tests, no species readily rejected eggs parasitized by the other 2 species.     

Establishment of the imported parasitePentalitomastix plethoricus [Hym.: Encyrtidae], onEctomyelois ceratoniae [Lep.: Phycitidae] in Israel

Pentalitomastix plethoricus Calt. was imported to Israel to aid in the biological control ofEctomyelois ceratoniae (Zell.). Two to 3 years following release in almonds the parasite was found established onE. ceratoniae with 12–15% parasitism. In carob plantations, on the other hand, 3 to 5 years after release the parasite was not recovered fromE. ceratoniae. We suggest that the type of host plant — almond in this case — is a determining factor for establishment of the parasiteP. plethoricus.     

The biology ofAphelinus flavus [Hym. Aphelinidae], a parasite of the Sycamore aphidDrepanosiphum platanoides [Hemipt. Aphididae]

Aphelinus flavus Thompson is a solitary internal parasite. Males and females overwinter as free living adults and appear on sycamore in mid, May. The female consumes aphid body fluids and kills 1 aphid for food for every 1.7 eggs deposited, and parasitises 48 aphids over 27 days. Development from egg to adult requires and parasitises 48 aphids over 27 days. Development from egg to adult requires 57 days. The mortality of parasites while within the nummified host was determined: it was related to hyperparasitism and predation. Mortality due to mummies being brushed off the leaves was also determined.     

Aphytis riyadhi n. sp. [Hym.: Aphelinidae], a parasite ofAonidiella spp. [Hom.: Diaspididae]

A new species ofAphytis reared fromAonidiella orientalis collected from citrus in Saudi Arabia is described and compared morphologically with four other closely relatedAphytis species.

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Résumé Aphytis riyahdi n. sp., parasite deAonidiella orientalis (Newst.) en Arabie Saoudite a été importé en Californie pour procéder à des lachers contreAonidiella aurantii (Maskell) afin d'améliorer la lutte biologique contre cette cochenille dans une zone de vaste superficie et de climats variés.

     

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.     

Variation du comportement chezMetaphycus lounsburyi [Hym.: Encyrtidae]

Résumé L'étude du comportement de trois populations naturelles deMetaphycus lounsburyi Howard de Californie, Espagne, Italie, montre d'importantes (comportement de ponte, accouplements hétérogamiques) ou de faibles différences (réceptivité de l'h?te, décalage des niches écologiques), sans différences morphogiques.M. lounsburyi est considéré comme une super-espèce. Deux semi-espèces sont reconnues (méditerranéenne, californienne importée d'Australie) qui sont jugées comme suffisamment isolées génétiquement, pour être utilisées dans les mêmes vergers en vue de la lutte biologique contre la cochenille noire de l'olivier et des agrumes,Saissetia oleae (Olivier).

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Summary Behavioural study of 3 natural populations ofM. lounsburyi Howard from California, Spain, Italy, shows large (egg-laying behaviour, heterogamic matings) or little differences (host acceptance, shifting of ecological niches), without morphological differences.M. lounsburyi is considered as a super-species. Two semi-species are recognized (Mediterranean, Californian imported from Australia) which are sufficiently isolated genetically, to be used in the same orchards for biological control against the Olive and Citrus Black Scale,Saissetia oleae (Olivier).

     

Bionomies comparées de deux souches (Marocaine et Américaine) d’Ooencyrtus kuvanae [Hym.: Encyrtidae], parasite oophage deLymantria dispar [Lep.: Lymantriidae]

Résumé Des adultes d’Ooencyrtus kuvanae (Howard) sortis d’œufs deLymantria dispar (L.) récoltés au Maroc et aux états-Unis ont été élevés séparément mais simultanément dans les mêmes conditions abiotiques. On a évalué chez ces adultes des caractéristiques bionomiques telles que la longévité, la proportion de ♀ fécondes, la fécondité réelle moyenne, la durée de la période de ponte et le pourcentage d’œufs viables développés par parthénogenèse. Chez la progéniture, on a évalué la survie des larves et la proportion de ♀. Aucune différence significative entre les 2 souches n’est apparue. Des croisements entre les 2 souches ont donné une descendance comportant des proportions équivalentes de ♀.O. kuvanae avait été introduit au Maroc en 1926 depuis les états-Unis. Ainsi, 50 années d’acclimatation de ce parasite au Maroc (soit près de 500 générations) n’ont pas modifié ses potentialités et n’ont pas suffi à induire chez lui une nouvelle race géographique.

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Summary Adults ofOoencyrtus kuvanae (Howard) were recovered from eggs ofLymantria dispar (L.) collected in Morocco and in the U.S.A. They were reared separately and simultaneously under identical laboratory conditions. Various biological characteristics of adults from both sources were compared including longevity, proportion of fertilized versus unfertilized females, fecundity, duration of the oviposition period, and the percentage of viable eggs produced by virgin females. Also the survival of the larvae and the sex ratio of the 2 cultures were evaluated. Crossbreeding individuals of the 2 cultures resulted in a similar proportion of females in the progeny. In general there were no significan differences found between the 2 cultures.O. kuvanae had been introduced in Morocco in 1926 from the U.S.A. The adaptation of this parasite to conditions in Morocco during the ensuring 50 years since its establishment (about 500 generations) did not appear to modify the biotic potential of this species nor was it sufficient to induce the development of a new geographic race.

     

Biological studies ofDiadegma semiclausum (Hym., Ichneumonidae), a parasite of diamondback moth

Laboratory studies were conducted on certain aspects of biology ofDiadegma semiclausum Hellén, a larval parasite of a crucifer pest,Plutella xylostella (L.). Within the range of 15°C to 35°C, the higher temperature, the shorter was the duration of larval and adult stages. Egg hatching and adult emergence were high at 15°C to 30°C but were significantly reduced at 35°C. The higher the temperature, the higher was the proportion of males produced. Temperature threshold was 5.74°C for eggs, 3.80°C for larvae, 5.91°C for pupae and 6.60°C for adults.D. semiclausum oviposition in the first threeP. xylostella larval instars produced more parasite males than females but oviposition in the fourth instar produced significantly more females than males. Parasite adults tended to emerge from their pupae from 06∶00 to 09∶00 hours although some emerged at other hours during the photophase. Adult longevity and production of eggs increased when adults were provided with a food source (honey) compared with no food or provision of water alone. Parasite adults survived and laid eggs for 28 days when provided with food but for only three days when deprived of food.     

Preliminary studies on the efficacy and establishment ofRoptrocerus xylophagorum [Hym.: Torymidae], a parasitoid ofIps grandicollis [Col.: Scolytidae], in Australia

Parasitization ofIps grandicollis Eichhoff byRoptrocerus xylophagorum (Ratzeburg), and intra-specific competition withinIps broods, were studied under laboratory conditions. Largest numbers of immatureR. xylophagorum were found in logs sampled when about half theIps brood were callow adults. Rates of parasitization rarely exceeded 20 %, and were usually much lower. Numbers of parasitoids were not affected by bark thickness. In the absence of parasitism,Ips broods suffered a density-dependent mortality which increased greatly in intensity and continued to act later in development of the broods when initial densities of larvae exceeded a threshold of about 400 per 1 000 cm² of bark. The possible significance of this mortality is discussed in relation to the ability of parasitoids to reduceIps numbers. A field experiment was done to investigate the ability ofR. xylophagorum to establish in a new habitat. Populations were established for 1 or more generations by releasing 50 females at sites prepared by supplying small numbers of logs containing immatureIps.     

A new host record forTachinaephagus zealandicus [Hym.: Encyrtidae]

Tachinaephagus zealandicus Ashmead was reared from puparia ofProtocalliphora n. sp. [Dip.], representing a new host record for this parasitoid. The habitat ofProtocalliphora is qualitatively different than those of all previously recorded hosts for this parasitoid.T. zealandicus has been imported from Australia and New Zealand and this record strengthens the belief that it has become established in California.     

Aerial dispersal ofScelio fulgidus [Hym.: Scelionidae], parasite of eggs of locusts and grasshoppers [Ort.: Acrididae]

Scelio fulgidus Crawford, a hymenopterous parasite of eggs ofAcrididae, was discovered in samples of the aerial fauna, collected at 100–300 m altitude over grassland at a site in central western New South Wales at 2 sampling periods in October/November 1979. The parasite was recorded throughout the day in conditions of convective uplift suggesting that extensive diurnal dispersal occurred on the prevailing wind at distances varying from 100 to 300 km per day. Take-off at dusk of its major host, the Australian plague locust (Chortoicetes terminifera Walker), was observed in one period and direct aerial sampling at 100–300 m altitude subsequently confirmed the presence of this locust in the upper airflow at night. The mean wind vector did not differ greatly between day or night during this sampling period, suggesting that parasite and host were dispersed independently over the same general area by prevailing winds. Aerial dispersal provides a new explanation of the parasitism byScelio of egg beds of immigrant swarms of the plague locust in areas where hosts were previously absent.     

Key to palaearctic species of the genusPsyllaephagus [Hym.:Encyrtidae]

The article contains a key to 42 species of the genusPsyllaephagus Ashmead, 1900—parasites ofPsylloidea, mainly from southern regions of Palaearctics.Psyllaephagus tobiasi Trjapitzin, 1967 is synonymized withP. belanensis (Hoffer, 1963).

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Résumé Il est fourni la clé de 42 espèces du genrePsyllaephagus Ashmead, 1990, parasites de psylles, principalement des régions méridionales de la zone paléarctique.Psyllaephagus tobiasi Trjapitzin, 1967 est mis en synonymie avecP. belanensis (Hoffer, 1963).