Rearing and life history studies onBiosteres (Opius) longicaudatus [Hym.: Braconidae]

Efficient methods were developed for rearingBiosteres (Opius) longicaudatus Ashmead, using the Caribbean fruit fly,Anastrepha suspensa (Loew), as the host. Evaluations were made of the influence upon parasite survival and reproduction of the host's diet and of CO₂ and N₂ anaesthesia, chilling, and aspiration as adult collection methods. Data were obtained on aspects of the life history ofB. longicaudatus.     

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.     

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.     

Influence of parasitoid-host density and host availability on the laboratory propagation ofMicroctonus aethiops [Hym.: Braconidae] parasitoid ofHypera postica [Coleop.: Curculionidae]

Laboratory studies of the arrhenotokous braconid wasp,Microctonus aethiops (Nees) were conducted relative to maximizing parasitoid production without adversely affecting sex ratios of the progeny. The influence of hostHypera postica (Gyllenhal) and parasitoid densities on parasitoid productivity was evaluated. Maximum production or a mean 25.8M. aethiops progeny were obtained per female when the host parasitoid ratio was 50∶1. More than one parasitoid per rearing cage resulted in fewer parasitoid progeny per female and increased host mortality. Oviposition significantly increased when female parasitoids were exposed to 25 different weevils every 24 hours. The most intense ovipositional activity usually occurred during the first 48 hours of exposure. However, superparasitism occurred if exposure to 25 hosts continued for more than 24 hours. Continuous and discontinuous oviposition patterns did not affect the numbers of parasitoid progeny produced. However, fewer females were produced when new weevils were provided every 24 hours as in the continuous oviposition group.     

Effects of host age and cocoon position on attack rate by the hyperparasitoid,Eurytoma sp. [Hym.: Eurytomidae], on cocoons of the parasitoid,Cotesia (=Apanteles) glomerata [Hym.: Braconidae]

Host age preference of the hyperparasitoid,Eurytoma sp., attacking the cocoons of the gregarious parasitoid wasp,Cotesia (=Apanteles) glomerata L., was investigated in the field and laboratory. Under laboratory conditions of 20°C and L16D8 photoperiod.Eurytoma sp. parasitized cocoons of all ages, laying 7 to 10 eggs per cluster during a 24 h period. Field-collected cocoons also indicated that the host was parasitized regardless of its developmental stage. However, the mortality ofEurytoma sp. laid in cocoons on the day before host emergence was as high as 60%. Furthermore, progeny sex ratio (proportion males) reached 0.708 in eggs laid in the oldest cocoon clusters, whereas that for younger cocoons was strongly female-biased. Together, these facts suggest that older hosts are less suitable forEurytoma sp. than are younger ones, even though there was no significant decreasing tendency in the number of parasitized cocoons per cluster. In addition, the effect of cocoon position within a cluster was apparent, outer cocoons being more easily parasitized than inner ones. TheEurytoma sp. female oviposited at random on the free surface ofC. glomerata cocoons.     

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.     

Influence of maternal age and host deprivation on egg production and parasitization byMicroplitis croceipes [Hym.: Braconidae]

The effect of maternal age and hostHeliothis virescens (F.) deprivation on egg production and allocation byMicroplitis croceipes (Cresson) was determined in the laboratory on 0.5, 1.0, 3.0, 6.0, 9.0, and 12.0 days old parasitoids. In host-deprived parasitoids, newly-emerged (0.5-day old) females produced significantly fewer eggs than older ones; egg production peaked 3 to 6 days after emergence and declined thereafter. However, the number of eggs found in undeprived parasitoids at various ages suggested a cyclical pattern of egg production. The rate of parasitization by host-deprivedM. croceipes was higher in 1.0 to 6.0 days old than in newly-emerged or older females and was correlated strongly with egg production (r=0.93). The first observation on premature larval hatching inM. croceipes was documented.      

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.     

Effects of temperature and photoperiod on the development and oviposition ofApanteles sp. groupUltor [Hym.: Braconidae], a larval parasite of the carob mothEctomyelois ceratoniae [Lep.: Pyralidae]

Development of the solitary parasitoidApanteles sp. groupultor in larvae ofEctomyelois ceratoniae was investigated at different constant temperatures. Temperature had a significant effect upon parasitoid development during both host-internal and host-external phases. The duration of the host-internal phase varied from 41 days at 15–17°C to 8.6 days at 29°C, the duration of the host-external phase varied from 16.5 days at 16–17°C to 5.4 days at 29°C. Effect of photoperiod upon parasite development and parasitization of hosts were determined under daily photophases, of 24, 16, 12, 8 and 0 hours. No significant differences in oviposition rate were found among the 5 treatments. In any photoperiod studied, the parasite progeny developed normally without entering diapause.      

Greenbugs [Hom.: Aphididae] forced from host plants byLysiphlebus Testaceipes [Hym.; Braconidae]

In a laboratory study 150 sorghum plants were infested with greenbugs,Schizaphis graminum (Rondani), of ages 1, 3, and 5 days in densities of 5, 10, and 20 aphids per plant. Seventy-five of these infested plants were exposed to mated femaleLysiphlebus testaceipes (Cresson), and the number of aphids leaving each plant in a 4-hr period was recorded. Of the 75 plants exposed to parasitoids, an average of 41.0% of the aphids left the plants, compared to 0.9% from the 75 control plants. Twenty-six of the 75 parasitoids used in the experiment were inactive in the presence of aphids, showing no interest in searching for hosts. The number of inactive parasitoids was inversely related to the number of aphids per plant. When only those plants exposed to active parasitoids were considered, an average of 62.8% of the aphids left. To determine the fate of greenbugs leaving plants on hot, sunny, summer days, a small field test was performed in which greenbugs were knocked from plants onto soil exposed to direct sunlight. Air temperature was ca. 29°C and soil temperatures ranged from 45°C to 54°C. Twenty-four greenbugs were knocked to the soil, and all of them ceased activity within 10 seconds and were apparently dead.     

Forest and laboratory evaluations of hybridizedApanteles melanoscelus [Hym.: Braconidae], a parasitoid ofPorthetria dispar [Lep.: Lymantriidae]

Hybrids ofApanteles melanoscelus (Ratzeburg) were produced from colonies originating from France, Yugoslavia, and Connecticut. All strains, as well as freshly collected “wild” Connecticut parasitoids of the same species were evaluated in the laboratory for developmental rate, host attack rate, and sex ratios. Development was significantly slower in all the laboratory strains compared to the progeny of forest collected Connecticut females. Progeny production was greater (almost 2X) for the “wild” females and the French-Yugoslavian-Connecticut hybrid than for the laboratory Connecticut strain. The proportion of females collected from the “wild” (Connecticut) strain was higher than that observed in any laboratory strain. A field test was conducted using the triple hybrid in 3 release plots with ca. 6000A. melanoscelus cocoons released per plot in central Connecticut, U.S.A. Weekly collections of gypsy moth larvae showed that the % parasitism was significantly higher in release plots than in the 3 check plots. These results suggest the value of inundative releases ofA. melanoscelus for reduction of sparse gypsy moth populations, but they did not show that hybridization of these strains produced a more effective parasitoid under forest conditions.     

Allorhogas pyralophagus [Hym.: Braconidae], a gregarious external parasite imported into texas,USA, for biological control of the stalkborerEoreuma loftini [Lep.: Pyralidae] on sugar cane

Allorhogas pyralophagus Marsh is a recently discovered doryctine braconid with potential for field trials against stalk borers infesting both large- and small- stemmed Graminacea. This external gregarious parasite was originally reared fromEoreuma loftini (Dyar) larvae infesting Johnson grass [Sorghum halepense (L.) Pers.] and sugar cane (Saccharum officinarum L.) from the states of Sinaloa and Nuevo Leon, Mexico. The parasite is easily reared in the laboratory using a wide range of host larvae [Diatraea spp.,E. loftini, Chilo sp. andTryporyza nivelli (F)]. Hosts are placed in grass stems or paper straws for exposure to ovipositing females.A. pyralophagus has been field released and recovered from the following hosts infesting sugar cane:E. loftini andD. saccharalis (F.) in Texas.Diatraea spp. in Trinidad,D. rufescens in Bolivia andT. nivella in Sumatra, Indonesia. Approved as Contribution No. TA-20743 of the Texas Agricultural Experiment Station.     

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.

     

Seasonal history ofMacrocentrus grandii [Hym.: Braconidae] andEriborus terebrans [Hym.: Ichneumonidae], two parasitoids of the European corn borer,Ostrinia nubilalis [Lep.: Pyralidae]

The seasonal histories and phenological relationships of European corn borer,Ostrinia nubilalis (Hübner), and its 2 parasitoids,Macrocentrus grandii (Goidanich) andEriborus terebrans (Gravenhorst) were studied in southcentral Minnesota. Both parasitoids overwintered in mature borer larvae, broke diapause, completed development, and emerged at the same time as did borer adults. Thus the 1st generation parasitoids coincided with the peak abundance of their preferred larval instars of the 1st host generation. Both parasitoids had a 2nd generation, matching the bivoltinism ofO. nubilatis in Minnesota. The activity of 2nd generationE. terebrans was before the peak 2nd generation borer moth flight and was not synchronized with the peak abundance of 2nd generation borer larvae. The peak activity of 2nd generationM. grandii occurred after the peak 2nd generation borer moth flight and was fully synchronized with the peak abundance of 2nd generation borer larvae. Thus,M. grandii has both generations synchronized with the host seasonal history, and was the more effective of the 2 parasitoids.     

Determination of host range in relation to systematics forPeristenus stygicus [Hym.: Braconidae], A parasitoid ofMiridae

Peristenus stygicus Loan develops inMirinae speciesLygus hesperus,Knight,L. lineolaris, (Palisot de Beauvois) andPolymerus basalis (Reuter),Orthotylinae speciesLabopidicola geminata (Johnston),Phylinae speciesPseudatomoscelis seriatus (Reuter) and partially develops in the mirineDichrooscytus sp. The parasitoids attackMicrophylellus maculipennis (Knight) (Phylinae) and another orthotyline species, but do not develop in these.Taedia johnstoni (Knight) (Mirinae), 2 species ofBrycorinae and 3 species ofLygaeidae are not acceptable as hosts. Olfactometer studies show the parasites are significantly more attracted to lygus nymphs whenPhaseolus vulgaris L. is present than either the nymphs or bean alone. Host color, mobility, size, previously infested plant material, and host plant species are rejected as host selection criteria.     

Effect of parasitism byAscogaster reticulatus [Hym.: Braconidae] on growth of the host,Adoxophyes sp. [Lep.: Tortricidae]

The developmental interaction between the egg/larval parasitoid,Ascogaster reticulatus Watanabe (Hymenoptera: Braconidae) and its host,Adoxophyes sp. (Lepidoptera: Tortricidae) was examined. Prior to the egress of a final-instar parasitoid larva from the 4^th-instar host larva, host weight decreased by 22% from the maximum weight. The final body weight of a host larva was 27% of the maximum weight of a healthy 5^th-instar host. Food consumption was significantly reduced in both 3^rd-and 4^th-instar parasitized larvae compared with healthy ones. In the 4^th instar, a parasitized larva consumed 28% less artificial diet and produced less frass than a healthy larva. The growth rate of the endoparasitoid larvae greatly increased after their host's molt to the 4^th instar. Parasitoid larval volume increased 40 fold in the 4^th-instar host.      

Regulation of host larval development by the egg-larval endoparasitoidChelonus insularis [Hym.: Braconidae]

In laboratory studies the effect of parasitism by the egg-larval endoparasitoidChelonus insularis Cresson on the resulting larvae of 2 host species,Heliothis virescens (F.) andSpodoptera ornithogalli Guénée) were determined by comparing daily measurements of larval weights. Growth of parasitized larvae of both host species was slower than growth of unparasitized larvae. Injections of fluids from the female parasitoid's calyx or poison gland intoH. virescens eggs retarded subsequent larval growth. However, a combination of fluids from these 2 organs produced the most significant reduction in the host larval growth rate. The growth reducing factor(s) was also effective when injected into 5-day-old host larvae.     

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.     

Effects of bacterial contamination on development ofMicroplitis croceipes [Hym.: Braconidae]

Bacterial contaminants ofHeliothis virescens (F.) influenced the development ofMicroplitis croceipes (Cresson). Among the four bacterial species studied, the most virulent wasPseudomonas maltophilia Hugh and Ryschenkow followed byBacillus subtilis (Ehrenberg) Cohn. Both bacteria caused severe mortality in all stages ofMicroplitis tested.Microplitis larvae were less susceptible toEscherichia coli (Migula) Castellani and Chalmers andLeuconostoc mesenteroides (Tsenkovskii) van Thieghem than toB. subtilis andP. maltophilia. AlthoughE. coli did not affect the number of cocoons produced, adult emergence was lower than in controls. Longevity of adultMicroplitis exposed to bacterially contaminated honey-water was greatly reduced in all bacterial treatments.