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Cotesia chilonis (Munakata) is an endoparasitoid wasp of Chilo suppressalis Walker (Lepidoptera: Pyralidea) larvae. Little is known regarding the tolerance of C. chilonis after cold acclimation at different temperatures. In this study, we investigated mortality and the molecular basis of temperature tolerance in C. chilonis reared under normal conditions (27°C) and after cold acclimation at 4°C for 5 d. We evaluated the relative expression of five genes encoding heat shock proteins (HSPs) in C. chilonis by RT-qPCR after cold acclimation and exposure to temperature stress. The results demonstrated that cold acclimation could significantly enhance the survival of C. chilonis adults under high temperatures, and expression of the five C. chilonis HSP genes had distinctly different expression patterns in response to temperatures. Cchsp40 and Cchsp90 had similar expression pattern that upregulated significantly at −12 and 39°C. Cchsp70 could be induced by high and low temperatures, whereas Cchsp60 and Cchsc70 showed no significant difference in expression when exposed to thermal stress. This study provides important biological information that may help extend the shelf life of C. chilonis, which is an important consideration in the use of this wasp as a biological control agent.

Koinobionts are parasitoids that allow their hosts to grow after infection, and they finally kill their host individuals at parasitoid-specific host stages. Since fatal accidents of host organisms directly result in the deaths of parasitizing koinobionts, a longer parasitization period in vulnerable hosts is likely to increase the mortality of the koinobionts. However, for hosts inhabiting concealed environments in their later developmental stages, koinobionts should begin parasitization in early-stage hosts to make use of the grown hosts. A koinobiont parasitoid, Aneurobracon philippinensis (Muesebeck), mainly uses a leaf-mining moth, Acrocercops transecta Meyrick (Lepidoptera: Gracillariidae) as a host. Due to the three-dimensional structure of the mines constructed by later instars of A. transecta, females of A. philippinensis seldomly oviposit into later instar hosts, whereas feeding on final instar hosts is essential for A. philippinensis larvae. This implies that oviposition targets in the wild are shifted to early instars, though the final instar is the ideal target to shorten the parasitization period. The dissection of wild host larvae demonstrated that no eggs were observed in the final instar, supporting the above expectation. Laboratory parasitization experiments revealed that A. philippinensis eggs hatched approximately 80 h after oviposition, and hatched larvae stayed in the first instar until the host larvae completed making cocoons. These results suggest that the first-instar period of the parasitoid larvae functions as an adjusting period to synchronize the parasitoid and host developmental stages and that koinobiosis plays an important role in utilizing the final instar of A. transecta as a resource.

Tannins are ubiquitous secondary plant compounds that reduce the biological performance of herbivores by impeding protein metabolism. They may also impact the third trophic level when parasitoids or predators ingest herbivore tissues containing tannins. Microplitis mediator (Haliday) (Hymenoptera: Braconidae) is an important parasitoid of polyphagous moth species such as Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae). In this study, we analyzed the direct and indirect effects of tannic acid on M. mediator development and longevity when wasps either fed directly on tannic acid in honey solution, or developed in H. armigera larvae reared on diet containing tannic acid. The longevity of both male and female M. mediator was shortened when they fed on honey solution containing various concentrations of tannic acid. Transgenerational effects were also evident, as fewer F1 offspring cocooned successfully, and those that did so often had extended developmental times and lower mass of cocoon. When parasitoid larvae developed in host larvae fed tannic acid in their diet, the percentage cocooning successfully, mass of cocoon, and cocoon time were all negatively impacted, although developmental times were unaffected. Surprisingly, the longevity of both male and female parasitoids was extended by the highest tannic acid concentration (5 mg/g of host larva). We conclude that both direct and indirect consumption of tannic acid can negatively affect the fitness of M. mediator , and thus breeding for tannin content in cotton to impede herbivore performance may have unintended effects on the third trophic level that may reduce the agronomic benefits.

Although functional response and mutual interference studies may be of great importance to augmentative biological control projects focussed on pests of economic importance, such studies have traditionally been overlooked in mass rearing projects of natural enemies. In this study, we aimed to explore both interactions in Utetes anastrephae (Viereck), a native parasitoid commonly associated with Anastrepha obliqua (Macquart), a major fruit fly pest of Spondias spp. and Mangifera indica L. in the Americas, for mass rearing purposes. The functional response of U. anastrephae on A. obliqua larvae fit a type II model according to Holling’s disc equation, with an instantaneous rate of discovery ( a ') of 0.470 and a handling time ( Th ) of 0.099. The effects of mutual interference were more severe at high parasitoid densities due to the higher frequency of interactions. An increasing number of foraging females resulted in an increasing number of oviposition scars and immature parasitoids per pupa without significant differences in the total number of attacked larvae. Superparasitism at high densities of foraging females had a negative effect on adult emergence, was associated with a female-biased sex ratio, and had no effect on survival or flight ability parameters. Strategies for optimizing the mass rearing of this parasitoid species are outlined.

Ornamental trees are valuable natural elements which provide several economic, aesthetic, and ecological benefits to humans. They are seriously infested by numerous pests and diseases, among which aphids are of high importance. Here we present a comprehensive list of Aphidiinae parasitoid species that attack aphids on ornamental trees in southeastern Europe, some of which are potential biocontrol agents. Thirty-eight species of Aphidiinae are recorded, keyed, and illustrated. Fifty-six out of 120 recorded tritrophic (parasitoid – aphid – plant) associations were previously unknown. The results are discussed in relation to the overall parasitoid – aphid – tree associations in the target region, as well as potential of parasitoid use in biological control programs.

The evolution of tritrophic interactions requires adaptations of natural enemies to both herbivorous hosts and host foodplants that can ultimately lead to the formation of locally adapted populations, host races, or ecological species. To situate our model organism, Cotesia congregata (Say), within this spectrum, we estimated genetic differentiation of wasps originating from two common host—foodplant complexes, Manduca sexta L. on tobacco (“MsT”) and Ceratomia catalpae (Haworth) on catalpa (“CcC”). To test the hypothesis that C. congregata associated with these host—foodplant, complexes were genetically differentiated even where they occur in sympatry, we experimentally introduced tobacco at an established “catalpa site” for two consecutive years and compared wasps collected at this site with wasps collected from allopatric tobacco and catalpa sites in the mid-Atlantic region of North America. Using seven microsatellite loci and the mitochondrial COI locus, we found differences in microsatellite ...

Parasitoid reproduction is often limited by disposable time for accessing hosts or egg availability. In the case of synovigenic parasitoids (which mature eggs during their lifetime), theory predicts that egg limitation is infrequent because they are able to replenish their egg supply throughout life. However, this theory does not contemplate the effect of superparasitism on egg load. If superparasitism is applied as a strategy for modulating offspring sex ratio, as extra eggs are normally deposited in each host, it is to be expected that females experience egg limitation, especially when host density is high. In this article, the effect of host density on egg load, oviposition, and sex ratio in the tephritid parasitoid Diachasmimorpha longicaudata (Ashmead) was investigated. Specifically we analyzed the rate of oviposition per host and adjustments in offspring sex ratio in response to changes in host density and how these affect egg load. Parasitoids maintained a similar rate of oviposition, independent of host densities, except when host density fluctuated between 25 and 5 hosts per day. Females increased their oviposition rate and parasitism when confronted with 5 hosts, after having experienced a density of 25 hosts. Offspring sex ratio was biased in favor of females at high host density and with increasing prevalence of superparasitism. Results suggest that parasitoids have a strategy for maintaining high egg load in order to mitigate egg limitation, and for adjusting oviposition rate and offspring sex ratio with reference to previous oviposition experience.

The effects of the oviposition regime on egg maturation rate in the synovigenic parasitoid, Microplitis rufiventris Kokujev were investigated. In non-ovipositing wasps, females normally reach a peak of egg maturation rate on 1 d posteclosion. Egg maturation slowed down once the maximum oviduct egg load was reached on 2 d posteclosion. In wasps manipulated for 20 ovipositions per day, the egg maturation rate during the first 3 d posteclosion was lower compared with those manipulated for 40 ovipositions per day. The rate of egg maturation in 1-d-old wasps was found to be the highest for those that experienced 60 ovipositions per day. The maturation rate in females offered unlimited hosts was not significantly greater than those manipulated for 40 ovipositions per day. The act of oviposition significantly increased the rate of egg maturation and minimized egg resorption in the female wasp. The distribution of mature eggs in the ovaries at death is apparently associated with the oviposition regime. Trade-offs between egg maturation rate and female longevity were quite evident.

Habrobracon hebetor Say (Hymenoptera: Braconidae) is a gregarious ecto-parasitoid that attacks larvae of several species of Lepidoptera, mainly pyralid moths infesting stored products. Host quality strongly influences the reproductive success of the parasitoid. In this study, we assessed the reproductive performance of the parasitoid, H. hebetor in a series of laboratory experiments using six different pyralid host species: Indianmeal moth, Plodia interpunctella (Hübner), Mediterranean flour moth, Ephestia kuehniella (Zeller), almond moth, Ephestia cautella (Walker), rice moth, Corcyra cephalonica (Stainton), navel orangeworm, Amyelois transitella (Walker), and greater wax moth, Galleria mellonella L. Experiments were conducted using petri dishes (100 by 15 mm) as experimental arenas at 29 ± 1°C, 65 ± 5% relative humidity, and a photoperiod of 14:10 (L:D) h. Two-day-old H. hebetor females were introduced singly into experimental arenas and given a single host larva every day throughout their lifetime. The numbers of hosts paralyzed and parasitized, numbers of eggs laid each day on each host, egg-to-adult survivorship, and progeny sex ratio were used as parameters for assessing host suitability. Paralysis of hosts by H. hebetor females was significantly affected by host species. H. hebetor paralyzed >95% of the preferred host larvae that were offered and also used ≈90% of those for oviposition. Daily fecundity was highest on G. mellonella (22.1 ± 0.4) and C. cephalonica (21.6 ± 0.3), and lowest on E. cautella (13.4 ± 0.2). The egg-to-adult survivorship and progeny sex ratio were also significantly affected by the host species. The highest percentage of parasitoid survival was on A. transitella (75.7 ± 2.0) and C. cephalonica (75.4 ± 2.5), and lowest on G. mellonella (49.7 ± 4.8). Our studies clearly showed that H. hebetor females can paralyze and lay eggs on several pyralid species, but it cannot necessarily develop and reproduce optimally on all host species that it can paralyze and parasitize.

Lepidopteran erebid Zale phaeograpta (Hampson) has recently been found feeding on blackberry leaves (Rubus sp., cultivar “Tupi”) in two sites of Michoacan, Mexico. The life cycle and several life parameters of this insect, including parasitism, were examined in the laboratory. The egg, larva (seven instars), prepupa, pupa, and adult stages lasted 4.1, 35.9, 3.1, 14.5, and 29.1 d, respectively. Eggs are turquoise blue. The prolegs of first-instar larvae have an enlarged dark area that runs laterally. From second instar onwards, a whitish longitudinal dorsal band is observed along the entire body. Third-instar larvae wear a pair of dorsal protuberances in abdominal segment VIII. The fourth- and fifth-instar larvae are cream-colored, whereas sixth instars are entirely creamy. Pupa is covered with a waxy bloom. The apical margin of the forewings in males has two silvery bands, whereas in females, a dark band is present. Female and male pupae had the same weight (0.5 g) and measured 2.21 and 2.25 cm, respectively. The adult sex ratio of females to males was 1.1:1. The cumulative number of eggs laid by female during her lifetime was 281, with preoviposition and oviposition periods of 9.9 and 7.3 d, respectively. Maximum oviposition occurred 3.9 d after the start of oviposition (87.7 eggs per female). Larvae of Z. phaeograpta were parasitized by Microplitis sp. (Braconidae) (33%) and a currently unidentified Ichneumonidae species (9%), and pupae were parasitized by Brachymeria comitator (Walker) and another unidentified Brachymeria sp. (Chalcididae).

Original information on aphidiines parasitizing aphids on herbaceous and shrubby ornamental plants in southeastern Europe is presented. In total, 22 species are keyed and illustrated with scanning electron micrographs, stereomicroscope micrographs, and line drawings. The aphidiines presented in this work have been identified from 40 aphid taxa. Two hundred sixty-six aphidiine— aphid—plant associations are presented, out of which 126 are new. The results are discussed in relation to the overall parasitoid—aphid-plant associations in the area.

A review and illustrated key of the aphidiine parasitoids of Aphis ruborum (Börner and Schilder) are presented including their distribution. The parasitoid spectrum of A. ruborum in the West Palaearctic is rich, composed of Aphidius colemani Viereck, Aphidius matricariae Haliday, Binodoxys acalephae (Marshall), Binodoxys angelicae (Haliday), Ephedrus persicae Froggatt, Lipolexis gracilis Förster, Lysiphlebus confusus Tremblay and Eady, Lysiphlebus fabarum (Marshall), and Praon abjectum (Haliday), and supplemented by the introduction of Lysiphlebus testaceipes (Cresson). In the Americas the parasitoid complex of A. ruborum consists of A. colemani, Aphidius ervi Haliday (South America), and L. testaceipes (South and North America). Furthermore, the reservoir role of A. ruborum in various ecosystems was investigated in Europe (France) and South America (Chile). Faunal peculiarities and relationships of the parasitoid taxa are discussed together with a synopsis of their potential as biocontrol agents.

A new emerald ash borer (Coleoptera: Buprestidae) ectoparasitoid species, Spathius galinae Belokobylskij & Strazanac (Hymenoptera: Braconidae: Doryctinae), is described from the Russian Far East and South Korea. Molecular evidence supports that Russian and Korean specimens represent a single species and are closely related to two Asian species (S. agrili and S. generosus) that belong to the S. exarator species group. The morphological variation of adult S. galinae and its immature stages, distribution, life history, and relation to similar Asian Spathius species are discussed. The distribution of the new species may indicate this is one of the more cold hardy emerald ash borer parasitoids. A brief review of hymenopteran parasitoids of emerald ash borer and new host record, the first for Atanycolus nigriventris Vojnovskaja-Krieger (Braconidae: Braconinae), is reported.

This study encompasses three trophic levels, including description and observations of a butterfly caterpillar, its host plant, and two parasitoids, one of which is described here as a new species. We describe the immature stages and larval and adult behaviors of the butterfly Eryphanis greeneyi Penz & DeVries, 2008 (Lepidoptera: Nymphalidae) from the east Andean slopes of Ecuador. We identify Chusquea cf. scandens (Poaceae: Bambusoideae) as the larval food plant and review host associations in the genus Eryphanis and related taxa. We compare the morphology of E. greeneyi caterpillars to related taxa feeding on Chusquea and discuss the function of anal combs and associated frass throwing behavior. We describe a new species of braconid wasp Protapanteles eryphanidis sp. n. Whitfield and a tachinid fly, Winthemia sp. nr. analis, reared from field-collected larvae of E. greeneyi and evaluate their taxonomic position and association with E. greeneyi.

The New World microgastrine braconid wasp genus Venanus is reviewed, and a new illustrated key to species is provided. Three new species are described and illustrated: Venanus kusikuyllurae Rasmussen & Whitfield, n. sp., reared from the gelechiid pests of quinoa (Chenopodium quinoa Willdenow), Eurysacca quinoae Povolný, and Eurysacca melanocampta (Meyrick) in Peru; Venanus greeneyi Whitfield & Arias-Penna n. sp., reared from pyralid caterpillars feeding on Phenax rugosus (Poir.) and Boehmeria spp. (both Urticaceae) in Ecuador; and Venanus yanayacuensis Arias-Penna & Whitfield, n. sp., reared from pyralid caterpillars feeding on several species of Asteraceae in Ecuador. In addition, the female of Venanus helavai Mason, previously known only from males, is diagnosed and illustrated, and we provide the first known host record for this species: pyralid caterpillars on Myrsine coriacea (Sw.) (Myrsinaceae).

Although koinobiont parasitoids depend on their hosts for nutrition, they often exploit them in other ways during pupation. The solitary endoparasitoid Toxoneuron nigriceps Viereck (Hymenoptera: Braconidae) spins its cocoon in a chamber formed by its host Heliothis virescens (F.) (Lepidoptera: Noctudidae). The parasitoid prepupae depend on this host-formed pupation chamber; if left on an open surface, T. nigriceps larvae are unable to form a cocoon. To determine whether T. nigriceps larvae can form cocoons in artificial pupation chambers, common laboratory materials were tested for suitability. Test chambers included cotton balls, upright test tubes, gelatin capsules, and the wells of microtube racks. The proportion of parasitoids that formed cocoons in each chamber, as well as the proportion that survived to adulthood, were recorded and compared with each other and to those placed in host-formed chambers, as well as to those placed in petri dishes, a flat surface. Parasitoid larvae were able to spin cocoons in all artificial chambers that provided a small, partially enclosed space. The proportion of parasitoids that formed cocoons was largest in cotton balls, but no chambers (other than petri dishes) were significantly different from the host formed control. The proportion of parasitoids that survived to adulthood was significantly smaller in the petri dish and test tube treatments than in the control. Due to the high success rate for cocoon formation and survival, as well as practicality in a mass-rearing situation, gelatin capsules and microtube rack wells were considered the best choices for use as artificial pupation chambers among those tested.

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is both heteroecious and holocyclic, seasonally alternating between buckthorn (Rhamnus spp.), (the primary, overwintering host) and soybean, Glycine max (L.) Merr. (the secondary host). Recently, a classical biological control program for this invasive pest has been implemented in North America using the Asian aphidiine braconid wasp Binodoxys communis Gahan. Two critical, related questions regarding the overwintering biology of B. communis are 1) does the parasitoid maintain fidelity to A. glycines throughout the aphid life cycle and follow it to its primary host; and, if it does, 2) is parasitoid migration facilitated by phoretic movement within buckthorn-specific winged aphids? In the laboratory, we compared B. communis parasitism on several different autumnal morphs of A. glycines: winged gynoparae (fall migrants) and their oviparous offspring on buckthorn, fourth-instar alatoid nymphs that would form either gynoparae or summer migrants on soybean, and third-instar gynoparous alatoid nymphs on soybean. We also introduced gynoparae and B. communis onto caged buckthorn plants in southeastern Minnesota to examine autumnal parasitism under natural conditions. In both the laboratory and field, parasitism rates of oviparae were much higher than those of gynoparae. In addition, B. communis rarely completed development on fourth-instar alatoid nymphs. Although wasps successfully developed on third-instar gynoparous nymphs, these hosts mummified before forming wings. These results suggest that although at least one buckthorn-specific morph of A. glycines seems suitable for B. communis parasitism, it is unlikely that alate-mediated dispersal of immature parasitoids is an adaptive strategy to locate Rhamnus in this species.

Laboratory experiments were conducted to determine the effect of host instar and feeding status on the egg load of early life stage in Microplitis rufiventris Kokujev (Hymenoptera: Braconidae), a solitary koinobiont endoparasitoid of some noctuid pests. The wasps that developed from fourth or fifth instars of Spodoptera littoralis (Boisduval) larvae were heavier in weight than those from earlier stages. Different numbers of mature eggs were found in the two ovaries of the female wasp. Egg loads, corresponding to fitness, were significantly influenced by female weight and feeding status. However, the interactions between the two treatment factors were not significant. The average number of mature eggs carried by females at eclosion time ranged from 52 eggs in smaller wasps to 62 eggs in larger wasps. Females that were fed had higher egg loads and egg maturation rate than unfed females. However, female wasps were capable of maturing considerable number of eggs without feeding; suggesting that they produce a certain portion of eggs from nutritional reserves that had been stored during larval stage. Female wasps are weakly synovigenic, with an egg maturation at a rate of ≈1.8 eggs per h. Further investigation is required to verify the rate of egg maturation and eventually egg resorption in different stages of adult female M. rufiventris.

To better understand the phylogeography of Rhagoletis flies in the cingulata species group, we conducted a seven year host plant survey in México, behavioral observations, and studies on the basic biology of these tephritids. The survey revealed the existence of two geographically isolated Rhagoletis cingulata (Loew) populations in México. The first population was found to be restricted to Prunus serotina ssp. capuli (Cav.) McVaugh in an area within the central dry Altiplano spanning from Tlaxcala to México City and neighboring parts of the States of México, Puebla, and Hidalgo. The second population was found to infest Prunus serotina ssp. virens (Wooton & Standl.) McVaugh in high elevation areas of northeastern México between San Luis Potosí and Coahuila along the Sierra Madre Oriental. Both populations were hosts to the parasitoid Diachasmimorpha mellea (Gahan) (Hymenoptera: Braconidae), with percentage parasitism varying across sites. Collections of P. s. ssp. capuli and Prunus serotina Ehrh. ssp. serotina across the Eje Volcanico Trans Mexicano, the Sierra Madre del Sur, the Sierra de los Altos de Chiapas and mesic areas of the Sierra Madre Oriental between Veracruz and Queretaro failed to yield any pupae. Sites where pupae were recovered were significantly dryer than sites where R. cingulata was not found. Recovered flies were found to be univoltine and to overwinter as pupae. Adults in the field in Tlaxcala (Central Altiplano) were mainly sighted guarding, mating, and ovipositing in green fruit. Larval yield of fruit collected outside the natural area of distribution, and exposed to flies in the laboratory, was significantly lower than that of fruit collected within the natural range of R. cingulata. We compare distribution patterns with those of other species in the genus and discuss hypotheses to explain the outcome.

One of the fundamental questions in evolutionary ecology seeks to understand how new biodiversity is created and structured into communities. The apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), a model for rapid ecological speciation via host plant shifting for phytophagous insects, and its parasitoid community can offer insight into answering this and other related questions. Speciation of Rhagoletis also seems to be driving sequential speciation in a host specific parasitoid wasp Diachasma alloeum (Muesebeck) (Hymenoptera: Braconidae). However, biological and geographic information regarding D. alloeum and other parasitoids attacking flies in the genus Rhagoletis is sorely lacking, a problem that complicates the study of their evolution. Here, we present a synthesis of the geographic ranges and extended host associations of Rhagoletis-attacking parasitoids and test whether parasitoids can overlap in host use. In particular, we ask whether 1) wasps that co-occur in sympatry attack different life stages of the fly, 2) locally co-occurring wasps share some fly species in common but not others, 3) wasps differ in local abundance on those fly hosts they share in common, and 4) wasps vary on a regional scale in their geographic distributions. We use both collections and published records to answer the above-mentioned questions. A strong understanding of the Rhagoletis-attacking parasitoid distributions will facilitate future study of sequential radiation in this system.

Carbohydrate energy sources are known to be important for many adult parasitic wasps. Floral visitation is commonly observed, and in many groups specialized mouthpart morphology is associated with deep nectar extraction. In parasitic wasps, there are few data examining the relationship between host plant use and the length of the mouthparts. In an effort to associate mouthpart length to nectar source, pollen was identified from museum specimens of selected species of Agathirsia (Hymenoptera: Braconidae). Despite drastic differences in glossa length, the pollen of several species of Asteraceae were commonly found on specimens of various species. We infer that increased feeding efficiency, as opposed to nectar access, is the adaptive value of elongate glossae in Agathirsia. Species with short mouthparts, however, exhibited a difference from both the medium and long mouthpart categories in pollen similarity. This suggests that members of Agathirsia with elongated mouthparts are more apt to visit certain flowers compared with short-tongued species. Males and females exhibited considerable overlap of their common nectar sources and displayed similar pollen richness. Pollen richness was higher in species in the medium length category compared with the short category, but these results are confounded by the fact that the medium-length specimens were on average larger bodied.

A new species of Minanga Cameron (Hymenoptera: Braconidae: Sigalphinae), Minanga brevicarinata Tan & Chen, sp. nov., from China is described and illustrated, Previously known mainly from the Afrotropical region (eight species), with one species recently described from the Nearctic region, the genus is recorded for the first time from the boundary of Palearctic and Oriental regions. A new subgenus, Anopliminanga subgen. nov., is proposed to include two species (Minanga achterbergi Sharkey and Minanga brevicarinata sp. nov.). A key to species of the genus Minanga is updated. The distribution of Minanga and the new subgenus are briefly discussed.

A review and illustrated key of the aphidiine parasitoids of Greenideinae aphids is presented including their distribution. Fissicaudus thailandicus Starý & Rakhshani sp. nov. from Thailand is described and figured. Parabioxys songbaiensis Shi & Chen is redescribed based on reared specimens from North Korea. Faunal peculiarities and relationships of the taxa are discussed together with a synopsis of their potential as biocontrol agents.

The development of parasitoid wasps is dependent on the finite resources contained in a single item of resource (=host) that is frequently not much larger than the adult parasitoid. When the costs of egg production are high, and host distribution is highly aggregated, parasitoid females may spend prolonged periods guarding their eggs and host resources as an adaptive strategy to optimize their inclusive fitness. Here, we examine aggressive interactions between the females of the secondary hyperparasitoid Trichomalopsis apanteloctena (Crawford) (Hymenoptera: Chelonidae), for control of cocoon clusters of their primary parasitoid host Cotesia kariyai (Watanabe) (Hymenoptera: Braeonidae). Generally, larger female hyperparasitoids were more successful at defending cocoon clusters than smaller female hyperparasitoids. However, when first encountering host cocoons, larger females behaved more aggressively toward conspecific wasps than smaller females. After occupation of a host cocoon cluster, females of similar size rarely engaged in physical combat, but both females primarily exhibited threatening behavior toward each other. However, larger females usually displaced smaller females which had initially occupied cocoon clusters. Some small females chewed through the outer cocoon silk layer to avoid being displaced by larger females and these wasps were able to continue parasitizing cocoons of C. kariyai. Extended bouts of aggression tended to reduce the number of eggs laid by the guarding female because of disruption of oviposition behavior. The relationship between the size of host cocoons and body mass in T. apanteloctena was also examined. The size of hyperparasitoid progeny was strongly correlated with host size. However, the relationship between maternal size, the number of matured eggs in her ovarioles and body mass in her offspring was not significant.

The nontarget effects of the plant growth regulator indol-3-acetic acid (IAA) on parasitoid development and reproduction were examined using the endoparasitoid Apanteles galleriae Wilkinson (Hymenoptera: Braconidae). The effects of IAA were assessed by rearing A. galleriae on hosts fed different doses of the growth regulator and then measuring a range of life history traits such as immature developmental time, adult longevity, body size, fecundity, and sex ratios in F1 and F2 generations. Wasp development from egg to adult took 27–47 d. However, adult emergence of parasitoids reared on hosts exposed to IAA doses required 14–24 d longer than controls to complete development at doses >200 ppm. Longevity of IAA-treated adult wasps was lower than that of controls at any dose. For example, at IAA doses >200 ppm, the life span of both male and female adult wasps decreased >50% compared with parasitoids that developed inside IAA-free hosts. Adult length also decreased at 500 and 1,000 ppm with respect to the control and lesser dosages. The total number of progeny decreased >50% and female sex ratio increased at doses >200 ppm compared with controls. Our results showed that the developmental biology of parasitoids exposed indirectly to IAA might be affected by high doses.