可疑柄瘤蚜茧蜂对高温下不同龄期黑豆蚜的寄生及其适合度表现

研究寄生蜂对寄主不同龄期的寄生策略通常采用适温下（≈25℃）培养的寄主进行试验。 为探究蚜茧蜂对高温下生长的寄主蚜虫的寄生反应及其适合度表现,在30℃条件下饲养寄主孤雌胎生无翅黑豆蚜Aphis fabae Scopli,获得不同龄期若蚜和刚羽化的成蚜,分别提供给可疑柄瘤蚜茧蜂Lysiphlebus ambiguous Haliday寄生,观察蚜茧蜂的寄生率以及后代性比、体型大小和发育时间等适合度相关特性。结果表明： 可疑柄瘤蚜茧蜂对1至4龄若蚜及成蚜均寄生,但偏向寄生较早龄期的若蚜,对成蚜的寄生率为28.0％,显著低于对1龄（400％）和2龄（42.8%）寄主若蚜的寄生率。后代雌蜂比例和体型随寄主龄期（体型）增大而减小,而发育历期则呈现“中间低,两头高”的格局。后代性比、体型大小及发育历期等适合度表现与此前适温（≈25℃）下得到的结果截然相反。因此推测,寄主黑豆蚜体型或龄期可能不是或不全部是可疑柄瘤蚜茧蜂评价寄主质量的依据,其他与寄主蚜虫内共生菌动态相关的线索（如行为的,化学的等）可能才是其评价寄主质量的依据。     

Larval anatomy and structure of absorbing epithelia in the aphid parasitoid Aphidius ervi Haliday (Hymenoptera, Braconidae)

The present work describes Aphidius ervi Haliday (Hymenoptera, Braconidae) larval anatomy and development, focusing on time-related changes of body structure and cell ultrastructure, especially of the epithelial layers involved in nutrient absorption. Newly hatched 1st instar larvae of A. ervi are characterised by gut absence and a compact cluster of cells makes up their body. As the parasitoid larva develops, the central undifferentiated cell mass becomes hollowed out, leading to the formation of gut anlage. This suggests that absorption of nutrients at that stage may take place through the body surface, as more directly demonstrated by the occurrence on the epidermis of proteins associated with transepithelial transport, such as Na(+)/K(+)-ATPase and alkaline phosphatase (ALP). Second instar larvae show the presence of the gut with a well-differentiated brush border and a peritrophic membrane. Gut cells are filled by masses of glycogen granules and lipid droplets. The tracheal system starts to be visible. The haemocoel becomes evident in late 2nd instar, and contains large silk glands. Mature 3rd instar larvae are typically hymenopteriform. The midgut accounts for most of the body volume and is actively involved in nutrient absorption, as indicated by the well developed brush border and by the presence of Na(+)/K(+)-ATPase and ALP on the basolateral and luminal membrane respectively. At this stage, large lipid droplets have gradually replaced the cellular glycogen stores in the midgut cells. The tracheae are completely differentiated, but their internal lumen still contains fibrillar material, suggesting that they are not functional as long as host fluids bath the parasitoid larva. In late 3rd instar larvae, silk glands, structurally similar to Malpighian tubules, show a very intense vesicular traffic toward the internal lumen, which, eventually, results in being filled by secretion products, suggesting the possible recycling of metabolic waste products during mummy formation.     

Temporal genetic structuring of a specialist parasitoid,Lysiphlebus hirticornis Mackauer (Hymenoptera: Braconidae) attacking a specialist aphid on tansy

In insect species characterized by inbreeding, limited dispersal, and a metapopulation structure, high genetic differentiation and reduced genetic diversity within local populations are expected. Using the model system Lysiphlebus hirticornis Mackauer, a specialist parasitoid of the tansy aphid, Metopeurum fuscoviride Stroyan (Hemiptera: Aphididae), we examined within‐site temporal population dynamics and genetics, including molecular variation at the tansy plant level. Aphid‐parasitoid dynamics were surveyed and parasitoids sampled from 72 tansy plants at 11 sites in and around Jena, Germany, over one growing season. Thereafter, parasitoid samples were genotyped at 11 polymorphic microsatellite loci. Colonization, extinction, and recolonization events occurred during the season. Allele numbers and identities were highly variable over time. When samples from all sites were pooled, allele number over all loci showed a decreasing trend with time. At the level of sites, temporal changes in genetic diversity were more variable. Analysis of molecular variance revealed that samples at the plant level explained the highest variance compared to at site level. We conclude that the genetic structuring of this insect is very fine grained (i.e. at the tansy plant level) and the temporal genetic diversity is explained by a combination of extinction and recolonization events, as well as inbreeding. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 737–749.     

Potential effects of plant protease inhibitors, oryzacystatin I and soybean Bowman-Birk inhibitor, on the aphid parasitoid Aphidius ervi Haliday (Hymenoptera, Braconidae)

Protease inhibitors (PIs) have been shown to cause lethal and sublethal effects on aphids depending on the kind of PI and aphid species. Therefore, these proteins might affect aphid parasitoids directly by inhibiting their digestive proteolysis or indirectly via their development in a less suitable host. In our study, the risk of exposure and the potential effects of soybean Bowman-Birk inhibitor (SbBBI) and oryzacystatin I (OCI) on the aphid endoparasitoid Aphidius ervi were investigated using artificial diet to deliver PIs. Immunoassays showed that both SbBBI and OCI were detected in the honeydew of aphids reared on artificial diet containing these recombinant proteins at 100 microg/mL. However, only SbBBI was detected in parasitoid larvae, while this PI could not be detected in adult parasitoids emerged from PI-intoxicated aphids. Enzymatic inhibition assays showed that digestive proteolytic activity of larvae and adults of A. ervi predominantly relies on serine proteases and especially on chymotrypsin-like activity. Bioassays using SbBBI and OCI on artificial diet were performed. A. ervi that developed on intoxicated aphids had impaired fitness. Thus development and parasitism success of parasitoids exposed to OCI were severely affected. On the contrary, SbBBI only altered significantly female size and sex ratio. Direct exposure to PIs through adult food intake did not affect female's longevity, while SbBBI and OCI (100 microg/mL) induced 69% and 30% inhibition of digestive protease activity, respectively. These studies made it possible to estimate the risk of exposure to plant PIs and the sensitivity of the aphid parasitoid A. ervi to these entomotoxins, by combining immunological, biochemical and biological approaches. First it pointed out that only immature stages are affected by PIs. Secondly, it documented two different modes of effect, according to the nature of the PIs and both host and parasitoid susceptibility. OCI prevented the development of A. ervi mainly due to the host susceptibility, whereas SbBBI only induced sublethal effects on the parasitoid, possibly due to both direct action on the parasitoid susceptible proteases, and host-mediated action through size reduction.     

Quality of different aphids as hosts of the parasitoid Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae, Aphidiinae)

Lysiphlebus testaceipes (Cresson) has a broad aphid host range; however the quality of these preys may interfere in its biological feature. This study aimed to evaluate the quality of three Macrosiphini, Brevicoryne brassicae (L.), Lipaphis erysimi (Kaltenbach) and Myzus persicae (Sulzer), and three Aphidini Schizaphis graminum (Rondani) Rhopalosiphum maidis (Fitch) and Aphis gossypii Glover as hosts to L. testaceipes and to determine the relation possible of host preference, of size and quality of the host. The tests were carried out in climatic chamber at 25 +/- 1 degrees C, RH 70 +/- 10% and 12h photophase. The parasitoid did not oviposite in B. brassicae and L. erysimi, while the other species were nutritionally suitable to the parasitoid. L. testaceipes showed preference for aphids from tribe Aphidini and these hosts presented better quality to the parasitoid when compared to Macrosiphini. Interactions among size, preference and quality between the Aphidini were found. L testaceipes showed preference (parasitism rate 76.7%) for R. maidis, the bigger host (hind tibia with 0.281 mm). This host provided bigger size (hind tibia with 0.49 mm) and higher emergence rate (95.6%) to the parasitoid when compared to A. gossypii (parasitism rate of 55.7%). Also the smaller host A. gossypii (0.266 mm) provided smaller size hind tibia (0.45 mm) and higher mortality of the parasitoid (emergence rate 72.1%). However, the development time was shorter and the longevity was higher in A. gossypii (6.3 and 5.4 days, respectively) when compared to the host R. maidis (6.7 and 3.8 days, respectively), and not been related to host size.     

Microsatellites from Lysiphlebus hirticornis Mackauer (Hymenoptera: Braconidae), a specialist primary parasitoid attacking the specialist tansy aphid, Metopeurum fuscoviride Stroyan (Hemiptera: Aphididae)

Nine polymorphic microsatellite loci were isolated from the specialist aphid parasitoid, Lysiphlebus hirticornis. In addition, two published loci from closely related Lysiphlebus species were also used. Allelic diversity and heterozygosity were quantified in samples collected from eight tansy plants growing in an area of approximately 150 m² in Jena, Germany.     

Effects of feeding frequency and sugar concentration on behavior and longevity of the adult aphid parasitoid: Aphidius ervi (Haliday) (Hymenoptera: Braconidae)

The effectiveness of the predatory mite, Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseidae), as a suppressive agent of the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), was evaluated on greenhouse ivy geraniums at predator:prey release ratios of 1:60, 1:20, and 1:4. Releases at each predator:prey ratio were made at moderate and high T. urticae densities to determine if initial pest population size influenced the suppressive ability of the predator. At ratios of 1:4 and 1:20, P. persimilis significantly reduced T. urticae populations 1 week after release and kept them at low levels thereafter. Plant damage also was significantly reduced at these densities. After 4 weeks, the P. persimilis that were released at a ratio of 1:4 consistently reduced T. urticae populations from densities as high as 30 T. urticae per leaf to fewer than 0.6 per leaf. We found no interaction between release ratio and T. urticae density, indicating that predator effectiveness remains constant, at least within the range of T. urticae densities used. Our work demonstrates the potential of P. persimilis to provide effective control of T. urticae on a greenhouse-grown floricultural crop at a moderately low predator:prey ratio (1:20) and over a range of initial pest densities. However, we recommend that P. persimilis be released at a ratio of 1:4 for greatest reliability and successful control of T. urticae on ivy geraniums.     

Comparative selectivity of pesticides used in greenhouses,on the aphid parasitoid Aphidius colemani (Hymenoptera: Braconidae)

A series of bioassays were conducted under laboratory conditions to determine the relative toxicities of various pesticides (acetamiprid, cypermethrin, chlorantraniliprole and emamectin benzoate, Bacillus thuringiensis var. kurstaki and Helicoverpa armigera nucleopolyhedrovirus, copper oxychloride, iprodione, mandipropamid, a mixture of propamocarb?+?fluopicolide and mixture of fludioxonil?+?cyprodinil) on Aphidius colemani adults and mummies, as well as sublethal effects on female fecundity. Cypermethrin was highly toxic to pupa of A. colemani within host mummies. Acetamiprid, cypermethrin, emamectin benzoate, a mixture of propamocarb?+?fluopicolide and mixture of fludioxonil?+?cyprodinil were also highly toxic to A. colemani adults (92–100% mortality at 48?h post treatment). Mandipropamid, iprodione and copper oxycloride treatments significantly reduced fecundity of the female parasitoids. In contrast B. thuringiensis var. kurstaki, H. armigera nucleopolyhedrovirus and chlorantraniliprole were harmless (<30% mortality) to the parasitoid species tested according to International Organisation for Biological Control toxicity classification and are likely to be compatible with integrated pest management programmes.     

Singing on the wings! Male wing fanning performances affect female willingness to copulate in the aphid parasitoid Lysiphlebus testaceipes (Hymenoptera: Braconidae: Aphidiinae)

Lysiphlebus testaceipes (Hymenoptera: Braconidae: Aphidiinae) is a generalist endoparasitoid attacking more than 100 aphid species. In L. testaceipes, wing fanning is a main male courtship display evoked by a female‐borne sex pheromone. However, no information is available on the characteristics and behavioral role of male fanning during courtship in this parasitoid. Here, the courtship behavior of a wild strain of L. testaceipes was quantified and the male wing fanning performances were analyzed through high‐speed video recordings and examined in relation to mating success. Courtship sequence of wild L. testaceipes did not substantially differ from that previously reported for other populations mass reared on aphids. We observed that the male courtship duration did not affect mating success. However, video analysis revealed that the males producing high‐frequency fanning signals achieved higher mating success over those that display low‐frequency fanning. Wing fanning before successful and unsuccessful courtship differed in amplitude of wing movements and alignment toward the mate, highlighting that frontal courtship positively influence the female mating decisions. This study increases knowledge on sexual behavior in a key parasitoid of aphids, highlighting the importance of wing fanning among the range of sensory modalities used in the sexual communication of L. testaceipes. From a practical point of view, this information is useful in L. testaceipes‐based biocontrol strategies, since it can help to establish parameters for quality checking of mass‐reared wasps over time.     

Effects of artificial diet containing GNA and GNA-expressing potatoes on the development of the aphid parasitoid Aphidius ervi Haliday (Hymenoptera: Aphidiidae)

Aphid parasitoids are important biological control agents. The possibility arises that whilst foraging on insect-resistant transgenic plants, they are themselves at risk from direct and indirect effects of the expression of a transgene used to control the pest species. A liquid artificial diet was successfully used to deliver the snowdrop lectin (Galanthus nivalis agglutinin; GNA) to the peach-potato aphid, Myzus persicae. Bioassays utilising artificial diet incorporating GNA, and excised leaves of the GNA-expressing transgenic potato line, GNA2#28, were performed to assess the potential effects of GNA on the development of the aphid parasitoid Aphidius ervi. The results indicate that GNA delivered via artificial diet to the aphids can be transferred through the trophic levels and has a dose-dependent effect on parasitoid development. Parasitoid larvae excreted most of the ingested GNA in the meconium but some of it was detected in the pupae. Although A. ervi development was not affected when developing within hosts feeding on transgenic potato leaves, this probably reflected sub-optimal expression of the toxin in the transgenic potato line used     

Male wing fanning by the aphid parasitoid Aphidius ervi (Hymenoptera: Braconidae) produces a courtship song

We, herein, report evidence that wing fanning by the aphid parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) constitutes a courtship song. Complete removal of the forewings or only the distal half of them reduced male copulation success in comparison to intact males. Males that achieved copulation within the observation period produced wing fanning at a higher rate than males that did not copulate. Playback of wing fanning sound altered the behaviour of virgin females, increasing the time they devoted to grooming, as compared with subjects that were exposed to silence or white noise. Our findings contribute to the understanding of the acoustic dimension of the sensory modalities employed by this aphid parasitoid in sexual signalling.     

Consequence of emergence pattern on inbreeding risk in the aphid parasitoid Aphidius matricariae (Hymenoptera: Braconidae)

In insect parasitoids, mating strategy depends on mate availability and is influenced by the spatial and temporal emergence patterns of adults. For quasi-gregarious species, simultaneous emergence favors local mating and reduces search costs for partners while increasing the risk of inbreeding, particularly when only one female parasitizes the initial host patch. Consequently, in inbreeding sensitive species, mating on the place of adult emergence (patch mating) between siblings should be counter selected. In practice, the timing of male and female emergence and of their dispersal influences mate availability and can limit on patch mating. To test the role of these two factors, we analyzed the daily distribution of emergence and patch residence time of a cohort in the aphid parasitoid Aphidius matricariae (Hymenoptera: Braconidae). We observed that adult emergence is concentrated on the morning with males emerging on average before females with some overlaps. A more precise evaluation of emergence pattern within a brood suggests that brothers and sisters rarely emerge at the same time and rapid dispersal of males and females favors off-patch mating. The relationships between timing of emergence including differences between sex and consequences on inbreeding probability in these species are thus discussed.     

Quality of different aphids species as hosts for the parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae: Aphidiinae)

The suitability of Macrosiphum euphorbiae (Thomas), Aulacorthum solani (Kaltenbach) and Acyrthosiphon kondoi Shinji (Hemiptera: Aphididae) as hosts for the aphid parasitoid Aphidius ervi Haliday was evaluated by assessing host size, host preference, and host quality. Tests were carried out in an environmental chamber at 22±1oC, 70±10% RH and 12h photophase. Replicates (11) consisted of one 24h-old mated female of A. ervi without a previous oviposition experience. Female was released into a Petri dish (5 cm) with 20 2nd and 3rd instars of one of each aphid species tested on a leaf disc of the host plant onto a 1% water-agar layer. Parasitoid emergency was lower in A. kondoi (78.7%) compared to M. euphorbiae (92.2%) and A. solani (91.7%). Acyrthosiphon kondoi (0.36 mm) was the smallest host. The parasitoid showed preference (74.0% parasitism) for M. euphorbiae, the largest host (hind tibia length=0.73 mm), which in turn yielded larger A. ervi females (0.75 mm).     

Influence of nutrient deficiency caused by host developmental arrest on the growth and development of a koinobiont parasitoid

Koinobiont parasitoids utilize nutrients obtained from hosts that contine to feed and grow after parasitization. However, if the ecdysis of early host instars is prevented, parasitized larvae will fail to grow large enough to support the development of the parasitoid brood and both organisms will perish. When L5 instar larvae (the penultimate stage) of Pseudaletia separata were parasitized by Cotesia kariyai and injected with Euplectrus separatae venom (5PV), the development of these hosts was arrested before molting to the next stage and the caterpillars thus failed to gain weight. These hosts remained at approximately 300 mg until parasitoid emergence. In contrast, hosts parasitized as L5 but without the injection of venom (5P) exhibited an increase in weight after molting to the next stage and ultimately grew to approximately 700 mg. The inhibition of ecdysis reduced the amount of food resource (e.g. fat body) for the parasitoid larvae. On the other hand, when final (= L6) host instars were parasitized and injected with E. separatae venom (6PV), the maximum weight attained by these larvae was about 710 mg, although weight gain was depressed compared to hosts parasitized without the injection of E. separatae venom (6P). The adult weight of C. kariyai that emerged from 5PV hosts was less than conspecifics that emerged from 5P, 6P, and 6PV respectively, although the egg-pupal period of the parasitoid from 5PV hosts was extended. The offspring sex ratio (percentage males) of adult wasps did not vary significantly with treatment. Female parasitoids that eclosed from 5PV hosts laid almost the same number of eggs in day 0-6th host instars as those emerging from 5P, 6P, 6PV hosts. Their egg-pupal period was extended and the cocoon cluster mass and the parasitoid body mass on subsequent generations was lighter than those reared from 5P, 6P, 6PV hosts. The sex ratio of F2 C. kariyai wasps that eclosed from 5PV increased more than in wasps that eclosed from the other host treatments (5P, 6P, 6PV). Our results reveal that a reduction in host quality and offspring fitness in the first generation negatively impacted female fitness in the second generation. An early arrestment of host growth, mediated by the addition of E. separatae venom, has severe implications on parasitoid fitness by reducing host quality, especially in smaller hosts.     

Influence of host behavior and host size on the success of oviposition ofCotesia urabae andDolichogenidea eucalypti (Hymenoptera: Braconidae)

Behavioral interactions among Cotesia urabaeAustin and Allen, Dolichogenidea eucalyptiAustin and Allen (Hymenoptera: Braconidae), and their host Uraba lugensWalker, the gum leaf skeletonizer (Lepidoptera: Noctuidae), were observed at three host sizes over a 20-min period. These sizes were first instar (small, gregarious), fourth-fifth instar (mid, gregarious), sixth-seventh instar (large, solitary) larvae. Unlike C. urabae, D. eucalyptiused its legs to hold small larvae before ovipositor insertion. D. eucalyptialso visited patches of small larvae more frequently, proceeded less often through patches of mid larvae, and made significantly fewer ovipositions in mid and large larvae. Small larvae responded to both parasitoids by dispersing outward, while mid larvae responded to parasitoids by moving inward to form a denser group. Larvae reared or thrashed after each parasitoid visit, especially mid larvae, and some continued to do so for up to 2h after parasitoid departure. Mid and large larvae occasionally injured parasitoids by biting their appendages. By rearing or thrashing immediately prior to an encounter with a parasitoid, mid and large larvae decreased the likelihood of being parasitized by up to 50%.     

The influence of temperature on size as an indicator of host quality for the development of a solitary koinobiont parasitoid

The influence of aphid size on the host quality assessment and progeny performance of aphidiine parasitoids was examined using the mealy plum aphid parasitoid, Aphidius transcaspicus Telenga (Hymenoptera: Braconidae) and the black bean aphid, Aphis fabae Scopoli (Homoptera: Aphididae), as a readily acceptable alternate host. Aphid size in relation to stage of development was manipulated by rearing synchronous aphid cohorts at either 15 or 30 °C. At 15 °C, 2nd instar aphids were approximately the same size as 4th instar aphids reared at 30 °C. Cohorts of 30 aphids from each instar, reared at each temperature, were exposed to parasitism by a single parasitoid female for a period of 5 h. Overall susceptibility to parasitism did not vary between aphid cohorts, but the parasitoid response to aphid size differed significantly between rearing temperatures for both progeny sex ratio (parent female assessment of host quality) and larval growth and development (host suitability for parasitoid development). For aphids reared at 15 °C, the proportion of female progeny and emerging adult size for the parasitoid increased linearly with aphid size at the time of attack, while development time remained constant. In contrast, for aphids reared at 30 °C, the proportion of female progeny, emerging adult size, and the development time of the parasitoid all declined with aphid size at the time of attack. The contrasting responses of the parasitoid to host size for aphids reared at the two temperatures suggest that host quality is only indirectly related to aphid size among aphidiine parasitoids. The possible effects of higher temperatures on nutritional stress, obligate endosymbionts, and future growth potential of the aphids are discussed as explanations for the variation in host quality for parasitoid development.     

Sucrose octanoate toxicity to brown citrus aphid (Homoptera: Aphididae) and the parasitoid Lysiphlebus testaceipes (Hymenoptera: Aphidiidae)

We report the toxicological effects of a new biorational, synthetic sucrose octanoate (AVA Chemical Ventures L.L.C., Portsmouth, NH), on brown citrus aphid, Toxoptera citricida (Kirkaldy), nymphs and adults and to its native parasitoid Lysiphlebus testaceipes (Cresson). Sucrose octanoate topically applied was equally toxic to brown citrus aphid adults and nymphs with LC50 and LC90 values ranging from 356 to 514 and 1029 to 1420 ppm, respectively. Mortalities of both stages did not differ significantly over time during the 3-24-h sampling period. Dry residues of sucrose octanoate exhibited similar levels of toxicity to both nymphs and adults. Mortality ranged from 60 to 70% at 6,000 ppm 4 h after exposure. L. testaceipes was not harmed by treatments as high as 4,000 ppm of sucrose octanoate as long as the parasitoid had mummified before treatment. Based on these results, sucrose octanoate would be a useful biorational in citrus integrated pest management programs.     

Evaluation of the establishment of Aphidius ervi Haliday (Hymenoptera: Braconidae) in lucerne aphid populations in New South Wales

The aphid parasitoid Aphidius ervi was released in the major lucerne-growing areas of New South Wales (NSW), Australia, between 1978 and 1981. With the collaboration of district agronomists of the New South Wales Department of Agriculture, five State-wide surveys were conducted in 1982–1983 to determine the success of the release program. In each survey, the distribution of the parasitoid was checked in relation to populations of the aphids Acyrthosiphon kondoi Shinji and Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). The surveys confirmed the successful dispersal and establishment of A. ervi in the major lucerne-growing areas of NSW. They demonstrated its ability to survive and recover rapidly after a severe and widespread drought.     

Impact of Rag1 aphid resistant soybeans on Binodoxys communis (Hymenoptera: Braconidae), a parasitoid of soybean aphid (Hemiptera: Aphididae)

Multiple strategies are being developed for pest management of the soybean aphid, Aphis glycines Matsumura; however, there has been little published research thus far to determine how such strategies may influence each other, thereby complicating their potential effectiveness. A susceptible soybean (Glycine max L.) variety without the Rag1 gene and a near isogenic resistant soybean variety with the Rag1 gene were evaluated in the laboratory for their effects on the fitness of the soybean aphid parasitoid, Binodoxys communis (Gahan). The presence or absence of the Rag1 gene was verified by quantifying soybean aphid growth. To test for fitness effects, parasitoids were allowed to attack soybean aphids on either a susceptible or resistant plant for 24 h and then aphids were kept on the same plant throughout parasitoid development. Parasitoid fitness was measured by mummy and adult parasitoid production, adult parasitoid emergence, development time, and adult size. Parasitoids that attacked soybean aphids on susceptible plants produced more mummies, more adult parasitoids, and had a higher emergence rate compared with those on resistant plants. Adult parasitoids that emerged from resistant plants took 1 d longer and were smaller compared with those from susceptible plants. This study suggests that biological control by B. communis may be compromised when host plant resistance is widely used for pest management of soybean aphids.