Specialist Parasitoid Research Articles

Complementary suppression of aphids by predators and parasitoids

Biocontrol practitioners have long debated the relative merits of specialist parasitoids versus generalist predators as biological control agents. Predators and parasitoids exhibit a broad array of ecological differences that might lead them to play different, and perhaps complementary, roles in pest suppression. However, predators often feed on parasitoids with the potential to disrupt biological control. We compared suppression of the woolly apple aphid (Eriosoma lanigerum) when attacked solely by the specialist parasitoid Aphelinus mali, to aphid suppression when the parasitoid was joined by a diverse community of generalist predators (primarily earwigs, syrphids, predatory bugs and spiders). In a series of exclusion-cage experiments conducted on apple trees (Malus domestica) placed in the field, we found that the parasitoid alone significantly slowed aphid population growth. However, consistently flat or declining aphid densities were seen only when the parasitoid was paired with the generalist predator guild. This suggested that predators and parasitoid exerted complementary impacts, with the most effective aphid suppression achieved when the two natural enemy classes were present together. Consistent with this observation, percentage aphid parasitism was not consistently reduced in the presence of predators; this implies relatively weak predator–parasitoid interference. Altogether, our results suggest that the conservation of a diverse community of natural enemies, including both predators and parasitoids, is an effective way to strengthen suppression of this, and perhaps other, aphid species.

Arms race between leaf rollers and parasitoids: diversification of plant‐manipulation behavior and its consequences

Understanding the determinants of community structure remains a challenging ecological task; the plant–host insect–parasitoid community is a particularly important community because of its overwhelming biomass in terrestrial ecosystems. Some ecological and phylogenetic factors are determinants of community structure; however, the relative importance of these factors remains to be entirely elucidated because we cannot separately analyze individual factors. Here, we compared parasitoid communities among 23 weevil species. We demonstrated that the parasitoid community structures were significantly influenced by types of maternal plant manipulation and larval feeding, but not by the phylogeny of the host plant or weevil, which has diverse feeding niches even within closely related species, through maternal plant manipulation for immature weevils (e.g., shoot/petiole/seed borers, leaf miners, and leaf roll feeders). Weevil phylogenetic data indicate that although plant‐cutting behavior may have evolved as an adaptation to plant chemical defenses, some manipulation behaviors, such as cutting off plants with eggs or open and closed leaf roll construction, may be an innovative adaptation against parasitoids. However, we expect that an evolutionary arms race would exist between weevils with specific manipulations (e.g., constructing wrapped leaf rolls) and their specific parasitoids.

Contrasting Patterns of Host Adaptation in Two Egg Parasitoids of the Pine Processionary Moth (Lepidoptera: Thaumetopoeidae).

Adaptation of parasitoids to their phytophagous host is often mediated by environmental conditions and by the food plant of the phytophagous host. Therefore, the host food plant can indirectly affect the survival and fitness of parasitoids that also attack quiescent host stages, such as eggs, in which the resources available to the immature parasitoid stages are limited. Our aim was to investigate how two egg parasitoid species of the pine processionary moth, Thaumetopoea pityocampa (Denis & Schiffermüller), respond to variations in egg traits at the extremes of a west-to-east geographic gradient in northern Italy. We considered one specialist [Baryscapus servadeii (Domenichini)] and one generalist [Ooencyrtus pityocampae (Mercet)] parasitoid, which reproduce mainly by thelytokous parthenogenesis and are common throughout the whole range of this pest. The size and shell structure of the pine processionary moth eggs were studied under light microscopy and tested experimentally under controlled conditions. We can conclude that 1) the pine processionary moth egg shell thickness is inversely proportional to the parasitism performance; 2) the larger eggs from the pine processionary moth eastern population produce parasitoid females of a larger size, which have greater realized fecundity; 3) the generalist parasitoid performs successfully with either the "home" or "away" (i.e., from both extremes of the geographic gradient) pine processionary moth eggs, which is not the case for the specialist parasitoid. The implications of these responses in the regulation of phytophagous populations are numerous and should be considered in population dynamics studies and pest management programs.

Scale-dependent, contrasting effects of habitat fragmentation on host-natural enemy trophic interactions

Habitat fragmentation can have contrasting effects on species and their interactions within communities, changing community structure and function. Parasitoids and pathogens are key natural enemies in invertebrate communities, but their responses to fragmentation have not been explored within the same community. This study aimed to explore the scale-dependent effects of habitat fragmentation on the population density of a lepidopteran host and particularly its trophic interactions with a specialist parasitoid and virus. Host density and host larval-mortality from the parasitoid and the virus were measured in twelve isolated sites and thirteen connected sites. An index of habitat isolation was created based on the amount of suitable habitat surrounding sites at a range of spatial scales (0.1–5 km radii), and the direct and indirect effects of habitat isolation were analysed using generalised linear mixed effects models. Consistent with predictions, habitat isolation had direct negative effects on host density at the smallest and largest spatial scales, and indirect negative effects on host mortality from the virus at the largest scale, but in contrast to predictions it had direct positive effects on parasitism at small and medium scales. Higher trophic level species may still display responses to habitat fragmentation contrary to predictions based on well supported theory and empirical evidence. The mechanisms underlying these responses may be elucidated by studying responses, contrary to expectations, shared by related species. Developing general predictions about the responses of host-pathogen interactions to fragmentation will require greater understanding of the system-specific mechanisms by which fragmentation can influence pathogen transmission.

How to escape from the host nest: Imperfect chemical mimicry in eucharitid parasitoids and exploitation of the ants’ hygienic behavior

Communication in ants is based to a great extent on chemical compounds. Recognition of intruders is primarily based on cuticular hydrocarbon (CHC) profile matching but is prone to being cheated. Eucharitid wasps are specific parasitoids of the brood of ants; the immature stages are either well integrated within the colony or are protected within the host cocoons, whereas adult wasps at emergence must leave their host nest to reproduce and need to circumvent the ant recognition system to escape unscathed. The behavioral interactions between eucharitid wasps and workers of their host, the Neotropical ant Ectatomma tuberculatum, are characterized. In experimental bioassays, newly emerged parasitoids were not violently aggressed. They remained still and were grabbed by ants upon contact and transported outside the nest; host workers were even observed struggling to reject them. Parasitoids were removed from the nest within five minutes, and most were unharmed, although two wasps (out of 30) were killed during the interaction with the ants. We analyzed the CHCs of the ant and its two parasitoids, Dilocantha lachaudii and Isomerala coronata, and found that although wasps shared all of their compounds with the ants, each wasp species had typical blends and hydrocarbon abundance was also species specific. Furthermore, the wasps had relatively few CHCs compared to E. tuberculatum (22–44% of the host components), and these were present in low amounts. Wasps, only partially mimicking the host CHC profile, were immediately recognized as alien and actively removed from the nest by the ants. Hexane-washed wasps were also transported to the refuse piles, but only after being thoroughly inspected and after most of the workers had initially ignored them. Being recognized as intruder may be to the parasitoids’ advantage, allowing them to quickly leave the natal nest, and therefore enhancing the fitness of these very short lived parasitoids. We suggest that eucharitids take advantage of the hygienic behavior of ants to quickly escape from their host nests.

Habitat eradication and cropland intensification may reduce parasitoid diversity and natural pest control services in annual crop fields

Abstract California’s central coast differs from many agricultural areas in the U.S., which feature large tracts of monoculture production fields and relatively simple landscapes. Known as the nations salad bowl, and producing up to 90% of U.S. production of lettuces, broccoli and Brussels sprouts, this region is a mosaic of fresh vegetable fields, coastal meadow, chaparral shrubs, riparian and woodland habitat. We tested for relationships between the percent cover of crops, riparian and other natural landscape vegetation and the species richness of parasitic wasps and flies foraging in crops, such as broccoli, kale and cauliflower, and interpreted our results with respect to the decrease in natural habitat and increase in cropland cover prompted by a local microbial contamination event in 2006. Our key results are that: (1) as cropland cover in the landscape increased, fewer species of parasitoids were captured in the crop field, (2) parasitoid richness overall was positively associated with the amount of riparian and other natural vegetation in the surrounding 500m, (3) different groups of parasitoids were associated with unique types of natural vegetation, and (4) parasitism rates of sentinel cabbage aphid and cabbage looper pests were correlated with landscape vegetation features according to which parasitoids caused the mortality. Although individual species of parasitoids may thrive in landscapes that are predominantly short season crops, the robust associations found in this study across specialist and generalist parasitoids and different taxa (tachinid flies, ichneumon wasps, braconid wasps) shows that recent food safety practices targeting removal of natural vegetation around vegetable fields in an attempt to eliminate wildlife may harm natural enemy communities and reduce ecosystem services. We argue that enhancing biological diversity is a key goal for transforming agroecosystems for future productivity, sustainability and public health.

My Enemy's Enemies: Recruiting Hemipteran-Tending Generalist ants for Biological Control in Citrus Orchards by Spatial Partitioning of Foraging Webs

Generalist predators are contentious biocontrol agents, especially ants that protect pestilent hemipterans from specialist predators and parasitoids. We attempted to force generalist, hemipteran-tending ants into a degree of dietary specificity by spatially partitioning and simplifying their trophic web. Pupae of Helicoverpa armigera, Thaumatotibia leucotreta and Ceratitis capitata introduced into a citrus orchard survived significantly better in plots where all nests of two pestilent, generalist ant species namely Anoplolepis custodiens and Pheidole megacephala had been poisoned compared with untreated control plots. In some plots the ants' foraging environments were partitioned into arboreal and epigaeic trophic webs using sticky barriers to prevent ground-nesting ants from ascending the trees. Plots partitioned this way showed suppressed levels of survival of emplaced pest pupae that were similar to those in unpartitioned control plots. Pest survival was significantly lower for T. leucotreta than for H. armigera and C. capitata, implicating prey body size or life cycle duration as factors in predation by ants. Pheidole megacephala and the predator complex as a whole can be valuable agents in the natural control of soil-pupating citrus pests if they are restricted to the ground. Trunk banding, rather than poisoning, is therefore recommended as part of managing ecologically mercenary ants in citrus orchards.

Description of the Larval Instars ofLixadmontia franki(Diptera: Tachinidae)

We describe the larval stages of Lixadmontia franki Wood & Cave (Diptera: Tachinidae). The fly is a specialist parasitoid of bromeliad-eating weevils and a potential biological control agent for controlling an invasive bromeliad-eating weevil, Metamasius callizona (Chevrolat) (Coleoptera: Curculionidae), in Florida. Morphological characteristics that can be used to distinguish the instars of L. franki, including the mouth hook and cephalopharyngeal skeleton, body size and color, spinulae patterns, and presence and structure of spiracles, are described, measured, and illustrated. Fly larvae live in the host’s body cavity and attach their caudal end to the host’s tracheal tubes. The first instar builds a respiratory funnel and the second instar remains attached to the same point and builds upon the funnel. The third instar does not build upon the respiratory funnel. The third instar disconnects from the respiratory funnel shortly before exiting the host. First and second instars are metapneustic, but the third instar is amphipneustic.

Incomplete control of the diamondback moth, Plutella xylostella, by the parasitoid Cotesia vestalis in a cabbage field under tropical conditions

Immature Plutella xylostella (Lepidoptera: Plutellidae) and parasitoids were sampled for 39 months in an unsprayed cabbage field near Cotonou, Benin, to determine how and when host-parasitoid interactions influence the population dynamics of the moth in a tropical environment. Eighty-three samples were taken at approximately two-week intervals. There were no seasonal patterns in the abundance of immature moths, which was not correlated with weather variables, although heavy rainfall during the principal rainy season may have temporarily affected the population. The host-parasitoid system consisted almost exclusively of P. xylostella and its larval parasitoid Cotesia vestalis (Hymenoptera: Braconidae), both species occurring at similar levels of abundance (on average 7.5 ± 0.3 and 7.2 ± 0.3 individuals per plant, respectively). The tendency for host-parasitoid dynamics to cycle was apparent in the field. P. xylostella and C. vestalis showed coupled oscillations in abundance, with a time lag of about two weeks between host and parasitoid peaks. High parasitoid abundance resulted in significant decreases in moth abundance over several weeks. However, the parasitoid population in turn decreased, could not prevent the moth from rebounding, and there was no stable control of the pest. We conclude that under tropical conditions in which P. xylostella populations grow rapidly, combined with a high probability of recolonization from surrounding areas, biological control by a well-established specialist parasitoid reaches its limits and additional control measures are necessary.

Spatial ecology of host–parasitoid interactions: a threatened butterfly and its specialised parasitoid

Habitat conservation for threatened temperate insect species is often guided by one of two paradigms: a metapopulation approach focusing on patch area, isolation and number; or a habitat approach focusing on maintaining high quality habitat for the focal species. Recent research has identified the additive and interacting importance of both approaches for maintaining populations of threatened butterflies. For specialised host-parasitoid interactions, understanding the consequences of habitat characteristics for the interacting species is important, because (1) specialised parasitoids are particularly vulnerable to the consequences of fragmentation, and (2) altered interaction frequencies resulting from changes to habitat management or the spatial configuration of habitat are likely to have consequences for host dynamics. The spatial ecology of Cotesia bignellii, a specialist parasitoid of the threatened butterfly Euphydryas aurinia, was investigated at two spatial scales: within habitat patches (at the scale of individual aggregations of larvae, or ‘webs’) and among habitat patches (the scale of local populations). Parasitism rates were investigated in relation to larval web size, vegetation sward height and host density. Within patches, the probability of a larval webs being parasitized increased significantly with increasing number of larvae in the web, and parasitism rates increased significantly with increasing web isolation. The proportion of webs parasitized was significantly and negatively correlated with cluster density. Among habitat patches the proportion of parasitized webs decreased as cluster density increased. Clusters with a high proportion of larval webs parasitized tended to have lower parasitism rates per larval web. These results support the call for relatively large and continuous habitat patches to maintain stable parasitoid and host populations. Conservation efforts directed towards maintenance of high host plant density could allow E. aurinia to reduce parasitism risk, while providing C. bignellii with sufficient larval webs to allow population persistence.

Caught between parasitoids and predators - survival of a specialist herbivore on leaves and flowers of mustard plants.

The survival of insect herbivores typically is constrained by food choice and predation risk. Here, we explored whether movement from leaves to flowers increases survival of herbivores that prefer to feed on floral tissues. Combining field and greenhouse experiments, we investigated whether flowering influences the behavior of Pieris brassicae butterflies and caterpillars and, consequently, herbivore survival in the field. In this context, we investigated also if flowers of Brassica nigra can provide caterpillars refuge from the specialist parasitoid Cotesia glomerata and from predatory social wasps. By moving to flowers, caterpillars escaped from the parasitoid. Flowers are nutritionally superior when compared with leaves, and caterpillars develop faster when feeding on flowers. However, late-stage caterpillars can be preyed upon intensively by social wasps, irrespective of whether they feed on leaves or flowers. We conclude that flower preference by P. brassicae is more likely driven by nutritional advantages and reduced parasitism on flowers, than by risks of being killed by generalist predators.

Plant pathogen-induced volatiles attract parasitoids to increase parasitism of an insect vector

Interactions between plant pathogens and arthropods have been predominantly studied through the prism of herbivorous arthropods. Currently, little is known about the effect of plant pathogens on the third trophic level. This question is particularly interesting in cases where pathogens manipulate host phenotype to increase vector attraction and presumably increase their own proliferation. Indeed, a predator or a parasitoid of a vector may take advantage of this manipulated phenotype to increase its foraging performance. We explored the case of a bacterial pathogen, Candidatus Liberibacter asiaticus (Las), which modifies the odors released by its host plant (citrus trees) to attract its vector, the psyllid Diaphorina citri. We found that the specialist parasitoid of D. citri, Tamarixia radiata, was attracted more toward Las-infected than uninfected plants. We demonstrated that this attractiveness was due to the release of methyl salicylate. Parasitization of D. citri nymphs on Las-infected plants was higher than on uninfected controls. Also, parasitization was higher on uninfected plants baited with methyl salicylate than on non-baited controls. This is the first report of a parasitoid ‘eavesdropping’ on a plant volatile induced by bacterial pathogen infection, which also increases effectiveness of host seeking behavior of its herbivorous vector.

Sensilla on antenna, ovipositor and leg of Eriborus applicitus (Hymenoptera: Ichneumonidae), a parasitoid wasp of Holcocerus insularis staudinger (Lepidoptera: Cossidae)

AbstractEriborus applititus Sheng & Sun (Hymenoptera: Ichneumonidae) is a specialist parasitoid of the small carpenter moth Holcocerus insularis Staudinger (Lepidoptera: Cossidae). Each year damages to trees caused by H. insularis lead to extensive economic and ecological losses. E. applititus is thus a promising candidate for use as a biocontrol agent against H. insularis. To investigate the means by which E. applititus locates and parasitizes H. insularis, we used scanning electron microscopy to determine the morphology and distribution of sensilla on antenna, ovipositor and leg of male and female E. applititus. Eight different sensilla types were found: sensilla chaetica, sensilla trichodea, sensilla placodea, sensilla basiconica, sensilla coeloconica, sensilla pit basiconica, sensilla campaniformia and Böhm's bristles. The sensilla types were differently distributed in the three organs. In addition, differences between sexes were found in the distribution of sensilla trichodea type 2, sensilla placodea and sensilla chaetica type 4. Putative functions of the sensilla are discussed based on the morphological and location data and on previous research. Chemosensitive sensilla are putatively involved in host detection, pheromone detection and host discrimination processes. Mechanoreceptive sensilla likely function as vibrational sensors and are thought to be critical for accurate ovipositor positioning.

Trade-offs between developmental parameters of two endoparasitoids developing in different instars of the same host species

Trade-offs amongst life history traits is a major theme in evolutionary biology. Parasitoid wasps are important biological control agents and make excellent organisms to examine trade-offs in fitness related traits such as size, development rate and survival. Here, we examined trait-related trade-offs in 2 solitary endoparasitoids developing in different stages (or instars) of the same caterpillar host, the cabbage moth Mamestra brassicae. Microplitis mediator is a small specialist parasitoid that attacks first (L1) to third (L3) instars of M. brassicae; Meteorus pulchricornis is a larger highly generalized parasitoid that attacks L1–L4 instars of the same host species. When developing in early host instars (e.g. L1–L2), both parasitoids differently traded-off size against development time. In M. mediator, adult body mass was smaller in wasps developing in L1 than in L2 and L3 hosts, whereas development time was unaffected by instar. By contrast, adult body mass in M. pulchricornis was smaller and development time longer when developing in L1 and L2 than in L3 and L4 instars. Periodic starvation of M. brassicae caterpillars parasitized by M. pulchricornis further reduced adult mass and extended development time of wasps in L2 (but not L4) hosts. Maximum egg load in M. pulchricornis (but not M. mediator) was correlated with adult female body size. Our results imply that rapid development time is more important than body size for fitness in both species, although in M. pulchricornis both development time and adult size are traded off in determining the optimal phenotype. Developing a better understanding of association-specific patterns of development in parasitoids can assist in the optimization of mass rearing of these insects for biological control.

Attraction of two larval parasitoids with varying degree of host specificity to single components and a binary mixture of host-related plant volatiles

As an indirect defense to herbivore attack, plants release many types of volatile organic compounds (VOCs), which guide parasitoids to their herbivore hosts. In the present study, VOCs were categorized as those released passively from undamaged plants and herbivore-induced plant volatiles (HIPVs). HIPVs were further categorized into: (1) volatiles released by fresh damage plants, and (2) volatiles released by old damage plants. We used as models, two parasitoids with different degree of host specificity, Microplitis croceipes (specialist) and Cotesia marginiventris (generalist), to address the evolutionary and mechanistic question of whether specialist and generalist parasitoids differ in their use of VOCs for host location. Both species are solitary larval endoparasitoids in the same family (Hymenoptera: Braconidae) and are important parasitoids of caterpillar pests of cotton. Based on the results of previous studies, α-pinene, (Z)-3-hexenol, and (Z)-3-hexenyl acetate were selected as representatives of the different types of VOCs in cotton. The attraction of both parasitoid species to synthetic components and a binary mixture of the above VOCs was tested in four-choice olfactometer bioassays. Female M. croceipes showed the greatest attraction to the HIPVs while female C. marginiventris could not discriminate among the three VOCs. Conspecific males showed similar responses with a few exceptions. When presented with the choices; α-pinene, (Z)-3-hexenol and a binary mixture (50:50v/v) of the two compounds, the specialist showed the greatest attraction to the mixture. However, the mixture did not elicit such an additive effect on the attraction of the generalist. Overall response latency (time taken to choose VOCs) indicated species and sexual (in the specialist) differences. Using a simple model, this study provides a fundamental insight into odor preferences and discriminatory ability of the test parasitoids. The ecological significance and practical implications of these results are discussed.

Neotropical species of Meteorus Haliday (Hymenoptera: Braconidae: Meteorinae) parasitizing Arctiinae (Lepidoptera: Noctuoidea: Erebidae).

Three new species of Meteorus parasitoids of Arctiinae are described: Meteorus anuae n. sp., M. juliae n. sp. and M. mirandae n. sp. The first biological record for M. cecavorum Aguirre & Shaw as well as its cocoon description is reported. A comprehensive key for the Neotropical Meteorus attacking Arctiinae is provided. A total of nine Meteorus species have been reared from Arctiinae in the Neotropical Region. Six of them are gregarious and three solitary. The biological information about host and food plants concurs with the hypothesis of specialist parasitoids preferring "nasty" caterpillars.

Piper kelleyi, a hotspot of ecological interactions and a new species from Ecuador and Peru

We describe Piper kelleyi sp. nov., a new species from the eastern Andes of Ecuador and Peru, named in honor of Dr. Walter Almond Kelley. Piper kelleyi is a member of the Macrostachys clade of the genus Piper and supports a rich community of generalist and specialist herbivores, their predators and parasitoids, as well as commensalistic earwigs, and mutualistic ants. This new species was recognized as part of an ecological study of phytochemically mediated relationships between plants, herbivores, predators, and parasitoids. Compared to over 100 other Piper species surveyed, Piper kelleyi supports the largest community of specialist herbivores and parasitoids observed to date.

Natural Enemies of <I>Atta vollenweideri</I> (Hymenoptera: Formicidae) Leaf-Cutter Ants Negatively Affected by Synthetic Pesticides, Chlorpyrifos and Fipronil

In southern South America, Ada vollenweideri Forel (Hymenoptera: Formicidae) is a significant pest of several crops and forestry, also considered to reduce the carrying capacity of pastures. The most usual control method used in Latin America is the application of synthetic pesticides, mainly chlorpyrifos and fipronil. However, no studies have assessed the effects of these agrochemicals on natural enemies of ants. We aimed to evaluate the efficiency of these pesticides on leaf-cutter ants' control and to test their effect on phorid fly parasitoids. Chlorpyrifos failed to exert complete control over ant colonies in the field and was gravely detrimental to specific parasitoids, reducing their percentage of parasitism, pupal survivorship, and adult longevity. Fipronil, however, exerted complete control over the treated colonies. Laboratory tests using both pesticides, either on ants from foraging trails or on pupariae, showed that chlorpyrifos and fipronil decreased larval and pupal survivorship, as well as adult longevity of parasitoids, in comparison to controls. In conclusion, these pesticides will likely affect parasitoids with regard to their reproductive capacity, leading to the decreased levels of natural parasitism observed in the field after treatments. We discuss why neither pesticide should be taken into account for integrated pest management programs.

Consequences of asymmetric competition between resident and invasive defoliators: A novel empirically based modelling approach

Invasive species can have profound effects on a resident community via indirect interactions among community members. While long periodic cycles in population dynamics can make the experimental observation of the indirect effects difficult, modelling the possible effects on an evolutionary time scale may provide the much needed information on the potential threats of the invasive species on the ecosystem. Using empirical data from a recent invasion in northernmost Fennoscandia, we applied adaptive dynamics theory and modelled the long term consequences of the invasion by the winter moth into the resident community. Specifically, we investigated the outcome of the observed short-term asymmetric preferences of generalist predators and specialist parasitoids on the long term population dynamics of the invasive winter moth and resident autumnal moth sharing these natural enemies. Our results indicate that coexistence after the invasion is possible. However, the outcome of the indirect interaction on the population dynamics of the moth species was variable and the dynamics might not be persistent on an evolutionary time scale. In addition, the indirect interactions between the two moth species via shared natural enemies were able to cause asynchrony in the population cycles corresponding to field observations from previous sympatric outbreak areas. Therefore, the invasion may cause drastic changes in the resident community, for example by prolonging outbreak periods of birch-feeding moths, increasing the average population densities of the moths or, alternatively, leading to extinction of the resident moth species or to equilibrium densities of the two, formerly cyclic, herbivores.

Description of a new species of Anagyrus Howard (Hymenoptera: Chalcidoidea: Encyrtidae), a promising biological control agent of the invasive Madeira mealybug, Phenacoccus madeirensis Green (Hemiptera: Sternorrhyncha: Pseudococcidae).

Anagyrus amnestos sp. n. (Hymenoptera: Encyrtidae), a promising parasitoid of the invasive Madeira mealybug, Phenacoccus madeirensis Green (Hemiptera: Pseudococcidae), is described based on material collected from India. This parasitoid was identified as Anagyrus sp. nov. nr. sinope Noyes & Menezes in recent literature, and was initially collected in Georgia, USA. It was found to be a specific parasitoid of the Madeira mealybug and its biological attributes and potential as a biological control agent of this pest were studied. In what appears to be a case of fortuitous introduction, we detected this parasitoid in large numbers on Madeira mealybugs from the southern Indian state of Karnataka, where the mealybug is a recently introduced invasive pest. In view of its economic importance as a potential biological control agent of the Madeira mealybug, it is formally described and illustrated here. Comparative accounts of the new species vis-a-vis its close relatives in India and the Americas are provided.