Diversity and host associations of parasitoids attacking mycophagous drosophilids (Diptera: Drosophilidae) in northern and central Japan

The diversity and host associations of parasitoids attacking mycophagous drosophilids were studied in Tokyo (a warm‐temperate region) and Sapporo (a cool‐temperate region) in Japan. Field collections were carried out using traps baited with mushrooms in May, June, September and October 2009 in Tokyo and in July and August 2010 in Sapporo. The major drosophilid species that emerged from mushroom baits was Drosophila bizonata in Tokyo and D. orientacea in Sapporo. In total, 13 parasitoid species emerged from drosophilids occurring in mushroom baits, and 11 of them were larval parasitoids belonging to Braconidae and Figitidae. Among the 11 larval parasitoids, 10 were collected in Tokyo, while only two were collected in Sapporo. It is not known why their diversity differed so much between these two regions. Four of the 11 larval parasitoids have also been recorded from drosophilid larvae occurring in fruit (banana). The use of these two habitats (mushrooms and fruit) by these four species seems to reflect the occurrence (i.e. resource use) of their suitable hosts. On the other hand, most larval parasitoids from Tokyo attacked D. bizonata, and two larval parasitoids from Sapporo attacked D. orientacea, suggesting that the abundance of potential hosts is one of the important factors affecting their host use.     

Genetic differentiation of <Emphasis Type="Italic">Ganaspis brasiliensis</Emphasis> (Hymenoptera: Figitidae) from East and Southeast Asia

Ganaspis brasiliensis (Ihering) (Hymenoptera: Figitidae: Eucoilinae) is a Drosophila parasitoid that has often been misidentified as G. xanthopoda (Ashmead) in recent studies. This study aims to clarify genetic differentiation of G. brasiliensis based on the nucleotide sequences of the mitochondrial cytochrome oxidase subunit 1 (CO1) gene and three nuclear DNA regions, the inter-transcribed spacers 1 and 2 (ITS1 and ITS2) and putative 60S ribosomal protein L37 (RpL37), as well as crossing experiments. Four lineages are recognized in individuals assigned as G. basiliensis by morphology, (1) individuals occurring in Japan and probably South Korea, (2) individuals from a small subtropical island of Japan, Iriomote-jima, (3) individuals from temperate lowlands of Japan and high altitude areas of Southeast Asia, and (4) individuals occurring widely in Asia, America, Hawaii and Africa. The first lineage is a specialist of Drosophila suzukii (Matsumura), a pest of fresh fruit, and also the fourth lineage has a capacity to parasitize this pest species. The first, third and fourth lineages occur sympatrically at least in Tokyo. The third and fourth lineages differed in mate choice and host use to some extent, but post-mating isolation between them was almost absent.     

Native primary parasitoids and hyperparasitoids attacking an invasive aphid Uroleucon nigrotuberculatum in Japan

Since the invasion of Uroleucon nigrotuberculatum from North America we searched for parasitoids of this aphid on Solidago altissima in Japan to determine what species of native parasitoids attack the newly invasive aphid. We found three primary parasitoid species: Ephedrus plagiator and Praon yomenae (Braconidae, Aphidiinae) and Aphelinus albipodus (Aphelinidae). We also found eight hyperparasitoid species: Syrphophagus sp. (Encyrtidae), Dendrocerus carpenteri (Megaspilidae), Asaphes suspensus (Pteromalidae) and Pachyneuron aphidis (Pteromalidae) through both E. plagiator and A. albipodus; Phaenoglyphis villosa (Figitidae, Charipinae), Aprostocetus sp. (Eulophidae, Tetrastichinae) and D. laticeps through E. plagiator, and Alloxysta sp. nr brevis (Figitidae, Charipinae) through A. albipodus. Uroleucon nigrotuberculatum is usually attacked by rather polyphagous primary parasitoids, E. plagiator and A. albipodus, in Japan, where an oligophagous parasitoid specialized to allied aphid species is probably absent. The hyperparasitoid community of U. nigrotuberculatum is common to those of the aphids occurring in open field‐type habitats in Japan.     

Development of Asian parasitoids in larvae Of Drosophila Suzukii feeding on blueberry and artificial diet

In just a few years, the Asian fly Drosophila suzukii has invaded several continents and has become a very serious pest of many fruit crops worldwide. Current control methods rely on chemical insecticides or expensive and labour‐intensive cultural practices. Classical biological control through the introduction of Asian parasitoids that have co‐evolved with the pest may provide a sustainable solution on condition that they are sufficiently specific to avoid non‐target effects on local biodiversity. Here, we present the first study on the development of three larval parasitoids from China and Japan, the Braconidae Asobara japonica and the Figitidae Leptopilina japonica and Ganaspis sp., on D. suzukii. The Asian parasitoids were compared with Leptopilina heterotoma, a common parasitoid of several Drosophilidae worldwide. The three Asian species were successfully reared on D. suzukii larvae in both, blueberry and artificial diet, in contrast to L. heterotoma whose eggs and larvae were encapsulated by the host larvae. All parasitoids were able to oviposit one day after emergence. Asobara japonica laid as many eggs in larvae feeding in blueberry as in artificial diet, whereas L. heterotoma oviposited more in larvae on the artificial diet and the Asian Figitidae oviposited more in larvae feeding on blueberry. Ganaspis sp. laid very few eggs in larvae in the artificial diet, suggesting that it may be specialized in Drosophila species living in fresh fruits. These data will be used for the development of a host range testing to assess the suitability of Asian parasitoids as biological control agents in invaded regions.     

Bioinformatic analysis suggests potential mechanisms underlying parasitoid venom evolution and function

Hymenopteran parasitoid wasps are a diverse collection of species that infect arthropod hosts and use factors found in their venoms to manipulate host immune responses, physiology, and behaviour. Whole parasitoid venoms have been profiled using proteomic approaches, and here we present a bioinformatic characterization of the venom protein content from Ganaspis sp. 1, a parasitoid that infects flies of the genus Drosophila. We find evidence that diverse evolutionary processes including multifunctionalization, co-option, gene duplication, and horizontal gene transfer may be acting in concert to drive venom gene evolution in Ganaspis sp.1. One major role of parasitoid wasp venom is host immune evasion. We previously demonstrated that Ganaspis sp. 1 venom inhibits immune cell activation in infected Drosophila melanogaster hosts, and our current analysis has uncovered additional predicted virulence functions. Overall, this analysis represents an important step towards understanding the composition and activity of parasitoid wasp venoms.     

Resistance of Drosophila suzukii to the larval parasitoids Leptopilina heterotoma and Asobara japonica is related to haemocyte load

Unlike other Drosophila species, the invasive Drosophila suzukii Matsumura (Diptera: Drosophilidae) shows a remarkable pest status. Among the physiological traits that may explain the high level of resistance to parasitoids of Drosophila larvae, the haemocyte load is shown repeatedly to play an important role. To determine whether haemocyte load can explain immunity resistance of D. suzukii to parasitoids, the haemocytes of parasitized and healthy larvae are quantified in two Japanese and three French populations of D. suzukii. Parasitization tests are conducted with two larval parasitoids: the paleartic Leptopilina heterotoma Thomson (Hymenoptera: Figitidae) and the Asian Asobara japonica Belokobylskij (Hymenoptera: Braconidae). Based on morphological and functional criteria, D. suzukii has classes of haemocytes similar to those described in Drosophila melanogaster. However, healthy larvae of the five populations tested possess particularly large numbers of haemocytes compared with D. melanogaster. Haemocyte load is also higher in larvae from the French populations than in the Japanese strains. The ability of D. suzukii larvae to encapsulate eggs of L. heterotoma is associated with a particularly high load of circulating haemocytes. However, it is notable that A. japonica induces a strong depression of the haemocyte population in this resistant host associated with an inability to encapsulate parasitoid eggs. The results show that the cellular immune system plays a major role in the failure of larval parasitoids to develop in most instances in larvae of D. suzukii, possibly contributing to the success of this species as an invader.     

Toxicity of venom of Asobara and Leptopilina species to Drosophila species

The Drosophila parasitoid Asobara japonica Belokobylskij (Hymenoptera: Braconidae) has highly toxic venom that kills host larvae if its injection is not followed by an injection of lateral oviduct components along with egg‐laying. In the present study, the venoms of seven other Drosophila parasitoids (Asobara rossica, Asobara rufescens, Asobara pleuralis, Leptopilina heterotoma, Leptopilina japonica, Leptopilina ryukyuensis, and Leptopilina victoriae) are tested against three kinds of Drosophila species (i.e. Drosophila species that are suitable as host for focal parasitoids, those that are resistant to the parasitoids, and a cosmopolitan species, Drosophila simulans). Venoms of the three Asobara species are not toxic to any of Drosophila species, whereas those of the four Leptopilina species are toxic to some Drosophila species. The toxicity of venom varies among Leptopilina species, and the susceptibility to venom also varies among host Drosophila species. Furthermore, toxicity and paralytic effects of venom are not correlated. Because the toxicity of venom is not adaptive for parasitoids, it may be an inevitable side effect of some components that play an essential role in parasitism.     

Mutualistic ants and parasitoid communities associated with a facultative myrmecophilous lycaenid,Arhopala japonica,and the effects of ant attendance on the avoidance of parasitism

Herbivorous insects have evolved various defensive strategies to avoid their primary enemies, parasitoids. Many species of Lycaenidae (Lepidoptera) have food‐for‐protection mutualism with ants in their larval stages, where larvae produce nectar for ants and in return ants exclude parasitoids as well as predators. Myrmecophilous relationships are divided into two categories, obligate and facultative, by degrees of myrmecophily. Although parasitoids attacking obligate lycaenids always encounter lycaenid‐specific ant species, parasitoids that use facultative lycaenids are likely to encounter diverse ant species showing various defense systems. However, we know little about the parasitoid community of facultative lycaenid larvae. In this study, we investigated the mutualistic ant and parasitoid communities of a facultative myrmecophilous species, Arhopala japonica, in seven localities in Japan. The present field observation newly recorded four ant species attending A. japonica larvae, and combined with the previous data, the number of attending ant species reached 16, which is nearly the maximum number of reported attending ant species among myrmecophilous lycaenids. However, the present study revealed that almost all parasitized A. japonica larvae were attacked by a single braconid species, Cotesia sp. near inducta. We also assessed the efficiency of facultative ant defense against the parasitoid in the laboratory and revealed that oviposition by Cotesia sp. near inducta females was almost completely hindered when A. japonica larvae were attended by ants. This suggests that the dominant parasitoid does not have effective traits to overcome defensive behavior of ants and that the female wasps oviposit mainly in A. japonica larvae without intensive attendance.     

Are island and mainland biotas different? Richness and level of generalism in parasitoids of a microlepidopteran in Macaronesia

Island communities are exposed to several evolutionary and ecological processes that lead to changes in their diversity and structure compared to mainland biotas. These phenomena have been observed for various taxa but not for parasitoids, a key group in terms of community diversity and functioning. Here we use the parasitoid communities associated with the moth Acroclita subsequana (Lepidoptera: Tortricidae) in the Macaronesian region, to test whether species richness differs between islands and mainland, and whether island parasitoid faunas are biased towards generalist species. Host larvae were collected on several islands and adjacent mainland, carefully searched for ectoparasitoid larvae and dissected to recover any endoparasitoids. Parasitoids were classified as idiobionts, which usually have a wide host range (i.e. generalists), or koinobionts that are considered specialists. Mainland species richness was lower than expected by chance, with most of the species being koinobionts. On the other hand, island communities showed a greater proportion of idiobiont species. Overall parasitism rates were similar between islands and mainland, but islands had higher rates of parasitism by idiobionts than expected by chance, and mainland areas showed the highest koinobiont parasitism rates. These results suggest that island parasitoid communities are dominated by generalists, in comparison to mainland communities. Several hypotheses may explain this pattern: (1) generalist parasitoids might have better dispersal abilities; (2) they may be less constrained by ‘sequential dependencies’; and (3) island parasitoids probably have fewer competitors and/or predators, thus favouring the establishment of generalists. New studies including multiple hosts, other habitats, and/or more islands are necessary to identify which of these processes shape island parasitoid communities.     

Structure of a herbivore–parasitoid community: Are parasitoids shared by different herbivore guilds?

Plant–herbivore–parasitoid interactions are a common occurrence in terrestrial food webs. Few parasitoids are thought to be shared by host insects of different feeding guilds because different parasitism strategies are required to use hosts of different feeding types. However, this assumption has rarely been tested using data from nature. To clarify whether parasitoids are shared among host guilds, I examined the structure of parasitoid communities on herbivore guilds associated with two Rhododendron species (Ericaceae) in a temperate secondary forest in central Japan. Leaf- and flower-feeding insects were collected from Rhododendron reticulatum and Rhododendron macrosepalum shrubs and reared in the laboratory for 3 years from April 1999 to March 2002. In total, 79 species of holometabolous herbivores (Lepidoptera, Diptera, Coleoptera, and Hymenoptera) were recorded, with 62 species on R. reticulatum and 51 species on R. macrosepalum. A total of 81 parasitoid species (Hymenoptera and Diptera) was recorded from the sampled herbivores, with 48 species from those on R. reticulatum and 50 species from those on R. macrosepalum. In total, 36 herbivore species were parasitised by 1–18 parasitoid species per host species, although the number of parasitoid species was strongly affected by sample size. Parasitoids that had two or more host species frequently attacked herbivore species from different families or on different host plants, whereas they did not attack species from different herbivore guilds; no parasitoids were shared between external feeders and rollers. Therefore, my results support the hypothesis that few parasitoids are shared among herbivores of different feeding guilds.     

Distribution and reproduction of the temperate-specific morphotype of the coral Favites flexuosa in the subtropical region,Lyudao, Taiwan

Favites flexuosa is one of the abundant coral species in the temperate regions of Japan. Although the species ranges widely, from tropical to temperate regions of the Indo-Pacific, colonies of this species living in temperate areas exhibit specific morphological features (in terms of color and skeletal attributes). In addition, the temperate-specific morphotype is limited in distribution to the temperate regions of Japan and has not been recorded in subtropical Okinawa. In the present study, we recorded the temperate morphotype in subtropical Lyudao (Green Island), Taiwan, suggesting that the morphotype is more widely distributed than previously thought and may have colonized temperate Japan directly from Lyudao. We describe the first records of spawning at Lyudao, Taiwan, and also at Wakayama in temperate Japan. In laboratories located in either region, spawning was observed between 30?min and 1?h after sunset. Intraspecific crossing of morphotype samples from either region revealed that the fertilization rates were high (>90%). In addition, we crossed F. flexuosa with Diploastrea favus at Lyudao. The two species hybridized successfully although the fertilization rate was relatively low.     

Geographic variation in host-selection behaviour in the Drosophila parasitoid Leptopilina clavipes

In parasitoid wasps, the process of locating and selecting suitable oviposition sites is under strong selection due to the direct linkage of successful host selection and female fitness. Leptopilina clavipes Hartig (Hymenoptera: Figitidae) is a parasitoid wasp of larvae of several Drosophila species that occurs over Western Europe, where it shows genetic differentiation between populations from northern and southern Europe. It is expected to experience differential selection pressures on both physiological (survival) and behavioural (host selection) components of foraging, because it occurs over a broad geographic range. We investigated whether the genetic differentiation in L. clavipes is linked to differentiation in both the physiological and behavioural components of foraging. We compared survival and host‐selection behaviour of two L. clavipes strains, one originating from northwestern Europe and one from southern Europe. In a series of choice experiments, females were offered pairs of larvae from three host species that are present in both regions, but use different breeding substrates: Drosophila phalerata Meigen (fungi), Drosophila subobscura Collin (rotting plant material, fungi, and fermenting fruits), and Drosophila melanogaster Meigen (fermenting fruits) (all Diptera: Drosophilidae). Survival patterns across the three host species were similar for both L. clavipes strains. Host‐selection behaviour did differ, where parasitoids from southern Europe accepted all hosts offered, while parasitoids from northwestern Europe were more specialists and accepted hosts breeding in fungi, but were reluctant towards D. melanogaster. This differentiation in host‐selection behaviour reflects the genetic differentiation present in European L. clavipes and shows adaptation to local differences in host communities.     

Temperature dependence of development rate and adult size in Drosophila species: biophysical parameters

Adult size in Drosophila results from the ratio of the rate of biomass increase and the rate of differentiation, both rates being temperature sensitive. Data on rates and size are collected in two tropical and two temperate Drosophila species; differentiation rate is higher in the two tropical species, growth rate differs between the large and small species of similar climatic origin. A biophysical model is used to evaluate the temperature dependence of adult size in Drosophila. The model is based upon the Sharpe–Schoolfield equation connecting enzyme kinetics and biological rates. Temperature sensitivities of growth rate, development time, and wing and thorax size are characterized by biophysical parameters. The biophysical parameter indicating trait specific temperature sensitivity is lower in tropical species than in temperate species, both for growth rate and for differentiation rate. In the larger species of a climate pair, thorax size and wing size prove to differ in pattern of temperature dependence; in the smaller species of a geographical pair, thorax size and wing size have identical patterns of temperature dependence.     

Structure and dynamics of the parasitoid community shared by two herbivore species on different host plants

The structure of the parasitoid community on phytophagous insects can be affected by host plant properties, such as chemical compounds, trichomes, and glandular hairs. To clarify effects of host plants on herbivores and the parasitoid community, I examined the structure and dynamics of the parasitoid community associated with two species of Caloptilia moths (Lepidoptera: Gracillariidae) that feed on different Rhododendron species (Ericaceae) for 3 years in a temperate secondary forest in central Japan. Caloptilia azaleella had overlapping generations in summer and overwintered as larvae on leaves of R. macrosepalum. Caloptilia leucothoes also had overlapping generations in summer, but it did not overwinter on the deciduous shrub R. reticulatum. The parasitoid community of C. azaleella larvae and pupae was composed of 18 species, whereas that of C. leucothoes was composed of seven species. Five species of parasitoids attacked both Caloptilia species. The most abundant parasitoid, Apanteles cf. xanthostigma (Hymenoptera: Braconidae), more frequently attacked C. azaleella than C. leucothoes larvae. In contrast, another abundant parasitoid, Acrysocharoides sp. (Hymenoptera: Eulophidae), more frequently attacked C. leucothoes than C. azaleella larvae. This differential parasitism by the most abundant parasitoid species may be responsible for the differential structure and dynamics of the parasitoid community between the Caloptilia species. The host plant of C. azaleella, R. macrosepalum, more frequently trapped and killed parasitoids (of similar size to Acrysocharoides sp.) on the glandular hairs of leaves than did R. reticulatum. The differential effect of host plants on abundant parasitoids may be related to the differential parasitism by the two abundant parasitoids shared by the herbivore hosts.     

Biology of Doryctobracon brasiliensis at different temperatures: development of life table and determining thermal requirements

Doryctobracon brasiliensis (Szépligeti) is a parasitoid larval–pupal of fruit flies and has great potential to be used in biological control programmes as it feeds on other Anastrepha species in addition to Anastrepha fraterculus (Wiedemann). This study investigated the biology of D. brasiliensis at different temperatures to design a life fertility table and determine thermal requirements. The parasitoids were multiplied in larvae of A. fraterculus in air‐conditioned chambers at 15, 18, 20, 22, 25, 28 and 30°C, 70 ± 20% RH and photophase of 12 h. We determined the number of offspring, sex ratio, longevity of males and females and duration of egg–adult period. The temperature range 18–22°C ensures higher fecundity and at 20°C, and the average number of offspring per female was 152.77 parasitoids. The sex ratio of offspring produced was reduced with increasing temperatures. Longevity of males and females of D. brasiliensis was reduced by increasing temperatures. At 15, 28 and 30°C, there was no development of immature stages. For the temperature range 18–25°C, the duration of egg–adult period of D. brasiliensis was inversely proportional to temperature. At 20 and 22°C, we observed the highest values of net reproduction rate (Ro) and finite reason of increase (λ), meaning that at the estimated optimum temperature (21°C), the population of D. brasiliensis increased 47 times each generation. The lower temperature threshold for development was 10.01°C and the thermal constant (K) 303.21 degree/days. This information confirms that D. brasiliensis is better suited to temperate environments, which implies a significant potential for the use of D. brasiliensis in the control of A. fraterculus, because most areas occupied by this pest are in temperate regions. In addition, D. brasiliensis is useful in mass rearing systems in laboratory.     

Food web structure of aphids and their parasitoids in Belgian fruit agroecosystems

Community structures of aphids and their parasitoids were studied in fruit crop habitats of eastern Belgium in 2014 and 2015. Quantitative food webs of these insects were constructed separately for each year, and divided into subwebs on three host‐plant categories, fruit crop plants, non‐crop woody and shrub plants and non‐crop herbaceous plants. The webs were analyzed using the standard food web statistics designed for binary data. During the whole study period, 78 plant species were recorded as host plants of 71 aphid species, from which 48 parasitoid species emerged. The community structure, aphid / parasitoid species‐richness ratio and trophic link number varied between the two years, whereas the realized connectance between parasitoids and aphids was relatively constant. A new plant–aphid–parasitoid association for Europe was recorded. Dominant parasitoid species in the study sites were Ephedrus persicae, Binodoxys angelicae and Praon volucre: the first species was frequently observed on non‐crop trees and shrubs, but the other two on non‐crop herbaceous plants. The potential influence, through indirect interactions, of parasitoids on aphid communities was assessed with quantitative parasitoid‐overlap diagrams. Symmetrical links were uncommon, and abundant aphid species seemed to have large indirect effects on less abundant species. These results show that trophic indirect interactions through parasitoids may govern aphid populations in fruit crop habitats with various non‐crop plants, implying the importance for landscape management and biological control of aphid pests in fruit agroecosystems.     

Resource Partitioning among Parasitoids (Hymenoptera: Braconidae) of Phoracantha semipunctata in Their Native Range

The Eucalyptus longhorned borer, Phoracantha semipunctata (F.), is native to Australia, but it has been introduced without its natural enemies into many parts of the world in which its Eucalyptus spp. host has been planted. The beetle has developed large populations in these novel habitats and has been responsible for the mortality of large numbers of trees. Although there is a considerable catalogue of the parasitoids of the beetle in Australia, limited ecological information on the assemblage of parasitoids attacking P. semipunctata is available. We removed bark from 40 felled trees, recorded gallery width and bark thickness over parasitized larvae, and removed all parasitoids. Adult size, sex, and species were recorded when the parasitoid pupae eclosed. Syngaster lepidus Brullè, Jarra phoracantha Austin, Quicke, and Marsh, J. maculipennis Austin, Quicke, and Marsh, and J. painei Austin and Dangerfield were most commonly collected. The solitary parasitoid S. lepidus preferred smaller larvae than did the gregarious Jarra spp. The two species with shorter ovipositors, J. maculipennis and J. painei, parasitized larvae under thinner bark than did the other two species with longer ovipositors. There was a significant positive correlation between host larval size and number of parasitoid pupae of the gregarious species. Also, there was a significant positive correlation between host larval size and parasitoid adult size. The ecological relationships between this assemblage of parasitoids and their beetle host may be useful in establishing an effective biological control program.     

Alien herbivores and native parasitoids: rapid developments and structure of the parasitoid and inquiline complex in an invading gall wasp Andricus quercuscalicis (Hymenoptera: Cynipidae)

Abstract.

• 1 Rapid and substantial changes have occurred in the parasitoid and inquiline community associated with the agamic galls of Andricus quercuscalicis since it invaded Britain in the late 1950s. The number of parasitoid and inquiline species has risen from one to thirteen over a 15-year period. Although the number of species has been relatively consistent over the last 8 years, the species composition has changed considerably and in a highly characteristic way during this period.
• 2 The parasitoid complex can be divided into two broadly distinct sets of parasitoid species; one set attacks only the gall former whereas the other set concentrates on the inquilines living in the wall of the gall.
• 3 The most dramatic change, however, is in the abundance of inquilines which were reported to be virtually absent in earlier studies on this community in Britain. Over a period of only 5 years, between 1988 and 1993, inquiline attack rose from less than 0.01 to an average of 0.26 inquilines per gall. The intensity of inquiline attack is geographically heterogenous, with high inquiline numbers restricted to south-east England. Because of the relatively high specificity of the parasitoids, high inquiline abundance is positively correlated with parasitoid species richness in knopper galls.
• 4 Parasitism rates, particularly on the gall former, were generally low (<10%). Over the last 5 years, however, seven parasitoid species have been consistently recorded and the mortality caused by these species has increased continuously. The species composition of the community associated with this alien gall wasp in Britain has quickly converged to the community known from its native range in continental Europe. Parasitoid species known to attack the galls of A.quercuscalisis on the continent have been recorded from it in Britain for the first time mainly in areas where inquilines have recently become abundant.
• 5 Since rates of parasitism of the gall former are still low, parasitoids are unlikely to play a major role in the population dynamics of this invading gall wasp at present, but the rapidly increasing inquiline and parasitoid attack could be a source of increased mortality for native cynipid species which are the alternative hosts of those parasitoid species.

     

Distribution, host specificity, and overwintering of Celatoria bosqi Blanchard (Diptera: Tachinidae), a South American parasitoid of Diabrotica spp. (Coleoptera: Chrysomelidae: Galerucinae)

The genus Diabrotica (Coleoptera: Chrysomelidae) includes a great number of pest species, including some of the most important crops pests of the Americas. However, only five parasitoid species have been recorded for it. The parasitoid Celatoria bosqi Blanchard was the first parasitoid described from Diabrotica spp. in South America, where substantial parasitism has been observed. C. bosqi has been collected almost throughout the South American distribution of its main host, Diabrotica speciosa (Germar), in an area that includes temperate and tropical lowlands, and semiarid to humid highlands. Three Diabrotica species were found to host the parasitoid, D. speciosa (Germar), Hystiopsis sp., and Diabrotica viridula (F.), with a total parasitism of 2.60, 5.55, and <0.02%, respectively. Laboratory experiments with field beetles and puparia, reared in the laboratory, indicate that C. bosqi overwinters obligatorily in overwintering adult host beetles, remaining quiescent in its live host below developmental temperatures. Based on the known climatic range of C. bosqi, and its requirement of adult overwintering hosts, a potential distribution in North America is projected.