Impact of the arundo wasp,Tetramesa romana (Hymenoptera: Eurytomidae), on biomass of the invasive weed,Arundo donax (Poaceae: Arundinoideae), and on revegetation of riparian habitat along the Rio Grande in Texas

An invasive grass, Arundo donax, occupies thousands of hectares of arid riparian habitat along the Rio Grande in Texas and Mexico, and has negative impacts on national security, water resources, and riparian ecosystems. The shoot-tip-galling wasp Tetramesa romana was released in 2009 between Brownsville and Del Rio, Texas, and has dispersed over 800?km along the river channel. Plots along the river were surveyed for shoot counts of arundo and all other plant species in 2016 at seven sites in regions in which prior studies had documented a 22% decline in arundo biomass (estimated from live shoot length) from 2007 to 2014. Estimated live biomass declined a further 32% between 2014 and 2016. Native plants accounted for 86% of the 44 species encountered in plots. Individual plots averaged five plant species, and arundo was most abundant in only 9 of 21 plots. Arundo live biomass and shoot density were negatively associated with plant diversity, indicating that live arundo interferes with germination and/or survival of other plant species. The proportion of dead shoots in plots, proportion of wasp-galled shoots, and density of exit holes made by emerging adult wasps per metre live main shoot length were positively associated with plant diversity in a combined model. Regressions indicated that the effects of wasp damage measures on diversity were mediated through their effects on main shoot mortality. By reducing live arundo biomass, the arundo wasp is fostering recovery of native plant communities at riparian sites along the Rio Grande.     

Impact of the biological control agent Tetramesa romana (Hymenoptera: Eurytomidae) on Arundo donax (Poaceae: Arundinoideae) along the Rio Grande River in Texas

Five years post-release of the arundo gall wasp, Tetramesa romana, into the riparian habitats of the lower Rio Grande River, changes in the health of the invasive weed, Arundo donax, or giant reed, have been documented. These changes in plant attributes are fairly consistent along the study area of 558 river miles between Del Rio and Brownsville, TX, and support the hypothesis that the arundo wasp has had a significant impact as a biological control agent. Plant attributes were measured prior to release in 10 quadrats at each of 10 field sites in 2007, and measured again at the same undisturbed sites, 5 years after the release of T. romana, in 2014. Above ground biomass of A. donax decreased on average by 22% across the 10 sites. This decline in biomass was negatively correlated to increased total numbers of T. romana exit holes in main and lateral shoots per site in 2014 compared to 2007. Changes in biomass, live shoot density and shoot lengths, especially the positive effect of galling on main and lateral shoot mortality, appear to be leading to a consistent decline of A. donax. Economically, this reduction in A. donax biomass is estimated to be saving 4.4 million dollars per year in agricultural water. Additional impacts are expected as populations of the wasp increase and as other biological control agents such as the arundo scale, Rhizaspidiotus donacis, become more widespread.     

Interactions Between Shoot Age Structure, Nutrient Availability and Physiological Integration in the Giant Bamboo Phyllostachys pubescens

Abstract: The age structure of adult shoots, the nutrient availability of the habitat, and their interaction, are important factors influencing the productivity of bamboo groves. In a field fertilization experiment over two years we examined the impact of physiological integration on the emergence, growth, and survival of new shoots of Phyllostachys pubescens, a giant woody bamboo. Impacts of physiological integration were compared using uniform and patchy fertilization treatments. The number of new shoots emerging per plot significantly increased with the application of fertilizer (NPK), but the increase was constrained by the age structure of adult shoots. In a year with a high proportion of shoots with new (first-year) leaves many more new shoots emerged than in a year with a low proportion of new leaves. Mean survivorship of the new shoots was constant at 20 % for all treatments in both years of study. Surprisingly, fertilization did not increase DBH or height of the new shoots, suggesting that shoot size was fixed early in ontogeny. The pattern of fertilizer application, either uniform or patchy, did not affect the total number of new shoots produced. In the case of patchy application, more new shoots developed in unfertilized patches in comparison to uniformly unfertilized plots, probably because these parts of the clone received resources via the rhizomes from the adult shoots in adjacent fertilized patches. The production of new shoots in fertilized patches, in turn, was lower than that in uniformly fertilized plots as a result of this physiological integration. The results are discussed in the general context of the impact of integration on clonal plant performance in dense stands.     

Impact of two shoot-galling biological control candidates on Russian knapweed, Acroptilon repens

Russian knapweed, Acroptilon repens, is one of the most serious exotic invaders of temperate grasslands in North America. Here we present results from a field experiment in which we quantified the impact of two potential biological control agents, the gall wasp Aulacidea acroptilonica V.Bel. (Hymenoptera, Cynipidae) and the gall midge Jaapiella ivannikovi Fedotova (Diptera, Cecidomyiidae), on A. repens under field conditions in the plant’s native range in Uzbekistan. Attack by A. acroptilonica reduced shoot length by 21%, above-ground biomass by 25% and seed output by 75%, while attack by J. ivannikovi reduced shoot length by 12%, above-ground biomass by 24%, and seed output by 92%. The results of these field experiments are likely to accurately reflect the potential of these two gall formers to reduce above-ground biomass and sexual reproduction of A. repens shoots, since the shoots were part of a clonal network. Despite this, the attacked shoots were not able to compensate for the reallocation of plant resources to gall formation. Moreover, the mean number of galls per shoot obtained in the experiments was within the range of observed gall incidences in the native range. The impact of these two gall-forming insects on Russian knapweed in North America will depend on the population size the species reach and on the timing of attack. The highest impact is likely to occur when the insects attack shoots that have not yet started producing flower-buds.     

Effect of water deficit on generation time and reproduction of the gall wasp Tetramesa romana,a biological control agent of giant reed (Arundo donax)

Water deficit stress can reduce the reproductive performance of galling insects, but has not previously been studied in the context of mass-rearing of a galling agent on a perennial grass. The effects of water deficit were examined for the wasp Tetramesa romana Walker (Hymenoptera: Eurytomidae), released in the Lower Rio Grande Basin of Texas and Mexico in 2009 and in northern California in 2010 for control of giant reed (Arundo donax (L)) (Poaceae). In one study, water deficit was imposed for 7–10 weeks during gall maturation, ending when adult progeny began to emerge. Aboveground water content was reduced by 1.7% and culm height by 41% in pots receiving one-fourth of normal watering (soil saturation), indicating that water deficit stress occurred. Water deficit did not affect proportion of culms successfully galled or number of progeny produced. However, time to first exit hole appearance was 2–4 days longer and adult wasp generation time 5–7 days longer on galls on water deficit–stressed compared to control culms, thereby reducing the wasp's intrinsic rate of increase. Water deficit imposed only during parent wasp oviposition had no effect on galling success or reproduction. Water deficit thus has a negative effect on rearing by delaying adult emergence and reducing the rate of population increase, even without affecting adult fertility. Mass-rearing should involve well-watered plants, and variable drought conditions in the field should be considered when evaluating T. romana establishment and impact.     

Biology of Leipothrix dipsacivagus (Acari: Eriophyidae), a candidate for biological control of invasive teasels (Dipsacus spp.)

The present study describes key aspects of the biology of Leipothrix dipsacivagus, an eriophyid mite that is under study as a biological control candidate of Dipsacus fullonum and D. laciniatus (Dipsacaceae). Preliminary host-specificity tests have shown that it can develop and reproduce only on Dipsacus spp. (teasels). Studies were conducted in a laboratory at 26 ± 2^oC with 16 h of light per day. Mites for the stock colony were collected from D. laciniatus in Klokotnitsa, Bulgaria and reared on rosettes of D. laciniatus in the laboratory. Unfertilized L. dipsacivagus females reared in isolation from the juvenile stage produced male offspring only, while progeny of fertilized females were of both sexes, suggesting arrhenotokous parthenogenesis with haplodiploid sex determination. Experiments were designed to compare male progeny from fertilized females to males from unfertilized females and to compare males and females from fertilized females. Male progeny of virgin mothers had significantly longer durations of active immature stages and total egg-to-adult period than male progeny of fertilized females. Female progeny had significantly longer durations of egg incubation, active immature stages and egg-to-adult period than male progeny from fertilized mothers. Adult longevity was significantly greater in females than in males. Fertilized females produced significantly more eggs per day and overall than virgin females. The results of this study suggest that fertilization status of L. dipsacivagus females can affect both their own fecundity and the development of their male progeny.     

Sex allocation and effects of superparasitism on secondary sex ratios in the gregarious parasitoid, Trichogramma chilonis (Hymenoptera: Trichogrammatidae)

The role of sex-controlling behaviour at oviposition in generating primary sex ratios, and the effect of larval competition on secondary sex ratios, were studied in the gregarious endoparasitoid, Trichogramma chilonis. The production of a fertilized (female) egg is indicated by the incorporation of a pause in abdominal movements during oviposition, while the absence of it indicates the production of an unfertilized (male) egg. During each ovipositional bout, the first male egg is deposited at the second oviposition, and thereafter at intervals of about eight eggs. This simple pattern enables the wasps to adjust their progeny sex ratios under local male competition to a wide range of host size. Inexperienced wasps do not distinguish between parasitized and healthy hosts. Immature mortality is not significantly different between the sexes when a host is attacked by a single wasp, while females suffer higher immature mortality than males when superparasitism occurs.     

Alleviation of sodicity stress on rice genotypes by Phosphorus fertilization

Rice seedlings transplanted into sodic soil are exposed to an excess of potentially toxic ions as well as nutritional imbalance, both of which adversely affect their growth and yield. The present study was aimed to investigate the beneficial effects of fertilization with phosphorus and potassium on the plants at varying sodicity levels and also the response of genotypes with known variability in their tolerance to sodicity. In pot-house experiments during two seasons, the alleviating effects of P and K fertilization on three rice genotypes were examined at four sodicity levels. Seedlings of CSR13 and Jaya (both moderately tolerant to sodicity), died by 25–35 days after transplanting in sodic soils of pH 9.7–9.9 where Olsen's P was 12.5 and 14.8 kg/ha, respectively. However, there was no problem of survival or growth in these soils when Olsen's P was 17.6 and 20.8 kg/ha. Depletion in P from 12.0 kg to 10 kg resulted in some mortality of the seedlings even at pH 9.1. Sodicity tolerant genotype CSR10, did show some survival and growth even at pH 9.9 with Olsen's P at 14.8 kg/ha (without P fertilization) which suggests that differences in tolerance to sodicity which exist at genotypic level are not masked by low P. None of the three genotypes showed any survival problem at pH 8.0 and 8.1 with Olsen's P at 8.5 and 8.7 kg/ha, respectively. Seedlings in P fertilized sodic soils not only produced significantly more new roots but also higher root biomass than those in unfertilized sodic soils and these roots seem to have some control on Na uptake as reflected by low Na concentration in the shoots. Thus, P fertilization not only improved P and K status of plants but also reduced the concentration of potentially toxic Na ions in shoots, resulting in better survival, growth and yield. Although fertilization with K alone did improve shoot K content, it had no significant effect on reducing Na. So the mortality of the seedlings or grain yield in K fertilized sodic soils was as good as in control and this could be explained on the basis of lack of any significant difference in Na concentrations in shoots between these two treatments.     

Structure,biochemistry and ecology of entomogenous galls in Selaginella Pal. Beauv. (Selaginellaceae) from India

Abstract

We studied the structure of newly found entomogenous galls in three Indian species of Selaginella, and the biochemical changes during gall development as well as their seasonal abundances in 10 squares of 1.5 m² under two differing habitat conditions, open and covered. Adult wasps (Cynipidae) initiate two types of gall formation by oviposition, spherical galls on vegetative shoots and elongated, club-shaped strobilar galls on reproductive shoots. Galls are anatomically and biochemically different from the unaffected shoots. Vegetative shoot apices bear more galls (84.6%) than reproductive shoot apices (15.4%). Gall frequency is significantly higher in covered (94.8%) than in open habitat (5.2%), and its seasonal peak occurs earlier in the former (43.1% during the rainy season) than in latter habitat (52.8% in autumn). We discuss the relationship between relative species density and gall seasonality as well as the possible role of certain environmental factors that make covered habitats more favorable to the gall inducer.     

Growth of coyote willow and the attack and survival of a mid-rib galling sawfly,Euura sp.

We studied the relationship between variation in age and shoot characteristics of the host plant Salix exigua Nuttall (coyote or sandbar willow) and the attack and survival of Euura sp. (an unnamed leaf-midrib galling sawfly). Variation in shoot characteristics resulted from reduced growth as willow ramets aged. Mean shoot length per ramet and mean longest leaf length per shoot decreased by 95% and 50% respectively between 1- and 9-year-old willow ramets. All measured shoot characteristics-shoot length, longest leaf length, number of leaves per shoot, and mean internode length-were significantly negatively correlated with ramet age (r ² ranged from –0.23 to –0.41). Correlations between shoot characteristics were highly positive, indicating that plants also grew in a strongly integrated fashion (r ² ranged from 0.54 to 0.85). Four hypotheses were examined to explain sawfly attack patterns. The host-plant hypothesis was supported in explaining enhanced larval sawfly survival through reduced plant resistance. As willow ramets aged, the probability of Euura sp. attack decreased over 10-fold, from 0.315 on 1-year-old ramets to 0.024 on 2- to 9-year-old ramets. As shoot length increased, the probability of sawfly attack increased over 100-fold, from 0.007 on shoots <100 mm, to 0.800 on shoots in the 1001–1100 mm shoot length class. These attack patterns occurred even though 1-year-old ramets and shoots >500 mm each represented less than 2% of the total shoots available for oviposition. Host plant induced mortality of the egg/early instar stage decreased by 50% on longer leaves and was the most important factor determining survival differences between vigorous and non-vigorous hosts. Sawfly attack was not determined by the resource distribution hypothesis. Although shoots <200 mm contained 82% of the total leaves available, they contained only 43% of the galls initiated. The attack pattern also was not explained by the gall volume hypothesis. Although gall volume increased on longer shoots, there was no significant variation in mid or late instar mortality over shoot length, as would be expected if food resources within smaller galls were limited. The natural enemy attack hypothesis could not explain the pattern of oviposition since predation was greater on longer shoots and leaves. In addition, larval survival was related to oviposition behavior. Due to a 69% reduction in late instar death and an 83% reduction in parasitism, survival of progeny in galls initiated close to the petiole base was 2.8 times greater than in galls initiated near the leaf tip. A 75% reduction in gall volume over this range of gall positions may account for the observed increases in late instar mortality and parasitism.     

Influence of tree growth rate, shoot size and foliar chemistry on the abundance and performance of a galling adelgid

1. The abundance and performance of the Eastern Spruce Gall Adelgid, Adelges abietis , was evaluated on young, open-grown trees of White Spruce, Picea glauca , whose growth rates had been increased through fertilization or decreased through root-pruning.
2. In general, gall densities were highest on control trees and on mid-crown branches. Reduced galling success on fertilized trees was largely due to higher overwintering mortality of first-generation nymphs. Foliar magnesium, total tannin and total phenol contents were positively, and nitrogen and total monoterpene contents negatively, related to gall density and/or galling success.
3. Although short shoots were more abundant, shoot length was parabolically related to gall density. There was a non-significant parabolic trend between shoot size and galling success and volume. The number and average size of A. abietis females emerging from galls were positively related to gall volume, and realized fecundity was positively correlated to female size. Consequently, fitness was approximately twice as high for nymphs colonizing intermediate-sized than small or large shoots.
4. These results do not support the plant vigour or plant stress hypotheses. The results do, however, agree with predictions of the modified plant stress hypothesis for sucking insects. It is speculated that Adelges abietis lacks the necessary resources for successful gall formation on small shoots and is unable to produce a stimulus large enough to induce gall formation on large shoots.     

Effect of Nitrogen Fertilization and Growth Suppression on Pitch Canker Development on Loblolly Pine Seedlings

One-yr-old loblolly pine seedlings of two half-sib families, grown in sand, were fertilized three times per week with nutrient solution containing 20 μg/ml (low) or 80 μg/ml (high) nitrogen. Nitrogen concentration in the nutrient solution was either constant throughout the experiment, or interehanged after the inoculation of stems or shoots with Fusarium subglutinans, 55 days after initiation of fertilization. Growth was suppressed by a weekly excision of shoots branching from the stem apex. Either high nitrogen nutrition or shoot excision generally enhanced canker elongation on stem inoculated plants; the combination of both was extremely conducive for disease development. With intact plants of family 8–68, interchange of pre-inoculation low nitrogen nutrition with high nitrogen after inoculation enhanced canker elongation and rate of wilt. Nitrogen content varied in wood, bark and needles, as well as with time intervals, but was consistently in accordance with nitrogen level in the nutrient solution. In shoot excised plants, nitrogen content was higher than in the respective treatment without shoot excision. The higher nitrogen nutrient accelerated disease development on inoculated shoots, compared to low nitrogen, on both pine families. With respective treatments, stem cankers were larger and rates of shoots exhibiting lesions or wilt were higher on plants of family 8–68 than on 8–61. It is postulated that the disease enhancing effect associated with higher nitrogen content in stem tissues results from an increased nitrogen availability to the pathogen.     

A nectar-secreting gall wasp and ant mutualism: selection and counter-selection shaping gall wasp phenology, fecundity and persistence

Abstract.

• 1 The natural history of a gall wasp including interactions with inquilines, parasites, and a mutualistic ant are examined. The stability of the system is described from the perspective of influences on gall wasp life history characteristics.
• 2 An exclusion experiment demonstrated that the nectar-secreting gall of Disholcaspis perniciosa mediates a mutualism with the tending ant, Formica obscuripes. Survivorship increased from 0% in the absence of ants to 25.3% in their presence, largely due to the exclusion of inquilines.
• 3 Specialized parasites, Eudecatoma spp., attacked before the ant-gall interaction began, when the developing gall was still beneath the host plant (Quercus gambellii) epidermis and ants were not in attendance. They may select for later developing gall wasps, which benefit by having fewer individuals parasitized. However, counter-selection for earlier development may result from decreased gall wasp size, decreased fecundity, and an increase in gall failures resulting from late development.
• 4 Local persistence of the gall wasp population despite increased pressure from inquilines and parasites was attributed to gall wasp escape in time due to polymorphic emergence resulting from diapause. Most individuals emerge at the end of the summer, but approximately 15% remain in the galls as prepupae for 1–5 years.

     

Micropropagation of <Emphasis Type="Italic">Teucrium fruticans</Emphasis> L., an ornamental and medicinal plant

An efficient protocol for in vitro propagation of the valuable ornamental and medicinal plant Bush germander (Teucrium fruticans L.) was developed through axillary shoot proliferation. A Murashige and Skoog agar medium supplemented with benzylaminopurine (6.6 μM), α-naphthaleneacetic acid (0.053 μM), and sucrose (3%) significantly improved the production of multiple shoots directly from nodal segment explants, resulting in an average of 2.8 shoots per segment with an average of 6.8 nodes per shoot that would be potential newly formed explants. The new shoots were developed without a marked decrease in the average height of the shoots. Shoots treated with 2.5 μM indole-3-butyric acid showed the highest average root number (7.9) and the highest percentage of rooting (94%). Plantlets were hardened off and transferred to jiffy pots for acclimatization under greenhouse conditions, resulting in a 100% survival rate.     

Biomass and elemental uptake in fertilized and unfertilizedBetula papyrifera Marsh. andPopulus grandidentata Michx.

Summary Estimates were made of the above-ground biomass and contents of N, P, K, Ca, Mg, Mn, Na, Fe, Zn, Al, and Cu in fertilized (N 448 kg/ha, P 112 kg/ha, lime 4480 kg/ha) and unfertilized white birch (Betula papyrifera Marsh.) and bigtooth aspen (Populus grandidentata Michx.). For individuals of both species, fertilization increased the average above-ground biomass increment and the N and P content increment by 150 per cent and 300 per cent, respectively, but decreased uptake of Mn and Zn. The allocation of biomass and elements differs not only between species, but within species under untreated and fertilized conditions.     

Diversification in the use of resources by Idarnes species: bypassing functional constraints in the fig–fig wasp interaction

Mutualisms such as the fig–fig wasp mutualism are generally exploited by parasites. We demonstrate that amongst nonpollinating fig wasps (NPFWs) parasitic on Ficus citrifolia, a species of Idarnes galls flowers and another species feeds on galls induced by other wasps killing their larvae. The galling wasp inserts its ovipositor through the fig wall into the fig cavity. The ovipositor then follows a sinuous path and is introduced through the stigma and style of the flower. The egg is deposited between the integument and nucellus, in the exact location where the pollinating mutualistic wasp would have laid its egg. Gall induction is a complex process. In contrast, the path followed by the ovipositor of the other species is straightforward: attacking a larva within a developed gall poses different constraints. Shifts in feeding regime have occurred repeatedly in NPFWs. Monitoring traits associated with such repeated evolutionary shifts may help understand underlying functional constraints. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 114–122.     

Effect of host-plant manipulation by a gall-inducing insect on abundance of herbivores on chestnut trees

We investigated plant-mediated effects of the stem gall wasp, Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), on other herbivores on the chestnut tree Castanea crenata. In the early season, leaves emerged earlier and in greater numbers on galled shoots than on ungalled shoots. On galled shoots the leaf to shoot biomass ratio was lower and the leaves were physically different. In May and June the concentration of nitrogen in leaves was higher on galled shoots than on ungalled shoots. In July, the water content of leaves was lower on galled shoots. In May and June, the number of aphids, Myzocallis kuricola Matsumura (Homoptera: Aphidoidea), on leaves was higher on galled shoots than on ungalled shoots, but the opposite was true at the end of July. Laboratory experiments showed that aphid fecundity and body weight decrease were higher in May and June when aphids fed on leaves on a galled shoot than when they fed on those on ungalled shoots. In contrast, aphid performance in July was greater on ungalled leaves than on galled leaves. Our findings suggest that gall initiation in a chestnut tree affected aphid performance by affecting host plant quality.     

Wolbachia in wasps parasitic on filth flies with emphasis on Spalangia cameroni

The house fly, Musca domestica L., and the stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), are cosmopolitan pests parasitized by a guild of more than two dozen species of wasps. Several species of these wasps have been commercialized as biocontrol agents or are being studied for this purpose. Wolbachia bacteria are known to infect at least some of these wasps and are of interest because infections can dramatically affect insect reproduction. A survey in this parasitoid–fly system detected Wolbachia in 15 of 21 species of wasps and in three of nine species of flies parasitized by these wasps. Phylogenetic analyses using wsp gene sequences identified single isolate infections in most cases. Infections of two and four isolates were detected in Nasonia vitripennis (Walker) and Spalangia cameroni Perkins (Hymenoptera: Pteromalidae), respectively. Laboratory experiments showed infections in S. cameroni to cause an incomplete form of female‐mortality (FM) type cytoplasmic incompatibility (CI). Crosses between uninfected female and infected male partners (♀×♂^w) produced fewer progeny, which had a strong male‐biased sex ratio. Crosses between ♀×♂, ♀^w×♂^w, and ♀^w×♂ produced more progeny, which had a female‐biased sex ratio. Developmental times of progeny were increased when the paternal parent was infected with Wolbachia, regardless of whether the maternal parent was infected or whether offspring developed from fertilized eggs. This result may reflect the action of Wolbachia on components of the seminal fluid that then affect the development of offspring from inseminated females. It is hoped that future studies of Wolbachia in this guild will facilitate the rearing and application of these wasps as biocontrol agents of house fly and stable fly.     

Host range of the European leaf sheath mining midge,Lasioptera donacis Coutin (Diptera: Cecidomyiidae), a biological control of giant reed,Arundo donax L.

The fundamental host range of the arundo leafminer, Lasioptera donacis a candidate agent for the invasive weed, Arundo donax was evaluated. L. donacis collects and inserts spores of a saprophytic fungus, Arthrinium arundinis, during oviposition. Larvae feed and develop in the decomposing leaf sheath channel tissue. Thirty-six closely related and economic grass species along with several key habitat associates were evaluated in no-choice tests. L. donacis and its associated saprophyte completed development only on A. donax, in concurrence with published reports from its native range in Mediterranean Europe. The arundo leafminer feeding leads to premature defoliation, constituting a different mode of attack on the host plant as compared to two previously released insects, the arundo wasp and arundo scale, which feed on shoot tips and rhizomes, respectively. Defoliation of A. donax is expected to increase light penetration into stands of A. donax which increases visibility for law enforcement, reduces the survival of cattle fever ticks, and enhance recovery of the native riparian vegetation along the Rio Grande and other habitats where this weed is invasive.     

Transfer of a chromosomal <Emphasis Type="Italic">Maverick</Emphasis> to endogenous bracovirus in a parasitoid wasp

Bracoviruses are used by parasitoid wasps to allow development of their progeny within the body of lepidopteran hosts. In parasitoid wasps, the bracovirus exists as a provirus, integrated in a wasp chromosome. Viral replication occurs in wasp ovaries and leads to formation of particles containing dsDNA circles (segments) that are injected into the host body during wasp oviposition. We identified a large DNA transposon Maverick in a parasitoid wasp bracovirus. Closely related elements are present in parasitoid wasp genomes indicating that the element in CcBV corresponds to the insertion of an endogenous wasp Maverick in CcBV provirus. The presence of the Maverick in a bracovirus genome suggests the possibility of transposon transfers from parasitoids to lepidoptera via bracoviruses.