Host size,superparasitism and sex ratio in mass-reared <Emphasis Type="Italic">Diachasmimorpha longicaudata</Emphasis>, a fruit fly parasitoid

We analyzed the relationship among host size, superparasitism and sex-ratio in mass reared Diachasmimorpha longicaudata (Hymenoptera: Braconidae). Individual host pupae of Anastrepha ludens (Diptera: Tephritidae) were measured (length and width), and the number of oviposition scars per pupa was used as a reliable indicator of superparasitism. The probability of an emerging parasitoid being a female was positively associated with the number of oviposition scars on the host cuticle, but not with the host size. The number of scars per host pupae from which females emerged was slightly but significantly higher than in those pupae giving raise to males. In D. longicaudata, the influence of host size on sex allocation decisions of individual females seems to be overridden by the level of superparasitism, which itself was positively correlated with pupa length. This suggests that larger pupae could experience a higher number of ovipositions than their smaller counterparts, and that a high level of superparasitism may conduct to a female biased sex ratio. We discuss the relevance of these findings which could provide new elements (e.g., the manipulation of superparasitism) for optimizing the mass rearing of this parasitoid.     

Superparasitism in mass reared Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae), a parasitoid of fruit flies (Diptera: Tephritidae)

Superparasitism frequency and its effects on the quality of mass-reared Diachasmimorpha longicaudata (Ashmead) parasitoids were investigated under laboratory conditions. Percentage of adult emergence, sex ratio, survival, fecundity and flight ability of adult parasitoids that emerged from Anastrepha ludens (Loew) pupae with different levels of superparasitism were determined. A high prevalence of superparasitism was observed. The number of scars per pupa, produced by insertion of the parasitoid ovipositor, ranged from 1 to 30, with an average (±SD) of 8.3 ± 6.2. Adult parasitoid emergence decreased as the level of superparasitism increased. However, the fraction of females rose with increasing superparasitism and the flight ability was lower in adults emerging from pupae with only one scar, compared with adults emerging from superparasitized hosts. Female longevity and fecundity were not affected by superparasitism. Our results support the hypothesis that superparasitism in D. longicaudata might be adaptive, since adults emerging from hosts with moderate levels of superparasitism showed the highest percentage of emergence and there were no significant differences in the other quality control parameters tested. Our findings are relevant to the mass rearing process, where the ratio of hosts to parasitoids can be optimized as well as the distribution of eggs deposited in host larvae. This contributes to efficient mass rearing methods for augmentative biological control programs.     

Discrimination by Coptera haywardi (Hymenoptera: Diapriidae) of hosts previously attacked by conspecifics or by the larval parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae)

Coptera haywardi (Oglobin) is an endoparasitoid of fruit fly pupae that could find itself in competition with other parasitoids, both con- and heterospecific, already resident inside hosts. In choice bioassays, ovipositing C. haywardi females strongly discriminated against conspecifically parasitised Anastrepha ludens (Loew) pupal hosts. They also avoided pupae previously attacked by Diachasmimorpha longicaudata (Ashmead), a larval–prepupal koinobiont endoparasitoid, and the degree of larval-parasitoid superparasitism had no effect on this avoidance. There was no difference in the number of ovipositor insertions when hosts previously parasitised by a conspecific and D. longicaudata were exposed simultaneously. As females aged the degree of host discrimination declined. An ability to discriminate against pupae previously attacked as larvae suggests low levels of both conspecific and heterospecific competition in the field.     

Host discrimination and superparasitism in wild and mass-reared Diachasmimorpha longicaudata (Hym.: Braconidae) females

We compared the oviposition behavior and host discrimination ability of wild and mass-reared Diachasmimorpha longicaudata (Hymenoptera: Braconidae) females parasitizing Anastrepha ludens (Diptera: Tephritidae) larvae. Both kinds of parasitoid females were presented simultaneously with parasitized and non-parasitized larvae in choice tests, and their superparasitism performance was evaluated under a mass-rearing situation. At the time of the test, D. longicaudata had 156 generations under mass-rearing conditions. Our goal was to determine the effect of the mass-rearing process on the foraging decisions of this species. One of the primary findings was the apparent ubiquity of superparasitism by D. longicaudata females. Both types of females showed similar patterns in each of the phases of oviposition behavior evaluated. The only notable differences were among the percentages of transition between behaviors, mainly related to the intensity with which each activity was performed. Under a mass-rearing situation, both strains of females had a similar tendency to increase superparasitism (i.e., number of oviposition scars per puparium and the proportion of superparasitized larvae) over time. The mass-rearing process appears to have induced the selection of more aggressive, fertile and precocious females. Despite these observations, we concluded that the process of adaptation to mass-rearing conditions has not substantially influenced the foraging and ovipositional behaviors in this species.     

Superparasitism strategies by a native and an exotic parasitoid species attacking the Mexican fruit fly,Anastrepha ludens (Diptera: Tephritidae)

Superparasitism refers to the action of parasitoids ovipositing eggs in hosts that are already parasitized; this inevitably results in the elimination of supernumerary larvae in solitary parasitoids. Here, we investigated superparasitism performed by two species of solitary parasitoids on the larvae of Anastrepha ludens (Loew; Diptera: Tephritidae): a native species, Doryctobracon crawfordi (Viereck; Hymenoptera: Braconidae), and an exotic species, Diachasmimorpha tryoni (Cameron; Hymenoptera: Braconidae). Tests were conducted under laboratory conditions evaluating the behaviour of females acting alone (self-superparasitism) or in groups (conspecific superparasitism). Parasitism strategies were different between these two species. In D. crawfordi, the number of first instar larvae found in each dissected host pupa was never greater than two, regardless of the number of oviposition scars observed per pupa. In contrast, there was a positive correlation between the number of oviposition scars and the number of first instar larvae in D. tryoni. The survival and fecundity of D. crawfordi females emerging from pupae with one scar was higher than in females emerging from pupae with more scars. In D. tryoni, the number of oviposition scars did not show deleterious effects on life history traits and was positively correlated with the proportion of emerging females. An understanding of the superparasitism strategy adopted by parasitoid species could be of great interest to augmentative biological control programmes because the mass rearing of natural enemies could be negatively or positively affected by this condition.     

Predation potential of the earwig Euborellia annulipes on fruit fly larvae and trophic interactions with the parasitoid Diachasmimorpha longicaudata

The earwig Euborellia annulipes (Lucas) (Dermaptera: Anisolabididae), a generalist predator, has been observed in fruits infested with fruit fly larvae, which are frequently parasitized by parasitoid wasps. Neither the capacity of earwigs to predate on fruit flies nor intraguild interactions between earwigs and fruit fly parasitoids have been investigated. Here, we studied in laboratory conditions the predation on the fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) by the earwig E. annulipes, and whether parasitism of fruit fly larvae by the parasitoid wasp Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) influences predation by the earwig. We evaluated the predation capacity, functional response and prey preference of E. annulipes for parasitized and non-parasitized fruit fly larvae in choice and no-choice tests. We found that earwigs prey on second- and third-instar larvae and pupae of C. capitata and consumed larger numbers of second-instar larvae, followed by third-instar larvae and pupae. Females prey on larger numbers of fruit flies than did males, regardless of the prey developmental stage, but both sexes exhibited a type II functional response. Interestingly, males killed but did not consume fruit fly larvae more than did females. In no-choice tests, earwig females consumed equal numbers of parasitized and non-parasitized fruit fly larvae. However, in choice tests, the females avoided feeding on parasitized larvae. Subsequent tests with hexane-washed parasitized and non-parasitized larvae showed that putative chemical markings left on fruit flies by parasitoids did not drive the earwig preference towards non-parasitized larvae. These findings suggest that E. annulipes is a potential biological control agent for C. capitata, and that, because the earwig avoids consuming larvae parasitized by D. longicaudata, a combination of the two natural enemies could have an additive effect on pest mortality.     

Contrasting Brood-Sex Ratio Flexibility in Two Opiine (Hymenoptera: Braconidae) Parasitoids of Tephritid (Diptera) Fruit Flies

Mass-rearing of fruit fly parasitoids for augmentative release would be more economical if production could be biased towards females. If sex ratios are ever to be manipulated under rearing conditions it is important to determine if, then understand why, sex ratio flexibility exists. Unequal brood-sex ratios are common in parasitic Hymenoptera and two reasons are generally advanced for such cases: 1) avoidance of Local Mate Competition (LMC) predicts that the number of females exploiting a host-patch can influence the optimal sex ratio of their offspring; and 2) one sex is more likely to develop under a particular set of physical/competitive conditions. We hypothesized that LMC is more often encountered in relatively uncommon species with coarse-grained distributions. As a result, isolated females of such species would be more likely to expect future LMC to be high and to bias offspring sex ratios towards females. We proposed that the opiine braconid Utetes anastrephae is such a coarse-grained species and compared its responses to differences to LMC (isolated females and those paired with a conspecific competitor) with those of another opiine, Diachasmimorpha longicaudata believed to have a finer-grained distribution. Adult sex ratios were mutable in D. longicaudata and U. anastrephae and, as predicted by avoidance of LMC, males were relatively more abundant among the paired females in both species. However, superparasitized hosts yielded relatively more daughters, perhaps because female larvae are superior intrinsic competitors. Contrary to prediction, there was no suggestion that U. anastrephae was more likely to than D. longicaudata to avoid LMC. While these results did not reveal any species differences in sex-allocation patterns or suggest any modifications to the present practice of fruit fly mass-rearing for augmentative release they did provide new information regarding U. anastrephae, a widespread natural enemy of Anastrepha spp. about which relatively little is known.     

Impact of mating status on egg-laying and superparasitism behaviour in a parasitoid wasp

Most parasitoid female wasps can distinguish between unparasitized and parasitized hosts and use this information to optimize their progeny and sex allocation. In this study, we explored the impact of mating on oviposition behaviour (parasitism and self‐ and conspecific superparasitism) on both unparasitized and already parasitized hosts in the solitary parasitoid wasp Eupelmus vuilleti (Crw.) (Hymenoptera: Eupelmidae). Virgin and mated females had the same oviposition behaviour and laid eggs preferentially on unparasitized hosts. The sex ratio (as the proportion of females) of eggs laid by mated females in parasitism and conspecific superparasitism was 0.67 ± 0.04 and 0.57 ± 0.09, respectively. Likewise, females laid more eggs in conspecific superparasitism than self‐superparasitism under our experimental conditions. These experiments demonstrate that E. vuilleti females can (i) discriminate between unparasitized and parasitized hosts and adapt the number of eggs they lay accordingly, and (ii) probably discriminate self from conspecific superparasitized hosts. Finally, mating does not appear to influence the host discrimination capacity, the ovarian function, or the oviposition behaviour.     

Egg allocation of the autoparasitoid encarsia tricolor at different relative densities of the primary host (Trialeurodes vaporariorum) and two secondary hosts (Encarsia formosa and E. tricolor)

Parasitism, offspring sex ratio and superparasitism of the facultative autoparasitoid Encarsia tricolor Foërster (Hymenoptera: Aphelinidae) when given access to arenae with different proportions of the primary host (Trialeurodes vaporariorum (Westwood)) and two species of secondary hosts (E. tricolor and Encarsia formosa Gahan) were studied.Parasitism and offspring sex ratio were not affected by female age in the range 3–10 days old. When the secondary hosts were young E. tricolor pupae, eggs were mostly laid on primary hosts, so the offspring sex ratio was more female-biased than expected, and secondary hosts were not superparasitized at all. When the secondary hosts were fully grown E. formosa larvae, superparasitism was small and offspring sex ratio was more male-biased than expected. E. tricolor females were able to discriminate between hosts previously parasitized by themselves and non-parasitized hosts.     

寄主大小及寄生顺序对蝇蛹佣小蜂寄生策略的影响

寄主大小模型认为寄生蜂后代性比与寄主大小相关,寄生蜂倾向于在大寄主上产出更多雌性后代,在小寄主上产出更多雄性后代.探讨了以家蝇蛹为寄主时,蝇蛹佣小蜂后代产量和性比变化;单次寄生情况下,寄主大小及寄生顺序对寄生蜂后代性比等影响.结果表明,蝇蛹佣小蜂的产卵期为(8.93±3.34)d,单头雌蜂能产雌性后代(34.11±16.34)头和雄性后代(11.04±8.87)头,且雄性百分比为0.24±0.11.随成蜂日龄的增大,寄生蜂产生雄性后代的比率显著增加.蝇蛹佣小蜂在寄生家蝇蛹时,会优先选择寄生个体较大的蛹;在单次寄生的情况下,蝇蛹佣小蜂倾向于在较大的家蝇蛹内产出更多的雌性后代.     

Parasitism by Coptera haywardi and Diachasmimorpha longicaudata on Anastrepha flies with different fruits under laboratory and field cage conditions

Larvae of Anastrepha ludens and A. serpentina that developed in mango and sapodilla fruits, respectively, were exposed to Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) and sequentially exposed as pupae to Coptera haywardi (Oglobin) (Hymenoptera: Diapriidae). Sequential exposure to both parasitoid species contributed to a decrease in fruit fly emergence due to higher levels of parasitism, which varied according to fruit type. In creole mango, D. longicaudata represented the highest percentage of parasitism. C. haywardi parasitism was greater in pupae from Ataulfo mangos and sapodilla, where the pulp size and volume may have acted as a refuge, allowing fly larvae to escape and leaving a greater number of unparasitised pupae available to C. haywardi. Similar results were obtained under field cage conditions, but the level of parasitism by C. haywardi was lower, suggesting that its effectiveness has some limitations under natural conditions. Our results suggest that both species can exert complementary parasitism, which represents an alternative worth to investigate under open field conditions.     

Intrinsic competition between Diachasmimorpha longicaudata and three native species of parasitoids (Hymenoptera: Braconidae: Opiinae) of Anastrepha (Diptera: Tephritidae) fruit flies under laboratory conditions

The effect of intrinsic competition between the exotic parasitoid Diachasmimorpha longicaudata (Ashmead) and the native species Doryctobracon crawfordi (Viereck), Utetes anastrephae (Viereck) and Opius hirtus (Fischer) (all Braconidae: Opiinae) was studied under laboratory conditions. Each native species and D. longicaudata acted as both a resident and an invader, and all species were introduced to the host simultaneously. Diachasmimorpha longicaudata was found to be the most competitive species because it achieved the highest parasitism percentage under all the experimental conditions, but it was also negatively affected by the presence and parasitic activity of the native parasitoids. Utetes anastrephae was the only species that maintained its parasitic rate when all species attacked the available hosts simultaneously. The emergence probability of a female D. longicaudata was positively associated with the increase in the number of scars on the cuticle of the host pupa, but this association was not observed for the native species. It was concluded that D. longicaudata is an intrinsic competitor that is superior to D. crawfordi, U. anastrephae and O. hirtus, whether acting as a resident or an invader, producing a female-biased sex ratio in all the evaluation conditions. Utetes anastrephae was the native species that was least affected by the competitive presence of D. longicaudata, which suggests that it could be used as a complementary biological control agent for Anastrepha fruit flies.     

Superparasitism and host discrimination byEphedrus cerasicola [Hym.: Aphidiidae], an aphidiid parasitoid ofMyzus persicae [Hom.: Aphididae]

Myzus persicae (Sulzer) at different densities (1 to 120 aphids) on a paprika plant in a 1.8 dm³ cage were exposed at 21°C to single females of the parasitoidEphedrus cerasicola Stary. Three different exposure periods were used: 1 hr, 6 hrs, 24 hrs. The aphids were dissected 6 days after parasitization. Superparasitism was measured as number of hosts superparasitized and number of parasitoid larvae per aphid. It attained a maximum around host density=5 and decreased with increasing host density and decreasing exposure time. Almost no superparasitism occurred during the 1st hour. A non-random larval distribution indicated thatE. cerasicola discriminates between unparasitized and parasitized aphids, but probably not between aphids with different numbers of parasitoid eggs. Larvae in superparasitized aphids developed slower than single larvae. The supernumerary larvae died during the 1st instar, probably killed by chemical means since no physical attacks between larvae have been observed.     

Biological attributes of three introduced parasitoids as natural enemies of fruit flies,genus Anastrepha (Diptera: Tephritidae)

The biological attributes of three introduced species of parasitoids which attack the fruit fly Anastrepha ludens were evaluated. Larvae and eggs of A. ludens were exposed to larval parasitoids Diachasmimorpha longicaudata and D. tryoni and the egg parasitoid Fopius arisanus. Parasitoid longevity and fecundity were determined using larvae and eggs of A. ludens. Likewise, the parasitism rates of these parasitoid species in infested host fruits were recorded. The intrinsic rate of increase for F. arisanus was 0.1019 followed by D. tryoni with a rate of 0.1641 and D. longicaudata with the highest rate of 0.2233. Although F. arisanus females had the highest levels of fecundity, only 50% of them remained alive until reproductive age. These results in combination with the longer generation time (in comparison with D. longicaudata and D. tryoni), can be considered as the most important factors explaining F. arisanus reduced rate of increase. However, we note that oviposition activity caused egg mortality which reduced Anastrepha egg hatch by ca. 20%. This result suggests that F. arisanus has a high potential as a natural enemy of A. ludens, in accordance with our research efforts to develop a new F. arisanus strain specialized for development in Anastrepha eggs. The results show that D. tryoni is not a good candidate for biological control of Anastrepha. Meanwhile, D. longicaudata continues to be the most important exotic parasitoid for suppression of Anastrepha fruit fly populations.     

The Bionomics ofCoptera Haywardi(Ogloblin) (Hymenoptera: Diapriidae) and Other Pupal Parasitoids of Tephritid Fruit Flies (Diptera)

The endoparasitoidCoptera haywardi(Ogloblin) (Diapriidae) was discovered in Mexico attacking the pupae of the Mexican fruit fly,Anastrepha ludens(Loew). Typically, parasitoids of Diptera Cychlorrhapha pupae develop as ectoparasitoids and are generalists that attack hosts in a number of families. Aspects of the bionomics ofC. haywardiwere compared to those of two chalcidoid ectoparasitoids,Dirhinus himalayanusWestwood andSpalangia geminaBoucek.C. haywardideveloped in three genera of Tephritidae, but not in species of other families. The two species of chalcidoids developed in all the calypterate and acalypterate hosts to which they were exposed. In an olfactometerC. haywardipreferredAnastrepha suspensa(Loew) pupae, while the chalcidoids preferred the pupae ofMusca domestica L.This preference inS. geminawas diminished in insects that had been reared onA. suspensa. C. haywardioviposited in theA. suspensapupae that had been previously parasitized by the braconidDiachasmimorpha longicaudata(Ashmead). However, it completed development only in unparasitized pupae. Mortality of the primary parasitoid due toD. himalayanuswas approximately two-thirds the mortality inflicted on the host fly.S. geminadid not discriminate between parasitized and unparasitized pupae ofA. suspensaand developed in both.C. haywardiappears to have a more restricted host range relative to chalcidoid pupal parasitoids and this may be due to its endoparasitic development.     

Host discrimination modulates brood guarding behaviour and the adaptive superparasitism in the parasitoid wasp Trissolcus semistriatus (Hymenoptera: Scelionidae)

Because hosts utilized by parasitoids are vulnerable to further oviposition by conspecifics, host guarding benefits female wasps. The present study aims to test whether female adults regulate brood guarding behaviour by host discrimination in a solitary parasitoid Trissolcus semistriatus by presenting an intact or parasitized host egg mass to a female adult. Virgin females without oviposition experience have host discrimination ability, which enables them to adjust the number of eggs laid in the hosts. Mating experience increases superparasitism by female adults, whereas mated females achieve a higher discrimination ability as a result of oviposition experience and show a lower superparasitism rate. As expected, females exhibit brood guard after parasitizing an intact host egg mass, whereas those females visiting a previously parasitized host egg mass, do not. Because the survival of eggs in superparasitized hosts is relatively low, regulating brood guarding behaviour by host discrimination is adaptive for female wasps.     

Superparasitism and host size effects in Oomyzus sokolowskii, a parasitoid of diamondback moth

Many aspects of a parasitoid's biology may be affected by its host. Host size, for example, could affect parasitoid fitness, especially in gregarious parasitoids, in which the resource is used by multiple siblings. Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae) is a gregarious larval–pupal endoparasitoid of the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), a major pest of crucifers worldwide, and is able to superparasitize the host. This study focuses on the hypothesis that because resource availability is higher in larger hosts, parasitoids developing in larger hosts will fare better. However, superparasitized hosts are expected to yield larger numbers of parasitoid offspring of smaller body size. Results showed that superparasitism increased the number of parasitoid offspring produced per host and increased offspring longevity, but decreased offspring body size. However, developmental time and sex ratio of parasitoid offspring was similar among hosts parasitized once, twice, or three times. Regardless of superparasitism, parasitoids emerging from larger hosts that were fed honey solution lived longer than similarly fed progeny from smaller hosts (36.4 vs. 22.1 days). The results partially support the hypothesis that Oomyzus gained fitness from an increase in host size; moreover, superparasitism seems advantageous for Oomyzus due to increased offspring numbers and longevity.     

Mutual interference in the mass-reared fruit fly parasitoid,Diachasmimorpha longicaudata (Hymenoptera: Braconidae)

Diachasmimorpha longicaudata is a solitary endoparasitoid produced in Mexico for the biological control of Anastrepha fruit flies (Diptera: Tephritidae). We studied the effect of mutual interference among conspecific foraging females to better understand the parasitoid-host dynamics established in the mass-rearing system of this species. We used a constant host availability of 60 third instar larvae of Anastrepha ludens (per oviposition unit type Petri dish) that were individually exposed for 3 h to 1, 2, 4, 8, 10, 14, and 20 D. longicaudata females, seven days old without oviposition experience. The following parameters were evaluated: total number of attacked hosts (i.e., larvae with at least one oviposition scar), number of attacked hosts per female, adult emergence percentage, and female proportion. We also performed a second assay at mass-rearing level, contrasting the current proportion used in mass-rearing (~?two host larvae per female) with the alternative treatments (5 and 7.5 host larvae per female). Results showed that the density of females foraging on a patch exhibits an inverse relationship to the number of hosts attacked by one female. The highest values for adult emergence (73.4%), patch exploitation (94.6%), and female proportion (0.86) were obtained in the treatments with 7.5, 6, and 3 host larvae per female, respectively. Under mass-rearing conditions, we found that a lower density of females per cage (~?five larvae per female) reduced superparasitism levels without affecting adult emergence and the proportion of females. This suggests that the mass-rearing efficiency of D. longicaudata could be improved by reducing the density of foraging females.

     

Fitness consequences of superparasitism and mechanism of host discrimination in the stemborer parasitoid Cotesia flavipes

The fitness consequences of superparasitism and the mechanism of host discrimination in Cotesia flavipes, a larval parasitoid of concealed stemborer larvae was investigated. Naive females readily superparasitized and treated the already parasitized host as an unparasitized host by allocating the same amount of eggs as in an unparasitized host. However, there was no significant increase in the number of emerging parasitoids from superparasitized hosts due to substantial mortality of parasitoid offspring in superparasitized hosts. Furthermore, the developmental time of the parasitoids in a superparasitized host was significantly longer than in a singly parasitized host and the emerging progeny were significantly smaller (body length and head width). Naive females entered a tunnel in which the host was parasitized 4 h previously and accepted it for oviposition. Experienced females (oviposition experience in unparasitized host) refused to enter a tunnel with a host parasitized by herself or by another female. In experiments where the tunnel and/or host was manipulated it was demonstrated that the female leaves a mark in the tunnel when she parasitizes a host. The role of patch marking in C. flavipes is discussed in relation to the ecology of the parasitoid.     

Effect of <Emphasis Type="Italic">Diachasmimorpha longicaudata</Emphasis> releases on the native parasitoid guild attacking <Emphasis Type="Italic">Anastrepha</Emphasis> spp. larvae in disturbed zones of Chiapas,Mexico

We evaluated the effect of augmentative releases of Diachasmimorpha longicaudata (Ashmead), on the native parasitoid guild of Anastrepha spp. over a two year period in zones adjacent to mango commercial orchards in Chiapas, Mexico. We chose two 15 ha working zones, 15 km apart, harbouring fruit fly hosts of varying densities without chemical control. In 2013, parasitoids were released in zone “A” while zone “B” served as control. In 2014 zones were exchanged. As expected, releases of D. longicaudata significantly increased total parasitism, from around 0.5–5% to over 22%, but annual parasitism by native parasitoids was only significantly affected in zone “A”. The numbers of native parasitoids were higher in zone “A” in both years, and diversity (H′) was not affected by D. longicaudata releases in both zones. Our results suggest that releases of D. longicaudata affect the relative abundance but not the species richness of native parasitoids.