Olfactory response of three parasitoid species (Hymenoptera: Braconidae) to volatiles of guavas infested or not with fruit fly larvae (Diptera: Tephritidae)

The olfactory responses of the native parasitoids Doryctobracon areolatus (Szépligeti) and Asobara anastrephae (Muesebeck) and of the exotic parasitoid Diachasmimorpha longicaudata (Ashmead) to guava (Psidium guajava L.) infested or not with fruit fly larvae were evaluated. D. areolatus and D. longicaudata females responded to the odors of uninfested rotting guavas, although D. areolatus was also attracted to fruits at the initial maturation (turning) stage. The females of these species recognized the volatiles of guavas containing Ceratitis capitata (Wied.) larvae. However, in bioassays involving fruits with larvae of different instars, D. longicaudata females were not able to separate between fruits containing C. capitata larvae at the initial instars and larvae at the third instar. In the evaluations of volatiles released by guavas containing C. capitata and Anastrepha fraterculus (Wied.) larvae, the D. longicaudata females were oriented toward the volatiles of fruits containing both host species, but differed significantly from volatiles of guavas containing C. capitata larvae. The D. areolatus females also showed responses to both species, although with a preference for volatiles of fruits containing A. fraterculus larvae. The A. anastrephae females were oriented toward the odors of fruits infested with both fruit fly species. In the shade house, D. longicaudata females were oriented to volatiles of rotting fruits containing larvae or not, but could not significantly differentiate between hosts. D. areolatus females were not attracted toward fruits on the ground in the shade house, regardless of host, suggesting that this parasitoid does not forage on fallen fruits.     

Intrinsic competition between resident and invasive parasitoids (Hymenoptera: Braconidae) that attack the West Indian fruit fly Anastrepha obliqua under field conditions

We evaluated under semi-field conditions the intrinsic competition between Diachasmimorpha longicaudata (Ashmead), as an invasive parasitoid, and Doryctobracon areolatus (Szépligeti) and Utetes anastrephae (Viereck) (all Hymenoptera: Braconidae) as resident parasitoids, as well as that between U. anastrephae as an invader and D. areolatus as a resident. The percentage of live D. areolatus larvae decreased by 39.8% and 29.4% following attack by D. longicaudata and U. anastrephae as invasive parasitoids, respectively. Likewise, the parasitism percentage of D. areolatus decreased by 31.5% and 60.8% under competition with the invasive parasitoids D. longicaudata and U. anastrephae, respectively. Parasitism by D. longicaudata decreased by 44.6% and 41.6% in the presence of the residents D. areolatus and U. anastrephae, respectively, while parasitism of U. anastrephae was only affected when this species was a resident. We concluded that D. areolatus is an inferior intrinsic competitor and that U. anastrephae resists the competitive presence of D. longicaudata.     

Parasitism of fruit fliesCeratitis capitata andAnastrepha SPP. [Diptera: Tephritidae] in Guatemala

In a 4-year surveyDoryctobracon crawfordi Viereck andBiosteres longicaudatus Ashmead were the most common parasitoids recovered from bothCeratitis capitata (Wiedemann) andAnastrepha spp. Other braconids recovered from both genera wereD. areolatus Szepligeti,Bracanastrepha anastrephae (Viereck), and a Cynipid. Combined parasitization in both generally by ranged from 0.04 to 7.95% (Av. 1.5%). The numbers were particularly low in economically important fruit crops such as coffee, orange, and peach. Combined parasitoid population was correlated with the combined fruit fly infestation at 5 elevation strata.      

Native parasitoids associated with the genusAnastrepha (Dipt.: Tephritidae) in Los Tuxtlas,Veracruz, Mexico

In this paper we record the native parasitoids associated withAnastrepha fruit flies collected in a native tropical community from Los Tuxtlas, Veracruz, Mexico. A total of 1600 puparia ofAnastrepha were recovered from infested fruits of ten different host plants. From these puparia we obtained 218 Hymenopteran parasitoids representing the following species:Doryctobracon areolatus (Szépligeti),Utetes (Bracanastrepha) aff.anastrephae (Viereck),Doryctobracon crawfordi (Viereck),Opius hirtus (Fischer),Microcrasis n. sp.,Nealiolus n. sp. (all Braconidae);Odontosema n. sp. andLopheucoila sp. (Cynipidae). The most abundant and frequently encountered parasitoid species observed during this study wasD. areolatus, representing 59.2% of all recovered parasitoids. The analysis of different infestation rates in fruits regarding to degree of parasitization in theseAnastrepha species suggest they are not correlated, meanwhile some host plant characteristics such as fruit size, could play an important role in influencing rates of parasitization.     

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.     

The Distributions of Parasitoids (Hymenoptera) of Anastrepha Fruit Flies (Diptera: Tephritidae) along an Altitudinal Gradient in Veracruz, Mexico

In the state of Veracruz, Mexico, fruits from 38 sites at various altitudes were collected monthly over a period of 2 years, and the tephritid fruit flies of the genus Anastrepha and associated parasitoids that emerged from these fruits were identified and counted. Of the 26 species of fruits that contained Anastrepha larvae, 18 species also contained a total of 10 species of Anastrepha parasitoids. These consisted of 4 native and 1 exotic species of opiine braconid larval–pupal parasitoids, 2 native species of eucoilid larval–pupal parasitoids, 1 exotic species of eulophid larval–pupal parasitoid, 1 exotic species of pteromalid pupal parasitoid, and 1 native species of diapriid pupal parasitoid. Overall parasitism (including flies from fruit species that bore no parasitoids) was 6% and was greatest, 16%, at 600–800 m in altitude. The relative contributions of individual parasitoid species to overall parasitism were frequently influenced by both the altitude (and correlated changes in temperature and precipitation) and the species of plant in which the Anastrepha larvae were found. This was particularly the case among the more abundant and widespread Braconidae. To distinguish the role of altitude from that of the distributions of the host plants, these braconids were examined in 4 individual species of fruit that grew over a broad range of altitudes. In guava (Psidium guajava L.) and “jobo” (Spondias mombin L.) the parasitoid Doryctobracon areolatus (Szepligeti) was relatively more common at low altitudes. Its congener, Doryctobracon crawfordi (Viereck), was relatively more abundant at high altitudes in sour orange (Citrus aurantium L.). Utetes anastrephae (Viereck) became relatively more common at higher altitudes in S. mombin, whereas Diachasmimorpha longicaudata (Ashmead) tended to become relatively rare at the highest altitudes in C. aurantium, but increased at high altitudes in P. guajava compared to other braconids. Different altitudinal patterns of abundance in different fruits suggests the importance of both biotic and abiotic factors in parasitoid distributions. We discuss the effect of an expanding agricultural frontier on parasitoid abundance and relate our findings to the design of a fruit fly biological control program that tailors mass releases to parasitoid climate preferences.     

Inter‐specific competition and competition‐free space in the tephritid parasitoids Utetes anastrephae and Doryctobracon areolatus (Hymenoptera: Braconidae: Opiinae)

相似文献   

Effect of host diet and adult parasitoid diet on egg load dynamics and egg size of braconid parasitoids attacking Anastrepha ludens

The quantity and quality of host nutrients can affect fitness‐related traits in hymenopteran parasitoids, including oogenesis. The present study tested the prediction that a high host quality will influence oogenesis‐related traits positively in synovigenic parasitoids, and that a high‐quality adult parasitoid diet can positively affect the same parameters, potentially compensating for development on low‐quality hosts. Four braconid parasitoid species with contrasting life histories are reared on a low‐quality diet [Anastrepha ludens Loew (Diptera: Tephritidae) larvae reared on mango] or a high‐quality (artificial) diet. Adult parasitoids are provided with a high‐quality (honey ad libitum), moderate‐quality (honey every other day) or low‐quality (guava pulp) diet. Generalist species that encounter high variation in host quality naturally are predicted to be more flexible in dealing with nutrient shortfalls than specialist species. By contrast to the predictions, low‐quality hosts yield parasitoids with higher egg loads in two species: Opius hirtus Fisher and Diachasmimorpha longicaudata Ashmead. However, as predicted, a high‐quality adult diet exerts a positive effect on egg load (Utetes anastrephae Viereck), egg size (Doryctobracon crawfordi Viereck) and egg maturation rate (D. longicaudata, O. hirtus and U. anastrephae). The generalist D. longicaudata varies in egg load and maturation rate depending on host quality and adult diet, respectively. Evidence of the combined effect of both factors on parasitoid fertility is presented for the specialist O. hirtus. The theoretical and practical implications of these findings are discussed.     

Effects of a fruit and a host-derived compound on orientation and oviposition in Utetes anastrephae,a little studied opiine braconid (Hymenoptera) parasitoid of Anastrepha spp. fruit flies (Diptera: Tephritidae)

Augmentative biological control of tephritid fruit flies would benefit from: (1) synthetic attractants to monitor the survival and dispersal of released parasitoids and (2) synthetic oviposition stimulants to reduce production costs of parasitoid species that are now prohibitively costly to mass-rear. Utetes anastrephae (Viereck) is a widespread and sometimes common opiine braconid parasitoid of several pest Anastrepha spp. Despite its host range, distribution and abundance, it has attracted relatively little research and little is known of its chemical ecology. Its orientation was determined towards two chemical cues hypothesised to be useful at two spatial scales: (1) limonene derived from fruit is presumably abundant and widely dispersed and might identify from a distance patches of potentially host-containing fruit; and (2) para-ethylacetophenone (PEA), a volatile emitted by a number of tephritid larvae, presumably in relatively small amounts, and which could serve as short-range cue or oviposition stimulant. Various concentrations of limonene proved attractive to both females and males, perhaps to the later as a means of locating females accumulated in the vicinity of limonene-emitting host plants. PEA at the concentrations tested did not influence oviposition in U. anastrephae, although it did so for Diachasmimorpha longicaudata (Ashmead), another opiine tephritid parasitoid, previously known to respond to PEA and included in the experiment as a positive control. Limonene at the concentrations tested had no effect on oviposition in either species. These results advance efforts to synthesise attractants and oviposition stimulants for alternative candidates for augmentation such as U. anastrephae.     

Parasitoid hymenopterans of Costa Rica: Geographical distribution of the species associated with fruit flies [Diptera: Tephritidae]

The geographical distribution of the parasitoid species associated with fruit flies in Costa Rica is presented. In a study of 319 fruit samples infested with larvae of fruit flies, collected from 135 localities, 8 parasitoid species were recovered from 11.0% of the fruit samples. Two species are considered to be indigenous, two were introduced for the biological control ofCeratitis capitata (Wiedemann) in this country, at least 3 unidentified species of eucoiline cynipoids and one species of uncertain origin was found for the first time. The identified parasitoids were:Doryctobracon crawfordi (Viereck) (indigenous),D. areolatus (Szépligeti) (indigenous),Biosteres longicaudatus Ashmead (introduced),Aceratoneuromyia indica (Silvestri) (introduced) andTrichopria sp. (indigenous?). The introduced species were more frequently associated withAnastrepha spp. than withC. capitata. The need for systematic monitoring of populations of released parasitoid species is suggested.     

Anastrepha ludens (Loew) (Diptera: Tephritidae) larvae irradiated at higher doses improve the rearing of two species of native parasitoids

Irradiation doses 40, 80, 120 and 160 Gy were used on 6-, 7-, 8- and 9-days-old Anastrepha ludens (Loew) (Diptera: Tephritidae) larvae. The larvae from the different age groups irradiated with different doses were exposed separately to Neotropical-native Doryctobracon crawfordi (Viereck), Utetes anastrephae (Viereck) and the Asian introduced Diachasmimorpha longicaudata (Ashmead) parasitoids (Hymenoptera: Braconidae). A significant increment in parasitoid emergence directly related to radiation increment on parasitoids D. crawfordi and U. anastrephae was observed. This effect was higher on irradiated young larvae; in D. longicaudata, emergence increment was related to age of larva but not with radiation doses. Similar results were obtained for sex ratio. Host larva weight increased with age, and irradiation had no effect on gaining weight of growing larvae. The host larval mortality 72 hr after exposition had an inverse relationship regarding to its age, although it did not have a negative effect as regards radiation doses. Immature stages of parasitoid/larva (>1 = superparasitism) were higher in 8-days-old larvae parasitized by D. Longicaudata, while in D. crawfordi and U. Anastrephae, superparasitism was absent (<1 immature stage per host larva). Superparasitism was not affected by increased radiation dose. No levels of melanin were detected as indicators of immunological reactions. However, these results are considered to be closely related to the lessening of these reactions due to irradiation. The positive relationship between emergence and irradiation dose to host larvae was present in native species D. crawfordi and U. anastrephae, but absent for exotic D. longicaudata. The data presented here are of great relevance for cost effective mass rearing of these parasitoids.     

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.     

Flight Tunnel Responses of Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) to Olfactory and Visual Stimuli

Cohorts of mass-reared, naive Diachasmimorpha longicaudata, parasitoids of tephritid fruit flies, were released in a laminar airflow wind tunnel to study their responses to visual and olfactory stimuli associated with their host habitat. Parasitoids were five times more likely to land on yellow plastic spheres emitting the odor of ripe, guava fruit (Psidium guajava L.) than to spheres emitting clean air. The rate of landing was not modified by the presence of green artificial leaves adjacent to the spheres in the tunnel or by the inclusion of green leaf volatiles emanating with the guava odors. However, hovering activity was twice as frequent around spheres adjacent to artificial leaves than around isolated spheres. Oviposition activity on spheres emitting guava odor was not affected by the presence of artificial leaves nor by green leaf volatiles. This suggests that inexperienced D. longicaudata may be instinctively attracted to foliage and to fruit odor but that landing (arrestment) and oviposition are influenced more by odor than by the appearance of fruit or foliage. D. longicaudata are not instinctively attracted to larvae of Bactrocera dorsalis in the absence of host-habitat stimuli. More wasp activity occurred around oviposition units containing larvae if the odor of ripe/overripe guava was present. Successful wasp reproduction occurred only in units with guava odor.     

Effect of Two Opiine Parasitoids (Hymenoptera: Braconidae) Introduced for Fruit Fly Control on a Native Hawaiian Tephritid,Trupanea dubautiae(Diptera: Tephritidae)

Diachasmimorpha longicaudata(Ashmead) andPsyttalia fletcheri(Silvestri) are opiine parasitoids introduced into Hawaii for control of the Oriental fruit fly,Bactrocera dorsalis(Hendel) and the melon fly,Bactrocera cucurbitae(Coquillett), respectively. Both species have recently been mass-reared and released for research in augmentative biocontrol programs. Laboratory and field sleeve cage experiments were conducted to investigate the potential impact of mass-producedD. longicaudataandP. fletcherion a native Hawaiian tephritid,Trupanea dubautiae(Bryan), infesting the flowerheads of the native composite shrubDubautia raillardioidesHillebrand. Gravid females ofD. longicaudataandP. fletcheriwere confined with bloomingD. raillardioidesflowerheads infested with late instarT. dubautiae.BothD. longicaudataandP. fletcherilacked positive oviposition responses toT. dubautiaelarvae in infested flowerheads and caused neither parasitism nor mortality to the flies. However, when larvae were removed from the flowerheads and presented in screened dishes containing artificial diet of the parasitoids' normal rearing hosts (B. dorsalisandB. cucurbitae), bothD. longicaudataandP. fletcherireadily oviposited in the test larvae. Oviposition byD. longicaudatadid not significantly affect the percentage pupation ofT. dubautiae,but did reduce the emergence of adult flies. Oviposition byP. fletcherisignificantly reduced both pupation and adult fly emergence. All progeny of both parasitoid species died as eggs or first-instar larvae. Results from our experiments demonstrate that biological control programs targeted against frugivorous tephritid pests byD. longicaudataandP. fletcherihave no harmful impact on flowerhead-infestingT. dubautiae.     

Biological Control of Anastrepha spp. (Diptera: Tephritidae) in Mango Orchards through Augmentative Releases of Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae)

Diachasmimorpha longicaudata (Ashmead) parasitoids were released by air on a weekly basis over 1600 ha of commercial mango orchards, backyard orchards, and patches of native vegetation, at a density of ca. 940 parasitoids/ha. Releases were made during 2 consecutive years, beginning at flower onset and lasting until the end of the production cycle. Two areas, 7 km apart, were compared. In one area parasitoids were released, whereas the other area was used as a control. During the 2nd year treatments were reversed. Fruit was sampled in commercial mango orchards and in backyard orchards to assess levels of parasitism in fruit fly larvae. Highly significant differences in percentage parasitism were found in release and control zones in backyard orchards. Furthermore, trapping results indicated that D. longicaudata releases were associated with ca. 2.7-fold suppression of Anastrepha spp. populations in backyard orchards. Results suggest that suppression might be affected by environmental conditions and by the parasitoid:fly ratio achieved. Anastrepha obliqua McQuart populations were suppressed more effectively by use of parasitoids than those of Anastrepha ludens Loew, perhaps due to the type of host fruits used by each species. Augmentative parasitoid releases in marginal areas surrounding commercial orchards (backyard orchards, wild vegetation) can substantially suppress fly populations. Through this approach, the number of flies that later move into commercial orchards can be significantly reduced. Such a strategy, when combined with sound orchard management schemes, can allow growers to produce clean fruit without the need to resort to the widespread use of insecticides.     

Effect of continuous rearing on courtship acoustics of five braconid parasitoids,candidates for augmentative biological control of <Emphasis Type="Italic">Anastrepha</Emphasis> species

The courtship acoustics of five species of parasitoid wasps (Hymenoptera: Braconidae), potential candidates for augmentative biological control of Anastrepha (Schiner) species (Diptera: Tephritidae), were compared between recently colonized individuals and those continuously reared 70–148 generations. During courtship, males of these parasitoid species fan their wings and produce a series of low amplitude pulses. The first series of 15 or more continuous courtship pulses was used to measure the pulse duration, frequency, and interpulse interval (IPI) from the beginning, middle, and end of the pulse series. Each parameter was compared between young and old colonies, and among species. Several differences in courtship acoustics were detected in colonies that had been continuously reared. The pulse duration at the end of the pulse series was longer in old colonies for Doryctobracon crawfordi (Viereck) (Hymenoptera: Braconidae), but shorter for old colonies of Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae). The IPI of the middle pulse was shorter in old colonies of Opius hirtus (Fischer) (Hymenoptera: Braconidae), and was also shorter at the last pulse for old colonies of both Utetes anastrephae (Viereck) (Hymenoptera: Braconidae) and D. longicaudata. The duration of the middle pulse distinguished the three native species, and separated the two introduced species from each other. We discuss our findings in light of their biological and applied implications, particularly those dealing with quality control of mass-reared parasitoids.     

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.     

Pupal and larval-pupal parasitoids (Hymenoptera) obtained fromAnastrepha Spp. andCeratitis capitata (Dipt.: tephritidae) pupae collected in four localities of Tucuman province,Argentina

Pupal and larval-pupal parasitoids were obtained from 5 % of the 1,413 tephritid puparia collected in four localities of the Tucumán province, Argentina, from April, 1991 to April, 1993.Ceratitis capitata (Wiedemann) was attacked byPachycrepoideus vindemmiae (Rondani) (Pteromalidae), a pupal parasitoid, andAganaspis pelleranoi (Brèthes) (Eucoilidae), a larval parasitoid.Anastrepha spp. were attacked byDoryctobracon areolatus (Szépligeti) (Braconidae), a larval parasitoid, and also byA. pelleranoi. Information about parasitism, percentage of emergence of tephritid species and pupal viability in different localities is provided.     

Effect of different dietary resources on longevity, carbohydrate metabolism, and ovarian dynamics in two fruit fly parasitoids

A growing body of literature reports the importance of non-prey food sources in boosting fitness of arthropod natural enemies, thus further contributing to their pest control efficacy. Although resources such as nectar, pollen, or honeydew have received a fair amount of research attention, little is known about the role of fruit juices. Under natural conditions, Tephritid fruit fly parasitoids enjoy ample access to fallen or damaged fruits and their saccharide-rich juices, and wasp fitness can potentially benefit in multiple ways from access to these resources. In this study, we compared the effect of fruit juice with other food resources on multiple fitness parameters in parasitoids that commonly forage on fallen, damaged fruits: the braconid Diachasmimorpha longicaudata and figitid Aganaspis pelleranoi. Parasitoids were subject to simple or combined diets of guava juice (Psidium guajava), honey and pollen, and their effect on wasp longevity, ovarian dynamics and (body) carbohydrate levels was assessed. For both species, adult longevity proved lowest on simple diets of water, guava juice, or pollen, while greatest longevity was attained on honey or combined diets. For D. longicaudata, egg load did not differ between the various diets, while A. pelleranoi egg load was higher for individuals that had access to honey or pollen, but did not differ between newly emerged wasps and those fed guava juice. In both parasitoid species, total sugars, fructose, and glycogen levels were highest in wasps fed with honey or combined diets and lowest under (simple) guava juice, pollen, or water diets. In conclusion, D. longicaudata and A. pelleranoi attained superior longevity and body nutrient levels with access to high-sucrose sugar sources, such as honey, but benefited comparatively little from access to guava juice. Our work hints the role of high-sucrose foods such as (extra-) floral nectar or artifical sugar sprays in boosting fitness of fruit fly parasitoids. We further discuss the relevance of these findings for fruit fly biological control, in crops such as guava.     

Natural establishment of a parasitoid complex on Bactrocera latifrons (Diptera: Tephritidae) in Hawaii

Bactrocera latifrons (Hendel) (Diptera: Tephritidae) is the most recent of four tephritid fruit fly species accidentally introduced into Hawaii. Although parasitoids have been released against other tephritid fruit fly species and have shown partial success in Hawaii, no parasitoids were released until 2004 to suppress populations of B. latifrons. The present study was conducted to document the parasitoid complex that has naturally established against B. latifrons in Hawaii and to assess whether there is a need for improving the biological control of this species. Based on ripe turkeyberry (Solanum torvum Sw) fruit collections over three consecutive years B. latifrons was the dominant tephritid fruit fly infestating turkeyberry at all four sites surveyed, across three major islands in Hawaii. The overall percentage parasitism of B. latifrons ranged from a low of 0.8% (Hana, Maui) to a high of 8.8% (Kahaluu, Oahu). Five primary parasitoid species were recovered from individually held B. latifrons puparia: Fopius arisanus (Sonan), Psyttalia incisi (Silvestri), Diachasmimorpha longicaudata (Ashmead), D. tryoni (Cameron), and Tetrastichus giffardianus Silvestri. F. arisanus was the predominant parasitoid at three of the four sites. Low levels of parasitism suggest that there is a need to improve biological control of B. latifrons, to minimize chances of this species causing economic impacts on crop production in Hawaii. We discuss the possibility of improving biological control of B. latifrons through augmentative releases of F. arisanus or introduction and release of specific and efficient new parasitoid species.