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.     

Larval feeding substrate and species significantly influence the effect of a juvenile hormone analog on sexual development/performance in four tropical tephritid flies

The juvenile hormone (JH) analog methoprene reduces the amount of time it takes laboratory-reared Anastrepha suspensa (Caribbean fruit fly) males to reach sexual maturity by almost half. Here, we examined if methoprene exerted a similar effect on four other tropical Anastrepha species (Anastrepha ludens, Anastrepha obliqua, Anastrepha serpentina and Anastrepha striata) reared on natural hosts and exhibiting contrasting life histories. In the case of A. ludens, we worked with two populations that derived from Casimiroa greggii (ancestral host, larvae feed on seeds) and Citrus paradisi (exotic host, larvae feed on pulp). We found that the effects of methoprene, when they occurred, varied according to species and, in the case of A. ludens, according to larval host. For example, in the case of the two A. ludens populations the effect of methoprene on first appearance of male calling behavior and number of copulations was only apparent in flies derived from C. greggii. In contrast, males derived from C. paradisi called and mated almost twice as often and females started to lay eggs almost 1 day earlier than individuals derived from C. greggii, but in this case there was no significant effect of treatment (methoprene) only a significant host effect. There were also significant host and host by treatment interactions with respect to egg clutch size. A. ludens females derived from C. paradisi laid significantly more eggs per clutch and total number of eggs than females derived from C. greggii. With respect to the multiple species comparisons, the treatment effect was consistent for A. ludens, occasional in A. serpentina (e.g., calling by males, clutch size), and not apparent in the cases of A. obliqua and A. striata. Interestingly, with respect to clutch size, in the cases of A. ludens and A. serpentina, the treatment effect followed opposite directions: positive in the case of A. ludens and negative in the case of A. serpentina. We center our discussion on two hypotheses (differential physiology and larval-food), and also interpret our results in light of the life history differences exhibited by the different species we compared.     

Fruit infesting tephritids [Dipt.: Tephritidae] and associated parasitoids in Chiapas,Mexico

A total of 1,302 parasitoids representing 8 species and 4 families were recovered from 9,818 fruit fly host fruits sampled. The most common parasitoid species wasDiachasmimorpha longicaudata (Ashmead). Average percent parasitism ranged between 0.44 and 29.23%. Parasitoid emergence data indicate thatAnastrepha ludens (Loew),A. obliqua (Sein),A. serpentina (Wiedeman),A. striata (Schiner) andToxotrypana curvicauda (Gerstaecker) were subject to parasitism. We provide information on the population fluctuation ofAnastrepha ludens, A. obliqua, A. serpentina, A. distincta (Greene),A. striata, A. fraterculus (Wiedeman),A. chiclayae (Greene),A. montei (Costa Lima),A. leptozona (Hendel) andA. tripunctata (Wulp).Anastrepha ludens andA. obliqua were the most common species, representing 95.3% of all fruit fly species caught in McPhail traps.      

<Emphasis Type="Italic">Fopius arisanus</Emphasis> oviposition in four <Emphasis Type="Italic">Anastrepha</Emphasis> fruit fly species of economic importance in Mexico

We studied the oviposition performance of Fopius arisanus (Sonan) (Hymenoptera: Braconidae) attacking eggs of four fruit flies of the genus Anastrepha Schiner (Diptera: Tephritidae) under laboratory conditions. The complete process of oviposition on an individual egg of Anastrepha ludens (Loew) lasts in average 85.4 ± 2.9 s, including a tremor (25.8 ± 1.03 s) observed in the middle of this process related to the egg’s descent. The average parasitism of A. ludens egg was 60.9 ± 7.5%, with only 1.2% of superparasitized eggs. During individual acts of oviposition, we noted that F. arisanus possesses a highly flexible ovipositor that curves easily as it searches for additional suitable eggs, which may be of particular benefit when a female finds large clutches of eggs. The individual oviposition of F. arisanus in host fruits attacked by Anastrepha spp. varies with the egg clutch size of each fruit fly species: A. serpentina laid the biggest egg clutches (21.3 ± 1.4), followed by A. ludens (14.2 ± 0.9), and A. striata (1.0 ± 0.0) (=A. obliqua). The time spent by F. arisanus in individual ovipositions was parallel to these findings, reinforcing the idea that F. arisanus attacks several eggs in each individual insertion of its ovipositor. Neither formal oviposition acts, nor adult emergences of F. arisanus were registered in A. obliqua. We discuss the potential of F. arisanus as natural enemy of fruit flies of the genus Anastrepha, and explore the eventual developing of its mass rearing. Handling Editor: Torsten Meiners.     

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.     

Female pupae of the genetic sexing strain “Tap-7” of Anastrepha ludens as hosts of Coptera haywardi

Female black pupae from the Anastrepha ludens genetic sexing strain Tapachula-7 were evaluated as hosts for Coptera haywardi. We studied the host acceptance and the effects of age, irradiation and automated mechanical separation of black pupae on the emergence, survival, fecundity and flight ability of parasitoid C. haywardi adults. Our results indicated that black pupae are viable hosts for C. haywardi. Adult emergence was greater when the exposed pupae were three and five days old. The impact that occurred during mechanical separation reduced emergence by 16 %. The tested irradiation doses (25, 35 and 45 Gy) did not significantly affect adult emergence. No significant differences in longevity, fecundity or flight ability were observed between parasitoids that emerged from the Tapachula-7 black pupae and those that emerged from the standard mass-reared strain.     

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.     

Facultative polar extrusion of yolk masses and of hatching at the posterior egg pole in tephritid fruit flies (Diptera)

The eggs of Anastrepha fracterculus, A. sororcula, A. obliqua, A. serpentina and of Ceratitis capitata (Diptera : Tephritidae) show considerable morphological differences. Differences were also observed in the depth the eggs are inserted into the host fruits. In vivo inspection of the embryos of Anastrepha species showed that they may extrude polar masses of yolk before dorsal closure. In A.fracterculus and A. sororcula, 4 classes of embryos were found : (1) yolk masses at both ends; (2) masses only at the anterior end; (3) just a posterior mass and (4) embryos without any free mass. Only embryos of classes 3 and 4 were found in A. obliqua, while in A. serpentina, all the embryos extruded masses by the posterior end (class 3). There are variations in the frequencies of the classes as well as in the size of the extruded masses. Just before eclosion, the larvae of the Anastrepha species ingest the anterior mass of yolk (when present), turn round inside the egg, suck the posterior extruded mass, and eclose near the posterior-third of the eggs. No masses were present in samples of Ceratitis capitata embryos and the larvae do not present these complex behaviors and eclose near the anterior pole of the egg. The few previous studies on the embryology of other tephritid species did not report similar phenomena. The differences found among the species in relation to the phenomenon of yolk mass extrusion correlate, apparently, to the taxonomic relationship among them, as established before by genetic and morphologic parameters. Additional analyses of other species and genera are required to confirm if yolk mass extrusion is distinctive for the genus Anastrepha.     

Patterns of inner chorion structure in Anastrepha (Diptera: Tephritidae) eggs

The inner chorion structure of Anastrepha eggs from 16 species of various infrageneric taxonomic groups is described by scanning and transmission electron microscopy. The layers of the chorion, the outer egg membrane, are structurally similar. Furthermore, an additional trabecular layer (ATL) that exists in some species, together with other characteristics, facilitates the recognition of four patterns of chorion structuring: Pattern I, in which the ATL layer is absent, is found in Anastrepha amita, the Anastrepha fraterculus complex, Anastrepha obliqua, Anastrepha sororcula, Anastrepha suspensa and Anastrepha zenildae (fraterculus group), and Anastrepha bistrigata and Anastrepha striata (striata group); Pattern II in Anastrepha serpentina (serpentina group), Anastrepha grandis (grandis group) and Anastrepha pseudoparallela (pseudoparallela group), in which the ATL presents large open spaces with pillars; Pattern III, found in Anastrepha consobrina (pseudoparallela group), in which the ATL is composed of round cavities; and Pattern IV, found in Anastrepha alveata and Anastrepha pickeli (spatulata group), where the large ATL cavities are reticulated. Comparatively, the chorion structure in Anastrepha eggs is more complex than in eggs of other fruit flies, e.g., Bactrocera, Rhagoletis and Ceratitis.     

Quality assessment of Riptortus pedestris (Hemiptera: Alydidae) eggs cold-stored at different temperature and relative humidity regime

Supplementation of host resource can be more economical method for the biological control of insect pest compared to direct release of adult parasitoids. Periodical release of non-viable cold-stored eggs of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) has been found to enhance parasitism of this pest in soybean fields. To find the optimum environmental conditions for cold storage of these host eggs, we evaluated nine different combinations of temperature (2, 6, and 10 °C) and relative humidity (high 90–95%, medium 70–75%, and low 30–35%). After 30 d of cold-storage, eggs were weighed and held at 26.6 °C and 75% relative humidity for 8 d before testing. To test the eggs’ suitability as hosts following cold storage, females of Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) were released individually onto batches of eggs, and parasitization rates and the development, emergence, sex ratio, adult longevity, and size of parasitoid progeny were examined. Eggs stored at high relative humidity showed less weight loss than those stored at low relative humidity. The number of eggs parasitized was highest (5.9/15) on eggs stored at 6 °C and high relative humidity. Developmental times and adult emergence were optimal on host eggs stored at 2 °C and high relative humidity. A significantly lower proportion of eggs produced male parasitoids when eggs were stored at 2 or 6 °C. Adult longevity was not affected by egg storage conditions, but adult size of progeny decreased in eggs stored at 10 °C. In conclusion, eggs of R. pedestris stored below 6 °C and with a high relative humidity maintained the best quality for parasitization by O. nezarae.     

Behavioural plasticity in relation to egg and time limitation: the case of two fly species in the genus Anastrepha (Diptera: Tephritidae)

Reproductive opportunities in insects that deposit their eggs in discrete resource patches are frequently limited because the availability of oviposition substrates is often spatially and temporally restricted. Such environmental variability leads individuals to confront time‐ or egg‐limitation constraints. Additionally, species with different oviposition strategies (i.e. single egg layers vs clutch layers) commonly deal with different structural and ecological characteristics of larval host plants. To test the hypothesis that oviposition strategies such as laying eggs singly or in batches (clutches) are related to these constraints (i.e. egg vs time limitation), we compared the lifetime oviposition patterns of two closely related sympatric species of Anastrepha (Diptera: Tephritidae) with different oviposition strategies. We exposed five cohorts of A. obliqua and A. ludens females, over the course of their adult lifetimes, to three conditions of “habitat quality” (measured as host density per cage): unpredictable habitat quality (host density varied randomly from day to day between 1, 5, 15, 30 and 60 hosts/cage), low habitat quality (fixed density of one host/cage) and high habitat quality (fixed density of 60 hosts/cage).
Responses to host density conditions were strikingly different in the two species. (1) Frequency of host visits and oviposition events increased in A. obliqua but not in A. ludens when host densities increased. (2) Anastrepha ludens females accepted low quality hosts (i.e. fruits on which eggs had already been laid and were therefore partially covered with host marking pheromone) significantly more often than A. obliqua females did. (3) Females of A. obliqua adjusted their oviposition activity to variations in host density, whereas A. ludens females exhibited a constant oviposition pattern (i.e. did not respond to variations in host density). Based on the above, it is likely that in A. obliqua oviposition is governed by egg‐limitation and in A. ludens by time‐limitation constraints. We discuss the relationship between the oviposition strategies of each fly species and the fruiting phenology and density of their native host plants. We also address the possible influence of oogenesis modality and parasitism by braconid wasps in shaping oviposition behaviour in these insects.     

Host exploitation and contest behavior in a generalist parasitoid partially reflect quality of distinct host species

Information use determines parasitoid adaptive behavior in general, and host specialization or fitness in specific. Information regarding host suitability could affect sex allocation behavior, host exploitation, or aggressiveness in dyadic contests. In this paper, we relate aggressiveness of the pupal parasitoid Pachycrepoideus vindemmiae (Hymenoptera: Pteromalidae) with sex allocation and host exploitation when presented with different host species. More specifically, we presented parasitoids with puparia of five different Dipteran species: Drosophila melanogaster (Drosophilidae), Musca domestica (Muscidae), Anastrepha obliqua, Anastrepha fraterculus, and Ceratitis capitata (Tephritidae). Puparia of above species greatly varied in size and volume, were parasitized to differing extent and had varying fitness implications for P. vindemmiae. Using a composite measure of selected fitness currencies (i.e., parasitism level, offspring size, longevity and sex ratio), we typified D. melanogaster and A. obliqua as ‘low quality’ hosts for P. vindemmiae while puparia of C. capitata and A. fraterculus were considered of ‘high quality’. In contest dyads, female aggressiveness and host exploitation behavior differed between host species. Wasps exhibited highest frequencies of antennal striking and rival pursuit, and high degrees of puparium mounting, antennating and probing on C. capitata. Antennal striking frequency however was equally high on ‘low quality’ hosts such as D. melanogaster and A. obliqua. This work shows that a generalist parasitoid such as P. vindemmiae assesses host quality when confronted with hosts of differing species, size or nutritional suitability and employs such to define sex allocation, host exploitation, and contest behavior. However, contest and exploitation behavior only partially indicate host quality and broader parasitoid fitness implications. This work has further implications for parasitoid mass rearing and use of P. vindemmiae for biological control of Dipteran pests.     

Biological characteristics and thermal requirements of a Brazilian strain of the parasitoid Trichogramma pretiosum reared on eggs of Pseudoplusia includens and Anticarsia gemmatalis

A new strain of the parasitoid Trichogramma pretiosum, was collected in Rio Verde County, State of Goiás, Central Brazil, and designated as T. pretiosum RV. This strain was then found to be the most effective one among several different strains of T. pretiosum tested in a parasitoid selection assay. Therefore, its biological characteristics and thermal requirements were studied, aiming at allowing its multiplication under controlled environmental conditions in the laboratory. The parasitoid was reared on eggs of Pseudoplusia includens and Anticarsia gemmatalis at different constant temperatures within an 18–32 °C temperature range. The number of annual generations of the parasitoid was also estimated at those temperatures. Results have shown that T. pretiosum RV developmental time, from egg to adult, was influenced by all temperatures tested within the range, varying from 6.8 to 20.3 days and 6.0 to 17.0 days on eggs of P. includens and A. gemmatalis, respectively. The emergence of T. pretiosum RV from eggs of A. gemmatalis was higher than 94% at all temperatures tested. When this variable was evaluated on eggs of P. includens, however, the figures were higher than that within the 18–30 °C range (more than 98%), and were also statistically higher than the emergence observed at 32 °C (90.2%). The sex ratio of the parasitoids emerged from eggs of A. gemmatalis decreased from 0.55 to 0.29 at 18–32 °C, respectively. However, for those emerged from eggs of P. includens, the sex ratio was similar (0.73, 0.72 and 0.71) at 20, 28 and 32 °C, respectively. The lower temperature threshold (Tb) and thermal constant (K) were 10.65 °C and 151.25 degree-days when the parasitoid was reared on eggs of P. includens; and 11.64 °C and 127.60 degree-days when reared on eggs of A. gemmatalis. The number of generations per month increased from 1.45 to 4.23 and from 1.49 to 4.79 when the parasitoid was reared on eggs of P. includens and A. gemmatalis, respectively, following the increases in the temperature.     

Effect of Adult Nutrition on Male Sexual Performance in Four Neotropical Fruit Fly Species of the Genus Anastrepha (Diptera: Tephritidae)

Fruit flies (Diptera: Tephritidae) have been used previously as a model to explore the effect of nutrition on male reproduction. Here we tested the hypothesis that adult feeding history influences male sexual performance in four species of neotropical fruit flies of the genus Anastrepha (A. ludens, A. obliqua, A. serpentina, and A. striata), an approach that allowed us to consider species-specific ecological factors independent of phylogenetic constraints. We fed, from the moment of emergence, four experimental groups of males of each species with either (1) dry sucrose, (2) a mixture of dry sucrose and hydrolyzed protein (enzymatic yeast hydrolyzate), (3) a mixture of dry sucrose and bird feces, or (4) an open fruit [Citrus sinensis (orange), Mangifera indica (mango), Manilkara zapota (chico zapote), and Psidium guajava (guava) for A. ludens, A. obliqua, A. serpentina, and A. striata, respectively]. Cohorts of 12-day-old individuals (28 males [7 of each diet treatment] and 14 females) were released simultaneously into species-specific field cages and the following parameters recorded over a 4-day period (procedure repeated with five different cohorts for each species): number of males involved in calling activities every hour (i.e., pheromone emissions, wing fanning, wing motions, or extensions of the mouthparts), identity of copulating males, and copula duration. In the case of A. obliqua, we also observed separately cohorts of 20-day-old individuals. In A. obliqua, A. serpentina, and A. striata, males fed on a protein-supplemented diet had higher copulatory success when competing against males fed on other diets. Anastrepha serpentina and A. striata were sensitive to diet on all but two of the parameters analyzed (i.e., males with consecutive copulas and copula duration in the case of A. serpentina and males with multiple and consecutive copulas in the case of A. striata). In sharp contrast to this, the male mating performance of A. ludens was not affected by diet. Anastrepha obliqua was sensitive to different parameters depending on age. We discuss our findings and their sexual selection implications in light of each species' habits.     

Comparison of the thermal performance between a population of the olive fruit fly and its co-adapted parasitoids

Long-term separation of a host from its native parasitoids may result in divergent thermal adaptation between host and parasitoid. The olive fruit fly, Bactrocera oleae (Rossi), most likely originated from Sub-Saharan Africa, but has since had a long invasion history in cultivated olives that spans geographical barriers and continents. This study compared three major thermal performance profiles (development, survival, and reproduction) across a wide range of temperatures (10–34 °C) among a Californian population of the olive fruit fly and two African parasitoids, Psyttalia lounsburyi (Silvestri) and Psyttalia humilis (Silvestri), believed to have co-adapted with the fruit fly in its native range. Temperature ranges for the development and survival were 10–30 °C for the fly, 10–28 °C for P. lounsburyi, and 14–32 °C for P. humilis. There was no difference in any thermal performance measured between two P. humilis populations (Kenya and Namibia) tested. The most suitable temperature ranges for reproduction were 22–30 °C for the fly, 18–32 °C for P. humilis, and 18–26 °C for P. lounsburyi. The results showed slight differences in the thermal profiles among olive fruit fly and both parasitoids species, with P. humilis being more heat tolerant whereas P. lounsburyi was less heat tolerant than the fruit fly. The results are discussed with respect to thermal co-adaptation and classical biological control of the olive fruit fly.     

Differential thermal biology may explain the coexistence of Platygaster matsutama and Inostemma seoulis (Hymenoptera: Platygastridae) attacking Thecodiplosis japonensis (Diptera: Cecidomyiidae)

Two dominant parasitoids, Platygaster matsutama Yoshida and Inostemma seoulis Ko, often coexist in the host-parasitoid community of the pine needle gall midge, Thecodiplosis japonensis Uchida et Inouye. Subtle differences in parasitoid phenology appear to play a key role in reducing interspecific competition, but the specific thermal conditions for development of each species have not been defined. We examined the thermal biology of two sympatric parasitoids during postdiapause development at seven constant temperatures (12, 15, 18, 21, 24, 27, and 30 °C) to determine species-specific developmental parameters. The lower developmental threshold was estimated to be 4.2 °C and 8.4 °C, and the thermal constant was 741.2 and 946.1 degree days (DD) for P. matsutama and I. seoulis, respectively, using the linear model. The nonlinear model determined that the optimal temperature was 24.8 and 26.5 °C for P. matsutama and I. seoulis, respectively, but with an upper threshold temperature (30 °C) that was the same for both species. The development rate of P. matsutama was higher than that of I. seoulis over the entire thermal range, and the difference was highest at 21.5 °C. Despite the lower developmental rate, I. seoulis was more heat tolerant and its optimal temperature was closer to that of host insect than those of P. matsutama. The results showed clear differences in thermal biology between P. matsutama and I. seoulis. Potential implications are discussed with respect to coexistence of two parasitoids on a single host and biological control of T. japonensis.     

Efficacy of alkaline hydrolyzed torula yeast for monitoring Anastrepha spp.

Anastrepha fruit flies (Diptera: Tephritidae) are important pests of several crops in the Americas. Alkaline hydrolysis of proteins represents a potential source of novel attractants. Previous studies revealed a higher response by Anastrepha obliqua (Macquart) to alkaline hydrolyzed torula yeast compared with other attractants. Under field conditions, captures of Anastrepha fraterculus (Wiedemann), Anastrepha ludens (Loew), and Anastrepha serpentina (Wiedemann) were significantly higher in traps baited with alkaline hydrolyzed torula yeast than in traps baited with acid hydrolyzed protein (Captor) + borax. Fly attraction to alkaline hydrolyzed torula yeast varied with species but was higher in the 1st week and decreased after 2 or 3 weeks of use in the field. The release of ammonia gas from alkaline hydrolyzed torula yeast and CeraTrap was reduced after 3 weeks, but CeraTrap remained effective in the capture of flies whereas alkaline hydrolyzed torula yeast did not. No improvement in fly captures was observed for aged alkaline hydrolyzed torula yeast when 1% ammonium acetate was added to traps. The addition of propylene glycol or benzalkonium chloride did not improve trap captures over time. Although CeraTrap has advantages in attractiveness and durability, the attraction, simplicity, and low cost make alkaline hydrolyzed torula yeast a promising attractant when compared with the standard Captor + borax in short-term monitoring programs targeted at Anastrepha pests.     

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.     

Population dynamics of three Bactrocera spp. fruit flies (Diptera: Tephritidae) and two introduced natural enemies,Fopius arisanus (Sonan) and Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae), after an invasion by Bactrocera dorsalis (Hendel) in Tahiti

Oriental fruit fly, Bactrocera dorsalis (Hendel), invaded French Polynesia in 1996. In 2002 a natural enemy, Fopius arisanus (Sonan), was released and established. By 2009 mean (±SD) F. arisanus parasitism for fruit flies infesting Psidium guajava (common guava), Inocarpus fagifer (Polynesian chestnut) and Terminalia catappa (tropical almond) fruits on Tahiti Island was 64.8 ± 2.0%. A second parasitoid, Diachasmimorpha longicaudata (Ashmead), was released and established in 2008. Although widespread, parasitism rates have not been higher than 10%. From 2003 (parasitoid establishment) to 2009 (present survey) numbers of B. dorsalis, Bactrocera tryoni (Froggatt), Queensland fruit fly, and Bactrocera kirki (Froggatt) emerging (per kg of fruit) declined. For example, for P. guajava there was a decline of 92.3%, 96.8%, and 99.6%, respectively. Analysis of co-infestation patterns (1998–2009) of B. dorsalis, B. tryoni, and B. kirki, suggest B. dorsalis is now the most abundant species in many common host fruits. Establishment of F. arisanus is the most successful example of classical biological control of fruit flies in the Pacific outside of Hawaii and can be introduced if B. dorsalis spreads to other French Polynesian islands, as was the recent case when B. dorsalis spread to the Marquesas Islands. These studies support F. arisanus as a prime biological control candidate for introduction into South America and Africa where Bactrocera carambolae Drew and Hancock and Bactrocera invadens Drew, Tsuruta, and White, respectively, have become established.