Beatriz Aguiar Jordão Paranhos

Pheromone Analyses of the Anastrepha fraterculus (Diptera: Tephritidae) Cryptic Species Complex

ABSTRACT The South American fruit fly Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) cryptic species complex is presently one of the most studied pest models in terms of speciation and population mating compatibility. The improvement of pest-control techniques has strongly relied on successful implementation of laboratory strains into wild populations. Pheromone communication plays an important role in the mating process in the South American fruit fly. Therefore, the main goal of the present study was to investigate the pheromone composition of 7 different populations, originating from geographically distant locations in Brazil and Argentina. Fourteen volatile compounds were identified in calling male emanations by GC×GC/TOF-MS and the data obtained were subsequently analyzed by multivariate statistics. The pheromone composition varied both quantitatively and qualitatively among the studied populations. These results will serve as the basis for further electrophysiological analyses.

Field Dispersal and Survival of Sterile Medfly Males Aromatically Treated with Ginger Root Oil

ABSTRACT We studied the dispersal behavior and survival of sterile medfly males either treated or not with ginger root oil (GRO), in field conditions, in Petrolina-PE, northeast Brazil, from May 2006 to December 2007 in a sterile insect technique (SIT) program. The tsl strain Vienna 8 from the Ceratitis capitata Wied. (Diptera: Tephritidae), medfly, mass-rearing facility located in Juazeiro-BA, Brazil, was used. The results showed that sterile males either exposed or not to GRO exhibit similar dispersal behavior and postrelease survival. More than 60% of the sterile males, either treated or not treared wth GRO, were recovered at a 25-m distance from the releasing point, ≈20% at 50 m, and 5% in traps situated 100 m from the releasing point. Around 90% of the sterile males, exposed or not to GRO, were recovered 5 d after release of the sterile male individuals, whereas <1% were recovered after 11 d. Our results imply that ginger root oil can be used to treat sterile medfly males without interfering with their dispersal or survival in the field.

A Compound Produced by Fruigivorous Tephritidae (Diptera) Larvae Promotes Oviposition Behavior by the Biological Control Agent Diachasmimorpha longicaudata (Hymenoptera: Braconidae)

ABSTRACT Tephritid fruit fly parasitoids use fruit-derived chemical cues and the vibrations that result from larval movements to locate hosts sequestered inside fruit. However, compounds produced by the larvae themselves have not been previously described nor their significance to parasitoid foraging determined. We collected the volatiles from four species of tropical and subtropical Tephritidae: Anastrepha suspensa (Loew), Bactrocera dorsalis Hendel, Bactrocera cucurbitae Coquillett, and Ceratitis capitata (Wiedemann), representing two subfamilies (Dacinae and Trypetinae). Paraethylacetophenone, an analog of a known tephritid parasitoid attractant, was a major constituent of all four, and was not associated with larvae of another acalypterate fly, Drosophila melanogaster Meigen, or with the calypterate Musca domestica L. It also was present in volatiles from whole, A. suspensa infested fruits of Eugenia uniflora (L.). Para-ethylacetophenone was not necessarily produced as a direct consequence of fruit consumption because it also was detected from larvae that developed in two artificial diets and in spent diets subsequent to larval development. Sensillae on both the antennae and ovipositor of the opiine braconid fruit fly parasitoid, Diachasmimorpha longicaudata (Ashmead) responded to the para-ethylacetophenone in larval volatiles and as a synthetic. Although a potential cue to foraging parasitoids, para-ethylacetophenone showed no long range (>1m) attractiveness to the adult female parasitoid, but did stimulate ovipositor-insertion and oviposition into both a natural (fruit) and an artificial (parafilm) substrate. Thus it may prove useful in colonizing and mass-rearing opine fruit fly parasitoids.

Mass-rearing of Mediterranean fruit fly using low-cost yeast products produced in Brazil

Ceratitis capitata is one of the most important pests of fruits for exportation, and Sterile Insect Technique (SIT) has been the most efficient and environmental friendly technique used to control fruit fly populations around the world. A key goal in achieving a successful SIT program is a mass rearing system producing high quality insects at low cost. Providing adults with an artificial diet containing hydrolysed protein has been the major obstacle for bio-production facilities in Brazil, because it is expensive and has to be imported. Two other commercial products, autolysed yeast (AY) and yeast extract (YE), of domestic origin and low cost, were tested as substitutes of the imported hydrolyzed protein. To compare their efficiency we observed the female fecundity, adult survival and egg viability of flies raised on diets containing one of each of the different protein products. Flies reared on the domestic yeast products had equivalent or superior performance to the flies reared on imported protein. Both AY and YE can be a possible substitute for imported hydrolyzed protein for C. capitata mass-rearing, as they are cheaper and are readily available in the national market.

Intrinsic Competition and Competitor-Free-Space Influence the Coexistence of Parasitoids (Hymenoptera: Braconidae: Opiinae) of Neotropical Tephritidae (Diptera)

ABSTRACT Endoparasitoid larvae may eliminate heterospecific competitors by physical or physiological means. The outcomes of these intrinsic competitions are often predictable with one species typically eliminating the other. The opiine braconids Doryctobracon areolatus (Szepligeti) and Utetes anastrephae (Viereck) are among the most common native parasitoids of frugivorous Tephritidae in the Neotropics and subtropics. U. anastrephae is typically the victor in intrinsic interactions with D. areolatus, but the later has a longer ovipositor and may find a competitor-free-space in larger fruit whose hosts are beyond the reach of U. anastrephae. An Asian opiine species, Diachasmimorpha longicaudata (Ashmead) has been introduced throughout much of the Americas. Its ovipositor is longer than that of D. areolatus and if it is a superior intrinsic competitor it should be able to cause local extinctions of D. areolatus. The outcomes of sequential ovipositions by D. longicaudata and D. areolatus and U. anastrephae found that D. longicaudata significantly suppresses development of D. areolatus. However, competitions between D. longicaudata and U. anastrephae were more equal. The denial of competitor free space may account for the gradual replacement of D. areolatus by D. longicaudata in Florida where both species were introduced ≈40 yr ago. Diachasmimorpha longicaudata and D. areolatus continue to coexist in Mexico and this could be because of greater abiotic and biotic environmental complexity that allows for separate niches. Establishment or augmentative releases of D. longicaudata could result in elimination of native parasitoids and this should be considered before its introduction.

Dispersion patterns of Diachasmimorpha longicaudata (Hymenoptera: Braconidae) in citrus orchards in southeast Brazil

Abstract We studied the dispersion patterns of the exotic endoparasitoid, Diachasmimorpha longicaudata (Ahsmed) (Hymenoptera: Braconidae), in 1999 (summer) and in 2000 (winter) in a citrus orchard in southeast Brazil. Different population densities of D. longicaudata were released in the centre of the orchard, and their dispersion was determined by using yellow, sticky, rectangular traps, placed in various distances and heights around the release point. Our results suggest that during summer, climatic conditions did not affect dispersion. However, in winter, dispersion rates were positively affected by temperature, and negatively by rainfall. Both estimated dispersal distance and surface were higher in summer than in winter for all release densities. Dispersion peaked at 2000 parasitoids ha−1 in summer and 8000 parasitoids ha−1 in winter. The importance of our results for the biological control of fruit flies by augmented or innoculative releases of D. longicaudata in southeast Brazil is discussed.

Current knowledge of the species complex Anastrepha fraterculus (Diptera, Tephritidae) in Brazil

Abstract The study of the species complex Anastrepha fraterculus (Af complex) in Brazil is especially important in a taxonomical, evolutionary and pest management context, because there are evidences that some of them may occur in sympatry. In this review, we analyzed the main results supporting evidences that three cryptic species occur in Brazil. The taxonomical and phylogenetic relationships based on eggshell morphology, adult morphometrics, as well as cytotaxonomy and genetic differentiations are discussed. We also review available information on sexual behavior including acoustic communication of males during courtship and sexual incompatibility; and chemical signals involved in the communication between sexes, with a special focus on sex pheromones. We examined the role of long- and short-range pheromones (male-produced volatiles and cuticular hydrocarbons, respectively), their implications in sexual isolation, and their possible use for chemotaxonomic differentiation of the putative species of the Af complex.

Exposure of sterile Mediterranean fruit fly (Diptera: Tephritidae) males to ginger root oil reduces female remating

Females of Ceratitis capitata are facultative polyandrous, with remating more common in laboratory strains rather than wild ones. In the application of the Sterile Insect Technique (SIT) against this pest, large overflooding ratios of sterile : wild males can increase the remating frequency. Females that mate for the first time with a sterile male tend to remate more frequently. The exposure of sterile males to ginger root oil (GRO) is used in C. capitata SIT programmes to increase the sterile male mating success. Exposing males to an ‘aromatherapy’ with GRO may also increase the remating frequency among wild females. The frequency of wild females remating, number of matings per female, the refractory period between the first and second mating, and the duration of the first and second matings of wild females were determined under laboratory conditions for three mating scenarios that included wild males only or wild males competing with sterile males (either GRO‐treated or non‐treated). Wild females first mated with sterile males exposed to GRO had their remating rate over the following 6 days and the mean number of matings per female reduced in comparison to those first mated with non‐exposed sterile males, from 62.5% to 32.2% and from 3.1 to 1.6 respectively. The remating parameters of females mated with sterile GRO‐exposed males resembled those of females mated with wild males.

Offspring in Response to Parental Female Densities in the Fruit Fly Parasitoid DIACHASMIMORPHA LONGICAUDATA (Hymenoptera: Braconidae: Opiinae)

Abstract As part of an evaluation of the braconid parasitoid Diachasmimorpha longicaudata (Ashmead) as a biocontrol agent of Ceratitis capitata (Wiedemann) in Brazil, the aims in the current study were to find the best parental ratio of females to males in the rearing cages in order to get the highest female biased offspring in the parasitoid rearing process, and to verify the parasitism efficiency on C. capitata according to parental female densities. Three treatments were assessed: T1 (20 females: 20 males), T2 (60 females: 20 males) and T3 (100 females: 20 males). Ten late-third instars of C. capitata were offered daily to each female parasitoid from the 1st to the 12th d of age. The parental female productivity, fecundity, offspring sex ratio, percentage of parasitoid emergence, and daily mortality of parental females and males at different female/male densities were evaluated. The results indicated that numbers higher than 20 parental females did not affect offspring sex ratio, overall offspring production, nor the percent parasitism. Female biased offspring occurred in all three parental female/male ratios analyzed in this study, except that predominately males developed from parasitoid eggs laid in the age interval 1-2 d post emergence. Higher parasitoid female productivity and fecundity were found at the 1:1 female/male per cage density whereas lower productivity and fecundity were recorded at the 5:1 female/male ratio. Higher female/male ratio in the parental cages increased the mortality rate of females but did not influence the number of parental male deaths. The results may facilitate advancement of an optimum mass-rearing system to aid in control of C. capitata in Brazil.

Optimum dose of ginger root oil to treat sterile Mediterranean fruit fly males (Diptera: Tephritidae)

The sterile insect technique (SIT) is widely used as part of an integrated approach to reduce field populations of the Mediterranean fruit fly (Ceratitis capitata, Diptera: Tephritidae). Aromatherapy based on exposure to ginger root oil (GRO) volatiles is known as a method to significantly improve the sexual performance of sterile medfly males, and is being used in many mass‐rearing facilities around the world. However, the optimum dose of GRO is not well defined. This work evaluated in laboratory cages four different doses of GRO and a control (0, 0.1, 0.25, 0.5 and 0.75 ml/m3), and two different methods to hold flies prior to release (paper bags and plastic cages). The objective was to find the lowest dose that provides optimal improvement in mating performance of sterile males when competing with wild males for wild females and optimal reduction in fertility of wild females. Egg hatch, copula duration, the Relative Sterility Index (RSI), and a Competitiveness (C) value (based on RSI) were calculated for each treatment to assess male sexual performance and induction of sterility. The method used to hold flies did not influence the aromatherapy effect. The mean time spent by wild females in copula with wild males was significantly longer than with sterile males for all treatments, except when sterile males were treated with 0.1 ml of GRO/m3. Amongst all doses studied, it is recommended to apply the lowest dose, 0.1 ml of GRO/m3, since at this dose both the RSI and induced sterility reached the highest levels, and were not statistically different from the 0.25 and 0.5 GRO/m3 doses. Indeed, this dose showed a very significant improvement in the mating competitiveness of sterile males aromatically treated with GRO.