New mariner elements in Anastrepha species (Diptera: Tephritidae)

Mariner-like elements (MLE) are members from class II of transposable elements also known as DNA transposons. These elements have a wide distribution among different groups of organisms, including insects, which can be explained by horizontal and vertical gene-transfer. MLE families have been described in tephritid flies and other genera. During screening for Wolbachia bacteria in fruit flies of the genus Anastrepha, we discovered two sequences related to mariner-like elements. Based on these sequences, we designed primers that allowed us to isolate and characterize two new mariner-like elements (Anmar1 and Anmar2) in Anastrepha flies. These elements, which belong to the mellifera and rosa subfamilies have a low nucleotide diversity, and are probably inactive and acquired by vertical transfer. This is the first report of mariner-like transposons in flies found in South America.     

Quantifying individual fruit fly consumption with Anastrepha suspensa (Diptera: Tephritidae)

We needed a technique to compare the consumption of baits by individual Carribbean fruit fly, Anastrepha suspensa (Loew). By improving consumption and determining individual dose, we could lower pesticide concentration while retaining bait/pesticide efficacy and potentially reduce the environmental impact of fruit fly bait/pesticide eradication methods. We report here a precise dye-based technique for the quantification of consumption by individual adult A. suspensa fruit flies. Fluorescein, measured at 491 nm, and cresol red, measured at 573 nm, were efficiently extracted with 0.1 M NaOH and quantified with a spectrophotometer. The lower limit for this method with 0.1% dye concentration is 300 nl consumed by an individual fly. Dye movement to the hindgut and possible defecation occurred in approximately 4 h; maximum ingestion occurred in approximately 1 h. Maximum experimental time is limited to 4 h. Flies preferred feeding upside down compared with right side up when given a choice; consumption was equal when flies were given no choice of feeding position. Thus, maximum bait/pesticide efficacy might be achieved with an upside-down presentation. Regurgitation led to a 100% overestimation of actual consumption with the J-tube presentation of food. Our individual fly consumption technique will be useful in comparing consumption in phagostimulant studies, estimating dose in oral toxicity tests, differentiating behavioral and physiological resistance in toxicant studies, ultimately leading to improved bait/pesticide methods and reduced environmental impact of area wide fruit fly eradication programs. This technique could be applied to studies of tephritid consumption, to the consumption of other insects, and to regurgitation studies.     

Patterns of resource distribution among conspecific larvae in two fruit fly species: Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae)

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Mating time of the West Indian fruit fly Anastrepha obliqua (Macquart) (Diptera: Tephritidae) under laboratory conditions

Allochronic reproductive isolation seems to be an important factor in speciation processes in Tephritidae since specific mating times are a widespread feature of its species. The timing of matings of the West Indian fruit fly, Anastrepha obliqua (Macquart) was investigated through group-focal observations, during ten days, under laboratory conditions. The number of observed matings and males exhibiting calling behavior varied significantly according to time of day. Sexual activities seemed to be concentrated in the afternoon period, with the male calling behavior reaching a peak between 3:30p.m. and 4:30p.m., and mating occurred most frequently from 2:00 p.m. to 4:30 p.m.     

Wolbachia endosymbiont in a species of the Anastrepha fraterculus complex (Diptera: Tephritidae)

Summary

In Anastrepha sp.2 aff. fraterculus, the egg-cell harbours a large population of endosymbionts. The bacteria were identified as belonging to genus Wolbachia by PCR assay using primers of the ftsZ gene followed by sequencing of the amplified band. Newly deposited eggs stained in toto by Hoechst show that the bacteria are unevenly dispersed throughout the egg-cell, with a higher accumulation at the posterior pole, and that the degree of infestation varies from egg to egg. Analysis by transmission electron microscopy shows that bacteria are present in the female germ line of embryonic and larval stages, as well as in the different cell types of the ovaries at the adult stage. Mature ova within the follicles harbour a large population of the symbionts. The results indicate the existence of a transovarian transmission of the endosymbionts in this fly.     

Wolbachia in Anastrepha Fruit Flies (Diptera: Tephritidae)

Endosymbiotic bacteria of the genus Wolbachia are widespread among arthropods and cause a variety of reproductive abnormalities, such as cytoplasmic incompatibility, thelytokous parthenogenesis, male-killing, and host feminization. In this study, we used three sets of Wolbachia-specific primers (16S rDNA, ftsZ, and wsp) in conjunction with the polymerase chain reaction (PCR), cloning and sequencing to study the infection of fruit flies (Anastrepha spp. and Ceratitis capitata) by Wolbachia. The flies were collected at several localities in Brazil and at Guayaquil, Ecuador. All of the fruit flies studied were infected with Wolbachia supergroup A, in agreement with the high prevalence of this group in South America. Phylogenetic analysis showed that the wsp gene was the most sensitive gene for studying the relationships among Wolbachia strains. The Wolbachia sequences detected in these fruit flies were similar to those such as wMel reported for other fruit flies. These results show that the infection of Anastrepha fruit flies by Wolbachia is much more widespread than previously thought.     

Revision of the fruit fly genus Capparimyia (Diptera, Tephritidae)

Capparimyia Bezzi is revised and eight species recognized, of which four are new: C. aenigma sp. nov., C. maerua sp. nov., C. mirabilis sp. nov., and C. spatulata sp. nov. A lectotype is designated for C. bipustulata (Bezzi, 1923), C. savastani (Martelli) and C. melanaspis (Bezzi). Capparimyia aristata nom. nov. is proposed as a replacement name for Pardalaspis (now Capparimyia ) bipustulata Bezzi, 1924 (preoccupied Bezzi, 1923). All species are described or re-described, with illustrations of mesonotal and wing patterns and male and female terminalia. A key to species is provided. Phylogenetic relationships within the genus are analysed cladistically and considered vis-à-vis the relationships between the host plants. Distribution patterns are discussed.     

Comparative analysis of microsatellite loci in four fruit fly species of the genus Ceratitis (Diptera: Tephritidae)

The possibility to cross-species amplify microsatellites in fruit flies of the genus Ceratitis was tested with the polymerase chain reaction (PCR) by analysing 23 Ceratitis capitata (Wiedemann) microsatellite markers on the genomic DNA of three other economically important, congeneric species: C. rosa (Karsch), C. fasciventris (Bezzi) and C. cosyra (Walker). Twenty-two primer pairs produced amplification products in at least one of the three species tested. The majority of the products were similar, if not identical in size to those expected in C. capitata. The structures of the repeat motifs and their flanking sequences were examined for a total of 79 alleles from the three species. Sequence analysis revealed the same repeat type as the homologous C. capitata microsatellites in the majority of the loci, suggesting their utility for population analysis across the species range. A total of seven loci were differentially present/absent in C. capitata, C. rosa, C. fasciventris and C. cosyra, suggesting that it may be possible to differentiate these four species using a simple sequence repeat-based PCR assay. It is proposed that medfly-based microsatellite markers could be utilized in the identification and tracing of the geographical origins of colonist pest populations of the four tested species and in the assessment of their risk and invasive potentials; thereby assisting regulatory authorities in implementing quarantine restrictions and other pest control measures.     

Intraspecific variation of cuticular hydrocarbon profiles in the Anastrepha fraterculus (Diptera: Tephritidae) species complex

The goal of this study was to define whether cuticular hydrocarbons (CHs) could be used for taxonomic determination of putative species hidden in the Anastrepha fraterculus cryptic species complex, widespread from Argentina to Mexico. Recently, increasing evidence of phenotypic and genetic variability has resulted in the characterization of eight morphotypes within this complex. The CH profiles of six A. fraterculus populations from Argentina, Brazil, Peru, Colombia and Mexico were analysed in this study by two‐dimensional gas chromatography coupled with mass spectrometry. In parallel, multiple factorial analyses were used to elucidate population structures. Vector populations segregated into four distinct groups. The analysis demonstrated that the studied populations from Peru, Argentina and southern Brazil (Vacaria) might be classified in accordance with the earlier division of the A. fraterculus complex into Peruvian, and Brazilian‐1 cryptic species, using the specific CH profiles. Population from south‐eastern Brazil (Piracicaba) formed separated group. Mexican and Andean (Colombian) putative species had similar CH signatures, when compared to each other.     

Consumption of sugars by Anastrepha suspensa (Diptera: Tephritidae)

We were interested in determining the feeding response of the Caribbean fruit fly, Anastrepha suspensa Loew (Diptera: Tephritidae), to various sugar concentrations to develop an improved bait for adults. We compared the consumption of 0.01-1.00 M concentrations of glucose, fructose, raffinose, and sucrose in no-choice tests for 24-h- and 6-d-old male and female flies. Sucrose was the most consumed sugar or within the most consumed group of sugars at 0.02-0.20 M concentrations. There were no differences in consumption among sugars at 0.01, 0.40, and 1.00 M. Consumption generally increased with increasing sugar concentration except that sucrose consumption peaked at 0.20 M. Twenty-four-hour females consumed less fructose than other sugars; 24-h males consumed more sucrose than fructose or raffinose, with an intermediate response to glucose. Females in the 6-d group consumed more sucrose than the other three sugars, whereas 6-d males exhibited no difference in consumption among sugars. In choice tests, flies consumed more sugar solution than water, but the difference between 0.20 M fructose and water was not significant for 24-h males or 24-h females. In choice tests between 0.20 M fructose and 0.20 M sucrose, both 24-h and 6-d females showed a preference for fructose. Males of both age classes showed no preference. These results indicate that the responses of flies to different sugars can vary by sugar, gender, and age.     

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.     

Sexual receptivity of Anastrepha obliqua (Diptera: Tephritidae) wild females affected by nutrition and egg load

The influence of feeding, egg load and stage of ovarian development on the sexual receptivity of some insect species has been reported. This work investigated the effects of different brewer's yeast concentrations in the diet offered to females of West Indian fruit fly, Anastrepha obliqua, on their sexual receptivity. Wild females were fed on artificial diets containing 2.0 g brewer's yeast per 100 mL of water (low‐yeast diet, LY diet), 6.5 g yeast per 100 mL of water (high‐yeast diet, HY diet) or only sucrose (Su diet) and then placed with the males. Female sexual receptivity tests were carried out in acrylic boxes in the laboratory under controlled conditions (temperature, humidity and light). Females fed on the HY diet were more sexually receptive to male courtship than the other females. Additionally, when fed on the same diet (HY diet), those females with higher egg load were more sexually receptive. The data suggest that the ingestion of a protein source is essential for increasing sexual receptivity and that egg load is the most important factor affecting sexual receptivity of A. obliqua females.     

Reproductive behaviour of the South American fruit fly Anastrepha fraterculus (Diptera: Tephritidae): laboratory and field studies

Abstract. The mate choice, courtship and oviposition behaviour of laboratory-reared and field-collected Anastrepha fraterculus (Wied.) were compared. In laboratory cultures in Southampton the duration of male calling activity in small leks increased gradually from 1-2h at 5 days old to up to 7 h at 10 days. This finding correlates with previous reports on the time at which male salivary glands, which are believed to produce sex pheromone, are fully developed. Wild flies which emerged from infested fruits in Brazil began to oviposit on the day they mated, whereas in laboratory flies oviposition began 1 day following the first mating. Both types of fly usually defended their position on a particular fruit throughout the day, and re-mated with either virgin or mated males. There was no significant difference in mating duration. Females did not copulate before the mean age (±SE) of 16.8±0.9 days. For both types of flies mating initiation occurred in the first 2h of photophase, with virgin females choosing mainly mated males. The average number of matings in the laboratory was three for females and four for males, and the interval between matings in females was significantly increased after the second mating. It is suggested that the tendency of virgin females to mate with mated males will lead to increased fitness, as males are on average 48 days old at their second mating. The potential life span of around 200 days for both sexes would allow adults to bridge the gap between seasonally available fruits in warm-temperate and sub-tropical South America.     

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.     

Calling behavior of mass-reared and wild Anastrepha serpentina (Diptera: Tephritidae)

The calling behavior of mass-reared and wild males of Anastrepha serpentina (Wiedemann) (Diptera: Tephritidae) was studied both in the laboratory and in field cage tests. In the laboratory, density (1, 5, and 10 males per container), age, and hour of day significantly affected calling behavior. Mass-reared males called independently of density, whereas wild males only called at densities of 5 and 10 individuals. Males of both strains started calling when they were 5-7 d old. The daily pattern of male calling was similar in both strains, starting at 0730 hours, and reaching a peak at 1330-1630 hours. Field cage tests showed that mass-reared males started calling when they were 5d old; the period of peak calling was when males were 8-9 d old. In contrast, wild males began calling when they were 10 d old, reaching peaks when males were 13, 15, and 18 d old. Wild males tended to form leks to call during each day of the experiment, whereas mass-reared males only formed leks during 2 d, both strains displaying very low levels. During field cage tests, males, independently of strain, displayed two calling peaks, one peak in the morning and one peak in the afternoon, whereas males observed in the laboratory only showed a single calling peak. The results are discussed in view of the effects of mass rearing A. serpentina males in relation to potential use of the sterile insect technique.     

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.     

The genus Anastrepha (Diptera; Tephritidae) in the principal fruits of Costa Rica and its reduction to human pseudomyiasis

Three species of Anastrepha are usually found independently in 9 fruits from different regions of Costa Rica. A striata was found in 5, and A. serpentina and A. obliqua in each of 3 different fruits. During the harvest season, these larvae frequently produce intestinal pseudomyiasis, especially in children.     

Thermal death kinetics of egg and third instar Mediterranean fruit fly (Diptera: Tephritidae)

Two developmental stages of Ceratitis capitata (Wiedemann), 24-h-old eggs and third instars, 8 d after oviposition, were subjected to thermal exposures in a heating block system, at various temperatures of 46, 48, 50, and 52 degrees C to determine the thermal death kinetics of the insects. At these temperatures, 100% mortality was achieved by exposure of 300 C. capitata larvae for 60, 15, 4, and 1 min, respectively. The 0.5 order kinetic model had the best fit to the survival ratio for all the treatment temperatures, hence it was used for the prediction of the lethal times. The thermal death time (TDT) curves showed that the third instars were more heat-resistant than eggs, especially at the two low temperatures (46 and 48 degrees C). Under temperature-time combinations that did not result in complete kill, the thermal mortality for eggs was also significantly higher than that for third instars. The activation energy values calculated from the TDT curves were 490.6 and 551.9 kJ/mol, respectively, for thermal death of eggs and third instars.