Biology and fertility life table of Bactrocera carambolae on grape and acerola

Bactrocera carambolae Drew & Hancock (Diptera: Tephritidae), native of Southeast Asia, is present in Brazil but restricted to Amapá, Pará and Roraima, where it has quarantine pest status. The possible dispersion to other fruit producing regions of Brazil could cause damages, including for exportation, due to quarantine restrictions imposed by fruit importing countries. The objective of this work was to describe the biological parameters and calculate the fertility life table of B. carambolae on grape (Vitis vinifera L.) and acerola (Malpighia emarginata DC.). The experiment was conducted in the laboratory under controlled conditions. The mean number of punctures and the mean number of eggs per female on grapes were 1.48 ± 0.05 and 9.87 ± 0.36, respectively. The mean number puparia per fruit was 0.1 ± 0.02 (grape) and 0.5 ± 0.10 (acerola). The pupal viability was 82.4% (grape) and 70.6% (acerola). The mean time ± SE of one generation, in days, was 25.8 ± 1.10 (grape) and 19.7 ± 0.21 (acerola). The mean fecundity was 1663.8 ± 501.01 (grape) and 206.9 ± 26.21 (acerola) with eggs viability of 5.6% (grape) and 12.5% (acerola). The mean longevity, in days, was 77.3 ± 12.13 on grape and 82.4 ± 4.24 on acerola. The study found that B. carambolae completes its biological cycle on grape and on acerola leaving offspring.     

Preference and performance of Diachasmimorpha kraussii (Fullaway) (Hymenoptera: Braconidae) on five commercial fruit species

Diachasmimorpha kraussii is a polyphagous endoparasitoid of dacine fruit flies. The fruit fly hosts of D. krausii, in turn, attack a wide range of fruits and vegetables. The role that fruits play in host selection behaviour of D. kraussii has not been previously investigated. This study examines fruit preference of D. kraussii through a laboratory choice‐test trial and field fruit sampling. In the laboratory trial, oviposition preference and offspring performance measures (sex ratio, developmental time, body length, hind tibial length) of D. kraussii were investigated with respect to five fruit species [Psidium guajava L. (guava), Prunis persica L. (peach), Malus domestica Borkh. (apple), Pyrus communis L. (pear) and Citrus sinensis L. (orange)], and two fruit fly species (Bactrocera jarvisi and B. tryoni). Diachasmimorpha kraussii responded to infested fruit of all fruit types in both choice and no‐choice tests, but showed stronger preference for guava and peach in the choice tests irrespective of the species of fly larvae within the fruit. The wasp did not respond to uninfested fruit. The offspring performance measures differed in a non‐consistent fashion between the fruit types, but generally wasp offspring performed better in guava, peach and orange. The offspring sex ratio, except for one fruit/fly combination (B. jarvisi in apple), was always female biased. The combined results suggest that of the five fruits tested, guava and peach are the best fruit substrates for D. krausii. Field sampling indicated a non‐random use of available, fruit fly infested fruit by D. kraussii. Fruit fly maggots within two fruit species, Plachonia careya and Terminalia cattappa, had disproportionately higher levels of D. krausii parasitism than would be expected based on the proportion of different infested fruit species sampled, or levels of fruit fly infestation within those fruit.     

Field superparasitism by Diachasmimorpha longicaudata attacking Anastrepha spp. larvae on mango fruits

The incidence of superparasitism in field populations of Diachasmimorpha longicaudata (Ashmead), a solitary larval–pupal endoparasitoid, attacking Anastrepha fruit fly species was determined. From 14,550 fruit fly larvae infesting mango fruits in the field, 68.9% (10,038) survived to the pupal stage. Of these pupae, 3780 (37.7%) were parasitized, of which 2075 (54.9%) were superparasitized. The number of oviposition scars per pupa ranged between 1 and 29, although high numbers were rare. The presence of one or two scars per host was frequent, but only 8.6% of pupae had more than three scars. Fruit size was positively related to the level of infestation by Anastrepha spp. and was significantly correlated with the numbers of parasitized and superparasitized pupae by D. longicaudata. The length and width of host pupae were positively related to superparasitism, and superparasitism was positively correlated with a sex ratio biased toward females. Our data show that superparasitism is present in natural populations of D. longicaudata at remarkable rates and confers some advantageous features such as a female-biased sex ratio. These findings favor the election of this species as a viable biocontrol agent for augmentative releases because the favorable proportion of adult females emerging from superparasitized pupa should contribute to better pest control.     

First record of Anastrepha bahiensis Lima (Diptera: Tephritidae) infesting fruits of Averrhoa carambola L. in the eastern Amazon,Brazil

We report for the first time field infestation under natural conditions by Anastrepha bahiensis on star fruit (Averrhoa carambola L., Oxalidaceae) in the state of Pará, Eastern Amazon, Brazil. This report reinforces the importance of field infestation studies on fruit flies in the Brazilian Amazon.     

蝇蛹俑小蜂对寄主及果实的趋性反应

【背景】蝇蛹俑小蜂是实蝇类害虫蛹期重要的寄生蜂之一。有关植物果实和寄主挥发物在蝇蛹俑小蜂寻找寄主过程中的作用尚不明确。【方法】采用"Y"型嗅觉仪测试了寄主和果实(健康果实和虫害诱导果实)对蝇蛹俑小蜂的引诱作用。【结果】虫伤1 d的番石榴和杨桃果实对蝇蛹佣小蜂雌蜂具有显著的引诱作用;寄主蛹——3日龄橘小实蝇蛹和4日龄瓜实蝇蛹对蝇蛹俑小蜂雌蜂也具有显著的引诱作用。蝇蛹俑小蜂雌蜂对雄蜂有显著的吸引作用。橘小实蝇性诱剂甲基丁香酚对蝇蛹俑小蜂的搜索行为则无显著影响。【结论与意义】寄主蛹和幼虫危害1 d的果实能释放对蝇蛹俑小蜂有引诱作用的物质,这可为利用蝇蛹俑小蜂防治实蝇类害虫提供基础信息。     

Development of a genetic sexing strain in <Emphasis Type="Italic">Bactrocera carambolae</Emphasis> (Diptera: Tephritidae) by introgression of sex sorting components from <Emphasis Type="Italic">B. dorsalis</Emphasis>, Salaya1 strain

Background

The carambola fruit fly, Bactrocera carambolae Drew & Hancock is a high profile key pest that is widely distributed in the southwestern ASEAN region. In addition, it has trans-continentally invaded Suriname, where it has been expanding east and southward since 1975. This fruit fly belongs to Bactrocera dorsalis species complex. The development and application of a genetic sexing strain (Salaya1) of B. dorsalis sensu stricto (s.s.) (Hendel) for the sterile insect technique (SIT) has improved the fruit fly control. However, matings between B. dorsalis s.s. and B. carambolae are incompatible, which hinder the application of the Salaya1 strain to control the carambola fruit fly. To solve this problem, we introduced genetic sexing components from the Salaya1 strain into the B. carambolae genome by interspecific hybridization.

Results

Morphological characteristics, mating competitiveness, male pheromone profiles, and genetic relationships revealed consistencies that helped to distinguish Salaya1 and B. carambolae strains. A Y-autosome translocation linking the dominant wild-type allele of white pupae gene and a free autosome carrying a recessive white pupae homologue from the Salaya1 strain were introgressed into the gene pool of B. carambolae. A panel of Y-pseudo-linked microsatellite loci of the Salaya1 strain served as markers for the introgression experiments. This resulted in a newly derived genetic sexing strain called Salaya5, with morphological characteristics corresponding to B. carambolae. The rectal gland pheromone profile of Salaya5 males also contained a distinctive component of B. carambolae. Microsatellite DNA analyses confirmed the close genetic relationships between the Salaya5 strain and wild B. carambolae populations. Further experiments showed that the sterile males of Salaya5 can compete with wild males for mating with wild females in field cage conditions.

Conclusions

Introgression of sex sorting components from the Salaya1 strain to a closely related B. carambolae strain generated a new genetic sexing strain, Salaya5. Morphology-based taxonomic characteristics, distinctive pheromone components, microsatellite DNA markers, genetic relationships, and mating competitiveness provided parental baseline data and validation tools for the new strain. The Salaya5 strain shows a close similarity with those features in the wild B. carambolae strain. In addition, mating competitiveness tests suggested that Salaya5 has a potential to be used in B. carambolae SIT programs based on male-only releases.

     

Effect of emergence time on the reproductive parameters of mass-reared Anastrepha ludens (Diptera: Tephritidae) flies

In the mass rearing of fruit flies, the adult emergence time is gradual, due to factors such as variation in food consumption in the larval phase, the female oviposition behavior and environmental conditions, among others. Here, we investigate the effect of emergence time on sex ratio, fecundity, fertility, body size and mating performance in mass-reared Anastrepha ludens (Diptera: Tephritidae) flies. The results of the study indicated that the emergence of the flies is gradual and lasts approximately 96?h, but the highest proportion of emerged flies was observed at 48?h. The flies emerging at 24 and 48?h showed higher fecundity than those emerging at 72 and 96?h, but there were no significant differences in the sex ratio, fertility and male mating performance. Body size was significant, the flies that emerged at 24, 48 and 72?h were bigger than those emerged at 96?h. The discussion focuses on the effect of emergence time on the rearing processes and release of the Mexican fruit fly.     

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.     

Tolerance and antibiosis resistance to cabbage root fly in vegetable Brassica species

Four accessions of the wild species Brassica fruticulosa Cyrillo (Brassicaceae) were studied in order to identify its tolerance and antibiosis resistance to the cabbage root fly, Delia radicum L. (Diptera: Anthomyiidae), in comparison to a widely cultivated cauliflower cultivar and a rapid cycling Brassica oleracea L. line. Antibiosis was prominent, as the insects reared on resistant accessions showed reduced individual pupal weight, total pupal weight, adult dry weight, and the longest average fly eclosion time. Host plant resistance, however, did not affect the sex ratio of adult flies. A study of the root architecture of plants with and without root fly inoculation revealed differences in the structure within B. oleracea accessions. A long main root and a high number of lateral roots appeared to be important characteristics for a Brassica type, with a higher tolerance level to cabbage root fly attack.     

Effect of plant oils on quality parameters of Bactrocera tryoni (Froggatt) reared on liquid larval diet

Liquid larval diets have been developed for several tephritid fruit flies including Queensland fruit fly, Bactrocera tryoni (Frogatt) (Q‐fly). In liquid diets, wheat germ oil (WGO) is usually added to improve performance in some quality parameters of reared flies, especially flight ability. However, for some flies, other plant oils may be more readily available, cheaper or produce flies of superior performance. In the present study, four alternative types of plant oils – rice bran, canola, vegetable, and sesame – were incorporated into a fruit fly liquid larval diet to replace the currently used wheat germ oil and their efficacy on the quality parameters of reared Q‐fly was compared to diets containing wheat germ oil or no oil. The quality parameters included: total pupal yield (N), pupal recovery (%), larval duration (days), pupal weight (mg), adult emergence (%), adult fliers (%), rate of fliers (%), sex ratio (%), F₁ egg/female/day and egg hatching (%). There were significant differences among treatments in performance of Q‐fly. Vegetable oil appeared better in terms of total pupal yield, percentage of pupal recovery, percentage of adult emergence, percentage of fliers, mean egg/female/day and % F₁ egg hatch compared with other oil treatments, especially from that of WGO treated diet. The result suggests that WGO can be substituted with rice bran and vegetable oil to improve the liquid larval diet for rearing of B. tryoni, with vegetable oil being the best replacement.     

Effect of larval density and host species on preimaginal development of Bactrocera tau (Diptera: Tephritidae)

The fruit fly, Bactrocera tau (Walker) (Diptera: Tephritidae), is an important pest of fruit and vegetable crops. In this study, host preference of B. tau females and the effects of host species and larval density on larval survival, pupal weight, adult emergence, and developmental duration were investigated on cucumber (Cucumis sativus L.), sponge gourd (Luffa cylindrical L. (Roem)), bitter gourd [Momordica charantia (Cucurbitaceae) L.], guava [Psidium guajava (Myrtaceae) L.], and tangerine [Citrus reticulata (Rutaceae) (Blanco)]. The results showed that females preferred to cucumber over other host species. Larval feeding experience affected subsequent host oviposition preference of adult females. Host species and initial larval density affected certain aspects of the biology of B. tau. Larval density negatively affected insect performance. Survival rates at low densities were significantly higher than that at high densities. Total developmental duration reduced at high larval densities. Cucumber was more suitable to larval growth. Larvae on cucumber grew faster and the puparia were heavier than that on other host species. Larval survival, pupation rate and adult emergence were higher on cucumber compared with those in other host species. Oviposition preference of adult females was correlated with performance of their offspring.     

桔小实蝇和番石榴实蝇对6种寄主果实的产卵选择适应性

植食性昆虫对寄主植物的选择适应性是研究昆虫和植物协同进化关系的核心内容之一。评估寄主植物对植食性昆虫种群的适合度,需要综合分析昆虫对寄主的产卵选择性和寄主对昆虫的取食适合性。以桔小实蝇和番石榴实蝇为研究对象,分别测定了这两种实蝇对6种寄主果实:番石榴、香蕉、杨桃、木瓜、甜橙、番茄的产卵选择性以及幼虫取食后对其生长发育的影响。寄主产卵选择性实验分别采用完整寄主果实直接供试产卵和块状寄主果实气味引诱产卵两种处理方式;在生长发育适应性实验中,以幼虫和蛹的存活和生长发育等相关参数作为评价指标。实验结果表明,寄主的供试方式不同,两种实蝇的选择性均有明显差异;对寄主气味选择性强的寄主更适合于两种实蝇后代的生长发育。两种实蝇对6种寄主果实的产卵选择性和后代发育适合性两者相关性不显著,与许多文献报道单一地采用发育适合性(如发育历期、存活率或蛹重等)作为评价寄主选择性的结果不一致。两种实蝇之间对6种寄主果实的产卵选择和幼虫取食适合性既具相似性也具差异性,表明这两种实蝇在寄主生态位上既有重叠性又有分化性。     

Effects of fruit fly host, fruit species, and host egg to female parasitoid ratio on the laboratory rearing of Biosteres arisanus

The host suitability of the oriental fruit fly, Bactrocera dorsalis (Hendel), for development of Biosteres arisanus (Sonan), a braconid parasitoid, was compared with three other fruit fly species, namely, Mediterranean fruit fly, Ceratitis capitata Weidemann, melon fly, Bactrocera cucurbitae Coquilett, and Malaysian fruit fly, Bactrocera latifrons (Hendel). In addition, effects of five different fruit species, namely, Carica papaya L. (solo papaya), Musa sapientum (L.) O. Ktze. (apple banana), Mangifera indica (L.) (Haden mango), Terminalia catappa (L.) (false kamani), and Citrus aurantiifolia (Christman) Swingle (common lime), on the parasitization rate of B. dorsalis and sex ratio of parasitoid progenies were evaluated. Effects of host egg to female B. arisanus ratios on parasitoid progeny yields were likewise determined. The host suitability of fruit flies for development of B. arisanus was ranked as: B. dorsalis>C. capitata=B. latifrons=B. cucurbitae. Based on percent parasitization of B. dorsalis, preference of B. arisanus females for host eggs varied with fruit species, however, preferential oviposition displayed by female parasitoids did not influence sex ratios of subsequent parasitoid progenies. Increases in host egg to female parasitoid ratios of 5:1, 10:1, 20:1, 25:1, and 30:1 corresponded with increases in parasitoid progeny yield reaching a plateau at 20:1.     

Is a mango just a mango? Testing within-fruit oviposition site choice and larval performance of a highly polyphagous fruit fly

For fruit flies, fully ripe fruit is preferred for adult oviposition and is superior for offspring performance over unripe or ripening fruit. Because not all parts of a single fruit ripen simultaneously, the opportunity exists for adult fruit flies to selectively choose riper parts of a fruit for oviposition and such selection, if it occurs, could positively influence offspring performance. Such fine scale host variation is rarely considered in fruit fly ecology, however, especially for polyphagous species which are, by definition, considered to be generalist host users. Here we study the adult oviposition preference/larval performance relationship of the Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), a highly polyphagous pest species, at the “within-fruit” level to see if such a host use pattern occurs. We recorded the number of oviposition attempts that female flies made into three fruit portions (top, middle and bottom), and larval behavior and development within different fruit portions for ripening (color change) and fully-ripe mango, Mangifera indica L. (Anacardiaceae). Results indicate that female B. dorsalis do not oviposit uniformly across a mango fruit, but lay most often in the top (i.e., stalk end) of fruit and least in the bottom portion, regardless of ripening stage. There was no evidence of larval feeding site preference or performance (development time, pupal weight, percent pupation) being influenced by fruit portion, within or across the fruit ripening stages. There was, however, a very significant effect on adult emergence rate from pupae, with adult emergence rate from pupae from the bottom of ripening mango being approximately only 50% of the adult emergence rate from the top of ripening fruit, or from both the top and bottom of fully-ripe fruit. Differences in mechanical (firmness) and chemical (total soluble solids, titratable acidity, total non-structural carbohydrates) traits between different fruit portions were correlated with adult fruit utilisation. Our results support a positive adult preference/offspring performance relationship at within-fruit level for B. dorsalis. The fine level of host discrimination exhibited by B. dorsalis is at odds with the general perception that, as a polyphagous herbivore, the fly should show very little discrimination in its host use behavior.     

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.     

Effect of <Emphasis Type="Italic">Fopius arisanus</Emphasis> oviposition experience on parasitization of <Emphasis Type="Italic">Bactrocera dorsalis</Emphasis>

Fopius arisanus (Sonan) (Hymenoptera: Braconidae) is an important fruit fly parasitoid, successfully introduced in programs of classical biological control around the world. One aspect of its reproductive biology that has received increasing attention is the role of learning on parasitization by individual females. In this study, we examined the effect of previous oviposition opportunities on the reproductive success and progeny sex ratio of F. arisanus on eggs of Bactrocera dorsalis Hendel (Diptera: Tephritidae). Our results indicate that the proportion of eggs parasitized and parasitoid yield both increase with increasing experience, as acquired by individual females via previous oviposition opportunities. These effects are shown to be unrelated to parasitoid age out to three weeks, which we found not to have an effect on parasitization, yield, or sex ratio. We discuss the implications of our results on mass rearing and also in terms of the efficiency of this biological control agent in the field.     

Effect of food deprivation on attractiveness of food sources, containing natural and artificial sugar and protein, to three African fruit flies: Ceratitis cosyra, Ceratitis fasciventris, and Ceratitis capitata

The effects of food deprivation, age, and mating status on the responses of three fruit fly species, Ceratitis cosyra (Walker), Ceratitits fasciventris (Bezzi), and Ceratitits capitata (Wiedemann) (Diptera: Tephritidae) to natural and artificial sugar and protein food sources were investigated. Natural food sources included guava [Psidium guajava L. (Myrtaceae)] juice (a common host fruit for all three fruit fly species) and bird faeces (farm chicken). Artificial food sources included molasses (obtained from a local sugar factory) and a locally produced protein bait (the International Centre of Insect Physiology and Ecology yeast). In all species studied, sugar deprivation of immature (1–2‐day‐old) male and female flies increased their response to food odours, although it did not change their preference for the type of odour (protein or sugar). Protein deprivation of mature (14–17‐day‐old) male and female flies also increased their response to food odours compared to protein‐fed flies. Protein‐deprived females were highly attracted to odours from protein sources in particular. Odours from natural food sources, guava juice, and chicken faeces, were more attractive to food‐deprived flies than were odours from artificial sugar and protein sources. Attraction to food odours increased significantly with increasing age for protein‐deprived females of all species. For males and females of all species, nutritional state was a more important factor than mating status in influencing responses of flies to food odours. Practical implications of these findings are discussed in terms of strategies for fruit fly control using food baits.     

Host status of ‘Scifresh’ apples to the invasive fruit fly species Bactrocera dorsalis,Zeugodacus cucurbitae,and Ceratitis capitata (Diptera: Tephritidae)

We conducted no-choice cage and field infestation studies to determine if the fruit of apples (Malus x domestica L., ‘Scifresh’) are hosts for three invasive tephritid fruit fly species that may enter New Zealand or other apple growing areas. In screen cage tests, punctured and unpunctured (intact) fruit of ‘Scifresh’ apples were exposed to gravid females of Bactrocera dorsalis (Hendel) (Oriental fruit fly), Zeugodacus (Bactrocera) cucurbitae (Coquillet) (melon fly), or Ceratitis capitata (Wiedemann) (Mediterranean fruit fly), outdoors for 24 h and then held on sand in the laboratory for four weeks for pupal development and adult emergence. Unpunctured fruit produced an average of 269.4, 4.3 and 70.1 puparia per kg of fruit for B. dorsalis, Z. cucurbitae and C. capitata, respectively. Punctured fruit produced an average of 619.4, 0.8 and 129.5 puparia per kg of fruit for B. dorsalis, Z. cucurbitae and C. capitata, respectively. By comparison, unpunctured and punctured papaya fruit (Carica papaya, ‘Rainbow’, a preferred host) produced 206–675 and 464–735 puparia per kg of fruit, respectively, across all species. In general, the average weight of individual fruit fly puparia from apple was significantly less (41–71%) than that of puparia reared from papaya, and development times were slower on apple than on papaya. Overall, ‘Scifresh’ apples were a moderately good host for B. dorsalis and C. capitata, and a very poor host for Z. cucurbitae in cage tests. Field exposure of ‘Scifresh’ apples suspended from papaya trees resulted in no infestation by B. dorsalis or Z. cucurbitae under natural conditions. This information will help to inform decisions about quarantine restrictions and potential crop loss in the event of incursions of these fruit flies into apple-producing countries.     

Grapefruit as a host for the West Indian fruit fly (Diptera: Tephritidae)

The most common hosts for the West Indian fruit fly, Anastrepha obliqua (Macquart) (Diptera: Tephritidae) are fruit in the family Anacardiaceae (mango [Mangifera L.] and mombin [Spondias L.] species). However, similar to many of the tropical fruit flies of major economic importance, this species attacks several other families of crop fruit, including Annonaceae (cherimoya, Annona cherimola Mill.), Myrtaceae (guava, Psidium L.), Oxalidaceae (carambola, Averrhoa carambola L.), Passifloraceae (granadilla, Passiflora quadrangularis Mill.), and Sapotaceae [mamey sapote, Pouteria sapota (Jacq.) H. E. Moore & Steam]. In the family Rutaceae the economically important genus Citrus has been reported and until recently considered a host for this fruit fly. In this study, we reviewed the taxonomy of A. obliqua, tested specific chemicals that may inhibit oviposition, compared egg-to-adult survival of A. obliqua on preferred hosts and on grapefruit (Citrus X paradisi Macfad.), and measured fruit tissue-specific developmental rates of A. obliqua and the known citrus breeding Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae), from egg to pupae. Our literature review shows much confusion concerning the taxonomy of this and related Anastrepha species, including synonymies and confusion with other species. The deterrent effect of the highest concentration of flavonoids for oviposition, although significant, was not absolute. Experiments carried out under laboratory conditions showed 15-40 times greater survival of A. ludens (whose preferred hosts include Rutaceae) on grapefruit compared with A. obliqua for both tree attached and harvested fruit. Experiments of survival of developing stages over time showed that the two species oviposit into different tissues in the fruit, and mortality is much higher for the West Indian fruit fly in the flavedo and albedo of the fruit compared with the Mexican fruit fly.     

Variations in carambola infestation rates byBactrocera carambolae drew and hancock (Diptera: Tephritidae) with fruit availability in a carambola orchard

The relationship between the infestation rate of carambola fruits byBactrocera carambolae Drew and Hancock was investigated in a carambola orchard. Phenology of the fruits was found to influence percentage infestation of fruits byB. carambolae. The proportion of unbagged or susceptible fruits infested varied with time of year and tended to decrease with the increase of unbagged fruits available on the tree. The number of ovipunctures per fruit varied with fruit size and was also found to be indicative of the number of adult insects (B. carambolae and parasitoids) that will emerge from each fruit. Higher number of susceptible fruits available on each tree also decreased both the number of ovipunctures per fruit and the number of eggs laid per fruit, which could possibly be due to the strategy of spreading the risk adopted by the femaleB. carambolae or a result of random selection with more hosts available. The main parasitoids recorded wereBiosteres vandenboschi (Fullaway) andB. arisanus (Sonan). The mean percentage of parasitism was 38.3% and it followed roughly that of infestation of fruits.