The Tephritidae family comprises agriculturally important insect pests that cause significant economic losses worldwide. Interest in eco-friendly pest control methods is growing, and novel strategies involving symbiotic microorganisms are under investigation. Strategies involving the bacterium Wolbachia have been proposed for managing pest insects and disease vectors. However, they have not yet been used for tephritid pest control. The aim of this study was to detect and characterize Wolbachia strains in tephritid flies from Argentina that could be proposed for use in area-wide programs applying the incompatible insect technique. We also aimed to identify and analyze Wolbachia strains in little-studied species of no economic importance. Infested fruits were collected from different localities in two provinces of Argentina. Adults were identified and the presence of Wolbachia strains was evaluated using the wsp surface protein primer. Genotyping was performed through multilocus sequence typing (MLST). When multiple infections were suspected, the obtained amplification products were cloned into P-GEN. Two new Wolbachia hosts were identified, Rhagoletis blanchardi Aczél and Rhagoletotrypeta pastranai Aczél from Tucumán. Interestingly, we found a multiple infection by Wolbachia in R. pastranai, detecting three different strains. The Anastrepha fraterculus (Wiedemann) strains were similar to haplotypes previously described in Argentina. Our results provide the first records of Wolbachia strains in new tephritid hosts from Argentina. The phenotypic effects of these strains on their hosts should be further investigated to evaluate their potential for Wolbachia-based control strategies.

Ceratitis capitata (Diptera: Tephritidae) is a highly polyphagous species and a seriously pest with a significant economic importance, having a great number of studies focused in its management. Recently, there has been a surge of interest in the symbiotic relationship between gut bacteria and their insect hosts. In this context, the objective of this work was to evaluate the role of gut microbiota on symbiotic and aposymbiotic wild medfly adult sexual behaviour, especially on mate choice and mating success. We also evaluate latency and mating time, sperm transference, testes and ovarian sizes and female fecundity. Finally, we compared cuticular hydrocarbon profiles to explore other possible mechanisms that mediate medfly mating success. For this purpose, teneral wild medfly adults were separated into two groups, symbiotic and aposymbiotic. Aposymbiotic adults were treated with an antibiotic mixture (tetracycline plus ciprofloxacin) until sexual maturity. Results of sexual behaviour assays showed that symbiotic males were more successful in mating in comparison with aposymbiotic males, and female preference could be related with a greater sexual organ development of symbiotic females and differences in male hydrocarbon cuticular profiles. Results support the hypothesis that the presence of gut bacteria can play a beneficial role on the sexual behaviour. Knowledge about the importance of cuticular hydrocarbons acting in mating recognition was obtained. This work is the first to report the influence of gut microbiota on this component of the exoskeleton for wild medfly and might be useful for the improvement of sustainable strategies for pest management such as the sterile insect technique.

BACKGROUND:Maize (Zea mays L.) is the most widely cultivated cereal in the world. The introduction of the Bt gene and the development of sweet corn varieties with softer pericarp has led to the emergence of new pests in the genus Euxesta (Diptera: Ulidiidae), previously considered as secondary invaders. In Argentina, Euxesta eluta and Euxesta mazorca predominate. Some control measures are being implemented; however, no biorational control strategies have been developed to date. With aims at developing effective monitoring traps, this study investigated visual and olfactory stimuli that attract Euxesta sp. RESULTS:Three experiments were conducted in the laboratory and the field: (i) on visual stimuli; color, tonality, shape, size, and contrast. Mature flies were attracted to blue, rectangular, large traps. Contrast did not have an effect on capture. (ii) Olfactory stimuli: intact ears and ears with lepidopteran damage were compared in a two-way stationary olfactometer. There was a higher offspring yield from damaged than intact ears. (iii) Field response to baits was evaluated: Plustrap, torula yeast, hydrolyzed protein with borax, and spinosad. Traps with hydrolyzed protein with borax captured the highest number, followed by traps with torula yeast. For these two baits, the number of females captured was higher than males. E. eluta was more abundant than E. mazorca. CONCLUSION:This study provides key information for the development of monitoring tools for Euxesta sp., highlighting the importance of visual and olfactory stimuli in capture. Implementing traps based on these findings can be used for management in maize. © 2025 Society of Chemical Industry.

Ceratitis capitata (Wiedemann) is a cosmopolitan pest of economic importance. It is controlled by using the Sterile Insect Technique (SIT), which involves rearing and release of sterile males destined to mate with wild females, causing generation‐to‐generation suppression. Medflies are colonized by microorganisms, primarily the Enterobacteriaceae, with the genera Klebsiella and Enterobacter being the most common. Such microbiota contributes to host fitness. During the SIT, diet with antibiotics and irradiation for sterility of adults alter microbiota. We aimed to determine the role of Medfly microbiota on resistance to abiotic stress conditions, evaluating its function under: (i) starvation, (ii) elevated temperatures, and (iii) dry environments. These conditions simulate challenges Medfly may encounter after release, which differ from controlled rearing environments. We compared adult survival between symbiotic and aposymbiotic individuals, under starvation, two thermal regimes (25 and 30 °C) or two humidity regimes (20%–25% and 80%–90% R.H.). Aposymbiotic individuals were obtained after providing them with water containing a mixture of antibiotics and methylparaben. Treatment with antimicrobials effectively reduced the gut microbiota. While starvation had no significant effect on survival, a higher proportion of aposymbiotic individuals died earlier at 30 °C and under dry humidity, with the effect being more pronounced after 48 h. Our results suggest that microbiota plays a role in adaptation of Medfly under environmental stress. We report for the presence of a culturable yeast in the digestive tract of C. capitata , Zygosaccharomyces rouxii . Providing a probiotic adult diet with bacteria and Z. rouxii prior to release could improve SIT outcomes under adverse conditions.

Among phytophagous insects, life history often evolves as a strategy to cope with seasonality in host plant availability. Whereas specialization often leads to dormancy, aestivation, or longevity, polyphagous species bridge between periods of host availability by exploiting alternative host plants. The aim of the present work was to characterize the life histories of four species of specialist and generalist uni- and multivoltine frugivorous fruit flies - Ceratitis capitata Wiedemann, Anastrepha fraterculus Wiedemann, Rhagoletis blanchardi Aczel, and Rhagoletotrypeta pastranai Aczel (all Diptera: Tephritidae) - inhabiting in sympatry in Las Yungas phytogeographical province in Tucum & aacute;n (northwestern Argentina). For this purpose, infested host plant fruits were sequentially collected during two consecutive years, and flies recovered from these fruits were subjected to demographic experiments to establish longevity and overwintering mechanisms. The results indicated that life cycles were tightly related to host fruit availability, where multivoltine species sequentially exploit different host plants over the year, whereas univoltine species must undergo pupal dormancy to reach the next host fructification period and may extend the duration of dormancy when climatic conditions are acyclic and unpredictable. The present study may broaden knowledge about diapausing Tephritidae in subtropical regions and may contribute to an increased conceptual basis for the improvement of pest control strategies, such as the sterile insect technique (SIT).

Solanaceae is a large plant family whose center of diversity is in South America, it includes important crop plants and various weeds. Several species of Tephritid fruit flies have been reported in association with Solanaceous plants, particularly those in the genus Rhagoletis. However, many of these reports are on commercial crops such as tomato, and there is still little knowledge on use of wild native plants. Here, we report results of a 3-year survey of Solanaceous fruit in North-Western Argentina. Fruit of 22 species of Solanaceae were collected over 3 years in the Yungas, Dry Chaco, and Monte biomes. Fourteen of these plants were infested with dipteran, coleopteran, and lepidopteran larvae. Lycium sp. represents a new host plant record for Haywardina cuculi, Solanum aligerum is a new host plant record for Anastrepha fraterculus, Drosophila suzukii, and Rhagoletis blanchardi. Solanum argenteum, Solanum confusum, Solanum delitescens, Solanum pseudocapsicum, Solanum stukertii, and Solanum tenuispinum are new host plant records for Rhagoletis blanchardi. Solanum trichoneuron is a new host plant record for Anastrepha fraterculus. Two unidentified species of Lonchaeidae were found infesting nine species of Solanaceae. Hymenopteran parasitoids in the genus Utetes, Doryctobracon, and Ganaspis were found in association with Solanaceae infesting tephritids. We also report notes on the life cycle and behavior of the tephritids recovered during this sampling effort.

Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males. However, distinguishing between male sperm competition and active female sperm choice is difficult for species with internal fertilization. Nevertheless, species that store and use sperm of different males in different storing structures and species where females are able to expel all or part of the ejaculates after copulation may be able to bias fertilization. We report a series of experiments aimed at providing evidence of female sperm choice in Euxesta eluta (Hendel), a species of ulidiid fly that expels and consumes ejaculates after copulation. We found no evidence of greater reproductive success for females mated singly, multiply with the same male, or mated multiply with different males. Female E. eluta possesses two spherical spermathecae and a bursa copulatrix for sperm storage, with a ventral receptacle. There was no significant difference in storing more sperm in spermathecae 24 h after copulation than immediately after copulation. Females mated with protein-fed males had greater reproductive success than similar females mated to protein-deprived males. Protein-fed females prevented to consume the ejaculate, retained more sperm when mated to protein-fed males than when mated to protein-deprived males. Our results suggest that female E. eluta can exert control of sperm retention of higher quality males through ejaculate ejection.

Ceratitis capitata is the most serious agricultural pest in Argentinean fruit-growing regions. The use of baited traps for Medfly control is an expanding and increasingly successful integrated management strategy. The high cost of traps and attractants is one of the main limitations for use on either a massive scale or a small-scale control. This study aimed to evaluate the advantages or disadvantages of using natural fruit juice-based lures for Medfly adult monitoring at the orchard level in an irrigated valley. Medfly capture with a standard protein attractant was compared with peach, apple, sweet orange, fig, and grape juices. All attractants were evaluated in 1.5-liter disposable plastic bottles that served as traps. The most relevant finding was the interaction between attractant effectiveness and season. While the standard yeast was the most effective attractant during summer, the highest Medfly caught values recorded during both spring and autumn were achieved with traps baited with orange juice. The use of fruit juices as attractants and disposable bottles as traps can decrease the impact on non-target insects and reduce management costs.

Tephritid fruit flies in the genus Rhagoletis bridge between predictable periods of fruit availability by becoming dormant. To cope with acyclic unpredictable events (e.g., frost, mast seeding, etc), a proportion of the population can undergo prolonged dormancy. In the case of walnut infesting Rhagoletis, host plant-derived cues such as juglone soil concentration vary seasonally in predictable patterns. Here, we examined the effects of host plant parts and derived compounds on emergence rates and dormancy duration of Rhagoletis completa (Cresson), Rhagoletis zoqui (Bush) (Diptera: Tephritidae), and associated parasitoids. Pupae of both species were exposed to walnut leaves, fruit, or fruit and leaves and compared to a control. In a second experiment, R. zoqui were exposed to 10 mg l-1 of juglone applied to pupation medium during four consecutive 4-week time periods under variable combinations of temperature and frequency of exposure. Overall, the presence of fruit resulted in greater overwintering survival of R. completa but had no effect on the duration of dormancy of either fly species. Application of juglone over two consecutive periods produced greater mortality of R. zoqui than the control. Three parasitoid species emerged from R. completa and one from R. zoqui. Duration of dormancy for parasitoids was longer than that of fly hosts. Regardless of treatment, 13.3-18.4% of R. completa pupae and 1.3-2.8% R. zoqui engaged in prolonged (>year) dormancy. Our results indicate that host plant derived cues have little or no effect on survival and duration of dormancy of walnut infesting Rhagoletis, and at the tested concentration juglone is toxic to R. zoqui pupae. Testing the effect of juglone at lower concentrations is necessary to rule out its role as an environmental cue for regulation of dormancy. So far, host plant fruiting phenology appears to play a greater role than host plant derived cues in selecting for fly eclosion times.

The figitid Ganaspis pelleranoi and the braconid Doryctobracon areolatus (Hym: Braconidae, Opiinae) are wide-ranging (from Florida, USA to Argentina) fruit fly parasitoids with tropical and subtropical distribution with a wet and temperate climate. In Argentina, both parasitoid species are thought to be restricted to the subtropical rainforests of the northwest and northeast, locally known as 'Yungas' and 'Paranaense' forests, respectively. However, these species recently have been recorded at the Monte and Thistle of the Prepuna eco-region, an arid region of central-western Argentina. Despite the extreme environmental conditions, anthropic artificial irrigation seems to be playing a fundamental role in fostering the presence and persistence of these species. Maximum Entropy (MaxEnt) models were developed to assess the suitability of these areas to harbor both species. The present work is a first approach to identify suitable areas for the distribution of these two fruit fly biological control agents in the American continent; based on 19 bioclimatic variables. Furthermore, the models resulting from including the new records in the 'Monte' eco-region suggest that local populations may become adapted to particular micro-environmental conditions generated by artificial irrigation. Models revealed that these artificial oases are suitable for G. pelleranoi but seem to be unsuitable for D. areolatus. This first and new approach to the area suitability of these species invites to produce models that reflect actual distribution including more records of presence in oases with similar conditions, thus decreasing the bias of the model generated by over reliance on areas with higher humidity (forest), which correspond to the distribution known before the inclusion of the new records.

Development of cost-effective traps and attractants is important for sustainable pest management. In the case of the Medfly, Ceratitis capitata Wiedemann, a worldwide pest of fruit production, recent interest in development of mass trapping strategies and low-cost easy-to-get artisanal traps for resource poor grower use has prompted renewed interest in research on attractants and traps. Additionally, such interest is also rooted on the need for effective female attractants to monitor wild population dynamics under male-only sterile fly releases. Response of wild flies and sterile males to makeshift traps (modified polyethylene terephthalate (pet) bottles) baited with fruit juice and wine vinegar dilutions with and without the addition of sugar revealed that a 50% dilution of wine vinegar or sweetened orange juice were more attractive than the standard Torula baits during the offseason (after harvest) in a peach orchard in arid irrigated valleys of San Juan Argentina. Such results suggest that volatiles from orange peel and juice are good candidates for development of Medfly attractants, and that pet bottles baited with sweetened orange juice and wine vinegar may be used by small growers and homeowners as low-cost-effective traps for Medfly control. Our results also suggest that Medfly response to food-based and fruit-based volatiles may be seasonally dynamic, a finding with important pest management implications.

Endosymbiont-induced cytoplasmic incompatibility (CI) may play an important role in arthropod speciation. However, whether CI consistently becomes associated or coupled with other host-related forms of reproductive isolation (RI) to impede the transfer of endosymbionts between hybridizing populations and further the divergence process remains an open question. Here, we show that varying degrees of pre- and postmating RI exist among allopatric populations of two interbreeding cherry-infesting tephritid fruit flies (Rhagoletis cingulata and R. indifferens) across North America. These flies display allochronic and sexual isolation among populations, as well as unidirectional reductions in egg hatch in hybrid crosses involving southwestern USA males. All populations are infected by a Wolbachia strain, wCin2, whereas a second strain, wCin3, only co-infects flies from the southwest USA and Mexico. Strain wCin3 is associated with a unique mitochondrial DNA haplotype and unidirectional postmating RI, implicating the strain as the cause of CI. When coupled with nonendosymbiont RI barriers, we estimate the strength of CI associated with wCin3 would not prevent the strain from introgressing from infected southwestern to uninfected populations elsewhere in the USA if populations were to come into secondary contact and hybridize. In contrast, cytoplasmic-nuclear coupling may impede the transfer of wCin3 if Mexican and USA populations were to come into contact. We discuss our results in the context of the general paucity of examples demonstrating stable Wolbachia hybrid zones and whether the spread of Wolbachia among taxa can be constrained in natural hybrid zones long enough for the endosymbiont to participate in speciation.

Episodes of isolation and secondary contact among populations of insects of Nearctic origin during Pleistocene glacial/postglacial climatic cycles had a strong evolutionary influence on the diversity of flies in the genus Rhagoletis in mountainous areas of Mexico. As a series of experiments undertaken to gather support for phylogenetic hypotheses on the origin of three walnut-infesting species in the suavis group, we examined pre- and postzygotic isolation between Rhagoletis completa Cresson, 1929 and R. ramosae Hernández-Ortiz, 1985. Despite morphological, biological, and behavioral differences, these two species were found to be capable of hybridization. Mating experiments in large enclosures revealed asymmetric sexual isolation. There were notable differences in male sexual behavior. While R. ramosae males mated exclusively on host fruit, R. completa males used fruit and alternative mating locations. During fruit-guarding and male-male contests, R. completa and R. ramosae males adopted markedly different wing postures. R. completa females were more reluctant to copulate with heterospecific males than R. ramosae females. During no choice crosses in small enclosures, there was a reduction of egg hatch for the hybrid cross of R. completa males × R. ramosae females. Our results and previous studies on reproductive isolation between other species pairs in the suavis group support a clade in which R. ramosae, R. zoqui Bush, 1966, and R. completa are close relatives all still capable of hybridizing.

Abstract An important criterion for understanding speciation is the geographic context of population divergence. Three major modes of allopatric, parapatric, and sympatric speciation define the extent of spatial overlap and gene flow between diverging populations. However, mixed modes of speciation are also possible, whereby populations experience periods of allopatry, parapatry, and/or sympatry at different times as they diverge. Here, we report clinal patterns of variation for 21 nuclear‐encoded microsatellites and a wing spot phenotype for cherry‐infesting Rhagoletis (Diptera: Tephritidae) across North America consistent with these flies having initially diverged in parapatry followed by a period of allopatric differentiation in the early Holocene. However, mitochondrial DNA (mtDNA) displays a different pattern; cherry flies at the ends of the clines in the eastern USA and Pacific Northwest share identical haplotypes, while centrally located populations in the southwestern USA and Mexico possess a different haplotype. We hypothesize that the mitochondrial difference could be due to lineage sorting but more likely reflects a selective sweep of a favorable mtDNA variant or the spread of an endosymbiont. The estimated divergence time for mtDNA suggests possible past allopatry, secondary contact, and subsequent isolation between USA and Mexican fly populations initiated before the Wisconsin glaciation. Thus, the current genetics of cherry flies may involve different mixed modes of divergence occurring in different portions of the fly's range. We discuss the need for additional DNA sequencing and quantification of prezygotic and postzygotic reproductive isolation to verify the multiple mixed‐mode hypothesis for cherry flies and draw parallels from other systems to assess the generality that speciation may commonly involve complex biogeographies of varying combinations of allopatric, parapatric, and sympatric divergence.

Abstract Promiscuous mating systems are widely distributed among animals and can be promoted by operational sex ratios (number of receptive adults; OSR). In populations where OSR is not biased towards any sex, the possibility that males and females mate with several individuals increases. For both sexes to synchronize in time and space for reproduction, adults should possess or simultaneously acquire nutrients required to reach sexual maturity. Among synovigenic (without a full complement of eggs at eclosion) species, nutrient acquisition, protein in particular, may influence the OSR. In the Agave fly Euxesta bilimeki (Hendel) (Diptera: Ulidiidae), both sexes engage in multiple mating and females frequently expel all or part of the ejaculate. Here, we assessed the effect of protein intake on gonadic development, and estimated OSR from field-collected individuals. Body protein content was compared between wild and laboratory individuals with access to different diets, and mating frequency and individual mating rate were analyzed for cohorts at a 1:1 sex ratio. Both sexes required protein ingestion for gonadic development, but there were no differences in protein content between field-collected males and males fed protein and sugar in the laboratory, despite the fact that males assigned 9.3% of their corporal weight to testicles. Euxesta bilimeki is a promiscuous species where both males and females mate multiply with one or several individuals in short periods of time; thus, large testes size may be linked to the need of voluminous ejaculate production, and might be further exacerbated by female ejaculate expulsion.

Abstract With the purpose of broadening knowledge on the evolution of life history strategies and behaviour of fruit flies within the tribe Carpomyini, the natural history and mating behaviour of the poorly known species Rhagoletotrypeta pastranai Aczél, are described for the first time. Larvae of R. pastranai were recovered from infested Celtis tala Gillies ex Planch and Celtis iguanaea (Jacq.) Sarg. during a 2-month fruiting period. Adults emerged from the recovered pupae after an average of 144.9 ± 3.9 days for females and 143.2 ± 3.38 days for males, suggesting that most individuals became dormant. Results of a variable winter length study suggested that environmental factors other than winter length may regulate dormancy/diapause duration in this subtropical species. Under laboratory conditions, R. pastranai adults lived an average of 51.13 ± 3.06 days in case of females and 48.08 ± 3.76 days in case of males, and required 5–15 days to reach sexual maturity. Behavioural observations under confinement revealed scarce sexual activity but sufficed to determine that, as in other members of the tribe Carpomyini, R. pastranai exhibits a male resource defence mating system. We discuss our findings emphasizing the importance of documenting the natural history and behaviour of unknown species of family Tephritidae and additionally, we highlight the necessity of future research to understand factors regulating dormancy/diapause and the evolution of life history strategies and sexual behaviour of subtropical species.

Plant-derived compounds can be an environmentally friendly alternative to synthetic pesticide use for pest management. Essential oils (EOs) in several plant families have been found to be toxic to various pest species of insects through topical application, ingestion, and as fumigants. Previous studies revealed that, among various environmentally friendly insecticides, the EOs of Baccharis dracunculifolia and Pinus elliottii and an ethanol extract of Solanum granulosoleprosum plus Ricinus communis, were toxic to Ceratitis capitata and Anastrepha fraterculus (Diptera: Tephritidae) when applied topically to pupae or when ingested by adults. Here, we aimed to examine the potentially toxic effects of these plant-derived compounds when these two pestiferous fruit fly species were exposed to their vapors. We also examined their fumigant effect on female fecundity and fertility and compared it with water and ethanol controls. Exposure of C. capitata and A. fraterculus sexually mature adults to volatiles and vapors of both B. dracunculifolia and P. elliottii EOs resulted in lower longevity (half-life), survivorship, and female fecundity than the water vapor control. Toxicity of C. capitata was greater for P. elliottii than for B. dracunculifolia while the reverse was true for A. fraterculus. Exposure to vapors of S. granulosoleprosum + R. communis (S + R) had no effect on longevity but reduced survivorship of adults of both species. Interestingly, exposure to vapors of S + R, 50% (v/v) and pure ethanol resulted in greater fecundity of females of both frugivorous fly species than the water control. By contrast, fertility (% egg hatch) was in all cases high (>85%) and not different than the water control. Exposure to ethanol vapors appears to have similar effects on frugivorous tephritids as those reported on saprophagous and frugivorous species of Drosophila, a novel finding that may have important practical implications.

The Mediterranean fruit fly Ceratitis capitata is a globally invasive pest, often controlled with the sterile insect technique (SIT). For the SIT, mass-rearing of the target insect followed by irradiation are imperatives. Sterile males are often less able to inhibit female remating and transfer less number of sperm, and even irradiation could affect male reproductive organs, with consequences for their ability to inhibit female remating. On the other hand, male age could affect their ability to modulate female response after mating. Here, we evaluated the quality of the genetic sexing strain Vienna-8-tsl mass-reared in Bioplanta San Juan, Argentina, under laboratory conditions, with regard to: (i) the ability of sterile males irradiated at 100 or 140 Gy to inhibit female remating, in the same day and at 24 h of first copulation; (ii) the ability of 3, 4 or 5 day-old sterile males to inhibit female remating at 24 h of first copulation, and (iii) the effect of a reduction in irradiation doses on the number of sperm stored by females and reproductive organ size in virgin males. Sterile males were better able than wild males to inhibit female remating in the same day of first copulation and as able as wild males 1 day after first copulation. Male age did not affect their ability to inhibit female receptivity. Number of sperm stored by females, testes size and ectodermal accessory glands size were not affected by male identity, while sterile 100 Gy males had larger mesodermal accessory glands than control lab males. A reduction in irradiation dose does not impact any variable measured, except for percentage of sperm-depleted females: females mated with sterile 100 Gy males had lower probabilities to store sperm. The results showed here are very encouraging for tsl Vienna 8 strain reared in Argentina and are discussed in comparison with previous studies in C. capitata female remating with dissimilar results.

Ascertaining the causes of adaptive radiation is central to understanding how new species arise and come to vary with their resources. The ecological theory posits adaptive radiation via divergent natural selection associated with novel resource use; an alternative suggests character displacement following speciation in allopatry and then secondary contact of reproductively isolated but ecologically similar species. Discriminating between hypotheses, therefore, requires the establishment of a key role for ecological diversification in initiating speciation versus a secondary role in facilitating co-existence. Here, we characterize patterns of genetic variation and postzygotic reproductive isolation for tephritid fruit flies in the Rhagoletis cingulata sibling species group to assess the significance of ecology, geography, and non-adaptive processes for their divergence. Our results support the ecological theory: no evidence for intrinsic postzygotic reproductive isolation was found between two populations of allopatric species, while nuclear-encoded microsatellites implied strong ecologically based reproductive isolation among sympatric species infesting different host plants. Analysis of mitochondrial DNA suggested, however, that cytoplasmic-related reproductive isolation may also exist between two geographically isolated populations within R cingulata. Thus, ecology associated with sympatric host shifts and cytoplasmic effects possibly associated with an endosymbiont may be the key initial drivers of the radiation of the R. cingulata group.