Robert A. Wharton

Hymenopteran parasitoids on fruit-infesting Tephritidae (Diptera) in Latin America and the southern United States: Diversity, distribution, taxonomic status and their use in fruit fly biological control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.

Finding Our Way through Phenotypes

Imagine if we could compute across phenotype data as easily as genomic data; this article calls for efforts to realize this vision and discusses the potential benefits.

Predicted Secondary Structure for 28S and 18S rRNA from Ichneumonoidea (Insecta: Hymenoptera: Apocrita): Impact on Sequence Alignment and Phylogeny Estimation

We utilize the secondary structural properties of the 28S rRNA D2–D10 expansion segments to hypothesize a multiple sequence alignment for major lineages of the hymenopteran superfamily Ichneumonoidea (Braconidae, Ichneumonidae). The alignment consists of 290 sequences (originally analyzed in Belshaw and Quicke, Syst Biol 51:450–477, 2002) and provides the first global alignment template for this diverse group of insects. Predicted structures for these expansion segments as well as for over half of the 18S rRNA are given, with highly variable regions characterized and isolated within conserved structures. We demonstrate several pitfalls of optimization alignment and illustrate how these are potentially addressed with structure-based alignments. Our global alignment is presented online at (http://hymenoptera.tamu.edu/rna) with summary statistics, such as basepair frequency tables, along with novel tools for parsing structure-based alignments into input files for most commonly used phylogenetic software. These resources will be valuable for hymenopteran systematists, as well as researchers utilizing rRNA sequences for phylogeny estimation in any taxon. We explore the phylogenetic utility of our structure-based alignment by examining a subset of the data under a variety of optimality criteria using results from Belshaw and Quicke (2002) as a benchmark.

Parasitoids of medfly, Ceratitis capitata, and related tephritids in Kenyan coffee: a predominantly koinobiont assemblage

Arabica coffee was sampled from two sites in the central highlands of Kenya (Rurima, Ruiru) and one site on the western side of the Rift Valley (Koru). Three species of ceratitidine Tephritidae, Ceratitis capitata (Wiedemann), C. rosa Karsch and Trirhithrum coffeae Bezzi, were reared from sites in the central highlands, and an additional species, C. anonae Graham, was recovered from the western-most site. Ten species of parasitic Hymenoptera were reared from these tephritids. The parasitoid assemblage was dominated by koinobionts. Eight of the species are koinobiont endoparasitoids, but only one idiobiont larval ectoparasitoid was reared, and only one idiobiont pupal endoparasitoid. The effects of sampling bias on determination of parasitoid assemblage size associated with concealed hosts are discussed. The potential for use of these parasitoids in biological control is also discussed. Most of the parasitoid species recovered during this study are capable of developing on C. capitata, while several also attack C. rosa. Both flies are notorious pests of tropical and subtropical fruits.

Geographic Distribution, Host Fruit, and Parasitoids of African Fruit Fly Pests Ceratitis anonae, Ceratitis cosyra, Ceratitis fasciventris, and Ceratitis rosa (Diptera: Tephritidae) in Kenya

Abstract The fruit of indigenous, cultivated, and naturalized exotic plants was sampled in Kenya to determine the geographical and host plant distributions of the fruit fly pests Ceratitis anonae (Graham), Ceratitis cosyra (Walker), Ceratitis fasciventris (Bezzi), and Ceratitis rosa Karsch. In 1997, cultivated and wild fruit were sampled on the Kenya coast to determine seasonal patterns of host use by C. cosyra and C. rosa. From 1999 to 2004, the sampling effort was expanded to forested areas of the central and western highlands and to all fruit-infesting tephritids. Together, the four pest tephritid species were reared from 5.1% of 3,794 fruit collections, the latter making up 116 families and 882 species of host plants. C. anonae, C. cosyra, C. fasciventris, and C. rosa were reared throughout Kenya, from 14, 9, 30, and 28 plant species, respectively. Fifty-two of these plants represented previously unknown hosts for one or more of the tephritids. C. anonae was restricted to habitats west of the Gregory Rift Valley. C. fasciventris was found in western and central Kenya, but it was not reared from coastal fruit collections. C. rosa occurred at the coast and in central highland fruit. We provide evidence for the recent introduction of C. rosa into the central highlands. Only C. cosyra was found in habitats located in all three of the major regions sampled. Although distributed over a wider geographic area than the other species, C. cosyra had a markedly restricted host range. On the coast, C. cosyra used wild fruit, primarily Sclerocarya birrea (A. Rich.) Hochst. (Anacardiaceae), as hosts when mango was not fruiting. C. rosa was absent from our mango samples but attacked common guava and wild fruit species. Overall, C. anonae, C. fasciventris, and C. rosa had similar host profiles, but each also had unique hosts in which infestations were usually heavy. Members of the Sapotaceae and Annonaceae were the most important wild hosts of these three species. Within these families, host fruit were partitioned among these tephritid species and the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). The availability of wild host fruit, sometimes supplemented by naturalized invasive plants or cultivated fruit, provided for year-round breeding of C. anonae and C. fasciventris, whereas indigenous fruit were sufficient for breeding of C. rosa and C. cosyra during most of the year. Opiine braconids were reared from all four species of Ceratitis.

Indigenous hosts of Ceratitis capitata (Diptera: Tephritidae) in Kenya.

Abstract To study the relationship of Mediterranean fruit fly or medfly, Ceratitis capitata (Wiedemann), to native plant hosts in an area within its original home range, fruits were sampled in diverse areas of Kenya from 1999 to 2001. Sampling effort was concentrated in and around forested areas in coastal, central highland, and western highland habitats. Medflies were reared from fruits of 55 species of plants, 51 of them indigenous; 46 of these species represent previously unknown hosts in Africa. Fruits infested by C. capitata were collected in all study sites, east and west of the Gregory Rift Valley, in xeric habitats between the coast and the central highlands, and at altitudes from sea level to 2,164 m above sea level. The conditions for year-round breeding of medfly in indigenous fruits are present at the coast, and possibly in highland areas as well. Infestation indices were comparable to those reported elsewhere from cultivated fruits. Although polyphagous in its home range, C. capitata was not distributed uniformly among species within two important host-plant families, Sapotaceae and Rubiaceae.

Fruit Flies of the Genus Anastrepha (Diptera: Tephritidae) and Associated Native Parasitoids (Hymenoptera) in the Tropical Rainforest Biosphere Reserve of Montes Azules, Chiapas, Mexico

Abstract We report the results of a 2-yr survey that determined some of the host plant and parasitoid associations of Anastrepha fruit flies (Diptera: Tephritidae) in the “Montes Azules” tropical rainforest biosphere reserve (State of Chiapas, Mexico). We collected a total of 57.38 kg of fruit representing 47 native species from 23 plant families. Of these, 13 plant species from eight plant families were found to be native hosts of 9 species of Anastrepha. The following Anastrepha host associations were observed: Bellucia pentamera Naudin (Melastomataceae) with A. coronilli Carrejo y González; Malmea gaumeri (Greenm.) Lundell (Annonaceae) with A. bahiensis Lima; Tabernamontana alba Mill. (Apocynaceae) with A. cordata Aldrich; Quararibea yunckeri Standl. (Bombacaceae) with A. crebra Stone; Ampelocera hottlei (Standl.) Standl. (Ulmaceae) with A. obliqua (Macquart) and A. fraterculus (Wiedemann); Zuelania guidonia Britton and Millsp. and Casearia tremula (Griseb.) Griseb. ex C. Wright (Flacourtaceae) with A. zuelaniae Stone; Psidium sartorianum (O. Berg.) Nied (Myrtaceae) with A. fraterculus; Psidium guajava L. and P. sartorianum (Myrtaceae) with A. striata Schiner; and Manilkara zapota (L.) Van Royen, Pouteria sp., Bumelia sebolana Lundell, and Calocarpum mammosum (L.) Pierre (Sapotaceae) with A. serpentina (Wiedemann). The following are new host plant records: Malmea gaumeri for A. bahiensis; Quararibea yunckeri for A. crebra; Ampelocera hottlei for A. fraterculus and A. obliqua; Bumelia sebolana for A. serpentina; and Casearia tremula for A. zuelaniae. A. coronilli is reported for the first time in Mexico. Infestation levels were variable and ranged between 0 and 1.63 larvae/g of fruit depending on host species. Larvae of eight species of Anastrepha on nine plant species from six plant families were found to be parasitized by Doryctobracon areolatus Szepligeti, D. crawfordi Viereck, D. zeteki Musebeck (new report for Mexico and northernmost record for the species), Opius hirtus Fisher, Utetes anastrephae Viereck (all Hymenoptera: Braconidae), and Aganaspis pelleranoi Brethes (Hymenoptera: Figitidae). Percent parasitism ranged from 0 to 76.5%. We discuss our findings in light of their practical (e.g., biological control) and theoretical (e.g., species radiation) implications and highlight the importance of these types of studies given the rampant deforestation of tropical forests in Latin America and the risk of extinction of rare fruit fly species that could shed light on the evolution of host plant and parasitoid associations within the genus Anastrepha.

Variation and the phylogenetic utility of the large ribosomal subunit of mitochondrial DNA from the insect order Hymenoptera.

Nucleotide sequence variation from a 573-bp region of the mitochondrial 16S rRNA gene was determined for representative hymenopteran taxa. An overall bias in the distribution of A and T bases was observed from all taxa; however, the terebrants (parasitoids) displayed significantly lower AT ratios as well as a higher degree of strand asymmetry. Moreover, a strong positive correlation was observed between relative AT richness and sequence divergence, suggesting selection at the nucleotide level for A and T bases as well as functionality. Overall sequence difference ranged from 2.3 to 53.4%, with the maximum divergence between members of the two Hymenopteran suborders. These data were used in a phylogenetic analysis to illustrate the utility and degree of resolution provided by this information at various hierarchical levels within this taxonomically diverse order. Parsimony analysis revealed strong evidence for monophyly of the aculeates and the terebrants. Most noteworthy was a strongly supported clade containing the two terebrant superfamilies Icheumonoidea and Chalcidoidea. Conversely, high sequence divergence values resulted in instability at the base of the tree and limited resolution at the higher taxonomic levels. Nevertheless, these results do identify those taxonomic levels for which 16S rRNA sequences are phylogenetically informative.

Host specificity of Psyttalia cosyrae (Hymenoptera: Braconidae) and the effect of different host species on parasitoid fitness

Abstract Psyttalia cosyrae (Wilkinson) (Hymenoptera: Braconidae) is a synovigenic, koinobiont larval-pupal parasitoid of Ceratitis cosyra (Walker) (Diptera: Tephritidae), and possibly other tephritid fruit flies. Host acceptance and suitability of medfly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), mango fruit fly, Ceratitis cosyra , Natal fruit fly, Ceratitis rosa Karsch, Ceratitis fasciventris (Bezzi), Ceratitis anonae Graham, and melon fruit fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), for oviposition and development of this parasitoid were investigated. The effect of different host species on traits widely used to assess parasitoid fitness was also evaluated. Psyttalia cosyrae accepted all host species tested, but acceptance varied. In no choice tests, C. cosyra and C. capitata were accepted at a significantly higher rate than the other four species. The parasitoid successfully developed only in C. cosyra and C. capitata . Eggs oviposited in C. rosa , C. fasciventris , C. anonae , and B. cucurbitae were encapsulated. Developmental time was shorter in C. capitata than in C. cosyra , but parasitoid progeny emerging from the latter host were more fit, as measured by percent female progeny, adult size, egg load, and adult survival.

Abundance of Anastrepha fraterculus (Diptera: Tephritidae) and Its Associated Native Parasitoids (Hymenoptera) in “Feral” Guavas Growing in the Endangered Northernmost Yungas Forests of Argentina with an Update on the Taxonomic Status of Opiine Parasitoids Previously Reported in This Country

Abstract We report the results of a 2-yr survey aimed at determining the identity and abundance of native parasitoids of fruit infesting tephritids attacking Psidium guajava L. (common guava) in the endangered northernmost Yungas forests of Argentina, which are being encroached by commercial citrus groves. The 3,200 guavas collected during the peak of the short guava fruiting period (February and March), yielded 10,701 Anastrepha fraterculus (Wiedemann) and Ceratitis capitata (Wiedemann) adults (97.4 and 2.6%, respectively) and 712 native parasitoids. The parasitoid species and proportion in the total sample during the 2-yr study period were as follows: Doryctobracon areolatus (Szépligeti), 37.9%; Doryctobracon brasiliensis (Szépligeti), 17.7%; Utetes anastrephae (Viereck), 1.1%; Opius bellus (Gahan), 0.7%; (all Braconidae, Opiinae), and Aganaspis pelleranoi (Brèthes), 32.6% (Figitidae, Eucoilinae). All parasitoids emerged from A. fraterculus pupae (i.e., none from C. capitata). The discovery of D. crawfordi represents the first report for Argentina and the southernmost record for the species. We discuss the practical implications of the role of guava as a reservoir for A. fraterculus and the implications for the biological control of both fruit flies. We also update the taxonomic status of the opiine parasitoids of A. fraterculus in Argentina given that a number of species previously reported in the literature had never been formally described (i.e., represent nomina nuda) or had been misidentified.