Gary J. Steck

FIRST RECORDS OF ZAPRIONUS INDIANUS (DIPTERA: DROSOPHILIDAE), A PEST SPECIES ON COMMERCIAL FRUITS FROM PANAMA AND THE UNITED STATES OF AMERICA

Zaprionus indianus Gupta 1970 (Diptera: Drosophilidae) is native to Africa, the Middle East, and southern Eurasia (Chassagnard & Kraaijeveld 1991; Baichli 1999-2005). It was first found in the Americas in 1999, when it was reported from Sao Paulo, Brazil (Vilela 1999). Since then, it has spread rapidly through Brazil (Santos et al. 2003; Tidon et al. 2003; Ledo & Tidon 2004; da Silva et al. 2005) and Uruguay (Goni et al. 2001, 2002) and has been predicted to reach the USA in the near future (David et al. 2006). Here we report the first records of Z. indianus from Panama and the USA. On 6 and 7 Oct 2003, DH collected several individuals of Z. indianus on Isla Contadora, Panama. KH reared several individuals of Zaprionus (Steck 2005) from fruits of longan, Dimocarpus longan Lour., and Barbados cherry, Malpighia emarginata Sess6 & Moc. ex DC., collected on 26 Jul 2005 in St. Lucie Co., Florida. Dr. C. Ribeiro Vilela confirmed the identification as Z. indianus.

Geographic populations of the medfly may be differentiated by mitochondrial DNA variation

Restriction enzyme cleavage sites of mitochondrial DNA (mtDNA) from the Mediterranean fruit fly were found to vary among introduced populations in the Neotropics. The survey included samples from 15 established natural populations and 5 laboratory cultures from Hawaii, Central America, South America and West Africa and samples from recent California infestations (1989, 1991). Based on restriction fragment length polymorphisms from 2 enzymes, Hawaii is an unlikely source for the 1989 and 1991 California infestations. Interpopulational variation in mtDNA demonstrates the potential for the technique to trace the process of colonization (geographic spread) by this insect.

Analysis of mitochondrial DNA and development of PCR-based diagnostic molecular markers for Mediterranean fruit fly (Ceratitis capitata) populations.

A 2.99 kb mtDNA fragment containing two variable restriction endonuclease sites (EcoRV and Xbal) was subcloned and sequenced from the Mediterranean fruit fly (Ceratitis capitata). This fragment represents approximately one‐fifth of the entire mitochondrial sequence. The sequence was aligned with the comparable region from Drosophila yakuba and Anopheles gambiae, resulting in 81.8% and 76.7% identity at the nucleotide level, and 77% and 67.7% identity, respectively, at the amino acid level. The sequenced region includes the complete genes for NADH dehydrogenase 4, NADH dehydrogenase 4L, NADH dehydrogenase 6, and transfer RNAs for proline, threonine and histidine, and part of the genes for NADH dehydrogenase 5 and cytochrome b. Oligonucleotide primers were designed to asymmetrically bracket each of two variable restriction endonuclease sites to allow PCR amplification and subsequent restriction endonuclease analysis of individual fly samples.

Mitochondrial DNA Restriction Map for the Mediterranean Fruit Fly, Ceratitis capitata

Molecular genetic research on the Mediterranean fruit fly,Ceratitis capitata, will provide tools to permit determination of source populations for new pest infestations. Restriction fragment length polymorphism (RFLP) of mitochondrial DNA provides some interpopulation discrimination. A restriction map, including the informative variableEcoRV andXbaI restriction sites, is constructed for the Mediterranean fruit fly, and several restriction sites are associated with specific gene regions based on polymerase chain reaction-RFLP and sequence analyses. A partial sequence of the mitochondrial 16S ribosomal RNA gene is reported.

New Report of Chaetopsis massyla (Diptera: Ulidiidae) as a Primary Pest of Corn in Florida

ABSTRACT The picture-winged fly Euxesta stigmatias Loew (Diptera: Ulidiidae) has been a serious pest of sweet corn in Florida since the 1930s and had been considered the only fly infesting Florida corn. In a sweet corn variety trial to evaluate E. stigmatias resistance in 2007, adult Chaetopsis massyla (Walker) (Diptera: Ulidiidae) was reared from the ears. Choice and no-choice trials were conducted in 2007 and 2008 to determine the pest nature of C. massyla on corn. In no choice tests, C. massyla pairs were caged on uninfested corn ears in green house and field trials. In choice tests, field collected corn ears were held for fly emergence. No choice tests showed that C. massyla could infest and complete development in ears that had no previous damage. Chaetopsis massyla emerged from corn ears with and without prior infestation by other insect species in choice tests. Subsequently, C. massyla were reared from corn ears collected from locations throughout the major sweet corn growing region of southern Florida. Therefore, we present what we believe to be the first report of C. massyla as a primary pest of corn ears in Florida and in the United States of America.

Alternative plants for development of picture-wingedfly pests of maize

Eleven species of picture‐winged flies (Diptera: Ulidiidae: Lipsanini) have been reported attacking maize [Zea mays L. (Poaceae)] ears in the Americas. Four of these species are sweet corn pests in America north of Mexico: Chaetopsis massyla (Walker), Euxesta annonae (Fabricius), E. eluta Loew, and E. stigmatias Loew. Adults of these four species appear at the beginning of each season following maize‐free periods, suggesting other plants act as food sources for maintenance and development of these flies. Studies were conducted in Florida, USA, to evaluate the suitability of several crop and non‐crop plants commonly occurring near maize plantings as developmental hosts for these flies. Laboratory trials were conducted using laboratory colonies of C. massyla, E. eluta, and E. stigmatias to determine their developmental rates and pupal survivorship on roots, stems, leaves, or fruits of 14 crop and weed species. All three fly species completed development on all tested crops (Brassica oleracea L., Capsicum chinense Jacquin, Capsicum annum L., Carica papaya L., Persea americana Mill., Raphanus sativus L., Saccharum officinarum L., and Solanum lycopersicum L.) and weed species [Amaranthus spinosus L., Portulaca oleracea L., Sorghum halepense (L.), and Typha spp.], except for Daucus carota L. roots and Solanum tuberosum L. tubers. Findings of the current study suggest that the presence of multiple host crops in areas surrounding maize fields may help explain the occurrence of these maize‐infesting ulidiids immediately after prolonged absences of maize.

Distribution of Picture-Winged Flies (Diptera: Ulidiidae) Infesting Corn in Florida

ABSTRACT The picture-winged fly Euxesta stigmatias Loew (Diptera: Ulidiidae) has been a serious pest of sweet corn (Zea mays L.) in Florida since 1930. Several other species in the family are known to infest corn grown in the Caribbean, Central America, and South America. Surveys were conducted throughout Florida to evaluate species richness and distribution of corn-infesting Ulidiidae. Adults were sampled with sweep nets and reared from fly larvae-infested corn ears collected from representative corn fields in 16 and 27 counties in 2007 and 2008, respectively. Four Ulidiidae species were found in corn fields using both sampling techniques. Euxesta eluta Loew and Chaetopsis massyla (Walker) were found throughout the state on field and sweet corn. Euxesta stigmatias was only found in Martin, Miami-Dade, Okeechobee, Palm Beach, and St. Lucie Counties on field and sweet corn. Euxesta annonae (F.) was found in sweet corn in Miami-Dade, Okeechobee, and Palm Beach Counties, but field corn was not sampled in these counties. Euxesta eluta, E. stigmatias, and C. massyla were collected from corn throughout the corn reproductive stage. Raising adults from fly larvae-infested ears provided the best method for assessing rates of ear infestation and species richness. Sweep netting did not provide reliable information on the presence or species composition of ulidiid species infestation. We report for the first time E. annonae and E. eluta as pests of corn in Florida and the USA.

Egg Morphology of Anastrepha spp. (Diptera: Tephritidae) in the fraterculus Group using Scanning Electron Microscopy

ABSTRACT We describe detailed scanning electron microscopic (SEM) observations of eggs of six Anastrepha species in the fraterculus group: Anastrepha antunesi Lima, Anastrepha bahiensis Lima, Anastrepha coronilli Carrejo & González, Anastrepha distincta Greene, Anastrepha turpiniae Stone, and Anastrepha zenildae Zucchi, for the first time. Eggs were dissected from females captured in McPhail traps in Cariri in the state of Tocantins; Itacoatiara, Manaus, and Presidente Figueiredo in the state of Amazonas; and Porto Velho in the state of Rondônia, in the Brazilian Amazon. Eggs were examined using both scanning electron and optical microscopes. At least 10 eggs were examined for each species by using SEM, and 20–35 eggs per female of at least three females of each species were prepared for light microscopy. The eggs of all six species are similar in gross morphology. They are tapered at both ends, have a papilla at the anterior pole, and the micropyle is located on the dorsal side near the anterior pole. Diagnostic characters to differentiate among these six species include the chorion ornamentation, location of aeropyles, and a pronounced rim of the chorion with a woolly appearance surrounding the micropyle. None of the eggs of the studied species had a conspicuous respiratory appendage.

Discrimination of Caribbean and Mediterranean fruit fly larvae (Diptera: Tephritidae) by cuticular hydrocarbon analysis.

Larvae of the Caribbean fruit fly, Anastrepha suspensa (Loew) can be differentiated from those of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) with nearly 100% accuracy by analysis of cuticular hydrocarbon (CHC) patterns. A discriminant model is presented based on samples of feral and laboratory Caribbean and Mediterranean fruit flies. The difference in the ratio of two components is sufficient to discriminate third instars of the species. Accuracy in discrimination, utilization of specimens that are damaged, dried or otherwise unusable for morphometric, isozyme or DNA analysis, low cost per sample and automation of the process, all make CHC analysis a particularly effective solution for identification of these two species.

Nuclear ribosomal internal transcribed spacer 1 (ITS1) variation in the Anastrepha fraterculus cryptic species complex (Diptera, Tephritidae) of the Andean region.

Abstract The nuclear ribosomal internal transcribed spacer 1 (ITS1) was sequenced for Anastrepha fraterculus (Wiedemann, 1830) originating from 85 collections from the northern and central Andean countries of South America including Argentina (Tucumán), Bolivia, Perú, Ecuador, Colombia, and Venezuela. The ITS1 regions of additional specimens (17 collections) from Central America (México, Guatemala, Costa Rica, and Panamá), Brazil, Caribbean Colombia, and coastal Venezuela were sequenced and together with published sequences (Paraguay) provided context for interpretation. A total of six ITS1 sequence variants were recognized in the Andean region comprising four groups. Type I predominates in the southernmost range of Anastrepha fraterculus. Type II predominates in its northernmost range. In the central and northern Andes, the geographic distributions overlap and interdigitate with a strong elevational effect. A discussion of relationships between observed ITS1 types and morphometric types is included.