ABSTRACT
There has been considerable interest in understanding biological, ecological, historical, and evolutionary processes that contribute to the diversification of species and populations among tephritid fruit flies. Only a limited number of studies have examined the genetic diversity and population biology of species belonging to the genus Anastrepha considering fine-scale differentiations associated to locality as well as hosts over an entire fruiting season. To expand our understanding of population structure and genetic diversity in one of the critical Anastrepha fruit flies populations in a highly diverse tropical environment we analyzed Anastrepha obliqua (Macquart) (Diptera: Tephritidae) in the Mexican state of Veracruz from five host fruit species and 52 geographic collections using sequence data from mtDNA and microsatellite markers from nuclear DNA. Indeed, we examined the population structure of this pest in a micro-geographic region and report on relationships and historical processes for individuals collected within a small portion of the geographic range of its distribution. Analyses of 1055 bp mtDNA sequences from CO1and ND1genes across 400 individuals detected 34 haplotypes. Haplotype and nucleotide diversity was low, with 53% of the individuals exhibiting a single haplotype (OBV1). Host association and fine-scale differentiation at 17 microsatellite markers across 719 individuals from 32 of the 52 geographic collections reveal fragmented A. obliqua populations. These findings have important implications for the implementation of the Sterile Insect Technique (SIT) and other pest management programs used to control this pestiferous fruit fly.
Subject(s)
Tephritidae , Animals , DNA, Mitochondrial , Fruit , Genetic Variation , Species SpecificityABSTRACT
Anastrepha obliqua (Macquart), the West Indian fruit fly, is one of the most economically important pest species in the Neotropical region. It infests an extensive range of host plants that include over 60 species. The geographic range of A. obliqua is from northern Mexico to southern Brazil and includes the Caribbean Islands. Previous molecular studies have revealed significant genetic structure among populations. We used sequences from a fragment of the mitochondrial protein-coding gene cytochrome c oxidase I to estimate structure and genetic diversity of A. obliqua populations from Brazil. We analyzed a total of 153 specimens from the Amazon Forest, Atlantic Forest, Cerrado, and Caatinga biomes. Our study revealed weak genetic structure among the A. obliqua Brazilian populations sampled. Collections from the Amazon Forest had similar haplotype diversity compared to previously reported estimates for collections from the Caribbean and both populations are also closely related to each other, thus challenging the hypothesis that A. obliqua originated in the Caribbean and then moved to other regions of the Americas. Therefore, further evidence is necessary to draw a definite conclusion about the putative center of origin for A. obliqua. Additionally, we suggest a putative historical migration from the west to the east for the A. obliqua Brazilian populations, which could explain the high genetic diversity for this fly in the Amazon Forest and low genetic diversity in the other Brazilian biomes.
Subject(s)
Tephritidae/genetics , Animal Distribution , Animals , Biodiversity , Brazil , DNA, Mitochondrial , Forests , Genetic Structures , PhylogenyABSTRACT
Anastrepha ludens (Loew) (Diptera: Tephritidae), the Mexican fruit fly, is a major pest of citrus and mango. It has a wide distribution in Mexico and Central America, with infestations occurring in Texas, California, and Florida with origins believed to have been centered in northeastern Mexico. This research evaluates the utility of a sequence-based approach for two mitochondrial (COI and ND6) gene regions. We use these markers to examine genetic diversity, estimate population structure, and identify diagnostic information for A. ludens populations. We analyzed 543 individuals from 67 geographic collections and found one predominant haplotype occurring in the majority of specimens. We observed 68 haplotypes in all and see differences among haplotypes belonging to northern and southern collections. Mexico haplotypes differ by few bases possibly as a result of a recent bottleneck event. In contrast to the hypothesis suggesting northeastern Mexico as the origin of this species, we see that specimens from two southern collections show high genetic variability delineating three mitochondrial groups. These data suggest that Central America is the origin for A. ludens. We show that COI and ND6 are useful for phylogeographic studies of A. ludens.
Subject(s)
Genetic Variation , Tephritidae/genetics , Animals , Central America , DNA, Mitochondrial/genetics , DNA, Mitochondrial/metabolism , Electron Transport Complex IV/genetics , Electron Transport Complex IV/metabolism , Genome, Mitochondrial , Haplotypes , Insect Proteins/genetics , Insect Proteins/metabolism , Larva/growth & development , Larva/metabolism , Mexico , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , Molecular Sequence Data , Phylogeny , Phylogeography , Sequence Analysis, DNA , Tephritidae/growth & development , Tephritidae/metabolismABSTRACT
Foi analisado um fragmento de 808 pares de base do gene mitocondrial citocromo oxidase I (COI) para 15 espécies de Anastrepha: 12 pertencentes ao grupo fraterculus, uma espécie sem grupo definido e duas como grupo externo. As relações filogenéticas entre os táxons incluídos foram inferidas pelos métodos de "neighbor-joining" e máxima parcimônia. A distância genética média (Jukes-Cantor) entre as espécies foi 0,033 ± 0,006, tendo o nível de divergência das seqüências variado de 0,0 a 0,083. Os resultados do estudo com o COI indicaram a inclusão de A. acris Stone, espécie sem grupo morfologicamente definido, no grupo fraterculus. A inclusão de A. barbiellinii Lima no grupo fraterculus e a monifilia do referido grupo são também discutidas. Além disso, a presença de múltiplos conjuntos gênicos na espécie nominal A. fraterculus (Wiedemann) e a não-monofilia de A.fraterculus são corroboradas pelos dados obtidos no presente estudo. As espécies A. amita Zucchi, A. turpiniae Stone e A. zenildae Zucchi foram analisadas geneticamente pela primeira vez.
A fragment of 808 base pairs within the mtDNA gene cytochrome oxidase I (COI) was analyzed for 15 species of Anastrepha: 12 within the fraterculus group, one unplaced species and two outgroups. Phylogenetic relationships among the included taxa were inferred using neighbor-joining and maximum parsimony methods. The average Jukes-Cantor genetic distance among the species was 0.033±0.006 and the level of sequence divergence ranged from 0.0 to 0.083. Our results of COI indicate the placement of A. acris Stone, an unplaced species, in the fraterculus group. The membership of A. barbiellinii Lima in the fraterculus group and the monophyly of the aforementioned group are also discussed. Moreover, the presence of multiple gene pools in the nominal species A. fraterculus (Wiedemann) and the nonmonophyly of A. fraterculus are corroborated by data obtained in our study. The species A. amita Zucchi, A. turpiniae Stone and A. zenildae Zucchi were genetically studied for the first time.