Although a large amount of data have been published in past years on the taxonomic status of the Anastrepha fraterculus (Wiedemann) species complex, there is still a need to know how many species this complex comprises, the distribution of each one, and their distinguishing features. In this study, we assessed the morphometric variability of 32 populations from the A. fraterculus complex, located in major biogeographical areas from the Neotropics. Multivariate techniques for analysis were applied to the measurements of 21 variables referring to the mesonotum, aculeus, and wing. For the first time, our results identified the presence of seven distinct morphotypes within this species complex. According to the biogeographical areas, populations occurring in the Mesoamerican dominion (Mexico, Guatemala, and Panama) were clustered within a single natural entity labeled as the “Mexican” morphotype; whereas in the northwestern South American dominion, samples fell into three distinct groups: the “Venezuelan” morphotype with a single population from the Caribbean lowlands of Venezuela, the “Andean” morphotype from the highlands of Venezuela and Colombia, and the third group or “Peruvian” morphotype comprised the samples from the Pacific coastal lowlands of Ecuador and Peru. Three additional groups were identified from the Chacoan and Paranaense sub-regions: the morphotype “Brazilian-1” was recognized as including the Argentinean samples with most pertaining to Brazil, and widely distributed in these biogeographical areas; the morphotype “Brazilian-2” was recognized as including two samples from the state of Sao Paulo (Ilha-Bela and São Sebastião); whereas the morphotype “Brazilian-3” included a single population from Botucatu (state of Sao Paulo). Based on data published by previous authors showing genetic and karyotypic differentiation, as well as reproductive isolation, we have concluded that such morphotypes indeed represent natural groups and distinct taxonomic entities.
The South American fruit fly Anastrepha fraterculus (Wiedemann) is a complex of cryptic species, the so-called “Anastrepha fraterculus complex”, for which eight morphotypes are currently recognized. A previous analysis of ITS1 in samples of the Anastrepha fraterculus complex, while revealing high distinctiveness among samples from different localities of South America, Central America, and Mexico, no direct association was made between sequence type and morphotype. In the present report, a correlated analysis of morphometry and ITS1 data involved individuals belonging to the same population samples. Although showing a low level of intra-populational nucleotide variability, the ITS1 analysis indicated numerous inter-population sequence type variants. Morphotypes identified by morphometric analysis based on female wing shape were highly concordant with ITS1 genetic data. The correlation of genetic divergence and morphological differences among the tested samples gives strong evidence of a robust dataset, thereby indicating the existence of various taxonomic species within the A. fraterculus complex. However, the data revealed genetic and morphological variations in some regions, suggesting that further analysis is still required for some geographic regions.
Mepraia spinolai is an endemic species in Chile that lives in wild and domestic habitats. It is the only species of the Reduviidae family that shows alate polymorphism; females are always wingless, but males can be found with and without wings. The M. spinolai karyotype consists of 10 pairs of autosomes and a complex sex determination system. Males from the northernmost regions I and II (latitude 18°-26° South) are always winged (braquipterous) and are X1X2Y, with a large Y chromosome. From region III to the metropolitan region (latitude 26°-33° South), males may be either winged or wingless but appear to be polymorphic for a small neo-Y chromosome, which may have originated by fracture of the large holocentric Y chromosome found in populations from farther north. Experimental crosses suggest that the genes for wings are linked in the Y chromosome and also that there are two cytologically indistinguishable types of neo-Y chromosomes. One form (Y1) bears a gene or genes for wings while the other (Y2) lacks such genes. Males that are X1X2Y1, X1X2Y1Y1 and X1X2Y1Y2 are winged, while the absence of Y1 (X1X2Y2 and X1X2Y2Y2 ) results in a wingless male. These chromosomes and morphological changes are correlated with a shift of the southern population into more arid habitats of the interior in the metropolitan region and region III.
Mepraia spinolai é uma espécie endêmica no Chile que mora em habitats domésticos e silvestres. É a única espécie da família Reduviidae que apresenta polimorfismo de asas: as fêmeas são sempre sem asas, mas os machos podem ou não tê-las. O cariótipo de M. spinolai consiste de 10 pares de autossomos e um sistema complexo de determinação do sexo. Os machos das regiões mais setentrionais, regiões I e II (latitude 18o-26o S), sempre têm asas (braquíteros) e são X1X2Y, com um grande cromossomo Y. Da região III à região metropolitana (latitude 26o-33o S), os machos podem ou não ter asas, mas parecem ser polimórficos para um pequeno neo-cromossomo Y que pode ter se originado por fratura do grande cromossomo Y holocêntrico encontrado nas populações mais ao norte. Cruzamentos experimentais sugerem que os genes para asas estão ligados no cromossomo Y e também que há dois tipos citologicamente indistinguíveis de neo-cromossomo Y: uma forma (Y1) é portadora de um gene ou de genes para asas, enquanto que a outra (Y2) não apresenta tais genes. Os machos que são X1X2Y1, X1X2Y1Y1 e X1X2Y1Y2 têm asas, enquanto que a ausência de Y1 (X1X2Y2 e X1X2Y2Y2 ) resulta em um macho sem asa. Esses cromossomos e as modificações morfológicas correlacionam-se com uma mudança da população do sul para habitats mais áridos do interior da região metropolitana e da região III
Neotropical Entomology 37(5): 536-545 (2008) Morfologia dos Estados Imaturos da Espécie de Mosca das Frutas Neotropical não Frugívoradobras da cutícula, as margens da abertura oral, o esqueleto cefalofaríngeo, os espiráculos anterior e posterior e os lóbulos anais das larvas de primeiro, segundo, terceiro estádios e da pupa. O esqueleto cefalofaríngeo é altamente esclerotizado e apresenta um orifício ou abertura na cornua ventral, característica essa que parece ser plesiomórfi ca em R. limbata e outras espécies neotropicais. Os espiráculos anteriores estão ausentes nas larvas de primeiro estádio. Nas larvas de segundo e terceiro estádios são desenvolvida formando cinco túbulos curtos dispostos em fi leira única. Nas larvas de primeiro e segundo estádios, as aberturas dos espiráculos têm cerdas únicas; nas larvas de terceiro estádio não há cerdas. Essa última característica parece decorrer de uma atraso no desenvolvimento (neotenia) da larva de R. limbata, quando comparada a outras espécies neotropicais e neárticas.PALAVRAS-CHAVE: Adaptação, neotenia, caráter plesiomórfi co, apomórfi co ABSTRACT -Rachiptera limbata Bigot develops on Baccharis linearis (R. et Pav.) in the areas around Santiago, Chile. The larvae feed on stem tissues and secrete a liquid that hardens to form a protective feeding and pupation chamber. The immature stages of Neotropical species of Tephritinae are poorly known. In this paper, the morphology of the immature stages of R. limbata are described and compared, in a phylogenetic context, with other Tephritinae species. Antennomaxillary complex, pads, oral ridge, cephalopharyngeal skeleton, anterior and posterior spiracles and anal lobes of fi rst-, second-, third-instar larvae and pupae were studied with optical and scanning electron microscopy. The cephalopharyngeal skeleton is darkly sclerotized and shows an opening or window in the ventral cornua. This trait seems to be plesiomorphic in R. limbata and in other Neotropical species. First-instar larvae anterior spiracles are absent; whereas in second and third instars spiracles are developed as a row of fi ve short tubules. In fi rst-and second-instar larvae, the posterior spiracular slit has only a single hair per bundle; whereas third-instar larvae lack hairs. This last trait seems to be consequence of a larval development delay and an apomorphic trait in R. limbata, compared to other Neotropical and Neartical species.
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