Incipient speciation revealed in Anastrepha fraterculus (Diptera; Tephritidae) by studies on mating compatibility, sex pheromones, hybridization, and cytology

Authors

  • CARLOS CÁCERES,

    1. Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, IAEA Laboratories, A-2444 Seibersdorf, Austria
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  • DIEGO F. SEGURA,

    1. Laboratorio de Genética de Insectos de Importancia Económica, IGEAF, INTA Castelar, Los Reseros y Las Cabañas, Castelar (1712), Buenos Aires, Argentina
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  • M. TERESA VERA,

    1. Estación Experimental Agroindustrial Obispo Colombres, William Cross 3150, Las Talitas (4101), Tucumán, Argentina
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  • VIWAT WORNOAYPORN,

    1. Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, IAEA Laboratories, A-2444 Seibersdorf, Austria
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  • JORGE L. CLADERA,

    1. Laboratorio de Genética de Insectos de Importancia Económica, IGEAF, INTA Castelar, Los Reseros y Las Cabañas, Castelar (1712), Buenos Aires, Argentina
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  • PETER TEAL,

    1. Center for Medical, Agricultural, and Veterinary Entomology, US Department of Agriculture Agricultural Research Service, 1600–1700 SW 23rd Drive, Gainesville, FL, USA
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  • PANAGIOTIS SAPOUNTZIS,

    1. Department of Environmental and Natural Resources Management, University of Ioannina, 2 Seferi Street, 30100 Agrinio, Greece
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  • KOSTAS BOURTZIS,

    1. Department of Environmental and Natural Resources Management, University of Ioannina, 2 Seferi Street, 30100 Agrinio, Greece
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  • ANTIGONE ZACHAROPOULOU,

    1. Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, IAEA Laboratories, A-2444 Seibersdorf, Austria
    2. Department of Biology, University of Patras, Patras 26500, Greece
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  • ALAN S. ROBINSON

    Corresponding author
    1. Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, IAEA Laboratories, A-2444 Seibersdorf, Austria
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E-mail: a.s.robinson@iaea.org

Abstract

It has long been proposed that the nominal species Anastrepha fraterculus is a species complex and earlier studies showed high levels of pre-zygotic isolation between two laboratory strains from Argentina and Peru. Further experiments were carried out on the same populations and on their reciprocal hybrids, including pre- and post-zygotic isolation studies, pheromone analysis, and mitotic and polytene chromosome analysis. A high level of pre-zygotic isolation had been maintained between the parental strains despite 3 years of laboratory rearing under identical conditions. The level of pre-zygotic isolation was reduced in matings with hybrids. There were also differences in other components of mating behaviour. There were quantitative and qualitative differences in the sex pheromone of the two strains with the hybrids producing a mixture. The pre-zygotic isolation barriers were complemented by high levels of post-zygotic inviability and sex ratio distortion, most likely not due to Wolbachia, although there was evidence of some cytoplasmic factor involved in sex ratio distortion. Analysis of polytene chromosomes revealed a high level of asynapsis in the hybrids, together with karyotypic differences between the parental strains. The combined results of the present study indicate that these two strains belong to different biological entities within the proposed A. fraterculus complex. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 152–165.

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