Abstract
BackgroundThe Bactrocera dorsalis species complex currently harbors approximately 90 different members. The species complex has undergone many revisions in the past decades, and there is still an ongoing debate about the species limits. The availability of a variety of tools and approaches, such as molecular-genomic and cytogenetic analyses, are expected to shed light on the rather complicated issues of species complexes and incipient speciation. The clarification of genetic relationships among the different members of this complex is a prerequisite for the rational application of sterile insect technique (SIT) approaches for population control.ResultsColonies established in the Insect Pest Control Laboratory (IPCL) (Seibersdorf, Vienna), representing five of the main economic important members of the Bactrocera dorsalis complex were cytologically characterized. The taxa under study were B. dorsalis s.s., B. philippinensis, B. papayae, B. invadens and B. carambolae. Mitotic and polytene chromosome analyses did not reveal any chromosomal characteristics that could be used to distinguish between the investigated members of the B. dorsalis complex. Therefore, their polytene chromosomes can be regarded as homosequential with the reference maps of B. dorsalis s.s.. In situ hybridization of six genes further supported the proposed homosequentiallity of the chromosomes of these specific members of the complex.ConclusionsThe present analysis supports that the polytene chromosomes of the five taxa under study are homosequential. Therefore, the use of the available polytene chromosome maps for B. dorsalis s.s. as reference maps for all these five biological entities is proposed. Present data provide important insight in the genetic relationships among the different members of the B. dorsalis complex, and, along with other studies in the field, can facilitate SIT applications targeting this complex. Moreover, the availability of 'universal' reference polytene chromosome maps for members of the complex, along with the documented application of in situ hybridization, can facilitate ongoing and future genome projects in this complex.
Highlights
The Bactrocera dorsalis species complex currently harbors approximately 90 different members
Polytene chromosomes derived from two F1 bidirectional hybrids (B. dorsalis s.s. × B. invadens and B. dorsalis s.s. × B. carambolae) were analyzed, aiming at the detection of fixed chromosomal rearrangements among the parental colonies. We focused on these hybrids since: a) B. invadens is the only member of the complex originating from Africa, and its current recognition as a distinct species within the complex has severe quarantine consequences and b) B. carambolae is considered to be more clearly differentiated from the other four members of the complex [10,11,16]
B. dorsalis complex strains Colonies representing the five economic important members of the complex currently established at the Insect Pest Control Laboratory (IPCL) were used
Summary
The Bactrocera dorsalis species complex currently harbors approximately 90 different members. The Bactrocera dorsalis complex species is a group of true fruit flies belonging to Tephritidae, with great economic importance. Following the most recent taxonomic revisions, this complex is currently harboring approximately 90 morphological similar taxa [1,2]. Eight are considered as economic important pests [2], including among others B. dorsalis s.s., B. philippinensis, B. papayae and B. carambolae. Research performed by different laboratories points to a possible overestimation in the number of discrete taxa in the complex and the need of another taxonomic revision to incorporate the synonymic status of different species. Drew and Romig [1] have synonymized B. papayae with B. philippinensis; there is an ongoing debate about the species status of other important pests of the complex
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
