Open AccessCytological evidence for a complex of species within the taxon Bactrocera tau (Diptera: Tephritidae) in Thailand
Author(s) -
BAIMAI V.,
PHINCHONGSAKULDIT J.,
SUMRANDEE C.,
TIGVATTANAT S.
Publication year - 2000
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2000.tb01213.x
Subject(s) - biology , tephritidae , bactrocera , karyotype , species complex , reproductive isolation , taxon , heterochromatin , b chromosome , zoology , host (biology) , ploidy , autosome , botany , chromosome , evolutionary biology , genetics , population , pest analysis , demography , sociology , gene , phylogenetic tree
Analysis of mitotic karyotypes of wild specimens of larvae of the Bactrocera tea‐like fruit flies (Diptera: Tephritidae) in Thailand has revealed seven distinct chromosome forms, based on the amount and distribution of heterochromatin in sex chromosomes and autosomes. Such cytological differences are perfecdy correlated with morphological observations and molecular genetics data. These findings clearly suggest that B. tau is a cluster of at least seven closely related species temporarily designated as species A (= B. tau) , B, C, D, E, F and G. On die basis of the gross quantity of heterochromatin accumulation in the genome, three groups of mitotic karyotypes can be recognized. Group 1 comprises species A and E. Species E specifically occurs only in fruits of Strychnos thorelii while species A attacks many kinds of host plants. Group 2 contains species B, F and G. Species B has been found only in Siphonodon celastrineus fruit, whereas species F and G attack die same host species, the medically important plant, Hydnocarpus anthelminthicus , albeit in different localities. Group 3 includes species C and D, each of which comprises larger amounts of pericentric heterochromatin in all chromosomes than die other two groups. Hence, diese two species are cytologically remote from those of groups 1 and 2. Species C and D occur allopatrically but they attack the same host plant species, Momordica cochinchinensis. Thus, genetic differentiation at the chromosomal level to specific host plant species and geographic isolation seem to play an important role in speciation of members of the B. tau complex.