Karyotype and male reproductive system in Arachnocoris trinitatus Bergroth. First data on the tribe Arachnocorini (Heteroptera: Nabidae: Nabinae). Folia Biologica (Kraków)



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Folia biologica (Kraków)


As an extension of the ongoing cytogenetic studies of the bug family Nabidae (Heteroptera:Cimicomorpha), the first evidence for the tribe Arachnocorini (the subfamily Nabinae), with reference to the Trinidad endemic, Arachnocoris trinitatus Bergroth, is provided. This is an attempt to gain a better insight into the evolution, systematics and within-family relationships of the family Nabidae. The studies were conducted using a number of cytogenetic techniques. The male karyotype (chromosome number and size; sex chromosome system; NOR location; C-heterochromatin amount, distribution and characterization in terms of the presence of AT-rich and GC-rich DNA), and male meiosis with particular emphasis on the behavior of the sex chromosomes in metaphase II are described. Also investigated are the male and female internal reproductive organs with special reference to the number of follicles in a testis and the number of ovarioles in an ovary. A. trinitatus was found to display a number of characters differentiating it from all hitherto studied nabid species placed in the tribe Nabini of the subfamily Nabinae, and in the tribe Prostemmatini of the subfamily Prostemmatinae. Among these characters are chromosome number 2n = 12 (10 + XY), the lowest within the family, nucleolus organizer regions (NORs)situated on the autosomes rather than on the sex chromosomes as is the case in other nabid species, and testes composed of 3 follicles but not of 7 as in other nabids. All the data obtained suggest many transformations during the evolution of A. trinitatus.


(for V. G. Kuznetsova) by the Russian Foundation for Basic Research, Grant No. 05-04-48387, the program of the Presidium of the Russian Academy of Sciences “Dynamics of Gene Pools in Animals, Plants and Man”, the program of the St. Petersburg Scientific Centre of the Russian Academy of Sciences “The Divergence of Genetic Material in the Evolution of Phylogenetic Branches of Eukaryotes”, and (for S. Grozeva) by the National Science Fund, Bulgarian Ministry of Education and Science, Grant B-1304. The study was also supported by the Russian Academy of Sciences, the Bulgarian Academy of Sciences and the Academy of Finland.

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Heteroptera, Nabidae, Arachnocorini, Arachnocoris trinitatus, karyotype, C-heterochromatin, NOR, CMA3, DAPI, meiosis, internal reproductive organs, evolution, karyosystematics