Research Article |
Corresponding author: Renata Da Rosa ( renata-darosa@uel.br ) Academic editor: Natalia Golub
© 2016 Angélica Nunes Tiepo, Larissa Forim Pezenti, Thayná Bisson Ferraz Lopes, Carlos Roberto Maximiano da Silva, Jaqueline Fernanda Dionísio, José Antônio Marin Fernandes, Renata Da Rosa.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Tiepo AN, Pezenti LF, Lopes TBF, da Silva CRM, Dionisio JF, Fernandes JAM, Da Rosa R (2016) Analysis of the karyotype structure in Ricolla quadrispinosa (Linneus, 1767): inferences about the chromosomal evolution of the tribes of Harpactorinae (Heteroptera, Reduviidae). Comparative Cytogenetics 10(4): 719-729. https://doi.org/10.3897/CompCytogen.v10i4.10392
|
The subfamily Harpactorinae is composed of six tribes. Phylogenetic studies bring together some of Harpactorinae tribes, but by and large the data on evolutionary relationships of the subfamily are scarce. Chromosome studies are of great importance for understanding the systematics of different groups of insects. For Harpactorinae, these studies are restricted to some subfamilies and involved only conventional chromosome analysis. This work analyzed cytogenetically Ricolla quadrispinosa (Linneus, 1767). The chromosome number was determined as 2n = 24 + X1X2Y in males. In metaphase II the autosomal chromosomes were organized in a ring with the pseudo-trivalent of sex chromosomes in its center. After C-banding followed by staining with DAPI, AT-rich blocks in autosomes were observed and the negatively heteropycnotic sex chromosomes. The data obtained, together with existing data for other species of the group, indicated that different chromosomal rearrangements are involved in the evolution of the species. In addition, a proposal of karyotype evolution for the subfamily, based on existing phylogenetic studies for the group is presented.
holokinetic chromosomes, speciation, DAPI, heterochromatin, reproductive isolation, chromosomal rearrangements
Reduviidae are the largest family of predatory insects of the suborder Heteroptera, consisting of approximately 7000 species (
In Harpactorinae cytogenetic studies are restricted to only three of the six tribes: Apiomerini, Dicrotelini, and Harpactorini (Table
Tribe | Species | Diploid number (♂)* | Reference |
---|---|---|---|
Apiomerini | Apiomerus lanipes | 22A+XY |
|
Apiomerus crassipes | 22A+XY |
|
|
Apiomerus flaviventris | 22A+XY |
|
|
Apiomerus spissipes | 22A+XY |
|
|
Apiomerus sp. | 22A+XY |
|
|
Heniartes huacapistana | 22A+XY |
|
|
Dicrotelini | Henricohahnia typica | 24A+X1X2X3Y |
|
Harpactorini | Acholla ampliata | 24A+X1X2X3Y |
|
Acholla multispinosus | 20A+X1X2X3X4X5Y |
|
|
Arilus cristatus | 22A+X1X2X3Y |
|
|
Coranus fuscipennis | 24A+X1X2Y |
|
|
Coranus sp. | 24A+X1X2Y |
|
|
Cosmoclopius nigroannulatus | 24A+X1X2X3Y |
|
|
Cosmoclopius poecilus | 24A+X1X2X3Y |
|
|
Cydnocoris crocatus | 24A+X1X2Y |
|
|
Euagoras erythrocephala | 24A+X1X2Y |
|
|
Euagoras plagiatos | 24A+X1X2Y |
|
|
Fitchia spinulosa | 24A+ X1X2Y |
|
|
Harpactor fuscipes | 24A+X1X2X3Y |
|
|
Irantha armipes | 24A+X1X2X3Y |
|
|
Lophocephala guerini | 24A+X1X2Y |
|
|
Montina confusa | 12+XY |
|
|
Polididus armatissimus | 10A+XY |
|
|
Polididus sp. | 10A+XY |
|
|
Pselliopus cinctus | 24A+ X1X2X3Y |
|
|
Repipta flavicans | 18A+XY |
|
|
Repipta taurus | 24A+ X1X2X3Y |
|
|
Ricolla quadrispinosa | 24+X1X2Y | Present study | |
Rhynocoris costalis | 24A+X1X2X3Y |
|
|
Rhynocoris fusicipes | 24A+ X1X2X3Y |
|
|
Rhynocoris kumarii | 24A+X1X2X3Y |
|
|
Rhynocoris marginatus | 24A+ X1X2X3Y |
|
|
Rhynocoris sp. | 24A+X1X2X3Y |
|
|
Rocconota annulicornis | 24A+X1X2Y |
|
|
Sinea complexa | 24A+X1X2X3Y |
|
|
Sinea confusa | 24A+X1X2X3Y |
|
|
Sinea rileyi | 24A+X1X2X3 X4X5Y |
|
|
Sinea spinipes | 24A+X1X2X3Y |
|
|
Sphedanolestes himalayensis | 24A+X1X2X3Y |
|
|
Sycanus collaris | 24A+X1X2X3Y |
|
|
Sycanus croceovittatus | 24A+X1X2X3Y |
|
|
Sycanus sp. | 24A+X1X2X3Y |
|
|
Velinus nodipes | 24A+X1X2X3Y |
|
|
Velinus annulatus | 24A+X1X2X3Y |
|
|
Vesbius purpureus | 24A+XY |
|
|
Zelus exsanguis | 24A+XY |
|
|
Zelus sp. close to Z. leucogrammus | 24A+XY |
|
|
Zelus laticornis | 24A+XY |
|
Evolutionary relationships related to karyotype changes are poorly known for Harpactorinae, and the majority of karyological reports in Harpactorinae are restricted to conventional analysis without the application of banding techniques (
Fifteen male specimens of R. quadrispinosa were collected from Iguaçu National Park - Foz do Iguaçu - Brazil - 25°37'40.67"S; 54°27'45.29"W (DDM). Each individual was identified and deposited at the Federal University of Pará (UFPA).
The gonads of the adult specimens were dissected in physiological solution for insects (7.5g NaCl, 2.38g Na2HPO4, 2.72g KH2PO4 in 1L of distilled water). The testes were treated with tap water for 3 min and fixed in methanol:acetic acid (3:1) for 30 min. Chromosome preparations were performed through cellular suspension by maceration in a drop of 60% acetic acid, with each gonad previously treated with 45% acetic acid. These preparations were submitted to conventional staining with Giemsa 3% and also to chromosome banding techniques. Chromosome measurements were carried out using the computer application MicroMeasure version 3.2 (
The distribution of heterochromatin was analyzed by Giemsa C-banding according to
The males of R. quadrispinosa presented 2n = 24 + X1X2Y. In metaphase II, the autosomes are arranged in ring while the three sex chromosomes form a pseudo-trivalent in the center (Fig.
Meiocytes of Ricolla quadrispinosa. A, B conventional staining: metaphase II C conventional staining: interphase nucleus D Giemsa C-banding: metaphase II EDAPI staining: metaphase II. Sex chromosomes indicated by arrows. Interstitial heterochromatic block indicated by asterisk. Scale bar: 5µm.
The fluorochrome staining with DAPI performed after the C-banding revealed several AT-rich blocks in the autosomes, which were located in both the terminal and interstitial regions of the autosomes while the sex chromosomes were shown to be negatively heteropycnotic (Fig.
The number of autosomes observed in R. quadrispinosa (24) was similar to that revealed in the most species of the tribe Harpactorini (Table
Within Harpactorinae, there is a very striking karyotype conservation in the Apiomerini tribe, where all species studied so far have presented 2n = 22 + XY (Table
According to
In the Harpactorini, twenty-one species present 2n = 24 + X1X2X3Y and 9 species present 2n = 24 + X1X2Y (Table
For Dicrotelini, the only species have been cytogenetically studied, Henricohahnia typical Breddin, 1900 with 2n = 28 (
Even taking into account the phylogenetic studies for the group proposed by
Chromosomal evolution in Apiomerini and Harpactorini. Evolutionary events marked by caps: A fusion of autosomes B fusion of autosomes C fission of autosomes D fusion of autosomes E fission of sex chromosomes F fission of sex chromosomes. Chromosomal formulae represent the diploid number. The tribe Dicrotelini was not included in scheme because only one species has been studied cytogenetically in this tribe.
Another chromosomal alteration, the fission of autosomal chromosomes (C event) would have led to a new branch within the Harpactorini, originating 2n = 24 + XY (Zelus Fabricius, 1803 and Vesbius Stål, 1866 species) (Table
The multiple sex systems would have arisen by the fission of the X chromosomes of the ancestral XY system (event E) to give the karyotype 2n = 24 + X1X2Y, observed in nine species of the tribe (Table
In addition to differences in the number of autosomes and sex chromosomes, in R. quadrispinosa the sex chromosomes are presented as negatively heteropycnotic. Also in metaphase II it is possible to notice several AT rich blocks occupying the terminal and, rarely, interstitial regions of the autosomes. Different patterns of heterochromatin have been reported in other 5 Harpactorinae species (
Considering the influence of the chromosomal rearrangements in the speciation processes, particularly those involved in the differentiation of sex chromosomes, we can suggest that these alterations were fundamental as mechanisms of pre-zygotic reproductive isolation. It is probable that these chromosomal alterations caused the separation of groups, as different species are observed in the same geographical region, leading to a process of sympatric speciation.
The authors are grateful to the National Iguaçu Park staff members for their technical assistance; to Edson Mendes Francisco for his help with the sample collection. This work was supported by CNPq, Fundação Araucária and FAEPE/UEL-PUBLIC 2016. The researchers received permission from the Instituto Chico Mendes de Conservação da Biodiversidade – ICMBio to collect specimens.