Corresponding author: Valentina G. Kuznetsova (
Academic editor: Pavel Štys
The Cimicomorpha is one of the largest and highly diversified infraorders of the
The
The cytogenetics of the
Since Ueshima’s publication a large body of new cytogenetic data on the
The
Autosome numbers’ range in
Distribution of sex chromosome systems in
Holokinetic chromosomes (sometimes designated as holocentric) occur in certain scattered groups of plants and animals, being particularly widespread in insects, including the
Despite an important role of chromosomal change in the evolution and diversification of many groups of organisms (
Chromosome numbers have been published for approximately 465 species (180 genera) of cimicomorphan true bugs, including many of the higher taxonomic categories within the infraorder (
However, the commonest chromosome number needs not to be plesiomorphic in a taxon. A good example comes from the family
Considering the lack of a centromere, holokinetic chromosomes exhibit a very limited number of characters that can be used as markers. That is why, in spite of recent progress in developing of different staining techniques, chromosomal rearrangements not changing the number of chromosomes, such as inversions and reciprocal translocations, have been very rarely reported in the
The term “mchromosomes” has been introduced by
In Ueshima’s review (
The currently available data suggest that the presence or absence of mchromosomes represents a quite stable character at higher taxonomic levels in the
Genetic sex determination is predominant in insects and is often accompanied by the presence of a heteromorphic chromosome pair in one sex. The true bugs share male heterogamety with the great majority of other insects. Within the
The question as to whether the common ancestor of all
On the other hand, (
The most basal heteropteran infraorders are considered to be
The existence of Ychromosome in the
In the
Compared to other
Bchromosomes, also known as supernumerary, accessory, or extra chromosomes, are dispensable elements which do not recombine with other chromosomes (the Achromosomes) of the standard complement and follow their own evolutionary pathway (
It is common knowledge that in meiosis, chiasmata (the points of genetic crossingover) are formed uniting homologous chromosomes together until their separation in the reductional division. However in some animal groups chiasma formation is replaced by other, achiasmate means. When meiosis is achiasmate, at early prophase I one can see the conventional sequence of leptotene, zygotene and pachytene stages. However, no chiasmata are formed and hence no diplotene or diakinesis stages can be recognized. Typically, achiasmate meiosis is restricted to the heterogametic sex of a species. In most heteropteran males, autosomal bivalents are chiasmate whereas sex chromosomes have no chiasmata, however in a number of families male meiosis is completely achiasmate (
Multiple origins of achiasmate meiosis in
The multiple origin of achiasmate meiosis is well in accordance with the observations on the divergence in its cytological properties. The most common type of achiasmate meiosis is the socalled
In the
Additionally, in the
In general, during the first division of meiosis the chromosomes reduce in number (reductional division), whereas during the second division the chromatids separate (equational division), and this pattern is named “prereduction” (
In most
Another characteristic feature is the configuration of metaphase I and metaphase II plates, which pattern seems to show speciesspecific variation in the
For technical reasons, most research on heteropteran chromosomes has used males and as a consequence, there is very little evidence on meiosis in females.
One of the mirid species,
In general, cytogenetic studies of the
In the last few decades, the ability to identify chromosomes has been markedly improved by the development of molecular cytogenetic technologies such as fluorescence
A potential ﬁeld of interest concerns the molecular composition of telomeres, which is totally unknown in the true bugs. Telomeres are terminal regions of chromosomes that protect chromosomes from destruction and stabilize their structure (
Chromosome numbers and sex chromosome systems in











24+XY 


28+X0  
32+XY 


18+XY 


14+XY 


26+2m+XY  
20+X_{1}X_{2}X_{3}X_{4}X_{5}Y (1)  
n=16 (1)  
22+XY  
22+X_{1}X_{2}X_{3}Y  
24+X_{1}X_{2}X_{3}Y 


24+X_{1}X_{2}Y 


24+X_{1}X_{2}Y 


24+X_{1}X_{2}Y 


24+X_{1}X_{2}X_{3}Y  
22+XY 


24+X_{1}X_{2}Y 


10+XY (1) 


10+XY  
12+XY  
24+X_{1}X_{2}X_{3}Y  
24+X_{1}X_{2}X_{3}Y  
24+X_{1}X_{2}Y 


24+X_{1}X_{2}X_{3}Y (5) 20+X_{1}X_{2}X_{3}X_{4}X_{5}Y (1)  
24+X_{1}X_{2}X_{3}Y  
24+X_{1}X_{2}X_{3}Y  
24+XY  
24+XY 


20+XY 


20+XY (1) 20+X_{1}X_{2}Y (2) 


20+X_{1}X_{2}Y 


26+XY 


26+XY 


26+XY  
24+X_{1}X_{2}X_{3}X_{4}Y 


20+XY (1) 26+XY (1)  
24+XY 


20+X_{1}X_{2}Y (4) 20+X_{1}X_{2}X_{3}Y (1) 22+X_{1}X_{2}X_{3}Y (2)  
20+X_{1}X_{2}X_{3}X_{4}Y 


22+XY (1) 22+X_{1}X_{2}Y (1) 


20+X_{1}X_{2}X_{3}X_{4}Y 


20+X_{1}X_{2}Y 


20+XY 


20+X_{1}X_{2}Y 


20+X_{1}X_{2}Y  
18+X_{1}X_{2}Y (1) 20+X_{1}X_{2}Y (7)  
18+X_{1}X_{2}Y (1)  
20+XY (1) 


20+XY  
18+X_{1}X_{2}Y (1) 20+XY (25) 20+X_{1}X_{2}Y (21) 20+X_{1}X_{2}X_{3}Y (2)  
20+X_{1}X_{2}Y  
22+X_{1}X_{2}Y  


12+XY 


12+XY  


22+XY 




32+XY 


32+XY 


32+XX (♀♀) 


36+XY (1) 40+XY (1) 44+XY(1) 44+X_{1}X_{2}Y (1) 46+XY (8) 46+2m+X_{1}X_{2}X_{3}Y (1) 46+X_{1}X_{2}Y (1) 46+X_{1}X_{2}X_{3}Y (1)  
26+XY 


16+XY (1) 18+XY (1) 


24+XY (1) 24+X_{1}X_{2}X_{3}Y (1) 26+XY (1)  
32+XY  
26+XY 


32+XY (11) 34+XY (1) 30+2m+XY (2)  
32+XY  
32+XY (1) 34+XY (1)  
20+XY (1) 22+XY (2) 24+XY (1) 26+XY (1)  
12+2m+XO  
30+XY  
2n=28  
26+X_{1}X_{2}0  
32+XY  
32+XY  
32+XY  
30+2m+XY  
32+XY 


32+XY (1)  
30+XY  
32+XY  
12+XY  
30+XY 


32+XY  
32+XY (1)  
28+2m+XY (1) 


30+XY 


32+XY  
30+XY  
32+XY  
32+XY  
32+XY  
32+XY  
32+XY (10)  
32+XY  
32+XY (4)  
n=19?  
30+2m+X0  
32+XY  
30+XY 


32+XY  
30+XY  
32+XY  
12+2m+X0 


30+XY 


22+XY  
32+XY  
32+XY (8) 30+XY (1)  
32+XY  
32+XY  
30+XY  
30+XY (1) 32+XY (1)  
40+XY (1) 


30+XY  
32+XY  
2n=3234  
32+XY  
32+XY  
32+XY  
22+XY 


18+XY (1) 22+XY (3)  
21+ X_{1}X_{2}Y  
32+XY (1)  Grozeva and Simov 2011  
32+XY  
34+X_{1}X_{2}Y  
28+XY  
32+XY  
24+XY  
38+XY  
78+XY  
20+XY (1) 


26+XY 


28+XY  
22+XY (2) 24+XY (1) 26+XY (2) 28+XY (1)  
24+XY  
26+XY  
22+XY  
28+XY  
24+XY  
24+XY  
30+XY  
30+XY  
30+XY  
30+XY  
30+XY  
30+XY  
26+XY (1) 28+XY (1) 


30+XY  
30+XY  
32+XY  Grozeva, 2003  
24+XY (1) 2n=4 (1)** 


30+XY  
32+XY  
30+XY 


30+XY 


32+XY  
30+XY  
30+X0 


26+XY (1) 28+XY (3)  
30+X0 (1) 30+XY (4) 32+XY (1)  
32+XY (1)  
28+XY  
30+XY  
32+XY  
30+XY  
28+XY (3) 30+XY (4)  
2n=8** 


12+X0 (2) 


10+XY  
12+X0  
12+XY 


12+XY 


12+XY 


12+XY 


12+XY  
12+XY  
12+XY  
12+XY  
12+XY  
12+XY 


12+XY 


12+XY 


12+XY 


12+XY  
12+XY 


12+XY  


10+XY  
36+XY  
16+XY  
38+XY  
3236+XY (1)  
32+XY (1)  
30+XY  
16+XY 


16+XY 


16+XY (6)  
16+XY  
18+XY  
32+XY  
16+XY  
32+XY  
16+XY  
16+XY  
16+XY  
16+XY  
16+XY  
26+XY 


26+XY 




28+XY  
22+XY 


30+XY 


22+X_{1}X_{2}Y 


8+XY 


8+XY 10+XY 


36+X_{1}X_{2}Y 


22+XY  
8+XY 


22+XY (1) 36+X_{1}X_{2}Y (1) 


22+XY (1) 24+XY (1) 28+XY (1) 26+X_{1}X_{2}Y (3) 28+X_{1}X_{2}Y (6) 28+X_{1}X_{2}X_{3}Y (6) 28+X_{1}X_{2}X_{3}X_{4}Y (1)  
28+X_{1}X_{2}Y 


36+X_{1}X_{2}Y (4) 36+X_{1}X_{2} X_{3}Y (2) 36+49XY (2)  
32+XY  
10+XY  
28+X_{1}X_{2}Y 


38+X_{1}X_{2}X_{3}Y (1) 38+XY (1) 40+XY (1) 


8+XY 


28+X_{1}X_{2}Y  
28+X_{1}X_{2}Y 


22+XY 


22+XY  
26+XY 


28+XY 


4+XY (1) 10+XY (1) 


6+XY 

* In the paper, only the number of chromosomes (2n/n) is provided, then, the karyotype formula for the species is deduced here from 2n/n, ** But see the text
This study was supported financially by the Russian Foundation for Basic Research (grant 110400734) and programs of the Presidium of the Russian Academy of Sciences “Gene Pools and Genetic Diversity” and “Origin of the Biosphere and Evolution of Geobiological Systems” (for VK) and by National Scientific Fund of Bulgarian Ministry of Education, Youth and Science (TKB1601 and DO02259/08) (for SG), by Russian Academy of Sciences and Bulgarian Academy of Sciences. We express our thanks to Nikolay Simov (NMNH, Sofia) for the valuable advices and help to verify the taxonomic status and latin names of different taxa in Table. We are obliged to anonymous reviewers and particularly to the editor for useful comments on the earlier versions of the manuscript.