A new species of the genus Rhaphidosoma Amyot et Serville, 1843 (Heteroptera, Reduviidae), with data on its chromosome complement

Abstract

A new species, Rhaphidosoma paganicumsp. nov. (Heteroptera: Reduviidae: Harpactorinae: Rhaphidosomatini), is described from the Dry Zone of Myanmar. It is the fifth species of Rhaphidosoma Amyot et Serville, 1843, known from the Oriental Region, and the first record of the genus for Myanmar and Indochina. The structure of the external and internal terminalia of the male and female is described and illustrated in detail. The completely inflated endosoma is described for the first time in reduviids. The complex structure of the ductus seminis is shown; it terminates with a voluminous seminal chamber which opens with a wide secondary gonopore and may be a place where spermatophores are formed. The new species is compared with all congeners from the Oriental Region and Western Asia. It is characterised by the absence of distinct tubercles on the abdominal tergites of the male, the presence only two long tubercles and small rounded ones on the abdominal tergites VII and VI, respectively, in the female, the presence of short fore wing vestiges which are completely hidden under longer fore wing vestiges, and other characters. In addition to the morphological description, an account is given of the male karyotype and the structure of testes of Rh. paganicumsp. nov. and another species of Harpactorinae, Polididus armatissimus Stål, 1859 (tribe Harpactorini). It was found that Rh. paganicumsp. nov. has a karyotype comprising 12 pairs of autosomes and a multiple sex chromosome system (2n♂=24A+X1X2X3Y), whereas P. armatissimus has a karyotype comprising five pairs of autosomes and a simple sex chromosome system (2n♂=10A+XY). The males of these species were found to have seven and nine follicles per testis, respectively. FISH mapping of 18S ribosomal DNA (major rDNA) revealed hybridisation signals on two of the four sex chromosomes (Y and one of the Xs) in Rh. paganicumsp. nov. and on the largest pair of autosomes in P. armatissimus. The presence of the canonical “insect” (TTAGG)n telomeric repeat was detected in the chromosomes of both species. This is the first application of FISH in the tribe Raphidosomatini and in the genus Polididus Stål, 1858.

Comparative Cytogenetics of Lace Bugs (Tingidae, Heteroptera): New Data and a Brief Overview

“…This pattern seems to predominate in Heteroptera, being found in half of the species studied, and occurs in species differing in chromosome numbers and sex chromosome systems (reviewed in [ 31 ]). Specifically, it predominates in the particular families where more data have been accumulated, for example, Reduviidae (e.g., [ 47 , 50 , 51 ]), Pentatomidae, and Coreidae (e.g., [ 52 , 53 ]). This allows it to be considered as the ancestral condition in Heteroptera as a whole [ 47 , 50 ].…”

“…For example, differences in 45S rDNA positions seem to exist between two largest and most extensively studied “monocentric” insect groups, Coleoptera and Orthoptera: beetles show a preference for the distal position of 45S rDNA loci, whereas in orthopterans (at least in grasshoppers and crickets), a pericentromeric position is preferred, and terminal locations occur only in exceptional cases [ 64 ]. The majority of 45S sites mapped to date in heteropteran species show a terminal localization [ 31 , 53 ]. In lace bugs, on the contrary, rDNA loci seem to show a tendency to localize in the interstitial position ([ 29 ], present paper), although in some species they were placed closer to the ends of chromosomes ([ 26 ], present paper).…”

A synopsis of the numbers of testicular follicles and ovarioles in true bugs (Heteroptera, Hemiptera) – sixty-five years of progress after J. Pendergrast’s review

“…were tentatively given. In P. armatissimus , the structure of the testis was shown to be complex: the follicles form two groups, one consisting of seven long and wide follicles and the other consisting of two smaller follicles ( Gapon et al 2021 ).…”

“…The testis comprising seven follicles are suggested to be an ancestral trait for the Reduviidae ( Gapon et al 2021 ). This testis structure has been described for Lisarda vandenplasi Schouteden, 1931 ( Salyavatinae ), eight species of the subfamily Reduviinae , 19 species of the Harpactorinae as well as for Phymata sp.…”

Expanding the Chromosomal Evolution Understanding of Lygaeioid True Bugs (Lygaeoidea, Pentatomomorpha, Heteroptera) by Classical and Molecular Cytogenetic Analysis

“…In several species, FISH-based karyotyping, specifically rDNA mapping, has pointed to chromosomal differences between species with similar karyotypes [ 22 , 35 ]. In recent years, studies using FISH, mainly for analyzing the 18S region of the major 45S rDNA, have become very popular in true bugs (reviewed in [ 24 , 25 , 36 , 37 , 38 , 39 ] and references therein). However, such studies have rarely been attempted in the Lygaeoidea.…”