THE SYSTEMATICS AND KARYOTYPE OF LABIDURA TRUNCATA KIRBY, 1903 (DERMAPTERA: LABIDURIDAE)

Abstract

Systematic and in particular cytogenetic criteria show that the species Labidura truncata Kirby, 1903 should be re-erected. The karyotype was found to be 2nd = I0 (4AA + XY),The systematic history of the members of the genus Labidura Leach, 1815 is reviewed by Brindle (1966), with particular attention to the confused situation concerning Labidura riparia (Pallas 1773). Much of this confusion has undoubtedly resulted from the conviction of increasing numbers of authors that L. riparia (originally described from W. Siberia) is a very variable cosmopolitan species. Synonymic lists, discussions of the validity of systematically significant characters and of the relationships of members of the L. riparia complex are given by Kirby (1903: 63; 1904: 9), Burr (191 1: 36), Bey-Bienko (1936: 101) and Brindle (1966: 243, 257, 259). The last author points out that the male genitalia of specimens from different parts of the world are remarkably similar. His figures show that there are only very slight differences in the apices of the lateral lobes.On the basis of external characters there seems no doubt that Labidura truncata is a distinct form. Kirby (1903) gives as diagnostic characters (other than colouration): the absence of paired teeth on the caudal margin of the posterior tergite between the bases of the forceps and the presence of a preapical tooth (of variable size) on the inner margin of each 'blade of the forceps of the male, the constancy of which is pointed out by Hincks (1954). A study by one of us (E.T.G.) of several large collections from all over Australia has shown both of these to be particularly constant characters. Colouration and the degree of development of the tegmina and wings are variable. Although the female genitalia are not used for diagnostic purposes in the Labiduridae, differences between these organs in specimens in European collections labelled L. riparia and in L. truncata have been observed (E.T.G.). This also points to a separation between the two forms.Below are set out the more important elements of the synonymy. Labidura truncata Kirby, 1903Lahiduru rruncata Kirby, 1903: 67. Kirby, 1904: 11. Burr, 1908 fig. 7. Burr, 1911: 37. Brindle.Ld>iditrcr ripariu geogr. race rruncu/u Kirby, 1903. Burr. 1910. Ld)idirra ripwio /ritncara Kirby, 1903. Hebard, 1933: 147. Hincks. 1954: 8. Giles. 1964: 1109 A relatively uniform karyotype was found in material of both sexes of Labidura truncatu from near Perth and Eucla, W.A.; Wyreema, near Toowoomba, Qld and from Lake Boga, Yarrawonga and many localities near Melbourne, Vic. It can therefore be assumed that the description which follows would apply generally to the cytology of the species throughout Australia.

Interspersed distribution patterns of C-bands and satellite DNA in the holocentric chromosomes of Luzula flaccida (Juncaceae)

“…The telomeric and interstitial blocks of heterochromatin visible during early meiotic prophase of the earwig Labidura truncata were no longer discernible in meiotic metaphase preparations (Giles & Webb, 1972). Similarly, Musich (1973) reported the presence of interstitial and telomeric constitutive heterochromatin throughout meiotic prophase autosomes of the milkweed bug Oncopeltus fasciatus, however these C-bands were not discernible in the darkly-stained metaphase chromosomes.…”

Heterochromatin differentiation in holocentric chromosomes of Rhynchospora (Cyperaceae)

“…Thus, in prophase and prometaphase the band number was much larger than in metaphase. A similar situation was described for insect holocentric chromosomes (see Giles and Webb, 1972;Manicardi et al, 1991;Manicardi and Gautam, 1994).…”

Karyotype and C-banding analysis of the common seaside earwig, Anisolabis maritima (Bonelli) (Anisolabididae, Dermaptera).

“…Labiduridae; 10 chromosomes (8AA+XY : Labidura truneat~a, Giles and Webb, 1972), 12 chromosomes (1OAA+XY : L, riparia, Ortiz, 1969. L, bengalensis, Mittal et al, 1974.…”