THE DESOXYRIBONUCLEIC ACID CONTENT OF THE NUCLEUS AS A CYTOTAXONOMIC CHARACTER IN MANTIDS (ORTHOPTERA : MANTOIDEA)

Abstract

The relative amt. of DNA per spermatid nucleus has been detd. by micro-photometry in 8 spp. of mantids, and the results are discussed in relation to their cytology and the ctyotaxonomic problems they present. The mantids studied are the following: Subfamily Liturgousinae[long dash]Liturgousa maya, L. actuosa, L. cursor; Subfamily Choeradodinae-Choeradodis rhombicollis; Subfamily Manteinae[long dash]Tauromantis championi, Stagmomantis Carolina S. heterogamia; and Subfamily Pseudomiopteriginae[long dash]Pseudomiopteryx infuscata. Of the 3 closely similar spp. of Liturgousa tested, L. maya with 16 autosomes and L. cursor with 32 have the same content of DNA in the spermatid nucleus, confirming the cytological evidence that no polyploid relation exists between them. The greater diam. and greater total length of metaphase chromosomes in maya as compared with cursor remain unexplained. Liturgousa actuosa has approx. one and one-half times the amt. of spermatid DNA as maya and cursor[long dash]in marked disagreement with the cytological evidence for an intermediate position. Tauromantis championi and the two spp. of Stagmomantis. are uniform in DNA spermatid values, as in karyotypes. For Choeradodis no reliable sp. constant in nuclear DNA could be detd., due to abnormalities in the material, but a value not exceeding that of the Manteinae is indicated; this is in harmony with the cytological evidence. The ratio of DNA per spermatid nucleus in Pseudomiopteryx infuscata to that in Stagmomantis heterogamia is 0.47; the ratio in total length of chromosomes at the preceding metaphase is 0.39. The implications of these findings for the hypothesis that polyploidy has been involved in the evolution of high and low number karyotypes among mantids are considered.