Cytogenetic diversity of the European Psylliodes flea-beetles (Coleoptera, Chrysomelidae)

Abstract

Seven European species of Psylliodes flea-beetles have been chromosomally analyzed. The range of diploid numbers in the nine presently known species is wide, from 20 to 36 chromosomes, but most species display 2n=34 and 16+Xyp male karyotypic formula, which is presumably the ancestral value for the genus. Two species, P. dulcamarae and P. affinis, share a neoXY sex chromosome system, have lower diploid numbers than the remaining, and are probably derived by chromosome fusion events. Moreover, the presumed phylogenetic interrelationships based on chromosomes are in good agreement with the female spermathecal groups and with the choice of host-plant. P. dulcamarae shows a B-chromosome polymorphism having three different karyomorphs.

A new contribution to the cytogenetic knowledge of Alticinae (Coleoptera, Chrysomelidae)

“…In the same way, our results in one species of Psylliodes, P. obscuroaeneus with 15+Xy p , 2n=32 meioformula and diploid number respectively, are in agreement with our published data from nine species, whose range in both cytogenetic characters goes from 9+neoXY, 2n=20 to 17+Xy p , 2n=36, as well as with the most common sex‐chromosome system, the “parachute” Xy p , found in seven of those nine analyzed species (S egarra and P etitpierre 1982, 1989).…”

“…They show a wide range of diploid numbers from 2n=8 to 2n=64, as well as a great diversity of male sex‐chromosome systems (S mith and V irkki 1978; P etitpierre et al 1988; V irkki 1988; P etitpierre 1989; S egarra and P etitpierre 1989; V irkki et al 1991; V irkki and S antiago ‐B lay 1998). Some taxa of Alticinae have been studied with a particular detail such as those of the subtribe Oedionychina (S mith and V irkki 1978; V irkki 1988; V irkki and S antiago ‐B lay 1993, 1998) and those of European Longitarsus (S egarra and P etitpierre 1988) and Psylliodes (S egarra and P etitpierre 1989). We report herein the chromosome findings obtained in seven species of flea‐beetles in order to increase the cytogenetic understanding of this subfamily and especially that of the genera Oedionychus, Longitarsus and Psylliodes in particular.…”