Geographic Variation in Meiotic Instability in <I>Eucheira socialis</I> (Lepidoptera: Pieridae)

Chromosome Number of the Monarch Butterfly, Danaus plexippus (Linnaeus 1758) and the Danainae

“…Lepidopteran chromosomes are holokinetic, i.e. kinetochores are located along the length of the chromosome, rather than concentrated at one location, which is thought to allow spindle fibers to attach at multiple locations along a chromosome and therefore increase the rate of fission (White 1973), resulting in multiple chromosome numbers within genera, species, and even individuals (Robinson 1971;Underwood et al 2005;Dincă et al 2011;Šíchová et al 2015). This feature, known as disploidy, occurs throughout the Lepidoptera and is present in the Danaini (Maeki 1961;Brown et al 2004).…”

“…To establish karyotypes for D. plexippus from Kansas I prepared chromosome squashes following the protocol used by Underwood et al 2005. Briefly, I removed the testes from 5th instar larvae and placed them into fixative.…”

“…As such, there can be significant variation in chromosome number within a Family, Genus or species. For example Eucheira socialis Westwood 1834 (Lepidoptera: Pieridae) exhibits a haploid chromosome count range from n = 24 to n = 39 (Underwood et al 2005), and Eunica malvina Bates 1864 (Lepidoptera: Nymphalidae) has a range of n = 14 o n = 31 (Brown et al 2007).While there are clearly species that exhibit a range of haploid numbers, it appears there is strong selection to maintain a particular haploid number of chromosomes that vary by taxa (White 1978;Ahola et al 2014).…”