Genome size of the northern walkingstick, Diapheromera femorata (Phasmida: Heteronemiidae)

Abstract

The haploid genome size (C value) of the northern walkingstick, Diapheromera femorata (Say), was estimated to be 1C = 2.55 pg using Feulgen image-analysis densitometry of haemocyte and sperm nuclei. This relatively large genome is similar in size to the genomes of the few other phasmids studied so far, and is consistent with hypotheses regarding an upper limit to the size of many insect genomes imposed by the process of metamorphosis, which is relaxed among hemimetabolous orders. Comments on sperm morphology in D. femorata are also provided, and another possible relationship between genome size and the organismal phenotype in insects is suggested.Résumé : La taille du génome haploïde (valeur de C) du phasme Diapheromera femorata (Say) a été estimée à 1C = 2,55 pg par analyse densitométrique d'images Feulgen des noyaux des hémocytes et des spermatozoïdes. Cette taille relativement élevée du génome est semblable à celles des génomes de quelques autres phasmides déjà étudiés et s'accorde avec les hypothèses sur la limite supérieure de la taille du génome de plusieurs insectes, limite imposée par le processus de métamorphose qui est moins contraignant chez les ordres d'hémimétaboles. On trouvera ici quelques commentaires sur la morphologie des spermatozoïdes de D. femorata qui soulignent la possibilité d'une relation entre la taille du génome et le phénotype organismique chez les insectes.[Traduit par la Rédaction] 1305 Gregory

C-value estimates for 31 species of ladybird beetles (Coleoptera: Coccinellidae)

“…C‐values were assessed using the Feulgen image analysis densitometry equipment and protocols described in detail by H ardie et al (2002). While most insects, including most beetles, possess elongated spermatozoa (G regory 2002a), those of many coccinellids are particularly long and lightly staining, which greatly complicates their measurement. When possible, sperm were used in comparison to a Drosophila melanogaster (1C=0.18 pg) sperm standard, but in cases where these cells could not be used, haemocytes were analyzed relative to a Tenebrio molitor (1C=0.52 pg) haemocyte standard (Table 1).…”

Genome size variation in lepidopteran insects

“…Genome sizes were estimated by Feulgen image analysis densitometry of spermatozoa (Hardie et al 2002). In most insects, mature sperm are thin and highly elongated and lack a distinct head (Gregory 2002a). Sperm of this type ordinarily form in bundles, which must be dispersed so that individual nuclei can be measured.…”

Biology and ecology of the Northern walkingstick, Diapheromera femorata (Say) (Phasmatodea: Diapheromerinae): A review

“…although other hardwood trees and shrubs are also utilized (Caudell, 1903a; Hutchings, 1920; Wilson, 1971; Wygant, 1950). Past studies of this insect include morphology (Davis, 1923; Hutchings, 1920; Scudder, 1901), hosts (Graham, 1937; Terry, 1972), distribution (Hodson, 1972; Knauer & Giese, 1970), damage (Anonymous, 1887a, 1887b; Butler, 1914; CSLP, 1973; Graham, 1937; Oatman, 1965; Riley, 1879; Terry, 1972), egg structure (Baker & Chandrapatya, 2001; Severin, 1910), hatch mechanism (Severin & Severin, 1911a), adult cuticular lipids (Warthen et al., 1981), complete genome (Gregory, 2002), life history (Severin & Severin, 1911b; Wilson, 1971), environmental factors (Giese & Knauer, 1977; Severin & Severin, 1910, 1913), ecology (Giese & Knauer, 1977) and natural enemies (Milliron, 1950; Walton, 1914). The aim of this review is to provide a synopsis on the distribution, morphology, host species, damage, biology, natural enemies and management for this insect in reference to other notable species in the United States and economically important species around the world.…”