Observations of the autumn migration of the rice leaf roller Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) and other moths in eastern China

Abstract

The autumn migration of the rice leaf roller moth, Cnaphalocrocis medinalis Guenée, in eastern China was studied at two sites (one in southern Jiangsu Province and one in northern Jiangxi Province), using radar and aerial netting. It was confirmed that C. medinalis is a high-altitude nocturnal windborne migrant, with large numbers of moths taking-off at dusk and flying continuously for several hours. Migration was post-teneral and the females had immature ovaries. Maximum densities of the moths typically occurred between 250 and 550 m above ground, and layering was intense on some nights. Moth layers often occurred at an altitude where there was a wind-speed maximum. In early September, migrant C. medinalis from southern Jiangsu Province were carried on the winds in an approximately westward direction. However, the winds prevailing in late September and October took migrants from both sites towards the south-west or south. Forward trajectories for C. medinalis and other insects emigrating from northern Jiangxi during October indicated that they were able to reach the tropical rice-growing areas near the south China coast, where year-round breeding would be possible. Incidental observations on the migratory flight of other lepidopteran pests, including Mythimna separata (Walker), Spodoptera litura (Fabricius), Ctenoplusia agnata (Staudinger) and Agrotis ipsilon (Hufnagel) (all Nocturidae), Spoladea recurvalis (Fabricius) and particularly Omiodes indicata (Fabricius) (both Pyralidae) are presented.

Simple rules guide dragonfly migration

“…Major progress has been made in understanding butterfly (Malcolm 1987) and moth migrations on the population level, such as in the oriental armyworm (Mythimna separata; Chen et al 1989), the rice leafroller (Cnaphalocrocis medinalis; Riley et al 1995) or the black cutworm (Agrotis ipsilon; Showers 1997). Dragonfly migration occurs on all continents except Antarctica, and is also a well-documented phenomenon (Russell et al 1998;Corbet 1999;Moskowitz et al 2001;Freeland et al 2003;Artiss 2004).…”

Population genetic structure of the migratory rice leaf roller, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), inferred from the mitochondrial A+T-rich region and nuclear ITS2 sequences

“…During their generations they run rampant, damaging rice leaves; the reduction of output has been reported in a range between 20-60% in China (Riley et al, 1995). Their dispersal capacity is also quite well known; insect monitoring radar has shown that C. medinalis can migrate in large numbers (Riley et al, 1995).…”

“…A substantial amount of research has been conducted on the dispersal of this species in Asia (Miyahara, 1981;Wada et al, 1988;Riley et al, 1995). Although an understanding of the genetic population structures of insect pests may provide us with important biological information, no such studies have yet been conducted on C. medinalis.…”

Visual Orientation and Navigation in Nocturnal Arthropods

“…The nocturnal migrations frequently occur in favourable fast-moving winds [Riley et al, 1983[Riley et al, , 1995Drake, 1985;Feng et al, 2005;Chapman et al, 2008a, b], and can take these insects as far as 650 km in one night [Chapman et al, 2008a]. But insects can also orient in a fixed direction irrespective of the direction of the wind (in as far as this is feasible when flying at altitudes where the winds are strong) [Schaefer, 1976;Riley and Reynolds, 1986;Chapman et al, 2010].…”