Seasonal attraction of the rice bug, Leptocorisa chinensis Dallas (Heteroptera: Alydidae), to synthetic attractant

Abstract

To improve the procedures for estimating the abundance of the rice bug, Leptocorisa chinensis Dallas (Heteroptera: Alydidae), field monitoring using traps baited with synthetic attractant was conducted in Tsukuba, central Japan from 2002 to 2006. A mixture of (E)-2-octenyl acetate and 1-octanol, in a ratio of 5 : 1 and incorporated into a plastic pellet, was used as bait on sticky boards and placed at study sites from early June to the end of October. The attractantbaited traps were able to detect the starting of the migration period of the overwintered generation and the population increase of the first generation. The number of trapped insects decreased rapidly after early September, while the number of insects in second generation increased in the grassy weeds field. The decreased temperatures and shorter daylength of autumn (which will have induced reproductive diapause) may have affected the attractiveness of the baited traps. The ratio of males to all captured L. chinensis was 0.88-0.96. Most captured adults had no food in their stomachs, and most males were sexually mature. These results indicate that the males trapped had actively moved for two possible reasons: to search for food and/or to search for females. Based on comparisons between the results of baited trap monitoring and sweep-net surveys, it was considered that immigrant period and density of L. chinenis in the poaceous plants fields depend on the density of dispersal individuals and the heading period of the plants.

A pecky rice-causing stink bug Leptocorisa chinensis escapes from volatiles emitted by excited conspecifics

“…Leptocorisa chinensis males are strongly attracted to a 5:1 mixture of (E)-2-octenyl acetate and octanol (Leal et al 1996;Watanabe et al 2009;Fukatsu et al 2012). These compounds were also detected from males and females at ratios of approximately 2:1 and 20:1, respectively, in our study.…”

Diurnal locomotion activity of adult rice bug, Leptocorisa chinensis (Hemiptera: Alydidae), at different ages, measured by actograph and video camera

“…L. chinensis enters reproductive diapause under a short daylength in autumn in the adult stage (Takeuchi et al 2005;Tachibana and Watanabe 2007), and is thought to migrate to coniferous trees for overwintering (Watanabe et al 2009). Thus, it is possible that diapause induction might enhance the locomotion activity of the bug, especially daytime activity (because the low temperature of autumn nights will depress locomotion activity) enabling the insects to migrate to their overwintering site.…”

“…It attracts adult males but not females or nymphs (Leal et al 1996). Recently, a method of monitoring L. chinensis using synthetic attractant has been developed by Watanabe et al (2009) in order to survey the occurrence of the bug. They pointed out that trap capture does not always correspond to the population densities of the bugs inhabiting an area, but actually indicates the number of migrating L. chinensis males.…”

“…L. chinensis adults (sexes were mixed) released in a cage moved actively at night (Kainoh et al 1980). Most of the males captured by traps with synthetic pheromone were reproductively mature and had no stomach contents (Watanabe et al 2009). Thus, it seems that males with specific physiological traits migrate at night, but this does not mean that all mature and hungry males move actively.…”

Integrated pest management for sustainable rice cultivation: a holistic approach

“…Synthetic pheromones are currently available for striped stem borer, Chilo suppressalis, ricebug, Leptocorisa chinensis Dallas and Indian meal moth, Plodia interpunctella (Hubner). These pheromones are rarely employed as sex disruptors but used more commonly in pest monitoring to help predict pest densities or to identify peaks in seasonal occurrence as a guide for management interventions (Kojima et al 1996;Watanabe et al, 2009;Witzgall et al, 2010;Wilson et al, 2015).…”