Life tables and demographic statistics of Russian wheat aphid (Hemiptera: Aphididae) reared at different temperatures and on different host plant growth stages

Zhanshan (Sam),Edward J Bechinski

doi:10.14411/eje.2009.026

Abstract

Laboratory experiments were used to investigate the influences of 25 combinations of temperature and barley plant growth stage (5 Ă 5 factorial combination of temperature and barley plant growth stage) on the development, survival and reproduction of the Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko). For each of the 25 treatments, the developmental time and nymphal production of 72 RWA individuals were recorded (1800 RWA in total) throughout their entire lifetimes. The collected data were used for analyzing demography, modelling phenology, and simulating population growth of RWA. In this paper, the results of demographic analyses are reported. Specifically, for each treatment, cohort life tables, reproductive heterogeneity tables (parity and birth intervals), and reproductive schedule tables were constructed, and demographic parameters such as intrinsic rate of increase, life-span, fecundity, life table entropy, etc. calculated. Based on these analyses, the most important summary demographic statistics are reported. Using the intrinsic rate of increase (rm) as an example, a procedure is demonstrated that builds a dynamic rm model by applying the Best Subset Regression approach. A more comprehensive (considering reproductive heterogeneity and schedule tables) yet concise (comprising dynamic rm models) demographic model than that based on standard life table analysis alone is presented.

Highlights

Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae), was first detected in Texas in 1986, and by the early 1990’s it had become established in the US west of the 100th meridian and in three adjoining western Canadian provinces (Webster et al, 1996)
We report the population demographic statistics needed for producing traditional cohort life tables and analyze the effect of temperature and barley plant-growth stage on RWA population growth
Given the extensive data collected from the experiments (1800 RWA in 25 treatments), this paper exclusively focuses on the survival and reproduction statistics of RWA demography, and the development and phenology aspects of RWA is reported elsewhere (Ma & Bechinski, 2008)

Summary

Introduction

Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae), was first detected in Texas in 1986, and by the early 1990’s it had become established in the US west of the 100th meridian and in three adjoining western Canadian provinces (Webster et al, 1996). In its first decade in North America, the RWA caused significant damage and posed a serious threat to wheat and barley production in the United States and Canada. The damage caused by RWA seems to be under control, it is still important to understand this aphid’s population demography. Qureshi & Michaud (2005) compare the biology of RWA with that of the two other cereal aphids, the greenbug [Schizaphis graminum (Rondani)] and bird cherry-oat aphid [Rhopalosiphum padi (Linnaeus)]. They discuss the importance of the differences and especially the interference among the three aphid species in the development and evaluation of new resistant wheat cultivars. Demography and phenology are frequently the focus of studies on aphid ecology and biology (Hentz & Nuessly, 2004; Liu, 2004, McCornack et al, 2004; Qureshi & Michaud, 2005)

Methods

Results

Conclusion