Do rice water weevils and rice stem borers compete when sharing a host plant?

Abstract

Abstract:The rice water weevil (RWW) Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae) is an invasive insect pest of rice Oryza sativa L. in China. Little is known about the interactions of this weevil with indigenous herbivores. In the present study, adult feeding and population density of the weevil, injury level of striped stem borer Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) and pink stem borer Sesamia inferens (Walker) (Lepidoptera: Noctuidae) to rice, as well as growth status of their host plants were surveyed in a rice field located in Southeastern Zhejiang, China, in 2004 with the objective to discover interspecific interactions on the rice. At tillering stage, both adult feeding of the weevil and injury of the stem borers tended to occur on larger tillers (bearing 5 leaves) compared with small tillers (bearing 2~4 leaves), but the insects showed no evident competition with each other. At booting stage, the stem borers caused more withering/dead hearts and the weevil reached a higher density on the plants which had more productive tillers and larger root system; the number of weevils per tiller correlated negatively with the percentage of withering/dead hearts of plants in a hill. These observations indicate that interspecific interactions exist between the rice water weevil and the rice stem borers with negative relations occurring at booting or earlier developmental stages of rice.

Wild barley introgression lines revealed novel QTL alleles for root and related shoot traits in the cultivated barley (Hordeum vulgareL.)

“…Both of these roots eventually initiate lateral roots (secondary and tertiary roots) on which water and nutrient absorbing root hairs are developed [ 13 ]. It has been reported that the number of roots in a plant is closely related to the tiller number per plant [ 14 , 15 ]. For example, Anderson-Taylor and Marshall [ 16 ] reported seminal and nodal roots of spring barley ( H. distichum L.) comprised of 40 and 60 percent, respectively of total roots and nodal root dry weight was correlated with primary tillers.…”

Influence of Temperature on the Interaction for Resource Utilization between Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), and a Community of Lepidopteran Maize Stemborers Larvae

“…The lower interspecific competition between FAW and stemborers than within stemborers could be explained by the fact that in contrast to stemborers, which only feed on leaves up to the third larval instar stage (even earlier stage for S. calamistis), FAW is a pure foliar feeder; thus, as on live plants, FAW larvae remained on the surface whereas borer larvae penetrated into the diet, where after the direct competition ended between FAW and stemborer larvae. Similarly, Shi et al [43] reported no evidence of interspecific competition between the rice water weevil, a leaf feeder and rice stemborers at the tillering stage in contrast to the booting or earlier developmental stages of rice.…”