Abstract
Non-native plant species can provide native generalist insects, including pests, with novel food and habitats. It is hypothesized that local and landscape-level abundances of non-native plants can affect the population size of generalist insects, although generalists are assumed to be less sensitive to habitat connectivity than specialists. In a heterogeneous landscape in Japan, the relationship between the density of a native pest of rice (Stenotus rubrovittatus (Matsumura) (Heteroptera: Miridae)) and the abundance of Italian ryegrass (Lolium multiflorum Lam. (Poales: Poaceae)), a non-native meadow grass known to facilitate S. rubrovittatus, was analyzed. Statistical analyses of data on bug density, vegetation, and the spatial distribution of fallow fields and meadows dominated by Italian ryegrass, obtained by field surveys, demonstrated that local and landscape-level abundances of Italian ryegrass (the unmowed meadow areas within a few hundred meters of a sampling plot) positively affected bug density before its immigration into rice fields. Our findings suggest that a generalist herbivorous insect that prefers non-native plants responds to spatial availability and connectivity of plant species patches at the metapopulation level. Fragmentation by selective mowing that decreases the total area of source populations and increases the isolation among them would be an effective and environmentally-friendly pest management method.
Highlights
Some native insect herbivores respond quite sensitively to invasions of non-native plant species in a wide range of ecosystems (Ellingson and Andersen 2002, Cronin and Haynes 2004, de Groot et al 2007, Yoshioka et al 2010a)
Non-native plant invaders, can facilitate some generalist insect herbivores by providing trophic subsidies and/or novel habitats (Rodriguez 2006), and thereby exert indirect negative effects on native plants and/or crops (Malmstrom et al 2005, Carrière et al 2006)
Landscape effects of a non-native grass on the density of a native mirid bug This study demonstrated that local and landscape factors had significant positive effects on S. rubrovittatus density in unmowed meadows and fallow sites scattered in an agricultural landscape
Summary
Some native insect herbivores respond quite sensitively to invasions of non-native plant species in a wide range of ecosystems (Ellingson and Andersen 2002, Cronin and Haynes 2004, de Groot et al 2007, Yoshioka et al 2010a). Such bottom-up effects on herbivore populations by non-native plants can cascade to upper trophic levels (Burghardt et al 2009, Heleno et al 2009) and seriously affect the entire food web in an ecosystem (Tallamy 2004). The spatial distribution of the patches can produce an “emergent” landscape-level effect of a plant invader on herbivore population dynamics, which differs from the effects of the summed area of the individual patches
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
