Abstract
AbstractInvertebrate seed predators (ISPs) are an important component of agroecosystems that help regulate weed populations. Previous research has shown that ISPs' seed preference depends on the plant and ISP species. Although numerous studies have quantified weed seed losses from ISPs, limited research has been conducted on the potential for ISPs to consume cover crop seeds. Cover crops are sometimes broadcast seeded, and because seeds are left on the soil surface, they are susceptible to ISPs. We hypothesized that (1) ISPs will consume cover crop seeds to the same extent as weed seeds, (2) seed preference will vary by plant and ISP species, and (3) seed consumption will be influenced by seed morphology and nutritional characteristics. We conducted seed preference trials with four common ISPs [Pennsylvania dingy ground beetle (Harpalus pensylvanicus), common black ground beetle (Pterostichus melanarius), Allard's ground cricket (Allonemobius allardi) and fall field cricket (Gryllus pennsylvanicus)] in laboratory no choice and choice feeding assays. We compared seed predation of ten commonly used cover crop species [barley (Hordeum vulgare), annual ryegrass (Lolium multiflorum), pearl millet (Pennisetum glaucum), forage radish (Raphanus sativus), cereal rye (Secale cereale), white mustard (Sinapis alba), crimson clover (Trifolium incarnatum), red clover (Trifolium pratense), triticale (×Triticosecale) and hairy vetch (Vicia villosa)] and three weed species [velvetleaf (Abutilon theophrasti), common ragweed (Ambrosia artemisiifolia) and giant foxtail (Setaria faberi)]. All four ISPs readily consumed cover crop seeds (P < 0.05), but cover crops with hard seed coats and seed hulls such as hairy vetch and barley were less preferred. Our results suggest that farmers should select cover crop species that are avoided by ISPs if they plan on broadcasting the seed, such as with aerial interseeding.
Highlights
Invertebrate seed predators (ISPs) such as carabid beetles (Coleoptera: Carabidae) and crickets (Orthoptera: Gryllidae) are key drivers of weed seed destruction (Westerman et al, 2003; Kulkarni et al, 2015a) and the subsequent reduction of weed emergence (White et al, 2007; Kulkarni et al, 2015b)
Multiple generalist seed predators contribute to post-dispersal predation, which is a form of biological control that can reduce weed populations (Crawley, 1992)
We hypothesized that (1) ISPs will consume cover crop seeds to the same extent as weed seeds, (2) seed preference will vary by plant and ISP species, and (3) seed consumption will be influenced by seed morphology and nutritional characteristics
Summary
Invertebrate seed predators (ISPs) such as carabid beetles (Coleoptera: Carabidae) and crickets (Orthoptera: Gryllidae) are key drivers of weed seed destruction (Westerman et al, 2003; Kulkarni et al, 2015a) and the subsequent reduction of weed emergence (White et al, 2007; Kulkarni et al, 2015b). In addition to field research, laboratory feeding assays have been used to determine weed seed preference by ISPs, and results determined in the laboratory often translate directly to field preference (Honek et al, 2006; Petit et al, 2014; Ward et al, 2014). Constraints such as ISP body size and mouthpart strength determine which seeds can be consumed (Honek et al, 2007; Lundgren, 2009). The Pennsylvania dingy ground beetle (Harpalus pensylvanicus DeGeer) has been the model ISP species for seed preference work. Lundgren and Rosentrater (2007) found H. pensylvanicus preferred species with small, dense seeds with hard seed coats [e.g., redroot pigweed (Amaranthus retroflexus L.); mass ∼0.33 mg; seed coat strength ∼47.81 MPa] compared with large seeds [e.g., ivyleaf morning glory (Ipomoea hederacea L.); mass ∼24.65 mg; seed coat strength ∼3.95 MPa]. Ward et al (2014) found H. pensylvanicus consumed 71% of presented giant
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
