Communities of Canopy-Dwelling Arthropods in Response to Diverse Forages

Core Ideas: True bugs, grasshoppers, and spiders were among the more abundant canopy arthropods in pastures. Old world bluestem had among the least abundance of canopy arthropods in 2 out of 3 yr. Old world bluestem provides a less favorable habitat than alfalfa for canopy insects. ‘WW-B.Dahl’ old world bluestem (OWB) [Bothriochloa bladhii (Retz) S.T. Blake] is an important warm-season perennial grass pasture in semiarid western Texas. This grass deters pestiferous ants; however, its effect on canopy-dwelling insects is not documented. The abundance of canopy-dwelling arthropods among OWB, OWB–alfalfa (Medicago sativa L.), alfalfa, and native grass pastures was compared by sweep-net sampling over 3 yr (2014–2016). Forty-six families of nine insect orders and a single family of spider (Araneae: Araneidae) were identified. Among total individuals, 85% were insects and 15% were spiders. Housefly (Musca spp., Diptera: Muscidae), potato leafhopper (Empoasca spp., Hemiptera: Cicadellidae), lygus bug (Lygus hesperus, Hemiptera: Miridae), and spur-throated grasshopper (Melanoplus spp., Orthoptera: Acrididae) were other abundant taxa. Among the insects collected, spur-throated grasshoppers were the most abundant, comprising 12% of total taxa. Alfalfa hosted the greatest number of total insects, including pests such as potato leafhopper and lygus bug. Lower abundances of pestiferous insects were found in OWB while still hosting greater abundances of some arthropods of ecological significance such as spider and ladybird beetle (Hippodamia spp., Coleoptera: Coccinellidae).