The use of trap‐nests to support crop pollinators in agricultural areas

Supporting and promoting invertebrate diversity within agricultural ecosystems has numerous benefits, including the provision of pollination services. Many insects, including wild pollinators, require floral resources for food and structural habitat for nesting. To support pollinators, research studies and agri-environment schemes have sought to supplement floral resources, but little is known about the value of different types of nesting habitat enhancements (e.g., trap-nests or bee hotels). We deployed eight replicates of each of three types (bamboo reed, hardwood block and sand/cement brick) of trap-nests at five orchards in two apple and cherry growing regions (Bilpin and Orange) in Australia. Both reed and hardwood block trap-nests attracted a diverse array of invertebrates, such as ants, wasps, spiders and bees, including a cleptoparasitic bee species (Thyreus sp.) not previously recorded in the region. Interestingly, two taxa of native bees (Megachile [Megachile] and Megachile [Eutricharaea]) used the artificial nests and were also observed visiting apple crops. There were significantly more native bees using trap-nests in Orange (n = 65), where orchards are surrounded by agricultural landscapes, than in Bilpin (n = 2), where orchards are surrounded by native forests. Our findings show that artificial nest enhancements are used by native bees, as well as other nontarget invertebrate taxa, some of which can be predators of bees (ants, wasps, and spiders). Nesting habitat augmentation thus has potential to be used as a conservation tool, especially in areas where nesting sites are limited. However, future studies should also consider measures to reduce colonization by non-target taxa