Insect Pollinator Monitoring in and around a Netted Plot of Apple Trees—Biosafety Implications for Genetically Engineered Fruit Trees

Abstract

The complete netting of orchards is one strategy to protect fruit trees from pest and pathogen damage by reducing insect movement. When the cultivated trees were derived from genetic engineering (GE), reduced pollinator movement may also reduce outcrossing to cultivated or wild non-GE trees. We report on a field study over four years in a plot of apple tress supplied with insect side nets and covered with hail nets that were closed from shortly before flowering to harvest. A reduced number of arthropods in general, and large bees in particular, were recorded inside the netted plot compared with outside. However, wild bees colonized the plot before the net was closed and built up populations inside. An additional experiment demonstrated that small bees were able to cross the hail net. While the nets were effective in excluding large bees as active pollen vectors, the proportion of small bees acting as such remained unquantified. Furthermore, a companion study showed occasional cross-pollination events through the netting. For the field release of GE apple trees, acceptable levels of outcrossing thus need to be defined.

Environmental DNA metabarcoding of pan trap water to monitor arthropod‐plant interactions

“…Arthropod communities are often targeted using a mixture of active (e.g., sweep netting) and passive (e.g., pan traps) sampling techniques to capture the most accurate representation of taxonomic diversity for a habitat or landscape (Prendergast et al., 2020; Spafford & Lortie, 2013). Pan traps, colored plastic bowls filled with soap water, are often used to sample arthropod pollinators (Meissle et al., 2022; Popic et al., 2013; Saunders & Luck, 2013) and are an efficient and cost‐effective means to measure arthropod diversity without observer bias (Westphal et al., 2008; Wilson et al., 2008). Increasingly, pan traps are used to survey in both agricultural and natural landscapes.…”

“…Although like other observation‐based techniques, this method can be time‐intensive (Saunders & Luck, 2013), requires taxonomic expertise (Joshi et al., 2015), and thus may be challenging to implement on a large scale. Despite these challenges, pan traps still remain a common sampling technique, in both natural and agricultural systems, to survey the taxonomic diversity of arthropod communities (Joshi et al., 2015; Meissle et al., 2022; Popic et al., 2013), although the potential plant taxonomic information incidentally captured by using this method remains largely unexplored.…”