Predatory arthropod community composition in apple orchards: Orchard management, landscape structure and sampling method

Abstract

Studies on predatory arthropods in agricultural areas seldom include Diptera other than hoverflies, partly because common sampling methods are less effective for capturing species that easily fly off when disturbed. To study the effect from this bias when describing the predator community, we compared traditional beat sampling of K E Y W O R D S Diptera, Dolichopodidae, Hybotidae, integrated pest management, organic production This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Assessing flower-visiting arthropod diversity in apple orchards through environmental DNA flower metabarcoding and visual census

“…arthropod behaviours(Deiner et al, 2017;Todd et al, 2020). Hence, the utilisation of either technique on its own has its limitations for arthropod diversity assessment and forthcoming studies could consider employing both in unison to get a better overview.Implications on orchard managementsKnowledge on beneficial and detrimental arthropods visitors to apple orchards is crucial to improving management techniques(Hambäck et al, 2021). Our study detected the presence of two important apple pests, Operophtera and Yponomeuta moths, that feed on developing apple fruitlets and leaves which can result in high economical losses if not controlled(Svensson et al, 1999; CFIA, 2006;Turner et al, 2010).…”

“…Increasing the number of biological and technical replicates, albeit at an increased cost and time, can also help to better detect rare and cryptic species(Deiner et al, 2017;Ruppert et al, 2019). DNA traces in flowers may be shortlived and inclusion of additional sampling in the afternoons may better capture traces of dayactive flower visitors.Knowledge on beneficial and detrimental arthropods visitors to apple orchards is crucial to improving management techniques(Hambäck et al, 2021). Our study detected the presence of two important apple pests, Operophtera and Yponomeuta moths, that feed on developing apple fruitlets and leaves which can result in high economical losses if not controlled(Svensson et al, 1999; CFIA, 2006;Turner et al, 2010).…”

“…Many of these species are currently facing multiple threats linked to anthropogenic activities such as land management, pesticides, and invasive species (García and Miñarro, 2014 Species diversity, or more specifically complementarity, has been demonstrated to increase crop productivity and sustainability (Klein, 2011;Russo et al, 2015;Rader et al, 2016;McCravy, 2018;Nunes-Silva et al, 2020). The diversity and abundance of pollinators and natural enemies of insect pests are limited by the amount of non-crop flowering habitat (hedgerows or flower strips) and pest management practices (Rader et al, 2020;Hambäck et al, 2021). Therefore, the conservation of semi-natural habitats in managed landscapes, such as apple orchards, is crucial to improving arthropod services (Klein et al, 2007;Joshi et al, 2016;Herz et al, 2019;Pardo and Borges, 2020).…”

“…Future studiesAgricultural systems are facing several threats such as pollinator decline and climate change(García and Miñarro, 2014;McKerchar et al, 2020;Pardo and Borges, 2020). Having a high diversity of arthropods in these systems is seen as a way to overcome some of these threats(Russo et al, 2015;Dunn et al, 2020;Hambäck et al, 2021). Hence, the study of flower visitors is an important step towards preserving agricultural systems(Klein et al, 2007;Leonhardt et al, 2013;Porcel et al, 2018).We demonstrated in our study using both visual census and metabarcoding the existence and importance of wild non-bee pollinators such as Diptera, whose presence in apple orchards has been underestimated or even understudied in previous studies(Delaplane et al, 2000; Ramírez and Davenport, 2013; Rader et al, 2020).…”

Insect and insecticides in agricultural landscapes; socio-ecological challenges and patterns

“…Hence, the differences in the catches between the two sampling methods in our study may reflect differences in behaviour and activity of species groups (Doxon, Davis and Fuhlendorf, 2011). As such, sweep netting and sticky traps sample a different arthropod community (Schmidt, O'Neal and Dixon, 2008;Hambäck et al, 2020), and this may blur relationships between arthropod abundance, insecticide intensity and landscape context.…”