Modelling the effects of field spatial scale and natural enemy colonization behaviour on pest suppression in diversified agroecosystems

Abstract

1. Diversifying agroecosystems by establishing or retaining natural vegetation in and around crop areas has long been recognized as a potentially effective means of bolstering pest control by attracting more numerous and diverse natural enemies, though outcomes are inconsistent. 2. Little is known about the underlying mechanisms driving such differences in species responses, creating challenges for determining how best to manage landscapes for maximizing environmental services such as biological control. 3. We address here gaps in our understanding of the link between non-crop vegetation in field margins and pest suppression by using a system of partial differential equations to model population-level predator-prey interactions as well as spatial processes in order to capture the dynamics of crop plants, herbivores, and two generalist predators. 4. We focus on differences in how two predators (a carabid and a ladybird beetle) colonize crop fields where they forage for prey, examining differences in how they move into the fields from adjacent vegetation as a potential driver of differences in overall pest suppression.

Equivalence between short- and long-distance dispersal in individual animal movement

“…Our work here demonstrates that a property of these heavy-tailed distributions, namely their potential for long-distance dispersal, can be replicated by a simple adjustment to the parameter of the thin-tailed exponential distribution. This is of significance in various movement ecological settings, as the diffusion capability of individual movement has been identified as being an important and appropriate measure in determining dispersal capability (Bearup et al, 2016), with applications in population dispersal (Gurarie et al, 2009;Hapca et al, 2009), individual interactions and contact rates (Bailey, 2023), the spread of diseases (Fofana and Hurford, 2017;Ahmed et al, 2021a), pest monitoring (Petrovskii et al, 2014;Banks et al, 2020), and foraging behaviour (Humphries et al, 2010;James et al, 2011). Below we detail two ecological settings in which the work presented here has an immediate application.…”

Walking behaviour in the ground beetle,Poecilus cupreus: dispersal potential, intermittency and individual variation

“…Banks et al . (2020) looked at the expected affect ladybirds and P . cupreus had on controlling aphid invasions of agricultural fields, with the aim of providing a pest management structure to efficiently eradicate aphid populations.…”

“…As such, ‘beetle banks’ have been specifically created in farmland across the UK and Europe as overwintering habitats for beneficial invertebrates (Thomas et al ., 1991; MacLeod et al ., 2004). Knowledge of dispersal into fields from such areas and the effects of biological characteristics of individual species and how this leads to their observed distribution in agricultural landscapes is key to understanding the maintenance of metapopulations and the dynamics of predator–prey interactions (Petrovskii et al ., 2014; Bastola and Davis, 2018; Banks et al ., 2020). This is particularly relevant in the context of climate change and habitat fragmentation, for which it is important to be able to predict the effects of changes to the environment on species of economic and ecological importance.…”

Foliage and ground spiders respond differently to a semi‐natural habitat‐vineyard gradient

“…2012). These various scenarios highlight the difficulty in defining an optimal management landscape to maximize ecosystem services, such as biological control (Banks et al., 2020), and emphasize the importance of conducting more studies in different crops and regions.…”

“…Taxa with good dispersal skills (flying insects and ballooning in spiders) may be influenced by non-crop habitats at the landscape scale whereas the presence of local contiguous non-crop habitats may be important for taxa with poorer dispersal abilities, mostly by walking (Thomson & Hoffmann, 2010;Sivakoff et al 2012). These various scenarios highlight the difficulty in defining an optimal management landscape to maximize ecosystem services, such as biological control (Banks et al, 2020), and emphasize the importance of conducting more studies in different crops and regions.…”