Keep your enemies closer: enhancing biological control through individual movement rules to retain natural enemies inside the field

Abstract

Abstract. Biological control of pests aims at lowering population levels of pest species by favouring natural enemies, in order to reduce the use of pesticides. The movement behaviour of natural enemies is decisive in the success of biological control: when low habitat quality hinders the diffusion of natural enemies from the border, the density of natural enemies may frequently be heterogeneous inside agricultural plots. We hypothesise that the specific relationship between habitat quality and movement behaviour may allow the improvement of biological control by means of a careful allocation of habitat qualities inside and around the plot. We used three tested individual-based movement models, with different levels of complexity ranging from simple cell-to-cell movements to complex strategies including the sinuosity of the path, boundary crossings, perceptual range, and directional persistence. We used the models to explore how the manipulation of habitat quality may allow significant improvements to the residence time of natural enemies inside the field. We suggest that existing field designs are generally inadequate to retain natural enemies. Mechanistic explanations leading to the highest and lowest residence times are used to draw specific management recommendations.

Effects of hedgerows on the preservation of spontaneous biodiversity and the promotion of biotic regulation services in agriculture: towards a more constructive relationships between agriculture and biodiversity

“…This raises the issue of the quality and the quantity of hedgerows necessary to enhance biotic regulation services at the landscape scale and that of their spatial distribution in relation to crops. Several modelling studies point to a positive relationship between the proportion of semi-natural habitats such as hedgerows and their proximity to crops and biocontrol (Delattre et al 2019;Le Gal et al 2020) These studies also highlight significant interactions between biocontrol and the life history traits of biocontrol agents (especially their dispersal abilities).…”

Assessing the effect of complex ground types on ground‐dwelling arthropod movements with video monitoring: Dealing with concealed movements under a layer of plant residues

“…A typical example is the reluctance of biological control agents to move inside the agricultural plot despite the presence of trophic resources, a frequently proposed explanation for failures in conservation biological control (Albrecht et al, 2020; Al Hassan et al, 2013). Individual‐based models and a meta‐analysis suggest that the interaction between movement behavior and ground type spatial distribution could solve this problem (Albrecht et al, 2020; Collard et al, 2018; Delattre et al, 2019). Therefore, new data on the effect of ground type on patch‐scale foraging movement are necessary for improving conservation biological control at this scale.…”