Promoting sustainable biological control by bats in apple orchards – from the plot to the landscape

Dates : from 01/11/2024 to 31/10/2027

Insectivorous bats (chiroptera) are important predators of a wide variety of arthropods which are crop pests (cause damage). They can consume from 40 up to more than 100% of their body weight in arthropods per night. Bats can therefore significantly reduce crop damage and increase yields. However, a sharp decline in their populations has been documented in the Hexagon (43%), highlighting conservation issues as well as loss of pest control.

 

Apple growing is the most profitable tree-growing sector, with table apples being the most widely produced and consumed fruits in France. To produce such large amounts of fruits and meet the sector's quality standards, apple orchards are managed very intensively and rely on a heavy use of pesticides, which have negative effects on humans, non-human living organisms, including bats, and the environment (One Health). Alternative methods to the use of insecticides have therefore been increasingly developed in recent years in apple orchards, in particular the settlement and deployment of anti-pest nets (anti-codling moth).

 

Highly sensitive to their environment (bioindicators), bats respond to local vegetation structure, landscape context, ecological connectivity and local agricultural practices. In this project, we study specifically the interactions between bats (with acoustic recorders and analysis of their calls), arthropods (pests and non-pests, using traps), agricultural practices, landscape, and ecological connectivity in apple orchards in three main lines:

1) Study of the response of insectivorous bats to the presence and deployment of single-row anti-pest nets in apple orchards.

2) Study of the spatio-temporal relationships between bat activity and the population dynamics of a few major problematic pests (codling moth and fruit moths) in apple orchards according to the level of functional ecological connectivity of the landscape surrounding the plots.

3) Study of the relationships between bat activity/diversity, abundance/diversity of functional entomological groups (phytophagous, recyclers, generalists, mycetophagous, zoophagous) and level of functional ecological connectivity at three scales (plot, landscape and wider scale).

 

This thesis is part of the national Chiroverger project led and funded by the French Office for Biodiversity, targeting bat conservation and bat natural ennemy role preservation in orchard landscapes.

PhD thesis co-funded by the OFB and INRAE Plant Health and Environment department (SPE).