A research team in the Hauts-de-France region of France is studying whether bats can help reduce the need for chemical pesticides in agriculture. The project, known as TransAgroBat, is led by ecology teacher-researcher Diane Zarzoso-Lacoste. It focuses on four bat species and their consumption of harmful insects in agricultural areas of Hauts-de-France, as well as in the Walloon and Flemish regions of Belgium. The team collects and analyzes guano, or bat droppings, from 30 sites in the region, including the agricultural high school Le Paraclet in Amiens, which is surrounded by 120 hectares of farmland. The goal of the study is to use genetic analysis to identify the types of harmful insects consumed by bats, how often they are eaten, and the extent to which the bats are exposed to human-made pollutants. This data will help determine which landscapes are most beneficial for bats and which are more at risk. The team has already conducted two collection periods, one from mid-July to late August, and plans to analyze the samples at the Écologie et dynamique des systèmes anthropisés (Edysan) laboratory, part of the CNRS and the University of Picardie Jules Verne. Preliminary findings suggest that the bats studied consume a significant number of agricultural and forest pests. For instance, the small rhinolophus bat consumed 23 out of 29 identified insect pest species in the analyzed guano samples. The study also found that agricultural pests were frequently present in the bats’ diet—74% of pipistrelle droppings and 65% of mustached bat droppings contained agricultural pests. The long-term aim of the TransAgroBat project is to reduce pesticide use in farmland by highlighting the natural pest control services provided by bats. This could also help slow the decline of several bat species. For example, the mustached bat has lost more than 20% of its population between 2014 and 2023, while the common pipistrelle has lost nearly a quarter of its population in the same time frame. Factors contributing to the decline include habitat loss due to human activities, such as the removal of hedges that serve as bat corridors and hunting grounds, and the use of insecticides that reduce food availability. Urban expansion and energy-efficient building renovations often overlook the needs of bats, leading to the loss of their shelters. Light pollution, transportation infrastructure, and wind farms also increase the risk of mid-air collisions for bats. There are 36 bat species in mainland France, with 22 found in the Hauts-de-France region. These species are protected by law, and promoting healthy bat colonies in agricultural areas could help reduce damage caused by pests like Drosophila suzukii, an invasive Asian fly that threatens small fruits such as cherries and strawberries. This, in turn, may lead to a reduction in the use of insecticides in the region.