Mighty Beetle Halts Highway Construction: How a Tiny Insect Challenged Engineers!

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The scene could be a photograph by Raymond Depardon, known for his aesthetic captures of lesser-known French locales. In the Sarthe countryside, four men sit at a table in front of a small establishment that doubles as a bread depot, kiosk, bar, and canteen in Marigné-Laillé, a village of 1,600 residents. On the menu are shepherd’s pie, salad, and red wine. Among them, three veterans recount their memories of a prolonged fight. This battle in the bocage region pitted the state and highway concessionaire Cofiroute against local residents and activists over the proposed route of the A28 highway, skirting the edge of the Bercé forest. The events unfolded over six years, from 1996 to 2002.

“ The construction of the highway, which was to connect Alençon to Tours via Le Mans, was about to begin. We opposed the project because it was planned to cut through the western part of the Bercé state forest, home to some of France’s finest oak groves. I vividly remember a day in 1996 when we desperately blocked a roundabout ,” laughs Jean-Christophe Gavallet, current president of the France Nature Environment Sarthe association.

Just when it seemed nothing could stop the bulldozers, fate intervened to aid the project’s opponents. “ We were gathered for yet another rally when a little guy parked next to us on his moped. He had the look of a naturalist, with an old sweater and a thick beard. He said, ‘Do you know what I found in the forest ? It lives in cavities and is internationally protected: the stag beetle ‘”, recalls Jean-Christophe Gavallet. “We thought: ‘Jackpot, we have our environmental argument.’ “

The stag beetle ? This beetle, a member of the scarab family, thrives in old trees that have developed cavities filled with a kind of humus over time. Found in forests and bocage landscapes where old pollarded trees provide ideal conditions and cavities form more quickly, it takes 70 to 120 years for oak or ash pollards, compared to 150 to 200 years in managed woodlands!

The challenge faced by this wood-feeding beetle becomes clear. Modern forestry practices seldom leave trees old enough to form natural cavities, drastically reducing the potential habitat for the stag beetle. Additionally, hedgerows in bocage landscapes are often removed due to agricultural restructuring or lack of maintenance.

At that time, defending the stag beetle, already protected under the Bern Convention, became crucial. In an edition of Le Monde dated October 20, 1996, the former president of the Friends of the Bercé Forest Association, Christian Damenstein, stated: “ We are not against the highway, but against its route. Bercé is as worthy as the Marais Poitevin ! Our forest deserves a detour. This beetle story might seem frustrating, but among all the arguments we’ve put forward, it’s the only one with legal basis. It allows us to play in the big leagues and finally be heard. “

Yet, deep down, the fighters knew the project was too far advanced to be abandoned. The legal battle ended in their disfavor in 2002. For the beetle’s defenders, the goal then shifted to securing as much compensation as possible. A series of measures were eventually proposed: a highway interchange was built further away to avoid encroaching on the forest, old trees hosting the beetle were cut at the base and moved to a favorable area, the maintenance of pollard trees housing the creature was extended by ten years, and a site of presence was designated as a Natura 2000 zone…

Back in the small restaurant of Marigné-Laillé, it’s time to leave the table. Anthony Belleteste, the youngest of the group of four, will be our guide this afternoon. He represents the next generation. Employed by the department, he is the coordinator of a Natura 2000 area located west of the Bercé forest, close to the A28 highway.

In this protected natural area, the goal is to preserve ancient grafted chestnut trees, known locally as ‘nouzillards.’ Upon arriving, the view is spectacular. A wide path runs alongside orchards and fields. On the slopes overlooking the sunken path, immense nouzillards with visible scars stretch their branches towards the sky. This is a treasure trove for a variety of species: the little owl, great capricorn beetle, rosalie alpine beetle, several bats including Leisler’s bat, woodpeckers, and more…

“ The aim here is to recreate grafted chestnut trees to provide favorable cavities for the stag beetle and other wood-dependent species. Volunteers among the farmers receive subsidies from the EU. Out of 90 farmers in the area, 10 have agreed to participate ,” whispers Anthony Belleteste.

We head to another natural site managed by the department a few kilometers away, near the highway. Dozens of venerable chestnut trees with gnarled silhouettes rise among younger pines, oaks, or ashes. Strange, large-sized nest boxes are attached to some trunks. Inside, a humus-like mixture favored by the beetles has been recreated using wood chips and organic matter.

This solution, akin to a last chance, addresses the looming gap of aging trees. Installed in 2018, these artificial cavities saw colonization by the stag beetle by 2024. A victory that rewards the tenacity of the former activists: sometimes it pays off when old trees don’t bend in the storm.