Rare beetle discovered in Wildnispark Zurich
Bolitophagus reticulatus is a very rare, demanding beetle species and only lives in areas where nature is allowed to be pristine. Where dead and weakened trees are not removed from the forest and tinder fungi thrive as a result. At the end of June 2024, the beetle was detected in Sihlwald by a researcher from Bern University of Applied Sciences BFH. This is the first record in the canton of Zurich, and it has also rarely been sighted in the rest of Switzerland. The species had presumably been almost extinct in Switzerland for decades.
The Sihlwald Nature Discovery Park is the largest natural forest reserve in the canton of Zurich. Since 2000, the former commercial forest has been allowed to revert to a wilderness. Dead trees are not removed here. This has a positive effect on biodiversity. For example, the tinder fungus can be observed more and more frequently on the trunks of dead beech trees in the Sihlwald. Its fruiting body serves as a food source and habitat for numerous insect species, in particular Bolitophagus reticulatus, the notch-necked tinder fungus beetle. This beetle grows to around 6 to 7 millimetres in size and is a clear indicator of a forest's closeness to nature.
"This is the first record of this beetle species in the canton of Zurich," explains Thibault Lachat, professor at the BFH-HAFL School of Agricultural, Forest and Food Sciences, who regularly conducts research in the Sihlwald forest. He discovered some specimens in the Sihlwald on June 25, 2024 during a control tour. "The species has only rarely been sighted in the rest of Switzerland," explains the forest ecologist. The species was probably almost extinct in Switzerland." It is currently slowly spreading again in Europe. "Bolitophagus reticulatus is considered to be very mobile; the species will presumably re-colonize wherever the tinder fungus can establish itself with numerous fruiting bodies."
The researcher sees this as a positive sign: "To preserve our biodiversity, we need a lot of deadwood, i.e. a good mix of near-natural commercial forests and forest reserves." The discovery of Bolitophagus reticulatus in the Sihlwald Nature Discovery Park shows that the area is developing into an important hotspot and reservoir for biodiversity. "Natural forest reserves such as the Sihlwald have an important function: larger populations of rare species can form here and recolonize other habitats from this reservoir."
