Bull beetle is the insect of the year

Bull beetle is the insect of the year

Male bull beetles can be identified by their three horns. © Patrick Urban

This time, the title of “Insect of the Year 2024” goes to the bull beetle (Typhaeus typhoeus), which is native to Germany, as a jury has now announced. The approximately two centimeter long insect belongs to the dung beetle family and owes its name to the two forward-facing horns of its shell. Bull beetles feed on the feces of herbivorous animals such as deer and cattle and play a key role in ecosystems as nature’s “cleaning crew”. But bull beetles are increasingly threatened in this country.

An “Insect of the Year” has been chosen every year since 1999. A board of trustees, which includes well-known entomologists and representatives of scientific societies and institutions, selects an insect from numerous suggestions every year. They often choose species that are of great ecological importance but whose existence is threatened. The election is intended to expand knowledge about the species in question and bring it into greater public awareness.

Feces as a favorite food

The bull beetle (Typhaeus typhoeus) has now been chosen as the title holder for 2024. The 1.4 to two centimeter large beetle is widespread from North Africa through Western Europe to eastern Central Europe and owes its name to the three horns on its forehead, two of which point forward like a bull. The shiny black bull beetles belong to the dung beetle family and, like them, feed on dung. They prefer the feces of herbivorous animals such as rabbits, deer, cattle, sheep and horses and also use it to raise their offspring. To do this, the bull beetles roll the dung into a large ball that can weigh more than 1,000 times their own body weight and then transport it to an underground breeding chamber. When the bull beetle larvae hatch from their eggs in this tunnel system, which is up to 1.50 meters deep, they crawl directly to the feces and feed on it. Within a year, the larvae have developed into adult beetles.

Bull beetle male/female
After mating, pairs of bull beetles build a breeding chamber for their offspring. © Patrick Urban

However, their passion for excrement not only benefits the bull beetles and their offspring, but also the entire ecosystem, as Thomas Schmitt from the German Entomological Institute in Müncheberg explains: “The excrement-eating animals are extremely important for our ecosystems because they ensure that the Leftovers from herbivorous animals can be disposed of quickly and no parasites can settle.” As a rule, bull and other dung beetles make the dung disappear within just a few days. As a side effect, they also transport plant seeds contained in the feces to new places and thus help to spread them. When they eat cow dung, the beetles also ensure that fewer greenhouse gases are released into the atmosphere. In the UK alone, these bull beetle services are worth an estimated €400 million per year.

Endangered by livestock farming

However, bull beetles are finding it increasingly difficult to provide such great services to nature and humans. Since the mid-1980s, their populations have been declining rapidly, as have those of other dung beetle species. The reason: In many areas, cattle are hardly kept on pasture anymore, which means there is a lack of supplies of cow dung. In addition, in modern livestock farming, animals are often no longer only treated with medication for acute illnesses and parasite infestations, but also as a precautionary measure. “Since the active ingredients are excreted by the treated animals, they have an effect beyond the actual target organisms – with consequences for all insects living in or feeding on the feces. As a result, feces-eating beetles die or only reproduce to a limited extent,” explains Werner Schulze from the Nabu Nature Conservation Association.

This fact has now led to dung beetles being one of the most threatened groups among insects. In order to reverse this development, several protective measures for the bull beetle would be necessary in this country. “This includes reducing the use of antiparasitic drugs in pets and farm animals – above all, these drugs may no longer be administered purely prophylactically. Farm animals should also – where possible – become grazers again. Stable housing must be the exception, not the rule,” says Schmitt. After all, the beetles cannot use the dung of the stable animals if it is out of their reach. “Let’s hope that the bull beetle becomes a good ambassador for the important role of feces-eating beetles,” sums up Schmitt.

Source: Senckenberg Society for Natural Research

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