A new report of the Wildlife Trusts on the state of insects has come out, proving again that insects are declining rapidly in every part of the world. The report focused on the situation in the UK, finding out that around 50% of all insects have disappeared since 1970. Additionally, 23 species of bees and wasps went nationally extinct, and butterflies that are habitat specialists declined by a drastic 77%.
Please also read: Worldwide bird declines – on the way to the second silent spring
The cause of the decline is very likely the continuous habitat loss and heavy use of pesticides. About 70% of Britain is agricultural land, where fewer and fewer insects can survive due to pesticide use and general intensification, reducing the available insect habitat. Despite the well-known negative effects of pesticides, their use has doubled in the last 25 years.
The declines in insect numbers also have a strong impact on other wildlife that feed on them. For example, the spotted flycatcher populations have declined by 93% since 1967. Additionally, the red-backed shrike became extinct in the 1990s in the UK as a result of insect declines and agricultural intensification.
Why are insects declining?
Agricultural intensification harms insects on multiple fronts. With monocultures, many insects lose their food source as only a minority of the species will feed on the crops. Additionally, many insect species require a mosaic of habitats to be able to survive, as they need different habitats in their lifecycle. Thus, the large monocultural fields with few hedges are like an ocean of unsuitable habitat for them. While there are islands of suitable habitat still available, they might be too far for insects to reach. Besides, pesticides directly kill pest insects, but also many insects that are not targeted. An additional issue are also invasive species, especially plants, that are outcompeting native species. Many insects cannot feed on these invasives, therefore there is even less food available for them.
As large fields become inhabitable, gardens become more and more important habitats for insects, helping them survive. There are many ways to make a garden insect-friendly, such as not using pesticides or by building insect hotels. Recently, the European Wilderness Society did a project called Insect Respect with youngsters. The aim was to educate the youth about the importance of insects and their declines, and to build insect hotels. The project, organised by one of the Interreg Volunteers was a very successful event with international participants!