The decline of insects

In recent decades, a certain awareness has been created about an everyday phenomenon that could have serious environmental consequences: insects that hit the windshield of our cars. Or, to be more exact, the fact that the number of insects hitting the windshield has drastically decreased .

It is common knowledge that years ago the windshields were filled with dead insects on long trips, whereas today this does not happen. What could be an anecdotal event of little relevance can also be a symptom of a bigger problem, the decline of insect populations around the world. Does this phenomenon really exist, or is it an unfounded fear unfounded by anecdotal evidence? In this article we will explain it.

Evidence of the decline of insects

The decline of insects
The decline of insects

Insects are the group of living beings with the largest number of species. Specifically, almost as many species of insects are known as the rest of living beings. This implies that it is a group with a great capacity for adaptation, which therefore has a remarkable capacity to respond and adapt to environmental changes.

Variations (decline or increase) in the number of insect species are not a recent phenomenon, since they have been recorded in the fossil record for millions of years. For example, in the Permian-Triassic extinction event (250 million years ago) or in the Cretaceous-Paleogene extinction event (in which the dinosaurs became extinct, 66 million years ago) there was a notable decrease in the number of species of insects. The wide variety of insect species facilitates recovery after these events, although the process can take millions of years to complete.

Some scientists affirm that the sixth great extinction of species is underway , that of the Holocene or Anthropocene (named for the significant impact that humans have on the natural environment). In recent decades, various scientific studies have been published that warn of an alarming decline in the number of invertebrate species.

The most affected species would be those that have less mobility and a smaller area of ​​distribution. Particularly in the last decade, it has been warned of the negative effect that this could have on ecosystems, by decreasing the populations of pollinating insects such as bees , which would directly affect some plants, which are the basis of terrestrial ecosystems.

The aforementioned phenomenon of insect impact on vehicle windshields has been empirically studied to draw conclusions, and these have supported the decline in insect populations . In the early 2000s, when this phenomenon became popular, a study in the UK was carried out in which thousands of drivers placed an adhesive PVC sheet on their front license plate, and recorded the number of insects that they stuck to it. On average, an insect hit the license plate every 8 km. In 2019 the study was repeated with the same methodology and it was discovered that the number of flying insects hits had been reduced by 50% .

Possible causes of insect decline

The decline of insects
The decline of insects

The main cause of the disappearance of biodiversity on a global level is the destruction of natural habitats. This would also explain the decline in insect populations. In addition, there are other particular factors that affect this group, such as the increase in the use of pesticides, the introduction of exotic plant species, climate change or the artificial lighting of inhabited areas, which would especially affect species with nocturnal habits. , like moths. On the other hand, some species of insects could benefit in inhabited environments, such as flies or cockroaches, but this would not be the case for most species.

Conservation measures

Several lines of action have been proposed in order to reduce the impacts on insect populations, and to recover them to levels prior to their decline. One of these measures is the promotion of orchards in urban areas, which allow the feeding and reproduction of pollinating insects. Reducing the use of pesticides and night-time light pollution in urban areas are other measures that would be beneficial for many species of insects.

The example of the bumblebee

An insect that has been particularly affected by different disturbances caused by man is the bumblebee ( Bombus  sp.). This decline is especially worrisome in Europe and North America, due to the loss of habitats and the use of pesticides on agricultural land. Several species of the genus are in danger of extinction, and the species  B. franklini  may have already become extinct.

Bumblebee conservation efforts include a reduction in the use of pesticides and the establishment of sanctuaries so that populations can recover, as well as the introduction of native species to regions where they had disappeared. Another initiative for the conservation of bumblebees is the use of artificial bumblebee nests in orchards and gardens, which these insects can use to breed, which results in greater pollination of plants and a benefit for agriculture.

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