August 15, 2022

An insectivore is an animal that feeds on insects or other arthropods (arachnids, myriapods, etc.). Insectivorous animals belong to different systematic groups, so this feeding behavior should not be confused with the ancient taxon called Insectivora (Insectivora) which includes insect-eating mammals. Finally, the consumption of insects by humans is called entomophagy.

An important food source

Insects are animals with a wide terrestrial range. They are present almost everywhere on the globe (with the main exception of the poles). They also occupy numerous ecological niches: they can be terrestrial (even underground) or flying, aquatic, living on the ground or in vegetation… and are often endowed with a high reproductive power. It is therefore logical that they represent an important source of food for many predators. In addition, their small size and the weak defense capacity of many of them make them preferred prey for small to moderately sized animals.

Insectivorous animals

Many animals are insectivores, regular or occasional. In almost all terrestrial environments, they form guilds that exploit the different compartments of ecosystems, from the subsoil to the atmosphere, passing through the mucinal and herbaceous strata and the different levels of the forest (Forest strata) up to the canopy. Wetlands, from which many insects emerge, are also home to many insectivores, some of which are aquatic and others aerial. Insectivores include many predatory insects and arachnids, reptiles, amphibians, fish, some birds, but also mammals; from the tiny dwarf shrew (1.3 to 3.5 g) to the large anteater weighing up to over 41 kg and ingesting up to 30,000 termites per day, including Chiroptera, the Pyrenean desman (aquatic) or wild boar (omnivorous, large consumer of insect larvae). In the old classifications, the Insectivora form a group of mammals which includes, for example, hedgehogs and shrews. The group was indeed named after this diet but the species it contains may have a more varied diet. Thus, the common hedgehog feeds on insects but also on worms, molluscs, reptiles, amphibians, rodents, amniotic eggs and chicks or even fruits and berries, which makes this animal an omnivorous Insectivora. Let us also mention the case of parasites or insects which live totally or almost at the expense of other insects, then called entomophagous parasites or entomophagous insects.

Pest Control

The elimination of insects by insectivores is a way of biological control.

Decline of insectivores

In all industrial countries, there is a massive and general, but not uniform, decline in many insectivorous species (birds, bats and amphibians in particular), including in Europe and North America. In North America, this decline is highest in agricultural and artificial areas. Data from the North American Bird Breeding Survey (BBS) from 1966 to 2006 show that passerines in the insectivore guild declined faster and more massively than other passerines sharing their habitat. And this decline follows a clear geographic gradient (aerial insectivores are becoming rarer the farthest in northeastern North America in areas of intensive agriculture). The decline is stronger and faster in highly migratory species (which must eat more and consume more fat reserves), compared to species migrating over short distances. In temperate zones, many insectivores must hibernate or migrate to