How Insects Adapt To Human Environmental Changes

Insects, though tiny and numerous, are invaluable organisms to the world’s ecology, and any disruption of their behavior (or numbers) will likely have major effects. The changes that humans make to the environment to improve our own livability are often too rapid for other animals to adapt to physically. Instead, most adaptations to our activity come in the form of altered behavior, which is much more malleable than genetics. This paper examines some of the changes in behavior that insects have taken in response to human-induced rapid environmental change (HIREC) and their possible effects.

Animals who are less specialized in their diets may be better at withstanding HIREC. The success of some invasive ant species has been attributed partially to the breadth of their diets. Species who formerly had only a few food sources have broadened their appetites in response to changes in their habitat. However, some animals may be forced into specialization, if the majority of their former food choices are eliminated or decreased. 

Many insects rely on sound for their mating rituals, notably crickets and grasshoppers. Humans, however, are noisy. Industry, transportation, and energy are quite loud, and many of these animals have changed their songs’ frequencies to be better heard. Light pollution can also pose a problem for insects who rely on bioluminescence for their mating displays, like glowworms and fireflies. Areas with high levels of artificial light may be avoided by these animals.

Even simple things like activity levels and feeding locations can be affected by HIREC. Aphids, for example, are more likely to eat from the undersides of leaves on hot days, which are becoming more common as the climate warms from human emissions. Some tropical butterflies are less active above a certain temperature threshold, which can affect their survivability and range. Not all HIREC-induced behavior is negative, however. Sweet bees, for example, become more social at higher temperatures, which increases their pollination activity. 

Furthermore, the loss of non-insect species can lead to changes in the behavior and habitat of insects. One example comes from Africa, where acacia trees once supported colonies of a species of ant who would defend them against large herbivores. However, human activity drastically reduced the population of large herbivores in Africa, which resulted in the acacia trees devoting fewer resources to maintaining these ant colonies. Other ants and insect parasites were then able to invade the acacia trees. 

The authors note that very little research has been done in this field, despite the possible ramifications to endangered species. The few behavioral changes that have been noted are either insufficient to ensure long-term survivability, or maladaptive – actually increasing the negative effects of HIREC, rather than mitigating them. If we are to avoid causing even more harm to insects than we already have, studying the effects of HIREC on their behavior is crucial. Then, with that knowledge, we can change our own habitats to be more friendly to their needs – reducing noise and light pollution, for example, or planting a wider variety of plants in urban areas.