Insects are indispensable actors within global agri-food systems and ensure the delivery of myriad ecosystem services. A progressive decline in insect numbers — as inflicted by habitat loss, pollution or intensive agriculture — can jeopardize a sustained provisioning of those services. Though we routinely disregard how insects help meet multiple sustainable development challenges, a gradual insect decline can have grave, long-lasting consequences.
Insect populations are declining even in protected areas, but the underlying causes are unclear. Here, I consider whether the factors driving the loss of insect diversity include invasive and/or introduced insects transmitting pathogens to less-resistant native species. The introduction of insects into new areas for biocontrol, to promote pollination, or for mass rearing in insect farms, threatens the health and diversity of indigenous insects by the co-introduction of entomopathogens whose spillover is difficult to control.
