I know my title is a lazy reference to a scene from the Monty Python movie The Life of Brian, but I think it is appropriate given all the recent talk about the decline of insects around the world. Does it matter if all the insects disappear?
Many (most?) people only notice insects when those insects are affecting them directly and in a negative way, e.g. stinging them, biting them, annoying them with buzzing, or chewing on one of their beloved plants (like the Grapevine moth Phalaenoides glycinae larva below).
The vast majority of insects are not pests, nor are they what we might call beneficial insects (i.e. beneficial to us humans). Most insects are just out there doing their thing, being a part of their particular ecosystem, being part of the web of life. Insects play extremely significant roles in pretty much every terrestrial ecosystem on Earth. In fact insects are the biological foundation for terrestrial ecosystems.
Imagine a world without insects and you are imagining a world without many of our pollinators, and therefore many flowering plants. You are also imagining a world without many (most?) insectivorous fish, birds, bats and other small mammals. Then imagine the knock-on effect of losing those animals – for example, what fed on those particular fish or birds? On and on it goes.
A world without insects also means a world without most of the creatures which help break down and bury wood, carcasses and dung (dung beetles like the one pictured above are dung-burying specialists). If we lose the insects we also lose some important soil aerators and fertilizers – for example, in the arid parts of Australia termites and ants replace earthworms.
Maybe we shouldn’t be asking – what have insects ever done for us? Maybe we should just accept that insects are vitally important to the terrestrial ecosystems of this Earth. Maybe we should be asking – what have we ever done for insects?