The body forms of the larvae of most endopterygote insects are remarkably similar. I argue that their typical worm-like shape cuts costs; in particular, this allows the larvae to benefit from cheaper moulting and from less costly provision of fuel and oxygen to their respiring tissues. Furthermore, the shape confers a reduction of larval mortality in moulting. Together, these factors allow endopterygote larvae to grow fast and as this speedy growth reduces the dangers of predation, attack by

more »

... asitoids and disease before the larvae can reach adulthood, they increase offspring survival. I argue that this goes a long way to explain the very pronounced success of endopterygote insects.