Most insect field guides provide information to help you identify adult insects. Whether you are a dedicated insect enthusiast or a gardener trying to control a plant pest, you may need to identify immature insects from time to time.
About 75% of insects undergo a complete metamorphosis with a larval stage. In this stage, the insect feeds and grows, usually molting several times before reaching the pupal stage. The larva looks quite different from the adult it will eventually become. Identifying insect larvae can be challenging. Your first step should be determining the larval form. Entomologists describe 5 types of larvae, based on their body shape, as follows.
Eruciform larvae look like caterpillars (and in most cases, are caterpillars). The body is cylindrical in shape, with a well-developed head capsule and very short antennae. Eruciform larvae have both thoracic (true) legs and abdominal prolegs.
Eruciform larvae may be found in the following insect groups:
Scarabaeiform larvae are commonly called grubs. These larvae will usually be curved or C-shaped, and sometimes hairy, with a well-developed head capsule. They bear thoracic legs, but lack abdominal prolegs. Grubs tend to be slow or sluggish.
Scarabaeiform larvae are found in some families of Coleoptera (specifically, those classified in the superfamily Scarabaeoidea).
Campodeiform larvae are usually predaceous and typically quite active. Their bodies are elongate but slightly flattened, with well-developed legs, antennae, and cerci. The mouthparts face forward, helpful when they are in pursuit of prey.
Campodeiform larvae may be found in the following insect groups:
- Borror and DeLong's Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson.
- Encyclopedia of Entomology, 2nd edition, edited by John L. Capinera.
- Entomologists' glossary, Amateur Entomologists' Society (AES) website. Accessed March 22, 2013.
- Glossary, BugGuide.Net. Accessed March 22, 2013.