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Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult). Holometabolism is a synapomorphic trait of all insects in the clade Holometabola. Immature stages of holometabolous insects are very different from the mature stage.
In a complete (holometabolous) metamorphosis the insect passes through four distinct phases, which produce an adult that does not resemble the larva. In an incomplete (hemimetabolous) metamorphosis an insect does not go through a full transformation, but instead transitions from a nymph to an adult by molting its exoskeleton as it grows.
Odonata (dragonflies and damselflies) are insects with an incomplete metamorphosis (hemimetabolous). The aquatic larva or nymph hatches from an egg, and develops through eight to seventeen instars before leaving the water and emerging as the winged adult or imago. [1]
Lepidopterans undergo complete metamorphosis, going through a four-stage life cycle: egg, larva or caterpillar, pupa or chrysalis, and imago (plural: imagines) / adult. The larvae – caterpillars – have a toughened ( sclerotised ) head capsule, chewing mouthparts , and a soft body, that may have hair-like or other projections, three pairs of ...
Other insect orders with more species are all holometabolous, meaning they have a pupal stage and undergo complete metamorphosis. The majority of species are terrestrial, including a number of important agricultural pests, but some are found in freshwater habitats. These include the water boatmen, backswimmers, pond skaters, and giant water bugs.
For most insect species, an instar is the developmental stage of the larval forms of holometabolous (complete metamorphism) or nymphal forms of hemimetabolous (incomplete metamorphism) insects, but an instar can be any developmental stage including pupa or imago (the adult, which does not moult in insects). Two instars of a caterpillar of ...
It displays a complete metamorphosis (egg, larva, pupa, adult), [2] or holometabolous development. [1] The larvae are legless, and have head capsules with mandibulate mouthparts in the Nematocera. The larvae of "higher flies" (Brachycera) are however headless and wormlike, and display only three instars.
An insect's life-cycle can be divided into three types: Ametabolous, no metamorphosis, these insects are primitively wingless where the only difference between adult and nymph is size, e.g. order: Thysanura . [4] Hemimetabolous, or incomplete metamorphosis. The terrestrial young are called nymphs and aquatic young are called naiads.