. Beneficial insects and mites. Mites; Pests; Insects. INSECT METAMORPHOSIS Understanding biological control requires a general knowledge of insect biology. One of the key features of insect growth and development is the process of metamorphosis. The insect cuticle (skin) is a rigid or semi- rigid body covering that provides protection and support but limits growth. In order to increase in size or change form, an insect must shed its old skin and replace it with a new one through a process known as molting. Immature insects undergo two to several molts (the number dif- fers among species) that
. Beneficial insects and mites. Mites; Pests; Insects. INSECT METAMORPHOSIS Understanding biological control requires a general knowledge of insect biology. One of the key features of insect growth and development is the process of metamorphosis. The insect cuticle (skin) is a rigid or semi- rigid body covering that provides protection and support but limits growth. In order to increase in size or change form, an insect must shed its old skin and replace it with a new one through a process known as molting. Immature insects undergo two to several molts (the number dif- fers among species) that mainly result in in- creases in size. Once an immature insect is fully grown, it undergoes one or two final molts to become an adult possessing wings and mature reproductive organs. The process of develop- ment from immature to adult is known as meta- morphosis (meaning change in form). There are two main types of insect metamor- phosis, complete and gradual. In complete metamorphosis, the change in form from the im- mature stage (known as a larva) to the adult is extreme and occurs abruptly. In most cases larvae differ greatly from adults in both physical form and life style. Because the massive changes involved in complete metamor- phosis cannot be accomplished in a single molt, the fully grown larva molts first to an inter- mediate stage known as a pupa. Wings, repro- ductive structures, and other adult features begin to develop during the pupal stage. When devel- opment is complete and environmental condi- tions are appropriate, the pupa molts and emerges as an adult. Beetles, flies, lacewings, ants, bees, wasps, butterflies, and moths undergo complete metamorphosis. (See Figure 2a.) In gradual metamorphosis, the change from immature form (in most cases known as a nymph) to adult occurs gradually from molt to molt. Nymphs differ from adults mainly in their smaller size and lack of wings and repro- ductive maturity. Little rearrangement of tissues is required during the las
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Keywords: ., bookauthorillinoisnaturalhi, bookcentury1900, booksubjectinsects
