by Andreas Neuman, CEO

Published on July 27, 2023

Insects are the most diverse and abundant group of animals on the planet, with over a million species known to science. One thing that they have in common though is that they all undergo a process called metamorphosis, which involves a series of developmental stages before reaching adulthood. There are two types of metamorphosis in insects: complete (Holometabolous) and incomplete (Hemimetabolous).

 

Complete metamorphosis involves four distinct stages: egg, larva, pupa, and adult. The egg stage is the starting point, and the female insect lays eggs on or near their food source. The eggs then hatch into larvae, which consume large amounts of food, often feeding on other insects or plant material. After a period of growth, the larva enters the pupal stage, during which they transform into the adult form. During the pupal stage, the insect is dormant and does not eat. Finally, the adult insect emerges from the pupal case and begins to feed on nectar, pollen, or other sources of sugar. The adults of predatory insect species may also eat other insect species.

 

In contrast, incomplete metamorphosis has three stages: egg, nymph, and adult. Nymphs are similar in appearance to adults but lack wings and reproductive organs. During this stage, they continue to feed and grow until they reach adulthood. The adult stage begins when the nymph develops wings and reproductive organs and emerges as a fully-formed adult.

Vine mealybug infestation on a grape cluster

Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult).

Hemimatobolism, also called incomplete metamorphosis, is the mode of development of certain insects that includes three distinct stages: the egg, nymph, and the adult stage, or imago.

In some cases, there can be multiple juvenile stages before the pupal stage. These are often referred to as instars, and each instar represents a developmental stage where the insect undergoes a molt and sheds its outer skin. The number of instars can vary between species, and each instar typically involves a period of feeding and growth.

 

Beneficial insects, such as ladybugs and lacewings, feed on other insects, making them valuable for pest control in agriculture and natural ecosystems. Incomplete metamorphosis species generally feed on pests during the nymph stage, whereas complete metamorphosis species consume the majority of their food during the larval stage. Environmental conditions such as temperature and humidity can affect how much insects eat and how quickly they mature and reproduce. Higher temperatures and humidity levels typically result in faster growth rates and earlier mating and reproduction. However, extreme temperatures or humidity can be harmful to insects.

 

Understanding the different stages of insect metamorphosis is essential for pest control, conservation efforts, and the study of insect evolution. Beneficial insects can be particularly useful for natural pest control, and understanding their life cycles can help us create suitable habitats to support their populations. Additional releases of commercially available beneficial insects can also aid in pest management, and those releases often can target pests at their most vulnerable life stages – sometimes by choosing between one or more available life stages of the beneficial insect.

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