The corpus allatum in insect physiology

Insect physiology

Insect physiology includes the physiology and biochemistry of insect organ systems.Although diverse, insects are quite similar in overall design, internally and externally...

, is an endocrine gland which generates juvenile hormone

Juvenile hormone

Juvenile hormones are a group of acyclic sesquiterpenoids that regulate many aspects of insect physiology. JHs regulate development, reproduction, diapause, and polyphenisms....

; as such, it plays a crucial role in metamorphosis. Surgical removal of the corpora allata (an allatectomy) can cause an immature larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

 to pupate at its next molt, resulting in a miniature adult. Similarly, transplantation

Organ transplant

Organ transplantation is the moving of an organ from one body to another or from a donor site on the patient's own body, for the purpose of replacing the recipient's damaged or absent organ. The emerging field of regenerative medicine is allowing scientists and engineers to create organs to be...

 of corpora allata from a young larva to a fully mature larva can greatly extend the larval stage, resulting in an equivalent to gigantism

Gigantism

Gigantism, also known as giantism , is a condition characterized by excessive growth and height significantly above average...

.

In many Diptera

Diptera

Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...

 species, the corpus allatum is fused with the corpus cardiacum, forming a "ring gland", also known as Weismann

August Weismann

Friedrich Leopold August Weismann was a German evolutionary biologist. Ernst Mayr ranked him the second most notable evolutionary theorist of the 19th century, after Charles Darwin...

's ring.

In Lepidoptera

Lepidoptera

Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...

 species, the corpus allatum acts a release site for prothoracicotropic hormone

Prothoracicotropic hormone

Prothoracicotropic hormone was the first insect hormone that was discovered. It was originally described simply as "brain hormone" by early workers such as Stefan Kopeć and Vincent Wigglesworth , who realized that ligation of the head of immature insects could prevent molting or pupation of the...

which is generated by the brain.