Mycangium

The term mycangium (pl., mycangia) is used in biology for special structures on the body of an animal that are adapted for the transport of symbiotic fungi (usually in spore form).

This is seen in many xylophagous insects (e.g. horntails and bark beetles), which apparently derive much of their nutrition from the digestion of various fungi that are growing amidst the wood fibers.

In some cases, as in ambrosia beetles (Coleoptera: Curculionidae: Scolytinae and Platypodinae), the fungi are the sole food, and the excavations in the wood are simply to make a suitable microenvironment for the fungus to grow.

In other cases (e.g., the southern pine beetle, Dendroctonus frontalis), wood tissue is the main food, and fungi weaken the defense response from the host plant.

The structures of mycangia always resemble a pouch or a container, with caps or a small opening that reduce the possibility of contaminants from outside.

[14] Mycangia of bark and ambrosia beetles (Curculionidae: Scolytinae and Platypodinae) are often complex cuticular invaginations for transport of symbiotic fungi.

[7] These mycangia are often equipped with glands secreting substances to support fungal spores and perhaps to nourish mycelium during transport.

Then when females deposit their eggs inside the host plant, they inject the symbiotic fungi from mycangia and phytotoxic mucus from another reservoir-like structure.

Females of the leaf-rolling weevil in the genus Euops (Coleoptera: Attelabidae) store symbiotic fungi in the mycangia, which is between the first ventral segment of the abdomen and the thorax.

[22][23][24] A female everts the mycangium for the first time soon after eclosion; this is to retrieve the symbionts left by the larva on the pupal chamber when it emptied its gut before pupating.