Ecology and evolution of insect-fungus mutualisms

Authors: BIEDERMANN, P - University Of Wurzburg; Vega, Fernando

Submitted to: Annual Review of Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2019
Publication Date: 10/14/2019
Citation: Biedermann, P.H., Vega, F.E. 2019. Ecology and evolution of insect-fungus mutualisms. Annual Review of Entomology. 65:431–455.

Interpretive Summary: Many insects and fungi have evolved beneficial partnerships known as mutualisms. One of the best-known insect-fungal mutualisms involves important insect pests of forests known as bark beetles, with ants and termites being also well known. We have individually analyzed the types of mutualisms (nutrition, mechanical defense, antimicrobial defense, and dispersal) and classified them according to the benefit they confer to specific insects and fungi. This information will be of use to entomologists, ecologists and mycologists studying insect-fungus associations, including pest managers combating invasive insect species.

Technical Abstract: The evolution of a mutualism requires reciprocal interactions whereby one species provides a service that the other species cannot perform or performs less efficiently. Services exchanged in insect-fungus mutualisms include nutrition, defense, and dispersal. Fungi can be consumed by insects or can degrade plant polymers or defensive compounds, thereby making a substrate available to insects. They can also protect against environmental factors and produce compounds antagonistic to microbial competitors. Insects disperse fungi and can also provide fungal growth substrates and protection. Their mutualisms can transition from facultative to obligate, whereby each partner is not viable on its own anymore. Obligate dependency has (i) resulted in the evolution of morphological adaptations in insects and fungi, (ii) driven the evolution of social behaviors in some groups of insects, and (iii) led to the loss of sexuality in some fungal mutualists.