T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Cordyceps and Beauveria (Vegetable insects)

Division: Ascomycota
Class: Sordariomycetes
Order: Hypocreales
Family: Cordycipitaceae
Genus: Cordyceps and Beauveria
Common names: Zombie fungus.

Fungi in the genus Cordyceps and Beauveria mostly are endoparasitoids fungi which produce the so-called “vegetable caterpillars,” “vegetable wasps,” etc., which are insects that have been attacked by these fungi and their tissues have been replaced by the vegetative portion of the attacking fungus. Some are host specific and have evolved to infect only a single species, others have many hosts

When this fungus attacks a host, it releases mycelium, which is the vegetative part of a fungus. This invades and eventually replaces the host tissue. Initially, it causes a change in the behaviour of the host causing it to climb up a trunk or a branch where it attaches itself before it dies. Gaining height ensures that the released spores will have the maximize wind distribution. Once the host is in position, the mycelium then forms a fruiting body, usually a cylindrical, branched or complex projection, which emerges through the exoskeleton of the host. The asexually produced spores are released at the tip of a specialised hypha (fruiting body). These spores are very potent, and this killer fungus can wipe out entire colonies of insects

In New Zealand, the Vespula species of wasps are common hosts of the species Beauveria malawiensis. At sites in Nelson and the Bay of Plenty large numbers of wasps were observed killed by this species of fungi. It is thought that this fungus has a great potential as a biocontrol of the Vespula species of wasps

It is interesting that one compound derived from these parasitic fungi is ciclosporin which is useful in organ transplants as it suppresses the immune system.

Below is an interesting photo of a Common wasp (Vespula vulgaris) invaded by an endoparasitoid fungus. Notice the droplet of honeydew produced by a small-scale insect that lives within the bark of beech trees (Nothofagus spp.).
Click image to enlarge then click again to enlarge further.




 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/