Ambrosia Beetle

Nutritional Symbiosis

Like most insects, the female Ambrosia beetle is larger than the male. Ambrosia Beetles are typically dark reddish brown with a hunched-back appearance. The larvae are white, legless, C-shaped,and indistinguishable from other scolytids.

These Beetles are known to attack various trees and shrubs, including pecan, peach, plum, cherry, persimmon, oak, elm, sweet gum, magnolia, fig, buckeye, and sweet potato.

Adults and larvae bore into twigs, branches or small trunks of host plants. They then excavate a system of tunnels in the wood and introduce a symbiotic ambrosial fungus. This fungus then provides food for the beetle. This fungus however damages and clogs the xylem, ultimately killing all or part of the plant.

They usually display year-round activity, but most activity has been observed in March. The adults follow the typical pattern of arthropods. This pattern is that they mate, lay eggs, and start it all over again.

To get rid of an infestation, the plants should be removed and burned. Insecticides can reduce infestations, but can require multiple treatments and several weeks of time.

Types of Symbiosis

Mutualism Both organisms benefit
Commensalism One organism benefits and the other organism isn't harmed
Parasitism One organism benefits at the expense of the other organism
Competition Neither organisms are benefited
Neutralism Neither organisms are affected

Nutritional Symbiosis

In our case of the Ambrosia Beetle and the Ambrosial fungus, the fungus provides food for the beetle, while the beetle provides a safe environment for the fungus. They accomplish this by the beetle boring holes into a plant and secreting the fungus. This burrow in the plant gives the fungus a perfect environment to live. While the fungus lives peacefully, it feeds the Ambrosia beetle. However the boring and the fungus end up killing the plant, which normally would cut off the food supply for the fungus causing it to die. Instead of letting this happen the beetle picks up the fungus and moves it to another spot. This gives the two organisms a mutualisic relationship.