Species Facts:

Oak Ambrosia Beetles, platypus quercivorus, in combination with its associated ambrosia fungus Raffaelea quercivora, are capable of causing extensive tree mortality in oak forests dominated by Quercus mongolica and Q. serrata. This could result in major environmental impacts such as loss of biodiversity, changes in species composition of forests, reduced acorn crops and resultant adverse impacts on wildlife species that depend on acorns as a food source.
Male Oak Ambrosia Beetles initiate attacks on the boles of host trees and excavate galleries for mating from June to October. Apparently the first entry holes bored by male beetles trigger a mass attack, which generally occurs near ground level. A single female joins the male and, after mating, constructs the oviposition gallery, which is kept clean by the male by expelling the residues to the outside of the tree. During gallery construction, females inoculate the gallery surface with spores of the ambrosia fungus on which the larvae feed. Adult females began to deposit eggs at the terminal parts of tunnels two to three weeks after the beginning of gallery construction.

Eggs are deposited in individual niches. An average of 50 to 60 larvae develop in a single gallery system but the number of larvae can be as high as 161. Pupation occurs in the larval galleries. The majority of new adults leave their maternal galleries in September and October, but some adults remain in the galleries until spring and then die. In other cases larvae reach the 5th instar by late November and overwinter in pupal chambers. Pupation begins the following May, and adults emerge in June and July. Adults emerge through entry holes made by the parent adults.

Direct damage caused by Ambrosia Beetles is associated with galleries constructed in the wood of host trees during breeding attacks. This can result in loss of structural integrity of the wood and loss of lumber quality.

Life Stages & Descriptions:

Eggs are elongated and cylindrical. Larvae are variable in size, ranging from 2-6 mm in length when mature. They are legless, creamy white in color with an amber to light brown colored head capsule. The last abdominal segment ends in a flat to slightly concave declivity. The pupae are creamy white in color and have partially developed wings and appendages.

Adults of the genus Platypus are reddish brown to dark brown in color with a cylindrical, elongated body that averages 5 mm long. These insects have a concave declivity armed with spines. The front (prothoracic) legs are adapted for excavation.

Adults are capable of sustained flight of at least 1 km and are also subject to dispersal by air currents. All life stages are subject to human assisted dispersal. Use of crating, pallets or dunage made from oak in international trade could result in the intercontinental spread of all life stages of Ambrosia Beetles. Localized spread of newly established infestations could be facilitated via the transport of logs and firewood.

Portions of this article courtesy of: EXFOR Database
Image of an Oak Ambrosia Beetle (Photo from: www.bugwood.org Credit to: E. Richard Hoebeke)