Appl Environ Microbiol. 1997 Feb;63(2):621-7. doi: 10.1128/aem.63.2.621-627.1997.
The southern pine beetle, a damaging pest of conifers, is intimately linked to three symbiotic fungi. Two fungi, Ceratocystiopsis ranaculosus and Entomocorticium sp. A, are transported within specialized structures (mycangia) in the beetle exoskeleton and are mutualists of the beetle. A third fungus, Ophiostoma minus, is transported externally on the beetle exoskeleton (phoretically) and is an antagonist of the beetle. This study examined competitive interactions among these three fungi. The results of de Wit replacement series and primary and secondary resource capture assays with these fungi provide strong evidence for differential competition between the phoretic and mycangial fungi. O. minus was the most able to capture both uncolonized and colonized resources. Entomocorticium sp. A and C. ranaculosus, although equal to one another in competitive abilities, differed in their ability to compete with O. minus. Entomocorticium sp. A was able to maintain space free of O. minus to a much greater degree than was C. ranaculosus. The outcome of such competitive interactions may have significant impacts on the biology of this ecologically and economically important beetle.
南方松甲虫是一种危害针叶树的有害害虫，与三种共生真菌密切相关。两种真菌，Ceratocystiopsis ranaculosus 和 Entomocorticium sp. A，被运送到甲虫外骨骼中的专门结构（菌囊）中，是甲虫的共生体。第三种真菌 Ophiostoma minus 则在甲虫外骨骼上外部运输（寄生于），是甲虫的拮抗剂。本研究检查了这三种真菌之间的竞争相互作用。用这些真菌进行德维特替代系列和初级和次级资源捕获测定的结果提供了寄生物种和菌囊物种之间存在差异竞争的有力证据。O. minus 最能够捕获未定植和定植的资源。虽然 Entomocorticium sp. A 和 Ceratocystiopsis ranaculosus 在竞争能力上彼此相等，但它们与 O. minus 竞争的能力不同。Entomocorticium sp. A 能够保持更大程度的 O. minus 空间，而 Ceratocystiopsis ranaculosus 则不能。这种竞争相互作用的结果可能对这种具有生态和经济重要性的甲虫的生物学产生重大影响。
