Molecular phylogeny of bark and ambrosia beetles reveals multiple origins of fungus farming during periods of global warming
Molecular phylogeny of bark and ambrosia beetles reveals multiple origins of fungus farming during periods of global warming
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DOI：
10.1186/1471-2148-12-133
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发表时间：
2012-08-01
影响因子：
3.4
通讯作者：
Cognato, Anthony I.
中科院分区：
文献类型：
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作者：
Jordal, Bjarte H.;Cognato, Anthony I.
背景：真菌养殖是昆虫中一种不寻常的生活方式，在名为“仙果甲虫”的钻木象鼻虫中已经进化了很多次。这种行为的多次发生允许通过时间，其方向性和可能的祖先状态详细比较真菌养殖的不同起源。我们测试了这些假设，代表最大的数据集迄今为止，近4 kb的核苷酸从COI，EF-1 α，CAD，ArgK，28 S，和200 scolytine taxa.Results：系统发育分析使用贝叶斯或简约的方法将根Scolytinae接近部落Scolytini和Microborus，但在其他方面表示低分辨率在较老的节点。最近的分支得到了很好的解决，包括真菌养殖的十个起源。没有随后的逆转树皮或韧皮部喂养的真菌养殖分支。真菌农业的最古老起源估计在50 Ma左右，远在Scolytinae的起源（100-120 Ma）之后。更年轻的起源包括物种丰富的Xyleborini，可追溯到21 Ma。姐妹组性状之间的独立性比较和测试表明，无论是群居幼虫喂养，也没有定期近亲繁殖的兄弟姐妹交配是强烈相关的真菌farming.Conclusion的起源：真菌农业的起源主要对应于两个时期的全球变暖的新生代，其特点是广泛分布的热带森林。因此，温暖的气候和不断扩大的热带被子植物森林似乎在成功辐射不同的真菌养殖群体中发挥了关键作用。然而，进一步的调查可能会揭示促进真菌养殖的其他生物因素。
Background: Fungus farming is an unusual life style in insects that has evolved many times in the wood boring weevils named 'ambrosia beetles'. Multiple occurrences of this behaviour allow for a detailed comparison of the different origins of fungus farming through time, its directionality, and possible ancestral states. We tested these hypotheses with a phylogeny representing the largest data set to date, nearly 4 kb of nucleotides from COI, EF-1 alpha, CAD, ArgK, 28S, and 200 scolytine taxa.Results: Phylogenetic analyses using Bayesian or parsimony approaches placed the root of Scolytinae close to the tribe Scolytini and Microborus, but otherwise indicated low resolution at older nodes. More recent clades were well resolved, including ten origins of fungus farming. There were no subsequent reversals to bark or phloem feeding in the fungus farming clades. The oldest origin of fungus farming was estimated near 50 Ma, long after the origin of Scolytinae (100-120 Ma). Younger origins included the species rich Xyleborini, dated to 21 Ma. Sister group comparisons and test of independence between traits indicated that neither gregarious larval feeding nor regular inbreeding by sibling mating was strongly correlated with the origin of fungus farming.Conclusion: Origins of fungus farming corresponded mainly with two periods of global warming in the Cenozoic era, which were characterised by broadly distributed tropical forests. Hence, it seems likely that warm climates and expanding tropical angiosperm forests played critical roles in the successful radiation of diverse fungus farming groups. However, further investigation will likely reveal additional biological factors that promote fungus farming.