Department of Natural History Science, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Laboratory of Ecology & Evolutionary Biology, Yunnan University, Kunming 650091, China.
Mol Phylogenet Evol. 2021 Oct;163:107257. doi: 10.1016/j.ympev.2021.107257. Epub 2021 Jul 10.
Despite numerous phylogenetic studies on the family Drosophilidae, relationships among some important lineages are still poorly resolved. An example is the equivocal position of the Zygothrica genus group that is mostly comprised of the mycophagous genera Hirtodrosophila, Mycodrosophila, Paramycodrosophila, and Zygothrica. To fill this gap, we conducted a phylogenetic analysis by assembling a dataset of 24 genes from 92 species, including 42 species of the Zygothrica genus group mainly from the Palearctic and Oriental regions. The resulting tree shows that the Zygothrica genus group is monophyletic and places it as the sister to the genus Dichaetophora, and the clade Zygothrica genus group + Dichaetophora is sister to the Siphlodora + Idiomyia/Scaptomyza clade. Within the Zygothrica genus group, the genera Mycodrosophila and Paramycodrosophila are both recognized as monophyletic, while neither the genus Zygothrica nor Hirtodrosophila is monophyletic. We also used this phylogenetic tree to investigate the evolution of mycophagy by reconstructing ancestral food habit in the Drosophilidae. We found that fungus-feeding habit has been gained independently in two lineages. The most recent common ancestor (MRCA) of the subgenus Drosophila was estimated to have acquired mycophagy by expanding its ancestral feeding niche on fermenting fruits to decayed fungi, while the MRCA of the Zygothrica genus group shifted its niche from fruits to fungi as a specialist probably preferring fresh fruiting bodies.
尽管对果蝇科进行了大量的系统发育研究，但一些重要谱系之间的关系仍然没有得到很好的解决。一个例子是 Zygothrica 属组的位置不确定，该属组主要由食真菌的属 Hirtodrosophila、Mycodrosophila、Paramycodrosophila 和 Zygothrica 组成。为了填补这一空白，我们通过组装来自 92 种物种的 24 个基因数据集进行了系统发育分析，其中包括来自古北界和东洋界的 42 种 Zygothrica 属组物种。结果表明，Zygothrica 属组是单系的，与 Dichaetophora 属并列，而 Zygothrica 属组+Dichaetophora 枝是 Siphlodora+Idiomyia/Scaptomyza 枝的姐妹群。在 Zygothrica 属组中，Mycodrosophila 和 Paramycodrosophila 两个属都被认为是单系的，而 Zygothrica 属和 Hirtodrosophila 属都不是单系的。我们还利用这个系统发育树来研究果蝇科中食菌习性的进化，通过重建果蝇科的祖先食物习性来进行研究。我们发现，食菌习性已经在两个谱系中独立获得。果蝇亚属的最近共同祖先（MRCA）被估计是通过将其祖先在发酵水果上的觅食范围扩大到腐烂真菌上，从而获得了食菌习性，而 Zygothrica 属组的 MRCA 则将其从水果到真菌的生态位转移为专食者，可能更喜欢新鲜的真菌体。
