Ciarle Riccardo, de Bock Katrijn, Burns Kevin C
Te Kura Mātauranga Koiora, School of Biological Sciences, Te Herenga Waka, Victoria University of Wellington, Wellington, Aotearoa, New Zealand.
PLoS One. 2025 Aug 1;20(8):e0329099. doi: 10.1371/journal.pone.0329099. eCollection 2025.
Many animals live in cooperative groups comprised of morphologically differentiated individuals that subdivide labour to help the group persist in harsh, unpredictable environments. Recently it has been shown that a colonial fern from Australasia, Platycerium bifurcatum (Polypodiaceae), sub-divides labour similarly, with individuals producing morphologically different fronds depending on their vertical position within the colony. The genus contains approximately 18 taxa, which range from solitary to colonial. Whether other Platycerium species exhibit similar morphological differentiation remains poorly understood, and the evolutionary origins of coloniality along with its life-history correlates across the genus remain unknown. Here, we use ancestral state reconstruction to explore the evolution of coloniality and morphologically differentiated division of labour in the genus Platycerium. We found coloniality to be likely ancestral in Platycerium, with the condition being lost twice across the phylogeny. Eight Platycerium species exhibited colonies with morphologically differentiated individuals. This condition is derived and likely evolved twice within the genus. Coloniality was also negatively correlated with nest frond length and width but was unrelated to strap frond length. Overall, results reveal the evolutionary origins and life-history correlates of coloniality across the genus Platycerium, and support a scenario in which a colonial species with morphologically variable colony members evolved gradually from a solitary species.
许多动物生活在由形态各异的个体组成的合作群体中，这些个体分工协作，以帮助群体在恶劣、不可预测的环境中生存。最近有研究表明，一种来自澳大拉西亚的附生蕨类植物，二歧鹿角蕨（水龙骨科），也有类似的分工现象，个体根据其在群体中的垂直位置长出形态不同的叶片。该属包含约18个分类群，从单株到群体生长形式都有。其他鹿角蕨属物种是否表现出类似的形态分化仍知之甚少，而且该属群体生长习性的进化起源及其与生活史的相关性也尚不清楚。在此，我们运用祖先状态重建法来探究鹿角蕨属群体生长习性以及形态分化分工的进化过程。我们发现群体生长习性在鹿角蕨属中可能是祖先状态，这种状态在系统发育过程中丧失过两次。八个鹿角蕨属物种表现出具有形态分化个体的群体。这种状态是衍生而来的，并且可能在该属中独立进化了两次。群体生长习性也与巢状叶的长度和宽度呈负相关，但与带状叶的长度无关。总体而言，研究结果揭示了鹿角蕨属群体生长习性的进化起源及其与生活史的相关性，并支持了一种假说，即具有形态可变群体成员的群体物种是从单株物种逐渐进化而来的。
