Pollination from invasive dandelions is unlikely to reduce seed production in the native Japanese dandelion, Taraxacum japonicum

摘要

Reproductive interference occurs when closely related species interact reproductively, affecting the fitness of either or both species. Understanding the mechanisms by which reproductive interference reduces fitness can be crucial for effective management and the interpretation of the functional significance of traits. Invasive apomictic dandelions reproductively interfere with the seed production of Taraxacum japonicum, a sexual species native to part of the Japanese archipelago. The simultaneous deposition of both apomictic and conspecific pollen on the stigma of T. japonicum has been hypothesised to lead to interspecific fertilisation, producing empty seeds. However, experimental results appear to vary across studies. The invasive apomict is often assumed to be T. officinale, but other apomicts are morphologically similar to T. officinale, and only some may reproductively interfere with T. japonicum. Here, hand pollination experiments were performed using potted plants to control the identities of apomictic dandelions. No evidence was found for a negative effect of apomictic pollen on T. japonicum. Based on my experimental results and the review of relevant previous studies, I concluded that the simultaneous deposition of apomictic and conspecific pollen likely leads to a normal level of seed production in T. japonicum, suggesting that mechanisms other than interspecific pollen competition for fertilisation underlie reproductive interference by apomictic dandelions on T. japonicum.