Bang! I was inspired to photograph this alpine yucca after Judy Newton, UBC Botanical Garden‘s soon-to-be-retiring education coordinator, featured it in a lecture on Tuesday. Despite being native to New Mexico and Arizona, this plant does quite well in our well-drained alpine garden. Not the typical sort of plant one expects to see in Vancouver!
Yuccas have only one group of pollinators: yucca moths. The two sets of organisms have a special kind of relationship called obligate mutualism, in which both organisms benefit from each other, and indeed rely on each other–if one were to go extinct, the other would follow.
The yucca moths are highly specific pollinators for the yucca (not just any insect will do!), so they are necessary if seed production is going to occur. While pollinating the flowers, the yucca moths also lay their eggs. The hatched moth larvae are picky eaters, only feasting on developing yucca seeds (and leaving quite a few behind to germinate into new yucca plants). In short, no yucca seeds, no yucca moths. No yucca moths, no yucca seeds.
If you’re interested in further reading on the topic, I’d suggest reading Tegeticula, the yucca moths from The Tree of Life Project, as well as the web page of Dr. Olle Pellmyr from the University of Idaho. Dr. Pellmyr has published a paper asserting that there is evidence to believe that the yucca-yucca moth obligate mutualism relationship has existed for forty million years.
In other news, the latest edition of Tangled Bank (link now defunct) is out: Tangled Bank #30 via The Geomblog. Tangled Bank is (was) a “gathering of science weblogs” that promotes the best science weblog writing on a bi-weekly basis (and now switching to weekly). The Botany Photo of the Day submission for this edition was the entry on Raoulia australis, since I figured a shape-heavy photograph would have at least a little relevance to a weblog devoted to computational geometry.