Hybridization — are generalist pollinators the key to success?

I’ve been on a bit of a rant lately concerning hybridization in plant species complexes, which recently resulted in my last post suggesting hybridization could be a potential ‘solution’ to the problem of an ever-changing climate. I want to dig a little deeper now and ask the questions — can generalist pollinators have anything to do with the maintenance of a generalized floral form in Claytonia? If so, can this indirectly act as a selective force for increased hybridization among distantly (and closely) related species? If you have seen the ‘face shots’ from a recent ‘Spring Beauty Pageant‘ than you know what I’m talking about. Maybe you’ve even suggested to a friend, because Claytonia grow like weeds where you are from, that you believe there to be little variation in floral form among species in the genus. I’d agree with you, to a certain extent… but then again, maybe there is so much intra-population variation in floral morphology (coloration, petal shape) that we are blind to see the true pattern of differentiation in floral form among closely related taxa. I’ve touched upon the subject of within-population variation of the flowers of one member of the C. “peirsonii” complex from the southern Sierra Nevada, but now I want to expand on this subject with photographs taken within a single population of C. lanceolata sensu lato on the Great Continental Divide in Montana. As you can easily tell from the first picture below, in which all of the white spots are Claytonia flowers, it is not difficult to conduct this sort of ‘experiment’ yourself. In other words, it is easy to get a lot of face-on photographs of Claytonia flowers because they occur in extremely dense populations. This spring, try to see how much your favorite Claytonia varies in its floral form — you may be surprised at what you find!IMG_8497IMG_8570IMG_8449IMG_8582 IMG_8453IMG_8458IMG_8477IMG_8478IMG_8531IMG_8547IMG_8516     Keep in mind that all of the above pictures are of plants that occur in a single population of C. lanceolata sensu lato on the Great Continental Divide in Montana. As evidenced by the last photograph, even merosity can go haywire from time to time. If I showed you just that last picture, you might even confuse the plants for Lewisia. That is a lot of variation! Are these hybrid plants of C. lanceolata (which has retuse petal apices) crossed with another species in the area with entire petals? Good question! Let me get back to you on that one…

All I know is that multiple Claytonia species can occur in sympatry, and intermediate forms can be found in those areas. This is especially true of the annual species of Claytonia. I haven’t observed putative hybrids among the annuals (i.e., the miner’s lettuces) and tuberous perennials (i.e., C. lanceolata species complex), although I have observed them sharing pollinators in southern California. Pictured below are soft-wing flower beetles (Melyridae) visiting both C. rubra (section Limnia, first picture below) and C. “peirsonii (section Claytonia, second picture below) at the same location on the same day in the southern Sierra Nevada, California. You might remember from one of my very first posts: these pollen eaters are quite effective pollinators.

IMG_5457 IMG_5402Too many questions for a single dissertation to address, but I’ll see what I can do! 😉

Advertisements

Floral morphology in Claytonia: How much variation is ‘normal’ for a species?

Ok, so you may remember this recent post, where I asked for interested people to send me pictures of as many flowers as they could photograph…

The premise is simple: How much variation is considered the ‘normal’ or ‘typical’ amount of variation for a species? How much is typical in terms of petal shape, size, and color for individuals in a given population of tuberous perennial Claytonia?! My collaborators and I have noticed quite a bit of variation among populations of different species, but what may be even more interesting is the amount of variation within populations. It might bend your brain the next time you kneel down and take a look around at the tuberous perennial Claytonia blooming in your area (right now!!!)… Better yet, take a picture of 50-100 different flowers from directly facing the flowers (trying to center the gynoecium in the flower as best as possible). Compare all your photos, or send them my way. We’ll get to the bottom of this!

Enter stage left as ‘proof of concept’, a member of the C. “peirsonii” complex from the southern Sierra Nevada — all of the below pictures are from different flowering individuals within a single population, taken on the same day within about 45 minutesIMG_5421 IMG_5418  IMG_5404Note the visitors above: an ichneumonoid wasp (likely a parasitoid braconid) on the left, and a soft-winged flower beetle (Melyridae) on the right. We saw these same beetles last year, and I’ve also mentioned them in the ‘who’s pollinating Claytonia?‘ series — special thanks to Dr. Emile Fiesler for help with the identifications!IMG_5432IMG_5398IMG_5382IMG_5387IMG_5324IMG_5331IMG_5396The variation is crazy, right?!

IMG_5340I really need to get a new ‘cutest Claytonia‘ contest going soon…