Addendum to last post: Orchid/moth photo safari

My orchid-pollinating moth rig stands ready. In my last post, I shared photos of the beautiful albeit elfin Small Green Wood Orchid (Platanthera clavellata). As noted in that post, this orchid species has been shown to be largely or at least partially self-pollinating, but insect pollinators surely visit, at least on occasion. At least one known hybrid makes that clear. Well, I couldn't stop thinking about this and was eager to try to see if any moths - the most likely pollinators by far - might visit these orchids. As the pair of plants that I shared in the last post were quite large for this species, and in perfect condition, I decided it was now or never (at least until next year).

So off I went last evening, arriving at the west-central Ohio locale shortly before dusk. Moth pollinators are often crepuscular, visiting flowers at dusk or soon after. See THIS POST for an example of a similar hunt in which I met with success.

The photo above shows my camera rig, set up and ready to fire and affixed to my Gitzo tripod. It is pointed and focused on the orchids, which are near the base of the trees. It's a Canon R5 mated to a Canon 400mm f/2.8 II lens, coupled to a 50mm extension tube. That gets the minimum focus down to about six feet. A Canon 600 speedlite provides illumination, and it's equipped with a Better Beamer flash extender. That unit's fresnel lens magnifies the flash output, allowing light to be thrown further - a necessity when shooting fast shutter speeds in high-speed sync mode. Settings were 1/1000, f/8, and ISO 1000, which gave a good exposure in very dark conditions.

Here's a shot of my target, the lush inflorescence of a Small Green Woodland Orchid. Note the luminescent greenish/whitish/yellowish flowers with greatly elongate nectar spurs. These features strongly suggest moths as pollinators.

Conditions were perfect: absolutely no wind, warm, and humid. As evidence of the stillness, I made the above shot without flash - it was nearly dark - at f/18, ISO 200, and a whopping 13 second exposure. Try that with even the slightest breeze. I generally do not care for the look of flash on flowers. It can impart a harshness not in keeping with the subject's qualities. But when shooting fast-moving moths at flowers, in the dark, flash is essential.

What I would have given to have had a moth in a shot with the orchid. Alas, it was not to be.

A big female fishing spider in the genus Dolomedes was one companion on my nocturnal vigil. She carries her egg sac underneath her body, and the tarantula-sized spider is a formidable defender of her spawn.

As dusk darkened into true night, more creatures of the night emerged. Such vigils, even if "unsuccessful" regarding the goal, are always interesting. Early on I had a moment of hope when some smallish sphinx moth rocketed in and began pollinating nearby Spotted Phlox (Phlox maculata). It got within ten feet of the orchids and I had great hopes it would visit them. No go. As it got darker, ever more moths began flying, but none displayed interest in the orchids.

I packed it in a bit after 10:30 pm, but not before being treated to many interesting creatures of the night. A big old Raccoon came ambling down the trail, got within ten feet of me, and decided to do an about face and reverse course. A pair of Great Horned Owls duetted back and forth at close range, the deeper more resonant hoots of the male alternating with the female's higher pitched hooting. I later saw one of the birds atop a phone pole in my headlights on the way out. A Barred Owl screamed repeatedly at one point, which triggered a classic Who-cooks-you, all! response from its mate. A steady chorus of frog-like chirps came from nearby Northern Mole Crickets. The strange orthopterans are mostly subterranean and even sing from within their burrows. The walk out involved traversing a wet meadow, which was full of the amusingly named Slightly Musical Conehead, their rough "songs" the most conspicuous sound in the damp field.

I don't know if I'll get around to going for moths at Small Green Wood Orchid again. Such a photo would certainly be a challenge. Because of the plant's ability to self-pollinate, perhaps not many insect pollinators visit. Or maybe moths tend to come to the flowers in the wee hours, or just prior to dawn or in the early morning hours, as in THIS CASE. Trying for photos such as this can involve a lot of luck, a lot of time, or more likely a bit of both.

Small Green Wood Orchids

A pair of Small Green Wood Orchids (Platanthera clavellata) in perfect flower on a mossy tree base. The larger one towered to about 6-8 inches in height. Not much is known about its pollination biology, but moths are almost certainly the pollinators. These plants are in a west-central Ohio woodland, about 45 minutes west of Columbus. I made these images yesterday afternoon.

This little orchid is scattered in small populations, and rather rare from my experience. But it is certainly overlooked. Platanthera clavellata flowers in shady haunts in the heat of mid-summer, and such habitats probably are not as well botanized as they should be at that season. Mosquitoes help to drive botanists from such sites, along with the heat and humidity.

A close-up of the inflorescence, which is heavily laden with tiny flowers in perfect condition. Note the luminescent whitish cast to the flowers, and long tubular nectar spurs. Both features select for moths. But which moths? Well, the mystery thickens. The great botanist Asa Gray was the first person to figure out that P. clavellata is at least partially self-pollinating. Pollen germinates within the pollinia (pollen sacs) and then grows downward into the stigma (female receptacle).

That said, this orchid's flowers are tailor-made for moth pollination. The luminescent greenish-white color would be highly visible in darkness, and those very long nectar spurs (the slender tubes trailing from the flowers) are typical of orchids that favor pollination by moths with long probosci. Furthermore, there is at least one known case of hybridization. The great orchidologist Fred Case, at the University of Michigan, found a hybrid between this species and White-fringed Bog Orchid (Platanthera blephariglottis). Thus, pollinating insects must sometimes visit, and they would almost certainly be moths.

As evidence of the luminosity of the flowers, I shot these images on a bright overcast day, but the orchids were in full shade. Exposing at neutral on the meter rendered completely blown out - overexposed - images. It was necessary to underexpose by about two full stops to get a correct exposure. It's almost as if the flowers are plugged into an outlet and glowing.

If time allows, I hope to get back to these plants around dusk, and watch them into nightfall, to see if moths do visit. And if so, try to capture them on pixels and hopefully identify them. 

An orchid - 175 years later

A diminutive club-spurred orchid, Platanthera clavellata, juts from the shady gloom of the forest floor at Cedar Bog. I made these photos yesterday, and will apologize up front for their relative lack of quality. I was helping to lead a field trip for the Botanical Society of America, and didn't have time to set up these shots in the manner in which I would have preferred.

I've written about Cedar Bog many times, including several times this year. It has been a banner season for orchids at "the bog", and now the club-spurred orchid can be added to the roster. HERE IS an earlier post about Cedar Bog's showiest representative of the Orchidaceae family.

One of the botanists that was along on yesterday's field trip was the incomparable Anton "Tony" Reznicek of the University of Michigan. Tony oversees the U. of M.'s herbarium, which is one of the largest in the country and contains some 1.7 million specimens of vascular plants, algae, bryophytes, fungi and lichens. I think something like a million or more of these specimens are vascular plants, such as the orchid featured in this post.

The University of Michigan herbarium houses a number of very old and valuable collections, including some of the first plant specimens collected in the Midwest. These holdings include a series of collections from a gentleman named John Samples, who was the first botanist to make specimens from Ohio's own Cedar Bog. Samples was an Urbana school teacher, and thus lived near Cedar Bog (for a comprehensive biography of Samples, CLICK HERE). From 1836 to 1840, he made numerous collections of plants from this area, at a time when Cedar Bog and other local prairies and fens were far more extensive than they are today.

 Upon his return to Michigan, Tony Reznicek ducked into the herbarium and had a look at some of John Samples' Cedar Bog plant specimens. Lo and behold, there was a collection of club-spurred orchid, with the following label information:

"Habenaria tridentata, Orchis tridentata [old synonyms for Platanthera clavellata]. From the Upper Cedar swamp, August 12th, 1837".

So, exactly 174 years and 11 months later, I photographed this orchid in probably nearly the same spot that Samples collected it, he in the same year that Michigan became the 26th state admitted to the Union. Were it not for the conservation of Cedar Bog, I can guarantee that the club-spurred orchid and most of its neighboring botanical treasures would no longer exist in that area.

I and others are fond of saying that places like Cedar Bog are living museums; places where people can go and see habitats, plants and animals that existed back in pioneer days. The example of this little orchid bears that out.