Observations on phenology and pollination of Triphora trianthophora (three-bird orchid) made during the summer of 2019

This post is a modified article that was originally published in the Webster Groves Nature Study Society’s journal, Nature Notes (January, 2020, Vol. 92, No. 1).

Finding the orchid, Triphora trianthophora (three-bird orchid, nodding pogonia), during open bloom can be somewhat of a chore, particularly among us weekend warriors. Casey Galvin and I were both intrigued about the possibility of getting photographs of this diminutive and gorgeous orchid since learning of their discovery at Babler State Park by the WGNSS Botany Group led by Nels Holmberg, John Oliver and others in 2018. The following descriptions and photographs are anecdotal and were not collected using rigorous scientific methodology.

Phenology

There are several reasons it is challenging to find this extremely ephemeral plant in bloom. First, being partially saprophytic, the plants exhibit periodic dormancy and may not send up above-ground shoots every year, persisting instead as subterranean tubers for extended periods (Homoya, 1992). Even when they do produce stems and leaves, there is no guarantee the plants will flower in a given year. Additionally, when they do flower, any one bloom is open for only a few hours during a single day.

Exhibiting a phenomenon known as thermoperiodicity, a group or population of these plants are synchronized to open mature buds on the same day. This first wave of synchronous blooming is reportedly induced by a drop in minimum daily temperature of at least three degrees over two or more consecutive days. Following another 48-hour period, all mature buds within the population will then open on the same day (Luer 1975). Being skeptically minded, this was something I wanted to observe for myself.

Beginning in late July, Casey and I began monitoring the easier to get to population at Babler State Park. The first wave of synchronous flowering occurred on August 3rd. We unfortunately missed this but know the exact date because of visits on days immediately before and after this date. Looking into historical temperatures collected from the closest publicly-available weather station (Babler Park Estates – KMOBALLW37) revealed the initial blooming date fit the required temperature pattern perfectly (see attached figure). I continued monitoring and collecting flowering data and observed two more large flushes of synchronized blooms along with three days interspersed where only 3–10 stems/plants opened flowers. For subsequent synchronized days, I did not observe a coinciding drop in temperature as described above. I assume that the trigger for the initial bloom works to synchronize the population and subsequent larger bloom days are consequently synchronized due to all plants ‘running ahead’ at the same rate. However, there could potentially be some other unknown environmental triggers that are playing a hand here.

The first synchronous bloom occurred on August 3rd, approximately 48 hours following a four-day drop of approximately seven degrees in minimum daily temperature. Data collected from https://www.wunderground.com/ accessed on 12/06/2019.
No longer “nodding”. Triphora trianthophora flowers open towards the sky en masse on just the right day. Photo by Bill Duncan.
Arrive a day too late and this will be what you find. Photo by Casey Galvin.
Much like the flowers, these developing pendulous seed capsules will become erect at maturity. Photo by Bill Duncan.

Pollination

Halictid bees have been reported to be the primary pollinator for this species (Luer 1975). I had this in mind as I observed and began taking photographs while visiting on a large bloom day but doubted I would be fortunate enough to observe or photograph a potential pollinator visit. However, patience allowed me to do just that. I first observed visits by small flies and Bombus impatiens. Although Williams (1994) reported that Bombus have acted as pollinators of this species, I did not observe any of these visitors with attached pollinia during the 10-15 flowers I watched them visit. Eventually, I observed three different Halictid bees as they visited multiple flowers and observed these were heavily attached with pollinia. As described by Williams (1994), seed capsule production (successful pollination) is a relatively rare event in this species. Nevertheless, this was a treat to observe and photograph.

Nectar thieving flies and developing buds can be seen along with an open flower. Photo by Casey Galvin.
Like a hand to a glove… This halictid bee (Augochlora pura) does not yet realize the burden it will be asked to take in exchange for sweet nectar. Photo by Bill Duncan.
Removing itself along with attached pollinium requires some gymnastic effort. Photo by Bill Duncan.
Removing itself along with attached pollinium requires some gymnastic effort. Photo by Bill Duncan.
If you had to make this bee anymore attractive? Augochlora pura with attached colorful Triphora trianthophora pollinium. Photo by Bill Duncan.
Bees in the genus Bombus have been described as active pollinators of Triphora trianthophora. I watched several B. impatiens each visit multiple flowers and observed no attached pollinia. Photo by Bill Duncan.

REFERENCES

Homoya, M.A. Orchids of Indiana. Indiana University Press, Indianapolis, Indiana, USA.

Luer, C.A. 1975. The Native Orchids of the United States and Canada. New York Botanical Garden, Bronx, New York, USA.

Williams, S.A. 1994. Observations on reproduction in Triphora trianthophora. Rhodora 96:30-43.

Tragidion coquus – Second Time!

Tragidion coquus female photographed at Hughes Mountain Natural Area, Sep. 28, 2019.
f/18, 1/30 sec., ISO-400, 234 mm focal length equivalent

For the second year in a row, a special beetle that has been described by our own Ted MacRae as “one of the rarest and most beautiful species of longhorned beetle to occur in Missouri” was found during the joint field trip of the WGNSS Entomology and Nature Photography groups at Hughes Mountain Natural Area. Tragidion coquus, purported to be spider wasp mimics, mine in dead oak branches and can be found in flight between June and November.  I wasn’t happy with my photos of last year’s specimen (also a female), so I was thrilled to be able to take the time and set her on some foliage with fall colors. It was an almost disaster as she was able to take flight before we were finished. But, having the quick reflexes of a Marvel superhero, I was able to catch her out of the air with a quick grab with just a slight kink in her antennae in consequence.

Tragidion coquus female photographed at Hughes Mountain Natural Area, Sep. 28, 2019. f/14, 1/60 sec., ISO-400, 234 mm focal length equivalent

 

Return to Vilander Bluff

Autumn View of Vilander Bluff
f/11, ISO-160, 32 mm focal length, three exposure blend of 1/60, 1/15, 1/4 sec.

I had a great time introducing some photographer friends of mine to one of my favorite places in the state, Vilander Bluff. With the largest bluffs on the Meramec River, to get the type of view seen here requires a little bit of effort. Dave and I put in some work in finding this new-to-me perspective that was well worth the bit of effort and risk. Next time we’ll need to bring climbing ropes…

Blazing Maple
f/5.6, 1/6 sec., ISO-1250, 45 mm focal length

First Merlin of the Season!

Merlin, RMBS
f/8, 1/1600 sec., ISO-640, 1600 mm focal length equivalent

A trip to Riverlands Migratory Bird Sanctuary last weekend paid off. I crossed paths with this juvenile Merlin, my first of this season, three different times. In this instance I had my camera prepared. He kindly perched long enough that I could swap for the 2X teleconverter. I think the 2X performed pretty well in this perfect light, but heat distortion was a major problem on this cool but sunny day.

Perched Merlin
f/10, 1/800 sec., ISO-500, 1600 mm focal length equivalent

Wallen Creek Shut-ins

Wallen Creek Shut-ins. Getting it all in.
f/14, 1/2 sec., ISO-200, 29 mm focal length.

Many thanks to Casey Galvin tracking this one down and to the property owners allowing us access.

Wallen Creek Shut-ins.
f 5.6, 1/10 sec., ISO-100, (0 mm focal length.

Wallen Creek Shut-ins.
f/11, 1/2 sec., ISO-125, 90 mm focal length, vertical stitch of three images.

Wallen Creek Shut-ins
f/8, 1/5 sec., ISO-160, 90 mm focal length.

Wallen Creek Shut-ins swirling
f/14, 15 sec., ISO-200, 19 mm focal length.

Missouri Orchids – Spiranthes lacera (slender ladies tresses)

Spiranthes lacera, St. Francois Co, MO. f/16, 1/50 sec., ISO-640, 234 mm focal length equivalent

I only managed to photograph one of the Spiranthes this year. I had opportunities for others, but I just couldn’t get to the right place at the right time. Good news is that it shouldn’t be too difficult to add them next year.

Spiranthes lacera, St. Francois Co, MO. f/16, 1/60 sec., ISO-640, 234 mm focal length equivalent

A bit closer really shows off the delicate details in flower and twisting stem.

Spiranthes lacera with passenger, St. Francois Co, MO. f/16, 1/50 sec., ISO-640, 234 mm focal length equivalent

Dashing Blue Dashers

Blue Dasher (Pachydiplax longipennis) – f/8, 1/160 sec., ISO-200, 520 mm focal length equivalent

Blue Dasher (Pachydiplax longipennis) – f/8, 1/200 sec., ISO-160, 520 mm focal length equivalent

Blue Dasher (Pachydiplax longipennis) – f/8, 1/160 sec., ISO-200, 520 mm focal length equivalent

Blue Dasher (Pachydiplax longipennis) – f/11, 1/160 sec., ISO-320, 520 mm focal length equivalent