Platanthera lacera [pollination & insect interaction]
This mosquito was observered apperently eating pollen [pollina] contained inside the anther sac on Platanthera larcera. Schuylkill County, Pa. July 2023.
A Thrip feeding on Platanthera lacera. Schuylkill County, Pa.
Tarnished Plant Bug [Lygus lineolaris] on Platanthera lacera. Schuylkill County, Pa. 7-3-23
Waiting in the dark at midnight to see pollinators [moths] of Ragged fringed Orchid [Platanthera lacera]. Schuylkill County, Pa. 7-3-23. After three nights I never did see anything but found it very exciting. Oddly enough of the four plants in the area, this was was the only plant that now shows signs of a few of the flowers being pollinated [swollen ovaries] . On one occasion getting there before dark to set up for the wait, there was a moth seen briefly at this particular flower, no doubt the pollinator of some of the flowers mentioned earlier.
The swelling ovary on this Ragged Fringed Orchid flower indicates that it was pollinated successfully. This particular plant was in full bloom just 3 weeks ago. [Platanthera lacera]. Schuylkill County, Pa. 7-28-23. Of the four plants at this location, this was the only plant that any pollination occurred and less that a quarter of the flowers on this plant were pollinated. Last year in this area none of the P. lacera flowers were pollinated. It would seem that for P. lacera successful pollination is poor at best, at least in this particular area. P. lacera is pollinated at night by moths attracted by a sweet fragrance only released at night. These moths include the Hummingbird Clearwing Moth [Hemaris thysbe], Celery Looper Moth [Anagrapha falcifera] and Copper Looper Moth [allagrapha aerea]
After spending a total of 10 hours over three nights [covering a two week period] trying to capture a moth pollinating Platanthera lacera [Unspotted Cooper Moth [Allagrapha aerea] is a known pollinator], all that I have seen [so far] is this tiny unknown insect [mosquito?]. Schuylkill County, Pa. July 2023. The insect did appear to be eating the pollen [pollinia] contained inside the anther sac. [seven pictures seen above]
After spending a total of 10 hours over three nights [covering a two week period] trying to capture a moth pollinating Platanthera lacera [Unspotted Cooper Moth [Allagrapha aerea] is a known pollinator], all that I have seen [so far] is this tiny unknown insect [mosquito?]. Schuylkill County, Pa. July 2023. The insect did appear to be eating the pollen [pollinia] contained inside the anther sac.
The pollinarium having been removed from the anther sac by a moth has fallen off the moths proboscis. You can see the tiny grans of of pollen or pollinia inside the end of the pollinarium called the pollinium, the pollinia is made up of many massulae, which in turn are made up of tiny grains of pollen masses that are bound together by viscid threads.
The Incredible story of the pollination of the Ragged Fringed Orchid [Platanthera lacera] How this orchid evolved to form partnerships with moths for the continuation of its species is truly remarkable. Looking at first 1 & 2 picture you can see the orifice opening to the spur is bisected [a pallet or hood] into two distinct openings, compared to the spur opening for the Platanthera ciliaris [picture 3] which is round and not bisected [no pallet, or hood]. The insect, in the case of P. lacera a moth [Unspotted Cooper Moth [Allagrapha aerea] is a known pollinator], drawn in by fragrance is forced to one the side or the other to place it's proboscis deep into the spur to get it's sweet reward of nectar. In doing so it's tongue [proboscis] comes into contact with the viscidium and pulls out the pollinarium. The dual openings helps guide the the proboscis to one side or the other and closer to the pollinarium and better insuring of one getting attached to the proboscis by the sticky viscidium. This is in contrast to P. ciliaris, which uses a Butterfly [Spicebush Swallowtail [Papilio troilus] is a known pollinator], After leaving the inflorescence [flower] can have one or both pollinarium attached to it's eye[s]. Having dual openings to the spur [nectary] in Platanthera species that places the pollinarium on the tongue of the pollinator is common and is another ingenious way of insuring pollination in orchids. It should also be noted that Platanthera lacera emits its sweet odor only at night to draw in its pollinating moth. Schuylkill County, Pa. 8-1-22