Tuesday, April 3, 2018

Pollination of Aristolochia californica


This flower is not showy. It is sort of greenish. And the maroon parts seem to blend in with the brown parts of the plant. If you are not looking for the flowers, they are easy to miss. So it is not pollinated by bees or butterflies, which usually visit colorful flowers. It is pollinated by fungus gnats. You can see the dead or unconsciousness fungus gnats a the bottom of this flower which has been cut open. They get in through the "mouth" at the upper right. Probably attracted by some mushroomy smell. They fly to the anthers, at the upper left. This part of the flower is light and bright, and they must think that they can get out that way. When they get tired out, they fall to the bottom, where they can see the light through the mouth, and find their way out when they revive. At least that is what I surmise, from looking at the flower, and knowing insect behavior. 

I have read that the insects escape when the flower wilts. However, as you can see from the faded flower below, the shape doesn't change when it wilts. So I don't see how that would work.
You can also see the fruit beginning to develop in the photo above. See the striped portion above the brown flower? That is the fruit when it is still tiny. 

I have read that fungus gnats like moist cool habitats. Which would make sense, because that is where mushrooms grow. I have noticed that pipevine plants that grow in the sun have few fruits, even if they have lots of flowers. Since the fungus gnats don't like that environment, they don't visit much, the flowers don't get pollinated, and the fruits don't develop. 

Some people think that since Pipevine swallowtails visit this plant, that they pollinate it. No, they lay their eggs on it. 

This plant has relationships with at least three different insects. The fungus gnats that pollinate it. The butterflies that lay their eggs on it. And the wasps that eat the seeds. 

And this is a poisonous plant! 

I am sure other plants have interesting relationships with many insects. But I know about this one because of the butterfly. 

1 comment:

Gregor Dietrich said...

After pollination of the stigma, or if not so, when the flower ages, the anthers will open and set the pollen free. Soon after that the part of the flower, where the light shines through, beneath the anthers, gets darkened, so that it gets dark inside. Also the hairs in the entrance of the flower wilt, else there is no way out. So at last the gnats can find the way out.