I so rarely get to see my specimens of Twinleaf, Jeffersonia diphylla, all flowering at once, let alone be pollinated by one another to see the seedpods. Normally the pods don't grow bigger than a nickle and shrivel up with nonviable seed inside. Today though I came across a fairly large seedpod. I reached down to see if it was soft enough to harvest and the darn thing broke right off the stem on me. Worst of all, the seeds weren't ready yet.... Waste not, want not.
The ants here are Aphaenogaster rudis, which is actually a complex of several species. DNA analysis to count the number of chromosomes is required for a true species ID but overall they're the same. The species names are more or less scientific codes instead of Latin names, so the blanket term A. rudis works fine. They're all commonly found in woodlands across North America, they all nesting in soil and sometimes rotten wood in contact to the soil. They all form colonies with populations ranging from 2,000 - 12,000 ants. Nests are small and move around on occasion, making them ideal seed dispersers, along with their size.
The ants find nourishment everywhere they can, even among the seedpod itself. If the ants didn't come along to clean out the seeds, rodents, birds, and wasps would have. Rodents and birds love eating the seeds. Wasps go for the elaiosome just like the ants, but are unlikely candidates for seed dispersal. They may drop them on the surface for birds and rodents to find, or bury them too deep within the earth, or the seed could end up within the dead branch of a tree.
One plant that was right on time was the Woodland Poppy, Stylophorum diphyllum. The same idea of seed dispersal applies, however I can't get it out of my head how much the elaiosome to this plant resembles ant brood. It just looks like clusters of eggs and larva, which ants are more than happy to eat, especially if it doesn't belong to them.
As a disclaimer I will admit all of these photos were staged to a point. You'll notice I just opened the seedpods and spilled them on a stepping stone where an Aphaenogaster rudis colony happens to nest. I just don't have the time to wait for this to happen naturally in my yard, but trust me it does. There are plenty of Woodland Poppy plants with open seedpods on them right now that have spilled their seeds in the garden. I typically find Tapinoma sessile and Crematogaster cerasi stealing the elaiosome from the seeds where they fell and don't disperse them. The occasional Aphaenogaster forager does find a few though and bring them back to the colony. Since they've been self seeding in my yard for the past three years now I've been finding Woodland Poppies coming up in places where ant colonies tend to nest, and or have been dragged away from the parent plant a short ways at least. Sometimes the ant carrying the seed home gives up or gets disturbed by a spider or something.
Turkey Corn, Dicentra eximia, will likely be the next plant who's seeds do this to ripen in my garden... sadly I missed my chance with Hepatica this year, but they seem okay about germinating where they fall anyhow. So though a plant uses this strategy to disperse its seeds, it's not always required for success, simply a way to give them a leg up.