Missouri Master Naturalists- Springfield Plateau Chapter

Wednesday, May 27, 2020

Black Bean Aphids

Black mass on goat's beard - Ben Caruthers
Ben Caruthers captured this dramatic scene while photographing goat's beard, Tragopogon dubius.
"I had tried to catch the flowers open for photos for a couple days, but they close when it is cloudy or when the sun is low in the sky. I just noticed the black on the stalks and noticed the ants crawling gently around the black areas. It was only when I took a macro photo that I was able to see what was happening."
A. fabae - from Wikipedia
Tonya identified the mound of bodies as black bean aphids, Aphis fabaeAccording to Aphidnet it is found in the temperate regions of the northern hemisphere and in cooler regions of South America, Africa, and the Middle East.  It also has one of the widest appetites and has been reported on almost 120 plant families.  It breeds profusely by live birth and the large numbers attract a large number of predators.  Like many aphids, they produce abundant honeydew. They are commonly farmed by ants which lap up the sweet secretions and protect the aphids from predators.


F. subsericea - Ben Caruthers
The ant is a black mound ant - Formica subsericea, identified for me by James Trager who has written about them in this Antwiki link.  They are known to be enslaved on occasion by several other Formica sp. of ants.  The condition is a form of parasitism called dulosis and in a few cases the slaver ant species is completely helpless without their slaves.



F. subsericea has been studied for its unusual ability to travel across water, at times walking on top and other times swimming by using their front legs for propulsion while steering with their hind legs.  (Gripshover)

Every native plant has a story.  You just have to be curious like Ben and look closer.