Friday, August 2, 2013
Aphids Making Gallons of Honeydew
It seems very pastoral in theory, but is the most chaotic and busy place around.
With these aphids the ants don't seem to get the reward directly from the aphids at all.
But look at all the aphids under the 6 feet and legs of the ant. And this is as big as they get, although there are many very little ones.
I measured the biggest aphids here at just under one millimeter.
The whole leaf had over 1,000, and there were 30 leaves on the plant, which means over 30,000 aphids on each plant. I counted 22 plants in this group, so over 660,000 aphids in this colony. Wow!
Their drops of honeydew are tiny, but if they added up to just one water droplet in volumn in a week per aphid, that would be 660,000 drops of honeydew per week. At 27 drops per teaspoon, that is over 7 gallons a week for this colony!
Here you can see one little droplet just released by this litle gal. I have turned the picture upside down so it is easier to see, so this droplet would actually be falling up to the leaf below it, onto the topside of the leaf.
With thousands of droplets falling onto the top surface of the leaf below you can imagine what a sweet, sticky, treasure trove the top of each leaf becomes.
Here you can see each tiny white spot is a droplet. The ants get fat eating these, which they can take back to the nest to feed baby ants with.
The ants also have to spend a great amount of time chasing away other critters who are interested in this enormous food source. They are not very successful.
But other insects come to feast as well. There are at least 8 flies that I can count on each plant at any one time. Lots of them flying all around.
Many are this red eyed species that is house fly size. Its sponge/mop like mouth is picking up the honeydew, but while it eats even more honeydew rains down from the bottom of the leaf above, covering the fly with little specks of sweet dew.
The aphids are growing on the leaf up above and shedding their skins as they grow. The shed skins fall as well. One can be seen under the fly here. It is white.
After a few weeks of this there is mouldy honeydew, fly droppings, shed skins, and anything the wind blows onto the sticky surface. It is a mess!
The entire top of the leaf is covered with this coating of sticky food.
Aphids can be seen on the underside of the leaf to the left. They are dropping more honeydew to the top of the leaf below.
With over half a million aphids and other food animals present, the predators show up. Several Ladybugs were hunting and eating aphids while I was photographing yesterday. The Ladybugs are too big for the ants, but there are so many aphids, they have little impact on their numbers.
This little milkweed patch is an extremely busy ecosystem. Nothing can compare to it nearby for the number of insects constantly entering and leaving, not to mention the over half million that live on it every day.