Giant Willow Aphids are large (as aphids go), grey aphids with a dorsal tubercle which look somewhat like shark fin.
|Giant Willow Aphid - Tuberolchnus salignus|
Here is a photo of the aphid colony in the beginning of December.
Notice a few of them have wings.
|Colony of Giant Willow Aphids - Tuberolchnus salignus|
I went out one frosty morning to get a close-up picture showing frost crystals on the willow branch opposite the aphids.
|Frosty willow aphids|
Even if these remaining ones are dead, the aphid's cold hardiness is on display, because wherever the others went, it's just as cold there...just not as exposed to the wind, rain, and rapid temperature fluctuations.
When I first noticed the aphids feeding on our willow, the colony was quite small... see the picture below. These aphids are reported to only reproduce parthenogenetically - that is the female gives birth to a genetically identical daughter aphid through asexual reproduction. That means the aphids in large colony I photographed Dec 1st are all clones...genetically identical subdivisions.
Notice the aphids were being tended by many ants which were furiously defending their honeydew supply against an onslaught of intruding mosquitoes and other insects. I counted about a dozen diptera in this photo. There is also a small parasitic wasp in the right side of the picture approaching on a branch.
honeydew that it exceeded what the ants were "milking". The aphids jettisoned this excess honeydew, as evidenced by the wet spot on the ground (next picture) below the colony. The ants were there feasting at this honeydew puddle as well.
Winter's cold has quieted down all that flurry of activity.
Compare the next few pictures that show the aphid colony slowly dissipating in preparation for the dead of winter.
On (left picture) Dec. 1st, the colony was about at its peak. On Dec 18 (right picture) there were noticeably less aphids
By mid-January there were only a few stragglers (perhaps dead ones) left hanging around on the willow
Then...the show will go on!