Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes

Calendar
Upcoming Events

Discussion of 2018 gathering

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Photos of insects and people from the 2014 gathering in Virginia, June 4-7.

Photos of insects and people from the 2013 gathering in Arizona, July 25-28

Photos of insects and people from the 2012 gathering in Alabama

Photos of insects and people from the 2011 gathering in Iowa

Photos from the 2010 Workshop in Grinnell, Iowa

Photos from the 2009 gathering in Washington

TaxonomyBrowseInfoImagesLinksBooksData
Photo#296497
aphid with yellow ball - Uroleucon eupatoricolens

aphid with yellow ball - Uroleucon eupatoricolens
lancaster County, Pennsylvania, USA
June 29, 2009
Can you please tell me about the yellow ball on the aphid? What is it and why does the aphid hold it extended as pictured?

Moved
Moved from Aphids. ID (Uroleucon eupatoricolens) based on host plant, which looks like Eupatorium maculatum. I suspect the defensive secretion is released in response to being harassed by a predator, as you suggested.

Cornicle secretion.
It's a defensive fluid that would gum the mouthparts of predators when they would try to eat it

 
wow
Very interesting! Is the fluid produced in response to an immediate threat from a predator? I notice none of the other aphids have it and I wonder why.

Comment viewing options
Select your preferred way to display the comments and click 'Save settings' to activate your changes.