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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

‘Twas the week before Christmas: Giant bark aphids, Longistigma caryae, and giant willow aphids, Tuberolachnus salignus


Some adult giant bark aphids have wings and others do not. These are the largest aphids in North America.


 ‘Twas the week before Christmas and what did I see,                                      Giant bark aphids on a leafless beech tree.

Aphids are not known for their very large size,                                                  But these babes on beech trees win the “big-aphid” prize.

These serious sap-suckers spent several past weeks                                        Sipping plant sap from branches through very long beaks.

Aphid moms suck sweet phloem by night and by day,                                      And transform it to nymphs - born alive, by the way.


In this colony of giant willow aphids, the large female on the upper left portion of the branch is giving birth to a daughter.


These strange spawning efforts are quite something to see,        Bug geeks call this birth-trick viviparity.

In the waning of fall, cold winds start to blow                                  And these gals change their plan. They just seem to know.

No more birthing youngsters on twigs in the cold,                         They lay eggs on branches, many thousand all told.


Braving icy winds and the season’s first snow, giant willow aphids try to squeeze out one more generation before Old Man Winter puts them to rest.


Tiny black eggs seem to be a perfect life stage                                To brave wicked winter when vicious storms rage.

And if aphids can hope, their fondest hope must be                      That no predators find these eggs on the tree.

Fear not giant aphids, be glad and be happy                                  In spring eggs will hatch when trees get all sappy.


Eggs of the giant bark aphid are the overwintering stage. They line small branches by the thousands and change from amber to black as they age.

       Happy Holidays from Bug of the Week!


Bug of the Week extends apologies to Clement Clark Moore. Like woolly alder aphids we met a few weeks ago, these aphids also reproduce parthenogenetically, that is, without males. To learn more about the magnificent giant aphids on beech and willows, please visit the following websites:

To witness aphid viviparity, please click on this link: