{"id":53,"date":"2015-04-03T01:52:18","date_gmt":"2015-04-03T01:52:18","guid":{"rendered":"https:\/\/aphidtrek.org\/?page_id=53"},"modified":"2025-10-13T17:26:04","modified_gmt":"2025-10-13T17:26:04","slug":"aphis","status":"publish","type":"page","link":"https:\/\/aphidtrek.org\/?page_id=53","title":{"rendered":"Aphis"},"content":{"rendered":"\n

Aphis<\/em> Linnaeus<\/strong><\/p>\n\n\n\n

This page updated: December 2024.<\/p>\n\n\n\n

This is the most speciose genus of aphids, with over 500.  That is about 10% of all aphid species.  It seems to me to speciate readily in association with host plant species or genera.  My feeling is that there are many species yet to be discovered and\/or described, but also that there are many synonymies yet to be discovered and documented.  Some of the latter will undoubtedly be host-alternation biologies that have yet to be elucidated.  I have two probably undescribed species of black Aphis<\/em> from interior parts of Oregon and neighboring states on Veratrum<\/em> (Liliaceae) and Hackelia<\/em> (Boraginaceae). I also have a very cool species that feeds on Potentilla gracilis<\/em> but looks a lot like members of Aphis (Zyxaphis)<\/em>.<\/p>\n\n\n

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\"Aphis<\/a>
Aphis sp., probably undescribed, from Potentilla gracilis in Oregon.<\/figcaption><\/figure>\n<\/div>\n\n
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A very unusual Aphis on Mertensia paniculata in southwestern Idaho.<\/figcaption><\/figure>\n<\/div>\n\n\n

I also have a beautiful species from several Umbelliferae (including Sphenosciadium capitellatum, Perideridia<\/em>, and Lomatium<\/em>) in southern Oregon, which for years evaded good photos due to its habit of getting up and running as soon as its plant is disturbed; a good photo was finally achieved in 2020. Interestingly, what appears to be the same species lives on the large lower leaves of Helianthus<\/em> in western Colorado. Although this species keys out to A. asclepiadis<\/em> (see below for information and photos), it is distinctive in terms of color in life, behavior, and a few taxonomic features when cleared and mounted on slides. So, the questions become, Are all the samples I’d previously identified as A. asclepiadis<\/em> correctly identified, and this is a separate species? Or, is this actually A. asclepiadis<\/em> and all my other samples are something else? Or, are both part of a single extremely variable species? In 2021-22 I had eggs of this species overwintering in a mesh bag on Cornus<\/em> in our yard. In spring this bag was empty, but an inflorescence above it had this aphid on it. Given the apparent habit of new-born fundatrices of many aphid species to wander their plants for the best feeding sites, it’s likely that this population on the inflorescence arose from my mesh bag. Anyhow, the aphids were obviously of this color form and were morphologically recognizable from what I typically call A. asclepiadis<\/em>.<\/p>\n\n\n\n

Here in early 2024 I was tempted to pontificate about the lumping and splitting that are going on simultaneously in aphid classification. But, after sitting here with fingers poised over keyboard for an hour, I decided to hold off and attempt a separate essay on the subject later. I’m sure there will be thousands of you checking back here in anticipation!<\/p>\n\n\n

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An Aphis species that feeds on Umbelliferae in the mountains of Oregon and California. This one was on a desert-inhabiting Lomatium in the spring time.<\/figcaption><\/figure>\n<\/div>\n\n
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The mysterious Aphis that feeds on lower leaves of Helianthus in western Colorado.<\/figcaption><\/figure>\n<\/div>\n\n
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The Aphis on Helianthus in our gardens September 2025. These are closer to normal coloration for what is called Aphis asclepiadis\/carduella\/helianthi in the mountains of western North America.<\/figcaption><\/figure>\n<\/div>\n\n\n
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Species covered below (click on the name to jump to that species):<\/h2>\n\n\n\n