About the aphid
Corn leaf aphid, Rhopalosiphum maidis, is a globally distributed pest of grains including maize, sugarcane, millet, sorgum, and barley (seen here). Rhopalosiphum maidis will stay on these grain hosts all year in many warmer locations, but in places with colder winters may either move to woody hosts in the genus Prunus or, more typically, simply reinvade every spring from warmer locations. Females typically give birth to more females year-round and males are rarely recorded, making it what entomologists call ‘anholocyclic’ (without a complete lifecycle) in most locations. These aphids are an interesting almost blue-green color, with darker areas around the head, thorax, legs and cornicles that become more pronounced in adults. Besides feeding damage, R. maidis can transmit several plant viruses and also produce substantial buildups of sticky honeydew which may can foster the growth of surface fungi.
About the photos
I ended up getting quite a few shots of R. maidis that I am satisfied with, and got good representation of winged and wingless adults as well as many stages of nymphs. I am finding that, for the most part, I have more luck getting interesting shots with aphids on stems and narrow leaves of grasses than broad leaves. A narrow leaf or stem allows me to shoot the aphids from a greater variety of angles. When aphids are along a leaf margin, I can even get some nice side-profile shots that make mouthparts, eyes, and leg attachments easier to see. The parallel veins of grasses like barley can also add a nice texture.
In several of the shots, cast skins (exuviae) of molting aphids are visible. These white or grey exuviae are sometimes confused with either live or dead whole aphids, but are simply an indicator that aphids are or were recently present. Most if not all aphids (I cannot remember if there are exceptions right now) molt four times between birth and adulthood, so often there are as many or more of these cast skins on infested plants as there are live aphids.
About the aphid
Next up is Sitobion avenae, also known as English Grain Aphid. The lead picture of a single alate (winged aphid) is one of my favorites I have taken so far and made an appearance in my introductory post. S. avenae is a widely distributed aphid that primarily feeds on grasses. It is notable for being a pest on wheat and other cereals around the world. We raise this species and a number of other grain aphids on barley. While all the individuals in our colonies and pictured here are yellowish green, they can also be found in a reddish brown color. S. avenae is a medium-large sized aphid and fairly easy to spot on leaves and stems.
About the photos
A number of these photos have a dark or black background. This is simply due to the flash coming from overhead, illuminating the aphids much more than the background behind them. There is no special backdrop behind them. If the flash was pointing straight at the aphids from the same direction that the camera sees them, you would see rows of large growth chambers in the basement room where these were taken. The lights were on in the room, but are just much lower intensity than the flash. Since barley leaves and stems are so narrow, it is easier to get a lower angled “eye-level” with these aphids than others on broader leaves.
I tried holding a piece of white paper behind the aphids but was not satisfied with how it turned out grey like this photo of an alate about to take flight.
It is still an interesting action shot, but I think the grey color takes away from it. To get a true white background I think I would have to have more light pointed straight at the paper, or have the paper much closer to the subject. Also a green or blue background could be interesting. Maybe something to try in the future.
Shorter post this time, but more photos. I also took some pretty nice photos of a couple green lacewings (Neuroptera: Chrysopidae) yesterday, so may have to take a detour for the next post before getting back to more aphids.
MC Kaiser Blog
Photographs of aphids by an enthusiastic amateur.
Images free for educational use with attribution.
Please contact me for any other uses, or visit my portfolios at Shutterstock and Dreamstime
First post and introduction here
If you are trying to identify live aphids from pictures, I highly recommend the website InfluentialPoints.com
For ID keys and a quite comprehensive catalog of aphids and their host plants see Aphids on the World's Plants
There is always the chance of one of our colonies getting contaminated and me posting a misidentified aphid. These images therefore should not be used to make formal identifications.
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