What is this?
Location: Anchorage, Alaska
September 4, 2011 7:31 pm
I saw these bugs eating an alder bush in my yard up here in Anchorage Alaska. I am wondering what they are and if I need to do anything about them. They are all over the alder bush.
We noticed that when they are touched the white spots on them pop out. I can’t find anything about them online.
These are Leaf Beetle Larvae, and we believe we found a good match on BugGuide that is identified as Chrysomela aeneicollis, and the photo is from Alaska. We would also admit that we are not certain of the species, since larvae are often difficult to identify with certainty, but we are relatively confident that we have the genus Chrysomela correct. Here is another similar looking unidentified larva from the genus Chrysomela, also from BugGuide. If you read the comments on this posting on BugGuide, you will see that the larvae are capable of emitting drops of odorous liquid from the white tubercles, which supports what you have written. Our one reservation is that from what we have read, beetles in the genus Chrysomela feed upon willow and poplar, and we haven’t found any indication that they feed upon Alder.