While we were in Colorado, we saw these cool metallic-blue larvae.
You might think they are caterpillars, but they are not.
These are the larvae of a leaf beetle.
Sometimes it is easy to forget that beetles have a larval stage like the other insects with complete metamorphosis, because you don’t see beetle larvae or pupae as often as you might see caterpillars.
The larvae are probably from beetles in the genus Trirhabda. You can see photographs of the adults at BugGuide.
Someone asked me about sawflies recently, so I thought I’d tell you a little about these commonly overlooked insects.
(This photograph is from Wikimedia by Lilly M.)
The colorful larvae in the photograph will become sawflies. Don’t they look like caterpillars?
If you look closely at the rear part or abdomen, you will see that there are six or more pairs of prolegs, one on each segment (see butterfly science post for a description of prolegs). Caterpillars lack prolegs on some segments, and thus have five or less pairs.
The larvae often fall the the ground and pupate in the soil. They will emerge as adults that are flying insects with four wings and thick waists.
This is photograph of an adult of another species (from Wikimedia)
Sawflies are relatives of bees, wasps and ants. If you could imagine Hymenoptera family tree, then the sawflies would be at the trunk, with the bees, ants and wasps forming the branches.
The larvae feed on plants, often on conifers. The larvae of many species feed in large groups, and display collective alarm behaviors. In the photograph above the sawfly larvae are displaying their abdomens. In other species all the members of the group may rear up suddenly when they are threatened, startling any potential predators. You can see rearing sawflies in action in this short video from the University of Kentucky.
Pretty scary isn’t it? I know I wouldn’t want to eat one.
Have you ever seen a sawfly before? Are they common where you live?
Did anyone have any ideas what the little bee was doing in the photos from two weeks ago?
Bees sometimes gather a number of different materials from leaves, including water, resin or sap. Because the plant is infested with lace bugs, which produce honeydew like aphids, I suspect this bee was licking honeydew from the brittlebush leaf. It is likely an example of an insect often considered to be a pest supplying the needs of an insect considered to be beneficial. Isn’t nature wonderfully complex?
For more information, see Roberta Gibson Writes.
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