Sawfly – Dolerus unicolor

Sawfly – Dolerus unicolor
Family Tenthredinidiae

Insects & Spiders | Bees & Wasps Index | Bees & Wasps Main | Stinging Hymenoptera
Live adult sawflies photographed in the wild at northern Illinois locations.
Sawfly - Dolerus unicolor
I found this lovely sawfly as she doodled around in a weedy / grassy field in early April, before most insects have even thought about getting out and about. This species lays its eggs in a slit they cut in grass stems. Sawfly larvae resemble caterpillars of more familiar butterflies and moths. Most of them are herbivorous, and many are important agricultural pests, being leaf miners and/or gall-forming. Many adult sawflies are predators of other insects, and they are quite fearsome indeed – I have seen them devour small beetles in a matter of a few minutes.

Most sawflies are very particular about thier host plants. This species favors grasses and sedges; I have never seen an adult feeding. I love the iridescent blue-green set against the bright orange of the thorax – I'm always happy to spot one of these rare harbingers of spring.

Sawfly - Dolerus unicolor

Sawflies get their name from the saw-like nature of their ovipositor. This female is using her saw to slit open blades of grass wherein she lays her eggs. It took me many attempts before I was able to capture this process.

It is virtually impossible to tell what is going on while these creatures are laying eggs, it's so quick, and the structures involved are so small.

Sawfly Ovipositor
Sawfly Ovipositor – Dolerus nitens


Order Hymenoptera: Bees, Wasps, & Ants

Hymenoptera (Latin for membrane wing) is a vast assemblage of insects second only to Coleoptera (beetles) in the number of described species. Hymenoptera number some 115,000 species – of which 18,000 live in North America. Hymenopterans inhabit a wide variety of habitats, and show an incredible diversity in size, behavior, structure and color.
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