Crawlies with Cri: Conifer sawfly

(Photo by Christy Solo for the Illinois Valley News)

Conifer sawfly (Genus Neodiprion)

This week’s crawly is in the same order as bees and wasps. While they may look a little waspy, they are their own unique critter. Our featured mister also happens to have ab fab antennae. Meet the conifer sawfly (Genus Neodiprion).
Let’s do a quick review: “What is a sawfly?”
While related to wasps and bees, they do not sting. The name “sawfly” comes from the females’ saw-like ovipositor which they use to cut slits into leaves or new shoots of their host plants. The females then lay their eggs into the snug spaces they’ve sawed.
Sawfly larvae look like caterpillars. They have more prolegs (working legs) and are always smooth and hairless. Sawfly larvae are more social and feed in large groups versus the solitary life most caterpillars live.
If a group of sawfly larvae feel threatened, they will all raise up the front half of their bodies in unison, hoping to scare away a potential predator. They lend credence to the “safety in numbers” theory.
Most sawfly larvae are brownish, green or yellowish-green and generally have black or dark brown heads. As they mature they develop spots or stripes on their bodies to give them better camouflage.
Sawfly larvae will chomp down needles and leaves on trees and plants, but the damage they cause is only cosmetic.
Adult sawflies feed on nectar and pollen; they are beneficial pollinators.
As their name implies, conifer sawflies depend on conifer trees to feed their young, but don’t panic. There are only 21 recorded sightings of conifer sawflies in Oregon, the majority of which are from Eugene northward.
Moreover, even if there were scads of sightings, conifer sawflies are rarely a critter who needs managing. They’ll have one or two “boom” years, but natural predators cut down on their population quickly.
There are 35 species of conifer sawflies in North America, and each species favors their own flavor of conifer. Several species go in for pine, but some also prefer fir. Some species prefer ponderosa pine but will settle for Douglas fir in a pinch.
The conifer sawflies’ lifecycle is about 12 months. However, some live from spring to spring, some from fall to fall.
Eggs laid in the fall overwinter snug in their needle sleeping bags. They’ll hatch in spring and munch on new growth needles. When they’re ready to morph into their papery cocoon form, they’ll dig into loose soil, or sometimes leaf litter. By the time they hatch into adults, they’ll be laying eggs that will also overwinter.
Meanwhile, another set of conifer sawflies will have overwintered in their papery cocoons and will hatch out in their adult form in late spring. Their eggs will hatch in summer and those larvae will eat more mature needles. They’ll morph into cocoon form in late fall and sleep the winter away waiting to get their wings in spring.
Adult conifer sawflies come in a range of colors: brick red, golden yellow and several species resemble our pictured fellow – black with a red abdomen. It can be tricky to tell the different species of conifer sawflies apart as individual species within the different colored groups can look nearly identical.
Only the males have the fantastic, feathered antennae. These are used to help the males sniff out females. Females have thin wasp-like antennae.