This past weekend Pam was asked to water for a friend who was out of town. Since we live in an apartment I thought it might be an opportunity to find some common yard bugs that I don’t see very often, and though the diversity wasn’t large it was more than made up for by the fact that, because they are commonly found where people see them and wonder at their identity, they were quite easy to identify. In fact, while waiting for my photos to download from my camera, a very quick flip through the Miridae (plant bugs) section of ‘Pacific Northwest Insects’ (Peterson; 2018), a book about which I can never express too often my extreme gratitude for its usefulness, inclusiveness, and simple yet intuitive format, immediately showed me Phylus coryli.
This is a distinctive looking bug, and apparently there isn’t anything else that is particularly similar. And the identification clinching characteristic is that they are primarily found exactly where I found these, which is on domestic hazelnuts (filberts), where they provide the great service of munching on the aphids and other little creatures (nymphs eat up to 10 bugs a day) that are the bane of hazelnut growers. They don’t seem to have been purposefully introduced in North America, just (for a change) fortuitous little hitchhikers who came here when the plants were imported from Europe. When aphids are scarce they will sometimes hunt for them on nearby plants, and will even eat the hazelnut leaves if there is a complete dearth of prey, but neither adults nor nymphs attack the nuts themselves.
Description-Small (4.5-5.5mm), slender, shiny, brown to black bug with yellow to light green legs and antenna.
Similar species-There is really nothing else in our region that has this combination of size, light greenish yellow legs and antenna, and a shiny, dark body.
Habitat-Hazelnuts (Corylus spp., primarily C. avellana, the domestic filbert), although they may be found on nearby plants with better aphid hunting.
Range-Native to s Europe and w Asia; naturalized in North America; found in our region wherever there are hazelnuts.
Eats-Adults and nymphs feed on aphids and psyllids that feed on hazelnut and will also eat the leaves when prey is scarce, and do not feed on the nuts at any stage of development for either the nut or the bug.
Eaten by-I cannot find specific information on predators of this species, but I assume they are preyed upon by insectivores of all classes.
Adults active-June through August in our region
Life cycle-Eggs are laid at the base of the tree from June through August, but may not hatch until the following spring, or may overwinter in early instars- the literature I can access is not clear on this; apparently univoltine.
Etymology of names–Phylus may be from the Greek words for ‘small stature’, or from the Greek word for ‘a guard’, but I can’t find any corroboration for either of these ideas. The specific epithet coryli refers to the hazelnut, Corylus avellana, upon which it lives.