Crawlies with Cri: Longhorn Beetle

Molorchus longicollis longhorn

This week’s crawly put the “long” in “longhorn beetle.” Meet the Molorchus longicollis longhorn, a small but special bitty-bit of a beetle.
How small is he? How do we know he’s a he?
Our pictured Mr. is one-quarter of an inch in length. We know he’s a he because his antennae (AKA long horns) are over one-quarter of an inch in length; longer than the beetle himself. Female molorchus also have long antennae, but not quite as long. Female molorchus’ antennae are three-quarters the length of their bodies.
Mr. molorchus’ good looks and ab fab antennae alone are enough to make him special but wait – there’s more.
There is no shortage of longhorn beetles (Family Cerambycidae) in North America. There are about 1000 species within 300 genera.
Even within this enormous family, molorchus stand out in their scarcity. Their Tribe Molorchini only has one genus, and that genus only has three species.
By comparison, Tribe Lepturini has 34 genera with 112 species.
Not only is molorchus part of a tiny tribe, but they only live on the West Coast from Southern California up to Vancouver British Columbia. There are only 34 recorded sightings of molorchus on iNaturalist, and yet these bitty beauties live right here in our very own backyards.
Adults feed on nectar and pollen and favor tiny flowers, so they’ll pollinate blossoms bigger pollinators can’t effectively squeeze into.
Molorchus larvae do dine on wood, but so little is known about them we don’t know if they prefer live or dead wood. We do know that the larvae of molorchus’ cousin M. bimaculatus – which live in the Eastern US – chow down on dead wood. They specifically like dead branches on hardwoods, so it’s likely as not molorchus kiddos dine on dead wood too.
What we know for certain is that with only 34 recorded sightings, there simply aren’t enough of them in existence to cause noticeable damage. The small number of sightings isn’t due to molorchus’ small size; there are 807 sightings of that same cousin, bimaculatus, who are equally as tiny.
If you take a quick look at our pictured molorchus, you might notice another feature that makes them unique. They have shortened elytra (hardened wing covers).
The majority of North America’s 25,000 beetle species have long elytra that completely cover their wings. Molorchus really like to do things their own way!
Many species of rove beetles (Family Staphylinidae) have shortened elytra, but they also have wings which fold like origami up under those elytra, so the wings are fully protected. Molorchus just let their wings hang out in the open.
Our pictured Mr. may regret that as it looks like one of his wings is torn, the price you pay for being a true fashion original. Still, he was nonplussed by whatever caused him damage as he sat and groomed his face nonchalantly while I took his photo.
With such a small population, we may never know all the secrets Mr. molorchus could tell us, so we’ll just consider ourselves lucky he brings his pollinating powers and flashy sense of style to our area.