This blog provides an informal forum for terrestrial invertebrate watchers to post recent sightings of interesting observations in the southern Vancouver Island region. Please send your sightings by email to Jeremy Tatum (tatumjb352@gmail.com). Be sure to include your name, phone number, the species name (common or scientific) of the invertebrate you saw, location, date, and number of individuals. If you have a photograph you are willing to share, please send it along. Click on the title above for an index of past sightings.The index is updated most days.

2024 December 18

2024 December 18

Jeremy Tatum writes:  I visited Goldstream Park today, to see if I could find some female winter moths and if I could tell the difference between the flightless females of Operophtera brumata and O. occidentalis.

   There were lots of adult males of both species.  Females were more difficult to find – they do not fly to lights, of course.

I found the insect below, and I could see immediately that it was different from female O. brumata, so I was quite excited, thinking that it must be O. occidentalis.  It wasn’t until I got home and saw it on the computer screen that I saw that it wasn’t a moth at all – it was a small beetle.  Scott Gilmore kindly identified it as Plectrura spinicauda.

 Plectrura spinicauda  (Col.: Cerambycidae)   Jeremy Tatum

 

  I did, however, manage to photograph a genuine female Operophtera, which I think is highly probably O. occidentalis (photograph below), If you compare it with a known female brumata (see Invert Alert for 2023 November 22), you’ll see that the wing-stubs of this moth are much smaller than those of brumata.
Wing-stub size may be a reliable way of distinguishing the two species – though more photographs of the female would help to substantiate this.

 

Believed to be Operophtera occidentalis  (Lep.: Geometridae)   Jeremy Tatum