Pterotus obscuripennis
In 3 days ~10% in a week ~20%
Pterotus obscuripennis, commonly known as the Douglas fir glowworm, is a species of firefly in the beetle family Lampyridae. It is found along the western coast of North America, from Washington to California. Adult males are smaller (9.5-12 mm), alate, capable of flight, have an elaborate antenna morphology, and are totally non-luminous. Adult females are larger (~25-35 mm), fully larviform and flightless. They are cream to light golden brown in color and luminous with photo organs on the seventh and eighth abdominal segment. Larvae are largely black in color, with cream to white coloration in the spaces between the body segments, and are luminous and predatory on slugs.
The principle foods of the larvae is slugs and/or snails. A large part of the digestive process for larva is pre-oral: mandibles containing hollow centers are used to inject a brown fluid that is slightly alkaline, contains proteases, and observationally, likely contains a neurotoxin. When bitten, a slug writhes, secretes mucous, and tries to flee. The larva will bite the slug multiple times, causing the same response. Around 10 minutes after the first bite, the prey will become immobilized... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Portland | 🇺🇸 United States | |
| 2 | Sacramento | 🇺🇸 United States | |
| 3 | San Diego | 🇺🇸 United States | |
| 4 | Los Angeles | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Douglas Fir Glow-Worm sighting in San Diego on a given day, based on 10 verified sightings from GBIF citizen-science data. It is the 463rd most-seen of the 693 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Douglas Fir Glow-Worm in San Diego on a given day, so our monthly data shows no clear season.
Between 9 pm and midnight
Across all the parks we cover, that three-hour window holds the most Douglas Fir Glow-Worm sightings with a recorded time, and nearly all of them come between 6 pm and 6 am: it is mostly seen at night.
Among the best
Of the 4 cities where we can rate Douglas Fir Glow-Worm sightings, San Diego ranks 3rd at under 5%, level with the leaders once rounded. The best odds are in Portland (United States, under 5%) and Sacramento (United States, under 5%).
GBIF citizen-science records
It is estimated from how often the Douglas Fir Glow-Worm is recorded against all the insects logged in San Diego (10 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
