Pterotus obscuripennis
In 3 days ~10% in a week ~30%
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 Portland on a given day, based on 30 verified sightings from GBIF citizen-science data. It is the 170th most-seen of the 507 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
May–June and December
In those months about 10% of wildlife watchers report a Douglas Fir Glow-Worm in Portland on a given day, against under 5% in January–April and July–November, the lowest months.
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.
Yes
Of the 4 cities where we can rate Douglas Fir Glow-Worm sightings, Portland has the highest daily chance: under 5%. Next come Sacramento (United States, under 5%) and San Diego (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 Portland (30 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.
