Pemphigus spyrothecae
In 3 days ~10% in a week ~20%
Pemphigus spyrothecae, or the poplar spiral gall aphid, is a social insect which exhibits apparent altruistic behaviors. The aphids form galls and act as colony defenders, at times sacrificing their own lives to do so. It has been shown that colony defense is more likely in habitats that are difficult to obtain and can hold a large number of individuals. These gall locations are crucial because plants have a short window in which a gall can be produced. Thus, it is important for there to be a defense system that enables the aphids to retain their galls. The need for defense arises when the gall is opened up to allow winged aphid migrants to leave and to release any waste. The process of repairing the holes can take up to 10 days; during this time, the gall is susceptible to intruding predators.
P. spyrothecae is green, red or yellow in color and smooth to the touch. The outer surface of this species develops as the edges of the petiole of Populus nigra thicken, flatten and twist. In parallel to the petiole's shape, a gall forms into a spiral shape similar to that of the inside of a snail's shell. The fundatrix, or parthenogenetic female aphid produced on the primary... Wikipedia →
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More parks will be added in future updates.
Rare
Under 5% of wildlife watchers report a Poplar Spiral Gall Aphid sighting in Seattle on a given day, based on 10 verified sightings from GBIF citizen-science data. It is the 275th most-seen of the 428 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.
September
In that month about 10% of wildlife watchers report a Poplar Spiral Gall Aphid in Seattle on a given day, against under 5% in October to August, the lowest months. That is one of Seattle's driest months, with about 60 mm of rain against 190 mm in November.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Poplar Spiral Gall Aphid sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
9th of 11
Of the 11 cities where we can rate Poplar Spiral Gall Aphid sightings, Seattle ranks 9th at under 5%. The best odds are in Kharkiv (Ukraine, about 10%), Liverpool (United Kingdom, about 10%) and Berlin (Germany, about 10%).
GBIF citizen-science records
It is estimated from how often the Poplar Spiral Gall Aphid is recorded against all the insects logged in Seattle (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.
