Lixus concavus
In 3 days ~10%
Lixus concavus, commonly called the rhubarb curculio, is a species of weevil. Rhubarb (Rheum species) is a host, together with dock, sunflower, and various species of thistle. L. concavus has a distinctive long snout and geniculate antennae with small clubs. The beetle is about half an inch in length, black, covered with yellow dust, and hibernates as an adult. Eggs are a yellow-white colour and oblong in shape; the legless larva is a grub, about 3/4 inch in length, with a brown head that usually bears an inverted, Y-shaped mark.
The adult rhubarb curculio overwinters in leaf litter or other similar sites and appears in mid-May. The adult makes feeding and egg punctures in the crowns, roots, and stalks; a jelly-like sap exudes from the wounds as glistening drops of gum, often with extraneous material trapped within. The eggs laid in rhubarb do not hatch, but are killed by the sap or crushed by the developing tissues.
Lixus concavus is able to complete its lifecycle in the stalks of curly dock, sunflowers, and thistles; eggs are laid singly in 1⁄8-inch-deep (3.2 mm) cavities, created by feeding activity, and hatch within a week to 10 days. One... Wikipedia →
| # | Park | Country | Daily sighting probability |
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More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
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| 1 | Chicago | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Rhubarb Weevil sighting in Chicago on a given day, based on 6 verified sightings from GBIF citizen-science data. It is the 814th most-seen of the 978 insects we can rate there. Over three days the chance rises to about 10%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Rhubarb Weevil in Chicago on a given day, so our monthly data shows no clear season.
Only Chicago, in our data
Chicago is the only city on Wallace's Line with enough records to rate Rhubarb Weevil sightings: under 5% of wildlife watchers there report one on a given day.
Same family: Curculionidae
The closest relatives of the Rhubarb Weevil that you can see in Chicago (family Curculionidae, True Weevils) are Black Vine Weevil (about 10%) and Green Immigrant Leaf Weevil (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Rhubarb Weevil is recorded against all the insects logged in Chicago (6 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.
