Biorhiza pallida
In 3 days ~10% in a week ~30%
Biorhiza pallida, also known as the oak apple gall wasp, is a gall wasp species in the family Cynipidae. This species is a member of the tribe Cynipini: the oak gall wasp tribe. Cynipini is the tribe partially responsible for the formation of galls known as oak apples on oak trees. These are formed after the wasp lays eggs inside the leaf buds and the plant tissues swell as the larvae of the gall wasp develop inside. This wasp has a widespread distribution within Europe.
Biorhiza pallida has a complex life cycle involving an agamic female that reproduces by parthenogenesis without a male during the winter/spring, and a summer generation of adults where individuals are either male or female. These mate and produce fertilised eggs.
The wingless agamic wasp is between 4.8 and 6.3 millimetres (0.19 and 0.25 in) long. The head is golden brown with mid-brown eyes and orange ocelli (simple eyes). The long antennae have fifteen segments and are orangeish-brown. The thorax, legs and bulbous, glistening gaster (abdomen) are yellowish-brown.
Male and female wasps that develop in the summer generation are smaller with a length between 2 and 3.5 mm (0.08 and 0.14 in). The head... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 2 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 3 | Sierra de Guadarrama National Park | 🇪🇸 Spain | |
| 4 | Wadden Sea National Park | 🇩🇪 Germany |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | London | 🇬🇧 United Kingdom | |
| 2 | Birmingham | 🇬🇧 United Kingdom | |
| 3 | Liverpool | 🇬🇧 United Kingdom | |
| 4 | Manchester | 🇬🇧 United Kingdom | |
| 5 | Leeds | 🇬🇧 United Kingdom | |
| 6 | Berlin | 🇩🇪 Germany | |
| 7 | Prague | 🇨🇿 Czechia | |
| 8 | Stockholm | 🇸🇪 Sweden | |
| 9 | Essen | 🇩🇪 Germany | |
| 10 | Warsaw | 🇵🇱 Poland |
Rare
Under 5% of wildlife watchers report an Oak Apple Gall Wasp sighting in Wadden Sea National Park on a given day, based on 15 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 422nd most-seen of the 818 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.
March to May
In those months about 10% of wildlife watchers report an Oak Apple Gall Wasp in Wadden Sea National Park on a given day, against under 5% in June to February, the lowest months. Those are among Wadden Sea National Park's driest months, with about 45 mm of rain a month against 140 mm in November.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Oak Apple Gall Wasp sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
4th of 4
Of the 4 parks where we can rate Oak Apple Gall Wasp sightings, Wadden Sea National Park ranks 4th at under 5%. The best odds are in Snowdonia National Park (United Kingdom, about 10%), Bavarian Forest National Park (Germany, about 10%) and Sierra de Guadarrama National Park (Spain, about 10%).
Same family: Cynipidae
The closest relatives of the Oak Apple Gall Wasp that you can see in Wadden Sea National Park (family Cynipidae, Gall Wasps) are Mossy Rose Gall Wasp (about 10%), Cherry Gall Wasp (about 10%) and Oak Marble Gall Wasp (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Oak Apple Gall Wasp is recorded against all the insects logged in Wadden Sea National Park (15 verified sightings from 2019 to 2026), 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.
