Antheraea yamamai
In 3 days ~10% in a week ~20%
Antheraea yamamai, the Japanese silk moth or Japanese oak silkmoth (Japanese: yamamayu(ga) (山繭(蛾)・ヤママユ(ガ)) or tensan (天蚕)) is a moth of the family Saturniidae. It is endemic to east Asia, but has been imported to Europe for tussar silk production and is now found in southeastern Europe, mainly in Austria, northeastern Italy, and the Balkans. It seems to be spreading north and a population has been reported near Deggendorf and Passau in Germany. The species was first described by Félix Édouard Guérin-Méneville in 1861. It has been hybridized artificially with Antheraea polyphemus of North America.
This moth has been cultivated in Japan for more than 1000 years. It produces a naturally white silk that is very strong and elastic, but does not dye well. It is now very rare and expensive. The wingspan is 110–150 millimetres (4.3–5.9 in). Adults are on wing from August to September in one generation depending on the location.
The larva mainly feed on Quercus species, but have also been reported on Fagus sylvatica, Castanea sativa, Carpinus, Rosa, and Crataegus. In order to look at the tensan silk genes in more detail a de novo genome and set of transcriptomes have been sequenced, producing a 700Mb reference with 15,481 genes. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Triglav National Park | 🇸🇮 Slovenia | |
| 2 | Plitvice Lakes National Park | 🇭🇷 Croatia | |
| 3 | Nikko National Park | 🇯🇵 Japan | |
| 4 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 5 | Fertő-Hanság National Park | 🇭🇺 Hungary |
Rare
Under 5% of wildlife watchers report a Japanese Silk Moth sighting in Tokyo on a given day, based on 14 verified sightings from GBIF citizen-science data. It is the 557th most-seen of the 1013 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 Japanese Silk Moth in Tokyo on a given day, against under 5% in October to August, the lowest months. That is one of Tokyo's wettest months, with about 210 mm of rain against 75 mm in February.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Japanese Silk Moth sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
3rd of 3
Of the 3 cities where we can rate Japanese Silk Moth sightings, Tokyo ranks 3rd at under 5%. The best odds are in Osaka (Japan, about 10%) and Seoul (South Korea, under 5%).
GBIF citizen-science records
It is estimated from how often the Japanese Silk Moth is recorded against all the insects logged in Tokyo (14 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.
