Amorpha juglandis
In 3 days ~20% in a week ~40%
Amorpha juglandis, the walnut sphinx, is the only species in the monotypic moth genus Amorpha, which is in the family Sphingidae, erected by Jacob Hübner in 1809. The species was first described by James Edward Smith in 1797.
It is native to North America, where it is distributed from the Atlantic Ocean to the Rocky Mountains in Canada and the United States. The wingspan is 45–75 mm. The adult moth is nocturnal, active mainly during the early hours of the night.
The caterpillar feeds on alder (Alnus), hickory (Carya), hazelnut (Corylus), beech (Fagus), walnut (Juglans), and hop-hornbeam (Ostrya) species. When attacked by a bird, the caterpillar produces a high-pitched whistle by expelling air from pairs of spiracles in its abdomen. This whistle is similar to the alarm signal produced by various bird species. One group of researchers in Montana hypothesized that this is a form of mimicry that functions as an antipredator adaptation to startle the bird, causing them to potentially reject the caterpillar.
Bura, V. L.; Rohwer, V. G.; Martin, P. R.; Yack, J. E. (2010). "Whistling in caterpillars (Amorpha... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 2 | Cumbres de Monterrey National Park | 🇲🇽 Mexico | |
| 3 | Shenandoah National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Austin | 🇺🇸 United States | |
| 2 | Dallas | 🇺🇸 United States | |
| 3 | San Antonio | 🇺🇸 United States | |
| 4 | Monterrey | 🇲🇽 México | |
| 5 | Houston | 🇺🇸 United States | |
| 6 | Washington | 🇺🇸 United States | |
| 7 | Toronto | 🇨🇦 Canada | |
| 8 | New York City | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Walnut Sphinx sighting in San Antonio on a given day, based on 101 verified sightings from GBIF citizen-science data. It is the 94th most-seen of the 697 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
March to November
In those months about 10% of wildlife watchers report a Walnut Sphinx in San Antonio on a given day, against under 5% in December to February, the lowest months.
Between midnight and 3 am
Across all the parks we cover, that three-hour window holds the most Walnut Sphinx sightings with a recorded time, and about 6 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
Among the best
Of the 8 cities where we can rate Walnut Sphinx sightings, San Antonio ranks 3rd at about 10%, level with the leaders once rounded. The best odds are in Austin (United States, about 10%) and Dallas (United States, about 10%).
Same family: Sphingidae
The closest relatives of the Walnut Sphinx that you can see in San Antonio (family Sphingidae, Sphinx Moths) are White-Lined Sphinx (about 10%), Vine Sphinx (about 10%) and Carolina Sphinx (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Walnut Sphinx is recorded against all the insects logged in San Antonio (101 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.
