Jalmenus evagoras
In 3 days ~10% in a week ~30%
Jalmenus evagoras, the imperial hairstreak, imperial blue, or common imperial blue, is a small, metallic blue butterfly of the family Lycaenidae. It is commonly found in eastern coastal regions of Australia. This species is notable for its unique mutualism with ants of the genus Iridomyrmex. The ants provide protection for juveniles and cues for adult mating behavior. They are compensated with food secreted from J. evagoras larvae. The ants greatly enhance the survival and reproductive success of the butterflies. J. evagoras lives and feeds on Acacia plants, so butterfly populations are localized to areas with preferred species of both host plants and ants.
The wings of Jalmenus evagoras are metallic blue outlined with black. The hindwings have tails and orange spots towards the bottom. On the ventral side, wings are buff-coloured with black streaks and orange hindwing spots similar to the dorsal side. The butterfly has a maximum wingspan of 4 cm.
Little to no sexual dimorphism is observed between male and female adult butterflies. In the pupal stage, females can be up to 60% larger than males. Jalmenus evagoras lives along the east coast of Australia in... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Blue Mountains National Park | 🇦🇺 Australia | |
| 2 | Royal National Park | 🇦🇺 Australia |
Rare
Under 5% of wildlife watchers report a Common Imperial Blue sighting in Sydney on a given day, based on 42 verified sightings from GBIF citizen-science data. It is the 222nd most-seen of the 742 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.
February to April
In those months about 10% of wildlife watchers report a Common Imperial Blue in Sydney on a given day, against under 5% in May to January, the lowest months. Those are among Sydney's wettest months, with about 100 mm of rain a month against 45 mm in September.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most Common Imperial Blue sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
3rd of 3
Of the 3 cities where we can rate Common Imperial Blue sightings, Sydney ranks 3rd at under 5%. The best odds are in Brisbane (Australia, about 10%) and Melbourne (Australia, about 10%).
Same family: Lycaenidae
The closest relatives of the Common Imperial Blue that you can see in Sydney (family Lycaenidae, Gossamer-winged Butterflies) are Lesser Grass Blue (about 10%), Zizina labradus (about 10%) and Zebra Blue (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Common Imperial Blue is recorded against all the insects logged in Sydney (42 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.
