Week 2:The Common Brown Butterfly (Heteronympha merope)
All 5 Families of Butterflies are represented in South Australia. The Skippers & Darts (Hesperiidae), the Gossamer-winged (Lycaenidae), the Whites & Yellows (Pieridae), the Swallowtails (Papilionidae), and the Brush-footed (Nymphalidae). Within the Brush-footed Family we find one of Greater Adelaide’s most numerous Butterflies, the Heteronympha merope, unsurprisingly named the Common Brown.
The adult Butterflies begin appearing in mid-spring. The sexes are strongly dimorphic. The males, orange/brown with black stripes, fly until February. These can be mistaken at times for the smaller Common Xenica (Geitoneura klugii) as they have similar patterns. The females, more orange/yellow with black patches and soft yellow spots, aestivate during the hot Summer. They emerge in early Autumn to begin egg development and laying. The peak laying occurs during March, however the females can still be found in April, although often with faded colours and tattered wings.
They can be found throughout the Greater Adelaide region and are common in the Adelaide Hills, although historically more so. The females can be found feeding on flowers from early Autumn and can occur in large numbers on roadsides feeding on the introduced Sweet Scabious (Sixalix atropurpurea) flowers. The are well camouflaged when resting, particularly when their wings are folded up, and are quite timid and will take to the air often before you can get within a few meters. The best chance of capturing a photo of these is to follow the movement of one that has taken flight, observe where it lands and sneak up on it. This may take a few attempts.
According to the IUCN Red List, the Common Brown’s conservation status is currently of least concern, however in the Greater Adelaide region due to habitat decline, particularly the native grasslands that the caterpillars feed on, its numbers are not what they used to be.
On iNaturalist the Common Brown is currently the most observed Butterfly in the Greater Adelaide region with 188 observations, 36 of which were recorded in April and all were female.
Evidence suggests that a warming climate is leading to earlier emergence of this species of Butterfly. Help to collect valuable data on presence and flight times by taking a photo and uploading it to iNaturalist during the City Nature Challenge.
It's very interesting to see how much these numbers have changed as iNaturalist has grown; there were 188 observations of this species in Greater Adelaide in 2020, but now that number has soared to over 1,300!