Tough, charming, rough around the edges. The comma is one of the few butterflies that is becoming more widespread, likely due to global warming.
Comma butterfly Habitat
Look for question mark butterflies throughout the eastern U.S. to the Rockies and into southern Canada. They are common in populated areas such as parks and backyards, as well as woodland clearings and streams.
Look for comma species from coast to coast. You may see eastern commas (Polygonia comma) and gray commas (Polygonia progne) in the eastern part of the country. In the west, you’ll see hoary commas (Polygonia gracilis) and satyr commas (Polygonia satyrus). They all look very similar and are instantly recognizable with their sharp wing angles, bright orange coloration on top, and drab underwings with comma markings.
What do comma butterflies look like?
Caterpillars: mainly brown and black with a large white mark along its back towards its rear end. It is also covered in many branched spines.
Adults: orange-brown butterfly with darker markings. It has an unusual wing shape with irregular edges and a distinctive white ‘comma’ shape on the underwing.
Size and Family
Family: Nymphalids
Size: Medium
Wing Span Range (male to female): 55-60mm
Conservation Status
Butterfly Conservation priority: Low
European status: Not threatened
Caterpillar Foodplants
The most widely used foodplant is Common Nettle (Urtica dioica). Other species used include Hop (Humulus lupulus), elms (Ulmus spp.), currants (Ribes spp.), and Willows (Salix spp).
The Comma is a fascinating butterfly. The scalloped edges and cryptic colouring of the wings conceal hibernating adults amongst dead leaves, while the larvae, flecked with brown and white markings, bear close resemblance to bird droppings.
The species has a flexible life cycle, which allows it to capitalize on favourable weather conditions. However, the most remarkable feature of the Comma has been its severe decline in the twentieth century and subsequent comeback. It is now widespread in southern Britain and its range is expanding northwards.
What do comma butterflies eat?
Caterpillars: stinging nettle is the preferred food, but adults will also lay eggs on species of willow, currant, elm and hops.
Adults: feed on nectar of wild flowers such as thistle and knapweed. They can also be seen feeding on ripe blackberry and fallen fruit such as plums in autumn.
Eggs: Eggs are green and the surface is sculptured with a series of vertical ridges.
Figure 3. Eggs of the eastern comma, Polygonia comma (Harris). Photograph by Donald Hall, University of Florida.
Larvae: Full grown larvae are approximately 1.2 inches in length (Minno et al. 2005). The head has short spines and a pair of branching spines on top. Body color is highly variable, from white to greenish-brown to black, and the branching spines (scoli) on the body are also variable from black to white with black tips (Opler and Krizek 1984, Scott 1984).
Figure 4. Larva of the eastern comma, Polygonia comma (Harris). (Perry County, Indiana.) Photograph by Donald Hall, University of Florida.
Pupae: Pupae are variable in color but always have prominent ventral gold or silver spots. The pupae are attached to a silk pad by the cremaster.
Figure 5. Ventral view of the pupa of the eastern comma, Polygonia comma (Harris), showing silvery patches . (Perry County, Indiana.) Photograph by Jerry Butler, University of Florida.
Introduction
Species in the genus Polygonia are referred to collectively as the anglewings. The eastern comma, Polygonia comma (Harris), is also known as the hop merchant and the comma anglewing (Miller 1992). It is a relatively small inconspicuous butterfly that is rather closely associated with moist woods where its preferred nettle hosts grow, but it sometimes strays into other areas. With its wings folded, it resembles a dead leaf and is highly cryptic.
Life Cycle and Biology
There are two generations per year, with the summer brood probably estivating for much of the summer as adults and the fall-winter brood overwintering as adults (Butterflies and Moths of North America 2017). Adults feed on fermenting fruit and tree sap but rarely on flower nectar (Scott 1986). Males perch in the sun on foliage or tree trunks to await females (Opler and Krizek 1984) and defend territories (Bitzer and Shaw 1983).
Eggs are laid singly or in stacks on the undersides of leaves or less commonly on twigs. Larvae rest on the undersides of leaves and make nests by silking together the two sides. They hide in the nests during the daytime and feed at night.
How do comma butterflies breed?
Female comma butterflies mate with several males to fertilise their eggs. They are able to distinguish between males that have fed on high-quality and low-quality plants and will favour the former. The fertilised female lays her eggs on the leaves of stinging nettles and other larval food plants. The eggs hatch after around five days and the caterpillars will feed on the leaves before undergoing pupation.
Hibernation
The comma hibernates in woodland, usually in hollow trees or log piles. They leave their hibernation spot on warmer winter days and emerge completely in March.
Where do comma butterflies live?
By the mid-1800s the comma was confined to the Welsh Marches, perhaps because of a decline in hop-farming – hops being a favourite food of comma caterpillars. After adapting its preferences to nettles instead its range has expanded. The comma is now found in woodland clearings and gardens throughout England and Wales and has even edged into Scotland. This northward expansion may have been aided by the UK’s warming climate.
