Common Water Penny vs Map Butterfly
Side-by-side species comparison
| Attribute | Common Water Penny | Map Butterfly |
|---|---|---|
| Scientific Name | Psephenus herricki | Araschnia levana |
| Order | Coleoptera | Lepidoptera |
| Family | Psephenidae | Nymphalidae |
| Size | 4-6 mm (adults); 6-10 mm (larvae) | 32-40 mm wingspan |
| Habitat | Rivers & Streams | Rivers & Streams |
| Diet | Omnivores | Omnivores |
| Regions | Eastern North America | Europe, temperate Asia |
| Conservation | Least Concern | Least Concern |
Common Water Penny
A small aquatic beetle whose larvae are flattened and round like a copper penny, clinging to rocks in fast streams. Adults are terrestrial and short-lived.
Did You Know?
Larvae are so flat they can cling to rocks in torrential currents that would wash away most other insects.
Map Butterfly
A small butterfly that produces two dramatically different seasonal forms within the same year. Spring adults are orange with black spots; summer adults are black with white bands.
Did You Know?
The seasonal colour change is triggered by day length during the larval stage, not temperature.