Few summer insects are as beloved as butterflies. The fluttering critters are celebrated for their dramatic metamorphosis and their decorated wings. But, how much do we know about the butterfly’s way of life? Two Ontario entomologists talk about butterfly basics, debunk common misconceptions and share some unsung facts about these flutter-bys.
1. What do butterflies eat, anyway?
In their adult stage, they eat a drastically different diet than they do as caterpillars. This as a result of their physical build.
“Butterflies have what’s called a proboscis, which is essentially like a straw stuck to their head,” says Jessica Linton, a terrestrial and wetland biologist based in Waterloo, Ont. After tasting a flower’s nectar with their feet, their proboscis uncoils, and they drink to their content. But as adults they can only drink fluids.
Caterpillars, on the other hand, use their mandibles—pincher-shaped mouthparts—to eat plant matter, such as leaves. This makes easy for them to eat and grow, which is vital in their caterpillar phase. In Ontario, Linton says, all caterpillars are vegetarians except for the harvester, who feeds on tiny green aphids.
2. Butterflies are pollinators, right?
Because they frequent flowering gardens with the keystone pollinators, bees, butterflies are commonly seen as pollinators too. This isn’t exactly true, at least not in Canada. They play a “minor role” in Canada, Linton says. “They do pollinate, but they’re not as important as pollinators as bees.”
Interestingly, they seek flowers for nectar, not pollen. “If there’s any pollination done by butterflies, it’s incidental,” says Antonia Guidotti, an entomology technician at the Royal Ontario Museum in Toronto. Flies and wasps are better pollinators, she adds.
3. How can I make my yard butterfly-friendly?
If you want your garden to attract these spectacular insects, you must also consider the needs of their complete life cycle. For butterflies, you want a variety of colourful flowers that bloom throughout the season, Linton says. They will feed in your garden as adults if you have nectar, but to keep them reproducing in your garden, “you have to provide the correct larval food plants for them.”
Butterflies and caterpillars have specific diets, Guidotti says. You can’t move caterpillars from plant to plant and assume they’ll eat anything. As a larva, the Black Swallowtail butterfly is called the parsley caterpillar. It feeds on parsley, dill, and fennel, for example. It won’t eat if you move it to a tomato plant.
4. What can butterflies tell us about where we live—and how can we help them?
For her Master’s, Linton investigated butterflies as indicators of changes in their environment. Linton likens their relationship with their habitat to a canary in a coal mine. Significant changes in their occupancy in an area or behaviour, usually indicated a larger problem in the environment.
The Monarch, the Mottled Duskywing and the West Virginia White are at-risk species in Ontario and human causes like habitat fragmentation are to blame. Three others—Karner Blue, Frosted Elfin, and Eastern Persius Duskywing—have disappeared from Canada altogether.
Perhaps it’s finally time to listen to our “canary” and protect the habitats of our nectar-loving neighbours. You can help scientists by sharing your butterfly sightings on citizen science apps such as iNaturalist.
Read more about how you can help butterflies survive.