A beautiful female hoverfly (possibly Syrphus ribesii) spent the afternoon drinking nectar from the yellow florets of our Mexican Sunflowers. Also known as the Flower Fly and Syrphid Fly, hoverflies are members of the Syrphidae family of insects. As their name suggest, they hover over pollen- and nectar-rich flowers.
Helicoptering hoverfly coming in for a landing
Hoverflies are a wonderful addition to the organic, pesticide-free garden. Hoverfly larvae are aphid eating machines and they are also the second best pollinator, after bees. Female hoverflies lay their eggs in the midst of aphid colonies. When the eggs emerge, food for the larvae is readily available. A single hoverfly larvae can eat 400 to 500 aphids during the two-week period before pupating into an adult.
When flies look like bees – Hoverflies look similar to bees, with large bulbous eyes and black and yellow striped abdomens. Their color and buzzing sound mimics many species of bees and wasps, which helps ward off predators. Hoverflies are perfectly harmless and neither sting nor bite. You can tell the difference between a male and a female hoverfly by looking at the eyes. The eyes of the male are holoptic, which means they touch, whereas the eyes of the female are separated.
We have a colony of aphids on our Whorled Milkweed. I hope she stopped by to deposit her eggs there!
To attract hoverflies to your garden, plant plenty of nectar-rich flowers. One study showed some species prefer white and yellow flowers. Although the ray flowers of the Tithonia are orange, the disc florets at the center of the flower from where she was drinking nectar are yellow. Native plants that attract hoverflies include Lanceleaf Coreopsis, Common Yarrow, and Purple Coneflower. Hoverflies also love blossoms of herbs such as oregano, dill, parsley, coriander, and fennel.
Last fall, almost exactly to the day, through my office window I heard the sound of sweet voices on our front porch, well after dark, and wondered what our neighborhood dog walkers were doing out so late. It wasn’t dog walkers, but our neighbor Sharon and her son Treely, wondering what to do with what they thought was a Monarch caterpillar they had found in their garden. I sent them on their way with one of our terrariums and instructions on how to care for their little Black Swallowtail caterpillar.
Treely’s Black Swallowtail caterpillar turned into a chrysalis (in other words, pupated), spent the winter in the terrarium in a sheltered spot outdoors, and then emerged right on schedule this past spring. The Dowds returned the terrarium as it was needed later in the summer for our Cecropia Moth caterpillars.
Imagine how sweetly funny to get a call from my friend Michelle, wondering what to do with their newly discovered Monarch caterpillar. My first question to Michelle was did she find the caterpillar on her milkweed? No, she reported, it was found on carrot foliage. Michelle and her children, Meadow and Atticus, along with friend Sabine, stopped by this afternoon to learn about how to take care of their tiny little Black Swallowtail caterpillar and I sent them on their way with the ‘traveling terrarium.’
If you find a caterpillar in your garden, the first clue to identifying is to see on what food plant they are munching. Caterpillars that are actively feeding are usually only found on their larval host plant(s), the plant they have developed a distinctive coevolutionary relationship with over millennia. For example, female Monarch butterfly caterpillars deposit their eggs only on members of the milkweed family. Black Swallowtail caterpillars eat the foliage only from plants in the carrot family, which includes carrots, parsley, dill, fennel, parsnips, and Queen Anne’s lace. You may have noticed if ever weeding Queen Anne’s lace that the root looks identical in shape to a carrot, only it is white.
Chances are, you will never find a Black Swallowtail caterpillar on you milkweed plants and conversely, you will never find a Monarch caterpillar on your carrot plant (or parsley, dill, or fennel).
I am excited to hear from Michelle and the kids how their little caterpillar is developing over the next few weeks!
To celebrate Earth Day (Earth Week-Earth Month-Everyday is Earth Day!), I am beginning a new series on both my blog and on Good Morning Gloucester titled Habitat Gardening 101. The series is based on the lectures that I give to area conservation groups, libraries, garden clubs, and schools and is designed to provide information on the relationships between our native flora and fauna, and how to translate that information to your own garden. You will find in this series information on how to support and encourage to your garden a wide variety of wildlife, including songbirds, butterflies, bees, moths, skippers, hummingbirds, and small mammals, and the trees, wildflowers, shrubs, vines, and groundcovers that sustain these beautiful creatures.
This series could just as well be titled Beauty in Our Midst because there are so many gems to be found along our shoreline, meadows, fields, wetlands, dunes, woodlands, and roadsides. Although the series will cover a wide array of flora and wildlife, the first posts will be about several butterfly attracting trees and shrubs because they are currently in bloom. Coming Wednesday, the North American native Pussy Willow will be featured. For today, the following is one of my Top Ten Tips for Attracting Lepidoptera to Your Garden.
Habitat Gardening 101 Tip #1: Plant Caterpillar Food Plants
So you want to attract tons of butterflies to your garden and you plant lots of gorgeous, colorful nectar-rich plants—and that is wonderful. To your garden will come many beautiful, albeit transient, butterflies, along with an array of many different species of beneficial pollinators. However, if you want butterflies to colonize your garden, in other words, to experience the grand beauty of the creature through all its stages of life, from egg to caterpillar to chrysalis to adult, you must also plant caterpillar food plants.
Black Swallowtail Butterfly Egg on Fennel (the pinhead-sized golden yellow dot)
Each species of butterfly caterpillar will only eat from a family of plants it has coevolved a relationship with over millennia. We call this a caterpillar food plant, host plant, or larval food plant.
Perhaps you may recall that the Monarch Butterfly only deposits her eggs on milkweed plants. The Black Swallowtail Butterfly deposits her eggs on, and the caterpillars feast on, members of Umbelliferae (Apiaceae), or carrot family of plants, including carrots, parsley, fennel, dill, and Queen Anne’s Lace. Some caterpillars, like the stunning Eastern Tiger Swallowtail feed from several plant families, like those of Magnoliaceae and Rosaceae, which species include the Wild Black Cherry, the Tulip Tree, and the Sweet Bay Magnolia.
If you see a green, black and yellow striped and spotted caterpillar munching on your parsley plant, it is not a Monarch caterpillar; it is a Black Swallowtail caterpillar (I am often asked this question). Monarch caterpillars are striped yellow, black, and white, always. You will never find a Black Swallowtail caterpillar munching on milkweed; likewise you will never find a Monarch caterpillar eating your parsley and fennel.
Another question frequently asked is, if I invite caterpillars to my garden, will they devour all the foliage. The answer is, for the most part, no. The damage done is relatively minimal, the plant generally recovers quickly, and bear in mind too, that plants have evolved with many mechanisms to discourage their complete destruction. Remember, the plant was responsible for inviting the butterfly to its flower in the first place!
Note too, that if you invite butterflies to your garden to deposit their eggs, please don’t turn around and spray pesticides, which will kill all, indiscriminately. A habitat garden, by its very definition, is an organic garden, which means no herbicides, insecticides, pesticides, and chemical fertilizers.
Feel free to send any and all questions, suggestions for a topic, or curiosity, to the comment section under each post.
Cape Ann Milkweed Project Update: Because of the chilly spring weather, milkweed shoots are slow to emerge.
Last summer the Ciaramitaro girls stopped by our garden to see a newly emerged Monarch butterfly. After releasing the butterfly, Eloise wanted to learn more about the Monarchs, and butterflies in general. This year she remembered from their visit the previous year that the Monarch caterpillar food plant is milkweed. Eloise, who I am convinced is a budding naturalist and artist, is an avid gardener (just ask her about her vegetable patch!), so I promised her milkweed plants. We scouted out a sunny a corner of the family’s yard and, after mom Jill helped dig up the sod, we planted a petite butterfly garden, with Common Milkweed for the Monarchs, parsley and fennel for the Black Swallowtails, and marigolds to attract the nectaring insects. We’re looking forward to their first butterfly sightings!