Pollinator of the Month: Margined Calligrapher

By Amy Yarger, Butterfly Pavilion Horticulture Director 

When it comes to pollinators, I try very hard not to have favorites. Every pollinator contributes to our quality of life, supporting the reproduction of our food plants, as well as the plants in our natural areas. However, I have a special place in my heart for certain pollinators who are ignored or even disdained, all the while quietly working their buggy magic. This month’s pollinator, the margined calligrapher (Toxomerus marginatus) is a fly (strike one in the pollinator popularity contest), tiny (strike two), and common (strike three), but it is such a beneficial visitor, I hope we can learn to appreciate its beauty and usefulness.  Margined calligraphers are a member of the hover fly family, or Syrphidae. Another vernacular name for members of this family is “flower flies”, because these flies uniformly visit blooming plants for nectar and pollen. But the secret benefit of many hover flies is their larval predilection for catching and eating pests such as aphids and thrips in your garden. If you attract margined calligraphers and their cousins, you are in effect getting a two-for-one deal: pollination and pest control.  Because they are so small, about 5 mm in length, it may be easy to miss these garden helpers, but they reward a closer look. Margined calligraphers, like many of their hover fly cousins, mimic bees and wasps with their bold warning patterns. In this case, these flies are gold and black, with a delicate yellow line etched around their abdomens. Sometimes, they can even make a low buzzing sound to complete the deception. However, you can easily tell the difference by looking at the single pair of flight wings, large eyes, and stubby antennae.  If you look still closer, you can even determine whether you are looking at a male or female calligrapher fly. Males have rounded abdomens and eyes that touch in the center, while the abdomen of females comes to a sharp point (not a stinger!). The colors of the pattern on each fly depend on the temperature during pupation – the hotter it is the more golden, the colder it is the blacker. And as you look closer at these flies, they sometimes return the favor, hovering right in front of your face, regarding you with their big fly eyes. Adults forage from June through October, but during this time, mated females are also laying eggs one at a time on leaf edges and flowers. They are looking especially for plants that harbor food for their young – soft-bodied herbivorous insects. The larvae, once they hatch, look a little like tiny greenish worms and usually blend right in. It’s rare to find them unless you really spend effort looking for them, but rest assured, they are busy throughout the summer cleaning plants out, one aphid at a time. When fall arrives, the larvae creep down into the soil to pupate and stay safe through the cold months. When late spring arrives, so do the new adults who mate and start the cycle again.  Margined calligraphers tolerate disturbance well and are found in gardens, meadows, roadsides and other open habitats from Canada through Central America. The genus that they belong to is mostly tropical, but this species is tough and adaptable, able to find habitat in weedy spaces or in perfectly maintained gardens. The only places in North America where you won’t find them are at high altitude and the Arctic, where it’s a little too cold for them. If you’d like to reap the rewards of more margined calligraphers and other syrphid flies in your garden, you can make sure to include diverse, simple flowers. Margined calligraphers aren’t picky, but they are often spotted on flowers that are either open and cup-shaped or have small, clustered blooms like dill and sunflowers. Other favorites include asters, blanketflowers, yarrow, wild rose, potentilla, and even shrubs like dogwood, viburnum, and ninebark. Leaving leaf litter and groundcovers intact in your habitat garden through the fall also protects the pupating phase. Finally, when pests arrive in your garden, consider pest management tactics other than pesticides. Pesticides can harm the species that are trying to manage your pest populations for you.  When it comes to pollinators, margined calligraphers are great reminders that size doesn’t necessarily matter. The more we look, the more we can appreciate the complex interactions and fascinating life cycles of these beautiful garden helpers. Want to learn more about pollinators and how to help them? Contact Butterfly Pavilion’s horticulture department at habitat@butterflies.org!  If you see this pollinator or others around Baseline, take a picture and upload it to Baseline’s iNaturalist page. By doing so, you can be a citizen scientist and help track the diversity and volume of pollinators at Baseline.