A brilliant blue butterfly perching with spread wings. Eastern Tailed Blue Butterfly. Everes comyntas. Cupido comyntas.

Wild Facts About The Eastern Tailed-Blue Butterfly

ByChristine Wild Animals

How To Identify Eastern Tailed-Blue Butterflies

  • Wingspan: 0.5 – 1.0 inches (1.3 – 2.5 cm)
  • Above:
    • Males and females differ in appearance.
      • Males are bright, solid blue. Wings are rimmed in thin band of brown.
      • Females are either dull blue (spring-time females) or dark, slate gray (summer and fall females).
    • Each hind wing of both sexes has 1-3 small, orange and black spots, and a single, short, thread-like tail.
  • Below:
    • Males and females are similar in appearance.
    • Wings are pale gray, with curved rows of small black spots and bars.
    • Each hind wing has 1-3 small, orange and black spots, and a single, short, thread-like tail.

How To Find Eastern Tailed-Blue Butterflies

  • Flight Season: End of March through October.
  • Look for adult Eastern Tailed-Blue Butterflies in open, sunny areas with low-growing vegetation, like meadows, fields, and overgrown lawns. They are also common in disturbed areas like power line cuts and along railroads.
  • Adult butterflies feed on nectar from a wide variety of flowering plants, especially:
    • White Sweet Clover (Melilotus alba)
    • Butterfly Weed (Asclepias tuberosa)
    • Daisy Fleabane (Erigeron annuus)
  • These butterflies like to fly low, almost hugging the ground, and have a fast, fluttery, up and down flight.
  • They can be hard to see when perched because of their small size and relatively inconspicuous ventral wing surface coloration.
    • The best way to spot these butterflies is to wait motionless in a likely habitat, like a flowery meadow, and watch carefully for flitting motion inches above the tops of the plants. Follow the butterfly with your eyes until it lands.
  • Male Eastern Tailed-Blue Butterflies also like to “puddle” or gather around damp soil to drink salts and other minerals.
Eastern Tailed Blue Butterfly. Everes comyntas. Cupido comyntas. Insect. Photograph taken and design created by the author. Copyright © 2025 Now I Wonder. All rights reserved.
Eastern Tailed Blue Butterfly Everes comyntas Cupido comyntas Insect Photograph taken and design created by the author Copyright © 2025 Now I Wonder All rights reserved

Eastern Tailed Blue Butterflies Prefer Peace And Quiet

  • A study conducted in Ontario, Canada that researched the impact of butterfly assemblages of human disturbance found that:
    • Out of 26 observed butterfly species, 15 were absent from disturbed sites.
    • 28% of the butterfly species were classified as “disturbance adaptable” and 58% as “disturbance avoiders”.
    • One time disturbances like mowing reduces species richness and total abundance by up to 80%.
    • Eastern Tailed Blue butterflies were found to be “disturbance avoiders”.
Eastern Tailed Blue Butterfly. Everes comyntas. Cupido comyntas. Insect. Photograph taken and design created by the author. Copyright © 2025 Now I Wonder. All rights reserved.
Eastern Tailed Blue Butterfly Everes comyntas Cupido comyntas Insect Photograph taken and design created by the author Copyright © 2025 Now I Wonder All rights reserved

When A Little Is Better Than A Lot

  • Eastern Tailed Blue butterflies are habitat generalists and prefer grassland habitats, which is likely why mowing and/or otherwise disturbing natural areas so disrupts their population.
  • But many grassland ecosystems rely on disturbances to thrive, because they evolved under selective pressures such as fire and grazing by large herds of herbivores.
  • One study tested the effects of fire and grazing on butterfly species richness and population density in a grassland landscape in central United States.
    • Researchers sampled butterfly abundance in pastures that received one of three treatments:
      • Patch-Burn-Graze: rotational burning of three distinct patches of pasture and moderate grazing by cattle,
      • Graze-and-Burn: burning the entire pasture every three years and moderate grazing by cattle,
      • Burn-Only: Burning the entire pasture every three years but no grazing by cattle.
    • Populations of Eastern Tailed Blue butterfly population density was highest in the patch-burn-graze treatment (Moranz et al. 2012, https://doi.org/10.1007/s10531-012-0330-2).
Eastern Tailed Blue Butterfly. Everes comyntas. Cupido comyntas. Insect. Photograph taken and design created by the author. Copyright © 2025 Now I Wonder. All rights reserved.
Eastern Tailed Blue Butterfly Everes comyntas Cupido comyntas Insect Photograph taken and design created by the author Copyright © 2025 Now I Wonder All rights reserved

Sorting Out The Gossamer-Wings

  • Despite being classified in different genera, Eastern Tailed Blue butterflies can be mistaken for another gossamer-winged butterfly, the Gray Hairstreak (Strymon melinus) at first glance.

Under Wing Comparison

  • The underside (ventral) surface of the wings of both species are mostly pale silver-gray and decorated with small black markings.
    • The Eastern Tailed Blue’s black markings are outlined in white and scattered across the wing surface.
      • In contrast, the black markings on Gray Hairstreaks are arranged in a single, zig-zag row, sometimes edged with orange on the inner edge.
  • Both species also sport at least one prominent orange and black spot along the trailing edge of each hind wing.
    • Eastern Tailed Blues can have two orange and black spots.
      • Gray Hairstreaks have only one orange-capped black spot and it tends to be larger than those of the Eastern Tailed Blue butterfly.

Upper Wing Comparison

  • While the upper (dorsal) wing surface of male Eastern Tailed Blue butterflies is vibrant blue, female Eastern Tailed Blue butterflies have gray-brown wings.
    • Both sexes of Gray Hairstreaks have gray wings but their wings are darker and pure gray overall.
  • Both species sport an orange-capped black spot in the border of each hind wing and have tails on their hind wings.

Scientific Classification

Kingdom

Animalia (animals)

Phylum

Arthropoda (arthropods)

Class

Insecta (insects)

Order

Lepidoptera (butterflies and moths)

Family

Lycaenidae (gossamer-winged butterflies)

Genus

Cupido

Species

C. comyntas (formerly E. comyntas)

Scientific Name

Cupido comyntas (formerly Everes comyntas)

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Christine
Christine is the creator and author of NowIWonder.com, a website dedicated to the animals and plants that share our world, and the science that helps us understand them. Inspired by lifelong exploration and learning, Christine loves to share her knowledge with others who want to connect with wild faces and wild spaces.
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