Meet the red and fuzzy Ruby Tiger Moth

A Ruby tiger moth, also known as a Ruby moth, lives in the Palearctic region. It is a fluffy reddish-colored moth, and its caterpillar is similar to the Yellow bear caterpillar.

Ruby Tiger Moth species summary

Scientific NamePhragmatobia fuliginosa
Family NameErebidae
Kingdom Animalia
Genus Phragmatobia
HabitatStreams, meadows, downlands, damp areas, gardens
RangePalearctic realm
Host PlantsMostly Eupatorium species
Moth DescriptionReddish, with a few black dots that sometimes touch
Caterpillar DescriptionFuzzy, with gray and yellowish shades

What are the colors of the Ruby Tiger moth?

ruby tiger moth
Ruby tiger moth

The forewings of a Ruby tiger moth have a dark reddish shade and one or two black dots that may touch occasionally. The hindwings are pale pink or bright carmine with black spots that look like discs on the apex regions. The outer and costal regions have black markings.

Both forewings and hindwings are translucent. The patterns of the markings are more prominent on the dorsal view.

When they open their wings, Ruby tiger moths showcase densely scaled and reddish-brown surfaces. On the other hand, their closed wings will show a rose-red base color.

Their thoraxes and abdomens are hairy and a dark shade of reddish-brown. Similarly, their forelegs have red hair. The abdomen has rows of black markings on the entire surface.

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The average wingspan of the Ruby tiger moth is about 1 inch. The measurement of these moths of North America classifies this moth species under the small to medium-sized category.

Larva Physical Description

Ruby tiger moth caterpillar
Ruby tiger moth caterpillar

The Ruby tiger caterpillars have gray and yellowish shades covered with sparse patches of fox-red or black hair. Each segment of their bodies has black dorsolateral disc-shaped spots. The larva resembles the Yellow bear.

Their heads’ colors are a combination of shades of black and brown. During molting, the instars change their body colors to a darker shade of brown or black.

The dark patches of hair are still there until they transition to the pupal stage. At this point, the chrysalis will appear black, while the abdominal region will be yellowish.

Ruby tiger caterpillar vs. Yellow Bear caterpillar

There are several moth species with fuzzy caterpillars similar to the Yellow bear caterpillars (Virginian tiger moth‘s caterpillar), and the Ruby tiger is one of them. Ruby’s caterpillar is darker, yet equally fuzzy.

On the other hand, the Yellow bear is pale, with slightly more prominent fuzz.

Ideal Habitat

Ruby tiger moths typically stay in open habitats, such as:

  • Heathlands
  • Streams
  • Moorlands
  • Shrubby and damp areas
  • Water meadows
  • Downlands
  • Woodland clearings

Common sightings also include:

  • Rivers
  • Weedy spots
  • Dunes
  • Gardens
  • Marshes
  • Farmlands

What are Ruby’s Host Plants?

Female Ruby tiger moths lay their eggs on the host plants indicated below:

  • Eupatorium species plants (Eupatorium perfoliatum)
  • Heather (Calluna)
  • Ironweed (Vernonia)
  • Dandelion (Taraxacum)
  • Sunflowers (Helianthus)
  • European blackberry (Rubus fruticosus L.)
  • Goldenrod (Solidago)
  • Joe-pye-weed (Eutrochium)
  • Plantain

What does a Ruby tiger moth eat?

The larvae will feed on the host plants once they hatch from their eggs. The Ruby tiger larvae are polyphagous regardless of the instar they are in. This means they feed on different types of food plants within a short time interval.

However, adult North American Ruby tiger moths do not eat. They rely on the food and fat they store within their bodies during the larval stage.

Behavior and life cycle

Ruby tiger moths can fly either during the day or the night. They prefer flying in the sunshine. When they fly at night, they are also attracted to light.

These moths have erratic flight patterns. This may be considered one of their defense mechanisms against possible predators.

Adult moths usually breed in the afternoon. Because they only live for about 5 days, they can only mate once during their entire lifespan.

Female Ruby tiger moths lay at least 50 eggs at a time. These eggs hatch after about 10 days. These moths may have one or several broods, depending on location.

Usual Predators

The Ruby tiger moth has the following natural enemies:

  • Birds
  • Wasps
  • Spiders
  • Small mammals

How do they fight off predators?

These moths secrete a poisonous substance with a bitter taste that upsets the stomachs of their predators. Moreover, predators associate the bright colors of the moths’ wings with toxic substances, so they tend to stay away from them.


Ruby tiger moths live in the Palearctic region. This includes most of Europe, Asia, and some parts of North Africa.

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