There are a few species of moths that are brown with white spots. To identify the specific moth, it is helpful to consider the size, shape, and pattern of the spots as well as the location and time of year the moth was spotted.
Common Brown Moths with White Spots
Some of the most common brown moths with white spots include:
- Speckled Wood Moth
- Muslin Moth
- Angle Shades Moth
- Dot Moth
- Brown-tail Moth
- European Gypsy Moth
Let’s take a closer look at the distinguishing features of each of these moths:
Speckled Wood Moth
The speckled wood moth (Pararge aegeria) is a common day-flying moth found throughout much of Europe. As the name suggests, it has brown, speckled forewings with cream and brown markings. The spots on the forewings vary in size and are concentrated around the edges. The hindwings are a plain orange-brown color with no markings. These moths have a wingspan of 3.5-4.5cm.
Muslin Moth
The muslin moth (Diaphora mendica) is found throughout North America and Eurasia. The forewings are mottled brown and gray with small white speckles. When at rest, the front wings are angled back, exposing the plain brown hindwings. The muslin moth has a wingspan of 4.5-6.5cm.
Angle Shades Moth
The angle shades moth (Phlogophora meticulosa) is a fairly large European moth with a wingspan of 4.5-6cm. As the name suggests, the forewings are angular with deep brown coloring and white spots at the tips. The spots vary in size from small speckles to larger blotches. When at rest, the mottled brown and gray hindwings are exposed.
Dot Moth
The dot moth (Melanchra persicariae) is aptly named for the distinctive white dot located on each forewing. The remaining areas of the forewings are brown with a faint pattern. The hindwings are paler brown. These moths are found throughout Europe, Asia, and North America and have a wingspan of 3.5-4.5cm.
Brown-tail Moth
The brown-tail moth (Euproctis chrysorrhoea) is an invasive species in North America, introduced from Europe. The forewings are light brown with white spots along the outer margins. The lower half of the hindwings are also whitish. They have a wingspan of 3-4cm. The brown-tail moth caterpillars have poisonous hairs that can cause dermatitis in humans.
European Gypsy Moth
Though notorious for being a destructive pest, the European gypsy moth (Lymantria dispar) is also a brown moth adorned with white spots. The males have brown forewings with black zigzag markings and small white spots. Females have larger, more feathered wings that are white and brown. These moths can have a wingspan of up to 5cm.
Identifying Features
When trying to identify a spotted brown moth, pay close attention to the following features:
- Wingspan – The moth’s wingspan can offer a clue as to the species.
- Spot size – Are the spots small speckles or larger blotches?
- Spot location – Where on the wings are the spots concentrated?
- Spot pattern – Are the spots randomly scattered, in rows, or clustered?
- Resting posture – The angle of the wings when at rest can aid identification.
- Body color – Is the thorax and abdomen also brown?
- Antennae – The length, thickness, and coloring of the antennae can also help distinguish species.
Range and Habitat
The geographic location and habitat where the moth was found can provide helpful clues about its identity. Here are some notes about range and habitat preferences:
- Speckled wood moths are found in woodlands throughout Europe.
- Muslin moths live throughout temperate regions of North America and Eurasia in forested areas.
- Angle shades moths reside in Europe and are common in gardens, woods, and grasslands.
- Dot moths inhabit open grassy areas, gardens, and woods in Europe, Asia, and North America.
- Brown-tail moths are invasive in the northeastern United States and southeastern Canada.
- European gypsy moths are an invasive species in the eastern United States and Canada.
Flight Season
The time of year when the moth is spotted can also provide clues about its identity:
- Speckled wood moths are spotted from April-October with peak numbers in June-August.
- Muslin moths fly from May-August with peak populations in summer months.
- Angle shades moths fly from May-October with highest populations in late summer.
- Dot moths are nocturnal and fly from June-August.
- Brown-tail moths have one generation per year and fly from mid-summer through fall.
- European gypsy moths have one generation per year and are most active from mid-July through August.
Caterpillar Host Plants
Identifying food plant preferences for the caterpillars can also help pinpoint the moth species:
- Speckled wood moth caterpillars feed on grasses.
- Muslin moth larvae eat the leaves of various broadleaf trees and shrubs.
- Angle shades moth caterpillars feed on a wide variety of plants, including nettle, hops, dandelion, dock, and currants.
- Dot moth larvae feed on chickweed, knotgrass, and other low-growing herbaceous plants.
- Brown-tail moth caterpillars prefer cherry, apple, rose, ash, oak, and other broadleaf trees and shrubs.
- Gypsy moth larvae have a very broad host range but prefer oak, willow, and aspen.
Conclusion
In summary, identifying a brown moth with white spots requires a close examination of size, wing markings, geographic location, flight season, and caterpillar feeding preferences. With careful observation and a process of elimination, even novice moth watchers can learn to correctly identify some of the most common species.
Consulting a field guide or moth identification website can also help provide additional details to confirm the moth species. Proper identification is not only satisfying but can aid scientists and conservation efforts by improving knowledge about moth diversity and distributions.
Moth Identification Table
| Species | Wingspan | Spot Size | Range | Flight Season | Caterpillar Hosts |
|---|---|---|---|---|---|
| Speckled Wood Moth | 3.5-4.5cm | Small spots | Europe | April-October | Grasses |
| Muslin Moth | 4.5-6.5cm | Small speckles | North America, Eurasia | May-August | Broadleaf trees, shrubs |
| Angle Shades Moth | 4.5-6cm | Small and large spots | Europe | May-October | Wide variety, including nettle, hops, dandelion |
| Dot Moth | 3.5-4.5cm | One large dot per wing | Europe, Asia, North America | June-August | Chickweed, knotgrass, herbaceous plants |
| Brown-tail Moth | 3-4cm | Small-medium marginal spots | Invasive in northeastern U.S. and southeastern Canada | Mid-summer through fall | Cherry, apple, rose, oak |
| European Gypsy Moth | Up to 5cm | Small spots | Invasive in eastern U.S. and Canada | Mid-July through August | Oak, willow, aspen |
