The cinnabar moth (Tyria jacobaeae) is a brightly colored moth found in Europe, parts of Asia, and introduced to parts of North America and New Zealand. Its vivid red and black coloring makes it stand out against green vegetation. Let’s explore just how rare this eye-catching moth is.
The cinnabar moth gets its common name from the red mineral cinnabar due to the distinctive red coloration of the moth’s forewings. The red bands on the moth’s wings serve as a warning signal and advertisement to predators that the moth is toxic and distasteful. This type of coloration in insects is known as aposematic coloration. The black and red warning colors of the cinnabar moth likely contribute to its rarity by deterring predators.
Some quick facts about the cinnabar moth:
– Scientific name: Tyria jacobaeae
– Wingspan: 34-44 mm
– Flight time: May to August (one generation per year)
– Caterpillar host plants: ragwort and groundsel
– Toxicity: Caterpillars accumulate toxins from host plants
Geographic Range and Habitat
The cinnabar moth has a wide distribution across parts of Europe, Asia, and North Africa:
|Britain, Ireland, France, Belgium, Netherlands, Germany, Switzerland, Austria, Italy, Scandinavia, Poland, Baltic states, Russia, Spain, Portugal
|Turkey, Israel, Lebanon, Russia, India, Nepal, China, Korea, Japan
|Morocco, Algeria, Tunisia
It has also been introduced to parts of North America, Australia, and New Zealand where its caterpillar host plants have been introduced. In North America, it is established along the west coast and parts of the northeastern United States and southeastern Canada.
The cinnabar moth inhabits open grassy areas where its host plants ragwort and groundsel grow. Prime habitat includes meadows, pastures, roadsides, railway embankments, and waste ground. It is considered a short-grassland species, not inhabiting overgrown areas. The moths are low-flying and rarely found far from larval food plants.
Population and Conservation Status
Despite its wide range across three continents, the cinnabar moth is quite localized and occurs in colonies where conditions allow. The population density fluctuates from year to year. Population sizes tend to be highest following warm, dry summers. Cool, wet weather tends to decrease survival rates.
In Britain, the cinnabar moth has undergone significant declines over the past 40 years, disappearing from parts of southern England. Possible reasons for the decline include climate change decreasing warm weather favorable for breeding, as well as loss of grassland habitat. The moth is considered a Priority Species for conservation in the UK.
Across Europe, the cinnabar moth is considered near threatened or declining in over half of the countries where it is found. However, due to its large geographic range, it is not considered globally threatened. Exact population sizes are unknown but the moth is described as local and scattered across its range, rarely abundant. It is generally much more restricted than its host plants.
Conservation recommendations include protecting open grassland habitats from development or reforestation. Allowing ragwort to grow, rather than eliminating it, can provide habitat for cinnabar moth colonies. Limiting insecticide use will also help protect moths. More research is needed to determine the impact of climate change on populations.
Life Cycle and Behavior
The cinnabar moth is univoltine, meaning it has one generation per year. It overwinters as a pupa, emerging as an adult moth in spring or early summer. After mating, the female lays batches of yellow eggs on the underside of ragwort leaves. Young caterpillars are black and gray. As they grow over 14-21 days, they develop the bright black and orange warning colors.
|Pupa (in cocoon)
|300+ days overwintering
The caterpillars feed communally on ragwort leaves. They are gregarious and congregate in large groups. If food is scarce, the caterpillars will march in processions en masse to new plants, led by the oldest caterpillars. The caterpillars sequester alkaloid toxins from the ragwort, making themselves distasteful.
The adult moth does not feed. It lives only to mate and reproduce. Females lay about 100-200 eggs over their short two week lifespan. Males fly during the day to seek out females.
Peak flight time is late June to early July. However, the exact timing varies based on weather and latitude. Further north, the flight period starts later. In cold summers, emergence may be delayed.
Predators and Defense
The cinnabar moth’s bright aposematic coloration warns predators such as birds that it is toxic. Additionally, the caterpillars adopt a defensive pose when disturbed, raising their heads and front halves off the leaf. This reveals the bright red hind end as a warning signal.
Some specialized predators have adaptations to feed on cinnabar moth caterpillars and avoid the toxins. These include:
|Adaptations to Toxins
|Cinnabar moth tachinid fly (Cistogaster cinnabarinae)
|Stores toxins in adult stage but does not transfer to larvae
|Ichneumon wasp (Gelis agilis)
|Feed only on young non-toxic caterpillars
|Brown lacewing (Micromus variegatus)
|Able to sequester alkaloids with minimal harm
Birds are also known to feed cinnabar moth caterpillars to their young, likely because the chicks are more tolerant of the toxins.
Relationships to Humans
The cinnabar moth does not directly affect human health or agriculture. Its caterpillars preferentially feed on ragwort and groundsel, which are considered weeds. It does not cause significant damage to wildflowers or crops. Occasionally gardens planted with ragwort as an ornamental may experience defoliation from cinnabar moth caterpillars. But the effects are typically minor.
For collectors, the cinnabar moth is a desirable species due to its beautiful red and black wing patterns. Specimens must be captured responsibly and ethically. Collection should be avoided in areas where the moth is rare or threatened.
Many photographers appreciate the opportunity to photograph the cinnabar moth in grasslands where it lives. Its vibrant colors and interesting behavior, such as the communal marching of caterpillars, provide appealing photographic subjects.
For scientists, the cinnabar moth serves as an important model species in ecological studies of mimicry, aposematism, and predator-prey interactions. The moth-tachinid fly relationship helps reveal how coevolution shapes defenses and counter-adaptations.
Overall, the cinnabar moth is an intriguing species, bringing beauty to summer days and grassland habitats. While human actions have caused some declines, conserving remaining populations of this colorful creature should remain a priority.
In conclusion, the cinnabar moth has a relatively wide distribution across parts of Europe, Asia, and North Africa but is quite localized and scattered even within those regions. Exact population sizes are unknown but the moth is described as uncommon to rare throughout its range, occurring in colonies where habitat conditions allow.
It has undergone significant declines in Britain, disappearing from parts of its former range. Across Europe it is considered near threatened or declining in over half of the countries where found. Habitat loss and climate change are major threats to remaining populations.
Protecting open grassland areas where ragwort grows can help provide refuges for colonies. Limiting insecticide use, allowing some growth of ragwort, and further research into the impacts of climate change are recommended conservation actions. The cinnabar moth remains a priority species for conservation in the UK and parts of Europe due to its sensitivity.
While globally not considered endangered currently, the cinnabar moth is rare enough across its range to warrant continued monitoring and habitat protection for this beautiful and fascinating species.