The tiger moth is a remarkable creature with its unique appearance and intriguing adaptability, both the adults and their hairy caterpillars. Join us as we explore the intriguing world of the tiger moth, unraveling its interesting behaviors, survival strategies, and life cycle
Class: Insecta
Order: Lepidoptera
Family: Erebidae
Subfamily: Arctiinae
They are hairy
The tiger moth is a diverse group of moths with around 11,000 species found globally, including 6,000 species in the neotropics. This type of moth was previously classified as Arctiidae within the superfamily Noctuoidea. However, it has recently been reclassified as a subfamily (Arctiinae) within the family Erebida.
The subfamily Arctiinae includes several tribes, such as Arctiini, Lithosiini, and Syntomini, which were previously classified as subfamilies. Under these tribes, there are many subtribes.
These moths are known for their distinctive appearance with many color and pattern variations, over 500 named aberrations. Most of them have dark wings with red or orange spots and white stripes, forming striking geometric patterns. The abdomen is often striped, giving them their name. However, some tiger moth species come with a light or white appearance, like the ones from the subtribe Spilosomina.
Many species have a tymbal organ on their metathorax, which vibrates to produce ultrasonic sounds.
Tiger moth caterpillars are known for their distinctive hairy appearance. They are usually heavily armored with urticating and barbed bristles. That’s why they are often called “woolly bears” or “woolly worms”. These caterpillars have a wide variety of colors, including white, yellow, orange, red, and black, often in bold patterns like stripes, spots, or bands.
Tiger moths habitat
Tiger moths are found in coastal areas of eastern Australia, particularly around flowers, water, and in the air. Some species, like the garden tiger moth, are found in northern parts of the United States, Canada, and Europe.
They have a poisonous diet
The tiger moths have different diets at different stages of their life cycle. The adult moths are nectarivorous, primarily consuming floral nectar from flowers. Their caterpillars, on the other hand, are herbivores and generalists, eating a wide variety of plants without much specialization. They consume plants such as asters, dandelions, clover, and goldenrod, as well as toxic plants like foxglove, which allows them to accumulate toxins for defense against predators later in life.
They have cool defense mechanisms
Tiger moths have quite a few natural predators like birds, reptiles, or bats. Their larvae are attacked by green lacewing caterpillars or adult Audouin’s night-stalking tiger beetles. These species employ various defense mechanisms to protect themselves from predators.
The first strategy is to use their bright colors and patterns, serving as a warning signal to predators that they are distasteful or toxic. This warning signal is often associated with chemical defenses, making predators more likely to avoid them.
If this doesn’t work, they will produce chemical secretions from their abdomens and thoracic glands to deter predators. This defense mechanism can be expressed in adults and their eggs and caterpillars. These secretions are targeted against specific predators, such as invertebrates (from the abdomen) and birds (from the thoracic glands).
Some tiger moth species extract the toxin from their diet, the others (like the wood tiger moth) produce their chemical defenses de novo themselves. However, deploying defensive secretions can come at a cost to the moths’ reproductive success. For example, male wood tiger moths that release defensive secretions have lower reproductive success compared to those that do not.
Bats are major predators of moths like hawk moths, but not the tiger moths. Despite both being active at night, these insects still have their own way of dealing with bats. They make clicking sounds that interfere with a bat’s echolocation, confusing it and making it harder for the bat to locate them.
Tiger moth caterpillars are covered in long urticating hairs that are irritating when touched, providing protection from predators like beetles. When disturbed, larvae curl into balls and drop from vegetation into the ground litter below. They also excrete feces and liquid matter when threatened, a common defense mechanism among larvae of many butterflies and moths.
Life cycle
During the warmest parts of sunny days, females sit on low-lying vegetation and release pheromones to attract males to come to them. Their copulation lasts between 2 and 5 hours, after which mating pairs separate and females seek oviposition sites.
Females begin depositing eggs within a day of mating, laying their egg clusters of 10-400 on low-lying vegetation, often on the undersides of leaves. These eggs are small, round, and pearly white. After 4-21 days, the eggs hatch with larvae immediately independent and often eat some or all of their egg cases as a first meal.
Larvae go through 5 instar stages, growing in size and darkening in color with each molt. Early instar larvae feed on the undersides of leaves, while later instars prefer nocturnal feeding. Fully grown larvae are 1.5-2 cm long, dark gray with orange spots, and covered in urticating hairs that protect them from predators.
These caterpillars spend about 4 to 7 days in each of the first four instars, typically reaching the fifth instar by early to mid-July. But in the fifth instar, they stay 40 to 60 days.
In late summer or fall, mature larvae pupate inside silk cocoons mixed with their own hairs. Pupae overwinter for 6 to 7 months in leaf litter and emerge as adults the following spring. The lifespan of the tiger moth lasts only 2-3 weeks. The entire life cycle is typically completed in about one year, with some species having multiple broods per year in warmer climates.
