Red Headed Blister Beetle: Essential Facts Explained

The red-headed blister beetle (Epicauta hirticornis) is a fascinating insect with some unique characteristics.

This beetle can be identified by its striking red head, soft elongated body, and the cantharidin toxin it produces.

The cantharidin in their body fluids can cause blisters on human skin if mishandled, and even life-threatening inflammations in horses and livestock.

These beetles can be found in various parts of the United States and Canada, with their population generally peaking around mid-summer.

They are often found in flowering alfalfa hay and their presence is sometimes correlated with grasshopper populations.

While the red-headed blister beetle is not the only species of its kind, it offers a fascinating glimpse into the world of blister beetles and their impacts on agriculture and livestock.

Red Headed Blister Beetle: Identification and Characteristics

Appearance

The Red Headed Blister Beetle, also known as the Master Blister Beetle (Lytta magister), is a member of the Meloidae family, common in North America, particularly in the Southwest. This beetle is characterized by:

• A bright red head
• Black or dark-colored body and wings
• Long legs
• Thread-like antennae

The body shape of Red Headed Blister Beetles is distinct, with a narrow thorax and wider head, as well as soft, leathery bodies¹.

Family Meloidae

Blister beetles belong to the family Meloidae and are known for their ability to produce blisters on contact with human skin due to their hemolymph².

They can be found in various colors, sizes, and body shapes. Some common features include:

• Soft bodies
• Leathery wings
• Beaded, thread-like antennae

Life Cycle and Reproduction

Egg to Larvae

• Female blister beetles lay eggs in soil
• Eggs hatch within 7-10 days

The journey of a red-headed blister beetle starts as an egg.

Female beetles lay these eggs in shallow soil cavities during the summer. Once an egg is laid, it remains for 7 to 10 days before hatching into a larva.

Larval Stage and Parasites

• Larvae are parasites to grasshopper eggs
• Go through several stages of development

In the larval stage, the young blister beetle is parasitic to grasshopper eggs and feeds on them.

As they grow, larvae transition through several stages of development known as instars.

These developmental stages allow the larva to grow and prepare for its eventual transformation into an adult beetle.

Adult Stage and Mating

• Attracted to flowers for food
• Mating occurs in adult stage

Once the beetle reaches its adult stage, it abandons its parasitic lifestyle and becomes attracted to flowers for food.

Adult beetles participate in mating to ensure the continuation of their species.

Comparison Table

Habitats and Feeding Habits

Host Plants

Red-headed blister beetles feed on a variety of host plants, such as:

• Alfalfa
• Potato
• Tomato

These insects are also known to consume grasshoppers, weeds, and vegetables¹.

Floral Preferences

Blister beetles have a specific preference for flowers. They tend to be attracted to:

• Legumes
• Shrub blossoms
• Nectar-rich flowers

Notable examples include beet and Sonoran desert flowers².

Regional Presence

Red-headed blister beetles are found in various regions, including:

• Florida
• Texas
• Canada

Each region has its unique habitat characteristics that influence the beetle’s distribution.

Impact on Agriculture and Gardens

Crop Damage

Red-headed blister beetles, along with striped and margined blister beetles, can cause considerable damage to crops.

They feed on various plants such as alfalfa, pigweed, and legumes. These pests may defoliate crops, impacting their growth and yield.

Livestock Health

Blister beetles are a major concern for livestock, particularly horses, due to the presence of a toxic substance called cantharidin in their bodies.

When ingested by animals, blister beetles can cause serious health issues or even death. As reported by NDSU Extension, the ingestion of 25 to 300 beetles can be lethal to an average-sized adult horse.

Livestock health risks with blister beetles:

• Horses: highly susceptible to blister beetle poisoning
• Sheep and cows: less susceptible, but still at risk

Garden Pest Management

Managing red-headed blister beetles in gardens can be challenging. Some methods to control their population include:

• Physical removal: Hand-picking and removing beetles from plants
• Natural predators: Encouraging birds and other predators in your garden to reduce beetle numbers
• Chemical control: Using insecticides when needed, but being cautious not to harm beneficial insects

Toxicity and Cantharidin

Direct Contact

When in direct contact with a red-headed blister beetle, cantharidin can cause skin irritation and blisters. A few symptoms include:

• Pain: The skin can become painful to touch upon contact with a beetle.
• Welts: Raised, red welts may form on the skin after being in contact with a beetle.
• Blisters: Cantharidin-induced blisters may develop over time.

Symptoms and Treatment

Exposure to the red-headed blister beetle, Lytta magister, may cause symptoms such as:

• Sweating
• Swelling
• Lesions

Upon contact with these beetles, it’s crucial to wash the affected area with soap and water to minimize symptoms.

If you experience eye irritation, consult an eye doctor to evaluate possible damage. In some cases, antibiotics may be necessary to treat skin infections or lesions.

Conclusion

The red-headed blister beetle, with its distinctive appearance and potent toxin, plays a unique role in North American ecosystems.

Found across the United States and Canada, these beetles have a life cycle that intertwines with grasshoppers and impacts agriculture.

While they pose risks to crops and livestock, especially horses, understanding their habits and life cycle can aid in effective management.

From their vibrant colors to their toxic nature, these beetles truly offer a glimpse into the intricate world of insects.

Footnotes