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
| Lifecycle Stage | Characteristics |
|---|---|
| Egg | Laid in soil |
| Larvae | Parasitic to grasshopper eggs |
| Adult | Attracted to flowers, mates |
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
| Region | Presence |
|---|---|
| Florida | High |
| Texas | Medium |
| Canada | Low |
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
| Method | Pros | Cons |
|---|---|---|
| Physical removal | Chemical-free; immediate | Time-consuming; not suitable for large infestations |
| Natural predators | Environmentally friendly | May not be effective for heavy infestations; dependent on presence of predators |
| Chemical control | Effective for large infestations | Can harm beneficial insects; may impact the environment |
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
Reader Emails
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about red headed blister beetles. Scroll down to have a look at some of them.
Letter 1 – Red Headed Blister Beetle from Malaysia
Subject: Black insect with red head
Location: Penang, Malaysia
June 5, 2016 5:22 am
I came across this bug when I was collecting bugs for a school project at a forest trail near a dam. This insect is black with a red head and has long-ish antennas and legs. Its legs and antennas look sectioned, like bamboo.
It can fly and bite(has wings and pinchers). I fed it some fruit peel and cooked rice and it seems to be eating the rice. Please help me identify the insect.
Signature: Desperate student
Dear Desperate Student,
We immediately recognized your insect as a Blister Beetle in the family Meloidae, and upon searching for the family in Malaysia, we found images of your species on FlickR, but they are not identified to the species level.
We believe we have successfully identified it as Epicauta hirticornis thanks to an image of a mating pair on Sinobug. According to Farangs Gone Wild, it is commonly called the Red Headed Blister Beetle. Blister Beetles should be handled with extreme caution as they can secrete a compound cantharidin that may cause blistering in human skin.
