Green Blister Beetle: Essential Facts and Tips

The green blister beetle is a fascinating insect belonging to the Coleoptera family Meloidae, known for its vibrant, colorful appearance.

These beetles are predators of bee and grasshopper egg masses in their larval stage and feed on flowers and sometimes leaves of various plant species as adults.

These beetles come in other colors such as blue, grey, and spotted, but the green variety is particularly captivating due to its metallic sheen.

When comparing different species, the green blister beetle is similar to its relatives in size, ranging from 1/3 to 2/3 inches long.

However, all blister beetles share a distinct feature: a narrow “neck” that contrasts with the broader head and abdomen.

Green Blister Beetle: The Basics

Taxonomy and Classification

Green blister beetles belong to the family Meloidae and are a type of blister beetle commonly found across the United States and Canada.

These insects are known for their elongated, narrow, and soft bodies and typically belong to species such as the three-striped, grey, and black blister beetles¹.

Physical Features: Colors, Sizes, and Body Shapes

Green blister beetles can exhibit various colors, including black, gray, and even metallic sheens like purplish-green in the case of Nuttall’s blister beetle².

The body length of these beetles usually ranges from 0.5 to 1.25 inches³.

Some notable physical features of green blister beetles are:

• A narrower visible part of the thorax than the head and abdomen³
• Front wings that do not extend over the tip of the abdomen³
• A distinctive narrow “neck” that contrasts with the broader head and abdomen⁴

The fluids within these beetles contain a chemical that can cause skin irritation if touched, hence the name “blister beetle”.

Life Cycle and Reproduction

Egg Stage

The life cycle of the green blister beetle starts with the egg stage. Female beetles lay their eggs in shallow soil cavities during the summer.

The eggs hatch after spending around 7 to 10 days¹ in this stage.

Larval Stage

The next stage in the life cycle is the larval stage, which is mainly focused on feeding and growth.

The larva usually targets grasshopper eggs as their primary food source. In the case of the margined blister beetle, the larva is known to feed on legumes². During this stage:

• Larvae undergo several molts
• They develop and grow for up to several weeks

Adult Stage

After completing the larval stage, the beetle undergoes pupation. The adult blister beetle emerges after about 2 weeks³.

The adult stage mainly consists of feeding, mating, and laying eggs. 

Habitat and Distribution

Geographical Range

Green blister beetles are commonly found in North America, from Mexico to Canada.

They are also found in the United Kingdom, the West Indies, South and Central America, and northern Ghana.

These beetles favor warmer climates, so their distribution is more prevalent in the southern parts of these countries.

Where They Can Be Found?

Green blister beetles are typically found around:

• Flowers: They feed on flower petals and nectar.
• Crops: They can infest various crops, especially alfalfa and legumes.
• Plants: They generally consume leaves, flowers, and soft plant tissue.

Alfalfa and Agriculture

In the agricultural sector, green blister beetles are particularly concerning for alfalfa production. They are attracted to this crop, especially during blooming.

The presence of beetles in alfalfa can cause problems for animals, such as horses and livestock, which may consume the toxic insects along with the plants.

Examples of places where you may find green blister beetles:

• Gardens
• Fields
• Agriculture lands

Diet and Predation

What Green Blister Beetles Eat

Green blister beetles, also known as Epicauta species, primarily feed on plants. Some common targets include:

• Flowers
• Leaves
• Alfalfa hay
• Various vegetable crops

These insects can be pests to crops and, in certain situations, can be harmful to livestock and poultry.

Natural Predators

The green blister beetle has several natural predators that help control their population. These include:

• Birds
• Frogs
• Lizards
• Spiders
• Assassin bugs

While the predators help to reduce the number of green blister beetles, it is still necessary to implement pest control measures to protect crops and livestock from their harmful effects.

Effects on Livestock and Poultry:

Livestock such as cattle, sheep, and poultry can suffer severe damage to their urinary and gastrointestinal tracts if they ingest cantharidin, a toxic compound found in blister beetles.

This can occur if the beetles are crushed and mixed into alfalfa hay or other feed sources.

To keep the damage from green blister beetles in check, it is important to use integrated pest management practices and support their natural predators in the ecosystem.

Interesting Facts and Uses

Historical Uses

The green blister beetle is a part of the blister beetle family, which has some interesting historical uses.

One well-known member of this family is the Spanish fly, which was once used as an aphrodisiac due to its ability to release a chemical called cantharidin¹.

However, high doses of cantharidin can be harmful and can lead to severe health issues².

Surprising Discoveries

• Blister beetles contain a toxin called cantharidin³.
• This toxin can cause skin irritation and blisters, hence the name “blister beetle”⁴.

Conclusion

Green blister beetles, part of the Meloidae family, are captivating insects recognized for their vibrant colors and unique physical features.

Predatory in their larval stage, they target bee and grasshopper egg masses, transitioning to a diet of flowers and plant leaves as adults.

Their name derives from the skin-irritating chemical they contain, cantharidin. While they exhibit a range of colors, the metallic sheen of the green variety stands out.

Distributed mainly across the U.S. and Canada, these beetles play a significant role in the ecosystem, but their toxic nature demands caution.