Blister Beetles

These colorful insects belong to the Meloidae family of beetles and are commonly known as blister beetles. There are around 3,000 different species of blister beetles worldwide, and 145 species known in Egypt. They earned their common name from their defense mechanism – a secretion of a blistering agent, cantharidin. Getting this on your skin would cause an irritating reaction, but cantharidin is also used medicinally to remove warts.

Like all beetles (Order Coleoptera), they have hardened front wings that meet in a straight line in the center of their backs. Meloids, or blister beetles, are elongate in shape and the sides of their body are parallel. The pronotum, the hard shield-like covering on their thorax, is usually narrower than the head, and the tarsal claws are split in two lengthwise. Blister beetles are often conspicuous, with outstanding and noticeable colors. This announces their toxicity to potential predators.

Blister beetles lay their eggs in masses under stones, in the ground, or on the food plants of the adults. The larvae are insectivorous and are predators of grasshopper eggs and immature bees that they consume after entering the nests. Adults can live three months or more and feed on the nectar and pollen of a diverse range of plants – from the amaranth, aster, legume, and nightshade families. Some blister beetles also feed on foliage, leaves, and flowers and can be destructive to gardens and crops. In Egypt, for example, Meloe rugosus is a pest on agricultural crops in the western desert and feeds on fava bean, wheat, peas, alfafa, and onion plants.

Adult blister beetles are seldom seen. Have you ever spotted one while wandering through wadis in South Sinai?

Darkling Beetles

Even if you spot no other critter while wandering through wadis, you are almost guaranteed to see at least one darkling beetle, likely scurrying across the sand to find safety under a desert plant.

Darkling beetles are what we commonly call the beetles that make up the Tenebrionidae family of beetles (Order Coleoptera). There are more than 20,000 species of darkling beetles worldwide. In Egypt, there are about 400 different species, around 120 of those can be found in Sinai. I believe most of the darkling beetles that I have photographed belong to the Adesmia genus, but I have not been able to narrow down the identification any further.

Though most darkling beetles are dark in color, they are actually named for their nocturnal habits. A few beetles are colored or patterned, sometimes with red. Many of the larger species, like the ones pictured here, are flightless. The elytra (the rigid, forewings) are fused.

The domed shape of these darkling beetles, particularly those in the Adesmia genus, remind the Jebeliya Bedouin of donkeys. They refer to them as ‘uwir al banat, or “newborn donkey for girls”. 1

Darkling beetles are common in desert areas, where they fill an ecological niche as plant scavengers. They are generalist omnivores though, meaning they can feed on a wide variety of plants and animals. As both larvae and adults, they feed on fresh or decaying plant matter like leaves or rotting wood. They will also eat fungi, dead insects and larvae. You will find darkling beetles living under logs and stones, in termite and ant nests, in plant debris, and in the dry dung of animals.

I always enjoy coming across these beetles while I’m wandering. They are entertaining to watch as they scuttle out of the way or over rocks. They are a good reminder that I am not alone out there, that there is a variety of wildlife surviving in our desert wadis.

On a lunch break in Wadi Lebba a few years ago, a darkling beetle was brave enough to approach our picnic spot so I shared a bite of orange with him.

If you’ve not spotted a darkling beetle on your wanders yet, watch the ground a few meters in front of you on your next hike. Or stop for a break near some plants. If you’re quiet, you might even hear them scrambling around.

References:

1- Zalat, S., & Gilbert, F. (2008). Gardens of a Sacred Landscape: Bedouin Heritage and Natural History in the High Mountains of Sinai. Cairo: The American University in Cairo Press.

Beetles in Sinai

Beetles, forming the largest order of insects with nearly 400,000 identified species, account for nearly 40% of all insects. So I guess it’s no surprise that my collection of beetle images is one of my largest!

Beetles in Sinai

Here’s what you can see in this sampling:

Blister Beetle
Carpet Beetle 
Darkling Beetle
Red Palm Weevil
Seven-spotted Ladybug
Hairy Rose Beetle
Jewel Beetle
and a few unidentified beetles (the blue/green ones…can anyone help with an ID?)