Saturday, May 28, 2016

Tarantula Hawk

We were working in the yard today and noticed a VERY large dark insect flying around our desert milkweed plant. It had a heavy black body with an iridescent blue shine, and beautiful rust-colored wings. We immediately recognized it as a Tarantula Hawk wasp.

Following the wasp over to the milkweed plant, we saw that there was a second Tarantula Hawk already on the plant. It was busily crawling over the creamy white flower heads, drinking nectar from the blossoms. We soon found a third wasp on the back side of the plant, also enjoying the nectar. As we watched, 2 other Tarantula Hawks landed on the milkweed plant, making a total of 5 of these beautiful insects.

Two of the wasps were about the size of the last 2 joints of my pinky finger. The other 3 were slightly smaller.

There are 250+ species of these spider wasps that live worldwide. Each of these specializes in hunting a particular spider species. Fifteen spider wasp species occur in the US, and 9 of those are desert dwellers.

These Tarantula Hawks spend much of their time dining on nectar and pollen from desert plants such as milkweed and mesquite.

They are diurnal, but avoid being out during the very hottest part of the day. Roadrunners are one of the very few predators of this insect.

After mating, the female Tarantula Hawk must find and subdue a tarantula, which will act as a food source for her  offspring. It may be a tarantula that is wandering above ground in search of a mate, or in some instances she may even approach the entrance of a tarantula's underground burrow and entice it to come out by triggering the webbing at the entrance.

Either way, the tarantula faces certain doom.

The female attacks the stronger and much larger tarantula, and delivers her paralyzing sting. Once the tarantula is subdued she either drags it back into its own burrow or to a hole in the ground she has previously prepared. The helpless tarantula is secured in the burrow and the Tarantula Hawk lays a single egg on the paralyzed tarantula's body. She then seals the burrow and leaves her egg to hatch. The larvae will consume the paralyzed living spider over the course of about a month, spin a cocoon, and then eventually emerge the next season as an adult wasp.

Only the female wasp hunts, and her stinger is about a quarter inch long. The wasps are usually docile and don't normally have a reason to sting humans. However its sting is rated as one of the most painful insect stings, second only to bullet ants of central and south america. Medical attention is not normally needed, although the effects can last for a few days.

"The serpent, the king, the tiger, the stinging wasp, the small child, the dog owned by other people, and the fool: these seven ought not to be awakened from sleep."

~ Chanakya, Indian economist and political strategist  (350-275 BC)

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