wasps

Golden Paper Wasps

Paper wasps (genus Polistes) are the most common wasps of the Sonoran desert. They are about one inch long and often brightly colored (see photo gallery). According to the Arizona-Sonora Desert Museum, common paper wasps include the yellow (aka golden) paper wasp, the Navajo paper wasp, which is deep chocolate brown with the end of the abdomen yellowish; and the Arizona paper wasp, which is slightly smaller and more spindle-shaped than the other two and is brownish-red with thin yellow cross bands on the abdomen.

A golden paper wasp (Polistes aurifer) has been inspecting my house recently, but so far, I have not seen any nests. This wasp drinks from my pool. It can land on and walk on the water because it does not break surface tension. These wasps are not usually aggressive except when defending a nest. The nest is built using tree bark and wood fibers mixed with saliva.

ASDM: The paper wasp is a social insect whose life cycle begins as a solitary mated queen. The queen overwinters deep in rock cracks, behind peeling tar paper, or inside enclosures. In spring the queen builds a paper nest suspended from a thin stalk in a protected rock crevice, among thick vegetation such as dead fan palm leaves, or under the overhang of a man-made structure. She constructs a small cluster of paper hexagonal cells and lays an egg in each. The queen then feeds the larvae that hatch from these eggs a diet of caterpillar ‘meat balls.’ When the first young worker wasps emerge from their pupal cells, they assume the tasks of hunting caterpillars, collecting material for making papier-mâché for nest expansion, and collecting water for cooling. The queen then ceases all work except egg laying. By late spring, the colonies have grown to contain 20 to 50 wasps; by late summer as many as 200 wasps may be present. At this time new queens and males are reared. After mating, the new queens imbibe nectar to fatten for the winter. By late fall, the queen mother and workers die, the nest is abandoned, and the next generation of queens goes into hibernation.

Most wasps are specialized hunters that track down their prey using smell and sight combined with knowledge of the habitat, activity periods, and behavior of the prey. A solitary wasp usually subdues its prey with a sting that either kills the prey or paralyzes it briefly or permanently. (Tarantulas stung by tarantula hawks can live completely paralyzed for months.) Social wasps, including paper wasps, never sting their prey. Instead, they use their powerful cutting mandibles to chew the prey into pieces to feed directly to their larvae. The venom of social wasps is used only for defense. (Read more from ASDM)

Most wasps are carnivores that feed on other insects and arthropods. A few species have become herbivores, like bees, and feed on nectar and pollen.

Although wasps are not pleasant to have around, they are beneficial because they are pollinators.

See also: Tarantula Hawks Deliver The Big Sting  

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The most dangerous venomous animals of the Southwest

Speckled-rattlesnakeThe southwestern desert has a reputation for venomous critters, but which are most dangerous? I attended a lecture at the Arizona-Sonora Desert Museum given by James W. Cornett, a biologist, author, and emeritus Curator of Natural Science at the Palm Springs Desert Museum. Cornett has studied venomous animals for over 30 years and gave us a list of what he considers the thirteen most dangerous animals.

This list is subjective and includes consideration of the toxicity of the venom, the amount of venom injected, the possibility of an allergic reaction, the abundance of the animal, and the probability you could actually encounter the animal. Here is his list from the least dangerous to most dangerous:

13. Tarantulas. The venom is generally not dangerous to humans and it takes much provocation to get a tarantula to bite you.

12. Centipedes. Some of these can get over 20 inches long (but most are about 5 inches) They deliver venom by pinching with its front legs. One death has been attributed to a centipede bite.

11. Velvet ants (actually wasps). These look fuzzy and cute but deliver a very painful bite.

10. Gila monster. These lizards are venomous but it takes much provocation to get them to bite you.

9. Coral snakes. The coral snakes in the Southwest are generally small. More deaths occur in the East where the snakes are larger.

8. Cone-nosed bugs (aka Kissing bugs). Bites from these bugs can produce an allergic reaction and can transmit Chagas Disease, a chronic and debilitating protozoan infection. Cone-nosed bugs feed on the blood of other animals, mostly rodents.

7. Ants. Swarming ants, by their large numbers can deliver painful bites and cause allergic reactions.

6. Scorpions. Most scorpion stings in the southwest are not dangerous. However, bark scorpion venom is dangerous to humans.

5. Brown (recluse) spiders. The venom is very persistent and causes tissue damage.

4. Wasps.

3. Black Widow spiders. Drop for drop, black widow venom is the most toxic of any animal in the southwest. And now, we are seeing more Brown Widow spiders coming into the area.

2. Rattlesnakes. This venom does great tissue damage and two species, the Tiger rattlesnake and Mohave rattlesnake also have neurotoxic venom. By the way, there are 18 rattlesnake species common to Arizona.

And the most dangerous venomous animal:

1. Africanized Honey Bees. According to Cornett, bees cause more deaths than all the other animals combined.

Besides these animals, Cornett mentioned some snakes that are considered only mildly venomous, some of which are commonly kept as pets. None of these snakes have fangs, but the do have enlarged back teeth and toxic saliva. They need to chew on you for a while to work the venom in. These snakes include the ring-necked snake, black-headed snake, spotted night snake, lyre snake, hog-nosed snake, and the common garter snake.

Cornett related an incident with a hog-nosed snake. This snake was in an exhibit at the Palm Springs Desert Museum. Cornett was attempting to feed it a mouse, but since he handled the mouse, its scent got on Cornett’s hand. The snake bit him on the web between thumb and forefinger and chewed for a while before it could be detached. This mild venom caused swelling and discoloration of Cornett’s hand and arm and produced blisters for about a month. Nobody has antivenom for these snakes.

For more information on venomous animals, see:

Desert Bees and Africanized Bees

Scorpions, Vinegaroons, and Sun Spiders

Tarantula Hawks Deliver The Big Sting

Venomous Centipedes and Cyanide-Oozing Millipedes

Who’s Afraid of Tarantulas?

Rattlesnakes

Venomous Lizards