This past week two scary looking insects appeared on my desk, just in time for Halloween.
The first insect to make the appearance was a true bug belonging to the heteropteran family Reduviidae, known as an Assassin Bug. The family includes over 190 species in North America, and they are all meat-eaters. The common name for the family clearly describes how these predatory, stealthy hunters make a living.
Family members sport two features that support their predatory lifestyle. They have raptorial front legs designed for grabbing and holding prey. Their piercing-sucking proboscis looks like a beak. It swings into action (literally) to inject paralyzing and pre-digestive enzymes into prey which is most often another insect. They then suck the essence-of-insect from their hapless victims.
Assassin bugs develop from eggs to adults through incomplete metamorphosis. I have never liked this term because it sounds like something horrible gone wrong during development – like only popping out legs on one side of their bodies, so they run around in circles (just kidding). It means they pass through three developmental stages: eggs, nymphs, and adults. This is in contrast with insects such as butterflies that develop from eggs to adults through complete metamorphosis where a complete change occurs during the pupal stage.
The adult assassin bug that appeared on my desk was a Wheel Bug. Thankfully it was encased in a used water bottle. This true bug gets its name from a peculiar feature that rises from the top of the bug’s thorax. The structure looks like half of a cogwheel, with the gear teeth clearly visible. Wheel bugs are big, measuring over 1 1/4-inches long, and their color varies from light gray to bluish gray to grayish brown.
Caterpillars, in the order Lepidoptera and sawfly larvae in the order Hymenoptera, are favored table fare of these voracious predators; however, they will not turn their beaks up at other arthropod meat morsels. Indeed, they will even nail the probing fingers of uniformed gardeners.
While these are beneficial insects, they should not be handled. All members of the family can deliver a painful bite to people. The pain of a bug bite has been described as equal to or more powerful than a hornet sting, and the wound may take over a week to heal.
The second insect to appear on the scene was an adult of the American Oil Beetle (Meloe americanus). The American Oil Beetle is also a predator; however, it may not be a beneficial insect. Quite honestly, in my career as a horticulturist this is the first time, I have seen this insect.They are quite rare in Northern Ohio and are found on sandy soils. The larvae feed and become parasites of native ground nesting bees, digger bees and solitary bees, while the adults feed on the foliage of flowers.
If feeding on native bees is not scary enough, the adults, if handled, cause skin blisters by emitting a chemical called cantharidin that creates blisters. These wounds will heal, but they are painful. The adults are relatively soft-bodied, dark insects ranging from a half-inch to 1.25 inches in length. The visible part of their thorax is narrower than the head and the abdomen. The front wings only cover a small portion of the abdomen.
Finally, another critter to be on the watch for is the Wolf spider. Spiders are not classified as insects, rather as Arachnids because they have eight legs compared to insects that have six legs. The Wolf spider does not spin webs, yet it is one of the most common outdoor ground spiders encountered. This relatively large hairy spider is about the size of a half dollar coin. Though it rarely bites humans, unless handled, it can inject venom that is painful. These spiders are quite shy and can be accidental intruders in homes. During autumn, cooling temperatures prompt them to seek cover and find mates, which ultimately leads them to discover cracks and holes in homes. A common entry point for the spider is under doors.
The best defense against spiders invading the home is to prevent them from entering in the first place. Replace worn-out exterior door sweeps, including doors leading into attached garages. Also remember to caulk around window frames.