Amazing Assassins

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Published on: Jun. 2, 2003

Last revision: Nov. 15, 2010

and their gender becomes evident. Females are larger and have wider bodies than males.

Some of Missouri's assassins pass the winter as adults rather than eggs. Pselliopus barberi is a half-inch insect colored Halloween orange with black speckles. It hibernates under rocks or bark or in logs, sometimes in large groups. It turns up on foliage and flowers in the spring and fall.

Stop to smell the flowers, and you may come nose-to-nose with the spined assassin bug, Sinea diadema. Fortunately, people are not on its menu. It is a valuable predator of several kinds of plant-eating insects. Spined assassin bugs produce two generations per year and are common on goldenrod in the fall. Their brown color, rugged body shape and spiny legs let them pass for bits of dried-up leaves.

An even more convincing disguise is that of ambush bugs. Phymata fasciata and P. vicina are practically animated blossoms. At only one quarter of an inch, with squat bodies and cream, yellow or pale-green color, they blend seamlessly with wildflowers in all stages of budding and blooming. Even during courtship and mating, when the males ride piggyback atop females, their camouflage remains uncompromised.

Until recently, ambush bugs were placed in their own family, the Phymatidae, due in part to their unusual, vise-like forelegs that they use for grabbing prey. They routinely tackle butterflies, large wasps and flies, but sometimes they get greedy. I once saw one seize a hovering bee, only to be yanked off its perch when the bee retreated.

Young bee assassins, Apiomerus crassipes, are also ambush hunters, but the large, robust adults pursue prey from flower to flower. Black with red trim, they advertise their own distastefulness to predators. Sticky hairs on their front legs help them secure struggling prey. Look for them in open woodlands in June and July.

Our two species in the genus Zelus also have tacky legs. They are slender and lanky, pale green or brown, and more common on foliage than flowers. The males of at least one Colombian species guard their eggs against parasites, but our domestic varieties don't exhibit this behavior. Both sexes are beneficial predators of crop and garden pests.

Perhaps the most bizarre assassins are the thread-legged bugs. There are at least four Missouri species. All are extraordinarily thin, with stilt-like walking legs and front legs similar to those of a mantis. Most are only one half

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