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HYMENOPTERA, Sphecidae (Ampulicinae) (Sphecoidea) -- <Images> & <Juveniles>

Description & Statistics

The subfamily Ampulicinae contains species that seldom dig burrows, but rather utilize natural cavities for nests, which are provisioned with immature cockroaches. Williams (1919b) described the behavior of Dolichurus stantoni Ashm., which attacks nymphs of several genera of cockroaches. The agile cockroaches are located by the female who grasps one by a cercus or leg, and then stings it in the throat or thorax. As only partial paralysis ensues, the cockroach is able to continue slow movement. Then the wasp grasps an antenna near the base and leads or drags the prey to the nest (Clausen 1940/1962). The female positions the prey in the nest, and lays an egg rather obliquely on one of the middle coxae. After hatching in 1-2 days, the larval feeding period is completed in 4-5 days. D. stantoni as introduced to Hawaii from the Philippines in 1917 and became well established.

Similar behavior is displayed by Ampulex caniculatus Say, which attacks Poreoblatta virginica Bam. (Williams 1929). In this case paralysis is complete and the female then bites off the distal 3/4ths of the antennae, feeding on the exuding body fluids. She then transports the prey to the next where the cockroach quickly recovers to some extent from the sting. The egg is then laid on the coxa of one of the middle legs. No other species in this subfamily is known to amputate the prey's antennae (Clausen 1940/1962).

Another interesting case of parasitism is described by Hingston (1925). Ampulex assimilis Kohl attacks the cockroach, Shelfordella tartara Sauss. in India. Only female hosts are attacked probably because they are wingless and cannot readily escape. Paralysis is not complete, but the sting quiets the cockroach so that it can be led to the burrow, which is usually that of a beetle in a palm tree. A suitable storage site is found and the egg is fastened to the femur of one of the legs. Initial feeding occurs at a puncture in the femur, and the partly grown larva enters the cockroach body, feeding for some time as an internal parasitoid. The thoracic tissues are consumed first. The body contents, but not integument, are consumed and the cocoon is spun within the host's abdomen.

The tarsal claws were toothed or cleft along the inner margin (Finnamore & Michener 1993) . The mesotibia has 2 apical spurs, and the hind wing either has a small jugal lobe or it is absent. There is a sessile metasoma or the petiole is composed of the tergum and sternum.

They are mainly tropical with more than 172 species known as of 2000. Finnamore & Michener (1993) reported 2 subfamilies: Ampulicinae and Dolichurinae. They are considered to be the most primitive of the Spheciformes. Adults of tropical species are usually metallic green and may reach 33.5 mm in length. They prey on Blattoidea (Dictuoptera). Females paralyze their prey, and transport it to a cavity where an egg is laid.

References: Please refer to <BIOLOGY.REF>, [Additional references may be found at: MELVYL Library]