Length: 8-11 mm
Richman and Whitcomb (1978) reared Stiretrus anchorago in the laboratory under two different temperature regimens. The eggs developed quickly, hatching after 5-8 days. Total development time from oviposition to adult was also rapid, taking 32½ to 35½ days.
Richman and Whitcomb noted without comment that the male:female sex ratio of the hatchlings was 2:1 when the temperature was a constant 27° C., but was 7:8 when temperature varied between 18-30° C.
Richman and Whitcomb's article describes the mating of Stiretrus anchorago this way: "The male mounts over the head or rear of the female and then maneuvers so that he can take up the characteristic end-to-end copulation position of Hemiptera. The male buzzes his wings every few seconds during mounting."
This colorful stink bug is an economically beneficial species, eating a number of agricultural pests including Sulphur caterpillars, Mexican Bean Beetle larvae, Soybean Loopers, and Colorado Potato Beetles.
Waddill and Shepard (1974) told how to differentiate the sexes: the females are considerably larger, weighing in at 74 milligrams, while the males weighed a mere 47 mg. Also males possess "depressed pubescent patches on either side of sternal segments 4-6."
Mori and Wu (1991) reported that male Stiretrus anchorago produce an aggregation pheromone.
Cornell University's Thomas and Maria Eisner in 2000 studied a tortoise beetle species whose larvae construct a shield of feces to use in defense against predators. This fecal shield is mounted on a fork-shaped structure, so that it can be raised and lowered and turned in different directions. To test the effectiveness of the fecal shields, the Eisners collected two generalist predators, ladybird beetle nymphs and the nymphs of Stiretrus anchorago.
The Stiretrus anchorago nymphs each were put into a petri dish with two normal tortoise beetle larvae, and two tortoise beetle larvae with the fecal shield removed. Repeating the experiment with a total of four last-instar Stiretrus anchorago and sixteen tortoise beetle larvae, the Eisners found that the Stiretrus nymphs ate all of the artificially denuded tortoise beetle larvae but made no effort to eat any of the tortoise beetle larvae with the fecal shield intact. The ladybird larvae behaved in the same way in their version of the experiment. The Eisners did find one adult Ground Beetle, however, that had no qualms about attacking the shield and eating the larvae.
Thus while Stiretrus anchorago is a generalist feeder of catholic tastes, it does have its limits, and putting its mouthparts into fecal material seems to be one of these.
Eger and Ables (1981) reported that Stiretrus anchorago is a host for the development of a Tachinid fly, Cylindromyia fumipennis.
Countries with records of Stiretrus anchorago:
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