As with several wasps, Pachodynerus erynnis does not have a widely accepted common name although Red and Black Mason Wasp and Red-marked Pachodynerus are used as common names—our preference is the former as it is more descriptive of the insect in addition to “rolling off the tongue” a bit easier than the latter name! Mason wasp is another name sometimes used but it a more generalized term which also describes several closely related wasp species.
The Red and Black Mason Wasp can be found throughout Galveston-Houston area. It is a valuable insect predator despite the fact that most gardeners are not likely to know its name or its beneficial value. The population of Red and Black Mason Wasps has been increasing over the last few years; these wasps were remarkably abundant during 2007. During a mild day in mid-December 2007, we counted 14 Red and Black Mason Wasps visiting flowers of an ornamental amaranth growing in our Master gardener Demonstration Garden.
Like its close cousin the Potter Wasp (Eumenes fraternus), the Red and Black Mason Wasp can also be found across the United States, especially in temperate climates. Pachodynerus erynnis is the only red-marked species of Pachodynerus to occur in the United States. While males and females have similar coloring, males have a white to slightly yellowish-colored and pentagonal (five-sided) spot on their face. Females have a reddish coloration in the same area of heads. Adults will feed on the nectar of flowers, thus helping pollination (of special benefit lately with the decline in bee populations).
Females begin construction of nests after mating. Also like the Potter Wasp, the Red and Black Mason Wasp constructs its brood-rearing nest from dry soil which is then mixed with saliva to a mud consistency. However, the nest of the Red and Black Mason Wasp is much more utilitarian in appearance—consider it the modernist architecture of the Vespidae or wasp family.
Curiously, Red and Black Mason Wasps will sometimes tunnel through the mortar between bricks to provide shelter for its developing young. Even more surprising is the fact that Pachodynerus erynnis commonly utilize and “refurbish” old mud dauber nests as brood nests to rear their young—a novel form of recycling. Female Red and Black Mason Wasps will also create brood nests in hollow stems (we have observed nests in stems of angel’s trumpets ).
After nearing completion of a brood nest, the female wasp will collect several hairless or near-hairless caterpillars and beetle larvae, which she paralyzes with her stings. She provisions the interior of each brood cell with the paralyzed caterpillars. She then lays an egg on one of the paralyzed caterpillars and the immature stage feed on the caterpillars.
Noctuidae caterpillars are typical prey of the Red and Black Mason Wasp; when you stop to consider that Noctuidae caterpillars include cutworms, cabbage loopers, armyworms and corn earworms, it’s easy to understand why the Red and Black Mason Wasp is a beneficial in the garden!
Pachodynerus erynnis is a solitary wasp, which means that it does not form colonies like yellow-jackets or hornets or paper wasps. Red and Black Mason Wasps do not defend their nests and are not aggressive—in fact, they only pose a threat if mishandled or pinched.
On a final, technical and artistic note: because the nests of the Potter Wasp and the Red and Black Mason Wasp are made up in large part of local clays, they do in fact stand up in a 2000 degree Fahrenheit kiln! However, because they have little flux material in them, they are not fully fused and are quite brittle.
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