After reading a New York Times article with the sub-title “A beekeeper in Savannah, Ga., found what turned out to be a yellow-legged hornet. State and federal officials, along with academic experts, are working to eradicate the species” I spotted this wasp foraging our flowers in Ithaca, New York. Its yellow legs caught my eye, although the apparent size (seemed larger in article photograph) and face and body markings seemed different. Using an Apple Iphone 14 ProMax I captured three macros from different angles, I attached them to an email to the local Cooperative Extension office. They gave me a quick response, confirming my suspicion this was a different “yellow-legged wasp.” The agent suggested it might be a “paper wasp” and directed me to a Cornell site were, for a $25 fee, an identification could be made.

Instead, this morning I found “insectidentification.org” with an excellent search capability. Under “Bee, Ant, Wasp and Similar insects that can be found in the state/territory of New York,” the third row from top spotted an exact match being the only Yellow-legged native wasp. I am going to respond to the agent with this identification as others in the area may have the same question, given the name of the invasive wasp.

“It is the Yellow-legged Mud-dauber Wasp (Sceliphron caementarium), also known as Black and Yellow Mud Dauber, Black-waisted Mud-dauber. Of the Latin species name, Sceliphron caementarium, caementarius means mason or builder of walls.”

“These are solitary parasitoid wasps and build nests made of mud. The family of sphecid wasps collect mud balls at puddle and pool edges for constructing nests comprised of up to 25 vertically arranged, individual cylindrical cells. Frequently, nests are built in shaded areas inside formations that are sheltered from the weather or from other environmental elements. These sites may be naturally-occurring, or man-made structures. Some examples are: under and inside various types of bridges, barns, garages, open-air porches, or under housing eaves. A female might take only a day to construct a cell requiring dozens of trips carrying mud. Females will add new cells one by one to the nest after each cell is provisioned. They provision these nests with spiders, such as crab spiders, orb-weaver spiders and jumping spiders in particular, as food for the developing larvae. Each mud cell contains one egg and is provided with several prey items. The wasp then seals the cell with a thick mud plug. After initial creation and covering of the clutch, this sphecid wasp uses more mud as a means covering and protecting the whole cluster of cells, thereby forming a smooth appearance, and a uniform nest. The entire nest may attain an area equal to, or larger than, the size of an average human fist.”

“After finishing a series of cells, she leaves and does not return. While consuming the prey and increasing in size, the larva molts several times, until it molts into a pupa. Once the pupa has developed into an adult wasp, the adult emerges from its pupal case and breaks out of its mud chamber.”

“Various parasites attack these nests, including several species of cuckoo wasps, primarily by sneaking into the nest while the resident mud dauber is out foraging.”

“Adults can be seen in mid-summer feeding on nectar at flowers, especially Queen Anne’s lace (Daucus carota), parsnips and water parsnips (Sium suave, Sium latifolium, Berula erecta). They have a low reproductive rate. Stings are rare due to their solitary and usually nonaggressive nature; however, nests are aggressively defended.“

“Like other solitary wasps, Sceliphron species are not aggressive unless threatened. They are sometimes regarded as beneficial due to their control of spider populations, though the spiders themselves may be beneficial in controlling pest insects.”

“This species is found in a wide variety of habitats, such as rock ledges, man-made structures, puddles and other water edges, cypress domes, in long leaf pines (Pinus palustris), and in turkey oaks.“

“S. caementarium is widespread in Canada, the United States, Central America and the West Indies, and has been introduced to many Pacific Islands (including Australia, Hawaii, and Japan), Peru and Europe, where it has become established in some countries of the Mediterranean Basin (Croatia, France and Corsica, Italy, Cyprus,Malta, the Canary Islands, and Madeira) and Austria, and Ukraine.“

“Sceliphron caementarium can reach a length of 24–28 mm (15⁄16–1+3⁄32 in). Their petiole is generally black and is about half the length of the entire abdomen, however the population in the desert southwest often has a yellow petiole. The thorax shows various yellow markings, while the abdomen is normally black, with yellow propodeum (typical of females). The eyes are black, the antennae are black, and the legs are yellow with black trochanters and femurs. Within the United States, it is the only species with yellow-marked legs. The wings are a tawny color.”

“In 1996, Birgenair Flight 301 crashed near Puerto Rico. The most probable cause of this Boeing 757 crash was a blockage in a pitot tube by a mud dauber’s nest.”

Around our home these mud-daubers favor hollows within our aluminum fencing.

Reference: text in italics and quotes paraphrased from Wikipedia “Sceliphron caementarium” and “Sceliphron.”

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