# Organ pipe mud dauber (Trypoxylon politum) > A slender, black mud‑nesting wasp that builds long tubular nests and provisions each cell with spiders for its larvae. Source: https://insectscanner.com/species/organ-pipe-mud-dauber/ (updated 2026-10-10) ## Is it dangerous? **Can sting.** Organ pipe mud daubers are not aggressive and rarely sting unless directly handled or squeezed. The sting can be painful but is not considered dangerous for most people. Wash the sting site with soap and water and use a cold compress and over-the-counter pain relievers or antihistamines as needed. If someone has trouble breathing, swelling of the face or throat, dizziness or widespread hives, use an epinephrine auto-injector if one is prescribed and call emergency services. **Pets:** Generally not a threat to pets. Large dogs or cats that try to catch or swallow an adult wasp could receive a sting; small pets might be more affected if stung repeatedly. Observe for allergic reactions and consult a veterinarian if needed. ## Quick facts - Scientific name: Trypoxylon politum - Also called: Tube wasp, Mud dauber wasp - Order: Hymenoptera (Bees, wasps and ants) - Family: Crabronidae (Sand wasps and relatives) - Size: About 15-25 mm body length - Colours: Glossy black, Dark brown wings, Pale yellow legs (tips sometimes pale) - Habitat: Sheltered vertical surfaces near spider‑rich habitats: buildings, barns, bridges, rock overhangs, hollow trees and sometimes artificial nests. - Range: Eastern North America: from southern Canada through the eastern and central United States. - Active: Spring through early autumn (generally April to October in much of its range); active during warm daylight hours. - Lifespan: Adults live for a few weeks to a couple of months; full generation from egg to adult takes weeks depending on temperature. - Effect on plants: Spider predator / incidental pollinator - Pest: no ## Overview Trypoxylon politum is a solitary mud‑nesting wasp common in eastern North America. Females build long, parallel mud tubes (hence the common name "organ pipe") on sheltered vertical surfaces such as building eaves, bridge supports, and rock overhangs. Each tube is divided into several cells; the female stocks each cell with paralyzed spiders, lays a single egg, then seals it with mud. Adults are non‑social and typically unaggressive toward people. They are predators of spiders and occasional flower visitors because adults feed on nectar. Nests may persist for years and are reused or reoccupied by other insects after the original brood emerges. ## How to identify it Adults are slender, elongated wasps about 15-25 mm long with a narrow "waist". The body is glossy black and the wings are dark, sometimes with a bluish sheen; the hind feet (tarsi) are white, which is a helpful field mark. Females carry balls of mud to build nests: long, smooth, parallel mud tubes about a centimetre wide and up to about 15 cm long, grouped side-by-side like organ pipes. - Look for long parallel mud tubes attached to sheltered vertical surfaces; each tube houses multiple cells. - Adults are slender, glossy black wasps about 15-25 mm long with narrow waists and white hind feet. - Females are often seen carrying wet mud to build or repair tubes. - Cells often contain visible stacked spider bodies when opened (do not open active nests). ## Lookalikes - **Black and yellow mud dauber** (Sceliphron caementarium): Sceliphron caementarium has a yellow-and-black pattern and a very long, thin yellow waist; it builds clusters of short cells that are often plastered over into a lumpy mass, not long parallel tubes. - **Other Trypoxylon species** (Trypoxylon spp.): Other Trypoxylon are similar but often differ in subtle body proportions, local range, or nest placement; T. politum is notable for its long parallel 'organ pipe' clusters. ## Life cycle - **Egg:** A single egg is laid in a mud cell on top of the paralyzed spiders that the female provisions. - **Larva:** Larvae hatch and consume the stored spiders; this stage lasts several days to weeks depending on temperature and food. - **Pupa:** After feeding, the larva pupates within the sealed mud cell and later develops into an adult. - **Adult:** Adults emerge, mate, and females build new mud tubes and provision them with spiders. ## Diet and predators - Young eat: Paralyzed spiders provided by the female (spider specialist predator). - Adults eat: Nectar and other sugary liquids; sometimes honeydew. - Predators of the young: Parasitic wasps, flies and predators that can breach or invade mud tubes (various parasitoids and kleptoparasites). - Predators of adults: Birds, dragonflies and other insectivores. ## Effect on plants and gardens Adults feed on nectar and may visit flowers, so they can act as incidental pollinators. Their larval feeding on spiders reduces local spider numbers but does not harm plants. ## Where and when to find it Look for clusters of smooth mud tubes on eaves, porch ceilings, bridge undersides, inside barns, or under rock overhangs. Adults are active on flowers and nearby while hunting spiders. - Best time: Spring through early autumn (April to October in much of its range); midday to afternoon when temperatures are warm. - Tips: Photograph nests from a distance to avoid disturbing wasps. Watch females carry wet mud or prey—these behaviors make identification easy. ## Fun facts - The common name "organ pipe" comes from the neat bundles of mud tubes that resemble the pipes of a church organ. - Females are spider specialists: each larva is fed only spiders, which the female paralyzes with her sting. - Unusually for wasps, the male often stays in the nest tube to guard it while the female collects mud and spiders. ## Frequently asked questions ### Are organ pipe mud daubers dangerous? Only mildly. They are solitary and rarely sting unless handled or trapped; stings are painful but not typically life-threatening for people who are not allergic. ### Do organ pipe mud daubers sting people? Yes, females can sting but they rarely do so. Most people will not be stung unless they try to touch, crush, or trap the wasp. ### Why is an organ pipe mud dauber building nests on my house? They seek sheltered vertical surfaces protected from rain and wind, such as eaves, porch ceilings, garages and sheds. These sites are convenient for attaching mud tubes and are near spider prey. ### How do I get rid of organ pipe mud daubers? Removal is usually unnecessary because they are beneficial. If nests are unwanted, remove them in late winter when inactive, or discourage nesting by sealing gaps, reducing sheltered ledges, or applying a rough surface or wire mesh. Do not attempt nest removal while adults are active without protective clothing. ### Will organ pipe mud dauber nests damage my home? Nests are made of mud and do not structurally damage buildings, though repeated nesting can leave cosmetic stains. Mud can be easily brushed away and painted over if needed. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/84844), [Wikipedia](https://en.wikipedia.org/wiki/Organ_pipe_mud_dauber). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.