Mud wasps are not usually dangerous. The wasp that sticks lumps of dried mud under your eaves works alone and has no colony to defend. The Australian Museum's mud-dauber page says the sting can be painful but attacks are rare. The nest is still worth a proper look, because mud on a house can also mean termites, and a nest near a door or in a home with a sting allergy is a reason to book a technician.
What are mud wasps?
"Mud wasp" covers more than one insect. The Western Australian Museum's fact sheet on slender mud-daubers says mud nests are built by a wide variety of wasps in the families Vespidae, Sphecidae and Pompilidae. Two groups turn up on Sydney houses.
Mud-daubers, mainly Sceliphron laetum, are one of the more commonly encountered wasps in Sydney, according to the Australian Museum. The WA Museum describes them as 17 to 26 mm long, mostly black with yellow markings, and easy to recognise by an extraordinarily thin, straight, stalk-like first segment of the abdomen.
Potter wasps are smaller, about 1.5 cm, and belong to the same family as paper wasps. Unlike paper wasps, they do not form colonies. A related mud builder called Delta also has a stalked waist, but the WA Museum says it is not straight, the wings sit in a V when it settles, and it is orange and black.
Why are they building on my house?
The Australian Museum says adult mud-daubers collect water and mud and build nests in protected parts of houses, buildings and rock overhangs. Each female builds and stocks her own nest. She seals several paralysed spiders into it with one egg, and the grub eats them after it hatches.
So a mud nest is a nursery with its own food supply. Potter wasps stock theirs with caterpillars, and the Australian Museum adds that they sometimes use an abandoned burrow made by another insect instead of building one.
Kurnell has Botany Bay National Park on its eastern side and Towra Point Nature Reserve on its western side. A Kurnell owner who finds a row of grey mud lumps along a garage eave, with wasps arriving carrying something in their jaws, should book wasp nest removal in Kurnell so the nest is identified and cleared safely.
How do you tell a mud nest from other nests?
Paper wasps chew wood fibre into open, papery cells that hang from a ledge, while mud wasps build with mud. The WA Museum describes how two mud-dauber species differ:
- Sceliphron laetum packs its cells together into one large mass, and the finished nest is covered in rough ridges of mud.
- Sceliphron formosum builds separate cells that taper to a blind end and close with a flat cap at the opening.
Potter wasp nests can look different again, so take a photo from a distance and don't pick at the nest to check inside.
Is it a mud nest or termite tubes?
This is the mix-up that matters. The NSW Government's heritage sheet on wood preservation says subterranean termites build shelter tubes of mud that can run up the side of a pier or stump, or over the base of a masonry wall, to the timber floor above. It also says the first sign of activity is often the collapse of floorboards.
A wasp nest is a lump of cells built by an adult carrying mud to one spot. A termite tube is a covered track that joins the ground to timber. Mud near the base of a wall, on a subfloor pier or running up toward timber is more likely termite work than a wasp nest.
A Woronora home with dried mud running up a brick pier under the floor needs termite inspection and treatment in Woronora before anyone assumes it is a wasp. Leave the mud untouched until the technician has seen it.
How bad is the sting?
The Australian Museum says potter wasps can deliver painful stings but are not aggressive and rarely attack people. The WA Museum says mud-dauber females sting if handled.
healthdirect says wasps rarely leave a sting in the skin. For a simple sting, wash the area with soap and water, apply a cold pack wrapped in a cloth and take pain relief if needed.
Get urgent medical help if the sting is in the mouth, throat or near the eyes, if there is more than one sting, if you feel dizzy or have tummy pain and vomiting, if a large area turns red and swollen, or if you have had anaphylaxis to a sting before. healthdirect says allergies to stings are one of the most common causes of anaphylaxis in Australia. For anaphylaxis, use an adrenaline autoinjector if you have one, then call triple zero (000).
When should you book removal?
healthdirect's advice is to leave insect nests alone and have ant, bee and wasp nests removed by professionals. Mud wasps are the mildest case, but these still call for a technician:
- the nest is beside a door, letterbox, clothesline or play area
- it sits in a window track, meter box or gap where you can't see how large it is
- someone in the house is allergic to stings
- you can't be sure it is a mud nest and not a paper wasp or European wasp site
A technician identifies the wasp, checks for other nests nearby and removes the nest. Knocking it off with a broom or hose scatters the wasps and puts you within reach of a sting. A Loftus family with fresh mud lumps over the back door can arrange urgent wasp and bee removal in Loftus before the nest gets bigger.
A Yowie Bay home with mud nests packed into the track of a sliding window can't be cleaned safely by hand, so quick wasp nest removal in Yowie Bay is the sensible call.
Before you book
Note these details so the technician knows what to look for:
- where the nest is, and how high it sits
- what it is made of: hard grey or brown mud, grey paper or wax
- whether it looks like a single lump, separate tapered cells or a long covered track
- how many wasps you see, and what they are carrying
- whether anyone at home is allergic to stings
Send those details when you contact us for wasp and bee removal across the Sutherland Shire: call Sutherland Shire Pest Control Pro on 02 8360 3033 or email [email protected].