Barbara’s got bugs.

Spiders, flies, ants and beetles share time and space with Barbara Hoffman of West Tisbury. All of them enjoy relaxing on her deck and she eagerly photographs her companions and sends me reports of the more interesting varieties. The most curious creature seen lately may be the blue wasps that she’s been watching.

Chalybion californicum, better known as the blue mud dauber wasp, is a striking, metallic blue insect with a waist that would make Jessica Rabbit suck in her breath. This wasp is one of three species of mud daubers found in Massachusetts.

Mud daubers are named for their habit of collecting mud and using it to make structures for their offspring. You see their handiwork in many places, often where you don’t want it, such as the side of your house or on other human-made structures and implements. Howard Ensign Evans, an American entomologist and wasp specialist, witnessed their penchant for placing these structures on outhouses, noting, “the passing of the outdoor privy was a sad day” for these wasps.

The mud cells are nests or brooding chambers that will safeguard and nurture the next generation of mud daubers. The blue mud dauber differs from the other two native species in that it doesn’t construct its nursery from scratch. Instead, it repurposes the nests of the black and yellow mud dauber by bringing water to soften the mud and allow for the reformation of the structure to better accommodate its own offspring. Very clever recycling. Sometimes it uses existing empty nests but, at other times, it will remove the other mud dauber’s larvae and replace them with its own.

The plot, along with the mud, thickens. After the mud nest is ready, the female wasp has more work to do to prepare it for her young. She must first fill the pantry, so to speak, in order for her larvae to have nourishment. To do this, the mud dauber goes out hunting for a protein-rich food.

Spiders are what the larva mud daubers have a taste for and their favorite are black widows. So, thank these wasps for keeping the population of these reviled spiders to a minimum in places where they are more common than the Island. The female wasp will collect spiders of this and other varieties with a clever ruse. They catch them in the spider’s own web by plucking it like a violin string, to trick the spider into thinking that there is stuck prey; when the spider reflexively comes to collect its quarry, the dauber injects its toxin into the spider and carries off the paralyzed spider to be placed in the nesting chamber.

Twenty or 30 paralyzed spiders will be in each brooding cell, after which one mud dauber egg will be laid and the chamber closed off by the mother. When the egg hatches, the larva has fresh meat, as the spiders are paralyzed but not dead, so have not decomposed. Break open a mud dauber nest and you might see the larva and its spider feast. Blue mud dauber larvae eat to their heart’s content, then spin a cocoon in which to overwinter, emerging from their mud house as adults the next spring.

As adults, these wasps go vegetarian, forgoing meat and consuming nectar, pollen or insect honeydew. They are important pollinators for Queen Anne’s lace and other wildflowers.

Though non-aggressive (and rarely stinging), these wasps might be best appreciated for their creativity and pest control: each blue mud dauber builds up to 20 cells, leading to the consumption and demise of about 500 spiders (likely to the appreciation of arachnophobes everywhere).

This fact perhaps best answers poet Dylan Thomas’ question in A Child’s Christmas in Wales: the main character considered the “usefulness” of presents he received, and lamented that he had “books that told me everything about the wasp, except why.”

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown, and author of Martha’s Vineyard: A Field Guide to Island Nature and The Nature of Martha’s Vineyard.