Phenology Memory: The Daubers

I started writing this one in June 2018, when it wasn't sponsored and posted. I’m posting it now because what I observed may still interest anyone dealing with other members of the mostly solitary wasp family called mud daubers. They are native to North America and become active whenever the weather is not really cold.

In the spring of 2018, to my dismay, the Polistes fuscatus colony who've lived with me for years suddenly collapsed. Young wasps hatched by the dozens—and then they all flew away, probably because the Brown Marmorated Stinkbug has moved in. These large aggressive bugs don’t attack humans, but they suck wasps’ eggs. Whether the native wasps realized that the imported stinkbugs were a threat to their reproductive success, or merely hate the sweetish odor of stinkbugs, who can say? (Giving the devil its due, stinkbugs eat several kinds of small nuisance insects when they can get them—but they don’t fly well enough to have a chance to catch gnats, flies, or mosquitoes, which paper wasps kill very efficiently. I sorely miss my paper wasps.)

So then a mud-dauber moved into the office room.

Mud-daubers generally are undergoing scientific review, so although the wasps are common, not much species-specific information is available as what's been published is reconsidered; species names have changed, subtle identifying details have been used to classify individuals by species. I don't know. I've always assumed that what we had were all one species, and the Wikipedia post for Trypoxylon politum, especially the "organ pipe" arrangement of their nests, seemed to match what I'd observed in past years, as here: 

https://priscillaking.blogspot.com/2017/08/phenology-tortie-tuesday-hurricane.html

(Though "5mm" has to be either a typo, or a description of the males only, if we're talking about the same animals. All the female mud-daubers I know are about 25mm, or one inch, from head to tail.)

However, according to the flashier "scientific" web pages like https://www.discoverlife.org/mp/20q?guide=Sphecidae , what came to live with me were not Trypoxylon; they were Chalybion, probably Chalybion californicum, which (despite its name) is found all across North America. They had to be Chalybion because they reflected a deep, bright, metallic blue under strong light. The wings, like some birds' feathers, reflect blue in some light and dark drab in other light. 

Photo by Jason D. Roberts at discoverlife.org : page URL https://www.discoverlife.org/mp/20q?guide=Sphecidae ; image URL https://www.discoverlife.org/IM/I_SD/0067/mx/Chalybion_californicum,_side,I_SD6774.jpg

Sam Droege had permission to use Jason D. Roberts' photo of a living Chalybion californicum queen at the site where I found it, but could not automatically share that permission. So, in case JDR objected to the pretty picture above, I pasted in SD's less flattering, closer-up photo of a dead specimen. In real life I've never been able to see the tiny hairs that even mud-daubers have; in motion they look slick and glossy, and I've not handled a dead one, which is one reason why it's hard for me to use the "scientific" sites that rely on the information you get by examining dead or frozen animals.  On consideration, since both photographers were so nice about it, why not keep both links? The full-size photo is on Wikipedia, By Sam Droege from Beltsville, USA - Chalybion californicum, F, side, MD, PG County_2013-08-08-14.01.04 ZS PMaxUploaded by tm, Public Domain, https://commons.wikimedia.org/w/index.php?curid=27833800 , or on Flickr https://www.flickr.com/photos/usgsbiml/9557305454/in/photolist-fyxFWw . 

Sam Droege's e-mail signed off with a tagline that's also worth sharing:

How Can you Save the Bees if You Don't Even Know Their Names?

Mud-daubers can be distinguished from paper wasps, before they build different types of nests, by their longer “waists.” Their tail segments hang by threads. Chalybion flash iridescent cobalt-blue under fluorescent light; much gaudier than the modest little Polistes fuscatus. Adult female sizes range from a little less to a little more than one inch from head to tail.

My perception of them has hitherto been that, as a species, mud-daubers are less lovable than fuscatus. To be fair, mud-dauber queens almost never attack. (In both species, queens’ tail ends have pointy bits they can use to stab enemies, but no venom,) Mud-daubers do, however, take many days to learn to recognize and trust you, the way a paper wasp queen learns to do in minutes (and the workers, who are full of venom, then take their cue from their queen). For all practical purposes they don’t bond with humans, because humans, even serious Green humans like this writer, get tired of their constant challenges. Eventually the mud-daubers I’d known challenged me when I was near a fire, and I swatted them into it.

Last year, feeling that any queen wasp was better than none, I allowed one mud-dauber queen at a time to stay in the office room. To my surprise, I did not have to put up with constant challenges. Each learned to recognize me, and both queens became such congenial office mates that I even gave them names: in the spring I called my office companion Cobalt, and in the fall I called her heir, presumably a daughter or granddaughter, Shimmer.

Cobalt basically seemed to learn to recognize me in one day; we got on well. Shimmer made threat displays with decreasing frequency over the first three days, then settled in as peacefully as a paper wasp.

I have no scientific explanation for this. Wasps have highly developed senses of smell and taste; probably they react to the scents of rival wasps in the environment. Possibly other mud-daubers weren’t able to calm down and accept humans because being in paper wasps’ territory made them nervous. Possibly Chalybion are less wary than Trypoxylon. Mud-daubers, like paper wasps, are equipped with a very elaborate set of survival instincts that produce an illusion of intelligence, astonishing in an animal of their size. Actually they’re slow learners with little problem-solving intelligence. I was surprised and pleased to see that they did learn, albeit slowly.

They did not, of course, learn their names; giving them names was purely a whim of mine, because each behaved differently from others that presumably belonged to the same species, even the same local family. Wasps’ perceptions are very acute but probably alien to ours. They probably hear a lot of things humans don’t hear; but they probably don’t hear most ordinary human speech. They definitely recognize human moods, probably by a combination of sight and scent. They probably can hear the louder, shriller pitches of humans shouting angrily; they recognize those sounds as different from children’s squeaking or happier humans’ singing. 

Wasps don’t like people who are tense, angry, or nervous. They accept and may even defend people who are calm. Wasps will chase people who panic and run away; it’s probably unfair to suggest that they are bullies, probably closer to the truth to imagine that they perceive all tense behavior as a potential threat and respond with their own threat displays. (The ones who chase people are mostly queens, and for these species their threat display is mostly bluff. They can jab, nip, and scratch, but not really sting.) If you want to work in the vicinity of a wasp’s nest, mellow out and move slowly.

Each little queen flew around the office once or twice a day. If I were inside and could look, I could usually see the gnat or mosquito she was pursuing. They did most of their hunting and nest building outdoors, going in and out through a crack between window panes. On wet days they sheltered in a crevice in the window sill. (Mud-daubers daub mud on walls, trees, etc., to build little houses for their eggs to hatch in; they don’t live in these houses, themselves.) Both Cobalt and Shimmer brought their mates indoors too.

The social wasps, like paper wasps, can fairly be said to have three sexes; male, female, and “workers” have different body shapes and social roles. Unlike a bee colony, which has one queen and hundreds of workers, a paper wasp colony can have multiple queens and no workers. Also unlike a bee colony, where the workers can sting once in their lifetimes but the queen can sting repeatedly, in a paper wasp colony only the workers have venomous stings. Male and female parts have sharp points the wasps use to stab attackers at the same time they scratch and bite in self-defense, producing a sensation humans find unpleasant, but harmless. Mud-daubers don’t form colonies; some sources suggest that they may have workers, but I’ve not seen any.

That may be due to lack of careful observation. Worker wasps are almost as big as queens. It can be hard to tell which is which without seeing them together. What I know for sure is that neither Cobalt nor Shimmer brought in a daughter, but each brought in a mate--I think Shimmer had two.

Male wasps are tiny. Without looking them up, anyone would think they were a separate species. Females can and do carry the males around, sometimes while mating, as easily as a woman carries a baby. My office-mates brought their mates into the office room. I’m not sure exactly where the male mud-daubers spent most of their time or what they did, apart from catching an occasional gnat and, from my perspective, impersonating malnourished houseflies. I suspect the females shared food with them. Certainly they encouraged the little fellows to stay in the office, that nice safe dry place they had found.

Several times I thought the male wasps were flies, but before swatting them I noticed that their tiny tail ends hung by threads, and their antennae, almost as long as their mates’, looked absurdly out of proportion to their heads, so I left them alone. Their whole bodies were about as long as their mates’ tail segments, and thinner. They didn’t look as if they were built to last even eight weeks, but Cobalt’s mate lived with us for at least five weeks. Wary at first, as most males are, he seemed to become familiar with me as something that attracted prey species for him to chase.

It didn’t pay off. Eventually I felt something like a mosquito landing on my shoulder, swatted, and—whether or not I’d also killed a gnat or mosquito—realized I’d killed Cobalt’s mate. Whether she was tired of him anyway, realized it had all been a misunderstanding, lacked the instinct to investigate a fellow Hymenopteran's death, or had the instinct to investigate only in the case of more valuable females, she did not go into the sort of investigation and threat routine I’ve seen mud-daubers do when a paper wasp or carpenter bee was killed. She was growing old, for a wasp, and did not bring in another mate.

Shimmer, however, kept one male mud-dauber in the office for about two weeks. He was small enough to fly through the crack between windowpanes. When I stopped seeing him, I guessed that he’d been eaten by a bird. Then again, Shimmer seemed to spend less time in the office after he disappeared; possibly he’d found a place to stay outdoors. In any case, after a few more weeks Shimmer brought a male mud-dauber into the office again. He didn’t seem to know his way around, even in the witless way mud-daubers know what little information their microscopic minds store. Either the original male completely forgot his former home, or Shimmer lost one mate, lived alone for about a month,. and found another mate.

I think it’s possible that the little male wasps, whom I often saw on the floor, were eating the microscopic larvae of the previous summer’s cat fleas. Certainly the cats had been bothered by fleas, and certainly, even after Traveller moved in with that stinky flea collar merely motivating the fleas to cluster on his back end, the office remained flea-free. There are no house plants in the office room, so if the wasps ate plant sap or nectar, they went in and out to get it. There were plenty of spiders, gnats, tiger mosquitoes, and the occasional fly for these mostly carnivorous wasps to eat.

Mud-daubers are usually perceived as solitary animals, dying of old age before their eggs hatch, and they don’t usually seem clever enough to have much of a social life. I now wonder, though, to what extent they experience themselves as couples.

As companion insects I found them very inferior to Polistes fuscatus, the species nature seems to have destined for dominance in my part of the world. Polistes fuscatus eat a wide range of nuisance insects, from gnats to human-toxic hairy caterpillars, and control nuisance insect populations with incredible efficiency. Paper wasps build their nests out of the chewed-up solid parts of nuisance insects, so they kill more than they actually eat, and live in large colonies of avid nuisance-insect eaters. Mud-daubers spend a lot of their time literally mucking about beside streams and puddles, selecting just the right mix of mud and sand for their cement works. However, people who live in fear of being stung by other wasps might like daubers as companions, since they don’t really sting.

Can we get an Amazon link in here? Why not? Since we're talking about wasps who may be said to have stingers, but don't have venom, Florence King's study of the Anglo-American Protestant subculture in the 1970s at least has a suitable title:



That's a funny book, but Amazon should be able to do better...I've never seen or read this 1949 book about a real individual mud-dauber, obviously not a Chalybion, but now I want to.