Friday: 1 June 2007
The wasps have made their appearance in the last few weeks, first the paper wasps, and then in the last couple of days potter wasps and mud daubers.
As she did this she emitted a loud whining buzz, but not apparently associated with her wings.
As you probably already know, in the next stage she’ll lay an egg and provision it with some poor paralyzed spider, and the larva will feed on that during its development.
Mud daubers are solitary wasps, with the adults apparently feeding on nectar to support their prodigious progeniferous program. I present that link, not as a sole reference for that little factoid, but because the xenophobia interested me. For a considerably more friendly and informative investigation, go to the always interesting Hilton Pond.
But the males get involved here too, and in the insect world that’s always worth mentioning. A male will hang around a female building a nest, and, presumably hoping for some, will in the meantime protect the nest and chase off rubberneckers.
Two worthwhile words: bivoltine, and diapause.
I ran across the first one musing through this abstract on populations of mud daubers. It essentially means that there are two generations per breeding season.
The word probably derives from “bi”, meaning two, of course, and you can use “uni”, "tri", and “poly” as a prefix, coupled with (probably) “voltus”, meaning appearance. So: two appearances (or one, three, many).
What’s interesting about mud daubers is that they’re bivoltine south of a certain climatological line, and univoltine north of that line, with only one generation. Ours are almost certainly bivoltine. That means that the second generation is going to have do something different from the first generation, in order to get through the winter.
That’s where “diapause” comes in. The etymology here is Greek, not Latin, and the “dia” prefix doesn’t mean “two”, it means “through” or “across”. So it’s a pause through or across. (As opposed to “menopause”, where “meno” refers to “month” or “moon” and the “pause” here derives from a word meaning “to bring to an end”, a gratifying result, at least once it’s over.)
It’s essentially a form of hibernation. In this case it means that the mud dauber larvae will cease development, cued apparently by environment, for the winter period, and will resume development with warming temperatures, increasing photoperiod, or some such.
So the first generation in a breeding season doesn’t do a diapause, at least not in the same way that the second generation does. And north of that line, the mud daubers all do diapause at the end of the much truncated warm season.
This brings up a fascinating concept - reproductive isolation. Conceivably organisms that are bivoltine could become reproductively isolated from each other, which means that for whatever reason, they cease mating between generations in a single season. This can herald the start of speciation, in which the first and the second generations, no longer able to mate, begin to diverge and change.
(In the case of mud daubers, this doesn’t happen - according to that abstract linked to above, mud dauber males do survive across the two generations and so they do not become isolated reproductively. That abstract also summarizes transfer experiments where bivalent populations were carted north, and vice versa, and demonstrated that the eggs in the first generation in the south will undergo diapause when transported to the north. So it’s clearly a set of environmental cues that control diapause and both the north univoltine and the south bivoltine populations are capable of either behavior.)
Both voltine and diapause behavior are very general terms and apply to much more than just insects, extending from much lower animals than insects and into mammals even. Here are some extreme examples among insects, for instance, that might have diapause lasting for many years.
Oh yes, the problem. She’s building her nest in the kitchen. We typically keep our “front door”, the kitchen door, open at all times that the weather is not inclement (and then some, too). Since the screen door went away some time back she apparently felt it an invitation. Which means that she investigated the kitchen, found a place, decided “oh yes, perfect”, and then memorized the location, and how to get in and navigate the kitchen.
We probably wouldn’t be so free if we lived in an urban or suburban area where houseflies, mosquitos, and what not abound, but other than the stray possum seldom get invaded.
It does raise the question of what we’re going to do with this first generation nest, which will probably hatch out in a month or two if we don’t get rid of it. I do hate for her efforts to come to nothing.
 | Yesterday we watched a Pipe Organ Mud Dauber (or dirt dauber or dobber, whichever you prefer), presumably Trypoxylon politum, building her nest. She was tireless, bringing in balls of clay mud every few minutes all afternoon, and spending about a minute on each trip constructing the nest. There’s a little problem with this nest, but I’ll get to that in a bit. We’ve talked about mud dauber nests before, but only as artifacts. The photo to the left shows her just after she landed with a ball of mud, and the thumbnails below are to photos in a new page that show the stages of her spreading her efforts in this single trip. Apparently she decided this ball should be used for extending the foundation, rather than adding to the arch. |
As she did this she emitted a loud whining buzz, but not apparently associated with her wings.
As you probably already know, in the next stage she’ll lay an egg and provision it with some poor paralyzed spider, and the larva will feed on that during its development.
Mud daubers are solitary wasps, with the adults apparently feeding on nectar to support their prodigious progeniferous program. I present that link, not as a sole reference for that little factoid, but because the xenophobia interested me. For a considerably more friendly and informative investigation, go to the always interesting Hilton Pond.
But the males get involved here too, and in the insect world that’s always worth mentioning. A male will hang around a female building a nest, and, presumably hoping for some, will in the meantime protect the nest and chase off rubberneckers.
Two worthwhile words: bivoltine, and diapause.
I ran across the first one musing through this abstract on populations of mud daubers. It essentially means that there are two generations per breeding season.
The word probably derives from “bi”, meaning two, of course, and you can use “uni”, "tri", and “poly” as a prefix, coupled with (probably) “voltus”, meaning appearance. So: two appearances (or one, three, many).
What’s interesting about mud daubers is that they’re bivoltine south of a certain climatological line, and univoltine north of that line, with only one generation. Ours are almost certainly bivoltine. That means that the second generation is going to have do something different from the first generation, in order to get through the winter.
That’s where “diapause” comes in. The etymology here is Greek, not Latin, and the “dia” prefix doesn’t mean “two”, it means “through” or “across”. So it’s a pause through or across. (As opposed to “menopause”, where “meno” refers to “month” or “moon” and the “pause” here derives from a word meaning “to bring to an end”, a gratifying result, at least once it’s over.)
It’s essentially a form of hibernation. In this case it means that the mud dauber larvae will cease development, cued apparently by environment, for the winter period, and will resume development with warming temperatures, increasing photoperiod, or some such.
So the first generation in a breeding season doesn’t do a diapause, at least not in the same way that the second generation does. And north of that line, the mud daubers all do diapause at the end of the much truncated warm season.
This brings up a fascinating concept - reproductive isolation. Conceivably organisms that are bivoltine could become reproductively isolated from each other, which means that for whatever reason, they cease mating between generations in a single season. This can herald the start of speciation, in which the first and the second generations, no longer able to mate, begin to diverge and change.
(In the case of mud daubers, this doesn’t happen - according to that abstract linked to above, mud dauber males do survive across the two generations and so they do not become isolated reproductively. That abstract also summarizes transfer experiments where bivalent populations were carted north, and vice versa, and demonstrated that the eggs in the first generation in the south will undergo diapause when transported to the north. So it’s clearly a set of environmental cues that control diapause and both the north univoltine and the south bivoltine populations are capable of either behavior.)
Both voltine and diapause behavior are very general terms and apply to much more than just insects, extending from much lower animals than insects and into mammals even. Here are some extreme examples among insects, for instance, that might have diapause lasting for many years.
Oh yes, the problem. She’s building her nest in the kitchen. We typically keep our “front door”, the kitchen door, open at all times that the weather is not inclement (and then some, too). Since the screen door went away some time back she apparently felt it an invitation. Which means that she investigated the kitchen, found a place, decided “oh yes, perfect”, and then memorized the location, and how to get in and navigate the kitchen.
We probably wouldn’t be so free if we lived in an urban or suburban area where houseflies, mosquitos, and what not abound, but other than the stray possum seldom get invaded.
It does raise the question of what we’re going to do with this first generation nest, which will probably hatch out in a month or two if we don’t get rid of it. I do hate for her efforts to come to nothing.
