Wednesday, August 8, 2012

Wasp Wednesday: A Real Surprise

I am certainly finding the Front Range region to be exceptionally diverse when it comes to wasps, but nothing could have prepared me for what I found in the field yesterday, August 7. I was looking over a White Sweet Clover (isn’t there a song about that?), when a very large wasp commanded my attention. I immediately recognized it as a paper wasp, but not a species I would have expected in Colorado Springs.

This is a male specimen of Polistes carolina or Polistes perplexus. Either way, it is most likely going to turn out to be a county record, potentially a state record, and perhaps even a range extension. Both species are recorded for Kansas, so what is a couple hundred more miles or so?

I also managed to collect the specimen, so I’ll be able to eventually examine it under a microscope for the details necessary to separate the two species. Until very recently, it was thought that the males could not be distinguished at all, but apparently there are transverse (horizontal) ridges on the propodeum (hindmost segment of the thorax) that are weak in P. carolina and much more evident in P. perplexus. Watch this space for the final determination of the species.

For now, I’m ecstatic over this discovery. I’d sure like to find the nest this fellow came from. Females are a little easier to identify, and finding the nest would verify that this is a species breeding here. Even so, this male is in immaculate condition, suggesting it did not travel a long distance.

Because these two species were once thought to be a single species (P. carolina), most documentation of their biology is somewhat suspect. Polistes carolina apparently nests in exposed situations, such as under the eaves of buildings, for example; and reports of that species nesting in hollow trees and other protected locations actually apply to Polistes perplexus. Prey is probably similar in both species, consisting mostly of caterpillars chewed up by the adult wasps and fed to the larvae in the nest. Still, wasps this large can probably tackle much larger prey, and a single record of an attack on a cicada (Tibicen auletes) could be for either species of wasp.

I find that in current literature the size of these wasps is measured by the length of the forewing, which is 15-20.5 millimeters in P. carolina, and 17-21.5 millimeters in P. perplexus. Contrast this with the measurements of the abundant and widespread Northern Paper Wasp, Polistes fuscatus. Forewing length for that species averages between about 13 and 17 millimeters.

Polistes carolina is most common in the southern U.S., but ranges from New York, Pennsylvania, and Ohio south to Florida and west to Illinois, Kansas, Arkansas, and eastern Texas. There is one record for Ontario, Canada, but the species is not established there. That could be the case here in Colorado, too: a fluke. P. perplexus ranges from Maryland to Georgia, and west to southern Illinois, Kansas, Oklahoma, and Texas. One recent record has come from Pennsylvania.

Keep your own eyes open for species that seem “misplaced.” Interstate (and international) commerce, climate change, and other factors are changing the distribution patterns and abundance of many species. We also haven’t looked that closely at insect species with little or no economic impact. You stand a good chance of adding to our collective knowledge with relatively minimal effort.

Source: Buck, Matthias, Stephen A. Marshall, and David K.B. Cheung. 2008. “Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of the northeastern Nearctic region,” Canadian Journal of Arthropod Identification No. 5: 492 pp (PDF version).

12 comments:

  1. Nice find. This wasp -er- these two wasps are my favorite Polistes, big & a handsome shade of red, with snazzy, blue-black wings - What's not to like? They seem to be particularly abundant around here this year; I'm seeing them almost as often as "P. metricus" (also now two species, I hear).

    In all my years living within the geographic range of these wasps, I've only encountered a single nest (accidentally, while ant hunting), in a concavitiy on the underside of a large rock, in a prairie in southwestern Missouri -- Never one on an eve or any other exposed site. I've seen a few disappear into a wall space in a rustic cabin, or the like.

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  2. Yes! That is amazing. I'm always fascinated by insects and the like, so whenever I see something I've never seen before (living in the same state for 26 years) I must inquire. Because now more than ever species seem to be crossing lines and going places never before, as you said due to many factors. The main culprit, when looking at the whole of the problem is humans of course. It is so facsinating to me to see insects and animals where they don't usually belong, There are so many questions and couriousities. I can't wait to hear more on this wasp, I hope you post an update on him :)

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  3. Thank you, Lydia! There *will* be an update, but it turns out this is far more complicated than I initially thought. Stay tuned :-)

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  4. We found 5 what I believe to be Polistes perplexes wasps in an upside down bucket in our yard in New Jersey today. I have not seen this wasp here before, and I am wondering if this is signigicant enough to report. Please let me know. Thank you in advance.
    Alison
    AliFragale@gmail.com

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    1. Alison: Turns out that there may be more than two species involved here (P. perplexus, P. carolina, and potentially others). Plus, there are other large, red wasps in your area, like Tachypompilus ferrugineus. Lastly, for a "report" to count, a specimen is needed, or at least a very clear, detailed image. Thank you for being observant, though!

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  5. While tending to my back yard today, I found hundreds of these red wasps gathering on the eaves of my house, on the east side of the house, at the south end. I have never seen this many wasps in one place, and it appeared as though many of them were battling each other. Why are there so many and why are they gathering in one location. Seriously, there were hundreds.

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    1. Male paper wasps often congregate at the tops of tall objects, where they compete to intercept available females. That is most likely what is going on in your case, too.

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  6. Saw two of these this am! North Denver

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    1. With all due respect I would be extremely surprised. There are certain ichneumon wasps (Spilichneumon sp.) out right now that look similar to these paper wasps, but much smaller and far more common.

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  7. I realize that this is quite a few years old now, so these words are likely more widespread. Have you found out anything more... Like... How to make them go away? :-) I am almost POSITIVE these are what plagued my house last fall. I know they aren't ichneumon...

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    1. Without seeing a clear image or, even better, a specimen, then I cannot make an identification. I also never dispense "pest control" advice except for prevention.

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