Thursday, May 1, 2014

Exclusive! Important Wasp BOLO

My wife, Heidi, seems to have a knack for finding noteworthy insects at her workplace, the Cheyenne Mountain Zoo. Her most recent discovery is apparently the first confirmed U.S. record of Sceliphron curvatum, an Asian mud dauber wasp in the family Sphecidae. This is a species you need to Be On the Look Out for, and that should be reported to your state or provincial department of agriculture.

Initially, I thought the wasp Heidi captured on April 29 was a blue mud dauber in the genus Chalybion, as it appeared to be dark with few, if any markings, but the container was rather opaque. Removing the wasp from the container and taking images revealed it was actually a species of Sceliphron, of which the native species S. caementarium is locally abundant.

Still, something seemed a bit off. The wasp was indeed dark, devoid of most of the usual bright yellow markings on the legs and body. I quickly uploaded the images to my computer, and posted one on a Facebook interest group for experts in the order Hymenoptera. Meanwhile, I did a little investigating online, and found images in Bugguide.net from Montreal that resembled the specimen.

The Bugguide category is currently “Sceliphron curvatum-or-deforme” because the two species, native to Asia, are apparently difficult to distinguish. I then looked up Google images for S. curvatum and it became clear that the Colorado Springs specimen was at least a close ally of that species.

Back to Facebook. Étienne Normandin of Montreal, and Doug Yanega, an entomologist at the University of California, Riverside, both came to the same conclusion I had, but they have authoritative credentials that I do not.

Sceliphron curvatum is noticeably smaller than our native species, ranging from 15-25 millimeters in body length as opposed to 24-28 millimeters for S. caementarium. Other than size, and differences in color pattern, the two wasps are very similar in their natural history. Each female wasp constructs her own mud nest consisting of one or several cells attached to protected surfaces such as beneath a cliff overhang, under bridges, under the eaves of buildings, or inside old barns. S. curvatum evidently has a propensity for nesting indoors, attaching mud cells to walls, piles of old books, clothing, and furniture. This more “domestic” lifestyle no doubt makes it a prime candidate for spreading far and wide via international commerce. It is easy to overlook a small, earthtone object attached to something.

Mud daubers are predators of spiders, with more generalist tendencies than spider wasps in the family Pompilidae. So, nearly any kind of spider is fair game. Many spiders are paralyzed and piled into a single mud cell before the mother wasp lays a single egg and seals the cell. The larva that hatches feeds on the cache of food, eventually pupating. The adult wasp that emerges then chews its way out of its clay crib

S. curvatum is native to India, Nepal, Pakistan, Kazakhstan, and Tadjikistan, in the foothills of the Himalayas and other mountain ranges. Great. The Front Range of Colorado is essentially the same habitat. It was first reported from Europe in southeastern Austria in 1979. Since then it has spread to Slovenia, Italy, Croatia, Switzerland, France, Hungary, Germany, Serbia and Montenegro, Greece, the Czech Republic, and Slovakia (Bosusch, et al., 2005). Much of its range extension is attributed to the wasp’s own natural dispersal capabilities.

The species has also turned up in and around Buenos Aires, Argentina, as reported in 2008 (Compagnucci and Alsina, 2008). On July 7, 2013, images of a specimen of S. curvatum, next to a mud cell, were posted to Bugguide.net from Montreal, Quebec, Canada, representing the first North American record for the species.

Please put this species on your radar, and maybe pay closer attention to mud daubers in general since it is easy to overlook this newcomer.

Sources: Bogusch, P., P. Liška, J. Lukáš, and A. Dudich. 2005. “Spreading and summary of the knowledge of the invasive sphecid wasp Sceliphron curvatum (Smith 1870) in the Czech Republic and Slovakia (Hymenoptera: Apocrita, Sphecidae),” Linzer Biol. Beitr. 37(1): 215-221.
Compagnucci, Luis A. and Arturo Roig Alsina. 2008. “Sceliphron curvatum, una nueva avispa invasora en la Argentina (Hymenoptera: Sphecidae),” Revista de la Sociedad Entomológica Argentina 67(3/4): 63.

23 comments:

  1. Great article and id-work. And usually I congratulate great observers by saying 'great find!'. But this time? So is the newcomer considered a threat to our local spiders or more a competitive threat to our local mud daubers? And more to the point, if a nest is found, what would the follow-up be? USDA? Do you think it could/ should be contained? I don't see how...

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    1. Thank you. Excellent questions. As far as "invasive species" go, I doubt this one will have much of an impact. However, I think it would be highly instructive to learn how insects like this are being moved, so we can better intercept *real* pest species. Yeah, I should probably contact someone in the USDA.

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  2. Great find! I am the guy who found that wasp in Montreal last year. Hard to imagine that this newcomer is nowhere to be spotted between Québec and Colorado... anyway, if I may, here is a link to a blog post on the subject (more links to most of the post are included):

    http://floraurbana.blogspot.ca/2014/04/lemergence-de-la-pelopee-courbee.html

    It's all in french but you still might find the visuals interesting.

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  3. just showed up in my yard this year in Ct.

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  4. Every summer the wasp comes in my apartment and builds nests... the link will take you to a film where, if you don't see it, you will HEAR it...
    http://floraurbana.blogspot.ca/2016/08/le-buzz-de-la-pelopee-courbee.html

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    1. Thank you for sharing that. It appears this species prefers to conceal its nest rather than use just any surface like our native one does.

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  5. I just killed one of these in my kitchen. I'm in Omaha, NE.

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    1. Please tell me that you kept the specimens and will send them to University of Nebraska entomology department for verification. Otherwise, I, and all other entomologists, remain skeptical of your claim.

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  6. I have been finding these in my home in NW IL. I have killed 3 already as they fly directly toward my kids and me. I am allergic to wasps and hornets and arm myself with an epipen at asp times now. I can't seem to find where they are coming from though.

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    1. From Montreal: for about a week these wasps have been busy again building nests in my book shelvings. As usual, they really don't seem to care about the guy (me) working on the computer. I have no screens in my windows so they're in and out, adding layers of mud to their cells. These will soon be filled with paralysed spiders. All this construction work and provisioning of spiders to the cell requires a lot of in and out of my office. But compared to paper wasps they are quite discrete. Native mud daubers barely fly in and get out immediately, they are not interested! This new species has some interesting adaptations to human interiors. Note that I am not suggesting that you should be imprudent...

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  7. One has been coming to my green onions blooms in Denham Springs, LA, outside of Baton Rouge. Sounds like this type prefers cooler weather. Maybe it accidentally rerouted in a coolfront that came in last week that brought the temp from 97 down to 86.

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    1. This wasp should NOT be in your region. You are most likely seeing a related species or genus.

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  8. I'm in my 60s and have never seen one here in South Louisiana before. Has anybody else from this area seen them here?

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  9. I have a mud nest right above my front door (I live in Aguascalientes, Mexico), I'm not sure what type of wasp built it. From what I've read in several websites, it should contain only 1 egg, does anyone know what happens after the wasp hatches? I don't want to destroy the nest unless I really have to, I'm hoping the wasp will fly away and never come back once it's born, but if it's going to stay there after it hatches then I will have to destroy the nest because I don't want to put my family at risk.

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    1. If the nest is mud, then it will likely house only a single wasp offspring, which will hatch several weeks to a year later. Solitary wasps like that pose no threat whatsoever. Social wasps like paper wasps are also usually harmless, though over a doorway they could be problematic.

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  10. My cat has been playing mouse with what looks like this bug. I live in Pennsylvania. I have killed several this month. I attribute it to my numerous plants that sit outside during the summer and bring into my sunroom every winter. Do the sting? How do I treat my plants?

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    1. No need to treat anything, these are beneficial insects (and I would be surprised if this particular species is the one you found). Females can sting, but only if you grab one. They are alert and very quick to fly away rather than sting.

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  11. I killed one in my house window yesterday! Elizabeth City, NC

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  12. I just found some in my wood pile, just north of Detroit.

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  13. Who do I report finding one in my camper in Nc to because I'm not sure

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    1. It would be your state department of agriculture, but you'd need to present at least a clear image, and preferably a specimen.

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  14. I just killed one in my camper in North Carolina

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