I came across this magnificent spider wasp (Pompilidae) feeding on nectar from these flowers beside the steps leading up to Wat Tham Pha Plong, Chiang Dao, Thailand. I have come across this pompilid wasp before in northern Thailand (1), but I am still not sure what species it is. With its orange antennae, it looks similar to the Australian orange spider wasp (Cryptocheilus bicolor) (2), but the head is not orange and the abdomen is black. So perhaps it is another Cryptocheilus species, of which there are twenty-four known. One website provides a check-list of pompilid species from Thailand (3), but none of these seem to fit the bill. Other sites, simply caption photos ‘Pompilidae’, so it is not one that can be identified from of the Internet. If there are any pompilid experts out there, I would love to know what it is!
Adult pompilid wasps feed on nectar, but they hunt and kill spiders to provide a food source for their off-spring. They sting and paralyse spiders and carry them off to a nest burrow, where they deposit an egg on the hapless arachnid. Each offspring has its own spider to gorge on. The wasp larva hatches out and starts feeding on the living, paralyzed spider. The bigger the spider, the more likely it is that the larvae will develop into a female wasp (which are larger than males).
I would think that there is much to learn about these wasps, particularly species which have been little studied. The are nearly all solitary wasps although a few communal, mud-nesting species exist (4). The hunting behaviour of one group of pompilids, the tarantula hawk wasps – which occur in the deserts of the USA – has been studied: “the wasp rushes at the spider, grabs a leg, flips the spider onto its back, and stings it….” The tarantulas can mount a counter attack, but it seems they are at a disadvantage and rarely succeed in killing the attacking wasp. (5) One can only wonder at how long this evolutionary battle between wasps and spiders has played out over geological time.
Some pompilid wasps are cleptoparasitoids; they steal the spider prey caught by other pompilid species. They wait until the wasp which has caught the spider puts it down and turns its attention to nest making; they then rush in and lay their own egg on the spider. This egg hatches out before the one laid by the wasp which first caught the spider, and the imposter larva eats the host egg before it hatches. (5) Very sneaky!
Some pompilids prey on species such as this orb spider, Argiope pulchella (6). The spider is sitting in the middle of an X-shaped stabilimentum; an elaborate web decoration or feature which it has constructed out of silk (below).
I don’t know how poisonous the sting of this particular wasp I photographed would be to humans; and I would not like to find out.
Pompilids are not aggressive and are usually relatively docile (unless provoked), but the sting of the closely related Tarantula hawk wasps is reportedly very intense. The pain has been described as: “like an electric wand that hits you, inducing an immediate, excruciating pain that simply shuts down one’s ability to do anything, except, perhaps, scream.” (7)
One has to admire the skill and tenacity of these wasps, which often prey on spiders which are much larger than themselves, and highly venomous. They have evolved a way of exploiting this prey source and presumably play an important role in regulating spider populations.
Butterflies, like this Clipper (Parthenos sylvia) also enjoy feeding on the flowers of this plant.
- https://rcannon992.com/2013/11/23/a-two-tone-wasp/
- http://www.brisbaneinsects.com/brisbane_vespoidwasps/OrangeSpiderWasp2.htm
- http://insectoid.info/checklist/pompilidae/thailand/
- http://www.usu.edu/pompilidweb/default.htm
- O’Neill, K. M. (2001). Solitary wasps: behavior and natural history. Cornell University Press.
- https://www.flickr.com/photos/phil_arach/galleries/72157651182275337/
- http://www.desertusa.com/insects/tarantula-hawks.html
Ray Cannon's nature notes 
[…] Source: Pompilid spider killer […]
Great group of wasps! I know them mainly from South Africa where they are important pollinators in the Eastern grasslands in particular. What’s the plant? Some kind of Euphorbia perhaps?
I haven’t managed to identify this plant yet. Its a sort of spiny succulent, with these very characteristic flowers.
I’m pretty sure it’s a Euphorbia (or a related genus in the same family) – the 3-part pistil and the surrounding nectar glands are very characteristic.
May I ask specifically how large this wasp was, or a close relative estimate? Despite scouring the web and finding virtually nothing that reasonably mirrors this wasp in location and physicality, I think the best assessment of this wasp is that of a Hemipepsis subspecies, which are among the classical “tarantula hawk” genera. I arrived at this conclusion after fortunately stumbling upon an image of the comparison of the patterns of wing venation between Pepsis, Hemipepsis, Entypus, and Calopompilus spider wasps; I also read that the wing venation patterns are some of the primary distinguishing features used to identify distinct genera of these wasps. I did some quick reformatting of your second picture of this wasp so that it could be displayed as a right-hand mirror image of any of the four left wings that this comparison featured. After some heavy scrutiny, it became clear that your mystery wasp has wing patterns that are nearly a perfect mirror image of the wings of the Hemipepsis genus, so in all likelihood this is the genus of Pompilid spider wasps to which your wasp belongs. Further support for this classification comes from the legs, which are far longer than those in the Entypus genus, and the head, which is less rounded and more closely resembling of Hemipepsis anatomy.
As for the species of hemipepsis, considering geographical proximity to Thailand where this was found, it could be any of the following species that have ranges throughout India or Southeast Asia.
Hemipepsis: bellicosus, acer, convexa, aenea, audax, ceylonicus, elizabethae, eximia, fenestratus, flavopicta, fulvipennis, indica, intermedia, laetal, lusca, obsonator, odin, perplexa, procera, sogdiana, sycophanta, veda, venatoria.
However, the closest visual approximations of this wasp I’ve found on the internet are Hemipepsis brunnea (found in the middle east) and Hemipepsis capensis (found in South Africa), but due to the geography it’s likely the true identity is among those 23 species.
Hope this helps!
Sources:
https://bugguide.net/node/view/703332 (Wing comparison)
https://en.wikipedia.org/wiki/Hemipepsis
https://bugguide.net/node/view/3920
https://bugguide.net/node/view/3921
https://bugguide.net/node/view/1156062
Thank you very much for taking the trouble to identify this wasp as best you can. I remember it being quite large, but exactly how large I am a bit vague about! You can compare it to the Clipper butterfly on the same plant species (taken on a different date). The Clipper has a wing span of about 10 cm. The pompilid wasp could have been about 3 cm from head to tip of abdomen? I hope I will see it again!
Of course! That size definitely is consistent with large pompilids like hemipepsis. Hopefully more information will eventually find its way to the internet or various entomology resources, as I can’t stand an unsolved mystery. Amazing pictures by the way!
[…] Here is a lovely spider wasp (below) with long, flexible antennae which it can clearly manipulate very well. These pompilid wasps are spider killers! […]