Tag Archives: entomology

Gallery of bee hotel visitors

Here are some of the pics I’ve taken at bee hotels over the past several years. Sharing in case other beekeepers might recognize residents in their own hotels. There were bees, as one would expect, but also wasps, flies, and beetles.

Horn-faced mason bee (Osmia cornifrons)

Horn-faced mason bee (Osmia cornifrons). Very common at my hotels. Introduced from Asia in the 1970s. Details at BugGuide.

Taurus mason bee (Osmia taurus)

Taurus mason bee (Osmia taurus) are also common and also introduced. Details at BugGuide.

Giant resin bee (Megachile sculpturalis)

Giant resin bee (Megachile sculpturalis). Yes, also introduced, though more recently (~1994). Details at BugGuide.

Mock-orange scissor bee (Chelostoma philadelphi)

Mock-orange scissor bee (Chelostoma philadelphi). So named because it prefers to collect pollen from trees in the genus Philadelphus (mock oranges). This is the only native member of the genus in the United States. Details at BugGuide.

Ancistrocerus antilope

Ancistrocerus antilope has shown up a few times at my hotels, but apparently prefers to nest in sumac and elder stems. It also is reported to use old mud-dauber nests. They are fun to watch because they provision nests with caterpillars. Details at BugGuide.

Euodynerus "Species F"

This is Euodynerus “Species F” at the moment. I.e., it’s one of several undescribed species in the genus (details here). Its biology is apparently unknown, so I’m hoping to get more of them in the future.

Parancistrocerus histrio

Parancistrocerus histrio is another wasp that feeds caterpillars to its brood. Details at BugGuide.

Auplopus mellipes

Auplopus mellipes provisions its nests with spiders. For a wonderful overview of their biology, please see post on Eric Eaton’s blog. (While there, I noticed he has a new book on wasps.)

Euodynerus schwarzi

Euodynerus schwarzi provisions nests with caterpillars. For identification tips, see blurb by Matthias Buck et al.; more pics are at BugGuide.

Euodynerus megaera

Euodynerus megaera is extremely similar to the above species but has black tibiae. At least females do (males are much harder to distinguish). It’s also a collector of caterpillars. More details by Buck et al.

Brown-legged grass-carrying wasp (Isodontia auripes)

Brown-legged grass-carrying wasp (Isodontia auripes) provision their nests with tree crickets. As their name suggests, they also carry grass, which they use to pack and seal the brood chamber. Details on BugGuide.

Grass-carrying wasp (Isodontia sp.)

Here’s a photo of the grass-carrying wasp’s nesting plug that I took at Longwood Gardens. They have a beautiful bee hotel with hundreds of cells but as far as I could tell, only a few wasps had moved in.

Trypoxylon collinum

Trypoxylon collinum provision their nests with spiders. Unlike many wasps and bees, the males in this genus actually help out around the nest. For details, please see this Instagram post. BugGuide has a page for the species but it contains little information.

cuckoo wasp (Chrysis sp.)

Cuckoo wasp (Chrysis sp.). They are absolutely adorable. That said, they are also parasites of the above bees and wasps that are nesting at the hotel. They are very difficult to identify, so even getting them down to genus is rare. Here’s BugGuide’s page on the family.

club-horned cuckoo wasp (Sapyga louisi)

The club-horned cuckoo wasp (Sapyga louisi) is another frequent parasitic wasp at my hotels. This one is patiently waiting to gain entrance to the nest of a mock-orange scissor bee. Details on BugGuide.

Leucospis affinis

Leucospis affinis is another parasitic wasp that is almost always lurking around my bee hotel. It’s oddly variable in size. More details by Ari Grele at Insects of Cornell, at BugEric, and BugGuide.


Monodontomerus sp. (in Chalcidoidea) are extremely common parasites of mason bees. Please see this post at Nurturing Nature for great video and description of their life cycle. Additional details at BugGuide.

Digonogastra sp.

Digonogastra sp. These braconid wasps are parasites, but I’m not positive the ones I’ve seen at my bee hotels are targeting any of the residents. But they’ve shown up on at least two occasions so I think it’s a possibility.


Amobia sp. are flesh flies that develop on the provisions inside (for example) Trypoxylon nests. I’m not sure whether the larvae also eat the wasp larvae, but I’d suspect so. Details at BugGuide.

Houdini fly (Cacoxenus indagator)

Houdini flies (Cacoxenus indagator) are newly introduced to the United States and are likely to ravage mason bee nests and the crops that depend on them for pollination. If you have bee hotel, this fly is reason #1 why you should use removable paper tubes that allow sorting of infested and uninfested brood cells. Without paper tubes your bee hotel will likely be a Houdini fly hotel. Crown Bees has information on how to clean your tubes.

Skin beetle (Dermestidae)

Skin beetles (Dermestidae) are scavengers but can become serious pests of uncleaned mason bee hotels. Yet another reason to use only paper tubes fitted inside drilled holes, combined with a thorough cleaning of entire hotel (e.g., soak in bleach, scrub). Details on skin beetles at BugGuide.

The above is probably less than 1% of the species that might be found at a bee hotel that had a range of nesting-hole diameters. Noticeably absent are leaf-cutter bees, so that’s my photo resolution for 2021.

Note that almost everyone calls these hotels “bee hotels”, but in my experience the majority of the residents are wasps. That’s totally fine with me. Wasps are pollinators, too. And wasps tend to be more photogenic and possess more interesting life histories if you ask me. In related news, I’m really looking forward to reading Heather Holm’s new book, Wasps: Their Biology, Diversity, and Role As Beneficial Insects and Pollinators of Native Plants.

For my full collection of photos at bee and wasp hotels, please click on button below.

Experiments on Spartan Mosquito Eradicators

Research conducted in Florida found no evidence that Spartan Mosquito Eradicatiors are effective mosquito-control devices. Here’s the citation:

Aryaprema, V.S., E. Zeszutko, C. Cunningham, E.I.M. Khater, and R.-D. Xue. 2020. Efficacy of commercial toxic sugar bait station (ATSB) against Aedes albopictus. J. Florida Mosquito Control Association 67: 80-83. PDF

Laboratory experiment

Below is a rough reconstruction of the laboratory experiment they conducted. In each of the cages (BugDorm-2120), 100 male and 100 female tiger mosquitoes (Aedes albopictus) were released, then monitored for mortality at 24, 48, and 72 hours.

Schematic of laboratory experiment based on description in Aryaprema et al. 2020.

Below are the cumulative mortality data for the three cages. Result: the Spartan Mosquito Eradicator filled with the provided packet ingredients (treatment) did not result in higher mortality. I.e., there was no evidence the device killed mosquitoes under laboratory conditions.

Field experiment

The researchers also conducted a field experiment using two sites that had large populations of tiger mosquitoes (because of the presence of tires). At each site they deployed five tubes (separated by 4 m), switching whether the tubes were “treatment” or “control” tubes every 2 weeks. A BG-Sentinel trap (without carbon dioxide) was used to quantify mosquito numbers every week.

Schematic of field experiment based on description in Aryaprema et al. 2020.

Below are the weekly numbers of mosquitoes caught in the BG Sentinel traps. Results: there was no evidence that presence of treatment tubes (filled as per company guidelines) reduced the numbers of mosquitoes at the sites.


The scientists concluded that “Both laboratory and field components of our study show that the Spartan Mosquito Eradicator is not effective in reducing abundance of Ae. albopictus.” They speculate that the contents do not attract mosquitoes and that the holes on the device (~3 mm) are too small for mosquitoes to easily reach the fluid inside. They also highlight the need for an experiment to evaluate whether the active ingredient (1% sodium chloride) kills adult mosquitoes. I.e., even if mosquitoes were attracted to Spartan Mosquito Eradicators and could easily get inside, the salt might not be lethal.

Update: the salt experiment has been conducted.

Photographs from Ridley Creek State Park

Last week when I was at Ridley Creek State Park I crossed paths with a tree tour led by wildlife biologist Gary Stolz (PA Dept of Conservation and Natural Resources). I promised the group that I’d post photographs of things I’d seen at the park. Here are the highlights:

Long-tailed giant ichneumon wasp

Long-tailed giant ichneumonid wasp (Megarhyssa macrurus)
Megarhyssa macrurus

The largest and most colorful was clearly the long-tailed giant ichneumon wasp (Megarhyssa macrurus) that I found ovipositing into a red maple. Actually, there were perhaps a half-dozen of them, all presumably targeting the larvae of Tremex columba (a sawfly) that were busy eating the tree. The presence of the sawflies is given away from probably a mile away (I’m guessing here) due to the odor of the symbiotic fungus they use to help digest the wood. Once on the tree, though, the ichneumon probably locates a larva by sensing the vibrations it makes when chewing. The ovipositor is approximately 2″ long and is tipped with a cutting edge (as you might guess). It also drips out a fluid that helps dissolve the wood. An amazing insect to watch.

Green’s giant ichneumon wasp

(Green's giant ichneumonid wasp) Megarhyssa greenei
Megarhyssa greenei

Also on the same tree were several Green’s giant ichneumon wasps (Megarhyssa greenei). This species has a shorter ovipositor (among several other differences) but does pretty much the same thing as the species above.

Unknown wasp in Tribe Ephialtini

Ovipositing wasp in Tribe Ephialtini.

Also beautiful but much smaller (perhaps 12 mm), I found this wasp ovipositing into a nearby tree that was completely dead and covered with moss. I’m still working on an ID (it’s something in the Ephialtini). Which means, like many of the insects I photograph, I’m hoping that an expert will eventually help me identify it. Sometimes that process can years but I’ll update this page if there’s any movement. For those curious, I post photographs to iNaturalist and BugGuide for help. And I often ask my Dad (Foster Forbes Purrington), an entomologist.

Coelichneumon navus

Coelichneumon navus (female)
Coelichneumon navus

The last wasp of the day is Coelichneumon navus, another ichneumonid but with a concealed ovipositor. This species has been known to parasitize fall webworm (Hyphantria cunea) and cypress looper moth (Iridopsis pergracilis), but like many of the 100,000 or so members of the family Ichneumonidae not much is known about its natural history. I found two caterpillars on this tree but haven’t yet ID’d them.

Gnophomyia tristissima

Gnophomyia tristissima
Gnophomyia tristissima

Another insect with no common name, Gnophomyia tristissima live, love, and die around rotting hardwood logs. These are crane flies and can be identified by their bright yellow halteres (remnants of their second pair of wings) and black bodies. This photograph shows mating but afterwards the male seems to guard the female while she oviposits (if you want to see that, click on image to be taken to a site that has additional photographs). I spent about 30 minutes watching and photographing them and could have stayed longer. But the mosquitoes were exsanguinating me.

American nursery web spider

American nursery web spider (Pisaurina mira)
Pisaurina mira

Earlier on my walk I found a rather orange American nursery web spider (Pisaurina mira). It was also rather large.

Banded fishing spider?

Juvenile banded fishing spider (Dolomedes vittatus)
Dolomedes vittatus?

I can usually narrow down spiders given their eye arrangement and details of web (or lack thereof), but this is stumping me. My tentative guess is that it’s a freshly-molted (teneral), juvenile banded fishing spider (Dolomedes vittatus). I’m trying to get this confirmed so check back if you’re curious. Astute readers will notice that it’s on a tree, not near water, but apparently there are few members of Dolomedes that can live away from water just fine. This is one of those species.

Northern water snake

Northern water snake (Nerodia sipedon)
Nerodia sipedon

This was the first time I’ve seen a northern water snake (Nerodia sipedon) but apparently they are super common. This one was perhaps 2 feet long but they get as big as 4 1/2 feet. Non-venomous, though, in case you were wondering.

Sulphur tufts?

Sulphur tufts (Hypholoma fasciculare) on log
Hypholoma fasciculare?

I’m still working on an identification but my current guess is sulphur tufts (Hypholoma fasciculare). Or, if you prefer, sulfur tufts. I really enjoy photographing young mushrooms but the consequence is that they are harder to identify.

That’s it! If you have any questions, send me a note or leave a comment.