Hello everyone!
We have been busy in the lab preparing for spring field season. Many people are reporting their first bees of the year, with many seeing mason bees (Genus Osmia), mining bees (Genus Andrena), and a small number of sweat bees (Genus Lasioglossum). Another side project in the lab is creating stem nests, which we have finally completed, with 60 nests ready to go!
Behold our hoard of stem nests that we hope to use to trap cavity nesting bees.
We have also been carving away at the many Lasioglossum specimens from the bee bowl project and specialist bee project. We identified over 800 specimens last week, which is a good rate of progress!
Here are a few of the Lasioglossum that we have been working through.
One of our most common species is Lasioglossum hitchensi. For our ID blog 2 weeks ago, we described it as follows:
“scutum punctures dense lateral of parapsidal line and sparse between, t1 fan COMPLETE, mesepisternum ruglose (not punctate), Clypeus with distal margin WIDE (rectangular!!) = mitchelli –> now hitchensi ! Dirt common bee”
I tried to get better photos of the clypeus margin and acarinial fan.
The angle on the head can be hard to see as it is often obscured by hair. I often find myself moving them just right under the light to see the structure better.
Another important (albeit sometimes variable as hairs rub off), character is the complete acarinial fan on the first abdominal segment. The hairs create a bridge that is rarely interrupted. The integument also typically has slight microsculpture that makes it seem slightly dull in this area compared to most other Dialictus bees.
Lasioglossum pectinatum – Specialist Lasiglossum on Physalis?
Another cool find from our specialist bee project was 2 specimens of Lasioglossum pectinatum, which are thought to maybe be specialist bees on ground cherries and related plants. One of our specimens was caught on Physalis, but the other was caught on Helianthus (but at a site known to have a lot of Physalis). If you are familiar with tomatillos, you have seen Physalis.
This is one of the black Lasioglossum bees that lacks any metallic reflections. It has a distinctly long face and the inner tibial spur has many tiny teeth (compared to most of the other black Lasioglossum which typically only have 4-5 teeth on the inner tibial spur).
Look at this long face! Not many Lasioglossum have a clypeus extending that low below the face, so this is quite striking!
Note the many short teeth on the inner tibial spur.
Strepsiptera mystery!
These little bulges sticking out of the abdomen are female strepsiptera. It is not common to find strepsiptera in Lasioglossum.
Another challenge we have run into is a weird Lasioglossum that has been parasitized by strepsiptera. These parasites often munch on gonads, which cause the host bee to look not quite female and not quite male. This makes identifying the specimen to species challenging as many of the identification characteristics are different between males and females.
The scutum on our host bee is very shiny, which is unusual for our most common Lasioglossum females.
As an example, the scutum (large plate on back of bee) is often dulled with microsculpture in most female Lasioglossum, but often very shiny in males of the same species. But there are some species of Lasioglossum that have females with shiny scutums, although they are not as common. So is our parasitzed bee just a weird looking form of a common species (I’m betting L. versatum), or is it a less common species that just happens to have been parasitized? We aren’t sure yet. We might need to use DNA instead to officially find out the answer. In the meantime, we will hold onto it and try to get a few other experts to take a look at it.
All for now,
MaLisa
Interesting conundrum with the parasitized specimen. And curious about the Physalis visitor also on Helianthus. So, do some specialist bees just prefer one type of host plant but also visit others while other specialists only visit their one host plant? Like a facultative vs obligate sort of thing?
Yea, some specialist bees can occasionally be found on other plants, but they might not be able to successfully rear young on these other plants. I’ve collected the spring beauty specialist and then found it to have pollens from other plants later in the season once most of the spring beauties are gone.
We can’t solidly say for sure without intentionally designing studies to investigate each species, which is outside of the scope of our current project.
Ah ok, sure. Interesting. Thanks MaLisa!