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Bombus Bumblebee ?? - Bombus insularis - female

Bombus Bumblebee ?? - Bombus insularis - Female
NW, Wyoming, USA
June 24, 2004

Was this really from Wyoming in January?

wrong date
Ooops. Interesting, you were the only one that commented on the date. It was actually June, 2004. Sorry about that.

It showed up as an outlier for Wyoming images. So June 24, 2004 then?



Psithyrus insularis (Apidae)
Yes, a cuckoo bee. The side patches at the apex of the otherwise black abdomen are diagnostic for P. insularis.

species ID looks correct
but cite as Bombus (Psithyrus) insularis

Definitely a Psithyrus sp., female
Congratulations to Mr. Burke for this picture. The shape of the last gastral sternite, combined with the scarcity of the fur on the basis of the gaster, clearly indicates a female cuckoo bumblebee. Moreover, the hind tibia of a "true" Bumblebee would be much broader and more shiny, with distinct long hairs around the "tibial basket" - which is lacking here, the outer face of the tibia being convex rather than flat. This species looks very similar to our own (here in Europe) P. campestris and P. barbutellus, to which it is obviously closely related. It should parasitize mainly long-tongued Bumblebees (Megabombus sp.), such as Megabombus pennsylvanicus - whose overall color is very similar.

Megabombus is no longer considered a genus
the usual parasite of B. pensylvanicus in the SE USA is Bombus (Psithyrus) variabilis

Is B (P) insularis.
The N. Am. Psithyrus don't mimic their victims as closely as do the European ones. This spp. has been reported as an inquiline of pensylvanicus, but it more commonly attacks Pyrobombus, although it doesn't look much like them. Some of our Psi coloration is mysterious as it doesn't seem to resemble ANY Bombus in its range, never mind the species it attacks. *sigh*

insularis is close in color to some Rocky Mt. Bombus
such as some sympatric local color forms of rufocinctus, californicus, and occidentalis.

Cuckoo bumble bee?
Interesting! This looks like either a very worn true bumble bee (Bombus sp.), or a cuckoo bumble bee (Psithyrus sp.). The characters you really need to be certain of the ID are not obvious in this image, though. I'm still betting on Psithyrus, a social parasite of Bombus.

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