Tachinidae - undet. sp.
Undet. genus and sp.
Size: Approximately 6.5 mm
Group Guild Status
Trogloxene Parasite Rare
This species is documented from a single empty pupal case found in the far west end of Granite Dells on August 28, 2012. The pupal case is from some species of calyptrate muscoid fly. As far as we know none of the three surface connections in Granite Dells are large enough to admit vertebrates to the cave. Therefore, vertebrates that might wander or fall into cave entrances and die would not be present to attract muscoid flies such as blow flies (family Calliphoridae) to the cave. Without this potential, the only logical explanation for the presence of this pupal case is the presence of a known internal parasite of cave crickets. I (RBP) have observed these pupal cases on cave floors and larvae of the flies extruded from their digestive tract in two other caves in southern Arizona. The species is almost certainly a tachinid fly, but the species (or species) is/are currently not known. The pupal cases are very persistent in caves, potentially lasting for many years. The presence of only a single pupal case indicates that this parasitic species is likely rare in the Kartchner Caverns area.
The cave crickets probably ingest the eggs or larvae of the flies while foraging on vegetation outside of the cave. Alternatively, the flies may actively lay their eggs or larvae directly on the crickets when they are outside of the cave.
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