Laelapidae - Stratiolaelaps scimitus
Size: 0.82 mm
Group Guild Status
Eutroglophile Predator Common
The primary prey of Stratiolaelaps mites are thrips (Insecta: Thysanoptera), but they also feed on other soil arthropods and nematodes (Walter 2006). S. scimitus is a cosmopolitan soil-inhabiting generalist predatory mite species that has been transported around the world by humans (BMOC). The species is sold in commercial agriculture to control dark-winged fungus gnats (Diptera: Sciaridae) in greenhouse operations (Cabrera et al. 2005). Two undescribed species of Stratiolaelaps were reported from Hidden Cave in the Guadalupe Mountains of southeastern New Mexico (Polyak et al. 2001).
Stratiolaelaps mites are the dominant small predators on the fresh bat guano deposits in the cave where they likely feed on nematodes and a variety of micro-arthropods, including other mite species. One unidentified laelapid mite was observed with an entomobryid collembolan (springtail) in its chelicerae at invertebrate station 20 at Millipede Meadows.
We currently have two species of predatory Stratiolaelaps mites in the cave. Since the initial study only listed a single species of laelapid mite (identified as S. scimitus by a review of the original materials), we do not know if both Stratiolaelaps species were present at that time. S. scimitus is commonly moved around by anthropogenic means. Since the species was present at the time of the initial study, it may have arrived in the cave on its own, or been accidentally introduced by early explorers of the cave.
Interestingly there is a complete segregation of the two Stratiolaelaps species at the two major bat guano deposits in the cave. The Lunch Spot guano deposit supports only S. scimitus, and the Maternity Roost site is exclusively the undescribed Stratiolaelaps sp. These two sites are approximately 50 meters apart. Some cosmopolitan predatory invertebrates are successful because they are more aggressive than indigenous predatory species. The potential for S. scimitus to eventually colonize the Maternity Roost guano site is unknown.
© 2019 R.B. Pape. All rights reserved.