The NSS Bulletin - ISSN 1090-6924
Volume 37 Number 1: 5-8 - January 1975

A publication of the National Speleological Society

Distribution and Biology of Amoebaleria defessa (Osten Sacken) and Heleomyza brachypterna (Loew) (Piptera: Heleomysidea) in an Indiana Cave
John Busacca


Four heleomyzid species, Amoebaleria defessa (Osten Sacken), Heleomyza brachypterna (Loew), Aecothea specus (aldrich) and Heleomysa serrta (Linnaeus) were found in Roy's Cave, Greene County, Indiana. Of these 4 species, the latter two composed only two to six percent of the cave heleomysid population.

The area 40 to 50 m from the cave entrance consistently contained the greatest density of flies. There was no statistically significant variance from an expected equal male/female ratio of flies.

In November, an extensive collection of flies showed that H. brachypterna was found in greatest density 30 to 80 m from the cave entrance and was not found more than 210 m from the entrance. The denstiy of A. defessa was not as great as that of H. brachypterna near the entrance of the cave, but increased gradually and reached a plateau between 120 and 210 m. A. defessa was found at a fairly uniform density, with one exception, much deeper in the cave than H. brachypterna.

Flies moved further into the cave with extremes in temperature and relative humidity outside the cave. A. defessa mighrated sooner than did H. brachypterna. In January, both heleomyzid species were found deep in the cave, with H. brachypterna being found as far as 750 m from the cave entrance.

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