Harvestmen in Texas Cave

In July of 2001 I visited Friesenhahn Cave near San Antonio, TX with my former college classmate and friend, Larry Meissner, who then managed the cave and its use for Concordia University in Austin.

While my main interest (and Larry's) was in the Pleistocene fossils found in the bottom of the cave, I was astounded by the thousands and thousands of harvestmen that lined the walls of the cave as we climbed down a ladder apx. 45 feet to the cave floor. As we climbed down, our actions disturbed the thick masses of harvestmen that lined the walls, and basketball-sized clumps of them fell down on top of us!

Larry never had anyone ID these harvetmen. I'd like someone to "confirm" what they might be, and lead me to information about their life history. I presume (always dangerous) that they use the cave for shelter during the hot, dry day and proceed out across the landscape above ground after dark -- but would like a confirmation of that.

During a recent telephone call, Larry told me that the masses of harvestmen (and crickets) that once lined the cave walls are now gone. At the time Concordia University got the property, it came along with 3.5 acres above ground -- but was part of an 800 acre parcel -- most of which was being developed for housing. Would our assumption that the loss of the surrounding acreage where the harvestmen foraged at night be the cause of their population collapse? How far would these harvestmen forage from the cave?