Biology and ecology of a deep cave nesting spider wasp, Ageniella evansi Townes, 1957 (Hymenoptera: Pompilidae), in Arizona

Abstract

Cavernicolous populations of the spider wasp Ageniella evansi Townes, 1957 (Hymenoptera: Pompilidae) nest deep within limestone caves at Colossal Cave Mountain Park near Tucson, Arizona, USA. These remarkable populations are the only truly cavernicolous pompilid wasps currently known. As many as 79 females were documented nesting simultaneously within Arkenstone Cave. The facts that the wasps do not nest near cave entrances but only deep within the interior of the caves, are philopatric to each occupied cave and have been present each year for decades, confirm their cavernicolous behavior as subtroglophiles. Studies conducted for over 30 years revealed many insights into the behavior of these wasps in addition to their nesting deep within limestone caves, including: intraspecific and interspecific competition, plasticity in host selection, precision solar navigation, evidence that some form of communal nesting may be present and behavior suggestive of rudimentary cognition in the species. This study demonstrates the importance of assessing all animals found in caves as potential ecological elements and not focusing solely on exotic troglobiotic species.