| Abstract: | Camponotus mirabilis (Hymenoptera: Formicidae) is a highly specialized resident of live Guadua bamboo in western Amazonia. Workers in established colonies open and invade young, unlignified culms, and mature polydomous colonies occupy several‐to‐many adjacent stems. Multistoried carton shelves support brood inside culms, and larvae are nourished by honeydew of coccids (Cryptostigma guadua). Constructing a system of stem holes and wicks, C. mirabilis modifies occupied stems in ways that produce passive water evacuation. Nocturnally foraging workers gather both prey and wood fiber, a component of wicks. Diurnally, they boil aggressively from agitated stems, and are attacked by parasitic phorid flies (Diptera: Phoridae). Culms housing C. mirabilis are stouter and more erect than are unoccupied stems but are opened regularly by capuchin monkeys (Cebus apella) searching for brood and perhaps reproductive castes. Damaged by monkeys, weak‐walled Guadua stems frequently collapse and are abandoned by ants. Breakdown of brood shelves leaves nutrient‐rich carton suspended in water within basal internodes, but isotopic analyses fail to show that occupied culms utilize either nitrogen from carton or carbon respired by ants or decomposing debris. Lower foliar nitrogen concentration in occupied than in control stems suggests that coccids and ants parasitize host resources. A prior experimental survey of bamboo ants may have missed C. mirabilis because females found new colonies in culms occupied by another bamboo specialist, and established colonies invade only young bamboo growth. |
