TY - JOUR
T1 - The role of anchor-tipped larval hairs in the organization of ant colonies
AU - Penick, Clint
AU - Copple, R. Neale
AU - Mendez, Raymond A.
AU - Smith, Adrian A.
N1 - Funding Information:
We would like to thank Bert Hölldobler for providing access to colonies of P. rhea, Kevin Haight for help maintaining colonies in the laboratory, Si Phrasavath for assistance with SEM imaging at the LeRoy Eyring Center for Solid State Science, and Rick Overson for help during field collections. A portion of this work was conducted during a field course organized and supported by the School of Life Sciences at ASU and the Smithsonian Tropical Research Institute. Colonies of P. rhea were donated by Randy Morgan of the Cincinnati Zoo & Botanical Garden and Paige Howarth of the San Diego Zoo.
PY - 2012/7/25
Y1 - 2012/7/25
N2 - The spatial organization within a social insect colony is a key component of colony life. It influences individual interaction rates, resource distribution, and division of labor within the nest. Yet studies of social insect behavior are most often carried out in artificial constructions, which may change worker behavior and colony organization. We observed how workers of the ant Pheidole rhea organized brood in nests with deep chambers and textured walls that were designed to mimic their natural constructions more closely. Instead of clumping larvae into piles on the chamber floor, workers suspended fourth-instar larvae from the vertical walls and ceiling of each chamber while young larvae and pupae were clumped at the base. Fourth-instar larvae possess five rows of anchor-tipped hairs on their dorsal side, and we predicted that these hairs functioned to attach larvae to the nest walls. We gave larvae "haircuts," where only the anchor-tipped hairs were removed, and then tested their ability to adhere to a textured surface raised to an angle of 90° and then 120° with respect to the horizontal plane. Larvae whose hairs had been clipped came unattached in almost all trials, while larvae whose hairs remained intact stayed attached. This confirmed that anchor-tipped hairs functioned to attach larvae to the walls of the nest. The presence of anchor-tipped hairs is widespread and has been documented in at least 22 genera from the ant subfamily Myrmicinae, including species that occur in a variety of environments and represent a broad range of nesting habits. Based on our results, it is likely that many species exhibit this larval hanging behavior, and this could impact colony characteristics such as spatial organization and the care of developing larvae by nurse workers.
AB - The spatial organization within a social insect colony is a key component of colony life. It influences individual interaction rates, resource distribution, and division of labor within the nest. Yet studies of social insect behavior are most often carried out in artificial constructions, which may change worker behavior and colony organization. We observed how workers of the ant Pheidole rhea organized brood in nests with deep chambers and textured walls that were designed to mimic their natural constructions more closely. Instead of clumping larvae into piles on the chamber floor, workers suspended fourth-instar larvae from the vertical walls and ceiling of each chamber while young larvae and pupae were clumped at the base. Fourth-instar larvae possess five rows of anchor-tipped hairs on their dorsal side, and we predicted that these hairs functioned to attach larvae to the nest walls. We gave larvae "haircuts," where only the anchor-tipped hairs were removed, and then tested their ability to adhere to a textured surface raised to an angle of 90° and then 120° with respect to the horizontal plane. Larvae whose hairs had been clipped came unattached in almost all trials, while larvae whose hairs remained intact stayed attached. This confirmed that anchor-tipped hairs functioned to attach larvae to the walls of the nest. The presence of anchor-tipped hairs is widespread and has been documented in at least 22 genera from the ant subfamily Myrmicinae, including species that occur in a variety of environments and represent a broad range of nesting habits. Based on our results, it is likely that many species exhibit this larval hanging behavior, and this could impact colony characteristics such as spatial organization and the care of developing larvae by nurse workers.
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U2 - 10.1371/journal.pone.0041595
DO - 10.1371/journal.pone.0041595
M3 - Article
C2 - 22848539
AN - SCOPUS:84864341794
SN - 1932-6203
VL - 7
JO - PloS one
JF - PloS one
IS - 7
M1 - e41595
ER -