title: Measuring individual locomotor rhythms in honey bees, paper wasps and other similar-sized insects.
abstract: Circadian rhythms in social insects are highly plastic and are modulated by multiple factors. In addition, complex behaviors such as sun-compass orientation and time learning are clearly regulated by the circadian system in these organisms. Despite these unique features of social insect clocks, the mechanisms as well as the functional and evolutionary relevance of these traits remain largely unknown. Here we show a modification of the Drosophila activity monitoring (DAM) system that allowed us to measure locomotor rhythms of the honey bee, Apis mellifera (three variants; gAHB, carnica and caucasica), and two paper wasps (Polistes crinitus and Mischocyttarus phthisicus). A side-by-side comparison of the endogenous period under constant darkness (free-running period) led us to the realization that these social insects exhibit significant deviations from the Earth's 24 h rotational period as well as a large degree of inter-individual variation compared with Drosophila. Experiments at different temperatures, using honey bees as a model, revealed that testing the endogenous rhythm at 35°C, which is the hive's core temperature, results in average periods closer to 24 h compared with 25°C (23.8 h at 35°C versus 22.7 h at 25°C). This finding suggests that the degree of tuning of circadian temperature compensation varies among different organisms. We expect that the commercial availability, cost-effectiveness and integrated nature of this monitoring system will facilitate the growth of the circadian field in these social insects and catalyze our understanding of the mechanisms as well as the functional and evolutionary relevance of circadian rhythms.
authors.affiliation: Department of Biology, University of Puerto Rico, POB 23360, San Juan 00931, Puerto Rico.
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Giannoni-Guzmán
authors.forename: Arian
authors.initials: A
authors.lastname: Avalos
authors.forename: Jaime
authors.initials: J
authors.lastname: Marrero Perez
authors.forename: Eduardo J
authors.initials: EJ
authors.lastname: Otero Loperena
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kayım
authors.forename: Jose Alejandro
authors.initials: JA
authors.lastname: Medina
authors.forename: Steve E
authors.initials: SE
authors.lastname: Massey
authors.forename: Meral
authors.initials: M
authors.lastname: Kence
authors.forename: Aykut
authors.initials: A
authors.lastname: Kence
authors.forename: Tugrul
authors.initials: T
authors.lastname: Giray
authors.forename: José L
authors.initials: JL
authors.lastname: Agosto-Rivera
mesh_terms: D000818:Animals; D001516:Bees / Q000235:genetics / Q000502:physiology*; D002940:Circadian Rhythm; D005260:Female; D009043:Motor Activity; D013045:Species Specificity; D013696:Temperature; D014863:Wasps / Q000502:physiology*
keywords: Apis mellifera; Circadian rhythms; Honey bees; Locomotor activity; Mischocyttarus; Polistes; Temperature compensation; Wasps