TY - JOUR A1 - Chen, Jiangtian A1 - Reiher, Wencke A1 - Hermann-Luibl, Christiane A1 - Sellami, Azza A1 - Cognigni, Paola A1 - Kondo, Shu A1 - Helfrich-Förster, Charlotte A1 - Veenstra, Jan A. A1 - Wegener, Christian T1 - Allatostatin A Signalling in Drosophila Regulates Feeding and Sleep and Is Modulated by PDF JF - PLoS Genetics N2 - Feeding and sleep are fundamental behaviours with significant interconnections and cross-modulations. The circadian system and peptidergic signals are important components of this modulation, but still little is known about the mechanisms and networks by which they interact to regulate feeding and sleep. We show that specific thermogenetic activation of peptidergic Allatostatin A (AstA)-expressing PLP neurons and enteroendocrine cells reduces feeding and promotes sleep in the fruit fly Drosophila. The effects of AstA cell activation are mediated by AstA peptides with receptors homolog to galanin receptors subserving similar and apparently conserved functions in vertebrates. We further identify the PLP neurons as a downstream target of the neuropeptide pigment-dispersing factor (PDF), an output factor of the circadian clock. PLP neurons are contacted by PDF-expressing clock neurons, and express a functional PDF receptor demonstrated by cAMP imaging. Silencing of AstA signalling and continuous input to AstA cells by tethered PDF changes the sleep/activity ratio in opposite directions but does not affect rhythmicity. Taken together, our results suggest that pleiotropic AstA signalling by a distinct neuronal and enteroendocrine AstA cell subset adapts the fly to a digestive energy-saving state which can be modulated by PDF. KW - neurons KW - neuroimaging KW - circadian rhythms KW - food consumption KW - sleep KW - biological locomotion KW - Drosophila melanogaster KW - signal peptides Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178170 VL - 12 IS - 9 ER - TY - JOUR A1 - Beer, Katharina A1 - Steffan-Dewenter, Ingolf A1 - Härtel, Stephan A1 - Helfrich-Förster, Charlotte T1 - A new device for monitoring individual activity rhythms of honey bees reveals critical effects of the social environment on behavior JF - Journal of Comparative Physiology A N2 - Chronobiological studies of individual activity rhythms in social insects can be constrained by the artificial isolation of individuals from their social context. We present a new experimental set-up that simultaneously measures the temperature rhythm in a queen-less but brood raising mini colony and the walking activity rhythms of singly kept honey bees that have indirect social contact with it. Our approach enables monitoring of individual bees in the social context of a mini colony under controlled laboratory conditions. In a pilot experiment, we show that social contact with the mini colony improves the survival of monitored young individuals and affects locomotor activity patterns of young and old bees. When exposed to conflicting Zeitgebers consisting of a light-dark (LD) cycle that is phase-delayed with respect to the mini colony rhythm, rhythms of young and old bees are socially synchronized with the mini colony rhythm, whereas isolated bees synchronize to the LD cycle. We conclude that the social environment is a stronger Zeitgeber than the LD cycle and that our new experimental set-up is well suited for studying the mechanisms of social entrainment in honey bees. KW - Social entrainment KW - Foragers KW - Nurses KW - Locomotor activity KW - Temperature rhythms Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188030 VL - 202 IS - 8 ER - TY - JOUR A1 - Beer, Katharina A1 - Joschinski, Jens A1 - Sastre, Alazne Arrazola A1 - Krauss, Jochen A1 - Helfrich-Förster, Charlotte T1 - A damping circadian clock drives weak oscillations in metabolism and locomotor activity of aphids (Acyrthosiphon pisum) JF - Scientific Reports N2 - Timing seasonal events, like reproduction or diapause, is crucial for the survival of many species. Global change causes phenologies worldwide to shift, which requires a mechanistic explanation of seasonal time measurement. Day length (photoperiod) is a reliable indicator of winter arrival, but it remains unclear how exactly species measure day length. A reference for time of day could be provided by a circadian clock, by an hourglass clock, or, as some newer models suggest, by a damped circadian clock. However, damping of clock outputs has so far been rarely observed. To study putative clock outputs of Acyrthosiphon pisum aphids, we raised individual nymphs on coloured artificial diet, and measured rhythms in metabolic activity in light-dark illumination cycles of 16:08 hours (LD) and constant conditions (DD). In addition, we kept individuals in a novel monitoring setup and measured locomotor activity. We found that A. pisum is day-active in LD, potentially with a bimodal distribution. In constant darkness rhythmicity of locomotor behaviour persisted in some individuals, but patterns were mostly complex with several predominant periods. Metabolic activity, on the other hand, damped quickly. A damped circadian clock, potentially driven by multiple oscillator populations, is the most likely explanation of our results. KW - circadian mechanisms KW - behavioural ecology KW - damped circadian clock KW - Acyrthosiphon pisum Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170020 VL - 7 IS - 14906 ER -