title: Pea Aphids (Hemiptera: Aphididae) Have Diurnal Rhythms When Raised Independently of a Host Plant.
abstract: Seasonal timing is assumed to involve the circadian clock, an endogenous mechanism to track time and measure day length. Some debate persists, however, and aphids were among the first organisms for which circadian clock involvement was questioned. Inferences about links to phenology are problematic, as the clock itself is little investigated in aphids. For instance, it is unknown whether aphids possess diurnal rhythms at all. Possibly, the close interaction with host plants prevents independent measurements of rhythmicity. We reared the pea aphid Acyrthosiphon pisum(Harris) on an artificial diet, and recorded survival, moulting, and honeydew excretion. Despite their plant-dependent life style, aphids were independently rhythmic under light-dark conditions. This first demonstration of diurnal aphid rhythms shows that aphids do not simply track the host plant's rhythmicity.
authors.affiliation: Department of Animal Ecology and Tropical Biology, Biocentre, University of Würzburg, D-97074 Würzburg, Germany (Jens.Joschinski@uni-wuerzburg.de; j.krauss@uni-wuerzburg.de), Jens.Joschinski@uni- wuerzburg.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Joschinski
authors.affiliation: Neurobiology and Genetics, Biocentre, University of Würzburg, D-97074 Würzburg, Germany (Katharina. Beer@uni-wuerzburg.de; charlotte.foerster@biozentrum.uni-wuerzburg.de).
authors.forename: Katharina
authors.initials: K
authors.lastname: Beer
authors.affiliation: Neurobiology and Genetics, Biocentre, University of Würzburg, D-97074 Würzburg, Germany (Katharina. Beer@uni-wuerzburg.de; charlotte.foerster@biozentrum.uni-wuerzburg.de).
authors.forename: Charlotte
authors.initials: C
authors.lastname: Helfrich-Förster
authors.affiliation: Department of Animal Ecology and Tropical Biology, Biocentre, University of Würzburg, D-97074 Würzburg, Germany (Jens.Joschinski@uni-wuerzburg.de; j.krauss@uni-wuerzburg.de).
authors.forename: Jochen
authors.initials: J
authors.lastname: Krauss
mesh_terms: D000821:Animal Feed; D000818:Animals; D001042:Aphids / Q000502:physiology*; D057906:Circadian Clocks / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D004032:Diet; D012098:Reproduction / Q000502:physiology; D012100:Reproduction, Asexual / Q000502:physiology
keywords: Acyrthosiphon pisum; artificial diet; circadian clock; hourglass clock; photoperiodism