title: Responses of the antennal bimodal hygroreceptor neurons to innocuous and noxious high temperatures in the carabid beetle, Pterostichus oblongopunctatus.
abstract: Electrophysiological responses of thermo- and hygroreceptor neurons from antennal dome-shaped sensilla of the carabid beetle Pterostichus oblongopunctatus to different levels of steady temperature ranging from 20 to 35°C and rapid step-changes in it were measured and analysed at both constant relative and absolute ambient air humidity conditions. It appeared that both hygroreceptor neurons respond to temperature which means that they are bimodal. For the first time in arthropods, the ability of antennal dry and moist neurons to produce high temperature induced spike bursts is documented. Burstiness of the spike trains is temperature dependent and increases with temperature increase. Threshold temperatures at which the two neurons switch from regular spiking to spike bursting are lower compared to that of the cold neuron, differ and approximately coincide with the upper limit of preferred temperatures of the species. We emphasise that, in contrast to various sensory systems studied, the hygroreceptor neurons of P. oblongopunctatus have stable and continuous burst trains, no temporal information is encoded in the timing of the bursts. We hypothesise that temperature dependent spike bursts produced by the antennal thermo- and hygroreceptor neurons may be responsible for detection of noxious high temperatures important in behavioural thermoregulation of carabid beetles.
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia. Electronic address: karin.nurme@emu.ee.
authors.forename: Karin
authors.initials: K
authors.lastname: Nurme
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia.
authors.forename: Enno
authors.initials: E
authors.lastname: Merivee
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia.
authors.forename: Anne
authors.initials: A
authors.lastname: Must
authors.affiliation: Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia.
authors.forename: Ivar
authors.initials: I
authors.lastname: Sibul
authors.affiliation: Department of Science, University of Roma Tre, Viale G. Marconi 446, I-00146 Rome, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Muzzi
authors.affiliation: Department of Science, University of Roma Tre, Viale G. Marconi 446, I-00146 Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Di Giulio
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Williams
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi Street 1, 51014 Tartu, Estonia.
authors.forename: Ene
authors.initials: E
authors.lastname: Tooming
mesh_terms: D000818:Animals; D057506:Arthropod Antennae / Q000502:physiology; D001517:Coleoptera / Q000502:physiology*; D055724:Electrophysiological Phenomena; D006358:Hot Temperature; D006813:Humidity; D058618:Sensilla / Q000502:physiology*; D011984:Sensory Receptor Cells / Q000502:physiology*
keywords: Behavioural thermoregulation; Dome-shaped sensilla; Electrophysiology; FIB/SEM technique; Inner structure; Peripheral spike bursting