TY  - JOUR
A1  - Scheiner, Ricarda
A1  - Toteva, Anna
A1  - Reim, Tina
A1  - Sovik, Eirik
A1  - Barron, Andrew B.
T1  - Differences in the phototaxis of pollen and nectar foraging honey bees are related to their octopamine brain titers
JF  - Frontiers in physiology
N2  - The biogenic amine octopamine is an important neuromodulator, neurohormone and neurotransmitter in insects. We here investigate the role of octopamine signaling in honey bee phototaxis. Our results show that groups of bees differ naturally in their phototaxis. Pollen forgers display a lower light responsiveness than nectar foragers. The lower phototaxis of pollen foragers coincides with higher octopamine titers in the optic lobes but is independent of octopamine receptor gene expression. Increasing octopamine brain titers reduces responsiveness to light, while tyramine application enhances phototaxis. These findings suggest an involvement of octopamine signaling in honey bee phototaxis and possibly division of labor, which is hypothesized to be based on individual differences in sensory responsiveness.
KW  - biogenic amines
KW  - tyramine
KW  - division of labor
KW  - honey bee
KW  - light responsiveness
KW  - insect
KW  - behavior
Y1  - 2014
U6  - https://doi.org/10.3389/fphys.2014.00116
SN  - 1664-042X
VL  - 5
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Jeon, Jae-Hyung
A1  - Chechkin, Aleksei V.
A1  - Metzler, Ralf
T1  - Scaled Brownian motion: a paradoxical process with a time dependent diffusivity for the description of anomalous diffusion
JF  - Physical chemistry, chemical physics : PCCP
N2  - Anomalous diffusion is frequently described by scaled Brownian motion (SBM){,} a Gaussian process with a power-law time dependent diffusion coefficient. Its mean squared displacement is ?x2(t)? [similar{,} equals] 2K(t)t with K(t) [similar{,} equals] t[small alpha]-1 for 0 < [small alpha] < 2. SBM may provide a seemingly adequate description in the case of unbounded diffusion{,} for which its probability density function coincides with that of fractional Brownian motion. Here we show that free SBM is weakly non-ergodic but does not exhibit a significant amplitude scatter of the time averaged mean squared displacement. More severely{,} we demonstrate that under confinement{,} the dynamics encoded by SBM is fundamentally different from both fractional Brownian motion and continuous time random walks. SBM is highly non-stationary and cannot provide a physical description for particles in a thermalised stationary system. Our findings have direct impact on the modelling of single particle tracking experiments{,} in particular{,} under confinement inside cellular compartments or when optical tweezers tracking methods are used.
KW  - single-particle tracking
KW  - living cells
KW  - random-walks
KW  - subdiffusion
KW  - dynamics
KW  - nonergodicity
KW  - coefficients
KW  - transport
KW  - membrane
KW  - behavior
Y1  - 2014
U6  - https://doi.org/10.1039/C4CP02019G
VL  - 30
IS  - 16
SP  - 15811
EP  - 15817
PB  - The Royal Society of Chemistry
CY  - Cambridge
ER  -