Daniel Robert extra reading Flashcards
Clarke et al 2013
Measured charge when bumble bees landed on Petunia integrifolia, recorded positive changes in potential in stem when bees land on flower.
average change lasted 100s, and often initiated before bee contact.
Bee training experiment - E flowers at 30V sucrose reward. identical 0V with quinine. measured learning comparing to random choice model. 81% accuracy. After flowers grounded, 54% accuracy - no discrimination.
Sutton et al 2016
Antennae and mechanosensory hairs sense electric fields. Hair deflection elicit neural activity.
greater deflection when more charge carried by bee.
Ampullae of lorenzini have same electrical potential as surrounding water. Change btw jelly and inside of animal transduced by epithelial cells., causing neural excitation/inhibition.
honey bees antennae deflect in response to electric fields produced in a waggle dance.
Lohmann et al 1995
Panulirus argus - spiny lobster
annual migration crawling seaward in single file line. orientate in a straight line back to den at the end of the day, even in darkness
UW coils to alter magnetic field, eye caps on lobsters, each only tested once.
Orientation arena 1.52m square. ‘established’ course when unchanged for 5 mins. 3 controls - Within horizontal coil, off. within vertical coil, off. within horizontal coil, on.
lobsters exposed to either reversal of horizontal or vertical component or control. Only reveral in horizontal ambient field changed direction.
suggetss lobster compass based on field polarity and differs from inclination compass such as birds and turtles.
Apposition eyes image formation
Each facet produces inverted image. some species resolve inversion, or just use many images to indicate average intensity across field of view.
inverted image focused onto distal tip of rhabdom.
Rhabdom acts as a light guide as it has higher refractive index than surroundings.
angle between rhabdomeres is identical to angle between ommatidia - twist in axon bundle to prevent single point being viewed 7 times.
axons looking at same point all connect with the same point in lamina so only one image produced, but 7x stronger photon capture than superposition (neural superposition).
Bee microvilli arrangement
Bees microvilli in rhabdom arranged in orthogonal sets (right angles) to distinguish polarised light.
special region dedicated to detecting pol, and rest of eye has twisted microvilli so it doesnt interfere with colour vision.
mechanisms of temporary light adaptation
- iris cuts out outer six rhabdomeres in light and shrinks to open them in dark
- pigment granules migrate to region most central to rhabdom in light and withdraw in dark.
- dimensions of rhabdom change, may involve resynthesis of membranes. 4. movements of rhabdom away or to lens.
why are there more receptors at the front of insect eyes than at the side? top?
- Velocity flow field – objects move backwards across the eye as animal moves forwards.
Objects at side move faster than those in front so likely to blur, economical to have less receptors there.
Upwards pointing section can be acute region for sexual comp, or if both sexes have it, likely for predation.
Narendra et al 2016
study of light and dark adaptation in eyes of diurnal, crepuscular and nocturnal forager ants.
All have variable primary pigment cell pupil - constricts the crystalline cone in bright light to control for light flux.
Nocturnal M. pyriformis - constriction islight dependent, whereas opening aperture is regulated by endogeneous rhythm.
All species: retinular cell pigment granules radially migrate towards the rhabdom, driven by light intensity.
crepuscular and nocturnal ants not restricted by visual system to niche but day ants require high light intensity to operate.
Greggers et al 2013
Honey bee waggle dance is communication using electric fields indicating whereabouts of food source in relation to angle of the sun.
Compared electrical recordings to video clips of dancing bees showed the sequence of wing beats and abdomen movements generates a modulated electric field of pulses of 100s of volts.
Tethers bees and exposed to either constant or modulated electric fields mimicking waggle dancer. Triggered antennal mvts and walking, showing electric cues evoke beh response.
Menzel 2012
harnessed honey bees trained to associate with charged rewarded flower or uncharged quinine flower.
Bees with antennae removed/covered in wax couldn’t tell difference
