Oriented Behavior 1) Spend 4 hours normally devoted to writing - PDF document

Sensory Guidance W41 and Oriented Behavior 1) Spend 4 hours normally devoted to writing assignment on your Wikipedia project 2) Put your notes and outlines and sources down in outline form as far as you have y progressed 3) Print and hand in class Monday Lecture 40 4) Your assignment grade (0-10) will be based BioNB4240 on subjective estimate of progress made so far. 1 2 Examples of Oriented Behavior Sensory Guidance and Oriented Behavior How organisms respond to external stimuli: • Chemotaxis – ORIENTATION: turning response, or oriented • Chemical trail following response guided by stimulus location or • Directional tactile sense direction. • Sensing compass directions • Sensing compass directions – RESPONSE SELECTION: choice of response RESPONSE SELECTION: choice of response behavior as appropriate to stimulus. • Using landmarks and memory – Nearly every behavior has a component to it that involves orientation. 3 4 Collective behavior of bacteria How do organisms sense the direction of a stimulus? around a food source by measure of by detecting the stimulus incident direction gradient with of the stimulus two using an array of simultaneous detectors sensors by comparing two sensors with a single sensor compared successively in by successive time. comparison of a single comparison in time 5 6 1

Bacterial Chemotaxis Taxes Orientation relative to a stimulus direction Phototaxis: orientation toward the light Negative phototaxis: orientation away from the light no attractant attractant cell tumbles cell runs orientation of a planaria primitive photoreceptors provides some directional cue 7 8 Olfactory orientation to prey by a snake Trail following in an ant normal trail following Snake ( Vipera aspis) path of head movements tracks the pathway left by a mouse, recently dead by snake bite, recently dead by snake bite which has been dragged one antenna, one removed. across the 1x1 m arena. Dotted line: path of live mouse. Circle (hiding place of mouse). antennae crossed 9 10 Paramecium has a directional Pheromone Sensing in Moths tactile sense paramecium avoids contact by reversing direction of swimming 11 12 2

Electrophysiology of Orientation to Paramecium Vibration Sources microelectrode recording anterior stimulation posterior stimulation anterior: depolarize Ca ++ posterior: hyperpolarize K + 13 14 From studies by R. Eckert Using the sun to orient flight Jaques Loeb’s Model for Taxes the sun is used as the ‘landmark’ informing dance is performed in the hive food is located at a distance from hive the direction of the dance corresponds Loeb (1918) Mechanistic approach to animal orientation: taxes and kineses. to the direction of food relative to that of the sun. Gravity is substituted Applies to numerous cases of sensory guidance: light, heat, odor, sound, reference. gravity, electroreception. 15 16 Orientation in Digger Wasps Special Senses (Tinbergen and Kruyt, 1938) Insect eye: sensitive to polarized light. Pigment molecules are embedded in membrane at random. membrane at random Membranes are organized into structured microvilli. Orientation of pigment in rhabdome now has a Digger wasp leaves nest and Female returns to provide food. Pine preferred alignment circles opening for 6 second. Pine cones have been moved. relative edge of cones are placed there during microvilli. time when she is belowground Thus, behavior is guided by learning. Senses polarized light. 17 18 3

Vertebrate Rod R. Wehner polarized light sensitive area of honey bee is essential to orientation to the sun’s compass. Ommatidia in dorsal POL are sensitive to UV light. The rhabdom does not twist in this area (so the plane of the microvilli are aligned only in one direction) area retain polarization sensitivity. Other areas: twist destroys polarization sensitivity 19 20 Orientation in the desert ant, Land and Collett (1974): Visual chasing in flies Cataglyphis bicolor A classic paper in neuroethology. Use of sun depends upon polarized light sensitivity in UV. Demonstrates visual guidance is controlled by Eye is organized to match the angular position of target, angular position of target pattern of sky polarization Ant pattern of sky polarization. Ant and by angular velocity of gets intensity readout which is target across the retina. directionally sensitive. Demonstrates that males have “fovea” dorsal region of high velocity and temporal resolution. 21 22 How do electric fish locate sources? 23 24 4

25 26 Schluger and Hopkins (1986) Schluger and Hopkins (1986) 5