Paul - How Insects Sense Gravity and Odours Flashcards
Explain how bees use gravity to inform
nestmates about the location of food sources.
They go out and find food then come back to the nest to performa waggle dance that conveys information about distance and direction of the food source.The angle that the bee dances.
Honey bees perform their waggle dance on a vertical surface inside the hive, typically on the honeycomb. This vertical orientation is crucial for using gravity as a reference. T
he angle of the waggle run relative to gravity conveys directional information about the food source:
A waggle run straight up indicates the food source is in the direction of the sun
A run straight down indicates the opposite direction from the sun
Angles in between correspond to directions relative to the sun’s position
Explain the function of sensory organs.
To convert a sensory stimulus to an electrical signal in the nervous system (sensory transduction)
Using: A sensory organ, an accessory structure, a receptor cell, and a receptor.
Explain the general principles of sensory
transduction and sort its sequential processes.
What are the 2 strategies for estimating direction of gravitational forces?
- Integrating the direction of gravitational
forces measured across the whole body: Force measured by all joints. Proprioreceptors measure tension on joints. (feel arms fall down, information used by nervous system to know this) - Measuring acceleration at a single point:
The vestibular measures gravitational forces
at a single point. (inner ear)
Explain the function of the Prosternal organ in insects.
The prosternal organ is the neck organ. It measures the angle of the head relative to the to the body. On a vertical surface the bees head acts like a pendulum
Facing upwards - mouthparts fall toward ventral part of the thorax, ventral bristles stimulated
Facing downwards - mouthparts fall away from the ventral part of the thorax, dorsal bristles stimulated.
Each bristle contains a mechanosensitive neuron.
When a bristle bends, mechanically gated channels in these neurons open.
The opening of these channels alters the neuron’s membrane potential, signaling the insect that it is facing upwards or downwards.
What is the accessory structure, receptor cell, and receptor for the prosternal organ?
Accessory structure - Head, bristles
Receptor cell - Mechanoreceptor cell
Receptor - Mechanically gated channel
What does an accessory structure do?
Modifies the energy before it reaches a receptor.
Determines the modality of a sensory system.
What does a mechanoreceptor cell do?
Converts receptor activation into an electrical response
What does a receptor do?
Detects and transduces stimulus energy
What is the ultimate and proximate causes of “Drosophila flies are attracted to rotten fruit”
Why? (ultimate cause)
* Drosophila feed on fermenting fruit and lay their eggs on it
How? (proximate cause)
* Fermenting fruit emits ethanol.
* Drosophila smells ethanol.
* Drosophila displays chemotaxis towards ethanol.
What is the accessory structure, receptor cell, and receptor for insect antennae?
Accessory structure - Lipid layer on sensilla attracts lipophilic odorants
Receptor cell - Olfactory receptor neurons
Receptor - Olfactory receptor
Describe the first TWO steps involved in the sensory
transduction of olfactory stimuli.
Odorants bind to olfactory receptors, thereby changing the membrane potential of the olfactory receptor neuron.
