Sensory systems & communication I Flashcards
Mechanoreception
an insect’s sense of touch
mechanoreception - where is it located
- Antenna
- Cerci
- All over body
mechanoreception - Antenna
- All antennae are sensitive to touch, but in some groups, they project ahead as sort of ‘feelers’ (Roach and katydid)
- Antennae are also chemo-receptors
mechanoreceptors - Cerci
- “Rear view” antennae
- Most insects don’t have cerci
mechanoreception - all over body
- Trichoid sensillum (sensilla, plural)
- Hair in socket connected to neuron. Hair can move, motion activates nerve
- Can be extremely sensitive
Proprioception
sense of body position
proprioception - where is it located
- Hair-plate sensila (touch of adjacent plate)
- Campaniform sensillum (distortion of cuticle associated with motion)
- Stretch receptors (sense stretch of membrane)
Vibrational communication
- Using vibrations through substrate or touch to communicate
- Senders produce vibrations
- Receiver detects them via mechanoreceptors
vibrational communication - examples
- Sharpshooter mating calls
- Termite
- Honeybee dance communication
vibrational communication - sharpshooter mating calls
- they use substrate vibrations on plants
- Male calls female
- Role of female dominance: female signals other females
- Works bc they are all on the plant together
vibrational communication: Termites
- Banging the nest with their head sends signal throughout, alerts other termites
- Takes place in tunnels in wood or dirt
vibrational communication - honeybee
the waggle dance conveys info about distance and direction to food source
vibrational communication - waggle dance: vertical
direction of azimuth
vibrational communication - waggle dance: azimuth
vertical line dropped down from the sun
vibrational communication - waggle dance: length
distance to food source
vibrational communication - waggle dance: How can it be a reliable signal when the sun moves throughout the day
Couple directional information with circadian clock
vibrational communication - waggle dance: What happens when it cloudy
- insects see polarization of light
- This allows insects to know there the sun is even when not visible
vibrational communication - waggle dance: How do they measure distance
optic flow = Things passing by correlate with distance
vibrational communication - What if you don’t fly, and there’s nothing around for flow?
- direction = polarized light
- distance = They ‘count’ steps
hearing
Detecting sound (vibrations through air, not substrate)
hearing - Tympanum
insect ‘ear’
hearing - how to get hearing
Attach nerves to tympanum rather than cuticle
hearing - why hear
- produce sound to call mates
- locate prey
- Avoid predatory bats
- more than one function
why hear - call mates
- For many orthoptera, cicadas, males produce sound to call mates
- use stridulation
why hear: call mates - stridulation
mechanical vibration from rubbing specialized teeth on forewings together
why hear - locate prey
Parasitoid flies of crickets have evolved hearing to locate cricket hosts
why hear - Avoid predatory bats
- bats use ultrasound to locate prey
- moth ear: neurons only fire in response to tympanal vibrations of common bat ultrasound frequencies
- Other insects too: mantis response to ultrasound is to throw out arms into an unpredictable ‘powerdive’
why hear - more than one function
Cricket and parasitoid fly example: cricket needs to use sound (not ultra) for their own communication. But use ultrasound to avoid bats
