Pests, Plagues & Politics
Lecture 13
Insect Communication: Light and Sound Shows
Key Points:
Insect Communication: Light and Sound Shows
• Bioluminescence
– Which orders use it?
– How do they use it?
• Sound Communication
– Which order is best known for “singing”
– Functions of acoustic behavior
– Mechanisms for sound production
– Temporal separation
http://www.youtube.com/watch?v=PnxkCX3tX1Q
Communication with LIGHT
• Fireflies & Glow-worms
• Misnomer
– neither Fire, nor are they Flies (well, sometimes they are)
• Coleoptera (Beetles)
– families
• Lampyridae
• Phengodidae
• Utilize bioluminescence
for sexual communication.
http://beneficialbugs.org/bugs/Firefly/boreal_firefly.htm
Communication with LIGHT
• Bioluminescence
– Nearly 100% of a firefy’s light is given off as light
– Compare this to an incandescent light bulb, which gives off
10% light and 90% heat
• The chemical reaction:
– Understanding this chemistry led to the making of glowsticks!
Fireflies
• Wonderful scientific names such as:
– Photuris
• “tail light” (photos = light - ouron = tail)
– Photinus
• “a little tail light” (diminutive form)
Fireflies
• Courtship Signals
– Flash patterns are species specific
– Normally females (on the ground) signaling for
flying males.
– Females frequently wingless or even
“larviform” as adults.
Female Photinus bromleyi
The Mating Game
Fireflies
• Synchronous-Aggregate
Flashers
– S.E. Asia
Glow-Worms
• Some are beetles - some are flies
– ergo, the confusion of common names.
Glow-Worm (a fly)
Arachnocampa luminosa - A fungus gnat from New Zealand
Glow-Worms
Larvae create sticky mucous strings and light them up with their
glowing tails to lure and trap other insects!
Glow-worm (a beetle)
Phengodes sp. larva, Maryland
Frequently asked question
• Why are there no fireflies in Oregon??
• ANSWER: There ARE fireflies in Oregon!
Zarhipis integripennis
Pterotus obscuripennis
Oregon Glow-worms
• Two beetle species in two different families
– Zarhipis integripennis (Phengodidae)
• a predator of millipedes
• light from each body segment
– Pterotus obscuripennis (Lampyridae)
• a predator of snails
• light from terminal body segment
– Bioluminescence from embryo-larvalarviform adult females (males do not
“glow”)
Communication with Sound
• “A great many insect species produce sound by
means of special structures, but only a few, such
as crickets, grasshoppers & cicadas, are heard by
most people”
– Borror & DeLong
• The ORTHOPTERA
– others: Coleoptera, Hymenoptera, Isoptera,
Homoptera & Lepidoptera
Functions of Acoustic Behavior
• REPRODUCTION
– primarily for mate attraction &/or territorial
display (much like birds)
• REPELLENCY
– Passalid beetles; hissing cockroach, et alia
• DEFENSE ALARMS
– termites, et alia
Functions of Acoustic Behavior
• FOOD GATHERING
– Phonotaxis by parasitoids & predators
– Female flies of the genus Ormia must find a specific cricket
host on which to deposit their parasitic maggots. To
reproduce, female flies must perform the same task as
female crickets - to find a singing male cricket.
– has led to the “development” of
smart, silent, satellite male
crickets.
Mechanisms for sound production
• STRIDULATION
– the rubbing of one body part against another
• grasshoppers, beetles, ad infinitum
• THE most common insect musical “instrument”
• VIBRATION
– of special membranes known as TYMBALS
• cicadas, some leafhoppers, some moths
– of wings or thorax
• incidental sounds from many, many species.
Chirp Chirp!
• Only the males chirp
– There are special songs
for courtship, fighting
and sounding an alarm
• Sense sound using
tympani (hearing organs)
in their front legs
• Want to know the temp.?
– Chirps/15 sec. + 40.
Mechanisms for sound production
• STRIKING against a substrate
– alarm calls of damp wood termites
• EJECTION of air
– death head moth, hissing cockroach
The most noted “singers”
• The Orthopterans
– grasshoppers - crickets - katydids
– Stridulation is the primary mechanism
– Two Song Types
• “Calling” songs by males for females
• “Fighting” songs by males for territorial defense
Temporal Song Separation
• Night Singers
– nearly all katydids
• Day Singers
– most grasshoppers
• Day &/or Night Singers
– most crickets
Chorus Singers
• Cone-headed grasshoppers & tree crickets
– More than two individuals
singing simultaneously, with
their sound pulses
synchronized or alternating.
Neoconocephalus retusus
Cone headed grasshopper
Gryllodes sigillatis
Tropical House Cricket
Gryllus fultoni
Southern Wood Cricket
Oecanthus pini
Pine Tree Cricket
Neoxabea bipunctata
Two spotted tree cricket
Pictonemobius hubbelli
Hubbell’s Ground Cricket
Tidewater meadow cricket
Conocephalus nigropleuroides
Conocephalus fasciatus
Slender Meadow Katydid
Orchelimum silvaticum
Long-spurred Meadow Katydid
Orchelimum vulgare
Common Meadow Katydid
Palmetto Conehead
Belocephalus sabalis
Key Points:
Insect Communication: Light and Sound Shows
• Bioluminescence
– Which orders use it?
– How do they use it?
• Sound Communication
– Which order is best known for “singing”
– Functions of acoustic behavior
– Mechanisms for sound production
– Temporal separation
Cicadas en masse, Princeton, 2004