INSECT CALLS
Insect calls are sound signals produced by insects to communicate with others of their
species. These calls serve various purposes, such as attracting mates, defending territory,
deterring rivals, or coordinating group behavior. Mating or calling songs are the most
common, used by males to draw in receptive females, often with species-specific rhythms
or frequencies. Courtship songs, usually softer or more complex, are produced when a
potential mate is nearby to increase chances of copulation. Agonistic or rivalry calls are
aggressive signals meant to warn off competing males, while alarm or distress calls may
signal danger to nearby individuals. These sounds are produced using methods like
stridulation (rubbing body parts), percussion, or vibrating membranes, and their intensity
or rhythm may vary with environmental conditions like temperature.
1. Tiger Moth
Tiger moth.mp4
● Tiger moths belong to the subfamily Arctiinae within the family Erebidae and are
known for their bright, warning coloration.
● They are found globally, with the highest species diversity in tropical areas such
as Central and South America.
● Their colorful patterns serve as visual warnings to predators, indicating that they
are toxic or unpalatable.
● Tiger moths produce ultrasonic clicks using tymbals—specialized structures on
their thorax.
● These clicks are in a frequency range inaudible to humans but easily detected by
bats, their primary predators.
● The sounds act as acoustic warning signals, telling bats to avoid them due to their
bad taste or toxicity.
● Many tiger moths ingest toxic compounds from their larval host plants,
reinforcing the warning with real chemical defense.
● Bats can learn to associate the ultrasonic clicks with negative experiences and
avoid clicking moths in the future.
● Some species, like Bertholdia trigona, produce high-frequency click bursts (up to
4,500 clicks/sec) that jam bat sonar.
● This sonar jamming confuses bats and disrupts their ability to locate the moth,
making it a highly effective defense.
2. Field Cricket
Field cricket.mp4
Gryllus campestris (the field or European cricket) belongs to the Gryllidae family within
the Orthoptera order. In contrast to very social bees, these crickets predominantly live
alone in grasslands, hedgerows, and somewhat disturbed soils throughout Europe. Males
dig shallow burrows or sit on low plants to emit their calls, depending solely on sound to
lure mates and protect their territory.
Structure of Sound Generation
● Forewing File and Scraper: Every male possesses a “file” (a line of 100–200 tiny
teeth) on the bottom of one tegmen (forewing) and a solid “scraper” edge on the
other tegmen.
● Resonating Mirror: A delicate, membrane-like area on the wing functions as a
drumhead, enhancing sound.
● Males produce the distinct chirp by moving their wings up and down in a lateral
arc, rubbing the scraper against the file (stridulation).
Main Types of Calls
Calling song
● Pattern: An ongoing sequence of 4–7 syllables for each chirp, each syllable
lasting approximately 20–30 ms, with a space between chirps of 200–300 ms.
● Function: Extended-range signaling to receptive females; emitted most vigorously
at twilight and for several hours after dark.
● Temperature Sensitivity: The pulse rate rises by approximately 0.5 chirps/°C
(according to Dolbear's law), enabling females to gauge the surrounding
temperature based on call pattern.
Courtship Melody
● Format: Milder, brief chirp sequences (2–4 syllables) featuring uneven intervals
and sporadic wing vibrations.
● Function: When a female nears the burrow entrance or perch, the male transitions
to this softer song to lead her to his spermatophore.
Aggression or Competition Tune
● Formation: Quick flashes of 1–3 noisy syllables interspersed with brief pauses
(<100 ms), occasionally paired with forward lunging stances.
● Function: Show to nearby males to indicate presence at calling sites and
discourage intruders.
3. Asian Giant Hornet
Asian Giant Hornet.mp4
● Vespa mandarinia, commonly known as the Asian giant hornet, is the largest
hornet species in the world.
● It is native to temperate and tropical regions of Asia, including Japan, China,
Korea, Taiwan, northeastern India, Nepal, and the Russian Far East.
● These hornets typically nest in low ground cavities such as abandoned rodent
burrows or rotting tree roots, unlike other wasps that prefer higher spots.
● The buzzing sound is produced by rapid wing movement during flight, made
possible by their large body and strong flight muscles.
● Their buzz is low and deep, distinct from the higher-pitched hum of bees or
smaller wasps.
● Scientists can use differences in wingbeat frequency, pitch, and rhythm to
identify insect species by sound.
● The buzzing isn't just a flight sound—it also plays a role during foraging and
predatory behavior.
● Hornets will hover near a honeybee hive, emitting a loud buzz that can cause
alarm and panic in bees even before an attack.
● In group raids, Asian giant hornets can destroy entire bee colonies within hours,
killing adult bees and carrying away the brood to feed their larvae.
● The buzzing sound is often an acoustic signal that precedes a deadly raid,
making it both a functional flight noise and an intimidating warning to prey.
4. Clicking Beetle
Click Beetle (Elateridae) Demonstrating Click Mechanism
● The click beetle Ampedus nigricollis belongs to the family Elateridae, commonly
known as click beetles due to their distinctive sound-producing ability.
● This species is part of the larger genus Ampedus, which contains 461 recognized
species globally.
● Ampedus nigricollis is found primarily in the Holarctic region, with a range that
includes North America, Europe, and Asia.
● These beetles are typically found in forests, under bark, decaying wood, or leaf
litter, where their larvae (wireworms) develop.
● Their body is elongated and somewhat flattened, with a hard exoskeleton that
helps with their signature clicking motion.
● When threatened, these beetles perform a rapid flexing movement using a spine
on the underside of the thorax, producing a loud click sound.
● This click not only startles predators but also helps the beetle flip into the
air—useful for escaping or righting itself if flipped on its back.
● The clicking mechanism is unique to the Elateridae family and serves both a
defensive and locomotive function.
● The sound is mechanical and comes from a quick release of built-up tension as the
spine snaps into a notch, creating an audible “click.”
● This defense behavior is so characteristic that it has become a key diagnostic
trait for identifying beetles within this family in both field and lab settings.
5. Scarlet Cicada:
Rare: Orange Coloured Cicada belts out mating call from tree trunk - Brood XI in I…
Huechys sanguinea (the Scarlet Cicada) belongs to the Cicadidae family within the
Hemiptera order. Unlike social insects such as bees or ants, these cicadas are solitary and
emerge seasonally in forested and hilly regions of South and Southeast Asia. Adults are
known for their striking red-and-black coloration, which serves as a warning signal to
predators. Males are frequently seen perched on tree trunks or branches during the mating
season, producing loud and continuous calls to attract females.
Structure of Sound Generation
Tymbals: Males possess a pair of ribbed, membrane-like structures called tymbals,
located on either side of the first abdominal segment. These tymbals buckle inward when
specialized muscles contract and snap back when the muscles relax, producing a series of
sharp clicks.
Resonating Abdomen: The largely hollow abdomen acts as a resonating chamber that
amplifies the tymbal clicks into a continuous, high-pitched trill. This structure makes
cicadas among the loudest insects on Earth.
Mechanism: Rapid, repeated muscle contractions allow the male to buckle the tymbals at
frequencies exceeding 100 times per second, creating the distinctive buzzing or droning
call characteristic of cicadas.
Main Types of Calls
Calling Song
● Pattern: A sustained, high-pitched trill composed of rapid clicks delivered in a
continuous stream, often lasting several seconds to minutes.
● Function: Long-range advertisement to attract females during the mating season;
typically performed during the hottest parts of the day.
● Species Recognition: The specific frequency and pulse rate help females
distinguish conspecific males from those of other cicada species.
Courtship Melody
● Format: A softer, modulated version of the calling song with brief pauses or
irregular pulses; may include subtle changes in pitch or rhythm.
● Function: Emitted when a female approaches; thought to maintain her attention
and guide her to the male for mating.
Aggression or Rivalry Signal
● Formation: Abrupt bursts of sound, short trills or harsh pulses, produced when
rival males come into close proximity.
● Function: Used to deter other males from encroaching on a calling site or to
assert dominance over a particular perch or territory.
