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How do insects communicate?

How do ants know what path to follow? Which mechanisms do some male and female moths use to meet each other when located far away? As humans along history, insects have developed different ways to communicate with each other.

Do you want to know how and for what purpose do insects communicate by all its senses? Keep reading!

Insects language

Communication is defined as an exchange of information between two (or more) individuals: the one/s that transmits the message (emitter) and the one/s that receives and processes that message. While in humans communication passes through a long learning process, in insects the same process tends to be an inborn mechanism: each newborn individual has an specific vocabulary shared only with organisms of its own species.

On the other hand, we tend to see communication as an obvious process (if the emitter says “Thank you!” we expect the receptor to say “You’re welcome” in return). In insects, likewise in other animals, communication can take place in a way that information can’t be appreciated for us (humans).

Thus, it’s be better to say that communication is an act or condition of any part of an organism that alters the behavior of another organism. What does it means? That the emitter insect sends a missage to the rest of organisms by doing some action (e.g. an acoustic signal) or maybe by developing some physical trait which informs the rest of individual of some stuff (e.g. the color pattern of wings of some butterflies), in order to induce some answer or changes on the receptors that would benefit one or both of them.

Why do insects communicate?

Insects communicate both with organisms of the same species (intraspecific communication) and directly or indirectly with organisms of other species (interspecific communication) for many reasons:

  • Reproduction: to look for a mate, courtship…
  • To identify members of the same species or even to warn other organisms of its own presence.
  • To localize sources of recourses : food, nidification places,…
  • As an alert signal towards potential hazards.
  • To defend territory.
  • As a way to camouflage or to mimic other organisms (Do you want to learn more about animal mimicry? click here!).

Language through senses

Insects use almost all senses to communicate. Along this section, we’ll analyze one by one all communication systems that insects developed through the “five sense”, just like some of the flashiest examples.

Tactile communication: “The touch”

Tactile communication in insects would be equivalent to the sense of touch in vertebrates. Although nervous system in insects is underdeveloped compared to the one of vertebrates, tactile communication is based on the same principle: it must be some type of direct or indirect physical contact between the emitter of the message and the receptor.

  • “Tandem running”: Follow the leader!

Since long ago, we know that ants walk in line one after another because some of them leave a chemical track that the rest of individuals follow to not get lost. But, aside of emitting these chemical signals, some ant species seem to establish an strategic physical contact system known as tandem running: the ant located behind touches the abdomen of the one that is immediately before it (the leader) with its antennae; moreover, if the leader stops feeling the antennae of the one behind, the leader will turn and wait for the one that follows it.

tandem running
“Tandem running” steps observed in ants (it has also been studied in some termites species). Image source: link.

This video from Stephen Pratt Youtube channel shows two ants performing this kind of contact known as “tandem running”:

  • Dancing bees

Honey bees (Apis mellifera) perform dances to show other members of their colonies where nectar is located (direction and distance) and also if it has a high quality. Bees dance inside their hives, so this performance takes place in deep darkness. So, you’ll ask yourself: why dance if no one sees you? Because the sense of sight is not necessary in this case to transmit the information: the rest of bees don’t perceive the movements in essence, but only the vibrations the dancing bee transmits trough all the hive will moving.

Look at these dancing bees! (video from Ilse Knatz Ortabasi Youtube channel):

Chemical communication: “smell and taste” 

Chemical communication is probably the most extended communication mechanism among insects. In this type of communication, the emitter scatters chemical substances at the environment which are detected by other organisms. There exists a lot of types of chemical substances: pheromones (for finding a mate), allelochemicals (as alarm signals, as a defensive system…), etc.

Even more important than how they scatter those substances, is the system they use to detect them: insects have more or less specialized receptors located on their antennae, their legs, etc. We can say they can savor and smell these substances with almost all parts of their body!

  • Love gives you wings…and pheromones!

Females of some moth species emit pheromones that can be detected even by male moth located kilometers away. This is the case of Small Emperor Moth females (Saturnia pavonia), which attract males located almost 16km away.

Emperor-moth-pair-with-male-above-and-female-below
Saturnia pavonia male (above) and female (below). Picture by Stephen Dalton ©.
  • Your smell betrays you!

Communication can take place among insects of the same or different species. Euclytia flava is a bedbug parasitoid (learn more about parasitoids here) that detects its hosts by the way they smell: more accurately, by detecting the chemical substances that the hosts emit (these type of substances that benefit the receptor but not the emitter are known as kairomones).

Euclytia flava (Copyright © 2013 Christopher Adam).

Auditory communication: “the hearing” 

Insects emit a wide variety of sounds in different frequencies, amplitude and periodicity, and each species has a very well defined pattern. In fact, only by registering and analyzing insect’s sounds we can identify the species that has emitted them.

While humans can detect sounds in a range from 20 to 20.000Hz, insects can emit and detect sounds above this range (some crickets can produce ultrasounds above 80.000Hz).

  • The summer sound

Cicades are amazing for many reasons: they remain more than 17 years in a nymph state underground until they reach adulthood and also emit a wide range of singings from sunrise to sunset during summer months. They emit these sound by stridulatory organs located in the abdomen, and are received by an auditory organs located on their legs or thorax.

Listen to this cicade singing! (Dangerous insects planet Youtube channel). Can see how its abdomen vibrates?

Some cicades are able to emit sounds that exceeds 120 decibels (they almost reach the human ear pain threshold!). However, some small cicade species emit sounds in a so elevated frequency that can’t be listened by humans, but that could be painful for other animals.

The sounds of cicades have many purposes, although they use it specially for finding a mate or to delimitate their territory.

  • “I’m all antennae”

Some studies reinforce the idea that males of some mosquitoes species have a higher sensibility in their antennae to detect the vibrations emitted by the beating of female wings through the air.

deaa508d2de52c63b974487ba1896374
Electron microscopy image of a male mosquito in which we can appreciate its feathery antennae; these pilosities heighten its sensibility (This image has been taken with EVO® MA10; picture by ZEISS Microscopy, CC).

Visual communication: “The sight”

Visual communication in insects takes place by two main systems: body color patterns and light signals (bioluminescence).

Each species has specific color patterns, which can be useful for identifying members of the same species, also to attract a mate o even to alert other organisms about its dangerousness (aposematic mimicry; learn more about it here), or to drive away predators. On the other hand, there are also species that emit light signals to attract other specimens (e.g. fireflies or beetle from Lampyridae family).

  • Eyes…or only spots?
Caligo memnon
Caligo memnon, with its spots that resemble two big owl eyes and witch allow them to drive away predators (Picture by Edwin Dalorzo, CC).
  • Lights in the dark

Fireflies are the most common example of communication mediated by bioluminescent signals, but there exist more insects which are able to emit light:

pyrophorus-noctilucus-glowing-click-beetle
The click beetle (Pyrophorus Noctilucus) has two small bioluminescent organs located behind its head. The light of these organs get more intense when being menaced (Image source: firefly.org).
oruga luz
Larvae or larviform adult females from the beetle genus Phrixothrix emit two types of light: green and red. They emit red light by two organs located in their heads only when they feel menaced in order to alert other larvae about the presence of predators (image source: firefly.org).

.            .            .

As you see, insects communicate in some different ways. Do you dare to discover how do insects that live near you communicate?

References

  • Gopfert M.C; Briegel H; Robert D. (1999). Mosquito Hearing: Sound-Induced Antennal Vibrations in Male and Female Aedes Aegypti. The Journal of Experimental Biology. 202: 2727-2738.
  • J.R. Aldrich, A. Zhang (2002). Kairomone strains of Euclytia flava (Townsend), a parasitoid of stink bugs. Journal of Chemical Ecology, Volume 28, Issue 8, pp 1565-1582.
  • Nigel R. Franks, Tom Richardson (2006). Teaching in tandem-running ants. Nature 439, 153.
  • Insectos: la mejor guía de bichos. Parragon Books Ltd.
  • Hometrainingtools.com: insect communications
  • www.cals.ncsu.edu/course/ent425/tutorial/Communication/
  • Firefly.org

Main image by Radim Shreider © (National Geographic Photo Contest 2012).

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