Introduction

Communication is the process of transferring information from one animal to another; there are typically three types of roles involved with communication. These are:

• Signaller – Initiates the communication, the signaller must benefit from making the signal
• Receiver – Receives the signals sent by the signaller, these signals are often of benefit to the receiver as well
• Eavesdropper – Takes advantage of the signals generated by the signaller

There are also different forms of communication two of which are:

• Cooperative signalling – Signalling that benefits both parties involved, e.g. a birding singing to attract a mate
• Non-cooperative signalling – Only one party benefits, e.g. the ‘broken wing display’ by birds (The bird pretends to have a broken wing to make it appear an easy target, thus distracting the predator from its young).

Types of Communication

Examples of communication types:

Type of Communication	Example Species	Function
Pheromones	Moth	Pheromones are short chain hydrocarbons which are easily diffused and are detected by vomeronasal organs. Pheromones and their receptors are species specific and so undetectable by predators. It only takes one molecule of pheromone to elicit a response – unlike smell.
Stridulation	Grasshopper	Stridulation is the rubbing together of body parts to produce a sound. Stridulation is used when auditory signals are of more benefit than pheromones (e.g. in long grass pheromones are diffused and harder to detect). Different species produce different sounds and calls via stridulation.
Bioluminescence	Fireflies	A specialised pigment – luciferin releases energy in the form of light by oxidised by the enzyme luciferinase. The light produced is aposematic, this warns predators that they are distasteful. Different species produce different patterns of light.
Alarm Calls	Birds – Bird song	Similar amongst all species, alarm calls alert other members of the group that a predator is nearby. Alarm calls are generated in a way that makes it difficult to pinpoint the exact source.

Bird Song

Bird song differs between habits, differing mainly by frequency. The birds have adapted to produce a song which is designed to travel as far as possible given the habitat.

In open areas, with wind, a higher frequency and rapid songs are best as they allow the message to travel far without being disrupted by the wind.

In more closed habitats such as woodland, purer tones are used. This helps to prevent degradation of the song by obstructions e.g. trees.

Dance Language of Honeybees

The primary use of the honeybee dance language is to communicate the location of food sources to colony mates. The dance involves 2 components:

1. A straight run whilst waggling the abdomen
2. Return back to starting point and repeat but in reverse

This dance conveys information about distance from a food source as well as its direction. The angle of the waggle tells the colony mates the angle of the flower from the sun. The direction of the straight run shows the direction of the flower and the distance of the straight run is related to the distance to the flower. The bees also buzz during the ‘dance’ which also helps to convey the message.

The honey bees are still able to communicate the whereabouts of a food source, even without the sun. On a cloudy day they use their ability to detect polarised light and relate this to the direction of the food source.

The honey bees are able to roughly estimate the distance to the flower by measuring the rate of optic flow. They can roughly estimate their speed by using objects in the distance at and how quickly they pass by, from this they can estimate distance as they know roughly how long they have been travelling.

Experiments have been conducted to show that the dance is an important tool for honey bees. One such experiment measured this by measuring the reproductive success of the honey bees under two conditions:

1. Diffuse light (non-directional) which lead to the bees giving a disorientated dance
2. Orientated light (natural e.g. sun) which allowed the bees to give dances as normal

The bees with the orientated light source had much better reproductive success. The dance becomes very important during winter when food sources run low.