Tree frogs help Internet connections


This video is called Japanese tree frog calls.

From ScienceDaily:

Frog Calls Inspire a New Algorithm for Wireless Networks

(July 17, 2012) — Males of the Japanese tree frog have learnt not to use their calls at the same time so that the females can distinguish between them. Scientists at the Polytechnic University of Catalonia have used this form of calling behaviour to create an algorithm that assigns colours to network nodes — an operation that can be applied to developing efficient wireless networks.

How can network nodes be coloured with the least possible number of colours without two consecutive nodes being the same colour? A team of researchers at the Polytechnic University of Catalonia have found a solution to this mathematical problem with the help of some rather special colleagues: Japanese tree frogs (Hyla japonica).

These male amphibians use their calls to attract the female, who can recognise where it comes from and then locate the suitor. The problem arises when two males are too close to one another and they use their call at the same time. The females become confused and are unable to determine the location of the call. Therefore, the males have had to learn how to ‘desynchronise’ their calls or, in other words, not call at the same time in order for a distinction to be made.

“Since there is no system of central control organising this “desynchronisation,” the mechanism may be considered as an example of natural self-organisation,” explains Christian Blum. With the help of his colleague Hugo Hernández, such behaviour provided inspiration for “solving the so-called ‘graph colouring problem’ in an even and distributed way.”

A graph is a set of connected nodes. As in the case of the frog’s ‘desynchronised calls’, operating in a ‘distributed’ fashion implies that there is no other way of central control that helps to solve the problem with a global vision and all the information on the situation.

In the same way, the researchers have devised a new algorithm for assigning colours to network nodes ensuring that each pair of connected nodes is not the same colour. The end goal is to generate a valid solution that uses the least amount of colours.

Application to WiFi connections

As Blum outlines, “this type of graph colouring is the formalisation of a problem that arises in many areas of the real world, such as the optimisation of modern wireless networks with no predetermined structure using techniques for reducing losses in information packages and energy efficiency improvement.”

This study falls under the field of ‘swarm intelligence’, a branch of artificial intelligence that aims to design intelligent systems with multiple agents. This is inspired by the collective behaviour of animal societies such as ant colonies, flocks of birds, shoals of fish and frogs, as in this case.

1 thought on “Tree frogs help Internet connections

  1. Vision stimulates courtship calls in the grey tree frog

    Study reveals the role of vision in frog mating rituals

    Male tree frogs like to ‘see what they’re getting’ when they select females for mating, according to a new study by Dr. Michael Reichert from the University of Wisconsin-Milwaukee in the US. His work, which is one of the first to test the importance of vision on male mating behaviors in a nocturnal anuran (frog or toad), is published online in Springer’s journal Behavioral Ecology and Sociobiology.

    Animals display a number of courtship behaviors and are able to modulate these behaviors depending on the likelihood of mating. For example, displaying males may increase the expression of a costly courtship behavior when receptive females are nearby. Male anurans also exhibit unique behaviors when females are in close proximity, including courtship calls.

    Reichert’s work looks at the role of vision on the production of courtship calls in the grey tree frog, Hyla versicolor. Frogs are highly sensitive to motion so visual cues are likely to stimulate the production of courtship calls.

    Male and female frogs were captured from local ponds in Boone County, Missouri. The males were then split into two groups – one group could see the female at close range; the other group were separated from the female by an opaque screen. Reichert recorded and compared the vocal behavior – both number of courtship calls and their duration – of both groups of male frogs.

    He found that males were highly responsive to the visual cues from the female, and they altered their calling behavior to be more attractive to the female. Specifically, males were significantly more likely to give courtship calls when they were able to see an approaching female, and their calls were longer.

    Reichert concludes: “In the noisy chorus environment, males can only attract females from a limited distance; thus, a strategy of monitoring the environment for female cues, and only producing the highest performance calls when females are present, should balance the costs of high performance calls while maximizing the likelihood of attracting a mate.”

    ###

    Reference
    Reichert MS (2012). Visual cues elicit courtship signals in a nocturnal anuran. Behavioral Ecology and Sociobiology; DOI 10.1007/s00265-012-1446-9

    http://www.eurekalert.org/pub_releases/2012-11/s-vsc111912.php

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