Ever seen an insect struggling for its life in a spider’s web and wondered how clever the spider catches its prey? A study carried out at Oxford has shown that the webs of the spiders move toward the prey due to an Electrically Charged ‘Glue’ spread on the surface of the web.
Fritz Vollrath, professor at University of Oxford, Department of Zoology and his colleagues say that the electrostatic charge on the web causes it to attract all kind of charged particles including pollens, insects, dust or any other material. Not only that, but it has also been shown by Oxford’s researchers that the webs covered with charged glue distort Earth’s electric field to a few millimeters of web, that is how insects detect and avoid a spider’s web, using their antennae or electric sensors that detect any electric distortions.
The web of the spider is shown to be attracted to any particle, irrespective of its charge, that is – if its Positive (+ve) or Negative(-ve). That’s how even the smallest particles are caught in the web. The research claims, due to their affinity for any charged airborne particle, the webs can be used to filter airborne pollutants as an alternative to expensive industrial Sensors.
According to Vollrath, the webs can be used to filter aerosols and air pollutants. As the electric attraction pulls the particles to the web, these webs can be easily harvested to monitor pollution levels. Whats more interesting is that the type of airborne chemicals present in the web can even be detected by the web’s shape, that is because when given certain drugs, spiders produce different types of webs like when given LSD they produce webs with beautiful patterns while when given caffeine the patterns of webs produced are not so nice.
Spiders eat their webs to recycle them. Webs are eaten along with the particles that were attracted by the electrically charged web, so the nature of particles determines the shape of web. One can easily tell by looking at the web that which particle has been attracted and is present in the web.
The presence of charge can also explain how insects avoid being captured by the web. The distortion caused by the web in the earth’s electric field can be sensed by the insects using their antennae. The organs that sense distortion are called e-sensors and are present at the tip of antennae, the charge on tip is different from the charge on the rest of body. When insect approaches the charged web the tip of the antennae slightly moves which is felt by the insects.
Though it can be an effective way to avoid webs, it is not yet clear if insects even use that method because the distortion caused by the webs is short-lived and the insect might not be able to detect it, thus unable to defend itself from being captured by the deadly web and get eaten.
[Image Credit: FrenchHouseHunt]