Ballooning (spider)
Encyclopedia
Ballooning is a term used for the mechanical kiting that many spider
s, especially small species, as well as certain mite
s and some caterpillar
s use to disperse through the air. Many small spiders use gossamer
or especially fine silk
to lift themselves off a surface or use the silk as an anchor in mid air. The very fine silk used for ballooning has been called "gossamer" since 1325 and was not originally known to be produced by spiders; by extension, the same word is used metaphor
ically for any exceedingly fine thread or fabric. Biologists also apply the term "balloon silk" to the threads that mechanically lift and drag systems.
A spider or spiderling after hatching will climb as high as it can. The spider then stands on raised legs with its abdomen pointed upwards. This is known as "tiptoeing". After that, it starts releasing several silk threads from its abdomen into the air, which automatically form a triangular shaped parachute. The spider can then let itself be carried away by updrafts of winds, where even the slightest of breeze will do. Most rides will end a few metres later, or a spider can be taken up into a jet stream
, which depends on its mass, posture, the convection
air current
, drag
of silk and parachute to float and travel high up into the upper atmosphere.
Many sailors have reported spiders being caught in their ship's sails, over 1600 km from land (Heimer 1988). They have even been detected in atmospheric data balloons collecting air samples at slightly less than 5 km (16000 ft) above sea level. Apparently it is the most common way for spiders to invade isolated islands and mountaintops. Spiderlings are known to survive without food travelling in air current
s of jet streams for 25 days or longer.
It is generally thought that most spiders heavier than 1 mg are not likely to use ballooning (Suter 1999). Also, because many individuals die during ballooning, it is more unlikely that adults will do it than spiderlings. Adult females of several social Stegodyphus
species (S. dumicola and S. mimosarum), weighing more than 100 mg and with a body size of up to 14 mm, have however been observed ballooning using rising thermals on hot days without wind. These spiders use tens to hundreds of silk strands, which form a triangular sheet with a length and width of about 1 m (Schneider 2001).
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s, especially small species, as well as certain mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...
s and some caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
s use to disperse through the air. Many small spiders use gossamer
Spider silk
Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...
or especially fine silk
Spider silk
Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...
to lift themselves off a surface or use the silk as an anchor in mid air. The very fine silk used for ballooning has been called "gossamer" since 1325 and was not originally known to be produced by spiders; by extension, the same word is used metaphor
Metaphor
A metaphor is a literary figure of speech that uses an image, story or tangible thing to represent a less tangible thing or some intangible quality or idea; e.g., "Her eyes were glistening jewels." Metaphor may also be used for any rhetorical figures of speech that achieve their effects via...
ically for any exceedingly fine thread or fabric. Biologists also apply the term "balloon silk" to the threads that mechanically lift and drag systems.
A spider or spiderling after hatching will climb as high as it can. The spider then stands on raised legs with its abdomen pointed upwards. This is known as "tiptoeing". After that, it starts releasing several silk threads from its abdomen into the air, which automatically form a triangular shaped parachute. The spider can then let itself be carried away by updrafts of winds, where even the slightest of breeze will do. Most rides will end a few metres later, or a spider can be taken up into a jet stream
Jet stream
Jet streams are fast flowing, narrow air currents found in the atmospheres of some planets, including Earth. The main jet streams are located near the tropopause, the transition between the troposphere and the stratosphere . The major jet streams on Earth are westerly winds...
, which depends on its mass, posture, the convection
Convection
Convection is the movement of molecules within fluids and rheids. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids....
air current
Air current
Air currents may be caused by differences in temperature, pressure, or impurity concentration. Temperature differences can cause air currents because warmer air is less dense than cooler air, causing the warmer air to appear "lighter." Thus, if the warm air is under the cool air, air currents will...
, drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
of silk and parachute to float and travel high up into the upper atmosphere.
Many sailors have reported spiders being caught in their ship's sails, over 1600 km from land (Heimer 1988). They have even been detected in atmospheric data balloons collecting air samples at slightly less than 5 km (16000 ft) above sea level. Apparently it is the most common way for spiders to invade isolated islands and mountaintops. Spiderlings are known to survive without food travelling in air current
Air current
Air currents may be caused by differences in temperature, pressure, or impurity concentration. Temperature differences can cause air currents because warmer air is less dense than cooler air, causing the warmer air to appear "lighter." Thus, if the warm air is under the cool air, air currents will...
s of jet streams for 25 days or longer.
It is generally thought that most spiders heavier than 1 mg are not likely to use ballooning (Suter 1999). Also, because many individuals die during ballooning, it is more unlikely that adults will do it than spiderlings. Adult females of several social Stegodyphus
Stegodyphus
Stegodyphus is a genus of araneomorph spiders in the family Eresidae. The 21 species are distributed from Africa to Europe and Asia, with two species Stegodyphus is a genus of araneomorph spiders in the family Eresidae. The 21 species are distributed from Africa to Europe and Asia, with two species...
species (S. dumicola and S. mimosarum), weighing more than 100 mg and with a body size of up to 14 mm, have however been observed ballooning using rising thermals on hot days without wind. These spiders use tens to hundreds of silk strands, which form a triangular sheet with a length and width of about 1 m (Schneider 2001).
See also
- Kite typesKite typesKites are tethered flying objects which fly by using aerodynamic lift, requiring wind, , for generation of airflow over the lifting surfaces.-Kite types:...
- Kite lineKite lineKites have a wing and a kite line , or sometimes more than one line. Kite systems may have more than one kite and more than one kite line....
- Kite mooringKite mooringKites are given mooring by many methods. Watercraft and aircraft traditionally have the term "mooring" applied to making the watercraft or aircraft fast to some external object...
- Spider silkSpider silkSpider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...
- Organisms at high altitudeOrganisms at high altitudeOrganisms can exist at high altitude in a habitat, while flying or gliding, or through man-made systems. Many animals have adapted to high altitude life and some have evolved to cope well with the problems of an environment with a reduced level of oxygen....