Artificial shelters for spiders
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Artificial shelters, also known as artificial cover objects, are a type of trap that is used to capture spiders. Artificial shelters are designed to be a place where a spider can build its web. These traps can be used in research to record the presence or absence of a spider, the approximate age and the species of the spider. This type of trap is also considered suitable for the insect hobbyist.
Artificial shelters made to capture arachnids can be made out of nearly any construction material at hand. Some of the more common materials are wood and plastic. However, other materials like cardboard or bubble wrap have been used. Arachnid traps can vary greatly in their design as well. However, the basic principle remains: these traps are meant for the animal to seek shelter inside.
To properly attract spiders, one must make the area of the trap dark, to make it a desirable place for the target to build a web. This can be done either by covering the surface that lets in light with black plastic and/or positioning the trap in a way that light doesn't hit it.
Artificial shelters can be made out of many different materials, though some of the more common ones are listed below.
- Untreated pine wood
- Transparent acetate or acrylic for a “viewing window” stapled over the wood shelter.
- Black polythene to block light from entering the shelter when positioned.
- Plastic coated wire for tree attachment (optional)
- Corrugated cardboard
- Bubble wrap
- Twine or tape, used to secure trap to tree (optional)
Most of the advantages and disadvantages depend on the materials used in constructing the trap. For example, using cardboard may be inexpensive, easy to assemble, and economically advantageous to create many at once, but will deteriorate quickly with any precipitation. Conversely, an artificial cover object made of untreated pine wood may be more expensive and require specialty skills and equipment to build, but is sturdy and long lasting. When choosing materials to build an artificial shelter keep in mind the overall cost, durability, ease of assembly, and transportation of the traps, as well as your personal needs.
The placement of these traps is completely dependent on which type of spiders are desired. Also, the time of the year these traps are set will greatly influence the species and maturity of caught spiders. For grass spiders (aka funnel weavers), mature adults can best be caught in the late summer and early fall. Placement of traps for this species would be most effective in a grass-like habitat on the ground. For best results, these traps should be set and left undisturbed for a length of time. This time span can range from a couple weeks to a month or more. The time given for collection varies, but there is generally a higher rate of capture the longer the trap is set.
Collection of spiders from artificial cover traps is possible but methods vary with the design of the trap. Collection involves removing the spider(s) from the trap and placing them into containers for long term preservation. Glass jars are most often used for this since they are transparent and do not deteriorate in reaction to the chemicals used for preserving specimens. For long and narrow traps, tipping the opening into the collection jar and tapping it until the spider falls out is effective. However, it is sometimes necessary to use a long, thin object to dislodge the spider. For traps such as the artificial cover object, placing the collection jar just beneath the spider and using a probe to push it into the jar seems to be an effective method. After the spider has been caught, one usually prepares it for long term preservation. Ethanol mixed with water has been considered the best by many for killing and preserving arachnids. However, pure ethanol is relatively rare and expensive, so isopropyl alcohol is often used instead. This preservative does not harden the spiders as much as ethanol. When using isopropyl alcohol, a 70-80% concentration solution is most effective and can be purchased at any convenience store.
- Hodge, S., C. J. Vink, J. C. Banks, and M. H. Bowie. 2007. The use of tree-mounted artificial shelters to investigate arboreal spider communities in New Zealand nature reserves. Journal of Arachnology 35:129-136.
- Isais, M., B. Badino, and G. Badino. 2006. Comparison of polyethylene bubble wrap and corrugated cardboard traps for sampling tree-inhabiting spiders. Environmental Entomology 35:1654–1660.
- Rondon, Silvia, and M. Corp. 2011. Preserving insects and related arthropods. Oregon State University Extension Service. June 28, 2011.