Instructions
Select the spider inventory you are interested in the main menu and chose a family to show the species included. To enter any species pages just click on its name. Click in the thumbnails to download the high resolution images that will pop-up on separate resizable windows. This was done with the purpose of comparing images side by side after organizing them on the screen.
Please send your comments and species identifications to: fap@ciencias.unam.mx
Measuring spider diversity
Collecting all spider species in a relatively large area is impossible, therefore estimations of species richness and other statistical tools are needed to measure community parameters. Therefore applying standardized collecting protocols is crucial to achieve this and to compare communities between places.
Over many years almost all Arachnologists have used the same collecting protocol with some minor variations. At its core it makes explicit the collecting effort for direct methods and usually samples one hectare of area. Please follow these two simple rules and your spider inventory will be easily compared with similar studies and more cited.
- Make explicit the collecting effort units, for Araneomorphae 1 hour/person/method is the standard.
- Use areas equal or greater than 2,500 m² (plots of 50 X 50 meters). This will allow species/area extrapolations with other studies. Transects are NOT recommended because they cover considerably less area and meaningful extrapolations are impossible to do.
Tracing a plot with simple tools
A sampling plot of any area can be traced with a compass, a long measuring tape and two people. Set a given orientation in the compass lets say North to South. Trace an imaginary line in the compass from 0° to 180° and project it to a land mark where the other person must place the measuring tape in a straight line. For the corners add 90° keeping track the turn orientation to close the square. For this example the other three directions would be 90° to 270°, 180° to 0°, and 270° to 90°. For irregular polygons the job is done with a ruler, a notebook and some knowledge of basic geometry. If done correctly you must return near or exactly where you started the plot.