Jumping spiders (family Salticidae) are funny companions. My “office” is outside our house on a shadowy veranda. Most of the time when I work on my laptop computer, one of these funny and curious guys jumps either on my fingers or on the screen.
Jumping spiders have an excellent vision. When the little spider (about 8 to 12 mm) stays on the screen, I can “hunt” them with the cursor arrow. Maybe I should write, the spider hunts the arrow. This little spiders have many different colors. Someones look like a zebra, others have green or yellow stripes or dots.
Being always inspired by these little acrobats, I did a bit research. I found another astonishing fact:
Jumping spiders (family Salticidae) are masters of miniature vision, achieving higher spatial resolution in relation to body size than any other animal. While most members of this family do not use color in intraspecific communication, several genera serve as emerging examples of rapid evolutionary radiation in sexual display coloration. These include the Australasian Maratus ‘peacock’ spiders, and the American genus Habronattus. Males of these genera are often brilliantly colored on body surfaces they showcase to females during elaborate courtship dances. However, molecular and electrophysiological data suggest that color vision in the acute ‘principal’ eyes of most jumping spiders is based on only two types of photosensitive pigment, one sensitive to ultraviolet (UV) light, the other to green light. Habronattus jumping spiders may achieve substantially better color vision via a mechanism previously unknown in spiders: the shifting of sensitivity of a subset of their photoreceptors from green to red via a long-pass filter positioned in their retina. Trichromatic vision resulting from this filter system should markedly enrich these animals’ perception of color, including reds, oranges and yellows often found in their courtship displays. (Excerpt of an article by Daniel B. Zurek, Thomas W. Cronin, Lisa A. Taylor, Kevin Byrne, Mara L.G. Sullivan, and Nathan I. Morehouse)
These spiders do absolutely not harm you. You may play with them letting them jump from one hand to the other or turn around your fingers. These little animals may even help people with arachnophobia – the fear of spiders. People with arachnophobia tend to feel uneasy in any area they believe could harbor spiders or that has visible signs of their presence, such as webs. If arachnophobics see a spider, they may not enter the general vicinity until they have overcome the panic attack that is often associated with their phobia. Some people scream, cry, have trouble breathing, have excessive sweating or even heart trouble when they come in contact with an area near spiders or their webs. In some extreme cases, even a picture or a realistic drawing of a spider can also trigger fear.
Watch this little spider. It is beautiful …