|Description:||Under a magnification of 40X, this scanning electron microscopic (SEM) image revealed some of the ultrastructural architecture found in a brown recluse spider’s, Loxesceles reclusa, web that had entrapped an unidentified ant. Though the prey had been enwrapped in a silk cocoon, there were still some of its body parts that were visible such as one of its two compound eyes, and one of its two segmented antennae (background). |
The antenna is composed of three main regions: scape, pedicle, and flagellum. The scape attaches the sensory organ to the head region, and the pedicle joins the distal, jointed flagellum to the scape.
The compound eye is given this name due to the fact that the single large eye is really made up of many repeating units known as "ommatidia”. Each ommatidium is composed of separate units made up of a photoreceptor cell, support cell, and pigment cells. Though each of these visual mechanisms functions as a separate organ, together they provide the organism with a "compound” picture of its environment. Due to what is referred to as the "flicker effect”, the compound eye is made very sensitive to movement, with each ommatidium turning on and off, as objects pass across its field of view. The bilateral anatomical placement of the insect's eyes provides the organism with a very wide range of visual sensitivity.