Some Observations on the Variations in the Camouflage Devices used by Cyclosa insulana (Costa)

Summary. It is evident that there is a variation in the types of devices used by Cyclosa insulana Costa as camouflage devices in its web. There are also considerable variations in the stages of development through which these devices pass. Comparison of figures 1 and 4 indicate that the stages passed through by the adult spider after its web has been destroyed, recapitulate those passed through during the original development. It appears therefore that the following four statements are correct. The white webbing devices i.e. , the central platform and the diametrical or radial line are used as camouflage devices by young stages of this species. The devices of the fully developed spider is the device which is composed of insect and other debris only, i.e. , the central pad, the diametrical line of insect and other debris, and the diametrical line of pellets. Intermediate between these two extremes there are other stages in which there is a gradual increase in the amount of insect and other debris, and a gradual organization of this debris into the final device form. This introduction of foreign matter is often accompanied by the introduction of a central maze of spiral ribbons, but in some cases this is absent. When introduced the amount of white ribbon decreases as the amount of debris increases. Concentric loops of white webbing are at times introduced before the final device is formed. The young stages of Cyclosa insulana Costa obtain considerable protection from the confusion effect of the central white platform as when they remain stationary they are very inconspicuous. As the abdomen of the spider darkens the efficiency of this protection would be reduced, but the addition of debris, and its orientation into certain device forms, maintains the efficiency at all stages of the spider's development.