Studies in animal aggregations: Further studies on oxygen consumption and automy of the brittle star, Ophioderma

✍ Scribed by Allee, W. C. ;Fowler, J. R.

• Publisher: John Wiley and Sons
• Year: 1932
• Tongue: English
• Weight: 961 KB
• Volume: 64
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1400640103

✦ Synopsis

Earlier studies (Allee, '27) upon some of the physiological effects of aggregation of the brittle star, Ophioderma brevispina, have shown that these animals form aggregations in the most shaded region of their laboratory containers, or, if environmental influences are equal, around some quiet individual. These aggregations form as a result of individual responses to environmental conditions rather than because of a social appetite. In nature, these starfishes crawl over eel-grass and are not aggregated during summer and early autumn. In fact, in the laboratory, the more nearly the conditions approach those found in nature, the smaller is the tendency to collect in dense aggregations. The social attribute which most nearly characterizes these groupings is that of toleration for the presence of others in the same general location.

Outside the breeding season, a n initial physiological effect of these aggregations upon the individuals composing them is shown in a lessening of the rate of oxygen consumption, probably due to a decreased muscular tonus following the dose grouping. I n the absence of food and with the proper volume of water, such aggregations soon come to consume oxygen at a higher rate than do similar numbers of individuals isolated ' This work has been supported in part by a. grant from the Rockefeller Foundation t o aid investigations in the biological sciences a t The University of Chicago.