Biol. Bull. Sign up for etocs!
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Biol Bull 151: 126-140. (August 1976)
© 1976 Marine Biological Laboratory
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by FORWARD, R. B.
Right arrow Search for Related Content
PubMed
Right arrow Articles by FORWARD, R. B., JR.

A SHADOW RESPONSE IN A LARVAL CRUSTACEAN

RICHARD B. FORWARD JR. 1

1 Duke University Marine Laboratory, Beaufort, N. C. 28516, and Zoology Department, Duke University, Durham, N. C. 27706

1. A shadow response consisting of oriented movement to light and gravity was studied by means of a closed circuit television system for stage I zoeae from the crab Rhithropanopeus harrisii.

2. If larvae are irradiated at an intensity that induces positive phototaxis and the light is extingushed, both light-and dark-adapted larvae show a descent. Since this response involves passive sinking, it is termed a sinking response. The minimum time that the light must be extinguished to evoke the response is 20 to 30 milliseconds.

3. If the light intensity is reduced to a level that should induce negative phototaxis, light-adapted larvae show a sinking response followed by a negative phototaxis. The time delay between the responses is related to the initial stimulus intensity and duration.

4. The minimum decrease in intensity that induces the sinking response is equivalent to a reduction by a 0.5 O.D. neutral density filter while the maximum response occurs at optical densities of 1.0 to 1.1 and greater. These values are independent of stimulus time, intensity, and direction.

5. It is argued that these behaviors are appropriate for avoiding zooplankton predators like ctenophores which do not visually sight and actively pursue their prey. The ctenophore Mnemiopsis leidyi is abundant in the Beaufort, North Carolina, area and spectrophotometric determinations of this species' apparent O.D. indicate that animals larger than a certain size attenuate the light sufficiently to evoke the shadow response.




This article has been cited by other articles:


Home page
 J PLANKTON RESHome page
J. H. Cohen and R. B. Forward Jr
Ctenophore kairomones and modified aminosugar disaccharides alter the shadow response in a larval crab
J. Plankton Res., February 1, 2003; 25(2): 203 - 213.
[Abstract] [Full Text] [PDF]

Home page
 Biol. Bull.Home page
S. Johnsen
Hidden in Plain Sight: The Ecology and Physiology of Organismal Transparency
Biol. Bull., December 1, 2001; 201(3): 301 - 318.
[Abstract] [Full Text] [PDF]

Home page
 Integr. Comp. Biol.Home page
T. W. Cronin and R. N. Jinks
Ontogeny of Vision in Marine Crustaceans
Integr. Comp. Biol., October 1, 2001; 41(5): 1098 - 1107.
[Abstract] [Full Text] [PDF]

Home page
 J. Exp. Biol.Home page
D Jamieson and A Roberts
Responses of young Xenopus laevis tadpoles to light dimming: possible roles for the pineal eye
J. Exp. Biol., January 6, 2000; 203(12): 1857 - 1867.
[Abstract] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1976 by the Marine Biological Laboratory.