dc.contributor.author |
Yerramilli, D |
|
dc.contributor.author |
Johnsen, S |
|
dc.coverage.spatial |
England |
|
dc.date.accessioned |
2011-06-21T17:27:36Z |
|
dc.date.issued |
2010-01-15 |
|
dc.identifier |
https://www.ncbi.nlm.nih.gov/pubmed/20038658 |
|
dc.identifier |
213/2/249 |
|
dc.identifier.uri |
https://hdl.handle.net/10161/4192 |
|
dc.description.abstract |
Recent evidence that echinoids of the genus Echinometra have moderate visual acuity
that appears to be mediated by their spines screening off-axis light suggests that
the urchin Strongylocentrotus purpuratus, with its higher spine density, may have
even more acute spatial vision. We analyzed the movements of 39 specimens of S. purpuratus
after they were placed in the center of a featureless tank containing a round, black
target that had an angular diameter of 6.5 deg. or 10 deg. (solid angles of 0.01 sr
and 0.024 sr, respectively). An average orientation vector for each urchin was determined
by testing the animal four times, with the target placed successively at bearings
of 0 deg., 90 deg., 180 deg. and 270 deg. (relative to magnetic east). The urchins
showed no significant unimodal or axial orientation relative to any non-target feature
of the environment or relative to the changing position of the 6.5 deg. target. However,
the urchins were strongly axially oriented relative to the changing position of the
10 deg. target (mean axis from -1 to 179 deg.; 95% confidence interval +/- 12 deg.;
P<0.001, Moore's non-parametric Hotelling's test), with 10 of the 20 urchins tested
against that target choosing an average bearing within 10 deg. of either the target
center or its opposite direction (two would be expected by chance). In addition, the
average length of the 20 target-normalized bearings for the 10 deg. target (each the
vector sum of the bearings for the four trials) were far higher than would be expected
by chance (P<10(-10); Monte Carlo simulation), showing that each urchin, whether it
moved towards or away from the target, did so with high consistency. These results
strongly suggest that S. purpuratus detected the 10 deg. target, responding either
by approaching it or fleeing it. Given that the urchins did not appear to respond
to the 6.5 deg. target, it is likely that the 10 deg. target was close to the minimum
detectable size for this species. Interestingly, measurements of the spine density
of the regions of the test that faced horizontally predicted a similar visual resolution
(8.3+/-0.5 deg. for the interambulacrum and 11+/-0.54 deg. for the ambulacrum). The
function of this relatively low, but functional, acuity - on par with that of the
chambered Nautilus and the horseshoe crab - is unclear but, given the bimodal response,
is likely to be related to both shelter seeking and predator avoidance.
|
|
dc.language |
eng |
|
dc.language.iso |
en_US |
|
dc.publisher |
The Company of Biologists |
|
dc.relation.ispartof |
J Exp Biol |
|
dc.relation.isversionof |
10.1242/jeb.033159 |
|
dc.subject |
Animals |
|
dc.subject |
Behavior, Animal |
|
dc.subject |
Form Perception |
|
dc.subject |
Motor Activity |
|
dc.subject |
Orientation |
|
dc.subject |
Strongylocentrotus purpuratus |
|
dc.subject |
Vision, Ocular |
|
dc.title |
Spatial vision in the purple sea urchin Strongylocentrotus purpuratus (Echinoidea). |
|
dc.title.alternative |
|
|
dc.type |
Journal article |
|
duke.contributor.id |
Johnsen, S|0284644 |
|
dc.description.version |
Version of Record |
|
duke.date.pubdate |
2010-1-15 |
|
duke.description.issue |
2 |
|
duke.description.volume |
213 |
|
dc.relation.journal |
Journal of Experimental Biology |
|
pubs.author-url |
https://www.ncbi.nlm.nih.gov/pubmed/20038658 |
|
pubs.begin-page |
249 |
|
pubs.end-page |
255 |
|
pubs.issue |
2 |
|
pubs.organisational-group |
Biology |
|
pubs.organisational-group |
Duke |
|
pubs.organisational-group |
Duke Institute for Brain Sciences |
|
pubs.organisational-group |
Institutes and Provost's Academic Units |
|
pubs.organisational-group |
Trinity College of Arts & Sciences |
|
pubs.organisational-group |
University Institutes and Centers |
|
pubs.publication-status |
Published |
|
pubs.volume |
213 |
|
dc.identifier.eissn |
1477-9145 |
|