Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2002-6-27
pubmed:abstractText
The eye of Ligia exotica is of the apposition type and has open rhabdoms. The facets are hexagonal, and the dioptric apparatus consists of a flat cornea and a spherical crystalline cone placed in the center of two large cone cells. Each ommatidium has seven regular retinula cells and one eccentric cell; a basement membrane forms the proximal boundary of the retina. With increases in body size from 0.6 to almost 4.0 cm, facet numbers and ommatidial diameters increased from 800 to 1500 and 35 microm to 100 microm, respectively; eye length and width grew from 1.2 to 3.2 and 0.9 to 2.5 mm, respectively; and length of dioptric apparatus and width of retinal layer changed from 70 microm to 180 microm and about 70 microm to 120 microm. Visual angles and interommatidial angles of centrally located ommatidia remained constant at about 30 and 6.9 degrees, respectively. An almost perfect linear relationship was found when eye length was plotted against the product between the square root of the total number of ommatidia and the ommatidial diameter. No difference between males and females was observed in any of the relationships, but the results suggest that, compared with smaller specimens, larger ones possess increased absolute sensitivity in single ommatidia, increased sensitivity to point sources, and overall larger angular visual fields for the eye in its totality. This means that larger individuals of L. exotica (which are also faster) have an advantage over smaller individuals at night, but that smaller individuals may cope better with bright lights. Vision in L. exotica seems useful not only in detecting potential danger, but also in locating and approaching cliffs from a distance of 2-4 m when swimming in seawater.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-3185
pubmed:author
pubmed:issnType
Print
pubmed:volume
202
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
223-31
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Postembryonic eye growth in the seashore isopod Ligia exotica (Crustacea, Isopoda).
pubmed:affiliation
Department of Biology, University of Oulu, P.O. Box 3000, Finland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't