Ontogenetic changes in visual sensitivity of the parasitic salmon louse Lepeophtheirus salmonis

Overview
TitleOntogenetic changes in visual sensitivity of the parasitic salmon louse Lepeophtheirus salmonis
AuthorsNovales Flamarique I, Browman HI, Bélanger M, Boxaspen K
TypeJournal Article
Journal NameThe Journal of experimental biology
Volume203
IssuePt 11
Year2000
Page(s)1649-57
CitationNovales Flamarique I, Browman HI, Bélanger M, Boxaspen K. Ontogenetic changes in visual sensitivity of the parasitic salmon louse Lepeophtheirus salmonis. The Journal of experimental biology. 2000 Jun; 203(Pt 11):1649-57.

Abstract

The salmon louse, Lepeophtheirus salmonis, is an ectoparasitic copepod of salmonid fishes whose life cycle involves two broadly defined, free-living larval stages, the nauplius and the copepodid. After settling on a host, the copepodid goes through various transformations to become a mobile adult. We recorded swimming responses of free-swimming salmon lice at the naupliar, copepodid and adult stages to the onset (ON) and offset (OFF) of lights of varying spectral irradiance and polarization. Nauplii showed a prominent swim-up OFF response across the spectrum 352-652 nm, but no ON response. Copepodids exhibited a swim-up ON response and a passive (sinking) OFF response across the same spectral range. Adults showed active swim-up responses to both ON and OFF stimuli, although the OFF response was proportionately stronger. The spectral range of the adult ON and OFF responses was the same as that of the copepodids and slightly greater than that of the nauplii, which did not exhibit responses at 652 nm. The absolute sensitivity of copepodids under white light (approx. 10(-13) photons m(2) s(1)) was higher than that of nauplii (approx. 10(-17) photons(-1) m(2 )s, OFF response) and that of adult female lice (approx. 10(-14) photons(-1)m(2)s). This suggests that the naupliar visual system is best suited for detection of shadows (e.g. the host) under a bright light field (daylight hours), while copepodids and adults may be more specialized for host detection at crepuscular periods and during the night, when light levels are low. None of the developmental stages responded to the rotation of the plane of polarized light or exhibited any difference in directed response when polarized light was used in place of diffuse light.

Author Details
Additional information about authors:
Details
1I Novales Flamarique
2H I Browman
3M Bélanger
4K Boxaspen
Properties
Additional details for this publication include:
Property NameValue
Publication ModelPrint
ISSN0022-0949
pISSN0022-0949
Publication Date2000 Jun
Journal AbbreviationJ. Exp. Biol.
LanguageEnglish
Language Abbreng
Publication TypeJournal Article
Journal CountryENGLAND
Publication TypeResearch Support, Non-U.S. Gov't
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PMID: PMID:10804155