1. Morphological change and phenotypic plasticity in response to water velocity in three species of Centrarchidae
- Author
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Istead, A.E., Yavno, S., and Fox, M.G.
- Subjects
Morphology (Animals) -- Research ,Zoological research ,Phenotypic plasticity -- Research ,Sunfishes -- Environmental aspects -- Genetic aspects -- Physiological aspects -- Natural history ,Zoology and wildlife conservation - Abstract
Morphological responses to flowing water have been documented in many fishes, but rarely reported in species with gibbose body types, despite their use of riffles in rivers and streams. In this study, we compared morphological responses to water flow in three gibbose centrarchids: bluegill (Lepomis macrochirus Rafinesque, 1819), pumpkinseed (Lepomis gibbosus (L., 1758)), and rock bass (Ambloplites rupestris (Rafinesque, 1817)). Flow-through plexiglass units, set to either a sustained flow or static conditions, were used to rear juveniles from each species for an 80-day period. All three species developed more streamlined body forms, longer and thinner caudal peduncles, and longer pectoral fins when reared in sustained current. Pumpkinseed exhibited the highest level of phenotypic plasticity in response to water flow, followed closely by bluegill; rock bass was the least plastic species. Rock bass developed longer predorsal and prepectoral lengths, which differ from the morphological changes observed in bluegill and pumpkinseed. The findings not only suggest that some gibbose fishes are capable of exhibiting strong phenotypic responses to water flow, but that many morphological changes are species specific, even within the same taxonomic family. Lastly, all three species developed shorter dorsal fin base lengths when reared under flowing condition, which differs from some previously documented work on fusiform fishes. The results of this study provide a better understanding of how morphology in three closely related species varies in response to environmental conditions. Key words: bluegill, Lepomis macrochirus, common environment, gene-environment interaction, locomotion, pumpkinseed, Lepomis gibbosus, rock bass, Ambloplites rupestris, reaction norms. Des reactions morphologiques a l'ecoulement de l'eau ont ete documentees chez de nombreux poissons, mais rarement signalees pour des especes presentant des types de corps gibbeux, malgre l'utilisation par ces especes des seuils dans les rivieres et ruisseaux. Nous avons compare les reactions morphologiques a l'ecoulement de l'eau chez trois centrarchides gibbeux, dont le crapet arlequin (Lepomis macrochirus Rafinesque, 1819), le crapet-soleil (Lepomis gibbosus (L., 1758)) et le crapet de roche (Ambloplites rupestris (Rafinesque, 1817)). Des unites d'ecoulement en plexiglas dans lesquelles des conditions statiques ou d'ecoulement continu etaient maintenues ont ete utilisees pour elever des juveniles de chacune des especes pendant une periode de 80 jours. Les individus des trois especes presentaient des formes du corps plus allongees, des pedoncules caudaux plus longs et minces et des nageoires pectorales plus fines lorsqu'ils etaient eleves dans un courant continu. Les crapets-soleil presentaient le degre le plus eleve de plasticite phenotypique en reaction a l'ecoulement de l'eau, suivis de pres par les crapets arlequins; les crapets de roche etaient l'espece la moins plastique. Ces derniers etaient caracterises par des longueurs pre-dorsales et prepectorales plus grandes, des changements morphologiques differents de ceux observes chez les crapets arlequins et les crapetssoleil. En plus d'indiquer que certains poissons gibbeux pourraient faire preuve de fortes reactions phenotypiques en reponse a l'ecoulement de l'eau, ces resultats donnent egalement a penser que de nombreux changements morphologiques sont propres a l'espece, meme au sein d'une famille taxonomique. Enfin, les trois especes presentaient des longueurs de la base de la nageoire dorsale moins grandes quand elles etaient elevees dans des conditions d'ecoulement, ce qui tranche avec les conclusions de certains travaux anterieurs sur des poissons fusiformes. Les resultats de l'etude offrent une meilleure comprehension des variations morphologiques en reponse aux conditions ambiantes chez trois especes etroitement reliees. [Traduit par la Redaction] Mots-cles : crapet arlequin, Lepomis macrochirus, milieu commun, interaction gene-environnement, locomotion, crapetsoleil, Lepomis gibbosus, crapet de roche, Ambloplites rupestris, normes de reaction., Introduction Phenotypic plasticity, the ability for a genotype to express alternate phenotypes in response to an environmental condition (West-Eberhard 1989; Agrawal 2001), facilitates the modification of behavioural, life-history, morphological, and [...]
- Published
- 2015
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