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Experimental heterochrony in hydractiniid hydroids: Why mechanisms matter
Author(s) -
Blackstone Neil W.,
Buss Leo W.
Publication year - 1993
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1046/j.1420-9101.1993.6030307.x
Subject(s) - heterochrony , biology , life history , evolutionary biology , zoology , ecology , annelid , life history theory , ontogeny , genetics
Abstract As with most clonal organisms, hydractiniid hydroids display a range of morphological variation from sheet‐like to runner‐like forms. Life history differences correlate with these morphological traits, exhibiting patterns commonly found in studies of heterochrony. Experimental studies of two hydractiniid species show that both morphological and life history heterochronies correlate with patterns of gastrovascular circulation. Similar experimental perturbations of energy metabolism, however, have opposite heterochronic effects on the two species. Treatment with 2,4‐dinitrophenol, an uncoupler of oxidative phosphorylation, produced diminished peripheral circulation and sheet‐like peramorphic morphologies in the runner‐like species, Podocoryne carnea . In contrast, similar manipulations of the sheet‐like species, Hydractinia symbiolongicarpus , produced variable peripheral circulation and more runner‐like, juvenilized morphologies. These results diverge at the level of morphological and life history pattern, but are consistent when viewed in terms of the physiology of the gastrovascular system. Interpretations of patterns of heterochrony must focus on the physiological and developmental mechanisms which mediate the expression of heterochronic traits.