PHYSIOLOGICAL-BASIS OF LATITUDINAL GROWTH DIFFERENCES IN MENIDIA-MENIDIA - VARIATION IN CONSUMPTION OR EFFICIENCY

被引:127
作者
PRESENT, TMC [1 ]
CONOVER, DO [1 ]
机构
[1] SUNY STONY BROOK,MARINE SCI RES CTR,STONY BROOK,NY 11794
关键词
CONSUMPTION RATE; GENETICALLY BASED INTRASPECIFIC VARIATION; GROWTH EFFICIENCY; GROWTH-RATE EVOLUTION; LATITUDINAL VARIATION; MENIDIA-MENIDIA; SOMATIC GROWTH RATE;
D O I
10.2307/2389767
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
Growth rate increases with latitude in the Atlantic silverside, Menidia menidia, and the population differences have a genetic basis. Understanding the evolution of this latitudinal gradient in somatic growth required knowledge of the physiological basis of the growth-rate variation. In theory, the faster growth of northern fish must be achieved by higher consumption rates and/or higher somatic growth efficiencies. If, as is frequently assumed, physiological efficiencies are often maximized by natural selection, the faster growth of higher-latitude silversides should result solely from higher consumption rates. We compared the consumption rates and gross growth efficiencies of fish from laboratory-reared stocks that were originated with fish from Nova Scotia (NS) and South Carolina (SC). Experiments were conducted on young, immature fish at a variety of excess ration levels under conditions of controlled fish density at low (17-degrees-C) and high (28-degrees-C) experimental temperatures. NS fish consumed more food (1.7 times) than SC fish and also had significantly higher (1.8-2.2 times) growth efficiencies. Genetic variation in both consumption rate and growth efficiency is therefore responsible for the interpopulation variation in growth rate. This suggests that costs and trade-offs associated with both high consumption rates and high growth efficiency may be the reason why low-latitude populations have submaximal growth rates. The assumption that growth efficiencies are generally at the maxiumum level that a species is physiologically and genetically capable of achieving should be viewed with caution.
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页码:23 / 31
页数:9
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