Compensatory growth strategies are affected by the strength of environmental time constraints in anuran larvae

Abstract

Organisms normally grow at a sub-maximal rate. After experiencing a period of arrested growth, individuals often show compensatory growth responses by modifying their life-history, behaviour and physiology. However, the strength of compensatory responses may vary across broad geographic scales as populations differ in their exposition to varying time constraints. We examined differences in compensatory growth strategies in common frog (Rana temporaria) populations from southern and northern Sweden. Tadpoles from four populations were reared in the laboratory and exposed to low temperature to evaluate the patterns and mechanisms of compensatory growth responses. We determined tadpoles' growth rate, food intake and growth efficiency during the compensation period. In the absence of arrested growth conditions, tadpoles from all the populations showed similar (size-corrected) growth rates, food intake and growth efficiency. After being exposed to low temperature for 1 week, only larvae from the northern populations increased growth rates by increasing both food intake and growth efficiency. These geographic differences in compensatory growth mechanisms suggest that the strategies for recovering after a period of growth deprivation may depend on the strength of time constraints faced by the populations. Due to the costs of fast growth, only populations exposed to the strong time constraints are prone to develop fast recovering strategies in order to metamorphose before conditions deteriorate. Understanding how organisms balance the cost and benefits of growth strategies may help in forecasting the impact of fluctuating environmental conditions on life-history strategies of populations likely to be exposed to increasing environmental variation in the future.

Transgenerational effects and impact of compensatory responses to changes in breeding phenology on antipredator defenses

“…In the treatments without predators, tadpoles from delayed breeding treatments also maintained lower activity than non‐delayed tadpoles during the second half of the experiment, which indicates that the compensatory responses to changes in breeding phenology (i.e., increase in growth and development rates) were not mediated by increased activity, suggesting that other compensatory responses, such as differential energy allocation, higher food intake or better growth efficiency, may be behind the responses to changes in phenology (e.g., Orizaola et al. ). Furthermore, since food was provided ad libitum during the experiment, and there was no need to move much in order to acquire food, the low activity rate in tadpoles exposed to stronger time constraints may be also viewed as an energy saving strategy.…”

Are sexually selected traits affected by a poor environment early in life?

“…[4, 10–12]). Poor nutrition early in life has been shown to adversely affect adult behaviour [11, 13], locomotor performance [14], functional morphology [15, 16], and key adult life-history traits [17–20]. But even if there are no obvious effects, a poor start in life can still decrease fitness.…”

An evolutionary solution of terrestrial isopods to cope with low atmospheric oxygen levels

“…Catch-up growth is a widely used strategy among vertebrates and invertebrates and it commonly occurs under conditions of nutritional deficit (Dmitriew and Rowe, 2007;Hector and Nakagawa, 2012;Malzahn and Boersma, 2012;Morgan and Metcalfe, 2001), but accelerated growth is also seen in response to environmental cues (De Block and Stoks, 2008;Orizaola et al, 2014). Here, we provide evidence for catch-up growth during early development within the motherly brood pouch of terrestrial isopods, which we believe to be the first report regarding catch-up growth in conjunction with oxygen availability.…”