The Growth Rate Hypothesis as a predictive framework for microevolutionary adaptation to selection for high population growth: an experimental test under phosphorus rich and phosphorus poor conditions

Abstract

Type of article: Letters Number of words in Abstract: 145 Number of words in Main text: 4897Number of words in Text box: 0 Number of references: 86 Number of Figures: 3 in main text; 5 in appendix Number of Tables: 1 in main text; 9 in appendixAuthorship: KDL and SAJD developed the idea and designed the experiments. KDL carried out the experiments assisted by LZ and performed the data analysis. SP analyzed the microsatellite data. KDL and SAJD wrote the first drafts of the manuscript, and all authors contributed substantially to revisions. Abstract 1The growth rate hypothesis, a central concept of Ecological Stoichiometry, explains the frequently 2 observed positive association between somatic growth rate and somatic phosphorus content (Psom) in 3 organisms across a broad range of taxa. Here, we explore its potential in predicting intraspecific 4 microevolutionary adaptation. For this, we subjected zooplankton populations to selection for fast 5 population growth (PGR) in either a P-rich (HP) or P-poor (LP) food environment. With common garden 6 transplant experiments we demonstrate evolution in HP populations towards increased PGR 7 concomitant with an increase in Psom. In contrast we show that LP populations evolved higher PGR 8 independently of Psom. We conclude that the GRH hypothesis has considerable value for predicting 9 microevolutionary change, but that its application may be contingent on stoichiometric context. Our 10 results highlight the potential of cryptic evolution in determining the performance response of field 11 populations to elemental limitation of their food resources. 2010).the evolution experiment, non-hybrid populations evolved in either a high (HP) or low phosphorus (LP)

Reduced fertilization constitutes an important prezygotic reproductive barrier between two sibling species of the hybridizing Brachionus calyciflorus species complex

“…Our Papakostas et al, 2016;Paraskevopoulou et al, 2020Paraskevopoulou et al, , 2018Zhang et al, 2019). On the other hand, they support earlier conclusions that these species do hybridize (Lemmen et al, 2020;Papakostas et al, 2016) providing a plausible explanation for frequently observed mitonuclear discordances in field populations (Papakostas et al, 2016;Zhang et al, 2019). The mate competition experiment shows that intraspecific fertilizations are more likely to occur than interspecific fertilizations.…”

Experimental evidence of rapid heritable adaptation in the absence of initial standing genetic variation

“…Alternatively, the benign nature of the HP common garden environment may have masked subtle trade-offs. Intriguingly, a similar pattern in performance has been observed in several other studies that have used common garden experiments to compare the fitness of LP-and HP-adapted populations (Declerck et al, 2015;Frisch et al, 2014;Lemmen et al, 2020).…”

Mitigating Elemental Imbalance

“…Alternatively, the benign nature of the HP common garden environment may have masked subtle trade-offs. Intriguingly, a similar pattern in performance has been observed in several other studies that have used common garden experiments to compare the fitness of LP-and HP-adapted populations (Declerck et al 2015;Frisch et al 2014;Lemmen et al 2020). The lack of difference may also be attributed to the fact that generation times of populations fed with phosphorus rich food are considerably shorter than with phosphorus poor food (Zhou et al 2018), and that non-genetic phenotype modifications tend to degrade across generations after the removal of the environmental trigger (Herman et al 2014;Houri-Ze'evi & Rechavi, 2017).…”