scholarly journals Plasticity and flexibility in the anti-predator responses of treefrog tadpoles

2021 ◽  
Vol 75 (10) ◽  
Author(s):  
Castellano Sergio ◽  
Racca Luca ◽  
Friard Olivier
Keyword(s):  
Life History ◽  
Body Size ◽  
Natural Selection ◽  
Phenotypic Plasticity ◽  
Plastic Response ◽  
Heritable Variation ◽  
Size At Metamorphosis ◽  
Adaptive Phenotypic Plasticity ◽  
Similar Body ◽  
And Behavior

Abstract Tadpoles can respond to perceived predation risk by adjusting their life history, morphology, and behavior in an adaptive way. Adaptive phenotypic plasticity can evolve by natural selection only if there is variation in reaction norms and if this variation is, at least in part, heritable. To provide insights into the evolution of adaptive phenotypic plasticity, we analyzed the environmental and parental components of variation in predator-induced life history (age and size at metamorphosis), morphology (tail depth), and behavior of Italian treefrog tadpoles (Hyla intermedia). Using an incomplete factorial design, we raised tadpoles either with or without caged predators (dragonfly larvae, gen. Aeshna) and, successively, we tested them in experimental arenas either with or without caged predators. Results provided strong evidence for an environmental effect on all three sets of characters. Tadpoles raised with caged predators (dragonfly larvae, gen. Aeshna) metamorphosed earlier (but at a similar body size) and developed deeper tails than their fullsib siblings raised without predators. In the experimental arenas, all tadpoles, independent of their experience, flexibly changed their activity and position, depending on whether the cage was empty or contained the predator. Tadpoles of the two experimental groups, however, showed different responses: those raised with predators were always less active than their predator-naive siblings and differences slightly increased in the presence of predators. Besides this strong environmental component of phenotypic variation, results provided evidence also for parental and parental-by-environment effects, which were strong on life-history, but weak on morphology and behavior. Interestingly, additive parental effects were explained mainly by dams. This supports the hypothesis that phenotypic plasticity might mainly depend on maternal effects and that it might be the expression of condition-dependent mechanisms. Significance statement Animals, by plastically adjusting their phenotypes to the local environments, can often sensibly improve their chances of survival, suggesting the hypothesis that phenotypic plasticity evolved by natural selection. We test this hypothesis in the Italian treefrog tadpoles, by investigating the heritable variation in the plastic response to predators (dragonfly larvae). Using an incomplete factorial common-garden experiment, we showed that tadpoles raised with predators metamorphosed earlier (but at similar body size), developed deeper tails, and were less active than their siblings raised without predators. The plastic response varied among families, but variation showed a stronger maternal than paternal component. This suggests that plasticity might largely depend on epigenetic factors and be the expression of condition-dependent mechanisms.

scholarly journals Adaptive phenotypic plasticity in malaria parasites is not constrained by previous responses to environmental change

2019 ◽  
Vol 2019 (1) ◽  
pp. 190-198
Author(s):  
Philip L G Birget ◽  
Petra Schneider ◽  
Aidan J O’Donnell ◽  
Sarah E Reece
Keyword(s):  
Phenotypic Plasticity ◽  
Environmental Change ◽  
Life History Theory ◽  
Environmental Changes ◽  
Negative Consequences ◽  
Plastic Response ◽  
Malaria Parasites ◽  
Host Environment ◽  
Adaptive Phenotypic Plasticity ◽  
Plastic Responses

Abstract Background and objectives Phenotypic plasticity enables organisms to maximize fitness by matching trait values to different environments. Such adaptive phenotypic plasticity is exhibited by parasites, which experience frequent environmental changes during their life cycle, between individual hosts and also in within-host conditions experienced during infections. Life history theory predicts that the evolution of adaptive phenotypic plasticity is limited by costs and constraints, but tests of these concepts are scarce. Methodology Here, we induce phenotypic plasticity in malaria parasites to test whether mounting a plastic response to an environmental perturbation constrains subsequent plastic responses to further environmental change. Specifically, we perturb red blood cell resource availability to induce Plasmodium chabaudi to alter the trait values of several phenotypes underpinning within-host replication and between-host transmission. We then transfer parasites to unperturbed hosts to examine whether constraints govern the parasites’ ability to alter these phenotypes in response to their new in-host environment. Results Parasites alter trait values in response to the within-host environment they are exposed to. We do not detect negative consequences, for within-host replication or between-host transmission, of previously mounting a plastic response to a perturbed within-host environment. Conclusions and implications We suggest that malaria parasites are highly plastic and adapted to adjusting their phenotypes in response to the frequent changes in the within-host conditions they experience during infections. Our findings support the growing body of evidence that medical interventions, such as anti-parasite drugs, induce plastic responses that are adaptive and can facilitate the survival and potentially, drug resistance of parasites. Lay Summary Malaria parasites have evolved flexible strategies to cope with the changing conditions they experience during infections. We show that using such flexible strategies does not impact upon the parasites’ ability to grow (resulting in disease symptoms) or transmit (spreading the disease).

Individual variation affects departure rate from the natal pond in an ephemeral pond-breeding anuran

2008 ◽  
Vol 86 (4) ◽  
pp. 260-267 ◽  
Author(s):  
Nathan D. Chelgren ◽  
Daniel K. Rosenberg ◽  
Selina S. Heppell ◽  
Alix I. Gitelman
Keyword(s):  
Body Size ◽  
Individual Variation ◽  
Environmental Variability ◽  
Pitfall Traps ◽  
Intrinsic State ◽  
Time To Event ◽  
Rana Aurora ◽  
Size At Metamorphosis ◽  
Event Model ◽  
And Behavior

Frogs exhibit extreme plasticity and individual variation in growth and behavior during metamorphosis, driven by interactions of intrinsic state factors and extrinsic environmental factors. In northern red-legged frogs ( Rana aurora Baird and Girard, 1852), we studied the timing of departure from the natal pond as it relates to date and size of individuals at metamorphosis in the context of environmental uncertainty. To affect body size at metamorphosis, we manipulated food availability during the larval stage for a sample (317) of 1045 uniquely marked individuals and released them at their natal ponds as newly metamorphosed frogs. We recaptured 34% of marked frogs in pitfall traps as they departed and related the timing of their initial terrestrial movements to individual properties using a time-to-event model. Median age at first capture was 4 and 9 days postmetamorphosis at two sites. The rate of departure was positively related to body size and to date of metamorphosis. Departure rate was strongly negatively related to time elapsed since rainfall, and this effect was diminished for smaller and later metamorphosing frogs. Individual variation in metamorphic traits thus affects individuals’ responses to environmental variability, supporting a behavioral link with variation in survival associated with these same metamorphic traits.

scholarly journals Life-history traits and the first demographic data of Iranian population of the West Asian Lemon-Yellow Tree Frog, Hyla savignyi (Audouin, 1827)

2021 ◽  
Vol 67 (3) ◽  
Author(s):  
Raziyeh Alaei ◽  
Alireza Pesarakloo ◽  
Masoumeh Najibzadeh ◽  
Sayed Jamal Mirkamali
Keyword(s):  
Life History ◽  
Body Size ◽  
Life History Traits ◽  
Demographic Data ◽  
Size Variation ◽  
Adult Survival ◽  
Lemon Yellow ◽  
Tree Frog ◽  
Size At Metamorphosis ◽  
Hyla Savignyi

The life-history of an organism consists of its lifetime pattern of growth, development, storage, age, and reproduction. In this study, some life-history traits of Hyla savignyi were studied in populations from different parts of Iran. The microscopic and macroscopic analysis showed that testicular activity in H. savignyi is potentially continuous, reaching its peak level in April. Metamorphosis was completed in approximately 102 days after egg deposition, and body size at metamorphosis was 10 mm. Significant sexual size dimorphism was present in all populations, and a larger female asymptotic body size was observed (43.07 mm for females vs 41.16 mm for males). The adult survival rate (S) and life expectancy (ESP) were the same for both sexes (S = 0.73 and ESP = 4.2 years). Age and body size were positively correlated with each other for both females and males. Maximum longevity was recorded to be six years in both females and males, and ages of sexual maturity were estimated to be two or three years in breeding individuals. The adult sample age ranged from two to six years (mean age of females: 4.40±0.68 years; males: 3.63±0.13 years). Our data confirm the general patterns of body size variation and mean age in anurans and show that females are larger than males and live longer.

scholarly journals Adaptive Phenotypic Plasticity for Life History and Less Fitness-Related Traits

2018 ◽  
Author(s):  
Cristina Acasuso-Rivero ◽  
Courtney J. Murren ◽  
Carl D. Schlichting ◽  
Ulrich K. Steiner
Keyword(s):  
Life History ◽  
Phenotypic Plasticity ◽  
Coefficient Of Variation ◽  
Life History Traits ◽  
Meta Analysis ◽  
Adaptive Plasticity ◽  
Variable Environments ◽  
Adaptive Phenotypic Plasticity ◽  
Taxonomic Groups ◽  
Adaptive Nature

ABSTRACTOrganisms are faced with variable environments and one of the most common solutions to cope with such variability is phenotypic plasticity, a modification of the phenotype to the environment. These modifications influence ecological and evolutionary processes and are assumed to be adaptive. The assumption of adaptive plasticity allows to derive the prediction that the closer to fitness a trait is, the less plastic it would be. To test this hypothesis, we conducted a meta-analysis of 213 studies and measured the plasticity of each reported trait as coefficient of variation (CV). Traits were categorised according to their relationship to fitness into life-history traits (LHt) including reproduction and survival related-traits, and non-life-history traits (N-LHt) including traits related to development, metabolism and physiology, morphology and behaviour. Our results showed, unexpectedly, that although traits differed in their amounts of plasticity, trait plasticity did not correlate with its proximity to fitness. These findings were independent of taxonomic groups or environmental types assessed and raise questions about the ubiquity of adaptive plasticity. We caution about generalising the assumption that all plasticity is adaptive with respect to evolutionary and ecological population processes. More studies are needed that test the adaptive nature of plasticity, and additional theoretical explorations on adaptive and non-adaptive plasticity are encouraged.

scholarly journals Naked mole-rat and Damaraland mole-rat exhibit lower respiration in mitochondria, cellular and organismal levels

2021 ◽  
Author(s):  
Kang Nian Yap ◽  
Hoi Shan Wong ◽  
Chidambaram Ramanathan ◽  
Cristina Aurora Rodriguez-Wagner ◽  
Michael D Roberts ◽  
...  
Keyword(s):  
Life History ◽  
Body Size ◽  
Life History Traits ◽  
Molecular Mechanisms ◽  
Biological Significance ◽  
Common Mechanism ◽  
Atp Production ◽  
Mitochondrial Inner Membrane ◽  
Mole Rat ◽  
Similar Body

Naked mole-rats (NMR) and Damaraland mole-rats (DMR) are the only two eusocial mammals known. Both species exhibit extraordinary longevity for their body size, high tolerance to hypoxia and oxidative stress and high reproductive output; these collectively defy the concept that all life-history traits should be negatively correlated. However, when life-history traits share similar underpinning physiological mechanisms, these may be positively associated with each other. Here, we propose that the bioenergetic properties of mole-rats share a potential common mechanism. We adopted a top-down perspective measuring the bioenergetic properties at the organismal, cellular, and molecular level in both species and the biological significance of these properties were compared with the same measures in Siberian hamsters and C57BL/6 mice, chosen for their similar body size to the mole-rat species. We found mole-rats shared several bioenergetic properties that differed from their comparator species, including low basal metabolic rates, a high dependence on glycolysis rather than on oxidative phosphorylation for ATP production, and low proton conductance across the mitochondrial inner membrane. These shared mole-rat features could be a result of evolutionary adaptation to tolerating variable oxygen atmospheres, in particular hypoxia, and may in turn be one of the molecular mechanisms underlying their extremely long lifespans.

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