Evaluating the tradeoff between offspring number and survivorship across fishes, amphibians, reptiles and mammals

Oikos ◽  
2021 ◽  
Author(s):  
David M. Anderson ◽  
James F. Gillooly
Keyword(s):  
Offspring Number

Brain size evolution in small mammals: test of the expensive tissue hypothesis

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ying Jiang ◽  
Jia Yu Wang ◽  
Xiao Fu Huang ◽  
Chun Lan Mai ◽  
Wen Bo Liao
Keyword(s):  
Small Mammals ◽  
Brain Size ◽  
Reproductive Investment ◽  
Generalized Least Squares ◽  
Offspring Number ◽  
Size Evolution ◽  
Large Brain ◽  
Species Evolution ◽  
The Cost ◽  
Expensive Tissue Hypothesis

Abstract Brain size exhibits significant changes within and between species. Evolution of large brains can be explained by the need to improve cognitive ability for processing more information in changing environments. However, brains are among the most energetically expensive organs. Enlarged brains can impose energetic demands that limit brain size evolution. The expensive tissue hypothesis (ETH) states that a decrease in the size of another expensive tissue, such as the gut, should compensate for the cost of a large brain. We studied the interplay between energetic limitations and brain size evolution in small mammals using phylogenetically generalized least squares (PGLS) regression analysis. Brain mass was not correlated with the length of the digestive tract in 37 species of small mammals after correcting for phylogenetic relationships and body size effects. We further found that the evolution of a large brain was not accompanied by a decrease in male reproductive investments into testes mass and in female reproductive investment into offspring number. The evolution of brain size in small mammals is inconsistent with the prediction of the ETH.

scholarly journals Evolutionary and ecological perspectives on the wheat phenotype

2021 ◽  
Vol 288 (1958) ◽  
pp. 20211259
Author(s):  
Victor O. Sadras
Keyword(s):  
Precision Agriculture ◽  
Current Model ◽  
Crop Improvement ◽  
Wheat Yield ◽  
High Yield ◽  
Striking Similarity ◽  
Stabilizing Selection ◽  
Grain Number ◽  
Offspring Number ◽  
Trade Offs

Technologies, from molecular genetics to precision agriculture, are outpacing theory, which is becoming a bottleneck for crop improvement. Here, we outline theoretical insights on the wheat phenotype from the perspective of three evolutionary and ecologically important relations—mother–offspring, plant–insect and plant–plant. The correlation between yield and grain number has been misinterpreted as cause-and-effect; an evolutionary perspective shows a striking similarity between crop and fishes. Both respond to environmental variation through offspring number; seed and egg size are conserved. The offspring of annual plants and semelparous fishes, lacking parental care, are subject to mother–offspring conflict and stabilizing selection. Labile reserve carbohydrates do not fit the current model of wheat yield; they can stabilize grain size, but involve trade-offs with root growth and grain number, and are at best neutral for yield. Shifting the focus from the carbon balance to an ecological role, we suggest that labile carbohydrates may disrupt aphid osmoregulation, and thus contribute to wheat agronomic adaptation. The tight association between high yield and low competitive ability justifies the view of crop yield as a population attribute whereby the behaviour of the plant becomes subordinated within that of the population, with implications for genotyping, phenotyping and plant breeding.

scholarly journals The mating rate of Drosophila suzukii reduction due to reproductive interference from Drosophila melanogaster

2020 ◽  
Author(s):  
Yongzhuo Chen ◽  
Min Zhang ◽  
Wei Hu ◽  
Jing Li ◽  
Pengcheng Liu ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Interspecific Competition ◽  
Population Size ◽  
Egg Laying ◽  
Significant Decline ◽  
Reproductive Interference ◽  
Drosophila Suzukii ◽  
Offspring Number ◽  
Successful Mating ◽  
Reproductive Activities

Abstract Background Drosophila suzukii is widely distributed. Research has revealed that the presence of Drosophila melanogaster can reduce the emergence and egg laying of D. suzukii. However, the reasons for these phenomena have not yet been reported. To investigate this issue, we sought to answer three questions: Can the presence of D. melanogaster reduce the longevity of D. suzukii? Does D. melanogaster dominate in larval interspecific competition with D. suzukii? Does reproductive interference occur between these species; i.e., do individuals of one species (e.g., D. suzukii) engage in reproductive activities with individuals of the other (e.g., D. melanogaster) such that the fitness of one or both species is reduced? Results The results showed that the adult offspring number of Drosophila suzukii was significantly reduced when this species was reared with Drosophila melanogaster. The larval interspecific competition had no significant effects on Drosophila suzukii longevity or population size. Surprisingly, Drosophila melanogaster imposed reproductive interference on males of Drosophila suzukii, which led to a significant decline in the rate of successful mating of the latter species. Conclusions The presence of Drosophila melanogaster causes the population size of Drosophila suzukii to decrease through reproductive interference, and the rate of successful mating in Drosophila suzukii is significantly reduced in the presence of Drosophila melanogaster.

scholarly journals Densidade de fêmeas de Trichospilus diatraeae (Hymenoptera: Eulophidae) por pupa de Diatraea saccharalis (Lepidoptera: Crambidae)

2013 ◽  
Vol 13 ◽  
Author(s):  
Elizangela Leite Vargas ◽  
Fabricio Fagundes Pereira ◽  
Vanessa Rodrigues Ferreira Calado ◽  
Daniele Fabiana Glaeser ◽  
Bruna Aparecida Cáceres Rodrigues ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Sex Ratio ◽  
Light Regime ◽  
Climatic Chamber ◽  
Offspring Number ◽  
Diatraea Saccharalis ◽  
Laboratory Conditions ◽  
Glass Tubes

Density of parasitoid females affects their capacity to develop within the host. The number of Trichospilus diatraeae (Hymenoptera: Eulophidae) females per pupa of Diatraea saccharalis (Lepidoptera: Crambidae) was adjusted to study the effect of parasitoid production in the laboratory. Host pupae were parasitised by females of T. diatraeae at densities of 1:1, 7:1, 14:1, 21:1, 28:1 and 35:1 (parasitoid:host). The females of the parasitoid remained in contact with pupae for 24 h in glass tubes (8.5 × 2.5 cm), packed in a climatic chamber regulated at 25 ± 2ºC, 70 ± 10% relative humidity and light regime of 14 h. The percentage of parasitism and emergence of T. diatraeae on pupae of D. saccharalis was 100% in all parasitoid densities. The length of thr cycle (egg-adult) of Trichospilus diatraeae was 19.25 ± 0.22 days at a density of 1:1 and 17.00 ± 0.00 days at 35:1. The offspring number of T. diatraeae was 106.00 ± 12.38 and 514.67 ± 54.55 individuals per pupa at densities of 1:1 and 35:1, respectively. The sex ratio decreased with increasing density, ranging between 0.97 ± 0.01 and 0.89 ± 0.01 at densities of 1:1 and 35:1, respectively. The percentages of parasitism and emergence of T. diatraeae on pupae of D. saccharalis were not affected by the densities of female parasitoids. The densities of 14 to 21 females of T. diatraeae per pupa of D. saccharalis are suitable for rearing this parasitoid under laboratory conditions.

Post-fire species recruitment in a semiarid perennial steppe on the Loess Plateau

2013 ◽  
Vol 61 (1) ◽  
pp. 29 ◽  
Author(s):  
Ling-Ping Zhao ◽  
Gao-Lin Wu ◽  
Zhi-Hua Shi
Keyword(s):  
Loess Plateau ◽  
Fire History ◽  
Seedling Recruitment ◽  
Western China ◽  
The Loess Plateau ◽  
Offspring Number ◽  
Significant Difference ◽  
Species Recruitment ◽  
North Western ◽  
Steppe Community

Offspring recruitment is an important part of population dynamics, as well as for plant-community structure and succession. One generality regarding grasses and fire is that clonal grasses tolerate fire extremely well and in most cases reach their maximum production in the immediate post-fire years. One qualification to this statement is that post-fire offspring, recruitment mode is very important. However, respective data are scare in the semiarid perennial steppe. We studied the relative importance of asexual v. sexual recruitment in the post-fire recovery in semiarid steppe on the Loess Plateau of north-western China. We observed differences in regeneration strategy after different times post-fire (burnt in 2008, burnt in 1999, and no fire history for at least 30 years). Results showed that fire significantly increased offspring recruitment numbers, but not species richness. The increase of asexual recruitment after a fire made a major contribution to the increase of total offspring number. Meanwhile, there was no significant difference for the ratio of asexual to sexual recruitment among sites with different times since fire. The asexual to sexual recruitment ratio was significantly different for different species, with some species not recruiting offspring via sexual recruitment. Our results indicated that seedling recruitment contributed little to post-fire recovery of the perennial-steppe community. Lack of sexual recruitment is not related to fire management but to inherent traits of the occurring plants.

scholarly journals Inbreeding parents should invest more resources in fewer offspring

2016 ◽  
Author(s):  
A. Bradley Duthie ◽  
Aline M. Lee ◽  
Jane M. Reid
Keyword(s):  
General Theory ◽  
Evolutionary Dynamics ◽  
Inbreeding Avoidance ◽  
The Other ◽  
Trade Off ◽  
Offspring Number ◽  
Focal Female ◽  
Special Cases ◽  
Selection For ◽  
Joint Consideration

AbstractInbreeding increases parent-offspring relatedness and commonly reduces offspring viability, shaping selection on reproductive interactions involving relatives and associated parental investment (PI). Nevertheless, theories predicting selection for inbreeding versus inbreeding avoidance and selection for optimal PI have only been considered separately, precluding prediction of optimal PI and associated reproductive strategy given inbreeding. We unify inbreeding and PI theory, demonstrating that optimal PI increases when a female's inbreeding decreases the viability of her offspring. Inbreeding females should therefore produce fewer offspring due to the fundamental trade-off between offspring number and PI. Accordingly, selection for inbreeding versus inbreeding avoidance changes when females can adjust PI with the degree that they inbreed. In contrast, optimal PI does not depend on whether a focal female is herself inbred. However, inbreeding causes optimal PI to increase given strict monogamy and associated biparental investment compared to female-only investment. Our model implies that understanding evolutionary dynamics of inbreeding strategy, inbreeding depression, and PI requires joint consideration of the expression of each in relation to the other. Overall, we demonstrate that existing PI and inbreeding theories represent special cases of a more general theory, implying that intrinsic links between inbreeding and PI affect evolution of behaviour and intra-familial conflict.

scholarly journals Modeling the effect of temperature variability on malaria control strategies

2020 ◽  
Vol 15 ◽  
pp. 65
Author(s):  
Salisu M. Garba ◽  
Usman A. Danbaba
Keyword(s):  
Control Strategies ◽  
Effect Of Temperature ◽  
Bed Nets ◽  
Asymptotically Stable ◽  
Temperature Changes ◽  
Offspring Number ◽  
Local Asymptotic Stability ◽  
Reproduction Numbers ◽  
The Impact ◽  
Disease Free

In this study, a non-autonomous (temperature dependent) and autonomous (temperature independent) models for the transmission dynamics of malaria in a population are designed and rigorously analysed. The models are used to assess the impact of temperature changes on various control strategies. The autonomous model is shown to exhibit the phenomenon of backward bifurcation, where an asymptotically-stable disease-free equilibrium (DFE) co-exists with an asymptotically-stable endemic equilibrium when the associated reproduction number is less than unity. This phenomenon is shown to arise due to the presence of imperfect vaccines and disease-induced mortality rate. Threshold quantities (such as the basic offspring number, vaccination and host type reproduction numbers) and their interpretations for the models are presented. Conditions for local asymptotic stability of the disease-free solutions are computed. Sensitivity analysis using temperature data obtained from Kwazulu Natal Province of South Africa [K. Okuneye and A.B. Gumel. Mathematical Biosciences 287 (2017) 72–92] is used to assess the parameters that have the most influence on malaria transmission. The effect of various control strategies (bed nets, adulticides and vaccination) were assessed via numerical simulations.

scholarly journals The evolution of Daphnia pulex in a temporally varying environment

1998 ◽  
Vol 72 (1) ◽  
pp. 25-37 ◽  
Author(s):  
SAMUEL M. SCHEINER ◽  
LEV Yu YAMPOLSKY
Keyword(s):  
Genetic Variation ◽  
Temperature Change ◽  
Local Population ◽  
Daphnia Pulex ◽  
Selection Response ◽  
Clonal Variation ◽  
Offspring Size ◽  
Malthusian Parameter ◽  
Offspring Number ◽  
Variable Environments

We investigated three aspects of adaptation to variable environments in Daphnia pulex (Cladocera: Crustacea): (1) effects of temporal variation on the evolution of phenotypic plasticity ; (2) plasticity in sexual versus asexual lineages; (3) maintenance of genetic variation in variable environments. We performed a 72-day quasi-natural selection experiment comparing three patterns of variation: constant temperatures, varying but predictable temperature change, and unpredictable temperature change. All populations were begun with an identical array of 34 clones. During selection clonal variation declined in all populations and different patterns of environmental variation had little effect on amounts of genetic variation. Sexual and asexual lineages differed in size and growth rate, but did not differ in amounts of plasticity or in adaptation to variable environments. The primary target of selection was the Malthusian parameter (r) and life history traits of development time, offspring size and offspring number. The heritability of plasticity was generally lower than trait heritability. Because of this difference, the selection response on the mean of the traits overwhelmed the selection response on plasticity. Lower heritabilities of plasticity are very typical, suggesting that our results will be typical of responses to selection in nature. Our results suggest that selection will act mostly on trait means within environments and that plasticity will evolve often as a correlated trait. Because selection on plasticity is based on its across-deme, global fitness, this process will usually be slow. Comparative studies need to shift from closely related, local population differences to those of more distantly related populations or even different species.

scholarly journals Maternal investment in relation to sex ratio and offspring number in a small mammal - a case for Trivers and Willard theory?

2009 ◽  
Vol 78 (5) ◽  
pp. 1007-1014 ◽  
Author(s):  
Esa Koskela ◽  
Tapio Mappes ◽  
Tuuli Niskanen ◽  
Joanna Rutkowska
Keyword(s):  
Sex Ratio ◽  
Small Mammal ◽  
Maternal Investment ◽  
Offspring Number
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