scholarly journals Female variation in allocation of steroid hormones, antioxidants and fatty acids: a multilevel analysis in a wild passerine bird

2018 ◽  
Author(s):  
Lucia Mentesana ◽  
Caroline Isaksson ◽  
Wolfgang Goymann ◽  
Martin N. Andersson ◽  
Monika Trappschuh ◽  
...  

AbstractThe environment where an embryo develops can be influenced by components of maternal origin, which can shape offspring phenotypes and therefore maternal fitness. In birds that produce more than one egg per clutch, females differ in the concentration of components they allocate into the yolk along the laying sequence. However, identification of processes that shape female yolk allocation and thus offspring phenotype still remains a major challenge within evolutionary ecology. A way to increase our understanding is by acknowledging that allocation patterns can differ depending on the level of analysis, such as the populationversusthe among-female (within-population) level. We employed mixed models to analyze at both levels the variation in allocation along the laying sequence of four steroid hormones, three antioxidants, and four groups of fatty acids present in the egg yolks of wild great tits (Parus major). We also quantified repeatabilities for each component to study female consistency. At a population level, the concentrations/proportions of five yolk components varied along the laying sequence, implying that the developmental environment is different for offspring developing in firstversuslast eggs. Females varied substantially in the mean allocation of components and in their plasticity along the laying sequence. For most components, these two parameters were negatively correlated. Females were also remarkably repeatable in their allocation. Overall, our data emphasize the need to account for female variation in yolk allocation along the laying sequence at multiple levels, as variation at a population level is underpinned by different individual patterns. Our findings also highlight the importance of considering both levels of analysis in future studies investigating the causes and fitness consequences of yolk compounds. Finally, our results on female repeatability confirm that analyzing one egg per nest is a suitable way to address the consequences of yolk resource deposition for the offspring.

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Lucia Mentesana ◽  
Caroline Isaksson ◽  
Wolfgang Goymann ◽  
Martin N. Andersson ◽  
Monika Trappschuh ◽  
...  

2012 ◽  
Vol 81 (2) ◽  
pp. 159-162 ◽  
Author(s):  
Petra Hudečková ◽  
Lucie Rusníková ◽  
Eva Straková ◽  
Pavel Suchý ◽  
Petr Marada ◽  
...  

The aim of this study was to compare the effect of two different types of oils in diet on the fatty acid profile in the eggs of layers and to include a particular type of oil as a supplement of feeding mixtures for layers in order to support the development of functional foodstuffs. Thirty layers fed a diet containing soybean oil constituted the control group (soybean oil is the most frequently used oil added to feeding mixtures). In the experimental group (thirty layers), soybean oil was replaced with linseed oil at the same amount (3 kg of oil per 100 kg of feeding mixture). Feeding was provided ad libitum for all days of the month. After one month, egg yolks were analysed and the fatty acid profile was compared. Significant differences (P ≤ 0.05) were found in the concentration of myristic acid that belongs to the group of saturated fatty acids. Eggs in the experimental group showed higher concentrations of myristic acid compared to the control group (0.20 g/100 g of fat and 0.18 g/100 g of fat, respectively). Highly significant differences (P ≤ 0.01) were found for heptadecanoic acid but the trend was opposite to that of myristic acid; concentrations of heptadecanoic acid in the experimental group were lower than those in the control group. Highly significant differences (P ≤ 0.01) were found for n-9 monounsaturated fatty acids where egg yolks in eggs from layers fed linseed oil contained higher concentrations of oleic acid, myristoleic acid, and palmitoleic acid. Lower concentrations of n-6 fatty acids (P ≤ 0.01) were found after the addition of linseed oil in eggs. Linseed oil showed a positive effect on n-3 fatty acids (α-linolenic acid), its concentration in the control and experimental group was 0.82 g/100 g of fat and 5.63 g/100 g of fat, respectively. The possibility of influencing the fatty acid profile in eggs is very important for the development of functional foods.


2009 ◽  
Vol 276 (1663) ◽  
pp. 1845-1854 ◽  
Author(s):  
Arild Husby ◽  
Loeske E.B. Kruuk ◽  
Marcel E. Visser

For multiple-brooded species, the number of reproductive events per year is a major determinant of an individual's fitness. Where multiple brooding is facultative, its occurrence is likely to change with environmental conditions, and, as a consequence, the current rates of environmental change could have substantial impacts on breeding patterns. Here we examine temporal population-level trends in the proportion of female great tits ( Parus major ) producing two clutches per year (‘double brooding’) in four long-term study populations in The Netherlands, and show that the proportion of females that double brood has declined in all populations, with the strongest decline taking place in the last 30 years of the study. For one of the populations, for which we have data on caterpillar abundance, we show that the probability that a female produces a second clutch was related to the timing of her first clutch relative to the peak in caterpillar abundance, and that the probability of double brooding declined over the study period. We further show that the number of recruits from the second clutch decreased significantly over the period 1973–2004 in all populations. Our results indicate that adjustment to changing climatic conditions may involve shifts in life-history traits other than simply the timing of breeding.


1991 ◽  
Vol 332 (1262) ◽  
pp. 91-102 ◽  

The study of allocation of resources offers the possibility of understanding the pressures of natural selection on reproductive functions. In allocation studies, theoretical predictions are generated and the assumptions as well as the predictions can be tested in the field. Here, we review some of the theoretical models, and discuss how much biological reality can be included in them, and what factors have been left out. We also review the empirical data that have been generated as tests of this body of theory. There are many problems associated with estimating reproductive resources, and also with testing how allocation of these resources affects reproductive and other components of fitness, and we assess how important these may be in allowing empirical results to be interpreted. Finally, we discuss the relevance of resource allocation patterns to the evolution of unisexual flowers, both at the level of individual plants (monoecy, andro- and gynomonoecy) and at the population level (dioecy).


2007 ◽  
Vol 274 (1619) ◽  
pp. 1685-1691 ◽  
Author(s):  
Andrew E Fidler ◽  
Kees van Oers ◽  
Piet J Drent ◽  
Sylvia Kuhn ◽  
Jakob C Mueller ◽  
...  

Polymorphisms in several neurotransmitter-associated genes have been associated with variation in human personality traits. Among the more promising of such associations is that between the human dopamine receptor D4 gene ( Drd4 ) variants and novelty-seeking behaviour. However, genetic epistasis, genotype–environment interactions and confounding environmental factors all act to obscure genotype–personality relationships. Such problems can be addressed by measuring personality under standardized conditions and by selection experiments, with both approaches only feasible with non-human animals. Looking for similar Drd4 genotype–personality associations in a free-living bird, the great tit ( Parus major ), we detected 73 polymorphisms (66 SNPs, 7 indels) in the P. major Drd4 orthologue. Two of the P. major Drd4 gene polymorphisms were investigated for evidence of association with novelty-seeking behaviour: a coding region synonymous single nucleotide polymorphism (SNP830) and a 15 bp indel (ID15) located 5′ to the putative transcription initiation site. Frequencies of the three Drd4 SNP830 genotypes, but not the ID15 genotypes, differed significantly between two P. major lines selected over four generations for divergent levels of ‘early exploratory behaviour’ (EEB). Strong corroborating evidence for the significance of this finding comes from the analysis of free-living, unselected birds where we found a significant association between SNP830 genotypes and differing mean EEB levels. These findings suggest that an association between Drd4 gene polymorphisms and animal personality variation predates the divergence of the avian and mammalian lineages. Furthermore, this work heralds the possibility of following microevolutionary changes in frequencies of behaviourally relevant Drd4 polymorphisms within populations where natural selection acts differentially on different personality types.


2012 ◽  
Vol 279 (1749) ◽  
pp. 4885-4892 ◽  
Author(s):  
Marion Nicolaus ◽  
Joost M. Tinbergen ◽  
Karen M. Bouwman ◽  
Stephanie P. M. Michler ◽  
Richard Ubels ◽  
...  

Individuals of the same species differ consistently in risky actions. Such ‘animal personality’ variation is intriguing because behavioural flexibility is often assumed to be the norm. Recent theory predicts that between-individual differences in propensity to take risks should evolve if individuals differ in future fitness expectations: individuals with high long-term fitness expectations (i.e. that have much to lose) should behave consistently more cautious than individuals with lower expectations. Consequently, any manipulation of future fitness expectations should result in within-individual changes in risky behaviour in the direction predicted by this adaptive theory. We tested this prediction and confirmed experimentally that individuals indeed adjust their ‘exploration behaviour’, a proxy for risk-taking behaviour, to their future fitness expectations. We show for wild great tits ( Parus major ) that individuals with experimentally decreased survival probability become faster explorers (i.e. increase risk-taking behaviour) compared to individuals with increased survival probability. We also show, using quantitative genetics approaches, that non-genetic effects (i.e. permanent environment effects) underpin adaptive personality variation in this species. This study thereby confirms a key prediction of adaptive personality theory based on life-history trade-offs, and implies that selection may indeed favour the evolution of personalities in situations where individuals differ in future fitness expectations.


2016 ◽  
Vol 65 (1-2) ◽  
pp. 15-22 ◽  
Author(s):  
Nedeljka Spasevski ◽  
Dušica Čolović ◽  
Slađana Rakita ◽  
Predrag Ikonić ◽  
Olivera Đuragić ◽  
...  

SummaryEggs enriched with n-3 fatty acids and natural pigments are desirable in human food chain due to numerous benefits for health. In this study, we investigated the effects of inclusion of co-extruded linseed and sunflower meal into laying hens’ diet and replacement of synthesized pigment with paprika and marigold flower as sources of natural pigments. Four hundred 18–wk-old Bovan laying hens divided in two groups (control and experiment) were fed for 12 weeks. Fatty acids and β-carotene were monitored every fourth week and successively analyzed. Significantly (p<0.05) increased content of α-linolenic acid in egg yolk in the experimental group in comparison to the control group was observed with addition of linseed, paprika and marigold in laying hens’ nutrition. Nearly the same tendency was observed in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content. Supplementation of the co-extruded linseed and sunflower meal into laying hens’ diet demonstrated significantly (p<0.05) lower n-6/n-3 FA ratio in experimental group compared to control group. The obtained results showed that the synthetic pigment added to laying hens’ diet provided better pigmentation of egg yolks after one and two months of the feeding trial than paprika and marigold flower. The concentration of β-carotene in egg yolks increased in experimental group after three months of the treatment, and that was the first time that concentrations of β-carotene did not significantly (p < 0.05) differ among control and experimental group, which shows that paprika and marigold flower as sources of natural pigments can successfully replace synthetic pigment. We shall continue research in this field with other supplemented mixtures, as there are indices for other potential feed enhancements among oily seeds and herbs.


2017 ◽  
Vol 114 (30) ◽  
pp. 7830-7837 ◽  
Author(s):  
Lucy M. Aplin ◽  
Ben C. Sheldon ◽  
Richard McElreath

Social learning is important to the life history of many animals, helping individuals to acquire new adaptive behavior. However despite long-running debate, it remains an open question whether a reliance on social learning can also lead to mismatched or maladaptive behavior. In a previous study, we experimentally induced traditions for opening a bidirectional door puzzle box in replicate subpopulations of the great titParus major. Individuals were conformist social learners, resulting in stable cultural behaviors. Here, we vary the rewards gained by these techniques to ask to what extent established behaviors are flexible to changing conditions. When subpopulations with established foraging traditions for one technique were subjected to a reduced foraging payoff, 49% of birds switched their behavior to a higher-payoff foraging technique after only 14 days, with younger individuals showing a faster rate of change. We elucidated the decision-making process for each individual, using a mechanistic learning model to demonstrate that, perhaps surprisingly, this population-level change was achieved without significant asocial exploration and without any evidence for payoff-biased copying. Rather, by combining conformist social learning with payoff-sensitive individual reinforcement (updating of experience), individuals and populations could both acquire adaptive behavior and track environmental change.


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