Changes in the timing of egg-laying of a colonial seabird in relation to population size and environmental conditions

Abstract Background DNA methylation is likely a key mechanism regulating changes in gene transcription in traits that show temporal fluctuations in response to environmental conditions. To understand the transcriptional role of DNA methylation we need simultaneous within-individual assessment of methylation changes and gene expression changes over time. Within-individual repeated sampling of tissues, which are essential for trait expression is, however, unfeasible (e.g. specific brain regions, liver and ovary for reproductive timing). Here, we explore to what extend between-individual changes in DNA methylation in a tissue accessible for repeated sampling (red blood cells (RBCs)) reflect such patterns in a tissue unavailable for repeated sampling (liver) and how these DNA methylation patterns are associated with gene expression in such inaccessible tissues (hypothalamus, ovary and liver). For this, 18 great tit (Parus major) females were sacrificed at three time points (n = 6 per time point) throughout the pre-laying and egg-laying period and their blood, hypothalamus, ovary and liver were sampled. Results We simultaneously assessed DNA methylation changes (via reduced representation bisulfite sequencing) and changes in gene expression (via RNA-seq and qPCR) over time. In general, we found a positive correlation between changes in CpG site methylation in RBCs and liver across timepoints. For CpG sites in close proximity to the transcription start site, an increase in RBC methylation over time was associated with a decrease in the expression of the associated gene in the ovary. In contrast, no such association with gene expression was found for CpG site methylation within the gene body or the 10 kb up- and downstream regions adjacent to the gene body. Conclusion Temporal changes in DNA methylation are largely tissue-general, indicating that changes in RBC methylation can reflect changes in DNA methylation in other, often less accessible, tissues such as the liver in our case. However, associations between temporal changes in DNA methylation with changes in gene expression are mostly tissue- and genomic location-dependent. The observation that temporal changes in DNA methylation within RBCs can relate to changes in gene expression in less accessible tissues is important for a better understanding of how environmental conditions shape traits that temporally change in expression in wild populations.

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

10.21203/rs.3.rs-39315/v2 ◽

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.

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Factors Affecting Egg Deposition of the European Mantis

Folia Biologica ◽

10.3409/fb_68-2.06 ◽

2020 ◽

Vol 68 (2) ◽

pp. 45-49

Author(s):

Joanna Kajzer-Bonk

Keyword(s):

Habitat Selection ◽

Environmental Conditions ◽

Plant Cover ◽

Egg Laying ◽

Natural Conditions ◽

Factors Affecting ◽

Egg Deposition ◽

Predatory Insect ◽

Egg Case ◽

Potential Tool

In this paper, we studied the egg-case (oothecae) deposition of the European mantis, Mantis religiosa (Linnaeus 1758), a predatory insect. We hypothesized that the height of ootheca deposition on a plant reflects the insolation requirements of the species, and would increase when plant cover is denser. We found that the taller the plants nearby, the greater the height of egg deposition. Oothecae were also oviposited higher in denser vegetation. The observed behavior may ensure the proper insolation of developing offspring. To our knowledge, this is the first description of an egg laying strategy of this species under natural conditions. This finding allows for a better understanding of habitat selection and the overall ecology of the European mantis. It may be also useful in identifying the mechanisms of the range extension of this species and is a potential tool to effectively conserve xerothermic ootheca-laying animals. Further studies are required to assess the flexibility of this behavior under different environmental conditions.

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Variations in life history parameters and their influence on rate of population increase of different pathogenic isolates of the pine wood nematode, Bursaphelenchus xylophilus

Nematology ◽

10.1163/156854105774355545 ◽

2005 ◽

Vol 7 (3) ◽

pp. 459-467 ◽

Cited By ~ 22

Author(s):

Yu Wang ◽

Kazuo Suzuki ◽

Daisuke Sakaue ◽

Toshihiro Yamada

Keyword(s):

Life History ◽

Population Size ◽

Botrytis Cinerea ◽

Generation Time ◽

Bursaphelenchus Xylophilus ◽

Egg Laying ◽

Population Increase ◽

Pine Wood Nematode ◽

Life History Parameters ◽

Pine Trees

AbstractTwo virulent isolates and two avirulent isolates of Bursaphelenchus xylophilus and one isolate of B. mucronatus were used to investigate the relationships between life history parameters, rate of population increase and virulence. The results showed that on fungal cultures of Botrytis cinerea, virulent B. xylophilus completed one generation much faster than did avirulent B. xylophilus and B. mucronatus. There was a tendency that virulent B. xylophilus isolates laid more eggs during the egg laying period than did avirulent populations. Shorter generation time and higher fecundity resulted in a higher rate of population increase. Generation time and fecundity were primary factors determining rate of population increase. Difference in rate of population increase is closely related to variation of virulence: virulent B. xylophilus increased population size at the fastest rate, avirulent B. xylophilus was slower, and B. mucronatus was slowest. It is assumed that similar variations in life history parameters and rate of population increase are also expressed in pine trees and help to explain variation of virulence in the field.

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Robustness of the DeLury Population Estimator

Journal of the Fisheries Research Board of Canada ◽

10.1139/f69-034 ◽

1969 ◽

Vol 26 (2) ◽

pp. 339-355 ◽

Cited By ~ 20

Author(s):

Duane O. Braaten

Keyword(s):

Population Size ◽

Environmental Conditions ◽

Random Error ◽

Marked Effect ◽

Simulated Data ◽

Constant Level ◽

Subsequent Increase ◽

Weighted Estimator

This is a study of the robustness, in estimating population size, of the usual DeLury Estimator and three modifications of it derived from the generalized exact deterministic catch equation of Beverton and Holt (1956, 1957). These estimators are called the Generalized DeLury Estimator, the Weighted Generalized DeLury Estimator, and the Effort-corrected DeLury Estimator.A computer was used to simulate varying environmental conditions, which included combinations of several vectors of catchability and effort and several types of random error. The results indicate that the generalized estimator is overall the best, at least for these simulated data. The effort-corrected estimator is just as effective, but requires effort correction. The usual DeLury estimator underestimates on the average. The weighted estimator has high variance.Catchability behavior has a marked effect on accuracy of any of these estimators. An increase in catchability from a previously constant level results in a subsequent increase in the estimate of population size. A decrease in catchability results in a decrease in the estimate. If catchability cycles, the estimate cycles with the same crest and period.Effort has little effect, at least for the vectors studied in this model.

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Nestling Phenology of Anseriformes in the Baikal Siberia Region, Russia

South of Russia ecology development ◽

10.18470/1992-1098-2020-1-145-150 ◽

2020 ◽

Vol 15 (1) ◽

pp. 145-150

Author(s):

E. N. Badmaeva ◽

I. Yu. Deulin ◽

M. A. Gulyaeva ◽

L. D. Bazarov ◽

T. Z. Dorzhiev ◽

...

Keyword(s):

Lake Baikal ◽

Environmental Conditions ◽

Time Frame ◽

Aggregate Data ◽

Egg Laying ◽

Individual Species ◽

Visual Methods ◽

Time Period ◽

Extended Time Period ◽

Species Ecology

Aim. The goal was to aggregate data on the nesting phenology of the range of Anseriformes in the Baikal Siberia region – using the example of Lake Baikal itself.Material and methods. In preparing the materials we used data from our own observations based on foot and car‐based survey assessments and that of other authors for the entire known period of bird research on Lake Baikal, including data from the literature. Standard ornithological visual methods of accounting, registration and description are used.Results. The ecology of Anseriformes nesting has been sufficiently studied, but information on the oviposition phenology is not generalized. During the nesting periods of Anseriformes on Lake Baikal (in particular) the laying of eggs occurs over an extended time period. This prolongation egg‐laying time is normal and is a response to the death of clutches from inundations as well as being a characteristic of some ducks which re‐nest repeatedly. These subsequently lead to a later taking to flight of young birds. Conclusion. The earliest clutches are found among mallard and ruddy shelduck from the end of April, when ponds are still ice‐bound, while the latest are laid up to midJuly by the European widgeon, the white‐winged scoter and the red‐breasted merganser. Mass oviposition of all species occurs in the period from mid‐May to mid‐June. Overall, the egg‐laying period of Lake Baikal Anseriformes lasts from 20 days to 3.1 months. The timing and period of egg‐laying depends on regional environmental conditions and the specifics of individual species’ ecology and biology. Although the general ovipositional time‐frame of Anseriformes regionally is prolonged, the period of mass egg‐laying is quite concentrated and occurs within a period of 20‐30 days.

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Discrimination of Picea chihuahuana Martinez populations on the basis of numerous dendrometric, climatic and edaphic traits and genetic diversity

10.7287/peerj.preprints.2677 ◽

2017 ◽

Author(s):

Iliana Karina Dominguez-Guerrero ◽

Samantha Mariscal-Lucero ◽

José Ciro Hernández-Díaz ◽

Berthold Heinze ◽

José Ángel Prieto-Ruiz ◽

...

Keyword(s):

Genetic Diversity ◽

Discriminant Analysis ◽

Population Size ◽

Environmental Conditions ◽

Diversity Indices ◽

Ex Situ ◽

Assisted Migration ◽

Tree Community ◽

Southern Central ◽

The Mean

Background. Picea chihuahuana, which is endemic to Mexico, is currently listed as “Endangered” on the Red List. Chihuahua spruce is only found in the Sierra Madre Occidental (SMO), Mexico. About 42,600 individuals are distributed in forty populations. The populations are fragmented and can be classified into three distinct clusters in the SMO of the two States (south, center and north), each group separated by a distance of about 300 km. The total area covered P. chihuahuana trees is less than 300 ha. A recent study suggested assisted migration as an alternative to the ex situ conservation of P. chihuahuana, taking into consideration the genetic structure and diversity of the populations and also predictions regarding the future climate of the habitat. However, detailed background information is required to enable development of plans for protecting and conserving species and for successful assisted migration. Thus, it is important to identify differences between populations in relation to environmental conditions. The vitality and genetic diversity of populations, which affect vigour, evolution and adaptability of the species, must also be considered. In this study, we examined the P. chihuahuana tree community growing in fourteen different locations, with the overall aim of discriminating the populations and clusters of this species using 22 climatic, 27 edaphic and 15 dasometric variables and three genetic diversity indices. Methods. Each location was represented by one 50 x 50 m plot established in the center of the location in which was measured the climate, soil, dasometric and genetic variables. The putative neutral and adaptive AFLP were used to calculate genetic diversity. Multivariate discriminant analysis including cross-validation was considered to test for significant differences in variables in the southern, central and northern populations and locations of the P. chihuahuana tree community. Spearman's correlation test was used to analyze the relationships between genetic diversity, population size, and the climatic, soil and dasometric variables. Results. The discriminant analysis revealed 22 highly significant variables, which separated the southern, central and northern populations. The mean genetic diversity of P. chihuahuana was significantly correlated with the mean temperature in the warmest month. Genetic diversity of P. chihuahuana calculated with putative adaptive AFLP was not statistically significantly correlated with any environmental factor. Finally, no significant correlations were observed between any of the three genetic diversity indices and population size. Discussion. At least three different ecotypes of P. chihuahuana probably exist, as local adaptation may take place because of the different environmental conditions. Therefore, future reforestation programs should take into account these different ecotypes and environmental conditions.

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Variasi Karakter Pembungaan Antar Varian dan Ras Lahan Cendana Sepanjang Gradien Geografis di Gunung Sewu

Jurnal Ilmu Kehutanan ◽

10.22146/jik.28282 ◽

2017 ◽

Vol 11 (2) ◽

pp. 173

Author(s):

Yeni Widyana Nurcahyani Cahyaningrum ◽

Sapto Indrioko ◽

Eny Faridah ◽

Atus Syahbudin

Keyword(s):

Genetic Differentiation ◽

Population Size ◽

Environmental Conditions ◽

Extreme Temperature ◽

Conservation Strategy ◽

Floral Display ◽

Flowering Period ◽

Floral Structure ◽

Lower Altitude ◽

Land Races

Cendana merupakan spesies asli Indonesia bagian timur, yang menjadi ras lahan di Gunung Sewu. Sembilan ras lahan di Gunung Sewu, seluruhnya tersusun atas tiga varian yang berbeda struktur dan warna bunganya (MK, merah kecil; MB, merah besar; dan KB, kuning besar). Penelitian ini bertujuan untuk menganalisis karakter pembungaan ketiga varian cendana di Gunung Sewu pada periode pembungaan tahun 2015; di tiga ras lahan yang mewakili tiap zona yaitu Nglanggeran (Zona Utara), Bleberan (Zona Tengah), dan Petir (Zona Selatan). Observasi meliputi fenologi, kemasakan organ reproduksi, display, dan struktur pembungaan. Struktur pembungaan dan longevity organ reproduksi berbeda antar varian. MB dan KB didominasi warna merah dan marun, perigonium lebih besar, organ reproduksi lebih panjang, posisi putik sejajar/lebih rendah dari benang sari, dan longevity lebih singkat. MK didominasi kuning hingga oranye, lebih kecil, posisi putik sejajar/lebih tinggi, dan longevity lebih lama. Display pembungaan berbeda antar ras lahan, namun tidak berbeda antar varian. Petir, dengan ukuran populasi terbesar, memproduksi paling banyak pohon berbunga dan total bunga untuk seluruh varian. Ras lahan dan varian berbunga dua kali setahun, namun dengan inisiasi dan durasi yang berbeda. KB berbunga lebih awal di seluruh ras lahan, sedangkan MB paling akhir. MK memiliki durasi pembungaan terpanjang. Perbedaan antar ras lahan lebih dipengaruhi oleh faktor lingkungan seperti ketinggian, jenis tanah, dan iklim. Ras lahan yang lebih rendah, kering, dan panas berbunga lebih awal dan singkat. Peningkatan temperatur dan turunnya status air tanah menyebabkan keguguran massal yang diikuti sequential replacement, mengakibatkan perubahan frekuensi pembungaan. Strategi konservasi cendana di Gunung Sewu perlu dirancang berbasis keragaman genetik, sinkroni pembungaan, dan kompatibilitas antar varian, dengan tetap mempertimbangkan keberagaman tempat tumbuhnya.Kata kunci: cendana; Gunung Sewu; pembungaan; ras lahan; varian bunga The Flowering Characters Variation Among Floral Variants and Landraces Along Geographical Gradients in Gunung SewuAbstractSandalwood was origin to the south-eastern islands of Indonesia, but is recently occured as new land-races in Gunung Sewu, Java island. All of land-races consisted of three floral variants (MK, refers to “merah kecil”; MB, “merah besar”; and KB, “kuning besar”, respectively). This research aimed to determine flowering of these variants among three of land-races which were representing geographical zone in Gunung Sewu: Nglanggeran, Blebera, and Petir. Observation on phenology, sexual organs maturity, floral structure, and display was conducted in 2015. Floral structures varied among variants. MB and KB dominated by red and maroon colors, possessed bigger perigonium, longer sexual organs but with shorter longevity, and similar/lower position of stylus to stamens. MK dominated by yellow to orange colors, smaller, similar/higher position of stylus, and longer longevity. Floral display varied among land-races but were similar among variants. Petir, with biggest population size, produced the most abundant flowers and flowering trees at all variants. Sandalwood flowered twice a year in all of land-races and variants, however, the onset and duration varied. KB flowered earliest while MB was the latest. MK possessed longest flowering period. Flowering varied among land-races due to the altitude, soils, and climatic differences. Lower altitude, drier, and warmer sites flowered earlier and shorter. Mass abortion and sequential replacement, resulting in the alteration on flowering frequency, occured due to the extreme temperature increment. Conservation strategy should be arranged based on genetic differentiation, flowering differences, and crossing abilities among variants. Differences of landscapes, which may contribute to the differences of environmental conditions and flowering processes, should also be considered.

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The Grey-backed Shrike parents adopt brood survival strategy in both the egg and nestling phases

Avian Research ◽

10.1186/s40657-021-00244-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Liqing Fan ◽

Lifang Gao ◽

Zhenqin Zhu ◽

Xiaodan Zhang ◽

Wen Zhang ◽

...

Keyword(s):

Life History ◽

Environmental Conditions ◽

Decisive Role ◽

Egg Laying ◽

The Tibetan Plateau ◽

Survival Strategy ◽

Size Hierarchy ◽

Brood Survival ◽

Altricial Birds ◽

Parenting Pattern

Abstract Background Great diversity exists in the parenting pattern of altricial birds, which has long been considered as an adaptive response to specific environmental conditions but not to their life-history style. Methods We examined the egg-laying and nestling-raising pattern of the Grey-backed Shrike (Lanius tephronotus) that breeds only once a year on the Tibetan Plateau. We compared the dietary composition to that of its sympatric competitor, the Brown-cheeked Laughing Thrush (Trochalopteron henrici) that breeds twice a year. Results Female Grey-backed Shrikes produced a fixed clutch size of five, with increasing egg size by their laying sequence. The last offspring in the brood is disadvantageous in the size hierarchy because it hatches later. However, they had the largest fledgling body mass. These findings indicate that Grey-backed Shrikes adopt the brood survival strategy in both the egg and nestling phases. Moreover, males and females exhibit no sexual division in providing parental care as they made an equal contribution to the total amount of food delivered to their brood. This parenting pattern of Grey-backed Shrikes, as well as their dietary items, differ significantly from those of the Brown-cheeked Laughing Thrush. Conclusions We suggest that the differentiation in life-history style between sympatric competitors, rather than a behavioral response to specific environmental conditions, plays a decisive role in driving avian parenting strategy diversification.

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THE INFLUENCE OF ENVIRONMENTAL CONDITIONS ON BROOD REARING, BUILD-UP, AND HONEY PRODUCTION OF PACKAGE BEE COLONIES

The Canadian Entomologist ◽

10.4039/ent100127-2 ◽

1968 ◽

Vol 100 (2) ◽

pp. 127-134 ◽

Cited By ~ 2

Author(s):

P. Pankiw

Keyword(s):

Environmental Conditions ◽

Honey Bees ◽

Egg Laying ◽

Complete Darkness ◽

Brood Rearing ◽

Honey Production ◽

Initial Reduction ◽

Bee Colonies

AbstractIn a 5-year study at Beaverlodge, Alta. (lat. 55° N.), 1-kg packages of honey bees hived in mid-April (10–23 April) produced more honey than those hived in early May (5–13 May) in only 2 years. The major nectar flows ranged from 22 June to 22 August.The rate of brood rearing as determined by egg-laying of queens and the build-up as shown by adult bee populations at various periods after hiving increased progressively with delay in hiving dates which ranged from 4 April to 3 May, and were attributed to the more favorable climate of the later hivings. Adult bees in excess of 1 kg per package did not increase egg-laying of queens or the build-up of colonies.Restriction of daylength by 6 hours per day for 8–9 weeks had no effect on colony brood rearing or build-up. Restriction of daylength to 6.5 hours per day for 7 weeks caused a small initial reduction in egg-laying in the first brood cycle (1.5 weeks after hiving) but no differences were noted later, either in egg-laying at 4.5 weeks or adult populations at 9.5 weeks. When colonies were in complete darkness for 3 weeks, egg-laying was reduced 35 to 60%.

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