Timing Of Breeding Research Articles

Effect of dietary energy source on pregnancy rates and reproductive physiology of pastured beef heifers

Proper production of steroid hormones, such as progesterone (P4), is essential for maintenance of pregnancy. Provision of gluconeogenic substrates from the diet may alter postabsorptive energy supplies and associated hormone signaling in a manner supportive of elevating P4 concentrations. Crossbred Angus heifers (n=27) were balanced for pre-trial bodyweight (BW) and body condition score (BCS), then assigned to isoenergetic diets leveraging starch (ES) or fat (EF) as the primary source of energy (45.7% starch vs 11.5% fat). The heifers were placed on the assigned diets 8 days prior to the initiation of estrous synchronization and continued the diets through the second pregnancy diagnosis, 52 days after the initial insemination. On day 28 post-breeding, pregnancy status was diagnosed via ultrasonography. Measurements of follicle size and number were collected via rectal palpation and ultrasonography on days −10, −8, −4, and day 0 relative to breeding. Blood samples were collected on days −10, 1 through 7, 10, 14, 18, 21, 24, and 28 to analyze plasma for P4 concentrations and placental-associated glycoprotein (PAG) concentrations. Data were analyzed using a linear mixed effects model with a fixed effect for treatment and a random effect for pen. Observations collected over time were analyzed using a repeated measures approach with fixed effects for treatment, time, initial condition, and a random effect for pen. Interactions between treatment and pregnancy status were also tested for PAG and P4 concentrations. No treatment differences were observed in final BCS (P=0.12) and total dry matter intake (DMI; P=0.51), though heifers on the ES treatment tended to reach an increased BW (P=0.10). Although heifers fed ES diets had numerically higher conception rates compared to heifers fed EF diets (71.4% vs. 66.7%), there was no statistically significant difference. Furthermore, there were no significant differences observed among diets in terms of pregnancy outcomes, follicle size, or number. A treatment by pregnancy status interaction was detected for both PAG and P4 concentrations. These results suggest that short-term dietary starch supplementation provided around the time of breeding can result in shifts to reproductive hormone abundance that may be conducive for pregnancy establishment.

Census counts of Common Murres adjusted for timing of breeding are more accurate than counts based on calendar dates

Abstract Climate change has resulted in a marked advancement in the breeding phenology of many bird species. Since the timing of many monitoring programs is based on calendar dates, changes in the timing of birds’ breeding seasons may result in a mismatch with the census period. Using data from a long-term population study of Common Murres (Uria aalge; Common Guillemots in Europe) on Skomer Island, Wales, together with simulations, we show that the 2-week advance in the timing of breeding in Common Murres between 1973 and 2020 has serious implications for the timing of census counts. We show that because censuses have traditionally been conducted during the same fixed calendar period each year, the size of the breeding population has been underestimated. We recommend that censuses of breeding seabirds be made relative to the median egg-laying date rather than on specific calendar dates. Since climate change has resulted in a widespread advance in the timing of birds’ breeding seasons in the northern hemisphere, our results may be relevant to Common Murres at other colonies, and to other bird species worldwide.

Cryopreservation of black seabream (Acanthopagrus schlegelii) sperm

In recent years, biotechnology has had a significant impact on the aquaculture industry, particularly in the field of breeding. Molecular selection breeding has emerged as a novel approach to breeding. Reducing the cost of genetic information for individuals with desirable traits after breeding has become an important research direction. Cryopreservation technology allows bypassing time and space constraints in genetic breeding, simplifying broodstock management. This study presents a detailed cryopreservation method for black seabream sperm, evaluating extender type, glucose concentration, cryoprotectant type and concentration, sperm-dilution ratio, and cooling protocols. Sperm motility parameters were analyzed using computer-assisted sperm analysis (CASA) before and after two days of freezing. This involved using an RS solution with a glucose concentration of 15 g/L and adding a 5% final concentration of EG as the sperm cryoprotectant. After mixing the sperm and solution at a ratio of 1:2, we subjected it to 5 min fumigation at 5 cm above the liquid nitrogen surface before plunging it into the nitrogen. Sperm motility reached 85.46 ± 7.32% after two days. Various enzymatic activities showed changes over 20 days post-cryopreservation. This improved cryopreservation protocol for black seabream sperm is beneficial for genetic breeding and reproduction and provides reference for studying the cryodamage mechanisms of black seabream sperm.

DeepMaizeNet: A novel hybrid approach based on CBAM for implementing the doubled haploid technique

AbstractMaize (Zea mays L.) is an important cereal plant in the family of wheatgrass cultivated all over the world. With the increase in human population and environmental factors, the need for maize plants is increasing day by day. One of the efficient methods of increasing production of the maize is maize breeding. The most effective and rapid method for maize breeding is the doubled haploid (DH) technique. This technique reduces maize breeding time and increases productivity. There are different selection methods to select haploid maize seeds in the maize breeding process. Among these selection methods, the most common and most successful selection method is the visual checking of the R1‐Navajo marker. Maize seed separation by hand is a time‐consuming and error‐prone operation. It is labor‐intensive and very tiring; therefore, it is essential to develop a fast and highly accurate intelligent system that separates diploid and haploid maize seeds from each other. This study presents a pioneering approach, introducing the DeepMaizeNet, a hybrid deep learning model that showcases its prowess in accurately classifying haploid maize seeds. The classification of haploid seeds holds significant value for the DH technique, and the proposed model's success is a promising step toward enhanced efficiency. The proposed hybrid model exploits some new techniques such as convolution block attention module, hypercolumn, 2D upsampling, and residual block. For the assessment of the proposed model, the five‐fold cross‐validation technique is employed. The result shows that DeepMaizeNet provides a promising performance by achieving 94.13% accuracy, 94.91% F1‐score, and 97.27% sensitivity.

The phenology and clutch size of UK Blue Tits does not differ with woodland composition

The deciduous tree‐herbivorous caterpillar‐insectivorous bird food chain is a well‐studied system for investigating the impacts of climate change across trophic levels. To date, across Europe, most attention has focused on the impacts of increasing spring temperature on changes to phenology in Oak‐dominated (Quercus spp.) woodlands. Paridae species and Pied Flycatcher Ficedula hypoleuca are the most studied secondary consumers, all of which demonstrate an advancement in reproductive phenology with increases in spring temperature. Shifts in climate and phenology may also impact on reproductive investment in clutch size, and the effects of climate on phenology and clutch size may vary depending on woodland composition. To date, the effects of among‐habitat variation in phenology and reproductive investment have received little attention. Insectivorous birds inhabiting woodlands that differ in tree composition may differ in the timing of breeding, due to local tree leafing phenology acting as a cue for egg‐laying date and/or clutch size. Moreover, for most insectivorous birds, woodland composition within a territory is likely to be the main determinant of food availability for both adults and chicks. Consequently, if warming springs affect the temporal patterns of food availability differently across different woodland compositions, this may affect the optimal average local phenology for nesting birds. Here, using data from 34 long‐term (mean 15 years) nest monitoring sites across the UK, we investigate the effect of woodland tree composition and temperature on Blue Tit Cyanistes caeruleus first egg date (FED) and clutch size. We supplemented the nest monitoring data by quantifying woodland composition, at a site level, through modified point counts. We predict that birds breeding in woodlands with greater proportions of late‐leafing species, such as Oak and Ash Fraxinus excelsior, will breed later than those breeding in woodlands with greater proportions of early‐leafing species, such as Birch Betula spp. and Beech Fagus sylvatica. We found no evidence for differences in Blue Tit FED or clutch size in relation to the proportion of any of the tree species investigated, after controlling for temperature and latitude (FED: −3.4 and 2.2, clutch size: −0.4 and − 0.2 eggs for one‐unit increase in temperature and latitude, respectively). In recent decades and across all sites, clutch size has decreased as spring temperatures have increased, a strategy which could allow birds flexibly to adjust their breeding phenology such that nestling demand coincides with peak food availability. The lack of an effect of woodland composition on Blue Tit phenology suggests Blue Tits do not fine‐tune their reproductive phenology to the local tree composition. Whether this lack of evidence for phenological divergence is due to an absence of divergent selection on breeding phenology and clutch size or to gene flow is not clear.

Analysis of polymorphic variants of MSTN, CAST, PRLR genes associations with economically useful qualities of vyatka breed horses

The relationship of polymorphic variants of MSTN, CAST, PRLR genes with working qualities and body types of Vyatka horses was studied. The purpose of the research is to assess the genetic and breeding potential of the Vyatka breed horses, as well as to study the relationship between the MSTN, CAST, PRLR genotypes and the economically useful qualities of horses. The method of DNA extraction from Vyatka horse hair follicles using ExtraGene DNA Prep. was applied. When scanning the mutations in the loci MSTN (n=43), CAST (n=41) and PRLR (n=41), DNA amplification the method of allele-specific PCR was performed. The frequency of alleles and genotypes was calculated using MS Excel 10. As a result of research, the dependence of Vyatka horses working qualities on the frequency of occurrence of myostatin MSTN alleles (g.66493737 T>C) was noted. The horses with a higher occurrence of the MSTN/C allele have more productive movements than the individuals with the T/T genotype typical for aborigines. Vyatka horses with the T/T genotype are more versatile, and also show better results in sledding, while the horses with the T/C genotype are better under saddle. The horses with the T/T genotype have the highest bony index but the lowest massiveness index. The MSTN T/T (0.581) homozygous genotype for the "wild" allele predominates in Vyatka horses. A relation ship between body types and the calpastatin gene (CAST) has been revealed for the first time in horse breeding. The horses with the G/A genotype turned out to be the most massive and bony, the horses with the A/A genotype were lighter, the highest frequency of occurrence of the CAST G/A genotype (0.463) was noted, the CAST G/G genotype is rare in the breed (0.171). A relationship between the frequency of occurrence of prolactin receptor genes (PRLR) and body types of horses was not found. The frequency of occurrence of PRLR C/C (0.366) and PRLR G/C (0.390) genotypes is approximately identical, the PRLR G/G genotype is less common (0.244). The study of genes associated with economically useful qualities in all breeding stallions will enable to conduct more efficient breeding, using the desired genotypes, which is important for small breeds.

Optimization of the Genetic Transformation System of Lettuce

Lettuce (Lactuca sativa L.) is an annual vegetable crop of the family Asteraceae. It is the most consumed leaf vegetable in the world and is highly valued for its edible and medicinal value. Using transgenic technology, introducing functional genes into plants can shorten the breeding time and improve the quality of lettuce. However, in the genetic transformation of lettuce, the application of transgenic technology is limited by the low conversion rate. In this experiment, using ‘S39’ cotyledons as the test material, to establish a stable genetic transformation system. The results showed that when the leaf regeneration medium was 0.01 mg/L 6-BA and 0.4 mg/L NAA, the highest regeneration rate reached 97.9%, which was the best leaf regeneration hormone concentration. When the infection fluid was used in the OD600 value of 0.2, the infected leaves were in good condition and controllable Agrobacterium was the most suitable infection fluid concentration. When the infection time was 15 min, the infection effect was the best, the leaves grew well, and the resistant plants could grow. The screening in a medium containing 30 mg/L of Kana concentration and 250 mg/L of Cef was the suitable medium formulation. NAA 0.1 mg /L and 6-BA 0.2 mg /L were selected as the optimal concentrations in the rooting medium.

Sex-specific responses to GnRH challenge, but not food supply, in kittiwakes: Evidence for the “sensitivity to information” hypothesis

Seasonal timing of breeding is usually considered to be triggered by endogenous responses linked to predictive cues (e.g., photoperiod) and supplementary cues that vary annually (e.g., food supply), but social cues are also important. Females may be more sensitive to supplementary cues because of their greater role in reproductive timing decisions, while males may only require predictive cues. We tested this hypothesis by food-supplementing female and male colonial seabirds (black-legged kittiwakes, Rissa tridactyla) during the pre-breeding season. We measured colony attendance via GPS devices, quantified pituitary and gonadal responses to gonadotropin releasing hormone (GnRH) challenge, and observed subsequent laying phenology. Food supplementation advanced laying phenology and increased colony attendance. While female pituitary responses to GnRH were consistent across the pre-breeding season, males showed a peak in pituitary sensitivity at approximately the same time that most females were initiating follicle development. The late peak in male pituitary response to GnRH questions a common assumption that males primarily rely on predictive cues (e.g., photoperiod) while females also rely on supplementary cues (e.g., food availability). Instead, male kittiwakes may integrate synchronising cues from their social environment to adjust their reproductive timing to coincide with female timing.

The biotic and abiotic drivers of timing of breeding and the consequences of breeding early in a changing world

Abstract The decision of when to breed is an important determinant of individual fitness. However, despite a multitude of studies investigating the intraspecific relationship between timing of breeding and reproductive performance, less is known about why the strength of this relationship varies between species. Furthermore, environmental change has the potential to alter the relationship between lay date and fitness, but there is still a limited understanding of what mechanisms drive these differential responses to change environmental conditions. We propose that the potential effects of environmental change on the relationship between timing of breeding and fitness are dependent on 2 primary factors: (1) the potential constraints imposed by breeding early and (2) the drivers of higher fitness of early breeders. We first summarize multiple hypotheses proposed to explain why breeding early, either based on absolute date or relative to conspecifics, increases fitness. We then summarize the factors that may constrain when individuals initiate breeding, including limits on the ability to advance their lay date or extend the length of their breeding season under favorable conditions. Understanding constraints on the timing of breeding allows for the identification of obligate (single-brooded species that do not attempt to breed after a specific date) and facultative (predominantly multi-brooding species that have long breeding seasons) early breeding species that are likely differently affected by climate change. Finally, we propose a simple mathematical formula that incorporates the costs and benefits associated with early breeding to quantify how climate change could influence the benefits of early breeding and either mitigate or exacerbate the costs. Our cost-benefit approach provides a clear framework to predict how species may shift the timing of their breeding to maximize fitness in a changing world.

Using culturally significant birds to guide the timing of prescribed fires in the Klamath Siskiyou Bioregion

AbstractHistorically, wildfire and tribal burning practices played important roles in shaping ecosystems throughout the Klamath Siskiyou Bioregion of northern California and southern Oregon. Over the past several decades, there has been increased interest in the application of fire for forest management through the implementation of prescribed fires within habitats that are used by a diversity of migrant and resident land birds. While many bird species may benefit from habitat enhancements associated with wildfires, cultural burning, and prescribed fire, individuals may face direct or indirect harm. In this study, we analyzed the timing of breeding and molting in 11 species of culturally significant land birds across five ecologically distinct regions of northern California and southern Oregon to explore the potential timeframes that these bird species may be vulnerable to wildland fires (wildfire, prescribed fire, or cultural burning). We estimated that these selected species adhered to a breeding season from April 21 to August 23 and a molting season from June 30 to October 7 based on bird capture data collected between 1992 and 2014. Within these date ranges, we found that breeding and molting seasons of resident and migratory bird species varied temporally and spatially throughout our study region. Given this variability, spring fires that occur prior to April 21 and fall fires that occur after October 7 may reduce the potential for direct and indirect negative impacts on these culturally significant birds across the region. This timing corresponds with some Indigenous ecocultural burning practices that are aligned with traditionally observed environmental cues relating to patterns of biological phenology, weather, and astronomy. We detail the timing of breeding and molting seasons more specific to regions and species, and estimate 75%, 50%, and 25% quartiles for each season to allow for greater flexibility in planning the timing of prescribed fires and cultural burning, or regarding the potential implications of wildfires. The results of our study may serve as an additional resource for tribal members and cultural practitioners (when examined within the context of Indigenous Traditional Ecological Knowledge) and forest and wildland fire managers to promote stable populations of culturally significant bird species within fire‐dependent forest systems.

Dexamethasone's effect on endometrial inflammatory response in jennies after artificial insemination with frozen donkey semen

Artificial insemination (AI) with frozen donkey semen leads to low fertility rates in jennies. This might be due to an exacerbation of the acute inflammatory endometrial response to frozen semen, as seen in mares with persistent post breeding endometritis. Higher pregnancy rates were obtained in these mares when treated with dexamethasone at breeding time. The aim of this study was to evaluate the effect of dexamethasone on endometrial inflammatory responses in jennies after AI with frozen donkey semen. This study was performed from August to December 2022 in Argentina. Six healthy jennies of proven fertility were included in a crossover experimental design. All animals passed through an estrous cycle with no treatment before crossover between treatments. Jennies were subjected to 1) no AI and no treatment in estrus (control, C); 2) AI with no treatment (D-); and 3) AI with administration of dexamethasone, 50 mg IV at AI time (D+). Post ovulation. deep AI was performed with frozen donkey semen (700 × 106 progressively motile sperm (PMS). Endometrial samples (cytology and biopsies) were taken at estrus and 24 hours post AI. Cytology smears were stained with Diff-Quick™; 200 cells were counted under an optical microscope (Nikon Eclipse™ NI-U) and the percentage (%) of polymorphonuclear neutrophils (PMN) and eosinophils was calculated.Endometrial biopsies were taken from the bifurcation of the uterine body, fixed in 10% buffered formalin prior to hematoxylin-eosin staining. Five fields were selected per sample at 400x and average cell counts were calculated. The effect of treatments on % PMN and % eosinophils in cytology and biopsies were evaluated by the Kruskal Wallis test followed by the Dunn test for multiple comparisons. Values are expressed as median and interquartile ranges. The cytology smears of all animals showed an inflammatory response to semen deposition. There were differences (P = 0.003) between % PMN in C [0.625 (0.50 - 0.94)] and the other two groups [D-: 35.00 (22.50 - 46.00); D+: 39.50 (28.63 - 40.25)]. No eosinophils were observed. The inflammatory pattern in biopsies showed a diffuse infiltration of PMN and eosinophils in the luminal epithelium, stratum compactum and stratum spongiosum. There were differences (P = 0.003) between % PMN in C [0.30 (0.05 - 0.40) and the other two groups [D-: 41.90 (28.60 - 43.50); D+: 28.70 (10.35 - 49.00)]. Eosinophils were different (P = 0.005) for the three groups [C: 0.40 (0.20 - 1.20); D-: 21.50 (11.35 - 60.60); D+: 4.60 (1.30 - 7.75)]. In conclusion, a single dose of dexamethasone at AI in jennies did not decrease endometrial PMN but decreased eosinophils 24 hours after insemination.

RECORDS OF MOBBING BEHAVIOR IN VENEZUELAN WILD BIRDS

Mobbing is a survival strategy in which birds attack enemies to drive them from the vicinity. This paper reports mobbing behavior events among wild bird species of Venezuela. A total of 31 species from 15 families were recorded in 130 mobbing events. Individual mobbing was the widespread strategy, recorded in 24 species (77%) and 82 mobbing events (63%). Birds tended to mob individually when the enemy was flying but they inclined to do so in groups when the enemy was perched (χ2 =18.191, p<0.05). However, 16 species (52%) required additional assistance of conspecifics, and only three species (10%) were assisted by non-conspecific allies. Anti-predatory was the widespread function, recorded in 27 species (87%) and 106 mobbing events (82%). 22 species (71%) mobbed one bird of prey at least, and 79 mobbing events (61%) were against typical raptor-shaped birds. But mobbing also was performed for other purposes: six species (19%) mobbed for food resource protection in 17 mobbing events (13%) while other four species (13%) mobbed for site defense in five events (4%). Mobbing behavior was recorded at breeding time in 16 species (53%), and 75 mobbing events (58%) occurred at that period. Seven mobber species (23%) were also mobbed. Most mobbing events (98%) were initiated by the weaker species. Highly significant differences were found in body size (W: 4471.0; p>0.01) and body mass (W: 4452.5; p>0.01) between the mobber and mobbed species. In general, a mobber bird engaged in mobbing with other birds of same body size and body mass up to 5.6 times larger and 117.5 heavier. Only the Roadside Hawk Rupornis magnirostris and the Tropical Kingbird Tyrannus melancholichus were exposed to true danger when they mobbed the Great Black-Hawk Buteogallus anthracinus. Recorded information improves the repository of available knowledge in Venezuela and the Neotropical region.

Identification of male-specific DNA markers and generation of genetically all-female offspring using natural pseudomales in Amur catfish (Silurus asotus)

Amur catfish (Silurus asotus) is an economically important species. It demonstrates sexual dimorphism in growth, the females grow faster than the males. Therefore, production of all-female fries for Amur catfish has high commercial potential. However, sex-specific molecular markers are not available for Amur catfish, which hinders the attempt to breed and apply all-female seed for this species. In this study, we established 3 male-specific markers for Amur catfish by restriction-site associated DNA sequencing (RAD-seq) and revealed that Amur catfish has a male heterogametic (XX female, XY male) sex-determination system. Spontaneous pseudomales (individuals that are physiological male and genetic female) were identified from the wild populations of Amur catfish. Genetically all-female larvae for Amur catfish were obtained by crossing the spontaneous pseudomales with the normal females. The male-specific markers for Amur catfish are valuable tools for detecting the genetic sex of the brood fish. Furthermore, generating all-female offspring using natural pseudomales can considerably save the breeding time, which offers a new option for commercial Amur catfish seed production.

094 The impact of temporary or prolonged β-carotene deficiency during the transition period on the preovulatory granulosa cell transcriptomic profile at the time of breeding in dairy cows

094 The impact of temporary or prolonged β-carotene deficiency during the transition period on the preovulatory granulosa cell transcriptomic profile at the time of breeding in dairy cows

Ferruginous Hawk movements respond predictably to intra‐annual variation but unexpectedly to anthropogenic habitats

Birds exhibit flexible movement responses to environmental variation across the annual cycle, and those responses can provide insight into potential impacts that environmental changes may have on these species. To understand year‐round variation in space use by Ferruginous Hawks Buteo regalis, we tracked 12 birds breeding in southwestern Idaho, USA, using GPS telemetry collected over 207 bird‐months. Home‐range sizes of territorial adult hawks showed strong intra‐annual variation, being smallest from April to June and largest from July to October. In contrast, juvenile birds (< 2 years old) did not appear to hold territories and showed no detectable intra‐annual variation in ranging behaviour. Association with land‐cover types by territorial birds varied between breeding and non‐breeding months and was linked to home‐range size. Home‐range sizes of non‐territorial birds were larger than those of territorial birds, and that size did not vary across the year. Association with anthropogenic habitats (irrigated cropland habitats that can provide high rodent densities and increased foraging opportunities) was negatively associated with home‐range size in months of the non‐breeding season. Unexpectedly, the opposite was true in the months of the breeding season, such that use of croplands resulted in larger home‐ranges. Patterns in home‐range size were probably linked to intrinsic factors such as the timing of breeding and migratory behaviour, and to extrinsic factors such as prey availability associated with specific land‐cover types. These results have implications for our understanding of the response of Ferruginous Hawks and other similar species to predicted changes in land cover, and they suggest unexpected relationships between human activity and wildlife behaviour. Furthermore, because the birds we tracked used a large portion of western North America, they are probably relevant far beyond the small area where these individuals were trapped.

Effect of body condition loss in early lactation Holstein cows on plasma IGF-I, prolactin and NEFA during breeding period and its association with some reproductive indices.

The associations between early lactation changes of the body condition score (BCS) and mid-lactation levels of blood insulin like Growth Factor-I (IGF-1), prolactin, insulin, non-esterified fatty acids (NEFA), milk production and some reproductive indices were investigated. Monthly milk yield and BCS were recorded. Blood samples were collected on days 60, 90 and 120 (±5 days) of lactation. Twelve and 17 cows showed BCS losses ≤0.75 and >0.75 on day 60, respectively. BCS losses ≤0.75 till d60 after calving enhanced the IGF-I concentration on d90 (57.8±10.7 vs 35.6±17.8 ng/ml; P=0.001). The differences of blood metabolites were prominent on d90. Trends of insulin changes between d60 BCS (P=0.04) groups were different. Inverse correlations were detected between IGF-I and NEFA (-0.6, P=0.001), IGF-I and milk production (-0.4, P=0.05), NEFA and prolactin (-0.8, P<0.001) on d90. Higher percentages of cows with BCS loss >0.75 (d60) showed their first heat after d40 postpartum. In conclusion, irrespective of BCS at the time of breeding, the level of BCS loss during the first 60 days of lactation may affect further reproductive performance due to prolonged alterations of IGF-I, NEFA, prolactin and insulin levels. The extent of postpartum BCS loss may be a predictor of metabolic status of cows during mid-lactation.

Effective Induction of Fertile Gametes in Oriental × Trumpet (OT) Lily by High Temperatures.

Lily is a very important bulb crop, and interspecific distant hybridization is a crucial method of lily breeding. However, F1 interspecific hybrids tend to be highly sterile due to low levels of genetic homozygosity. This can be addressed by meiotic polyploidization, which has the advantage of reducing breeding time and being able to promote genetic recombination resulting in many variant progenies. High temperatures have been proven to induce 2n gametes via hindering a spindle formation in several plants, but little has been reported in lilies. In the present study, after observing the correlation between the development of the pollen mother cells (PMCs) and the length of the buds, 28-31 mm long buds were selected as the experimental material, which were at the stage of prophase I-metaphase I. Individual buds were induced at different temperatures (40 °C, 42 °C, and 44 °C) and durations (4 h and 6 h) using self-made multiwire heating equipment, and successfully induced fertile male gametes.. The best results were achieved with treatment of 42 °C for 4 h, reaching a maximum fertile pollen induction rate of 36.64%, while bud mortality was 40%. Two chemicals, colchicine and oryzalin, were also used by injection, and only the treatment with oryzalin obtained fertile gametes, with the highest fertile gamete rate of 15.39% at a concentration of 0.005%, while the bud mortality was 36.67%. This suggests that high temperatures have a superior effect on lily 2n gamete induction. In addition, the pollen obtained from the 6 h induction of high temperature was significantly larger than that from the 4 h induction, with an average diameter of 138.64 μm and 107.88 μm, respectively, 2.35 and 1.84 times wider than haploid pollen. The fertile pollen was crossed with four cultivars and two species, and a total of 267 embryonic seeds were obtained, with the highest embryonic rate of 4.52% in OT lily 'Mister Cas' as the parent, which had a germination rate of 26.27%. This suggests that the method of high-temperature induction for fertile gametes probably has important significance for ploidy and distant hybrid breeding in lilies.

Individual variation in the avian gut microbiota: The influence of host state and environmental heterogeneity.

The gut microbiota have important consequences for host biological processes and there is some evidence that they also affect fitness. However, the complex, interactive nature of ecological factors that influence the gut microbiota has scarcely been investigated in natural populations. We sampled the gut microbiota of wild great tits (Parus major) at different life stages allowing us to evaluate how microbiota varied with respect to a diverse range of key ecological factors of two broad types: (1) host state, namely age and sex, and the life history variables, timing of breeding, fecundity and reproductive success; and (2) the environment, including habitat type, the distance of the nest to the woodland edge, and the general nest and woodland site environments. The gut microbiota varied with life history and the environment in many ways that were largely dependent on age. Nestlings were far more sensitive to environmental variation than adults, pointing to a high degree of flexibility at an important time in development. As nestlings developed their microbiota from one to two weeks of life, they retained consistent (i.e., repeatable) among-individual differences. However these apparent individual differences were driven entirely by the effect of sharing the same nest. Our findings point to important early windows during development in which the gut microbiota are most sensitive to a variety of environmental drivers at multiple scales, and suggest reproductive timing, and hence potentially parental quality or food availability, are linked with the microbiota. Identifying and explicating the various ecological sources that shape an individual's gut bacteria is of vital importance for understanding the gut microbiota's role in animal fitness.

Emergence phenology of the giant salmonfly and responses by birds in Idaho river networks

Emergence of adult aquatic insects from rivers is strongly influenced by water temperature, and emergence timing helps to determine the availability of this ephemeral food resource for birds and other terrestrial insectivores. It is poorly understood how spatial heterogeneity in riverine habitat mediates the timing of emergence. Such spatiotemporal variation may have consequences for terrestrial insectivores that rely on aquatic-derived prey resources. We investigated emergence phenology of the giant salmonfly, Pteronarcys californica, at three spatial scales in two Idaho river networks. We examined the influence of tributary confluences on salmonfly emergence timing and associated insectivorous bird responses. Salmonfly emergence timing was highly variable at the basin-scale during the period we sampled (May–June). Within sub-drainage pathways not punctuated by major tributaries, emergence followed a downstream-to-upstream pattern. At the scale of reaches, abrupt changes in thermal regimes created by 10 major tributary confluences created asynchrony in emergence of 1–6 days among the 20 reaches bracketing the confluences. We observed 10 bird species capturing emerged salmonflies, including 5 species typically associated with upland habitats (e.g., American robin, red-tailed hawk, American kestrel) but that likely aggregated along rivers to take advantage of emerging salmonflies. Some birds (e.g., Lewis’s woodpecker, western tanager, American dipper) captured large numbers of salmonflies, and some of these fed salmonflies to nestlings. Emergence asynchrony created by tributaries was associated with shifts in bird abundance and richness which both nearly doubled, on average, during salmonfly emergence. Thermal heterogeneity in river networks created asynchrony in aquatic insect phenology which prolonged the availability of this pulsed prey resource for insectivorous birds during key breeding times. Such interactions between spatial and temporal heterogeneity and organism phenology may be critical to understanding the consequences of fluxes of resources that link water and land. Shifts in phenology or curtailment of life history diversity in organisms like salmonflies may have implications for these organisms, but could also contribute to mismatches or constrain availability of pulsed resources to dependent consumers. These could be unforeseen consequences, for both aquatic and terrestrial organisms, of human-driven alteration and homogenization of riverscapes.

Evolution of seasonal land surface temperature trend in pond-breeding newt (Neurergus derjugini) in western Iran and eastern Iraq

BackgroundTemperature, as one of the effective environmental stimuli in many aspects of species life and ecosystems, can affect amphibians in many ways. Knowing and predicting temperature change and its possible effects on the habitat suitability and movements of amphibians have led many researchers to use climate change scenarios and species distribution models (SDMs). One of the important remote-sensing products that received less attention of conservation biologists is the land surface temperature (LST). Due to the small difference between LST and air temperature, this component can be used to investigate and monitor the daily and seasonal changes of habitats. This study aims to investigate the seasonal trend of LST in the habitat suitability and connectivity of the critically endangered newt (Neurergus derjugini) in its small distribution range, using the MODIS LST time series (2003 to 2021) and with the help of SDMs, Mann–Kendall (MK) and Pettitt non-parametric tests.ResultsIn the last decade, the increasing trend of LST versus its decreasing trends is obvious. Based on MK and Pettitt tests, in the winter and spring, with the decrease in latitude of 35.45° and increase in longitude of 46.14°, the core populations which are located in the southeast have experienced an increase in temperature. Considering the period time of breeding and overwintering, the continuity of winter and spring can be effective on the survival of adult newts as well as larvae in the microclimate. Linkages with the highest current flow between core populations in the winter and summer are the most likely to be vulnerable. At the level of habitat, the increase in LST is proportional to the trend of thermal landscape changes, and all seasons have had an increase in LST, but in winter and summer, the largest area of the habitat has been involved. By continuing the current trend, many high-altitude southern habitats in Iran will be endangered, and the species will be at risk of local extinction.ConclusionThe increasing trend of temperature in all seasons such as winter will affect many adaptations of the species and these effects are mostly evident in the southern parts of its distribution range therefore, captive breeding and reintroduction are recommended for the populations of these areas.