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Variations in day length, or photoperiodism, whether natural or artificial light, significantly impact biological, physiological, and behavioral processes within the brain. Both natural and artificial light sources are environmental factors that significantly influence brain functions and mental well-being. Photoperiodism is a phenomenon, occurring either over a 24 h cycle or seasonally and denotes all biological responses of humans and animals to these fluctuations in day and night length. Conversely, artificial light occurrence refers to the presence of light during nighttime hours and/or its absence during the daytime (unnaturally long and short days, respectively). Light at night, which is a form of light pollution, is prevalent in many societies, especially common in certain emergency occupations. Moreover, individuals with certain mental disorders, such as depression, often exhibit a preference for darkness over daytime light. Nevertheless, disturbances in light patterns can have negative consequences, impacting brain performance through similar mechanisms albeit with varying degrees of severity. Furthermore, changes in day length lead to alterations in the activity of receptors, proteins, ion channels, and molecular signaling pathways, all of which can impact brain health. This review aims to summarize the mechanisms by which day length influences brain functions through neural circuits, hormonal systems, neurochemical processes, cellular activity, and even molecular signaling pathways. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Methods Results Conclusion Northern Japanese children tend to have larger physiques; however, the underlying cause remains unknown. Previous geographical correlation analyses revealed an unusual trend; effective day length was negatively correlated with height and positively correlated with weight (adjusted for height). This paradoxical relationship suggests a thyroid hormone‐like effect and possible photoperiodic response. This study aimed to determine whether this phenomenon remains consistent over time and across different regions of Japan.We used geographically and temporally weighted regression (GTWR) to examine whether the relationship between height and effective day length, which differs from the relationship between weight and effective day length, varies by location and time. GTWR models each observation point separately, allowing for spatial and temporal variations. The analysis included the average height and weight data of children and adolescents by prefecture from 1989 to 2019, along with effective day length considering illuminance above 5000 lx derived from the agrometeorological grid square data.Height was used as the dependent variable, whereas weight and effective day length were used as independent variables. For height estimation, the coefficients of weight and effective day length were consistently positive and negative, respectively, although the regression coefficients showed minor geographical and temporal variations.The opposite correlation between height and effective day length and that between weight and effective day length were consistent. This suggests that the phenomenon is more likely driven by environmental factors than by economic or genetic influences. [ABSTRACT FROM AUTHOR]

Abstract Photoperiod sensitivity affects the rice development cycle and its flowering. Crop simulation models, such as ORYZA (v3), use equations that depend on two main parameters calibrated by the user: sensitivity to photoperiod and minimum optimal photoperiod. Day length, determined by latitude and day of the year, also affects crop development. This study explores the interaction of these parameters in the ORYZA (v3) phenological model. When the optimum minimum photoperiod is shorter than the day length, photoperiod sensitivity delay or inhibit flowering. To ensure a proper simulation, these parameters need to be adjusted to avoid excessive prolongation of the vegetative phase. If calibrated incorrectly, or if let in constant low photoperiod conditions, the plant may remain in the vegetative state. The model presents challenges with cultivars that are highly sensitive to photoperiod in conditions where day length is constantly longer than the ideal minimum photoperiod. This situation may generate uninterpretable results and complicate the calibration of parameters via optimization algorithms. Therefore, it is crucial to properly adjust the optimal minimum photoperiod based on latitude and limit photoperiod sensitivity to ensure accurate and precise simulations of flowering.

Understanding the regulation of flowering time is crucial for adaptation of crops to new environment. In this study, we examined the timing of floral transition and analysed transcriptomes in leaf and shoot apical meristems of photoperiod‐sensitive and ‐insensitive quinoa accessions. Histological analysis showed that floral transition in quinoa initiates 2–3 weeks after sowing. We found four groups of differentially expressed genes in quinoa genome that responded to plant development and floral transition: (i) 222 genes responsive to photoperiod in leaves, (ii) 1812 genes differentially expressed between accessions under long‐day conditions in leaves, (iii) 57 genes responding to developmental changes under short‐day conditions in leaves and (iv) 911 genes responding to floral transition within the shoot apical meristem. Interestingly, among numerous candidate genes, two putative FT orthologs together with other genes (e.g. SOC1, COL, AP1) were previously reported as key regulators of flowering time in other species. Additionally, we used coexpression networks to associate novel transcripts to a putative biological process based on the annotated genes within the same coexpression cluster. The candidate genes in this study would benefit quinoa breeding by identifying and integrating their beneficial haplotypes in crossing programs to develop adapted cultivars to diverse environmental conditions. Summary statement: In this study, we showed for the first time in quinoa that the photoperiod‐driven floral transition initiates at a very early developmental stage, 2–3 weeks after sowing. Moreover, we found different groups of candidate genes, which likely regulate flowering time in quinoa in response to photoperiod and under different photoperiod regimes. [ABSTRACT FROM AUTHOR]

Simple Summary: Day length is a critical environmental factor for gonadal development in animals. However, related studies on male pigs are limited. The present study investigated the effects of different day lengths on behavior changes, growth parameters, testicular size, testosterone secretion, steroidogenesis proteins, and melatonin receptors in Meishan male pigs. The results indicated that a long day length (LDL, 14 h light/10 h dark, 14L/10D) could increase the lying time, decrease the exploring time, and increase the body height, chest circumference, testicular length, testicular weight, crude protein digestibility, and fecal testosterone and cortisol contents compared to a short day length (SDL, 10L/14D) in Meishan male pigs, accompanied by the changes in sex hormone synthesis proteins and melatonin receptor 1b (MT2), but with no change in melatonin receptor 1a (MT1). This suggests that the effect of day length on growth and gonadal development in male pigs may be conducted via MT2 and influence steroid synthesis and secretion in the testis, and proper day length should be provided in male pig breeding. Day length is a critical environmental factor for regulating animal growth and development. This study aimed to investigate the effects of different day lengths on the developmental changes of growth parameters, testicular sizes, testosterone secretion in Meishan male pigs, and steroidogenesis proteins and melatonin receptors. Fourteen Meishan male pigs (10 weeks (wks) of age) with the same parity, paired in litter and body weight (BW), were evenly allocated into a short-day-length group (SDL, 10 light/14 dark) and long-day-length group (LDL, 14 light/10 dark). After 12 wks of the experiment, the LDL-treated boars had more lying time and less exploring time. The LDL treatment led to significant increases in body height, chest circumference, testicular length, testicular weight, crude protein digestibility, and fecal testosterone at the 10th and 12th wks of the experiment, and cortisol at the 10th wk, compared to the SDL treatment, with no differences in the final BW, testicular width, and epididymis weight. Furthermore, the LDL treatment significantly increased the protein levels of melatonin receptor 1b (MT2), aromatase (CYP19), and steroidogenic factor 1 (SF1) in the testis, with no differences in the protein levels of melatonin receptor 1a (MT1), steroidogenic acute regulatory (StAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), and cholesterol side-chain cleavage enzyme (P450scc). The present study suggests that day length has an effect on the growth and gonadal development in male pigs maybe via MT2 and influences steroid synthesis and secretion in the testis. Therefore, proper day length should be considered in male pig breeding. [ABSTRACT FROM AUTHOR]

A biennial sugar beet (Beta vulgaris) generally takes two years to flower and complete its life cycle. In year one, the plant grows vegetatively and then enters a cold winter period. In year two, the plant grows reproductively and initiates flowering under long-day conditions. Among biennial beets that grow vegetatively in outdoor field conditions, two test strains were preliminarily found to flower early under 24-h daylength conditions without being exposed to cold temperatures. To confirm the this phenomenon's genetics, crossings between the test strains and normal biennials yielded hybrid derivatives of F1, F2, and BC1F1, and bolting rate was investigated both in an outdoor field under natural daylength conditions and in a greenhouse with an artificial 24-h daylength. The test strains and hybrid derivatives did not bolt in the outdoor field, similar to the biennial control strains. This enables assessment of important agronomic traits, such as yield, which cannot be evaluated using an annual control strain in which all plants are bolted. However, under 24-h daylength conditions, the test strains bolted without vernalization treatment, unlike the biennial control strains, but similar to annuals. Hybrid derivatives' bolting rates suggest that the flowering characteristics of the test strains are mainly controlled by a single dominant gene. The flowering characteristics and the hypothetical responsible gene were named 'BLOND' and 'Bd', respectively. Because seed production in BLOND is estimated to take at least four months, similar to that of the annual beet, BLOND's bolt rate may be applicable for the speed breeding of sugar beets. [ABSTRACT FROM AUTHOR]

A series of controlled environment treatments were conducted to quantify reproductive development and yield components of Bario Sederhana rice grown under five photoperiod regimes (8, 9, 10, 11, & 12 h). A 'broken-stick' linear regression of heading rate against photoperiod was used to determine the cardinal photoperiods for heading. The reproductive development towards photoperiod showed a delayed pattern in time to heading, anthesis, and maturity under lengthening photoperiod from 10 to 12 h. For example, under 10 h photoperiod the crops required 1680 °Cd (70.8 days) from emergence to heading but took an extended duration of 3147 °Cd (132.6 days) when they were sown at 12 h photoperiod. The prolonged time taken for reproductive development modified by photoperiod resulted in higher yield components. This is because the lengthening time from heading to maturity extended the duration of grain filling. The longest photoperiod of 12 h gave the highest percentage of filled spikelets (65.3%) thus consequently leading to the heaviest grain weight of 1.4 g per panicle. The base, optimum, and maximum photoperiod for heading were estimated to be 7.4 h, 10 h, and 14.8 h, respectively. [ABSTRACT FROM AUTHOR]

IntroductionThe length of the growth period is the key to crop adaptation to new environments. It is strongly affected by the environment in such a way that it is possible to predict the length of the growing period based on some correlations with environmental factors. Simple models that quantify intraspecific variability in flowering responses to temperature and photoperiod can be useful for characterizing lines. Quinoa (Chenopodium quinoa) shows considerable resistance to a wide range of abiotic stresses. Cardinal temperatures and day length at each development stage are necessary to find an appropriate model for predicting plant growth and development.Materials and MethodsTen separate experiments (10 planting dates included: 29 March, 29 April, 28 May, 28 June, 26 July, 23 August, 6 September, 20 September, 29 January, and 29 February) were conducted as randomized complete block design with three replications. The experimental factor consisted of five quinoa lines plus one cultivar (Titikaka). Five promising lines were modified at Yazd Salinity Research Center. Four lines belong to the middle maturing group, one to the late maturing group, and the Titikaka cultivar belongs to early maturing group. The time of beginning and end of each developmental stage, including germination, pollination, and seed maturity, was recorded. The response of developmental stages to temperature and photoperiod was used to determine the cardinal temperature and day length of the main developmental stages (emergence, flowering, and seed maturity).Results and DiscussionBased on the coefficient of determination (R2) it seems that the quadratic model is suitable for estimating the cardinal temperatures of germination, flowering, and ripening of quinoa seeds. Using both quadratic and segmented models to estimate the length of special days resulted to satisfactory robustness. The results showed that on days with a length of lesser than 12 hours and temperatures lesser than 30°C, the flowering rate increased with a simultaneous increase of temperature and day length. As the day length increased to 14 hours, the rate of flowering development changed more significantly when temperatures were between 19 and 25°C than at temperatures below 19°C. For all lines, increasing the day length or temperature resulting in an increased plant maturation rate (from flowering to seed maturity) at a constant temperature or day length. The optimal temperature range for all developmental stages of quinoa lines was between 20 and 25°C. There was a significant difference in the base temperatures of the developmental stages. The base temperature for germination of quinoa lines was above 0°C, the base temperature for flowering was between -2 and +2°C, and the base temperature for seed maturity was below 0°C. The maximum temperature of all quinoa developmental stages was above 40°C (42-51°C). At low temperatures, the flowering stage was more sensitive than the seed ripening stage. The critical day length for flowering and seed ripening of quinoa lines was between 11.5 to 12 hours.ConclusionsThe optimum temperature range for germination was obtained by 25-34°C, for flowering by 28-21°C, and for seed ripening by15-32°C. The optimum temperature of all developmental stages of quinoa lines was between 20 and 25°C. The optimum day length range for flowering is estimated at 11.37-34.12 hours and for seed ripening by 10.58-12.3 hours. Using the segmented and quadratic models to estimate quinoa cardinal temperature and photoperiod response resulted in the same estimations, although in most values, the quadratic model showed a higher coefficient of determination. In general, the results indicated that the temperature and day length have a compensatory effect on the flowering rate and seed ripening stages of the studied lines.

Abstract Background Gut microbiotas play a pivotal role in host physiology and behaviour, and may affect host life-history traits such as seasonal variation in host phenotypic state. Generally, seasonal gut microbiota variation is attributed to seasonal diet variation. However, seasonal temperature and day length variation may also drive gut microbiota variation. We investigated summer–winter differences in the gut bacterial community (GBC) in 14 homing pigeons living outdoors under a constant diet by collecting cloacal swabs in both seasons during two years. Because temperature effects may be mediated by host metabolism, we determined basal metabolic rate (BMR) and body mass. Immune competence is influenced by day length and has a close relationship with the GBC, and it may thus be a link between day length and gut microbiota. Therefore, we measured seven innate immune indices. We expected the GBC to show summer–winter differences and to correlate with metabolism and immune indices. Results BMR, body mass, and two immune indices varied seasonally, other host factors did not. The GBC showed differences between seasons and sexes, and correlated with metabolism and immune indices. The most abundant genus (Lachnoclostridium 12, 12%) and associated higher taxa, were more abundant in winter, though not significantly at the phylum level, Firmicutes. Bacteroidetes were more abundant in summer. The Firmicutes:Bacteroidetes ratio tended to be higher in winter. The KEGG ortholog functions for fatty acid biosynthesis and linoleic acid metabolism (PICRUSt2) had increased abundances in winter. Conclusions The GBC of homing pigeons varied seasonally, even under a constant diet. The correlations between immune indices and the GBC did not involve consistently specific immune indices and included only one of the two immune indices that showed seasonal differences, suggesting that immune competence may be an unlikely link between day length and the GBC. The correlations between the GBC and metabolism indices, the higher Firmicutes:Bacteroidetes ratio in winter, and the resemblance of the summer–winter differences in the GBC with the general temperature effects on the GBC in the literature, suggest that temperature partly drove the summer–winter differences in the GBC in homing pigeons.

The short shoot phenomenon is an important phenotype underlying the economic value of roses – node number can directly affect shoot length. To elucidate the molecular mechanism of how day length affects shoot length, the effect of 8, 10, and 12 h day lengths on node number were studied. The number of nodes between the 8 and 12 h treatment groups significantly differed. Node development in the 12 h treatment group occurred significantly earlier than that in the 8 and 10 h treatment groups and the number of nodes reached a maximum on the third day. Using RNA-seq analysis, we identified candidate genes that regulated shoot length; these were involved in the abscisic acid synthesis pathway and auxin signal transduction and synthesis pathways. Furthermore, the abscisic acid content in the shoot tip decreased with an increasing day length, while the auxin content increased with day length.

A study of global seismic noise during 1997–2022 was carried out. A property of waveforms known as the Donoho–Johnston (DJ) index was used, which separates the values of the wavelet coefficients into "small" and "large". For each reference point in an auxiliary network of 50 points, a time series was calculated with a time step of one day for the median of the values at the five nearest stations. In a moving time window of 365 days, correlations between the index values at the reference points were calculated. A decrease in the average values of the DJ-index and an increase in correlations were interpreted as a sign of an increase in global seismic danger. After 2011, there was a sharp increase in the maximum distances between reference points with large correlations. The high amplitude of the response of the DJ-index to the length of the day for 2020–2022 could predict a strong earthquake in the second half of 2023. The purpose of this study was to improve the mathematical apparatus for assessing the current seismic hazard according to the properties of seismic noise. [ABSTRACT FROM AUTHOR]

Performing migratory journeys comes with energetic costs, which have to be compensated within the annual cycle. An assessment of how and when such compensation occurs is ideally done by comparing full annual cycles of migratory and non-migratory individuals of the same species, which is rarely achieved. We studied free-living migratory and resident barnacle geese belonging to the same flyway (metapopulation), and investigated when differences in foraging activity occur, and when foraging extends beyond available daylight, indicating a diurnal foraging constraint in these usually diurnal animals. We compared foraging activity of migratory (N = 94) and resident (N = 30) geese throughout the annual cycle using GPS-transmitters and 3D-accelerometers, and corroborated this with data on seasonal variation in body condition. Migratory geese were more active than residents during most of the year, amounting to a difference of over 370 h over an entire annual cycle. Activity differences were largest during the periods that comprised preparation for spring and autumn migration. Lengthening days during spring facilitated increased activity, which coincided with an increase in body condition. Both migratory and resident geese were active at night during winter, but migratory geese were also active at night before autumn migration, resulting in a period of night-time activity that was 6 weeks longer than in resident geese. Our results indicate that, at least in geese, seasonal migration requires longer daily activity not only during migration but throughout most of the annual cycle, with migrants being more frequently forced to extend foraging activity into the night. [ABSTRACT FROM AUTHOR]

The current study was conducted in two separate factorial experiments based on completely randomized block design with three replicates and three destructive samples for each replication. The first experiment consisted of two parts. The first part aimed to determine the effect of four photoperiod levels (10‐, 12‐, 14‐, and 16‐h daylight length) on fresh and dry mass, 1000‐seed weight, and seed yield of four ecotypes of Salicornia persica (Gorgan, Central plateau, Urmia, and Bushehr) along with two Salicornia species (S. bigelovii and S. europaea L.). The second part aimed to investigate the chemical properties of the shoots and seeds of Salicornia plants under short‐ and long‐day (10‐ and 16‐h daylight length) photoperiod treatments. The second trial intended to test the eight levels of salinity stress (control, 10, 20, 30, 40, 50, 60, and 70 dS/m with NaCl) on seedling growth traits of three native ecotypes of S. persica (Urmia, Bushehr, and Central plateau) under the best photoperiod treatment resulting from previous experiments (16‐h daylight length). The results showed that fresh mass and dry mass of Salicornia plants are promoted by long days. The maximum values of 1000‐seed weight (0.41 g) and seed yield (7.19 g/plant) were obtained at 16‐h daylight length for S. bigelovii. Nearly in all Salicornia plants, the maximum values of chemical traits were due to exposure to 16‐h daylight length except for seed and shoot flavonoids. In the second experiment, results revealed that S. persica ecotypes positively responded to salinity levels in the range of 10–30 dS/m, while seedling growth was inhibited at 70 dS/m of salinity stress except for S. persica Central plateau. [ABSTRACT FROM AUTHOR]

The timing of entry into freshwater by mature anadromous fishes is an important component of their migration phenology. In iteroparous anadromous species, identifying the migration cues that influence the timing of entry into freshwater, and annual variability in these timings, is important in assessing the extent of individual repeatability. Here, passive acoustic telemetry tracked 71 twaite shad Alosa fallax ('shad') returning to the River Severn's upper estuary over successive spawning seasons, providing individual information on river entry timing and the associated migration cues. The timing of shad returning to the river (defined as their first detection on an acoustic receiver in the upper estuary) was consistent between years and strongly predicted by photoperiod (as increasing day length), whereas water temperatures and flow rates were weak predictors and highly variable between years. Timings of river entry of individual shad were also consistent across consecutive spawning migrations, indicating high individual repeatability. The application of acoustic telemetry in this study thus revealed high repeatability in the timing of annual spawning migrations, which were cued mainly by increasing day length and that, being seasonally predictable, should ensure entry into freshwater with sufficient time to arrive in spawning areas when in-river environmental conditions are favourable. [ABSTRACT FROM AUTHOR]

SUMMARY: Photoperiod effects during the first 7-days posthatch have not been adequately investigated for broiler chicks, especially with modern genetics. Acclimation to the rearing environment (location of feed and water) has historically been the impetus for continuous or near-continuous photoperiods for broilers during the first 7 d. However, recent research has shown that a shorter photoperiod initiated from the day of hatch (20L:4D) does not result in any significant differences in live performance (crop fill, BW, BW gain, FI, FCR) compared to near-continuous lighting (23L:1D). Furthermore, excessive lighting during this critical developmental window may have detrimental physiological effects, which could ultimately inhibit full production potential and decrease overall health and welfare. This study examines the effect of a longer dark phase (scotophase) applied during the first 7-days posthatch on physiological parameters (melatonin, blood glucose, corticosterone). A total of 176 Ross 708 broiler chickens were reared in 2 trials to 7 d of age using 2 different lighting program treatments (20L:4D vs. 23L:1D) applied from day of hatch. Blood sampling was conducted at even intervals during the dark period at d 7. Melatonin production was significantly increased in the 20L:4D group, blood glucose levels maintained a consistent level throughout the dark period for the 20L:4D group, and corticosterone levels were not outside of the normal physiological range for either group. Increased scotophase length implemented as early as day of hatch may result in improved physiological function including growth, health indices, and productivity among others.

Day length is a critical environmental factor for regulating animal growth and development. This study aimed to investigate the effects of different day lengths on the developmental changes of growth parameters, testicular sizes, testosterone secretion in Meishan male pigs, and steroidogenesis proteins and melatonin receptors. Fourteen Meishan male pigs (10 weeks (wks) of age) with the same parity, paired in litter and body weight (BW), were evenly allocated into a short-day-length group (SDL, 10 light/14 dark) and long-day-length group (LDL, 14 light/10 dark). After 12 wks of the experiment, the LDL-treated boars had more lying time and less exploring time. The LDL treatment led to significant increases in body height, chest circumference, testicular length, testicular weight, crude protein digestibility, and fecal testosterone at the 10th and 12th wks of the experiment, and cortisol at the 10th wk, compared to the SDL treatment, with no differences in the final BW, testicular width, and epididymis weight. Furthermore, the LDL treatment significantly increased the protein levels of melatonin receptor 1b (MT2), aromatase (CYP19), and steroidogenic factor 1 (SF1) in the testis, with no differences in the protein levels of melatonin receptor 1a (MT1), steroidogenic acute regulatory (StAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), and cholesterol side-chain cleavage enzyme (P450scc). The present study suggests that day length has an effect on the growth and gonadal development in male pigs maybe via MT2 and influences steroid synthesis and secretion in the testis. Therefore, proper day length should be considered in male pig breeding.

Air temperature and photoperiod play an important role in the seedling development for tropical forest species. Both variables are sensitive to climate, and so evaluating thermal and photoperiodic effects on seedling development is fundamental, especially for climate change studies. Methods to quantify thermal time and the energy required for plants to reach a development stage include air temperature and cardinal temperatures. The photoperiod will also affect physiological reactions of a plant and thus its development. Here we evaluated the six thermal time methods widely used to compute thermal requirement, and identified the influence of the photoperiod from the 2015 and 2016 growing seasons and 12 sowing dates in Itajubá, Minas Gerais state, Brazil, on seedling development of three native tropical forest species Psidium guajava L. (Myrtaceae), Citharexylum myrianthum Cham. (Verbenaceae), and Bixa orellana L. (Bixaceae). The method used to quantify thermal time influenced the analytical results of seedling development; the one that considered three cardinal temperatures and compared them with the mean air temperature (Method 5) performed better in computing thermal requirements. The influence of photoperiod on seedling development was inconclusive for the three species, but all three developed better in mild temperatures (between 13.3 °C and 26.9 °C) with a photoperiod shorter than 13 h. [ABSTRACT FROM AUTHOR]

Songbirds have evolved diverse strategies to cope with seasonality, including long‐, medium‐, and short‐distance migration. There is some evidence that birds with a longer migration distance deposit fuel faster. However, most studies focus on long‐distance migrants. Comparisons between species with different migration distances are necessary to broaden our understanding of fueling capacity in migratory birds. We present maximum fuel deposition rates of five songbird species migrating along the southeast coast of Sweden in autumn with migration distances ranging from long (neotropical migrant) to short (partial/irruptive migrant) (Willow Warbler Phylloscopus trochilus, Lesser Whitethroat Curruca curruca, Common Chiffchaff P. collybita, European Robin Erithacus rubecula, and Blue Tit Cyanistes caeruleus). The birds were fed ad libitum in captivity and were exposed to either extended or natural daylength. All species ceased to increase in mass when they reached a certain fuel load, generally corresponding to migration distance, despite unlimited access to food and ample time for foraging. Blue Tits, Willow Warblers, and Lesser Whitethroats had the highest fuel deposition rates with extended daylength (19%, 20%, and 20%, respectively), and about 13% with natural daylength, which is comparable to the highest rates found in migratory songbirds in nature. European Robins and Common Chiffchaffs that winter in the temperate Mediterranean had the lowest fuel deposition rates (12% and 12% with extended daylength, respectively). Our results suggest that the long‐ and short‐distance migrants in this study have developed an extreme capacity for rapid refueling for different reasons; speedy migration to distant wintering grounds or winter survival in Scandinavia. This study contributes to our current knowledge of maximum fuel deposition rates in different species and the limitations posed by daylength. We highlight the need for future studies of species with different migration strategies in order to draw broad conclusions about fueling strategies of migratory birds. [ABSTRACT FROM AUTHOR]

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Maca (Lepidium meyenii) is a biennial herbaceous plant of the family Brassicaceae, which recently gained research attention as well as consumer interest. Its underground storage organs are used both as a food and as traditional medicine. The storage organs, called fleshy-hypocotyls, are formed by swollen hypocotyl tissues fused with a taproot. The attempts to grow maca outside of its centre of origin have increased globally, although many cropping requirements are unknown. In terms of fleshy-hypocotyl formation, the impact of day length remains unclear. In this study the effects of day length (8 h, 16 h) on early plant development and hypocotyl thickening in yellow maca were investigated in a rhizobox experiment under controlled conditions (20 °C day and 18 °C night temperature, and relative air humidity 25–30%). Results of a 13-week cultivation period showed that number of leaves and leaf length significantly increased in plants grown under long-day (LD, 16 h) conditions as compared to those from the short-day (SD, 8 h) treatment. Furthermore, plants developed under LD conditions had larger hypocotyl width within 67 days after sowing. At 88 days after sowing, the width was almost two-fold higher. Moreover, the total root length of maca plants from LD treatment was significantly longer and had more fine roots (diameter < 0.4 mm) than in plants cultivated in SD treatment. The obtained results suggest that in early stages of plant development LD can stimulate root development and hypocotyl thickening in yellow maca.

On a global scale, soybean (Glycine max (L.) Merr.) is cultivated across a wide range of environmental conditions, characterized by variable temperatures and day lengths. It is important to gather information about different maturity group's phenology and growth patterns to enhance agricultural practices and develop various soybean crop models. We conducted two experiments focusing on soybean maturity groups, commonly used cultivars for early and late maturity groups (one cultivar for each maturity group), one with varying day/night temperatures (22/14, 26/18, 30/22, 34/26, and 40/32°C) under a constant day length of 12.5/11.5 hours. Second, we investigated day lengths of 12.0, 12.5, 13.0, 13.5, 14.0, and 14.5 hours under constant temperature (26°C). We examined various morpho-phenological traits, including plant height, branch number per plant, vegetative development rate, and days to the first flower. Long-day lengths were found to increase the number of branches per plant, whereas shorter-day lengths led to earlier flowering in the cultivars utilized for the experiment. The duration until the first flower was prolonged under lower temperatures and longer day lengths. As a result, understanding the impacts of temperatures and day lengths and their interactions during the leaf, branch, and flowering stages will significantly contribute to improving seed production in future environmental conditions. Furthermore, the insights gained from this study will play an important role in enhancing soybean breeding programs and improving soybean crop models. • Temperature and daylength are major environmental factors deciding soybean growth. • Low temperature and long daylength prolonged the vegetative stage of soybean plants. • Soybean early maturity groups were less sensitive to daylengths for first flowering. • Soybean late maturity groups were more susceptible to temperature and daylength. • Study helps selecting maturity groups, cultivars according to climatic conditions. [ABSTRACT FROM AUTHOR]

Background: Gut microbiotas play a pivotal role in host physiology and behaviour, and may affect host life-history traits such as seasonal variation in host phenotypic state. Generally, seasonal gut microbiota variation is attributed to seasonal diet variation. However, seasonal temperature and day length variation may also drive gut microbiota variation. We investigated summer–winter differences in the gut bacterial community (GBC) in 14 homing pigeons living outdoors under a constant diet by collecting cloacal swabs in both seasons during two years. Because temperature effects may be mediated by host metabolism, we determined basal metabolic rate (BMR) and body mass. Immune competence is influenced by day length and has a close relationship with the GBC, and it may thus be a link between day length and gut microbiota. Therefore, we measured seven innate immune indices. We expected the GBC to show summer–winter differences and to correlate with metabolism and immune indices. Results: BMR, body mass, and two immune indices varied seasonally, other host factors did not. The GBC showed differences between seasons and sexes, and correlated with metabolism and immune indices. The most abundant genus (Lachnoclostridium 12, 12%) and associated higher taxa, were more abundant in winter, though not significantly at the phylum level, Firmicutes. Bacteroidetes were more abundant in summer. The Firmicutes:Bacteroidetes ratio tended to be higher in winter. The KEGG ortholog functions for fatty acid biosynthesis and linoleic acid metabolism (PICRUSt2) had increased abundances in winter. Conclusions: The GBC of homing pigeons varied seasonally, even under a constant diet. The correlations between immune indices and the GBC did not involve consistently specific immune indices and included only one of the two immune indices that showed seasonal differences, suggesting that immune competence may be an unlikely link between day length and the GBC. The correlations between the GBC and metabolism indices, the higher Firmicutes:Bacteroidetes ratio in winter, and the resemblance of the summer–winter differences in the GBC with the general temperature effects on the GBC in the literature, suggest that temperature partly drove the summer–winter differences in the GBC in homing pigeons. [ABSTRACT FROM AUTHOR]

The short shoot phenomenon is an important phenotype underlying the economic value of roses – node number can directly affect shoot length. To elucidate the molecular mechanism of how day length affects shoot length, the effect of 8, 10, and 12 h day lengths on node number were studied. The number of nodes between the 8 and 12 h treatment groups significantly differed. Node development in the 12 h treatment group occurred significantly earlier than that in the 8 and 10 h treatment groups and the number of nodes reached a maximum on the third day. Using RNA-seq analysis, we identified candidate genes that regulated shoot length; these were involved in the abscisic acid synthesis pathway and auxin signal transduction and synthesis pathways. Furthermore, the abscisic acid content in the shoot tip decreased with an increasing day length, while the auxin content increased with day length. [ABSTRACT FROM AUTHOR]

SUMMARY: Lighting programs for broilers have traditionally employed continuous or near-continuous photoperiods through the first week of life to ensure chicks can successfully navigate the rearing environment for feed and water. Normal melatonin production and ocular development require a minimum of 4 h of darkness, yet photoperiod research in broilers has not typically examined the first week. This study examines the effect of a longer dark phase (scotophase) applied during the first 7 d post-hatch on live performance. A total of 384 Ross 708 broiler chickens were reared in 2 trials to 14 d of age using 2 different lighting program treatments (20L:4D vs. 23L:1D) applied from day-of-hatch. No significant differences were observed between treatment groups for live performance parameters including body weight (BW), body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR). Crop fill rates were also assessed, and no significant differences were observed. Increased scotophase length may be implemented as early as day-of-hatch without any compromise in performance.

IntroductionOne of the important factors in the adaptation of plants to new environmental conditions is the appropriate response of development stages to temperature and photoperiod regimes. The thermal time, growing degree days (GDD) or heat unit concept is commonly the basis for modeling phenological development in crop models for different common crops and under-utilized crops. The GDD concept describes crop development as a function of temperature accumulation above the base temperature (lower limit) and in some cases below a cut off temperature (upper limit). Evaluation of plant photoperiod sensitivity is often beneficial help to use appropriate cultivars which in turn to ensure cultivation success. Considering that adaptation of quinoa to new regions demands acclimation to appropriate temperature range also day-length, this study aimed to investigation of quinoa response to Yazd weather condition as an arid region to assess the possibility of quinoa cultivation under these conditions.Materials and MethodsThis research was conducted through 10 separate experiments and were based on a randomized complete block design with three replications. The experimental treatment consisted of five lines (1, 2, 3, 4 and 5), and one cultivar (Titikaka) which belong to different maturing groups including early, middle and late maturing. Ten planting dates selected to be serial as following: March 29, April 29, May 28, June 28, July 26, August 23, September 6, September 20, January 29, and February 29. Every three days, phenological stages of each line including planting distance to each stage of development including emergence, four leaves, flower bud, panicle formation, pollination, seed filling, seed hardening and ripening were recorded accordingly. Using local weather data and equation 1 the needed GDD for every development stage was calculated:GDD= (Tmax-Tmin)/2-T (1)MS-Excel Ver. 15 was employed to arrange recorded data and required calculating. Fitting equations and plotting the graphs were done using Slide Write Ver. 2 and Minitab Ver. 20 software. Results and DiscussionThe results showed that the mean of flowering temperature up to seed formation stage was between 25 and 30 °C for five lines and was between 20 and 25 °C in cultivar 6. The mean length of photoperiod for flowering and seed formation stage of these lines was between 12 and 12.5 hours. The relationship between temperature and day length was inversely related to the number of days of flowering stage, i.e., with decreasing day length and increasing temperature, the number of days for flowering stage was increased. The time required for flowering stage, between 20 to 30° C, for the early maturing cultivar was about 35 days, for the middle maturing lines including 1, 2, 3 and 6 was about 40 days and for the late maturing line 4 was about 45 days. At temperatures higher than 30 °C, a decreasing trend was observed in the number of days required for flowering stage. From the budding stage to the end of the growth period, a significant difference in the GDD was observed for the quinoa lines. The GDD of quinoa was the highest (2530 °C) for late maturing line (4) and was the lowest (1805 °C) for the early maturing cultivar. The effect of planting date on the GDD of quinoa lines showed that moving from March planting date to July, there was an increasing trend on the GDD of quinoa lines and by moving from July planting date to October, a decreasing trend was observed.ConclusionsIn general, quinoa is a short-day plant which is affected by the day length from flowering to seed maturity stages. Line 6 responded qualitatively to day length; however, the other lines responses were quantitatively. The study of the simultaneous effect of temperature and day length showed that temperature has a compensatory effect for day length during flowering stage. According to the results, it seems that the most suitable planting date for early lines suggests in September, for middle maturing lines suggests in August and for late maturing lines suggests in August. The results also showed that line 6 is more suitable than other lines for cultivation in cold regions.

A study of global seismic noise during 1997–2022 was carried out. A property of waveforms known as the Donoho–Johnston (DJ) index was used, which separates the values of the wavelet coefficients into “small” and “large”. For each reference point in an auxiliary network of 50 points, a time series was calculated with a time step of one day for the median of the values at the five nearest stations. In a moving time window of 365 days, correlations between the index values at the reference points were calculated. A decrease in the average values of the DJ-index and an increase in correlations were interpreted as a sign of an increase in global seismic danger. After 2011, there was a sharp increase in the maximum distances between reference points with large correlations. The high amplitude of the response of the DJ-index to the length of the day for 2020–2022 could predict a strong earthquake in the second half of 2023. The purpose of this study was to improve the mathematical apparatus for assessing the current seismic hazard according to the properties of seismic noise.

Blow flies (Diptera: Calliphoridae) are frequently used in forensic investigations due to their rapid colonization of cadavers. As with other insects, environmental temperature strongly influences their developmental rates. While published research has typically explored not only the impact of the environmental temperature, but also of other factors like tissue type and drug presence on developmental rates, the influence of photoperiod on the developmental rates of forensically relevant blow fly species has remained largely underexplored. Understanding the relationship between photoperiod and developmental times is crucial, as neglecting this aspect could compromise the accuracy of minimum post-mortem interval (minPMI) estimations. The present study investigates the impact of three photoperiod conditions (0:24, 8:16, and 12:12 light:darkness) on the developmental rates of Calliphora vicina , focusing on the duration of the different immature stages and on the total developmental time. Our results revealed significant variation in the intra-puparial stage and total development time across different photoperiods. Notably, a 12:12 photoperiod led to a significantly prolonged intra-puparial stage and total development time compared to the 0:24 photoperiod, suggesting that Calliphora vicina develops faster in total darkness. These findings highlight the importance of considering photoperiod in both laboratory rearing protocols and forensic casework to improve the accuracy and reliability of minPMI estimations. In this regard, preliminary guidelines and recommendations are provided. • The photoperiod regime significantly influences the duration of blow fly intra-puparial period. • Consequently, the total developmental time is significantly affected by photoperiod. • Preliminary recommendations on photoperiod for developmental studies are provided. [ABSTRACT FROM AUTHOR]

Maca (Lepidium meyenii) is a biennial herbaceous plant of the family Brassicaceae, which recently gained research attention as well as consumer interest. Its underground storage organs are used both as a food and as traditional medicine. The storage organs, called fleshy-hypocotyls, are formed by swollen hypocotyl tissues fused with a taproot. The attempts to grow maca outside of its centre of origin have increased globally, although many cropping requirements are unknown. In terms of fleshy-hypocotyl formation, the impact of day length remains unclear. In this study the effects of day length (8 h, 16 h) on early plant development and hypocotyl thickening in yellow maca were investigated in a rhizobox experiment under controlled conditions (20 ◦C day and 18 ◦C night temperature, and relative air humidity 25–30%). Results of a 13-week cultivation period showed that number of leaves and leaf length significantly increased in plants grown under long-day (LD, 16 h) conditions as compared to those from the short-day (SD, 8 h) treatment. Furthermore, plants developed under LD conditions had larger hypocotyl width within 67 days after sowing. At 88 days after sowing, the width was almost two-fold higher. Moreover, the total root length of maca plants from LD treatment was significantly longer and had more fine roots (diameter < 0.4 mm) than in plants cultivated in SD treatment. The obtained results suggest that in early stages of plant development LD can stimulate root development and hypocotyl thickening in yellow maca. [ABSTRACT FROM AUTHOR]

Diel vertical migration (DVM) is common in zooplankton populations worldwide. Every day, zooplankton leave the productive surface ocean and migrate to deepwater to avoid visual predators and return to the surface at night to feed. This behavior may also help retain migrating zooplankton in biological hotspots. Compared to fast and variable surface currents, deep ocean currents are sluggish, and can be more consistent. The time spent in the subsurface layer is driven by day length and the depth of the surface mixed layer. A subsurface, recirculating eddy has recently been described in Palmer Deep Canyon (PDC), a submarine canyon in a biological hotspot located adjacent to the West Antarctic Peninsula. Circulation model simulations have shown that residence times of neutrally buoyant particles increase with depth within this feature. We hypothesize that DVM into the subsurface eddy increases local retention of migrating zooplankton in this feature and that shallow mixed layers and longer days increase residence times. We demonstrate that simulated vertically migrating zooplankton can have residence times on the order of 30 days over the canyon, which is five times greater than residence times of near‐surface, nonmigrating zooplankton within PDC and other adjacent coastal regions. The potential interaction of zooplankton with this subsurface feature may be important to the establishment of the biological hotspot around PDC by retaining food resources in the region. Acoustic field observations confirm the presence of vertical migrators in this region, suggesting that zooplankton retention due to the subsurface eddy is feasible. Plain Language Summary: Diel vertical migration (DVM) is considered the world's largest migration by biomass. Zooplankton migrate into the sea's surface waters to feed at night when risk of predation by visual predators is low. During the day, zooplankton migrate to deeper waters when risk of predation by predators like seabirds and fish is highest. This behavior may also retain zooplankton in areas of high biological activity, or hotspots. Migration between a rapidly moving surface layer and a sluggish subsurface layer may reduce the net horizontal movement of organisms. Since this behavior is modulated by light intensity, more daylight hours may increase the time spent in the slower subsurface layer and help retain zooplankton in these hotspots. We used simulated zooplankton in a numerical model over Palmer Deep Canyon to test how DVM behavior, and the factors that control the time spent in the subsurface layer, affects zooplankton retention within biological hotspots. Retention was highest for zooplankton when migrations were deepest, days were long, and surface mixed layer was shallow. Performing migrations also increased retention relative to near‐surface nonmigrating zooplankton. Acoustic observations within our study site suggest that the magnitudes of DVM simulated are feasible in this system. Key Points: Simulated diel vertical migrating zooplankton have increased residence time compared to nonmigrators near a biological hotspotShallow surface layers and long days lead to longer residence times of simulated diel vertical migrating zooplanktonField acoustic measurements show the presence of zooplankton diel vertical migration consistent with simulated migration [ABSTRACT FROM AUTHOR]

LED lights can be used to increase the length of garlic plants that require a day length of more than 12 hours because it can help the photosynthesis process as a substitute for sunlight. This study aimed to determine the effect of increasing the length of illumination using white LED lights 100-watt with an intensity of 9685±385 lux on the growth and yield of garlic. The experiment was carried out from May to September 2021 in Balitsa Lembang, West Java. The experimental design was a split block design. The first factor is the addition of illumination length, namely 3 hours, 5 hours, 7 hours, and control. The second factor was variety, namely Lumbu Hijau and Tawangmangu Baru. The results showed that the addition of 5 hours of illumination to the Tawangmangu Baru was able to increase plant height, plant crown weight, and clove width. The addition of 3, 5, and 7 hours of illumination had no significant effect on plant height, the number of leaves, stem diameter, SPAD index, leaf area, specific leaf area, biomass, tuber weight, tuber diameter, and clove size of Lumbu Hijau. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether there is an association between season, temperature, and day length at oocyte retrieval and/or embryo transfer (ET) and clinical outcomes in frozen ET cycles.Design: Retrospective cohort study.Setting: Large academically affiliated research hospital.Patient(s): A total of 3,004 frozen ET cycles from 1,937 different women with oocyte retrieval and transfer between 2012 and 2017.Intervention(s): None.Main Outcome Measure(s): Implantation, clinical pregnancy, spontaneous abortion, and live birth.Result(s): Frozen ETs with oocyte retrieval dates in summer had 45% greater odds of clinical pregnancy (odds ratio [OR], 1.45; 95% confidence interval [CI], 1.15-1.82) and 42% greater odds of live birth (OR, 1.42; 95% CI, 1.13-1.79) compared with those with oocyte retrieval dates in winter. A 41% greater odds of clinical pregnancy (OR, 1.41; 95% CI, 1.16-1.71) and 34% greater odds of live birth (OR, 1.34; 95% CI, 1.10-1.62) were observed among transfers with an average temperature at oocyte retrieval in the highest tertile (17.2-33.3 °C) compared with those in the lowest tertile (-17.2-6.7 °C). There were no consistent associations between clinical outcomes and day length at oocyte retrieval or between season, day length, or temperature at transfer of thawed embryos.Conclusion(s): Warmer temperatures at oocyte retrieval are associated with higher odds of clinical pregnancy and live birth among frozen ET cycles. The consistent associations seen with oocyte retrieval dates and the lack of associations observed with ET dates suggest that any seasonality effects on in vitro fertilization success are related to ovarian function and not uterine receptivity. [ABSTRACT FROM AUTHOR]

The review analyzes the available literature data on the seasonal development of plant bugs of the subfamily Phylinae distributed in the Holarctic Region. The data set concerns 39 species from 3 tribes: Pilophorini, Hallodapini, and Phylini. The tribe Pilophorini is represented by 5 species, 3 of which complete one generation per year and hibernate at the egg stage. However, there is no reason to believe that their annual cycles are obligatory univoltine, since they have been studied only in regions with a relatively cold climate. Two other species of this tribe, Pilophorus confusus and P. typicus, are multivoltine in regions with a warmer climate (Spain and Japan, respectively), where they also overwinter at the egg stage. The data on 3 species of the tribe Hallodapini indicate that they have similar seasonal cycles with a single generation per year and overwintering at the egg stage. The greatest diversity of seasonal patterns is known in the tribe Phylini. Two out of 5 Chlamydatus species included in this review overwinter as adults, although overwintering at the egg stage is generally characteristic of the family Miridae. Three species of this genus have a multivoltine seasonal cycle, and no data are available on the voltinism and overwintering stage of two other species, Ch. allii and Ch. wilkinsoni. Of the remaining 26 species of the tribe Phylini, 6 species have a multivoltine seasonal cycle and complete from 2 to 4 generations per year in different climatic zones. The bivoltine Campylomma verbasci from the same tribe has a seasonal adaptation unusual for true bugs, namely the shift of host plants during the year realized by different generations: after overwintering, the bugs move from woody plants to herbaceous ones. In general, the subfamily Phylinae is very species-rich and has highly diverse ecological characteristics, such as trophic specialization, voltinism, overwintering stage, seasonal shift of host plants, wing polymorphism, etc. [ABSTRACT FROM AUTHOR]

Seasonal reproductive cycles of most birds are regulated by photoperiod via neuroendocrine control. The present study aims to investigate the role of a single long day in triggering hypothalamic expressions of GnRH-I and GnIH in the Eurasian tree sparrow (Passer montanus). Sparrows were divided into two groups (n = 24 each) and pre-treated under short days (9L: 15D) for 4 days. On the fifth day, one group was exposed to long day (14L: 10D), while other was continued under short day for another 1 day. Birds of both the groups were sacrificed and perfused on fifth day at different time points, i.e., ZT 14, ZT 16 and ZT 18 and the expressions of GnRH-I and GnIH mRNAs and peptides were studied using real-time PCR and immunohistochemistry, respectively. In addition, testicular size was measured to know testicular development. Observations revealed that birds exposed to a single long day (14L: 10D) showed an increase in hypothalamic expressions of GnRH-I mRNA and peptide and decrease in levels of GnIH mRNA only at ZT 16 and ZT 18 with no significant change in GnIH peptide. However, no significant change in GnRH-I or GnIH expression was observed at any time point under short day and birds maintained high and low expression levels of GnIH and GnRH-I, respectively. Our results clearly indicate that the photoperiodic response system of sparrow is highly sensitive to light and responds even to single long day. Furthermore, they suggest that the GnRH-I and GnIH are expressed in the hypothalamus of tree sparrow in an anti-phasic manner and switching over of their expression occurs at late hours of exposure of birds to single long day. [ABSTRACT FROM AUTHOR]

Effects of the interaction between lighting programme and dietary protein content on broiler performance and meat yield were investigated. The hypothesis was that low breast meat yield from birds managed under short day lengths could be improved by increasing dietary protein content. The treatments consisted of four lighting programmes and four dietary protein levels. They were applied to sexed broilers from one day old to 35 days old. Eight light-tight rooms each contained eight pens with 50 birds, sexes separate, in each pen. Each feed x sex treatment was replicated twice in each room, with the four lighting treatments also being replicated twice. Multiple regression analysis was used to measure responses to the three factors. There was no significant interaction between dietary protein content and lighting programme in feed intake, feed conversion efficiency, bodyweight gain, carcass chemical composition and breast meat yield. Breast meat yield was linearly related to the number of hours of light, the highest yield occurring on the longest day length. Food intake was the same on the shortest day length and the longest, yet breast meat yield was greater on the 23-hour light programme. The decreased breast meat yield in broilers given short day lengths was therefore not the consequence of a shortage of dietary protein, and this hypothesis therefore had to be rejected. [ABSTRACT FROM AUTHOR]

Implementing a photoperiod during incubation has been shown to be a potential next step to removing one more stressor for newly hatched poultry species. The distribution of hatch over time is a parameter that may be influenced by photoperiod that could benefit from a photoperiod but has not been studied at this time and is the objective of this paper. The impact on hatch rate for three strains of chicken, Barred Plymouth Rock (BR), Lohmann Brown (LB) and Lohmann Lite (LL), was measured following the provision of a 12L : 12D (12 h light : 12 h dark) photoperiod starting at 0, 9 or 17 days of incubation and compared with incubation in the dark. The cumulative number of chicks hatched eggs at four points in time (489, 498, 507 and 516 h of incubation) was analysed using repeated measures analysis in a 3 × 4 factorial arrangement of treatments. Repeated measures analysis was done to determine the main and interaction effects of photoperiod and bird strain, and a regression analysis was used to determine how these effects evolved over time. Lohmann Brown embryos provided a 12L : 12D photoperiod throughout incubation were first to reach 50% of total chicks hatched and rate of hatch from 50% to 75% of total chicks hatched as well. As the LB chicks did not begin to hatch earlier or finish later, the LB strain was the most synchronised when provided a 12L : 12D photoperiod from the beginning of incubation. Similar results were found for LL, but no difference on the percentage hatched over time was found when provided the 12L : 12D photoperiod at the beginning of incubation or at day 9. The BR strain only showed a significant difference in hatch window synchronisation when provided a 12L : 12D photoperiod at day 9 of incubation. These results indicate that the strain of chicken impacts the hatch window, and each strain responds to a photoperiod during incubation differently. This information could be useful for hatchery managers to deal with different strains of chicken for incubation.

Understanding cues for diapause termination in insects can be valuable in predicting phenological events in their lifecycles. Once identified, such cues can be utilized as a biofix, the point at which the majority of individuals within a population begin to accumulate degree days. We investigated the impact of photoperiod on completion of reproductive diapause in the invasive eastern North American population of the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), by exposing diapausing females to varying light regimes in otherwise identical environments. The critical photoperiod estimated to initiate reproductive development in at least 50% of the potential reproductive population was 13.0–13.5 h, with increasing photoperiods coinciding with increased probability of females reproducing, earlier time to first oviposition, and higher rates of fecundity. These data on the species' response to photoperiod are in agreement with previous modeling that predicted the twin constraints of photoperiod and temperature on H. halys reproduction prevents populations that undergo diapause from producing more than two generations annually anywhere within the continental U.S. However, the facultative nature of diapause in H. halys leaves open the possibility that sub-populations may not enter diapause in some conditions, potentially allowing for additional annual generations. [ABSTRACT FROM AUTHOR]

The paper reviews the available data on seasonal development of the best studied species of the subfamily Orthotylinae inhabiting the Palaearctic and Nearctic regions and included in 2 of the 6 tribes of this subfamily: Halticini and Orthotylini. All the 12 species of the tribe Halticini studied to date and included into this review are phytophagous with a wide range of host plants; all of them are characterized by wing polymorphism with long-winged males and, as a rule, short-winged females. Of these 12 species, 11 have a univoltine seasonal cycle and overwinter at the embryonic stage. When a species with a univoltine seasonal cycle penetrates beyond its native range, its seasonal development pattern remains close to the original one adapted to the environmental conditions of the species' native range. Microtechnites bractatus stands apart in the tribe Halticini because it represents the only genus in this tribe in which all the species are restricted to the Western Hemisphere, have a multivoltine seasonal cycle, and are zoophytophagous. Almost all the species of the tribe Orthotylini, regardless of their geographic distribution, have a univoltine seasonal cycle and are zoophytophagous, with the exception of Orthotylus flavosparsus, which has a multivoltine seasonal cycle and is phytophagous, preferring plants of the subfamily Chenopodioideae throughout most of its Holarctic range. Analysis of the data indicates that the seasonal development of Orthotylinae is still poorly understood, although among them there are many species that have great economic importance and invasive potential. [ABSTRACT FROM AUTHOR]

• In a subtropical climate, photoperiod manipulation allows two crops of hops a year. • Photoperiod extension with LED (>16.9 hr, <1 µmol m–2 s–1) inhibits flowering in hops. • Hop yield and quality vary between spring and fall seasons in the subtropics. • Hops have high phenological plasticity with no chilling requirement for bud break. Hops (Humulus lupulus L.) have an ancient history of cultivation in temperate climates primarily as an ingredient of beer. However, growing hops in subtropical or tropical climates has been challenging because of non-optimal day length conditions. We examined the potential of subtropical hop production with photoperiod manipulation. 'Cascade' hops were grown in Florida, United States with extended day length (>16.5 h) using light-emitting diode (LED) bulbs to inhibit flowering until sufficient vegetative growth was achieved. Phenology, plant growth, yield, and cone quality data were collected during the first two years after planting. With as little as 0.47 μmol m–2 s–1, photoperiod extension was effective in inhibiting flowering, while promoting vegetative growth. Uniform flowering was induced upon the discontinuation of photoperiod extension. As a result, plants achieved two growing cycles per year, with the spring and fall growing seasons running from February to July and July to December, respectively. Yield increased by 92 % from Year 1 to Year 2 but decreased by 37 % from the spring to fall growing season. The maximum yield was 465 kg ha–1 in Year 2 Spring. Cone quality was greatly affected by both year and season, with α acid, β acid, and total oil concentrations ranging from 2.7 % to 6.2 %, 1.9 % to 3.2 % and 0.14 to 0.53 mL/100 g, respectively. These results demonstrate that, with an aid of photoperiod manipulation for flowering control, 'Cascade' hops exhibit high phenological plasticity and acclimation capacity to subtropical climatic conditions. This study provides a foundation for developing the double-season hop production system in a subtropical climate. [ABSTRACT FROM AUTHOR]

Abstract Background Heading time is an important trait for regional and seasonal adaptabilities in rice, and is controlled by genetic factors in relation with environmental factors, mainly day length and temperature. The following genes controlling heading were examined for their responses to six different environmental conditions involving different day lengths using five early near-isogenic lines (NILs) of T65-R and three late NILs of T65wx: two earliness genes, Ef1 and Efx controlling basic vegetative phase (BVG), and m-Ef1, the enhancer to the former gene; and two lateness genes, Se1-pat(t) and se-pat controlling photo-sensitivity and BVG, respectively. T65-R and T65-T were different accessions of Taichung 65. T65wx is a NIL of T65-T carrying wx. Results The five early NILs of T65-R were in the order of ER50 (Ef1, Efx, m-Ef1)

The seasonal adaptations of 8 better studied species belonging to 4 genera of the tribe Stenodemini are analyzed. A univoltine seasonal cycle with obligate diapause is characteristic of four studied species: Stenodema calcarata, S. laevigata, Leptopterna dolabrata, and L. ferrugata. Species of the genus Stenodema have winter adult diapause, whereas both species of the genus Leptopterna overwinter at the egg stage. In the remaining four species (Notostira elongata, N. erratica, Trigonotylus caelestialium, and T. tenuis) the seasonal cycle is multivoltine; in different climatic zones these species can complete from 1 to 5 generations per year, depending on the climatic conditions, and overwinter in the state of adult (Notostira spp.) or embryonic (Trigonotylus spp.) diapause. Induction of winter diapause is controlled by the photoperiodic response, which is well studied in species of the genus Trigonotylus. Under long-day conditions females lay non-diapausing (i.e., directly developing) eggs, whereas under short-day conditions they produce diapausing eggs. Cases of wing and color polymorphism are known in Stenodemini. For instance, high temperature and crowding during development of older nymphs (IV and V instars) of L. dolabrata were shown to promote the appearance of long-winged females, whereas short-winged females usually predominate in the wild; males of this species are always long-winged. Body color polymorphism in species with a univoltine seasonal cycle (Stenodema spp.) appears as the body color change of the overwintering individuals from russet-brown in autumn to bright green in spring. In multivoltine species (e.g., Notostira elongata), alternative color forms are associated with different generations: adults of the summer generation have a bright grassy body color while females of the overwintering generation are russet-brown; males do not overwinter. The example of Trigonotylus caelestialium convincingly demonstrates that the nutritional factor can have an independent value in the induction of diapause. The ability of females to produce simultaneously directly developing and diapausing eggs in the middle of summer, at high temperatures and a long day, may be considered an adaptive strategy allowing at least a part of the future offspring to survive under the conditions of unstable food supply. In general, a review of data on the seasonal development of true bugs of the tribe Stenodemini, as well as of the previously studied tribe Mirini, indicates poor knowledge of even the economically important species of plant bugs (Miridae). These data provide only a general view of the seasonal adaptations and annual cycles characteristic of species of the subfamily Mirinae. [ABSTRACT FROM AUTHOR]

This ecological study examined whether geographical differences in the physique of Japanese children and adolescents can be explained from the perspective of photoperiodicity induced by effective day length (light duration exceeding a certain threshold of illuminance) using prefecture-level anatomical data and Mesh Climatic Data. Multiple regression analysis for height prediction demonstrated that when controlled by weight, effective day lengths of the longest and shortest months were inversely correlated with height distribution. Conversely, for weight prediction, when controlled by height, the effective day lengths of the longest and shortest months were positively correlated with weight distribution. The regression coefficients were greater for the effective day length of the shortest month in both height and weight prediction. This phenomenon where the same two explanatory variables are negatively correlated with height and positively correlated with weight in a significant manner is rare, and there may be no physiological interpretation of this phenomenon other than one based on changes in thyroid hormone signaling. These distribution characteristics are common to the photoperiodicity by which seasonal breeding vertebrates reciprocally switch thyroid hormone signaling according to prior photoperiodic history through epigenetic functions. From these perspectives, thyroid hormone signaling in a certain region was assumed to be activated in summer according to the prior shorter winter day length and inactivated in winter according to the prior longer summer day length. Regarding the prevalence of obesity, the coexistence of longer summer and winter day lengths was thought to set body composition to be short and fat in early adolescence.

Modern citrus nursery production makes use of potted-tree propagation in greenhouses. Supplemental lighting is one method by which nursery tree growth and profitability may be significantly improved, but limited specific information is available. Five replicated experiments were conducted to determine the utility and effects of increasing daylength during the winter months by supplemental illumination from lightemitting diode (LED) or high-pressure sodium (HPS) lights in citrus nursery propagation. Studies used 'Valencia' sweet orange scion, the most common citrus cultivar grown in Florida, and the commercially important rootstocks sour orange, 'Cleopatra' mandarin, 'US-812', 'US-897', 'US-942', and 'US-1516'. Comparisons used the three common types of citrus rootstock propagation: seed, stem cuttings, and micropropagation. Six responses were measured in the lighting experiments, including vegetative growth before budding, scion bud survival, and scion bud growth after budding. Supplemental HPS or LED light to extend daylength to 16 h in the citrus nursery during short-day winter months was observed to be effective in increasing unbudded rootstock liner growth and 'Valencia' scion growth on all rootstocks and propagation types. Generally, the positive effect on vegetative growth from an increased daylength was stronger with the HPS light than with LED light, while increasing daylength with LED light, but not HPS light, provided some increased bud growth initiation. Use of HPS or LED supplemental lighting to extend daylength offers significant growth advantage for the citrus nursery industry in winter. [ABSTRACT FROM AUTHOR]

Goat breeds from temperate and subtropical latitudes display reproductive seasonal variations. This reproductive seasonality causes a seasonality of milk, cheese, and meat production. To solve this problem, it is necessary to modify the annual season of parturitions. The photoperiod and the socio-sexual interactions can be used to manipulate the caprine reproduction. Therefore, in this review I will describe the photoperiodic treatments used to stimulate the sexual behavior of male goats during the sexual rest. Then, I will describe how these photos stimulated, sexually active bucks, are used to induce the sexual activity of females during the seasonal anestrous or to prevent the seasonal anovulation, allowing does to ovulate all the year round. These techniques constitute an original and sustainable manner to control caprine reproduction.

The renewable sources of energy are of utmost importance in context of the increasing energy demands. The sun energy available in abundance can be utilized effectively subjected to the availability of data on solar radiation flux, which remains the major concern. Solar radiation measurements are not economically feasible, requires maintenance and thus estimation of solar radiation flux data for utilization of solar irradiance plays vital role. For designing of any solar power systems, global solar radiation flux values are vital variables as solar energy generation depends on amount of solar radiation flux. Solar radiation flux is estimated to evaluate the workability of solar energy at Amravati, Maharashtra, India (20.9374 oN, 77.7796 oE). Solar radiation flux calculation is carried out for one year using MATLAB.

Purpose: It is known that delivery rates from spontaneous conception vary according to season which may be due to cultural or environmental factors; however, conflicting data exist regarding whether outcomes from IVF are also seasonally dependent. The present study was designed to test the hypothesis that the season at oocyte retrieval is associated with livebirth after fresh transfer. Methods: Dates of oocyte retrieval for all autologous cycles in our IVF program between January 2012 and December 2017 were categorized by season. Dates were linked to local temperature (min, max, average) and day length obtained from meteorological records. Average maximum temperature and day length were categorized into tertiles. Multivariable logistic regression, adjusted for age and quadratic age, were used to model odds (aOR) of implantation, clinical pregnancy, spontaneous abortion, and livebirth. Results: Patient characteristics were similar across seasons. As expected, temperature and day length varied by season. When compared with cycles started during winter, there was no difference in the age-adjusted odds of livebirth for the other three seasons (spring: aOR: 0.97, 95% CI: 0.82–1.13; summer: aOR: 1.05, 0.90–1.23; fall: aOR: 0.98, 0.84–1.15). There was a positive linear trend between temperature and odds of implantation, and clinical pregnancy (p value, test for linear trend (implantation, p = 0.02; clinical pregnancy, p = 0.01)) but no association with livebirth for temperature or day length. Conclusions: We found that season at oocyte retrieval was not associated with livebirth, contrary to patterns seen in naturally conceived populations. However, our data did suggest modestly higher odds of clinical pregnancy for retrievals in June and July, and that higher temperature at time of retrieval was associated with higher odds of clinical pregnancy but not livebirth. [ABSTRACT FROM AUTHOR]

Recent analyses have shown that typically diurnal primates may periodically exhibit some levels of activity at night. Despite this, there have been few studies that have explored whether diurnal primates living in temperate environments will extend their activity budgets to the nocturnal phase as a response to seasonal constraints. Using dual‐axis accelerometers, we explored whether chacma baboons (Papio ursinus; N = 3) in the western Soutpansberg Mountains, South Africa, responded to seasonally fluctuating levels of day length, lunar illumination, wind speed, precipitation and temperature by heightening or lowering nocturnal activity levels. Our results showed that chacma baboons engaged in low levels of activity at night throughout the year. Although baboons had heighted nocturnal activity as a response to shorter days, moonlit nights and lower temperatures, these responses were most likely due to disturbed sleeping patterns rather than more active movement. Nocturnal activity significantly dropped in a female baboon throughout the course of her pregnancy and remained low after giving birth suggesting that females with infants must increase resting. Our results compliment previous analyses which suggest that although diurnal primates may periodically be active at night, there is limited evidence for strategic use of the nocturnal phase even in highly seasonal environments. [ABSTRACT FROM AUTHOR]