Sample records for photoperiodic songbird express

  1. Temperature alters the photoperiodically controlled phenologies linked with migration and reproduction in a night-migratory songbird

    PubMed Central

    Singh, Jyoti; Budki, Puja; Rani, Sangeeta; Kumar, Vinod

    2012-01-01

    We investigated the effects of temperature on photoperiodic induction of the phenologies linked with migration (body fattening and premigratory night-time restlessness, Zugunruhe) and reproduction (testicular maturation) in the migratory blackheaded bunting. Birds were exposed for four weeks to near-threshold photoperiods required to induce testicular growth (11.5 L:12.5 D and 12 L:12 D) or for 18 weeks to a long photoperiod (13 L:11 D) at 22°C or 27°C (low) and 35°C or 40°C (high) temperatures. A significant body fattening and half-maximal testicular growth occurred in birds under the 12 L, but not under the 11.5 L photoperiod. Further, one of six birds in both temperature groups on 11.5 L, and four and two of six birds, respectively, in low- and high-temperature groups on 12 L showed the Zugunruhe. Buntings on 13 L in both temperature groups showed complete growth-regression cycles in body fattening, Zugunruhe and testis maturation. In birds on 13 L, high temperature attenuated activity levels, delayed onset of Zugunruhe by about 12 days, reduced body fattening and slowed testicular maturation. The effect of temperature seems to be on the rate of photoperiodic induction rather than on the critical day length. It is suggested that a change in temperature could alter the timing of the development of phenologies linked with seasonal migration and reproduction in migratory songbirds. PMID:21715403

  2. Adaptation of oxidative phosphorylation to photoperiod-induced seasonal metabolic states in migratory songbirds.

    PubMed

    Trivedi, Amit Kumar; Malik, Shalie; Rani, Sangeeta; Kumar, Vinod

    2015-06-01

    Eukaryotic cells produce chemical energy in the form of ATP by oxidative phosphorylation of metabolic fuels via a series of enzyme mediated biochemical reactions. We propose that the rates of these reactions are altered, as per energy needs of the seasonal metabolic states in avian migrants. To investigate this, blackheaded buntings were photoperiodically induced with non-migratory, premigratory, migratory and post-migratory phenotypes. High plasma levels of free fatty acids, citrate (an intermediate that begins the TCA cycle) and malate dehydrogenase (mdh, an enzyme involved at the end of the TCA cycle) confirmed increased availability of metabolic reserves and substrates to the TCA cycle during the premigratory and migratory states, respectively. Further, daily expression pattern of genes coding for enzymes involved in the oxidative decarboxylation of pyruvate to acetyl-CoA (pdc and pdk) and oxidative phosphorylation in the TCA cycle (cs, odgh, sdhd and mdh) was monitored in the hypothalamus and liver. Reciprocal relationship between pdc and pdk expressions conformed with the altered requirements of acetyl-CoA for the TCA cycle in different metabolic states. Except for pdk, all genes had a daily expression pattern, with high mRNA expression during the day in the premigratory/migratory phenotypes, and at night (cs, odhg, sdhd and mdh) in the nonmigratory phenotype. Differences in mRNA expression patterns of pdc, sdhd and mdh, but not of pdk, cs and odgh, between the hypothalamus and liver indicated a tissue dependent metabolism in buntings. These results suggest the adaptation of oxidative phosphorylation pathway(s) at gene levels to the seasonal alternations in metabolism in migratory songbirds. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Changes in photoperiod alter Glut4 expression in skeletal muscle of C57BL/6J mice

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tashiro, Ayako; Shibata, Satomi; Takai, Yusuke

    Seasonal changes in photoperiod influence body weight and metabolism in mice. Here, we examined the effect of changes in photoperiod on the expression of glucose transporter genes in the skeletal muscle and adipose tissue of C57BL/6J mice. Glut4 expression was lower in the gastrocnemius muscle of mice exposed to a short-duration day (SD) than those to a long-duration day (LD), with accompanying changes in GLUT4 protein levels. Although Glut4 expression in the mouse soleus muscle was higher under SD than under LD, GLUT4 protein levels remained unchanged. To confirm the functional significance of photoperiod-induced changes in Glut4 expression, we checkedmore » for variations in insulin sensitivity. Blood glucose levels after insulin injection remained high under SD, suggesting that the mice exposed to SD showed lower sensitivity to insulin than those exposed to LD. We also attempted to clarify the relationship between Glut4 expression and physical activity in the mice following changes in photoperiod. Locomotor activity, as detected via infrared beam sensor, was lower under SD than under LD. However, when we facilitated voluntary activity by using running wheels, the rotation of wheels was similar for both groups of mice. Although physical activity levels were enhanced due to running wheels, Glut4 expression in the gastrocnemius muscle remained unchanged. Thus, variations in photoperiod altered Glut4 expression in the mouse skeletal muscle, with subsequent changes in GLUT4 protein levels and insulin sensitivity; these effects might be independent of physical activity. - Highlights: • Glut4 expression in the gastrocnemius muscle was lowered under short photoperiod. • Insulin sensitivity was lowered under short photoperiod. • Access to running wheels did not alter Glut4 expression in the gastrocnemius muscle. • Photoperiodic changes in Glut4 expression may be independent of physical activity.« less

  4. Photoperiod regulates multiple gene expression in the suprachiasmatic nuclei and pars tuberalis of the Siberian hamster (Phodopus sungorus).

    PubMed

    Johnston, Jonathan D; Ebling, Francis J P; Hazlerigg, David G

    2005-06-01

    Photoperiod regulates the seasonal physiology of many mammals living in temperate latitudes. Photoperiodic information is decoded by the master circadian clock in the suprachiasmatic nuclei (SCN) of the hypothalamus and then transduced via pineal melatonin secretion. This neurochemical signal is interpreted by tissues expressing melatonin receptors (e.g. the pituitary pars tuberalis, PT) to drive physiological changes. In this study we analysed the photoperiodic regulation of the circadian clockwork in the SCN and PT of the Siberian hamster. Female hamsters were exposed to either long or short photoperiod for 8 weeks and sampled at 2-h intervals across the 24-h cycle. In the SCN, rhythmic expression of the clock genes Per1, Per2, Cry1, Rev-erbalpha, and the clock-controlled genes arginine vasopressin (AVP) and d-element binding protein (DBP) was modulated by photoperiod. All of these E-box-containing genes tracked dawn, with earlier peak mRNA expression in long, compared to short, photoperiod. This response occurred irrespective of the presence of additional regulatory cis-elements, suggesting photoperiodic regulation of SCN gene expression through a common E-box-related mechanism. In long photoperiod, expression of Cry1 and Per1 in the PT tracked the onset and offset of melatonin secretion, respectively. However, whereas Cry1 tracked melatonin onset in short period, Per1 expression was not detectably rhythmic. We therefore propose that, in the SCN, photoperiodic regulation of clock gene expression primarily occurs via E-boxes, whereas melatonin-driven signal transduction drives the phasing of a subset of clock genes in the PT, independently of the E-box.

  5. Existence of a photoinducible phase for ovarian development and photoperiod-related alteration of clock gene expression in a damselfish.

    PubMed

    Takeuchi, Yuki; Hada, Noriko; Imamura, Satoshi; Hur, Sung-Pyo; Bouchekioua, Selma; Takemura, Akihiro

    2015-10-01

    The sapphire devil, Chrysiptera cyanea, is a reef-associated damselfish and their ovarian development can be induced by a long photoperiod. In this study, we demonstrated the existence of a photoinducible phase for the photoperiodic ovarian development in the sapphire devil. Induction of ovarian development under night-interruption light schedules and Nanda-Hamner cycles revealed that the photoinducible phase appeared in a circadian manner between ZT12 and ZT13. To characterize the effect of photoperiod on clock gene expression in the brain of this species, we determined the expression levels of the sdPer1, sdPer2, sdCry1, and sdCry2 clock genes under constant light and dark conditions (LL and DD) and photoperiodic (short and long photoperiods). The expression of sdPer1 exhibited clear circadian oscillation under both LL and DD conditions, while sdPer2 and sdCry1 expression levels were lower under DD than under LL conditions and sdCry2 expression was lower under LL than under DD conditions. These results suggest a key role for sdPer1 in circadian clock cycling and that sdPer2, sdCry1, and sdCry2 are light-responsive clock genes in the sapphire devil. After 1 week under a long photoperiod, we observed photoperiod-related changes in sdPer1, sdPer2, and sdCry2 expression, but not in sdCry1 expression. These results suggest that the expression patterns of some clock genes exhibit seasonal variation according to seasonal changes in day length and that such seasonal alteration of clock gene expression may contribute to seasonal recognition by the sapphire devil. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Endocrine and social regulation of adult neurogenesis in songbirds.

    PubMed

    Balthazart, Jacques; Ball, Gregory F

    2016-04-01

    The identification of pronounced seasonal changes in the volume of avian song control nuclei stimulated the discovery of adult neurogenesis in songbirds as well as renewed studies in mammals including humans. Neurogenesis in songbirds is modulated by testosterone and other factors such as photoperiod, singing activity and social environment. Adult neurogenesis has been widely studied by labeling, with tritiated thymidine or its analog BrdU, cells duplicating their DNA in anticipation of their last mitotic division and following their fate as new neurons. New methods based on endogenous markers of cell cycling or of various stages of neuronal life have allowed for additional progress. In particular immunocytochemical visualization of the microtubule-associated protein doublecortin has provided an integrated view of neuronal replacement in the song control nucleus HVC. Multiple questions remain however concerning the specific steps in the neuronal life cycle that are modulated by various factors and the underlying cellular mechanisms. Copyright © 2016. Published by Elsevier Inc.

  7. Concurrent hypothalamic gene expression under acute and chronic long days: Implications for initiation and maintenance of photoperiodic response in migratory songbirds.

    PubMed

    Mishra, Ila; Bhardwaj, Sanjay K; Malik, Shalie; Kumar, Vinod

    2017-01-05

    Hypothalamic expression of the thyroid hormone (TH) responsive gonadostimulatory (eya3, cga, tshβ, dio2, dio3, gnrh, gnih) and neurosteroid pathway genes (androgen receptor [ar], aromatase [cyp19], estrogen receptor [er] α and β) was examined in photosensitive redheaded buntings exposed to 2 (acute, experiment 1) or 12 (chronic, experiment 2) long days (16L:8D). Experiment 2 also included a photorefractory group. Acute long days caused a significant increase in eya3, cga, tshβ, dio2 and gnrh and decrease in dio3 mRNA levels. eya3, cga and tshβ expressions were unchanged after the chronic long days. We also found increased cyp19, erα and erβ mRNA levels after acute, and increased cyp19 and decreased erβ levels after the chronic long-day exposure. Photorefractory buntings showed expression patterns similar to that in the photosensitive state, except for high gnrh and gnih and low dio3 mRNA levels. Consistent with gene expression patterns, there were changes in fat deposition, body mass, testis size, and plasma levels of testosterone, tri-iodothyronine and thyroxine. These results show concurrent photostimulation of the TH-signalling and neurosteroid pathways, and extend the idea, based on differences in gene expression, that transitions in seasonal photoperiodic states are accomplished at the transcriptional levels in absolute photorefractory species. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Rapid Induction of Hypothalamic Iodothyronine Deiodinase Expression by Photoperiod and Melatonin in Juvenile Siberian Hamsters (Phodopus sungorus)

    PubMed Central

    Prendergast, Brian J.; Pyter, Leah M.; Kampf-Lassin, August; Patel, Priyesh N.

    2013-01-01

    Production of T3 in the mediobasal hypothalamus is critical for regulation of seasonal reproductive physiology. Type 2 iodothyronine deiodinase (DIO2) and DIO3 enzymes catalyze the prohormone T4 into biologically-active T3 and biologically-inactive rT3, respectively. In several seasonally-breeding vertebrates, DIO2 and DIO3 expression is implicated in photoperiod signal transduction in adulthood. These experiments tested the hypothesis that juvenile Siberian hamsters, which are highly responsive to photoperiod at weaning (postnatal day [PND]18), exhibit rapid and sustained changes in hypothalamic dio3 mRNA expression during photoperiod-induced and photoperiod-inhibited puberty. Hypothalamic dio2 and dio3 expression was measured via quantitative PCR in hamsters born and reared in a long-day photoperiod (15L:9D) and weaned on PND18 into short-day photoperiods (9L:15D). In SD males, hypothalamic dio3 mRNA was elevated 2.5-fold within 3 days (PND21) and continued to increase (>20-fold) through PND32; changes in dio3 mRNA preceded inhibition of gonadotropin (FSH) secretion and gonadal regression in SD. Females exhibited comparable dio3 responses to SD. In LD males, dio3 remained low and invariant from PND18–PND32. In contrast, dio2 mRNA rose conspicuously on PND21, independent of photoperiod, returning to basal levels thereafter. In LD, a single afternoon melatonin (MEL) injection on PND18 or PND20 was sufficient to increase hypothalamic dio3 mRNA, and dio3 increased in proportion to the number of successive days of MEL treatment. SD photoperiods and MEL exert rapid, sustained, and additive effects on hypothalamic dio3 mRNA, which may play a central role in inhibiting maturation of the peripubertal hypothalamo-pituitary-gonadal axis. PMID:23295738

  9. Singing-driven gene expression in the developing songbird brain

    PubMed Central

    Johnson, Frank; Whitney, Osceola

    2014-01-01

    Neural and behavioral development arises from an integration of genetic and environmental influences, yet specifying the nature of this interaction remains a primary problem in neuroscience. Here, we review molecular and behavioral studies that focus on the role of singing-driven gene expression during neural and vocal development in the male zebra finch (Taeniopygia guttata), a songbird that learns a species-typical vocal pattern during juvenile development by imitating an adult male tutor. A primary aim of our lab has been to identify naturally-occurring environmental influences that shape the propensity to sing. This ethological approach underlies our theoretical perspective, which is to integrate the significance of singing-driven gene expression into a broader ecological context. PMID:16129463

  10. Genomic resources for songbird research and their use in characterizing gene expression during brain development

    PubMed Central

    Li, XiaoChing; Wang, Xiu-Jie; Tannenhauser, Jonathan; Podell, Sheila; Mukherjee, Piali; Hertel, Moritz; Biane, Jeremy; Masuda, Shoko; Nottebohm, Fernando; Gaasterland, Terry

    2007-01-01

    Vocal learning and neuronal replacement have been studied extensively in songbirds, but until recently, few molecular and genomic tools for songbird research existed. Here we describe new molecular/genomic resources developed in our laboratory. We made cDNA libraries from zebra finch (Taeniopygia guttata) brains at different developmental stages. A total of 11,000 cDNA clones from these libraries, representing 5,866 unique gene transcripts, were randomly picked and sequenced from the 3′ ends. A web-based database was established for clone tracking, sequence analysis, and functional annotations. Our cDNA libraries were not normalized. Sequencing ESTs without normalization produced many developmental stage-specific sequences, yielding insights into patterns of gene expression at different stages of brain development. In particular, the cDNA library made from brains at posthatching day 30–50, corresponding to the period of rapid song system development and song learning, has the most diverse and richest set of genes expressed. We also identified five microRNAs whose sequences are highly conserved between zebra finch and other species. We printed cDNA microarrays and profiled gene expression in the high vocal center of both adult male zebra finches and canaries (Serinus canaria). Genes differentially expressed in the high vocal center were identified from the microarray hybridization results. Selected genes were validated by in situ hybridization. Networks among the regulated genes were also identified. These resources provide songbird biologists with tools for genome annotation, comparative genomics, and microarray gene expression analysis. PMID:17426146

  11. Extra-hypothalamic brain clocks in songbirds: Photoperiodic state dependent clock gene oscillations in night-migratory blackheaded buntings, Emberiza melanocephala.

    PubMed

    Singh, Devraj; Kumar, Vinod

    2017-04-01

    The avian circadian pacemaker system is comprised of independent clocks in the retina, pineal and hypothalamus, as shown by daily and circadian oscillations of core clock genes (Per2, Cry1, Bmal1 and Clock) in several birds including migratory blackheaded buntings (Emberiza melanocephala). This study investigated the extra-hypothalamic brain circadian clocks in blackheaded buntings, and measured Per2, Cry1, Cry2, Bmal1 and Clock mRNA expressions at 4h intervals over 24h beginning 1h after light-on in the left and right telencephalon, optic tectum and cerebellum, the brain regions involved in several physiological and cognitive functions. Because of seasonal alterations in the circadian clock dependent brain functions, we measured daily clock gene oscillations in buntings photoperiod-induced with the non-migratory state under short days (SDnM), and the pre-migratory (LDpM), migratory (LDM) and post-migratory (refractory, LDR) states under long days. Daily Per2 oscillations were not altered with changes in the photoperiodic states, except for about 2-3h phase difference in the optic tectum between the SDnM and LDpM states. However, there were about 3-5h differences in the phase and 2 to 4 fold change in the amplitude of daily Bmal1 and Cry1 mRNA oscillations between the photoperiod-induced states. Further, Cry2 and Clock genes lacked a significant oscillation, except in Cb (Cry2) and TeO and Rt (Clock) under LDR state. Overall, these results show the presence of circadian clocks in extra-hypothalamic brain regions of blackheaded buntings, and suggest tissue-dependent alterations in the waveforms of mRNA oscillations with transitions in the photoperiod-induced seasonal states in a long-day species. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. The expression of the clock gene cycle has rhythmic pattern and is affected by photoperiod in the moth Sesamia nonagrioides.

    PubMed

    Kontogiannatos, Dimitrios; Gkouvitsas, Theodoros; Kourti, Anna

    2017-06-01

    To obtain clues to the link between the molecular mechanism of circadian and photoperiod clocks, we have cloned the circadian clock gene cycle (Sncyc) in the corn stalk borer, Sesamia nonagrioides, which undergoes facultative diapause controlled by photoperiod. Sequence analysis revealed a high degree of conservation among insects for this gene. SnCYC consists of 667 amino acids and structural analysis showed that it contains a BCTR domain in its C-terminal in addition to the common domains found in Drosophila CYC, i.e. bHLH, PAS-A, PAS-B domains. The results revealed that the sequence of Sncyc showed a similarity to that of its mammalian orthologue, Bmal1. We also investigated the expression patterns of Sncyc in the brain of larvae growing under long-day 16L: 8D (LD), constant darkness (DD) and short-day 10L: 14D (SD) conditions using qRT-PCR assays. The mRNAs of Sncyc expression was rhythmic in LD, DD and SD cycles. Also, it is remarkable that the photoperiodic conditions affect the expression patterns and/or amplitudes of circadian clock gene Sncyc. This gene is associated with diapause in S. nonagrioides, because under SD (diapause conditions) the photoperiodic signal altered mRNA accumulation. Sequence and expression analysis of cyc in S. nonagrioides shows interesting differences compared to Drosophila where this gene does not oscillate or change in expression patterns in response to photoperiod, suggesting that this species is an interesting new model to study the molecular control of insect circadian and photoperiodic clocks. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. DNA methylation pattern of Photoperiod-B1 is associated with photoperiod insensitivity in wheat (Triticum aestivum).

    PubMed

    Sun, Han; Guo, Zhiai; Gao, Lifeng; Zhao, Guangyao; Zhang, Wenping; Zhou, Ronghua; Wu, Yongzhen; Wang, Haiyang; An, Hailong; Jia, Jizeng

    2014-11-01

    As one of the three key components of the 'Green Revolution', photoperiod insensitivity is vital for improved adaptation of wheat (Triticum aestivum) cultivars to a wider geographical range. Photoperiod-B1a (Ppd-B1a) is one of the major genes that confers photoperiod insensitivity in 'Green Revolution' varieties, and has made a significant contribution to wheat yield improvement. In this study, we investigated the mechanisms underlying the photoperiod insensitivity of Ppd-B1a alleles from an epigenetic perspective using a combination of bisulfite genomic sequencing, orthologous comparative analysis, association analysis, linkage analysis and gene expression analysis. Based on the study of a large collection of wheat germplasm, we report two methylation haplotypes of Ppd-B1 and demonstrate that the higher methylation haplotype (haplotype a) was associated with increased copy numbers and higher expression levels of the Ppd-B1 gene, earlier heading and photoperiod insensitivity. Furthermore, assessment of the distribution frequency of the different methylation haplotypes suggested that the methylation patterns have undergone selection during the wheat breeding process. Our study suggests that DNA methylation in the regulatory region of the Ppd-B1 alleles, which is closely related to copy number variation, plays a significant role in wheat breeding, to confer photoperiod insensitivity and better adaptation to a wider geographical range. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  14. Auditory-vocal mirroring in songbirds.

    PubMed

    Mooney, Richard

    2014-01-01

    Mirror neurons are theorized to serve as a neural substrate for spoken language in humans, but the existence and functions of auditory-vocal mirror neurons in the human brain remain largely matters of speculation. Songbirds resemble humans in their capacity for vocal learning and depend on their learned songs to facilitate courtship and individual recognition. Recent neurophysiological studies have detected putative auditory-vocal mirror neurons in a sensorimotor region of the songbird's brain that plays an important role in expressive and receptive aspects of vocal communication. This review discusses the auditory and motor-related properties of these cells, considers their potential role on song learning and communication in relation to classical studies of birdsong, and points to the circuit and developmental mechanisms that may give rise to auditory-vocal mirroring in the songbird's brain.

  15. The expression patterns of the clock genes period and timeless are affected by photoperiod in the Mediterranean corn stalk borer, Sesamia nonagrioides.

    PubMed

    Kontogiannatos, Dimitrios; Gkouvitsas, Theodoros; Kourti, Anna

    2017-01-01

    To obtain clues to the link between the molecular mechanism of circadian and photoperiod clocks, we cloned two circadian clock genes, period (per) and timeless (tim) from the moth Sesamia nonagrioides, which undergoes facultative diapause controlled by photoperiod. Sequence analysis revealed a high degree of conservation among the compared insects fοr both genes. We also investigated the expression patterns of per and tim in brains of larvae growing under 16L:8D (long days), constant darkness (DD) and 10L:14D (short days) conditions by qPCR assays. The results showed that mRNA accumulations encoding both genes exhibited diel oscillations under different photoperiods. The oscillation of per and tim mRNA, under short-day photoperiod differed from long-day. The difference between long-day and short-day conditions in the pattern of mRNA levels of per and tim appears to distinguish photoperiodic conditions clearly and both genes were influenced by photoperiod in different ways. We infer that not all photoperiodic clocks of insects interact with circadian clocks in the same fashion. Our results suggest that transcriptional regulations of the both clock genes act in the diapause programing in S. nonagrioides. The expression patterns of these genes are affected by photoperiod but runs with 24 h by entrainment to daily environmental cues. © 2016 Wiley Periodicals, Inc.

  16. Auditory–vocal mirroring in songbirds

    PubMed Central

    Mooney, Richard

    2014-01-01

    Mirror neurons are theorized to serve as a neural substrate for spoken language in humans, but the existence and functions of auditory–vocal mirror neurons in the human brain remain largely matters of speculation. Songbirds resemble humans in their capacity for vocal learning and depend on their learned songs to facilitate courtship and individual recognition. Recent neurophysiological studies have detected putative auditory–vocal mirror neurons in a sensorimotor region of the songbird's brain that plays an important role in expressive and receptive aspects of vocal communication. This review discusses the auditory and motor-related properties of these cells, considers their potential role on song learning and communication in relation to classical studies of birdsong, and points to the circuit and developmental mechanisms that may give rise to auditory–vocal mirroring in the songbird's brain. PMID:24778375

  17. Seasonal neuronal plasticity in song-control and auditory forebrain areas in subtropical nonmigratory and palearctic-indian migratory male songbirds.

    PubMed

    Surbhi; Rastogi, Ashutosh; Malik, Shalie; Rani, Sangeeta; Kumar, Vinod

    2016-10-01

    This study examines whether differences in annual life-history states (LHSs) among the inhabitants of two latitudes would have an impact on the neuronal plasticity of the song-control system in songbirds. At the times of equinoxes and solstices during the year (n = 4 per year) corresponding to different LHSs, we measured the volumetric changes and expression of doublecortin (DCX; an endogenous marker of the neuronal recruitment) in the song-control nuclei and higher order auditory forebrain regions of the subtropical resident Indian weaverbirds (Ploceus philippinus) and Palearctic-Indian migratory redheaded buntings (Emberiza bruniceps). Area X in basal ganglia, lateral magnocellular nucleus of the anterior nidopallium (LMAN), HVC (proper name), and robust nucleus of the arcopallium (RA) were enlarged during the breeding LHS. Both round and fusiform DCX-immunoreactive (DCX-ir) cells were found in area X and HVC but not in LMAN or RA, with a significant seasonal difference. Also, as shown by increase in volume and by dense, round DCX-ir cells, the neuronal incorporation was increased in HVC alone during the breeding LHS. This suggests differences in the response of song-control nuclei to photoperiod-induced changes in LHSs. Furthermore, DCX immunoreactivity indicated participation of the cortical caudomedial nidopallium and caudomedial mesopallium in the song-control system, albeit with differences between the weaverbirds and the buntings. Overall, these results show seasonal neuronal plasticity in the song-control system closely associated with annual reproductive LHS in both of the songbirds. Differences between species probably account for the differences in the photoperiod-response system between the relative refractory weaverbirds and absolute refractory redheaded buntings. J. Comp. Neurol. 524:2914-2929, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Possible Involvement of Photoperiodic Regulation in Reproductive Endocrine System of Female Olive Flounder Paralichthys olivaceus.

    PubMed

    Kim, Hyun Chul; Lee, Chi Hoon; Hur, Sung Pyu; Kim, Byeong Hoon; Park, Jun Young; Lee, Young Don

    2015-03-01

    This study investigated possible involvement of photoperiodic regulation in reproductive endocrine system of female olive flounder. To investigate the influence on brain-pituitary axis in endocrine system by regulating photoperiod, compared expression level of Kisspeptin and sbGnRH mRNA in brain and FSH-β, LH-β and GH mRNA in pituitary before and after spawning. Photoperiod was treated natural photoperiod and long photoperiod (15L:9D) conditions from Aug. 2013 to Jun. 2014. Continuous long photoperiod treatment from Aug. (post-spawning phase) was inhibited gonadal development of female olive flounder. In natural photoperiod group, the Kiss2 expression level a significant declined in Mar. (spawning period). And also, FSH-β, LH-β and GH mRNA expression levels were increasing at this period. However, in long photoperiod group, hypothalamic Kiss2, FSH-β, LH-β and GH mRNA expression levels did not show any significant fluctuation. These results suggest that expression of hypothalamic Kiss2, GtH and GH in the pituitary would change in response to photoperiod and their possible involvement of photoperiodic regulation in reproductive endocrine system of the BPG axis.

  19. Photoperiod but not food restriction modulates innate immunity in an opportunistic breeder, Loxia curvirostra.

    PubMed

    Schultz, Elizabeth M; Hahn, Thomas P; Klasing, Kirk C

    2017-02-15

    An organism's investment in immune function often varies seasonally but understanding of how fluctuations in environmental conditions directly modulate investment remains limited. This experiment investigated how changes in photoperiod and food availability affect investment in constitutive innate immunity and the acute phase response induced by lipopolysaccharide (LPS) injections in captive red crossbills ( Loxia curvirostra ). Crossbills are reproductively flexible songbirds that specialize on an unpredictably available food resource and display temporal variation in immunity in the wild. Birds were separated into four treatments and exposed to long or short day lengths for 6 weeks before continuing on an ad libitum diet or experiencing a 20% food reduction for 10 days. Birds were un-injected or injected with LPS both before and after diet change. Innate immunity was quantified throughout the experiment to assess effects of photoperiod, food availability and their interactions on hemolysis-hemagglutination, haptoglobin, bacterial killing ability and leukocyte counts. Overall, increasing day length significantly increased both bacterial killing ability and leukocyte counts. Surprisingly, food restriction had little effect on the immune parameters, potentially owing to the 'low-cost' environment of captivity and suggesting that investment in innate immunity is prioritized and maintained whenever possible. LPS injections induced stereotypical sickness behaviors and increased bacterial killing ability in short day birds and complement activity (hemolysis) both before and after food restriction. These results demonstrate robust seasonal modulation of immune investment and an ability to maintain innate immunity in the face of limited resources in these temporally flexible songbirds. © 2017. Published by The Company of Biologists Ltd.

  20. Photoperiodic Modulation of Circadian Clock and Reproductive Axis Gene Expression in the Pre-Pubertal European Sea Bass Brain

    PubMed Central

    Martins, Rute S. T.; Gomez, Ana; Zanuy, Silvia; Carrillo, Manuel; Canário, Adelino V. M.

    2015-01-01

    The acquisition of reproductive competence requires the activation of the brain-pituitary-gonad (BPG) axis, which in most vertebrates, including fishes, is initiated by changes in photoperiod. In the European sea bass long-term exposure to continuous light (LL) alters the rhythm of reproductive hormones, delays spermatogenesis and reduces the incidence of precocious males. In contrast, an early shift from long to short photoperiod (AP) accelerates spermatogenesis. However, how photoperiod affects key genes in the brain to trigger the onset of puberty is still largely unknown. Here, we investigated if the integration of the light stimulus by clock proteins is sufficient to activate key genes that trigger the BPG axis in the European sea bass. We found that the clock genes clock, npas2, bmal1 and the BPG genes gnrh, kiss and kissr share conserved transcription factor frameworks in their promoters, suggesting co-regulation. Other gene promoters of the BGP axis were also predicted to be co-regulated by the same frameworks. Co-regulation was confirmed through gene expression analysis of brains from males exposed to LL or AP photoperiod compared to natural conditions: LL fish had suppressed gnrh1, kiss2, galr1b and esr1, while AP fish had stimulated npas2, gnrh1, gnrh2, kiss2, kiss1rb and galr1b compared to NP. It is concluded that fish exposed to different photoperiods present significant expression differences in some clock and reproductive axis related genes well before the first detectable endocrine and morphological responses of the BPG axis. PMID:26641263

  1. Effects of fasting, temperature, and photoperiod on preproghrelin mRNA expression in Chinese perch.

    PubMed

    Song, Yi; Zhao, Cheng; Liang, Xu-Fang; He, Shan; Tian, Changxu; Cheng, Xiaoyan; Yuan, Xiaochen; Lv, Liyuan; Guo, Wenjie; Xue, Min; Tao, Ya-Xiong

    2017-06-01

    Preproghrelin, a gut/brain peptide, plays an important role in the regulation of food intake and energy homeostasis in teleost and mammals. In the present study, we obtained the full-length preproghrelin cDNA in Chinese perch. The preproghrelin messenger RNA (mRNA) tissue expression showed that level was much higher in stomach and pituitary than in other tissues. The fasting study showed, after gastric emptying (3-6 h), short-term fasting (6-12 h) increased preproghrelin expression in the stomach. While in the pituitary, fasting reduced preproghrelin expression at 1, 3, 12, and 48 h, presenting state fluctuation of self-adjustment. The temperature study showed that the mRNA expression of preproghrelin was the highest in the brain at 26 °C and highest in the stomach at 32 °C, respectively, with different optimum temperature in these two tissues, reflecting spatiotemporal differences of regulation by central nervous system and peripheral organs. The photoperiod study showed that normal light (11 h of lightness and 13 h of darkness) led to highest preproghrelin expression, both in the brain and in the stomach, than continuous light or continuous dark, proving food intake is adapted to natural photoperiod or normal light in this study. These results all indicated that tissue-specific preproghrelin expression of Chinese perch could be significantly affected by environmental factors. Short-term fasting of 6 h after gastric emptying, 26 °C, and normal light led to higher preproghrelin expression, which indicated potential appetite increase in Chinese perch.

  2. Expression analysis of the speech-related genes FoxP1 and FoxP2 and their relation to singing behavior in two songbird species.

    PubMed

    Chen, Qianqian; Heston, Jonathan B; Burkett, Zachary D; White, Stephanie A

    2013-10-01

    Humans and songbirds are among the rare animal groups that exhibit socially learned vocalizations: speech and song, respectively. These vocal-learning capacities share a reliance on audition and cortico-basal ganglia circuitry, as well as neurogenetic mechanisms. Notably, the transcription factors Forkhead box proteins 1 and 2 (FoxP1, FoxP2) exhibit similar expression patterns in the cortex and basal ganglia of humans and the zebra finch species of songbird, among other brain regions. Mutations in either gene are associated with language disorders in humans. Experimental knock-down of FoxP2 in the basal ganglia song control region Area X during song development leads to imprecise copying of tutor songs. Moreover, FoxP2 levels decrease naturally within Area X when zebra finches sing. Here, we examined neural expression patterns of FoxP1 and FoxP2 mRNA in adult Bengalese finches, a songbird species whose songs exhibit greater sequence complexity and increased reliance on audition for maintaining their quality. We found that FoxP1 and FoxP2 expression in Bengalese finches is similar to that in zebra finches, including strong mRNA signals for both factors in multiple song control nuclei and enhancement of FoxP1 in these regions relative to surrounding brain tissue. As with zebra finches, when Bengalese finches sing, FoxP2 is behaviorally downregulated within basal ganglia Area X over a similar time course, and expression negatively correlates with the amount of singing. This study confirms that in multiple songbird species, FoxP1 expression highlights song control regions, and regulation of FoxP2 is associated with motor control of song.

  3. Expression analysis of the speech-related genes FoxP1 and FoxP2 and their relation to singing behavior in two songbird species

    PubMed Central

    Chen, Qianqian; Heston, Jonathan B.; Burkett, Zachary D.; White, Stephanie A.

    2013-01-01

    SUMMARY Humans and songbirds are among the rare animal groups that exhibit socially learned vocalizations: speech and song, respectively. These vocal-learning capacities share a reliance on audition and cortico-basal ganglia circuitry, as well as neurogenetic mechanisms. Notably, the transcription factors Forkhead box proteins 1 and 2 (FoxP1, FoxP2) exhibit similar expression patterns in the cortex and basal ganglia of humans and the zebra finch species of songbird, among other brain regions. Mutations in either gene are associated with language disorders in humans. Experimental knock-down of FoxP2 in the basal ganglia song control region Area X during song development leads to imprecise copying of tutor songs. Moreover, FoxP2 levels decrease naturally within Area X when zebra finches sing. Here, we examined neural expression patterns of FoxP1 and FoxP2 mRNA in adult Bengalese finches, a songbird species whose songs exhibit greater sequence complexity and increased reliance on audition for maintaining their quality. We found that FoxP1 and FoxP2 expression in Bengalese finches is similar to that in zebra finches, including strong mRNA signals for both factors in multiple song control nuclei and enhancement of FoxP1 in these regions relative to surrounding brain tissue. As with zebra finches, when Bengalese finches sing, FoxP2 is behaviorally downregulated within basal ganglia Area X over a similar time course, and expression negatively correlates with the amount of singing. This study confirms that in multiple songbird species, FoxP1 expression highlights song control regions, and regulation of FoxP2 is associated with motor control of song. PMID:24006346

  4. Evaluation of Reference Genes for Quantitative Real-Time PCR in Songbirds

    PubMed Central

    Zinzow-Kramer, Wendy M.; Horton, Brent M.; Maney, Donna L.

    2014-01-01

    Quantitative real-time PCR (qPCR) is becoming a popular tool for the quantification of gene expression in the brain and endocrine tissues of songbirds. Accurate analysis of qPCR data relies on the selection of appropriate reference genes for normalization, yet few papers on songbirds contain evidence of reference gene validation. Here, we evaluated the expression of ten potential reference genes (18S, ACTB, GAPDH, HMBS, HPRT, PPIA, RPL4, RPL32, TFRC, and UBC) in brain, pituitary, ovary, and testis in two species of songbird: zebra finch and white-throated sparrow. We used two algorithms, geNorm and NormFinder, to assess the stability of these reference genes in our samples. We found that the suitability of some of the most popular reference genes for target gene normalization in mammals, such as 18S, depended highly on tissue type. Thus, they are not the best choices for brain and gonad in these songbirds. In contrast, we identified alternative genes, such as HPRT, RPL4 and PPIA, that were highly stable in brain, pituitary, and gonad in these species. Our results suggest that the validation of reference genes in mammals does not necessarily extrapolate to other taxonomic groups. For researchers wishing to identify and evaluate suitable reference genes for qPCR songbirds, our results should serve as a starting point and should help increase the power and utility of songbird models in behavioral neuroendocrinology. PMID:24780145

  5. Determination of Photoperiod-Sensitive Phase in Chickpea (Cicer arietinum L.)

    PubMed Central

    Daba, Ketema; Warkentin, Thomas D.; Bueckert, Rosalind; Todd, Christopher D.; Tar’an, Bunyamin

    2016-01-01

    Photoperiod is one of the major environmental factors determining time to flower initiation and first flower appearance in plants. In chickpea, photoperiod sensitivity, expressed as delayed to flower under short days (SD) as compared to long days (LD), may change with the growth stage of the crop. Photoperiod-sensitive and -insensitive phases were identified by experiments in which individual plants were reciprocally transferred in a time series from LD to SD and vice versa in growth chambers. Eight chickpea accessions with differing degrees of photoperiod sensitivity were grown in two separate chambers, one of which was adjusted to LD (16 h light/8 h dark) and the other adjusted to SD (10 h light/14 h dark), with temperatures of 22/16°C (12 h light/12 h dark) in both chambers. The accessions included day-neutral (ICCV 96029 and FLIP 98-142C), intermediate (ICC 15294, ICC 8621, ILC 1687, and ICC 8855), and photoperiod-sensitive (CDC Corinne and CDC Frontier) responses. Control plants were grown continuously under the respective photoperiods. Reciprocal transfers of plants between the SD and LD photoperiod treatments were made at seven time points after sowing, customized for each accession based on previous data. Photoperiod sensitivity was detected in intermediate and photoperiod-sensitive accessions. For the day-neutral accession, ICCV 96029, there was no significant difference in the number of days to flowering of the plants grown under SD and LD as well as subsequent transfers. In photoperiod-sensitive accessions, three different phenological phases were identified: a photoperiod-insensitive pre-inductive phase, a photoperiod-sensitive inductive phase, and a photoperiod-insensitive post-inductive phase. The photoperiod-sensitive phase extends after flower initiation to full flower development. Results from this research will help to develop cultivars with shorter pre-inductive photoperiod-insensitive and photoperiod-sensitive phases to fit to regions with

  6. Fragaria vesca CONSTANS controls photoperiodic flowering and vegetative development.

    PubMed

    Kurokura, Takeshi; Samad, Samia; Koskela, Elli; Mouhu, Katriina; Hytönen, Timo

    2017-10-13

    According to the external coincidence model, photoperiodic flowering occurs when CONSTANS (CO) mRNA expression coincides with light in the afternoon of long days (LDs), leading to the activation of FLOWERING LOCUS T (FT). CO has evolved in Brassicaceae from other Group Ia CO-like (COL) proteins which do not control photoperiodic flowering in Arabidopsis. COLs in other species have evolved different functions as floral activators or even as repressors. To understand photoperiodic development in the perennial rosaceous model species woodland strawberry, we functionally characterized FvCO, the only Group Ia COL in its genome. We demonstrate that FvCO has a major role in the photoperiodic control of flowering and vegetative reproduction through runners. FvCO is needed to generate a bimodal rhythm of FvFT1 which encodes a floral activator in the LD accession Hawaii-4: a sharp FvCO expression peak at dawn is followed by the FvFT1 morning peak in LDs indicating possible direct regulation, but additional factors that may include FvGI and FvFKF1 are probably needed to schedule the second FvFT1 peak around dusk. These results demonstrate that although FvCO and FvFT1 play major roles in photoperiodic development, the CO-based external coincidence around dusk is not fully applicable to the woodland strawberry. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  7. An Evolutionarily Conserved DOF-CONSTANS Module Controls Plant Photoperiodic Signaling.

    PubMed

    Lucas-Reina, Eva; Romero-Campero, Francisco J; Romero, José M; Valverde, Federico

    2015-06-01

    The response to daylength is a crucial process that evolved very early in plant evolution, entitling the early green eukaryote to predict seasonal variability and attune its physiological responses to the environment. The photoperiod responses evolved into the complex signaling pathways that govern the angiosperm floral transition today. The Chlamydomonas reinhardtii DNA-Binding with One Finger (CrDOF) gene controls transcription in a photoperiod-dependent manner, and its misexpression influences algal growth and viability. In short days, CrDOF enhances CrCO expression, a homolog of plant CONSTANS (CO), by direct binding to its promoter, while it reduces the expression of cell division genes in long days independently of CrCO. In Arabidopsis (Arabidopsis thaliana), transgenic plants overexpressing CrDOF show floral delay and reduced expression of the photoperiodic genes CO and FLOWERING LOCUS T. The conservation of the DOF-CO module during plant evolution could be an important clue to understanding diversification by the inheritance of conserved gene toolkits in key developmental programs. © 2015 American Society of Plant Biologists. All Rights Reserved.

  8. Human mutant huntingtin disrupts vocal learning in transgenic songbirds.

    PubMed

    Liu, Wan-Chun; Kohn, Jessica; Szwed, Sarah K; Pariser, Eben; Sepe, Sharon; Haripal, Bhagwattie; Oshimori, Naoki; Marsala, Martin; Miyanohara, Atsushi; Lee, Ramee

    2015-11-01

    Speech and vocal impairments characterize many neurological disorders. However, the neurogenetic mechanisms of these disorders are not well understood, and current animal models do not have the necessary circuitry to recapitulate vocal learning deficits. We developed germline transgenic songbirds, zebra finches (Taneiopygia guttata) expressing human mutant huntingtin (mHTT), a protein responsible for the progressive deterioration of motor and cognitive function in Huntington's disease (HD). Although generally healthy, the mutant songbirds had severe vocal disorders, including poor vocal imitation, stuttering, and progressive syntax and syllable degradation. Their song abnormalities were associated with HD-related neuropathology and dysfunction of the cortical-basal ganglia (CBG) song circuit. These transgenics are, to the best of our knowledge, the first experimentally created, functional mutant songbirds. Their progressive and quantifiable vocal disorder, combined with circuit dysfunction in the CBG song system, offers a model for genetic manipulation and the development of therapeutic strategies for CBG-related vocal and motor disorders.

  9. Characterisation, analysis of expression and localisation of circadian clock genes from the perspective of photoperiodism in the aphid Acyrthosiphon pisum.

    PubMed

    Barberà, Miquel; Collantes-Alegre, Jorge Mariano; Martínez-Torres, David

    2017-04-01

    Aphids are typical photoperiodic insects that switch from viviparous parthenogenetic reproduction typical of long day seasons to oviparous sexual reproduction triggered by the shortening of photoperiod in autumn yielding an overwintering egg in which an embryonic diapause takes place. While the involvement of the circadian clock genes in photoperiodism in mammals is well established, there is still some controversy on their participation in insects. The availability of the genome of the pea aphid Acyrthosiphon pisum places this species as an excellent model to investigate the involvement of the circadian system in the aphid seasonal response. In the present report, we have advanced in the characterisation of the circadian clock genes and showed that these genes display extensive alternative splicing. Moreover, the expression of circadian clock genes, analysed at different moments of the day, showed a robust cycling of central clock genes period and timeless. Furthermore, the rhythmic expression of these genes was shown to be rapidly dampened under DD (continuous darkness conditions), thus supporting the model of a seasonal response based on a heavily dampened circadian oscillator. Additionally, increased expression of some of the circadian clock genes under short-day conditions suggest their involvement in the induction of the aphid seasonal response. Finally, in situ localisation of transcripts of genes period and timeless in the aphid brain revealed the site of clock neurons for the first time in aphids. Two groups of clock cells were identified: the Dorsal Neurons (DN) and the Lateral Neurons (LN), both in the protocerebrum. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Social information changes stress hormone receptor expression in the songbird brain.

    PubMed

    Cornelius, Jamie M; Perreau, Gillian; Bishop, Valerie R; Krause, Jesse S; Smith, Rachael; Hahn, Thomas P; Meddle, Simone L

    2018-01-01

    Social information is used by many vertebrate taxa to inform decision-making, including resource-mediated movements, yet the mechanisms whereby social information is integrated physiologically to affect such decisions remain unknown. Social information is known to influence the physiological response to food reduction in captive songbirds. Red crossbills (Loxia curvirostra) that were food reduced for several days showed significant elevations in circulating corticosterone (a "stress" hormone often responsive to food limitation) only if their neighbors were similarly food restricted. Physiological responses to glucocorticoid hormones are enacted through two receptors that may be expressed differentially in target tissues. Therefore, we investigated the influence of social information on the expression of the mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) mRNA in captive red crossbill brains. Although the role of MR and GR in the response to social information may be highly complex, we specifically predicted social information from food-restricted individuals would reduce MR and GR expression in two brain regions known to regulate hypothalamic-pituitary-adrenal (HPA) activity - given that reduced receptor expression may lessen the efficacy of negative feedback and release inhibitory tone on the HPA. Our results support these predictions - offering one potential mechanism whereby social cues could increase or sustain HPA-activity during stress. The data further suggest different mechanisms by which metabolic stress versus social information influence HPA activity and behavioral outcomes. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Gibberellins and stem growth in Arabidopsis thaliana. Effects of photoperiod on expression of the GA4 and GA5 loci.

    PubMed

    Xu, Y L; Gage, D A; Zeevaart, J A

    1997-08-01

    Arabidopsis thaliana (L.) Heynh. is a quantitative long-day (LD) rosette plant in which stem growth is mediated by gibberellins (CAs). Application of GAs to plants in short-day (SD) conditions resulted in rapid stem elongation and flower formation, with GA4 and GA9 being equally effective, and GA1 showing lower activity. The effects of photoperiod on the levels of endogenous GAs were measured by combined gas chromatography-mass spectrometry with selected ion monitoring. When plants were transferred from SD to LD conditions there was a slight decrease in the level of GA53 and an increase in the levels of C19-GAs, GA9, GA20, GA1, and GA8, indicating that GA 20-oxidase activity is stimulated in LD conditions. Expression of GA5, which encodes GA 20-oxidase, was highest in elongating stems and was correlated with the rate of stem elongation. By contrast, GA4, which encodes 3 beta-hydroxylase, showed low expression in stems and its expression was not correlated with the rate of stem elongation. We conclude that stem elongation in LD conditions is at least in part due to increased expression of GA5, whereas expression of GA4 is not under photoperiodic control.

  12. An Evolutionarily Conserved DOF-CONSTANS Module Controls Plant Photoperiodic Signaling1[OPEN

    PubMed Central

    2015-01-01

    The response to daylength is a crucial process that evolved very early in plant evolution, entitling the early green eukaryote to predict seasonal variability and attune its physiological responses to the environment. The photoperiod responses evolved into the complex signaling pathways that govern the angiosperm floral transition today. The Chlamydomonas reinhardtii DNA-Binding with One Finger (CrDOF) gene controls transcription in a photoperiod-dependent manner, and its misexpression influences algal growth and viability. In short days, CrDOF enhances CrCO expression, a homolog of plant CONSTANS (CO), by direct binding to its promoter, while it reduces the expression of cell division genes in long days independently of CrCO. In Arabidopsis (Arabidopsis thaliana), transgenic plants overexpressing CrDOF show floral delay and reduced expression of the photoperiodic genes CO and FLOWERING LOCUS T. The conservation of the DOF-CO module during plant evolution could be an important clue to understanding diversification by the inheritance of conserved gene toolkits in key developmental programs. PMID:25897001

  13. Season-dependent effects of photoperiod and temperature on circadian rhythm of arylalkylamine N-acetyltransferase2 gene expression in pineal organ of an air-breathing catfish, Clarias gariepinus.

    PubMed

    Singh, Kshetrimayum Manisana; Saha, Saurav; Gupta, Braj Bansh Prasad

    2017-08-01

    Arylalkylamine N-acetyltransferase (AANAT) activity, aanat gene expression and melatonin production have been reported to exhibit prominent circadian rhythm in the pineal organ of most species of fish. Three types of aanat genes are expressed in fish, but the fish pineal organ predominantly expresses aanat2 gene. Increase and decrease in daylength is invariably associated with increase and decrease in temperature, respectively. But so far no attempt has been made to delineate the role of photoperiod and temperature in regulation of the circadian rhythm of aanat2 gene expression in the pineal organ of any fish with special reference to seasons. Therefore, we studied effects of various lighting regimes (12L-12D, 16L-8D, 8L-16D, LL and DD) at a constant temperature (25°C) and effects of different temperatures (15°, 25° and 35°C) under a common photoperiod 12L-12D on circadian rhythm of aanat2 gene expression in the pineal organ of Clarias gariepinus during summer and winter seasons. Aanat2 gene expression in fish pineal organ was studied by measuring aanat2 mRNA levels using Real-Time PCR. Our findings indicate that the pineal organ of C. gariepinus exhibits a prominent circadian rhythm of aanat2 gene expression irrespective of photoperiods, temperatures and seasons, and the circadian rhythm of aanat2 gene expression responds differently to different photoperiods and temperatures in a season-dependent manner. Existence of circadian rhythm of aanat2 gene expression in pineal organs maintained in vitro under 12L-12D and DD conditions as well as a free running rhythm of the gene expression in pineal organ of the fish maintained under LL and DD conditions suggest that the fish pineal organ possesses an endogenous circadian oscillator, which is entrained by light-dark cycle. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. The impact of photoperiod insensitive Ppd-1a mutations on the photoperiod pathway across the three genomes of hexaploid wheat (Triticum aestivum).

    PubMed

    Shaw, Lindsay M; Turner, Adrian S; Laurie, David A

    2012-07-01

    Flowering time is a trait that has been extensively altered during wheat domestication, enabling it to be highly productive in diverse environments and providing a rich source of variation for studying adaptation mechanisms. Hexaploid wheat is ancestrally a long-day plant, but many environments require varieties with photoperiod insensitivity (PI) that can flower in short days. PI results from mutations in the Ppd-1 gene on the A, B or D genomes, with individual mutations conferring different degrees of earliness. The basis of this is poorly understood. Using a common genetic background, the effects of A, B and D genome PI mutations on genes of the circadian clock and photoperiod pathway were studied using genome-specific expression assays. Ppd-1 PI mutations did not affect the clock or immediate clock outputs, but affected TaCO1 and TaFT1, with a reduction in TaCO1 expression as TaFT1 expression increased. Therefore, although Ppd-1 is related to PRR genes of the Arabidopsis circadian clock, Ppd-1 affects flowering by an alternative route, most likely by upregulating TaFT1 with a feedback effect that reduces TaCO1 expression. Individual genes in the circadian clock and photoperiod pathway were predominantly expressed from one genome, and there was no genome specificity in Ppd-1 action. Lines combining PI mutations on two or three genomes had enhanced earliness with higher levels, but not earlier induction, of TaFT1, showing that there is a direct quantitative relationship between Ppd-1 mutations, TaFT1 expression and flowering. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

  15. FoxP2 in songbirds.

    PubMed

    Wohlgemuth, Sandra; Adam, Iris; Scharff, Constance

    2014-10-01

    Humans with mutations in the transcription factor FOXP2 display a severe speech disorder. Songbirds are a powerful model system to study FoxP2. Like humans, songbirds communicate via vocalizations that are imitatively learned during critical periods and this learning is influenced by social factors and relies on functionally lateralized neural circuits. During the past five years significant progress has been made moving from a descriptive to a more mechanistic understanding of how FoxP2 functions in songbirds. Current evidence from molecular and electrophysiological studies indicates that FoxP2 is important for shaping synaptic plasticity of specific neuron populations. One future goal will be to identify the transcriptional regulation orchestrated by FoxP2 and its associated molecular network that brings about these physiological effects. This will be key to further unravel how FoxP2 influences synaptic function and thereby contributes to auditory guided vocal motor behavior in the songbird model. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Kisspeptin mediates the photoperiodic control of reproduction in hamsters.

    PubMed

    Revel, Florent G; Saboureau, Michel; Masson-Pévet, Mireille; Pévet, Paul; Mikkelsen, Jens D; Simonneaux, Valérie

    2006-09-05

    The KiSS-1 gene encodes kisspeptin, the endogenous ligand of the G-protein-coupled receptor GPR54. Recent data indicate that the KiSS-1/GPR54 system is critical for the regulation of reproduction and is required for puberty onset. In seasonal breeders, reproduction is tightly controlled by photoperiod (i.e., day length). The Syrian hamster is a seasonal model in which reproductive activity is promoted by long summer days (LD) and inhibited by short winter days (SD). Using in situ hybridization and immunohistochemistry, we show that KiSS-1 is expressed in the arcuate nucleus of LD hamsters. Importantly, the KiSS-1 mRNA level was lower in SD animals but not in SD-refractory animals, which spontaneously reactivated their sexual activity after several months in SD. These changes of expression are not secondary to the photoperiodic variations of gonadal steroids. In contrast, melatonin appears to be necessary for these seasonal changes because pineal-gland ablation prevented the SD-induced downregulation of KiSS-1 expression. Remarkably, a chronic administration of kisspeptin-10 restored the testicular activity of SD hamsters despite persisting photoinhibitory conditions. Overall, these findings are consistent with a role of KiSS-1/GPR54 in the seasonal control of reproduction. We propose that photoperiod, via melatonin, modulates KiSS-1 signaling to drive the reproductive axis.

  17. Photorefractoriness in birds--photoperiodic and non-photoperiodic control.

    PubMed

    Dawson, Alistair; Sharp, Peter J

    2007-01-01

    Avian breeding seasons vary in length and in the degree of asymmetry with respect to the annual cycle in photoperiod to suit species-specific food resources. Asymmetry is the result of photorefractoriness. The degree of photorefractoriness, absolute or relative, is related to the length and asymmetry of the breeding season. Absolute photorefractoriness is associated with a marked decrease in hypothalamic cGnRH-I. However, during the initiation of absolute photorefractoriness there is a transient period during which the gonads regress in advance of the decrease in cGnRH-I, and this stage may be analogous to relative photorefractoriness. Photoinduced prolactin secretion has an inhibitory modulatory role during the initiation of absolute photorefractoriness, but is unlikely to be the only factor involved, while a possible role for avian gonadotrophin inhibitory hormone is not established. The first stage in the termination of photorefractoriness is the resumption of cGnRH-I synthesis. The major environmental cue driving gonadal maturation, and the transitions between the photosensitive state and photorefractoriness is the annual cycle in photoperiod. A range of non-photoperiodic cues may also play a role: social cues, climatic factors (temperature, rainfall, etc.), food availability and nutritional state. There is considerable evidence that these cues can influence gonadal maturation and the timing of egg-laying. There is some evidence that non-photoperiodic cues (certainly temperature and possibly social cues and food availability) can affect the timing of the onset of photorefractoriness, but no evidence that they can influence the time of the end of photorefractoriness.

  18. A Microarray-Based Analysis Reveals that a Short Photoperiod Promotes Hair Growth in the Arbas Cashmere Goat

    PubMed Central

    Guo, Jun; Wu, Dubala; Hao, Bayasihuliang; Li, Yurong; Zhao, Cunfa

    2016-01-01

    Many animals exhibit different behaviors in different seasons. The photoperiod can have effects on migration, breeding, fur growth, and other processes. The cyclic growth of the fur and feathers of some species of mammals and birds, respectively, is stimulated by the photoperiod as a result of hormone-dependent regulation of the nervous system. To further examine this phenomenon, we evaluated the Arbas Cashmere goat (Capra hircus), a species that is often used in this type of research. The goats were exposed to an experimentally controlled short photoperiod to study the regulation of cyclic cashmere growth. Exposure to a short photoperiod extended the anagen phase of the Cashmere goat hair follicle to increase cashmere production. Assessments of tissue sections indicated that the short photoperiod significantly induced cashmere growth. This conclusion was supported by a comparison of the differences in gene expression between the short photoperiod and natural conditions using gene chip technology. Using the gene chip data, we identified genes that showed altered expression under the short photoperiod compared to natural conditions, and these genes were found to be involved in the biological processes of hair follicle growth, structural composition of the hair follicle, and the morphogenesis of the surrounding skin appendages. Knowledge about differences in the expression of these genes as well as their functions and periodic regulation patterns increases our understanding of Cashmere goat hair follicle growth. This study also provides preliminary data that may be useful for the development of an artificial method to improve cashmere production by controlling the light cycle, which has practical significance for livestock breeding. PMID:26814503

  19. A Microarray-Based Analysis Reveals that a Short Photoperiod Promotes Hair Growth in the Arbas Cashmere Goat.

    PubMed

    Liu, Bin; Gao, Fengqin; Guo, Jun; Wu, Dubala; Hao, Bayasihuliang; Li, Yurong; Zhao, Cunfa

    2016-01-01

    Many animals exhibit different behaviors in different seasons. The photoperiod can have effects on migration, breeding, fur growth, and other processes. The cyclic growth of the fur and feathers of some species of mammals and birds, respectively, is stimulated by the photoperiod as a result of hormone-dependent regulation of the nervous system. To further examine this phenomenon, we evaluated the Arbas Cashmere goat (Capra hircus), a species that is often used in this type of research. The goats were exposed to an experimentally controlled short photoperiod to study the regulation of cyclic cashmere growth. Exposure to a short photoperiod extended the anagen phase of the Cashmere goat hair follicle to increase cashmere production. Assessments of tissue sections indicated that the short photoperiod significantly induced cashmere growth. This conclusion was supported by a comparison of the differences in gene expression between the short photoperiod and natural conditions using gene chip technology. Using the gene chip data, we identified genes that showed altered expression under the short photoperiod compared to natural conditions, and these genes were found to be involved in the biological processes of hair follicle growth, structural composition of the hair follicle, and the morphogenesis of the surrounding skin appendages. Knowledge about differences in the expression of these genes as well as their functions and periodic regulation patterns increases our understanding of Cashmere goat hair follicle growth. This study also provides preliminary data that may be useful for the development of an artificial method to improve cashmere production by controlling the light cycle, which has practical significance for livestock breeding.

  20. The opportunities and challenges of large-scale molecular approaches to songbird neurobiology

    PubMed Central

    Mello, C.V.; Clayton, D.F.

    2014-01-01

    High-through put methods for analyzing genome structure and function are having a large impact in song-bird neurobiology. Methods include genome sequencing and annotation, comparative genomics, DNA microarrays and transcriptomics, and the development of a brain atlas of gene expression. Key emerging findings include the identification of complex transcriptional programs active during singing, the robust brain expression of non-coding RNAs, evidence of profound variations in gene expression across brain regions, and the identification of molecular specializations within song production and learning circuits. Current challenges include the statistical analysis of large datasets, effective genome curations, the efficient localization of gene expression changes to specific neuronal circuits and cells, and the dissection of behavioral and environmental factors that influence brain gene expression. The field requires efficient methods for comparisons with organisms like chicken, which offer important anatomical, functional and behavioral contrasts. As sequencing costs plummet, opportunities emerge for comparative approaches that may help reveal evolutionary transitions contributing to vocal learning, social behavior and other properties that make songbirds such compelling research subjects. PMID:25280907

  1. Photoperiodic regulation of glycogen metabolism, glycolysis, and glutamine synthesis in tanycytes of the Siberian hamster suggests novel roles of tanycytes in hypothalamic function.

    PubMed

    Nilaweera, Kanishka; Herwig, Annika; Bolborea, Matei; Campbell, Gill; Mayer, Claus D; Morgan, Peter J; Ebling, Francis J P; Barrett, Perry

    2011-11-01

    The objective of this study is to investigate the impact of photoperiod on the temporal and spatial expression of genes involved in glucose metabolism in the brain of the seasonal mammal Phodopus sungorus (Siberian hamster). In situ hybridization was performed on brain sections obtained from male hamsters held in long photoperiod (high body weight and developed testes) or short photoperiod (reduced body weight with testicular regression). This analysis revealed upregulation in expression of genes involved in glycogen and glucose metabolism in short photoperiod and localized to the tanycyte layer of the third ventricle. On the basis of these data and a previously identified photoperiod-dependent increase in activity of neighboring hypothalamic neurons, we hypothesized that the observed expression changes may reflect alteration in either metabolic fuel or precursor neurotransmitter supply to surrounding neurons. Gene expression analysis was performed for genes involved in lactate and glutamate transport. This analysis showed that the gene for the lactate transporter MCT2 and glutamate transporter GLAST was decreased in the tanycyte layer in short photoperiod. Expression of mRNA for glutamine synthetase, the final enzyme in the synthesis of the neuronal neurotransmitter precursor, glutamine, was also decreased in short photoperiod. These data suggest a role for tanycytes in modulating glutamate concentrations and neurotransmitter supply in the hypothalamic environment. Copyright © 2011 Wiley-Liss, Inc.

  2. Circadian perinatal photoperiod has enduring effects on retinal dopamine and visual function.

    PubMed

    Jackson, Chad R; Capozzi, Megan; Dai, Heng; McMahon, Douglas G

    2014-03-26

    Visual system development depends on neural activity, driven by intrinsic and light-sensitive mechanisms. Here, we examined the effects on retinal function due to exposure to summer- and winter-like circadian light cycles during development and adulthood. Retinal light responses, visual behaviors, dopamine content, retinal morphology, and gene expression were assessed in mice reared in seasonal photoperiods consisting of light/dark cycles of 8:16, 16:8, and 12:12 h, respectively. Mice exposed to short, winter-like, light cycles showed enduring deficits in photopic retinal light responses and visual contrast sensitivity, but only transient changes were observed for scotopic measures. Dopamine levels were significantly lower in short photoperiod mice, and dopaminergic agonist treatment rescued the photopic light response deficits. Tyrosine hydroxylase and Early Growth Response factor-1 mRNA expression were reduced in short photoperiod retinas. Therefore, seasonal light cycles experienced during retinal development and maturation have lasting influence on retinal and visual function, likely through developmental programming of retinal dopamine.

  3. What songbirds teach us about learning

    NASA Astrophysics Data System (ADS)

    Brainard, Michael S.; Doupe, Allison J.

    2002-05-01

    Bird fanciers have known for centuries that songbirds learn their songs. This learning has striking parallels to speech acquisition: like humans, birds must hear the sounds of adults during a sensitive period, and must hear their own voice while learning to vocalize. With the discovery and investigation of discrete brain structures required for singing, songbirds are now providing insights into neural mechanisms of learning. Aided by a wealth of behavioural observations and species diversity, studies in songbirds are addressing such basic issues in neuroscience as perceptual and sensorimotor learning, developmental regulation of plasticity, and the control and function of adult neurogenesis.

  4. Distinct gene networks modulate floral induction of autonomous maize and photoperiod-dependent teosinte.

    PubMed

    Minow, Mark A A; Ávila, Luis M; Turner, Katie; Ponzoni, Elena; Mascheretti, Iride; Dussault, Forest M; Lukens, Lewis; Rossi, Vincenzo; Colasanti, Joseph

    2018-05-25

    Temperate maize was domesticated from its tropical ancestor, teosinte. Whereas temperate maize is an autonomous day-neutral plant, teosinte is an obligate short-day plant that requires uninterrupted long nights to induce flowering. Leaf-derived florigenic signals trigger reproductive growth in both teosinte and temperate maize. To study the genetic mechanisms underlying floral inductive pathways in maize and teosinte, mRNA and small RNA genome-wide expression analyses were conducted on leaf tissue from plants that were induced or not induced to flower. Transcriptome profiles reveal common differentially expressed genes during floral induction, but a comparison of candidate flowering time genes indicates that photoperiod and autonomous pathways act independently. Expression differences in teosinte are consistent with the current paradigm for photoperiod-induced flowering, where changes in circadian clock output trigger florigen production. Conversely, differentially expressed genes in temperate maize link carbon partitioning and flowering, but also show altered expression of circadian clock genes that are distinct from those altered upon photoperiodic induction in teosinte. Altered miRNA399 levels in both teosinte and maize suggest a novel common connection between flowering and phosphorus perception. These findings provide insights into the molecular mechanisms underlying a strengthened autonomous pathway that enabled maize growth throughout temperate regions.

  5. EARLY FLOWERING3 Redundancy Fine-Tunes Photoperiod Sensitivity1[OPEN

    PubMed Central

    Rubenach, Andrew J.S.; Vander Schoor, Jacqueline K.; Aubert, Gregoire; Burstin, Judith

    2017-01-01

    Three pea (Pisum sativum) loci controlling photoperiod sensitivity, HIGH RESPONSE (HR), DIE NEUTRALIS (DNE), and STERILE NODES (SN), have recently been shown to correspond to orthologs of Arabidopsis (Arabidopsis thaliana) circadian clock genes EARLY FLOWERING3 (ELF3), ELF4, and LUX ARRHYTHMO, respectively. A fourth pea locus, PHOTOPERIOD (PPD), also contributes to the photoperiod response in a similar manner to SN and DNE, and recessive ppd mutants on a spring-flowering hr mutant background show early, photoperiod-insensitive flowering. However, the molecular identity of PPD has so far remained elusive. Here, we show that the PPD locus also has a role in maintenance of diurnal and circadian gene expression rhythms and identify PPD as an ELF3 co-ortholog, termed ELF3b. Genetic interactions between pea ELF3 genes suggest that loss of PPD function does not affect flowering time in the presence of functional HR, whereas PPD can compensate only partially for the lack of HR. These results provide an illustration of how gene duplication and divergence can generate potential for the emergence of more subtle variations in phenotype that may be adaptively significant. PMID:28202598

  6. Language-related Cntnap2 gene is differentially expressed in sexually dimorphic song nuclei essential for vocal learning in songbirds

    PubMed Central

    Panaitof, S. Carmen; Abrahams, Brett S.; Dong, Hongmei; Geschwind, Daniel H.; White, Stephanie A.

    2010-01-01

    Multiple studies, involving distinct clinical populations, implicate contactin associated protein-like 2 (CNTNAP2) in aspects of language development and performance. While CNTNAP2 is broadly distributed in developing rodent brain, it shows a striking gradient of frontal cortical enrichment in developing human brain, consistent with a role in patterning circuits that subserve higher cognition and language. To test the hypothesis that CNTNAP2 may be important for learned vocal communication in additional species, we employed in situ hybridization to characterize transcript distribution in the zebra finch, an experimentally tractable songbird for which the neural substrate of this behavior is well-established. Consistent with an important role in learned vocalization, Cntnap2 was enriched or diminished in key song control nuclei relative to adjacent brain tissue. Importantly, this punctuated expression was observed in males, but not females, in accord with the sexual dimorphism of neural circuitry and vocal learning in this species. Ongoing functional work will provide important insights into the relationship between Cntnap2 and vocal communication in songbirds and thereby clarify mechanisms at play in disorders of human cognition and language. PMID:20394055

  7. PHOTOPERIODIC BEHAVIOR OF SUNFLOWER

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dyer, H.J.; Skok, J.; Scully, N.J.

    1959-09-01

    S>The sunflower, Helianthus annuus L., var. Mammoth Russian, has been shown to be a short-day type plant. It will, however, flower under a wide range of photoperiodic conditions, including excessively long days (as long as 20 hours) and a regime in which the daily dark periods are interrupted by 1-hour light periods if it be permitted to grow for a sufficiently long period. Short photoperiods promote flowering both by hastening the initiation of flower primordia and by hastening the development of primordia into macroscropic floral structures. Interruption of the dark periods by light is effective in inhibiting both the initiationmore » of flower primordia as well as the development of primordia into macroscopic floral structures. Sunflower thus exhibits a wide range of photoperiodic conditions under which flowering may take place plus an unusual variability in the time of flowering among individual plants in a given population. This may be related to the phenomenon pointed out by Habermann and Wallace: that a certain maturation requiremert or vegetative growth requirement for flowering must be met before flowering can occur. Stem elongation in sunflower is favored by long photoperiods. (auth)« less

  8. Genetic correlations and the evolution of photoperiodic time measurement within a local population of the pitcher-plant mosquito, Wyeomyia smithii

    PubMed Central

    Bradshaw, W E; Emerson, K J; Holzapfel, C M

    2012-01-01

    The genetic relationship between the daily circadian clock and the seasonal photoperiodic timer remains a subject of intense controversy. In Wyeomyia smithii, the critical photoperiod (an overt expression of the photoperiodic timer) evolves independently of the rhythmic response to the Nanda–Hamner protocol (an overt expression of the daily circadian clock) over a wide geographical range in North America. Herein, we focus on these two processes within a single local population in which there is a negative genetic correlation between them. We show that antagonistic selection against this genetic correlation rapidly breaks it down and, in fact, reverses its sign, showing that the genetic correlation is due primarily to linkage and not to pleiotropy. This rapid reversal of the genetic correlation within a small, single population means that it is difficult to argue that circadian rhythmicity forms the necessary, causal basis for the adaptive divergence of photoperiodic time measurement within populations or for the evolution of photoperiodic time measurement among populations over a broad geographical gradient of seasonal selection. PMID:22072069

  9. Effects of extended photoperiod on sandhill crane reproduction

    USGS Publications Warehouse

    Gee, G.F.; Pendleton, G.W.; Wood, Don A.

    1992-01-01

    Photoperiod studies were conducted with greater sandhill cranes (Grus canadensis tabida) from 1969 to 1972 and from 1982 to 1987 at the Patuxent Wildlife Research Center, Maryland. When housed indoors and exposed to long photoperiods, males produced semen during winter. When exposed to artificially extended photoperiods during spring in outdoor pens, females apparently laid earlier in the year and laid more eggs than they would have without the added light. Cranes did not exhibit any signs of photorefractory response to extended photoperiods.

  10. Tectonic collision and uplift of Wallacea triggered the global songbird radiation

    NASA Astrophysics Data System (ADS)

    Moyle, Robert G.; Oliveros, Carl H.; Andersen, Michael J.; Hosner, Peter A.; Benz, Brett W.; Manthey, Joseph D.; Travers, Scott L.; Brown, Rafe M.; Faircloth, Brant C.

    2016-08-01

    Songbirds (oscine passerines) are the most species-rich and cosmopolitan bird group, comprising almost half of global avian diversity. Songbirds originated in Australia, but the evolutionary trajectory from a single species in an isolated continent to worldwide proliferation is poorly understood. Here, we combine the first comprehensive genome-scale DNA sequence data set for songbirds, fossil-based time calibrations, and geologically informed biogeographic reconstructions to provide a well-supported evolutionary hypothesis for the group. We show that songbird diversification began in the Oligocene, but accelerated in the early Miocene, at approximately half the age of most previous estimates. This burst of diversification occurred coincident with extensive island formation in Wallacea, which provided the first dispersal corridor out of Australia, and resulted in independent waves of songbird expansion through Asia to the rest of the globe. Our results reconcile songbird evolution with Earth history and link a major radiation of terrestrial biodiversity to early diversification within an isolated Australian continent.

  11. Tectonic collision and uplift of Wallacea triggered the global songbird radiation.

    PubMed

    Moyle, Robert G; Oliveros, Carl H; Andersen, Michael J; Hosner, Peter A; Benz, Brett W; Manthey, Joseph D; Travers, Scott L; Brown, Rafe M; Faircloth, Brant C

    2016-08-30

    Songbirds (oscine passerines) are the most species-rich and cosmopolitan bird group, comprising almost half of global avian diversity. Songbirds originated in Australia, but the evolutionary trajectory from a single species in an isolated continent to worldwide proliferation is poorly understood. Here, we combine the first comprehensive genome-scale DNA sequence data set for songbirds, fossil-based time calibrations, and geologically informed biogeographic reconstructions to provide a well-supported evolutionary hypothesis for the group. We show that songbird diversification began in the Oligocene, but accelerated in the early Miocene, at approximately half the age of most previous estimates. This burst of diversification occurred coincident with extensive island formation in Wallacea, which provided the first dispersal corridor out of Australia, and resulted in independent waves of songbird expansion through Asia to the rest of the globe. Our results reconcile songbird evolution with Earth history and link a major radiation of terrestrial biodiversity to early diversification within an isolated Australian continent.

  12. Intraovarian expression of GnRH-1 and gonadotropin mRNA and protein levels in Siberian hamsters during the estrus cycle and photoperiod induced regression/recrudescence

    PubMed Central

    Shahed, Asha; Young, Kelly A.

    2010-01-01

    The hypothalamic-pituitary-gonadal (HPG) axis is the key reproductive regulator in vertebrates. While gonadotropin releasing hormone (GnRH), follicle stimulating (FSH), and luteinizing (LH) hormones are primarily produced in the hypothalamus and pituitary, they can be synthesized in the gonads, suggesting an intraovarian GnRH-gonadotropin axis. Because these hormones are critical for follicle maturation and steroidogenesis, we hypothesized that this intraovarian axis may be important in photoperiod-induced ovarian regression/recrudescence in seasonal breeders. Thus, we investigated GnRH-1 and gonadotropin mRNA and protein expression in Siberian hamster ovaries during (1) the estrous cycle; where ovaries from cycling long day hamsters (LD;16L:8D) were collected at proestrus, estrus, diestrus I, and diestrus II and (2) during photoperiod induced regression/ recrudescence; where ovaries were collected from hamsters exposed to 14wks of LD, short days (SD;8L:16D), or 8wks post-transfer to LD after 14wks SD (PT). GnRH-1, LHβ, FSHβ, and common α subunit mRNA expression was observed in cycling ovaries. GnRH-1 expression peaked at diestrus I compared to other stages (p<0.05). FSHβ and LHβ mRNA levels peaked at proestrus and diestrus I (p<0.05), with no change in the α subunit across the cycle (p>0.05). SD exposure decreased ovarian mass and plasma estradiol concentrations (p<0.05) and increased GnRH-1, LHβ, FSHβ, and α subunit mRNA expression as compared to LD and, except for LH, compared to PT (p<0.05). GnRH and gonadotropin protein was also dynamically expressed across the estrous cycle and photoperiod exposure. The presence of cycling intraovarian GnRH-1 and gonadotropin mRNA suggests that these hormones may be locally involved in ovarian maintenance during SD regression and/or could potentially serve to prime ovaries for rapid recrudescence. PMID:20955709

  13. Shared neural substrates for song discrimination in parental and parasitic songbirds.

    PubMed

    Louder, Matthew I M; Voss, Henning U; Manna, Thomas J; Carryl, Sophia S; London, Sarah E; Balakrishnan, Christopher N; Hauber, Mark E

    2016-05-27

    In many social animals, early exposure to conspecific stimuli is critical for the development of accurate species recognition. Obligate brood parasitic songbirds, however, forego parental care and young are raised by heterospecific hosts in the absence of conspecific stimuli. Having evolved from non-parasitic, parental ancestors, how brood parasites recognize their own species remains unclear. In parental songbirds (e.g. zebra finch Taeniopygia guttata), the primary and secondary auditory forebrain areas are known to be critical in the differential processing of conspecific vs. heterospecific songs. Here we demonstrate that the same auditory brain regions underlie song discrimination in adult brood parasitic pin-tailed whydahs (Vidua macroura), a close relative of the zebra finch lineage. Similar to zebra finches, whydahs showed stronger behavioral responses during conspecific vs. heterospecific song and tone pips as well as increased neural responses within the auditory forebrain, as measured by both functional magnetic resonance imaging (fMRI) and immediate early gene (IEG) expression. Given parallel behavioral and neuroanatomical patterns of song discrimination, our results suggest that the evolutionary transition to brood parasitism from parental songbirds likely involved an "evolutionary tinkering" of existing proximate mechanisms, rather than the wholesale reworking of the neural substrates of species recognition. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Skin transcriptome reveals the intrinsic molecular mechanisms underlying hair follicle cycling in Cashmere goats under natural and shortened photoperiod conditions.

    PubMed

    Yang, Min; Song, Shen; Dong, Kunzhe; Chen, XiaoFei; Liu, Xuexue; Rouzi, Marhaba; Zhao, Qianjun; He, Xiaohong; Pu, Yabin; Guan, Weijun; Ma, Yuehui; Jiang, Lin

    2017-10-18

    The growth of cashmere exhibits a seasonal pattern arising from photoperiod change. However, the underlying molecular mechanism remains unclear. We profiled the skin transcriptome of six goats at seven time points during hair follicle cycling via RNA-seq. The six goats comprised three goats exposed to a natural photoperiod and three exposed to a shortened photoperiod. During hair cycle transition, 1713 genes showed differential expression, and 332 genes showed a pattern of periodic expression. Moreover, a short photoperiod induced the hair follicle to enter anagen early, and 246 genes overlapped with the periodic genes. Among these key genes, cold-shock domain containing C2 (CSDC2) was highly expressed in the epidermis and dermis of Cashmere goat skin, although its function in hair-follicle development remains unknown. CSDC2 silencing in mouse fibroblasts resulted in the decreased mRNA expression of two key hair-follicle factors, leading to reduced cell numbers and a lower cell density. Cashmere growth or molting might be controlled by a set of periodic regulatory genes. The appropriate management of short light exposure can induce hair follicles to enter full anagen early through the activation of these regulators. The CSDC2 gene is a potentially important transcription factor in the hair growth cycle.

  15. Early experience shapes vocal neural coding and perception in songbirds

    PubMed Central

    Woolley, Sarah M. N.

    2012-01-01

    Songbirds, like humans, are highly accomplished vocal learners. The many parallels between speech and birdsong and conserved features of mammalian and avian auditory systems have led to the emergence of the songbird as a model system for studying the perceptual mechanisms of vocal communication. Laboratory research on songbirds allows the careful control of early life experience and high-resolution analysis of brain function during vocal learning, production and perception. Here, I review what songbird studies have revealed about the role of early experience in the development of vocal behavior, auditory perception and the processing of learned vocalizations by auditory neurons. The findings of these studies suggest general principles for how exposure to vocalizations during development and into adulthood influences the perception of learned vocal signals. PMID:22711657

  16. The effect of day-neutral mutations in barley and wheat on the interaction between photoperiod and vernalization.

    PubMed

    Turner, Adrian S; Faure, Sébastien; Zhang, Yang; Laurie, David A

    2013-09-01

    Vernalization-2 (Vrn-2) is the major flowering repressor in temperate cereals. It is only expressed under long days in wild-type plants. We used two day-neutral (photoperiod insensitive) mutations that allow rapid flowering in short or long days to investigate the day length control of Vrn-2. The barley (Hordeum vulgare) early maturity8 (eam8) mutation affects the barley ELF3 gene. eam8 mutants disrupt the circadian clock resulting in elevated expression of Ppd-H1 and the floral activator HvFT1 under short or long days. When eam8 was crossed into a genetic background with a vernalization requirement Vrn-2 was expressed under all photoperiods and the early flowering phenotype was partially repressed in unvernalized (UV) plants, likely due to competition between the constitutively active photoperiod pathway and the repressing effect of Vrn-2. We also investigated the wheat (Triticum aestivum) Ppd-D1a mutation. This differs from eam8 in causing elevated levels of Ppd-1 and TaFT1 expression without affecting the circadian clock. We used genotypes that differed in "short-day vernalization". Short days were effective in promoting flowering in individuals wild type at Ppd-D1, but not in individuals that carry the Ppd-D1a mutation. The latter showed Vrn-2 expression in short days. In summary, eam8 and Ppd-D1a mimic long days in terms of photoperiod response, causing Vrn-2 to become aberrantly expressed (in short days). As Ppd-D1a does not affect the circadian clock, this also shows that clock regulation of Vrn-2 operates indirectly through one or more downstream genes, one of which may be Ppd-1.

  17. PCH1 integrates circadian and light-signaling pathways to control photoperiod-responsive growth in Arabidopsis

    PubMed Central

    Huang, He; Yoo, Chan Yul; Bindbeutel, Rebecca; Goldsworthy, Jessica; Tielking, Allison; Alvarez, Sophie; Naldrett, Michael J; Evans, Bradley S; Chen, Meng; Nusinow, Dmitri A

    2016-01-01

    Plants react to seasonal change in day length through altering physiology and development. Factors that function to harmonize growth with photoperiod are poorly understood. Here we characterize a new protein that associates with both circadian clock and photoreceptor components, named PHOTOPERIODIC CONTROL OF HYPOCOTYL1 (PCH1). pch1 seedlings have overly elongated hypocotyls specifically under short days while constitutive expression of PCH1 shortens hypocotyls independent of day length. PCH1 peaks at dusk, binds phytochrome B (phyB) in a red light-dependent manner, and co-localizes with phyB into photobodies. PCH1 is necessary and sufficient to promote the biogenesis of large photobodies to maintain an active phyB pool after light exposure, potentiating red-light signaling and prolonging memory of prior illumination. Manipulating PCH1 alters PHYTOCHROME INTERACTING FACTOR 4 levels and regulates light-responsive gene expression. Thus, PCH1 is a new factor that regulates photoperiod-responsive growth by integrating the clock with light perception pathways through modulating daily phyB-signaling. DOI: http://dx.doi.org/10.7554/eLife.13292.001 PMID:26839287

  18. Genetic variation for farrowing rate in pigs in response to change in photoperiod and ambient temperature.

    PubMed

    Sevillano, C A; Mulder, H A; Rashidi, H; Mathur, P K; Knol, E F

    2016-08-01

    Seasonal infertility is often observed as anestrus and a lower conception rate resulting in a reduced farrowing rate (FR) during late summer and early autumn. This is often regarded as an effect of heat stress; however, we observed a reduction in the FR of sows even after correcting for ambient temperature in our data. Therefore, we added change in photoperiod in the analysis of FR considering its effect on sow fertility. Change in photoperiod was modeled using the cosine of the day of first insemination within a year. On an average, the FR decreased by 2% during early autumn with decreasing daily photoperiod compared with early summer with almost no change in daily photoperiod. It declined 0.2% per degree Celsius of ambient temperature above 19.2°C. This result is a step forward in disentangling the 2 environmental components responsible for seasonal infertility. Our next aim was to estimate the magnitude of genetic variation in FR in response to change in photoperiod and ambient temperature to explore opportunities for selecting pigs to have a constant FR throughout the year. We used reaction norm models to estimate additive genetic variation in response to change in photoperiod and ambient temperature. The results revealed a larger genetic variation at stressful environments when daily photoperiod decreased and ambient temperatures increased above 19.2°C compared with neutral environments. Genetic correlations between stressful environments and nonstressful environments ranged from 0.90 (±0.03) to 0.46 (±0.13) depending on the severity of the stress, indicating changes in expression of FR depending on the environment. The genetic correlation between responses of pigs to changes in photoperiod and to those in ambient temperature were positive, indicating that pigs tolerant to decreasing daily photoperiod are also tolerant to high ambient temperatures. Therefore, selection for tolerance to decreasing daily photoperiod should also increase tolerance to high

  19. Effects of "short" photoperiods on seedling growth of Pinus brutia.

    PubMed

    Iakovoglou, V; Radoglou, K; Kostopoulou, P; Dini-Papanastasi, O

    2012-03-01

    This study investigated how nurseries could benefit by inducing "short" photoperiods as low as 4 hr to produce "better" seedlings characterized by more vigorous roots; a substantial feature to overcome transplanting stress. The carryover effect of the photoperiod was also investigated on seedlings that grew for 30 days more underthe consistent 14 hr photoperiod. Seedlings of Pinus brutia were subjected to 4, 6, 8 and 14 hr photoperiod for 3 week. Fifteen seedlings were used to evaluate the leaf area, the root and shoot dry weight and their ratio. Six and sixteen seedlings were used to evaluate the shoot electrolyte leakage and the root growth potential, respectively. Based on the results, the 6 and 8 hr photoperiod indicated greater root allocation (4.8 and 4.9 mg, respectively) and chlorophyll content (3.7 and 4.4, respectively). They also indicated greater leaf area values (3.3 and 3.5 cm2, respectively) along with the 14 hr (3.4 cm2). The photoperiod effect continued even after seedlings were subjected at consistent photoperiod. Overall, "short" photoperiods could provide "better" P. brutia seedlings to accommodate immediate massive reforestation and afforestation needs.

  20. Photoperiod history differentially impacts reproduction and immune function in adult Siberian hamsters.

    PubMed

    Prendergast, Brian J; Pyter, Leah M

    2009-12-01

    Seasonal changes in numerous aspects of mammalian immune function arise as a result of the annual variation in environmental day length (photoperiod), but it is not known if absolute photoperiod or relative change in photoperiod drives these changes. This experiment tested the hypothesis that an individual's history of exposure to day length determines immune responses to ambiguous, intermediate-duration day lengths. Immunological (blood leukocytes, delayed-type hypersensitivity reactions [DTH]), reproductive, and adrenocortical responses were assessed in adult Siberian hamsters (Phodopus sungorus) that had been raised initially in categorically long (15-h light/day; 15L) or short (9L) photoperiods and were subsequently transferred to 1 of 7 cardinal experimental photoperiods between 9L and 15L, inclusive. Initial photoperiod history interacted with contemporary experimental photoperiods to determine reproductive responses: 11L, 12L, and 13L caused gonadal regression in hamsters previously exposed to 15L, but elicited growth in hamsters previously in 9L. In hamsters with a 15L photoperiod history, photoperiods < or = 11L elicited sustained enhancement of DTH responses, whereas in hamsters with a 9L photoperiod history, DTH responses were largely unaffected by increases in day length. Enhancement and suppression of blood leukocyte concentrations occurred at 13L in hamsters with photoperiod histories of 15L and 9L, respectively; however, prior exposure to 9L imparted marked hysteresis effects, which suppressed baseline leukocyte concentrations. Cortisol concentrations were only enhanced in 15L hamsters transferred to 9L and, in common with DTH, were unaffected by photoperiod treatments in hamsters with a 9L photoperiod history. Photoperiod history acquired in adulthood impacts immune responses to photoperiod, but manifests in a markedly dissimilar fashion as compared to the reproductive system. Prior photoperiod exposure has an enduring impact on the ability of the

  1. A photoperiod-responsive protein compendium and conceptual proteome roadmap outline in maize grown in growth chambers with controlled conditions

    PubMed Central

    Li, You-Zhi; Fan, Xian-Wei; Chen, Qiang; Zhong, Hao

    2017-01-01

    Maize (Zea mays L.) is one of the major staple food crops of the world. However, high photoperiod sensitivity, especially for tropical germplasms, impedes attempts to improve maize agronomical traits by integration of tropical and temperate maize germplasms. Physiological and phenotypic responses of maize to photoperiod have widely been investigated based on multi-site field observations; however, proteome-based responsive mechanisms under controlled photoperiod regimes, nutrient and moisture soils are not yet well understood. In the present study, we sequenced and analyzed six proteomes of tropically-adapted and photoperiod-sensitive M9 inbred line at the vegetative 3 stage and proteomes from tropically-adapted and photoperiod-sensitive Shuang M9 (SM9) inbred line at the vegetative-tasseling stage. All plants were grown in growth chambers with controlled soil and temperature and three photoperiod regimes, a short photoperiod (SP) of 10 h light/14 h dark, a control neutral photoperiod (NP) of 12 h light/12 h dark, and a long photoperiod (LP) of 16 h light/8 h dark for a daily cycle. We identified 4,395 proteins of which 401 and 425 differentially-expressed proteins (DPs) were found in abundance in M9 leaves and in SM9 leaves as per SP/LP vs. NP, respectively. Some DPs showed responses to both SP and LP while some only responded to either SP or LP, depending on M9 or SM9. Our study showed that the photoperiodic response pathway, circadian clock rhythm, and high light density/intensity crosstalk with each other, but apparently differ from dark signaling routes. Photoperiod response involves light-responsive or dark-responsive proteins or both. The DPs positioned on the signaling routes from photoperiod changes to RNA/DNA responses involve the mago nashi homolog and glycine-rich RNA-binding proteins. Moreover, the cell-to-cell movement of ZCN14 through plasmodesmata is likely blocked under a 16-h-light LP. Here, we propose a photoperiodic model based on our findings

  2. A proposed model for the flowering signaling pathway of sugarcane under photoperiodic control.

    PubMed

    Coelho, C P; Costa Netto, A P; Colasanti, J; Chalfun-Júnior, A

    2013-04-25

    Molecular analysis of floral induction in Arabidopsis has identified several flowering time genes related to 4 response networks defined by the autonomous, gibberellin, photoperiod, and vernalization pathways. Although grass flowering processes include ancestral functions shared by both mono- and dicots, they have developed their own mechanisms to transmit floral induction signals. Despite its high production capacity and its important role in biofuel production, almost no information is available about the flowering process in sugarcane. We searched the Sugarcane Expressed Sequence Tags database to look for elements of the flowering signaling pathway under photoperiodic control. Sequences showing significant similarity to flowering time genes of other species were clustered, annotated, and analyzed for conserved domains. Multiple alignments comparing the sequences found in the sugarcane database and those from other species were performed and their phylogenetic relationship assessed using the MEGA 4.0 software. Electronic Northerns were run with Cluster and TreeView programs, allowing us to identify putative members of the photoperiod-controlled flowering pathway of sugarcane.

  3. Neurogenomic Mechanisms of Aggression in Songbirds

    PubMed Central

    Maney, Donna L.; Goodson, James L.

    2017-01-01

    Our understanding of the biological basis of aggression in all vertebrates, including humans, has been built largely upon discoveries first made in birds. A voluminous literature now indicates that hormonal mechanisms are shared between humans and a number of avian species. Research on genetics mechanisms in birds has lagged behind the more typical laboratory species because the necessary tools have been lacking until recently. Over the past 30 years, three major technical advances have propelled forward our understanding of the hormonal, neural, and genetic bases of aggression in birds: (1) the development of assays to measure plasma levels of hormones in free-living individuals, or “field endocrinology”; (2) the immunohistochemical labeling of immediate early gene products to map neural responses to social stimuli; and (3) the sequencing of the zebra finch genome, which makes available a tremendous set of genomic tools for studying gene sequences, expression, and chromosomal structure in species for which we already have large datasets on aggressive behavior. This combination of hormonal, neuroendocrine, and genetic tools has established songbirds as powerful models for understanding the neural basis and evolution of aggression in vertebrates. In this chapter, we discuss the contributions of field endocrinology toward a theoretical framework linking aggression with sex steroids, explore evidence that the neural substrates of aggression are conserved across vertebrate species, and describe a promising new songbird model for studying the molecular genetic mechanisms underlying aggression. PMID:22078478

  4. Photosynthate partitioning to starch in Arabidopsis thaliana is insensitive to light intensity but sensitive to photoperiod due to a restriction on growth in the light in short photoperiods.

    PubMed

    Mengin, Virginie; Pyl, Eva-Theresa; Alexandre Moraes, Thiago; Sulpice, Ronan; Krohn, Nicole; Encke, Beatrice; Stitt, Mark

    2017-11-01

    Photoperiod duration can be predicted from previous days, but irradiance fluctuates in an unpredictable manner. To investigate how allocation to starch responds to changes in these two environmental variables, Arabidopsis Col-0 was grown in a 6 h and a 12 h photoperiod at three different irradiances. The absolute rate of starch accumulation increased when photoperiod duration was shortened and when irradiance was increased. The proportion of photosynthate allocated to starch increased strongly when photoperiod duration was decreased but only slightly when irradiance was decreased. There was a small increase in the daytime level of sucrose and twofold increases in glucose, fructose and glucose 6-phosphate at a given irradiance in short photoperiods compared to long photoperiods. The rate of starch accumulation correlated strongly with sucrose and glucose levels in the light, irrespective of whether these sugars were responding to a change in photoperiod or irradiance. Whole plant carbon budget modelling revealed a selective restriction of growth in the light period in short photoperiods. It is proposed that photoperiod sensing, possibly related to the duration of the night, restricts growth in the light period in short photoperiods, increasing allocation to starch and providing more carbon reserves to support metabolism and growth in the long night. © 2017 John Wiley & Sons Ltd.

  5. Photoperiod affects daily torpor and tissue fatty acid composition in deer mice

    NASA Astrophysics Data System (ADS)

    Geiser, Fritz; McAllan, B. M.; Kenagy, G. J.; Hiebert, Sara M.

    2007-04-01

    Photoperiod and dietary lipids both influence thermal physiology and the pattern of torpor of heterothermic mammals. The aim of the present study was to test the hypothesis that photoperiod-induced physiological changes are linked to differences in tissue fatty acid composition of deer mice, Peromyscus maniculatus (˜18-g body mass). Deer mice were acclimated for >8 weeks to one of three photoperiods (LD, light/dark): LD 8:16 (short photoperiod), LD 12:12 (equinox photoperiod), and LD 16:8 (long photoperiod). Deer mice under short and equinox photoperiods showed a greater occurrence of torpor than those under long photoperiods (71, 70, and 14%, respectively). The duration of torpor bouts was longest in deer mice under short photoperiod (9.3 ± 2.6 h), intermediate under equinox photoperiod (5.1 ± 0.3 h), and shortest under long photoperiod (3.7 ± 0.6 h). Physiological differences in torpor use were associated with significant alterations of fatty acid composition in ˜50% of the major fatty acids from leg muscle total lipids, whereas white adipose tissue fatty acid composition showed fewer changes. Our results provide the first evidence that physiological changes due to photoperiod exposure do result in changes in lipid composition in the muscle tissue of deer mice and suggest that these may play a role in survival of low body temperature and metabolic rate during torpor, thus, enhancing favourable energy balance over the course of the winter.

  6. Learning-related brain hemispheric dominance in sleeping songbirds.

    PubMed

    Moorman, Sanne; Gobes, Sharon M H; van de Kamp, Ferdinand C; Zandbergen, Matthijs A; Bolhuis, Johan J

    2015-03-12

    There are striking behavioural and neural parallels between the acquisition of speech in humans and song learning in songbirds. In humans, language-related brain activation is mostly lateralised to the left hemisphere. During language acquisition in humans, brain hemispheric lateralisation develops as language proficiency increases. Sleep is important for the formation of long-term memory, in humans as well as in other animals, including songbirds. Here, we measured neuronal activation (as the expression pattern of the immediate early gene ZENK) during sleep in juvenile zebra finch males that were still learning their songs from a tutor. We found that during sleep, there was learning-dependent lateralisation of spontaneous neuronal activation in the caudomedial nidopallium (NCM), a secondary auditory brain region that is involved in tutor song memory, while there was right hemisphere dominance of neuronal activation in HVC (used as a proper name), a premotor nucleus that is involved in song production and sensorimotor learning. Specifically, in the NCM, birds that imitated their tutors well were left dominant, while poor imitators were right dominant, similar to language-proficiency related lateralisation in humans. Given the avian-human parallels, lateralised neural activation during sleep may also be important for speech and language acquisition in human infants.

  7. Learning-related brain hemispheric dominance in sleeping songbirds

    PubMed Central

    Moorman, Sanne; Gobes, Sharon M. H.; van de Kamp, Ferdinand C.; Zandbergen, Matthijs A.; Bolhuis, Johan J.

    2015-01-01

    There are striking behavioural and neural parallels between the acquisition of speech in humans and song learning in songbirds. In humans, language-related brain activation is mostly lateralised to the left hemisphere. During language acquisition in humans, brain hemispheric lateralisation develops as language proficiency increases. Sleep is important for the formation of long-term memory, in humans as well as in other animals, including songbirds. Here, we measured neuronal activation (as the expression pattern of the immediate early gene ZENK) during sleep in juvenile zebra finch males that were still learning their songs from a tutor. We found that during sleep, there was learning-dependent lateralisation of spontaneous neuronal activation in the caudomedial nidopallium (NCM), a secondary auditory brain region that is involved in tutor song memory, while there was right hemisphere dominance of neuronal activation in HVC (used as a proper name), a premotor nucleus that is involved in song production and sensorimotor learning. Specifically, in the NCM, birds that imitated their tutors well were left dominant, while poor imitators were right dominant, similar to language-proficiency related lateralisation in humans. Given the avian-human parallels, lateralised neural activation during sleep may also be important for speech and language acquisition in human infants. PMID:25761654

  8. Expression of B-class MADS-box genes in response to variations in photoperiod is associated with chasmogamous and cleistogamous flower development in Viola philippica.

    PubMed

    Li, Qiaoxia; Huo, Qingdi; Wang, Juan; Zhao, Jing; Sun, Kun; He, Chaoying

    2016-07-07

    Some plants develop a breeding system that produces both chasmogamous (CH) and cleistogamous (CL) flowers. However, the underlying molecular mechanism remains elusive. In the present study, we observed that Viola philippica develops CH flowers with short daylight, whereas an extended photoperiod induces the formation of intermediate CL and CL flowers. In response to long daylight, the respective number and size of petals and stamens was lower and smaller than those of normally developed CH flowers, and a minimum of 14-h light induced complete CL flowers that had no petals but developed two stamens of reduced fertility. The floral ABC model indicates that B-class MADS-box genes largely influence the development of the affected two-whorl floral organs; therefore, we focused on characterizing these genes in V. philippica to understand this particular developmental transition. Three such genes were isolated and respectively designated as VpTM6-1, VpTM6-2, and VpPI. These were differentially expressed during floral development (particularly in petals and stamens) and the highest level of expression was observed in CH flowers; significantly low levels were detected in intermediate CL flowers, and the lowest level in CL flowers. The observed variations in the levels of expression after floral induction and organogenesis apparently occurred in response to variations in photoperiod. Therefore, inhibition of the development of petals and stamens might be due to the downregulation of B-class MADS-box gene expression by long daylight, thereby inducing the generation of CL flowers. Our work contributes to the understanding of the adaptive evolutionary formation of dimorphic flowers in plants.

  9. Vocal learning beyond imitation: mechanisms of adaptive vocal development in songbirds and human infants

    PubMed Central

    Tchernichovski, Ofer; Marcus, Gary

    2014-01-01

    Studies of vocal learning in songbirds typically focus on the acquisition of sensory templates for song imitation and on the consequent process of matching song production to templates. However, functional vocal development also requires the capacity to adaptively diverge from sensory templates, and to flexibly assemble vocal units. Examples of adaptive divergence include the corrective imitation of abnormal songs, and the decreased tendency to copy overabundant syllables. Such frequency-dependent effects might mirror tradeoffs between the assimilation of group identity (culture) while establishing individual and flexibly expressive songs. Intriguingly, although the requirements for vocal plasticity vary across songbirds, and more so between birdsong and language, the capacity to flexibly assemble vocal sounds develops in a similar, stepwise manner across species. Therefore, universal features of vocal learning go well beyond the capacity to imitate. PMID:25005823

  10. Female song is widespread and ancestral in songbirds.

    PubMed

    Odom, Karan J; Hall, Michelle L; Riebel, Katharina; Omland, Kevin E; Langmore, Naomi E

    2014-03-04

    Bird song has historically been considered an almost exclusively male trait, an observation fundamental to the formulation of Darwin's theory of sexual selection. Like other male ornaments, song is used by male songbirds to attract females and compete with rivals. Thus, bird song has become a textbook example of the power of sexual selection to lead to extreme neurological and behavioural sex differences. Here we present an extensive survey and ancestral state reconstruction of female song across songbirds showing that female song is present in 71% of surveyed species including 32 families, and that females sang in the common ancestor of modern songbirds. Our results reverse classical assumptions about the evolution of song and sex differences in birds. The challenge now is to identify whether sexual selection alone or broader processes, such as social or natural selection, best explain the evolution of elaborate traits in both sexes.

  11. Feeding habits of songbirds in East Texas clearcuts during winter

    Treesearch

    Donald W. Worthington; R. Montague Jr. Whiting; James G. Dickson

    2004-01-01

    This east Texas study was undertaken to determine the importance of seeds of forbs, grasses, and woody shrubs to songbirds wintering in young pine plantations which had been established utilizing the clearcut regeneration system. The feeding habits and preferences of four species of songbirds, northern cardinals (Cardinalis cardinalis), song sparrows...

  12. Temperature and photoperiod responses of soybean embryos cultured in vitro

    NASA Technical Reports Server (NTRS)

    Raper, C. D. Jr; Patterson, R. P.; Raper CD, J. r. (Principal Investigator)

    1986-01-01

    Temperature and photoperiod each have direct effects on growth rate of excised embryos of soybean (Glycine max (L.) Merrill). To determine if the effects of photoperiod are altered by temperature, embryos of 'Ransom II' were cultured in vitro at 18, 24, and 30 degrees C under photoperiod durations of 12 and 18 h at an irradiance of 9 W m-2 (700 to 850 nm) and a photosynthetic photon flux density of 58 micromoles m-2 s-1 (400 to 700 nm). Accumulation rates of fresh and dry weight were greater under 18-h than 12-h photoperiods over the entire range of temperature. Water content of the culture embryos was not affected by photoperiod but was greater at 18 and 30 than 24 degrees C. The accumulation rate of dry weight increased from 18 to 26 but declined at 30 degrees C.

  13. TCP4-dependent induction of CONSTANS transcription requires GIGANTEA in photoperiodic flowering in Arabidopsis

    PubMed Central

    Shim, Jae Sung; Song, Yong Hun; Laboy Cintrón, Dianne; Koyama, Tomotsugu; Ohme-Takagi, Masaru; Pruneda-Paz, Jose L.; Kay, Steve A.; MacCoss, Michael J.

    2017-01-01

    Photoperiod is one of the most reliable environmental cues for plants to regulate flowering timing. In Arabidopsis thaliana, CONSTANS (CO) transcription factor plays a central role in regulating photoperiodic flowering. In contrast to posttranslational regulation of CO protein, still little was known about CO transcriptional regulation. Here we show that the CINCINNATA (CIN) clade of class II TEOSINTE BRANCHED 1/ CYCLOIDEA/ PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR (TCP) proteins act as CO activators. Our yeast one-hybrid analysis revealed that class II CIN-TCPs, including TCP4, bind to the CO promoter. TCP4 induces CO expression around dusk by directly associating with the CO promoter in vivo. In addition, TCP4 binds to another flowering regulator, GIGANTEA (GI), in the nucleus, and induces CO expression in a GI-dependent manner. The physical association of TCP4 with the CO promoter was reduced in the gi mutant, suggesting that GI may enhance the DNA-binding ability of TCP4. Our tandem affinity purification coupled with mass spectrometry (TAP-MS) analysis identified all class II CIN-TCPs as the components of the in vivo TCP4 complex, and the gi mutant did not alter the composition of the TCP4 complex. Taken together, our results demonstrate a novel function of CIN-TCPs as photoperiodic flowering regulators, which may contribute to coordinating plant development with flowering regulation. PMID:28628608

  14. TCP4-dependent induction of CONSTANS transcription requires GIGANTEA in photoperiodic flowering in Arabidopsis.

    PubMed

    Kubota, Akane; Ito, Shogo; Shim, Jae Sung; Johnson, Richard S; Song, Yong Hun; Breton, Ghislain; Goralogia, Greg S; Kwon, Michael S; Laboy Cintrón, Dianne; Koyama, Tomotsugu; Ohme-Takagi, Masaru; Pruneda-Paz, Jose L; Kay, Steve A; MacCoss, Michael J; Imaizumi, Takato

    2017-06-01

    Photoperiod is one of the most reliable environmental cues for plants to regulate flowering timing. In Arabidopsis thaliana, CONSTANS (CO) transcription factor plays a central role in regulating photoperiodic flowering. In contrast to posttranslational regulation of CO protein, still little was known about CO transcriptional regulation. Here we show that the CINCINNATA (CIN) clade of class II TEOSINTE BRANCHED 1/ CYCLOIDEA/ PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR (TCP) proteins act as CO activators. Our yeast one-hybrid analysis revealed that class II CIN-TCPs, including TCP4, bind to the CO promoter. TCP4 induces CO expression around dusk by directly associating with the CO promoter in vivo. In addition, TCP4 binds to another flowering regulator, GIGANTEA (GI), in the nucleus, and induces CO expression in a GI-dependent manner. The physical association of TCP4 with the CO promoter was reduced in the gi mutant, suggesting that GI may enhance the DNA-binding ability of TCP4. Our tandem affinity purification coupled with mass spectrometry (TAP-MS) analysis identified all class II CIN-TCPs as the components of the in vivo TCP4 complex, and the gi mutant did not alter the composition of the TCP4 complex. Taken together, our results demonstrate a novel function of CIN-TCPs as photoperiodic flowering regulators, which may contribute to coordinating plant development with flowering regulation.

  15. Relationships between forest songbird populations and managed forests in Idaho

    Treesearch

    Diane M. Evans; Deborah M. Finch

    1994-01-01

    Many species of songbirds have experienced population declines. In the eastern U.S. in recent years, but conclusive data on population trends and factors affecting populations in the West are lacking. Few studies have evaluated the importance of surrounding land configuration to songbird abundances. In 1992, we initiated a study in mixed conifer forest in west-central...

  16. Photoperiodic regulation of cellular retinol binding protein, CRBP1 [corrected] and nestin in tanycytes of the third ventricle ependymal layer of the Siberian hamster.

    PubMed

    Barrett, Perry; Ivanova, Elena; Graham, E Scott; Ross, Alexander W; Wilson, Dana; Plé, Helene; Mercer, Julian G; Ebling, Francis J; Schuhler, Sandrine; Dupré, Sandrine M; Loudon, Andrew; Morgan, Peter J

    2006-12-01

    Tanycytes in the ependymal layer of the third ventricle act both as a barrier and a communication gateway between the cerebrospinal fluid, brain and portal blood supply to the pituitary gland. However, the range, importance and mechanisms involved in the function of tanycytes remain to be explored. In this study, we have utilized a photoperiodic animal to examine the expression of three unrelated gene sequences in relation to photoperiod-induced changes in seasonal physiology and behaviour. We demonstrate that cellular retinol binding protein [corrected] (CRBP1), a retinoic acid transport protein, GPR50, an orphan G-protein-coupled receptor and nestin, an intermediate filament protein, are down-regulated in short-day photoperiods. The distribution of the three sequences is very similar, with expression located in cells with tanycyte morphology in the region of the ependymal layer where tanycytes are located. Furthermore, CRBP1 expression in the ependymal layer is shown to be independent of a circadian clock and altered testosterone levels associated with testicular regression in short photo-period. Pinealectomy of Siberian hamsters demonstrates CRBP1 expression is likely to be dependent on melatonin output from the pineal gland. This provides evidence that tanycytes are seasonally responsive cells and are likely to be an important part of the mechanism to facilitate seasonal physiology and behaviour in the Siberian hamster.

  17. Common, but Commonly Overlooked: Red-bellied Woodpeckers as Songbird Nest Predators

    Treesearch

    Kirsten R. Hazler; Dawn E.W. Drumtra; Matthew R. Marshall; Robert J. Cooper; Paul B. Hamel

    2004-01-01

    Woodpeckers in North America are not widely recognized as nest predators. In this paper, we describe several eyewitness accounts of songbird nest predation by Red-bellied Woodpeckers (Melanerpes carolinus), document evidence that songbirds recognize woodpeckers as nest predators, and show that our observations are consistent with previously published...

  18. Photoperiod- and Warming-driven Phenological Changes and Carbon and Nutrient Cycling. Remote Sensing Assessment

    NASA Astrophysics Data System (ADS)

    Penuelas, J.; Fu, Y.; Estiarte, M.; Gamon, J. A.; Filella, I.; Verger, A.; Jannssens, I.

    2017-12-01

    Ongoing spring warming allows the growing season to begin earlier in northern ecosystems, thus enhancing their carbon uptake. We will present data on atmospheric CO2 concentration measurements to show that this spring advancement of annual carbon intake in response to warming is decreasing. Reduced chilling during dormancy and the interactions between temperature and photoperiod in driving leaf-out may play a role. We will show that short photoperiod (in warm springs when leaf-out is early) significantly increases the heat requirement for leaf-out whereas long photoperiod (in cold springs when leaf-out is late) reduces the heat requirement for leaf-out. These two contrasting photoperiod effects illustrate a complicated temperature response of leaf-out phenology. We will also discuss how photoperiod exerts a strict control on leaf senescence at latitudes where winters are severe and temperature gains importance in the regulation as winters become less severe. On average, climatic warming will delay and drought will advance leaf senescence, but at varying degrees depending on the species. Warming and drought thus have opposite effects on the phenology of leaf senescence, and the impact of climate change will therefore depend on the relative importance of each factor in specific regions. We will then discuss the ecological effects of these phenological changes focusing, as an example, on the impacts of changes on the phenology of leaf senescence on carbon uptake and nutrient cycling. Finally, we will present recent advances on remote sensing monitoring of both the phenological changes and their ecological impacts. We will focus on advances derived from a close correspondence between seasonally changing foliar pigment levels, expressed as chlorophyll/carotenoid ratios, and evergreen photosynthetic activity.

  19. Effect of photoperiod on flowering of cypress vine (Ipomea quamoclit L.)

    NASA Astrophysics Data System (ADS)

    Koike, Yasuhiko

    2013-05-01

    Plants of Ipomoea quamoclit L. were exposed to an 8-hour photoperiod under natural daylight, which was supplemented with 60 W incandescent lamps to give an 8- to 24-hour day. Under photoperiods of 12 hours or less, flower buds were initiated, while the period from bud formation to flowering was shortened in plants grown under a 12-hour photoperiod. Photoperiods of 12 hours or less had no effect on plant height and number of nodes. The present results suggest that Ipomoea quamoclit L. is a short-day plant.

  20. Songbird status and roles

    Treesearch

    Linnea S. Hall; Michael L. Morrison; William M. Block

    1997-01-01

    This chapter reviews studies on songbird ecology conducted in Arizona, New Mexico, and Colorado; studies from outside this region are mentioned when they bear direct relevance to our primary region. The studies were conducted in sites where ponderosa pine occurred at least in equal coverage with other trees. We also include studies conducted in pine-oak (pine...

  1. The Pineal and Photoperiodism in Artic Species,

    DTIC Science & Technology

    1977-01-01

    University of Iowa, Iowa City, Iowa *1 A chapter in the book: The Pineal Gland and Reproduction / ::. . / .. ,, " /-. ., . / >( JUN19 1981 A and sale; . td...Three Kinds of Bird Pineal Glands Arctic Mammals and Photoperiod Outline of Arctic Reproductive Physiology Arctic Pineal Physiology: Size Arctic... pineal physiology. Because this gland is not only associated with photoperiodic responses with some species, but also with resistance to cold (14; 21

  2. A pseudo-response regulator is misexpressed in the photoperiod insensitive Ppd-D1a mutant of wheat (Triticum aestivum L.).

    PubMed

    Beales, James; Turner, Adrian; Griffiths, Simon; Snape, John W; Laurie, David A

    2007-09-01

    Ppd-D1 on chromosome 2D is the major photoperiod response locus in hexaploid wheat (Triticum aestivum). A semi-dominant mutation widely used in the "green revolution" converts wheat from a long day (LD) to a photoperiod insensitive (day neutral) plant, providing adaptation to a broad range of environments. Comparative mapping shows Ppd-D1 to be colinear with the Ppd-H1 gene of barley (Hordeum vulgare) which is a member of the pseudo-response regulator (PRR) gene family. To investigate the relationship between wheat and barley photoperiod genes we isolated homologues of Ppd-H1 from a 'Chinese Spring' wheat BAC library and compared them to sequences from other wheat varieties with known Ppd alleles. Varieties with the photoperiod insensitive Ppd-D1a allele which causes early flowering in short (SD) or LDs had a 2 kb deletion upstream of the coding region. This was associated with misexpression of the 2D PRR gene and expression of the key floral regulator FT in SDs, showing that photoperiod insensitivity is due to activation of a known photoperiod pathway irrespective of day length. Five Ppd-D1 alleles were found but only the 2 kb deletion was associated with photoperiod insensitivity. Photoperiod insensitivity can also be conferred by mutation at a homoeologous locus on chromosome 2B (Ppd-B1). No candidate mutation was found in the 2B PRR gene but polymorphism within the 2B PRR gene cosegregated with the Ppd-B1 locus in a doubled haploid population, suggesting that insensitivity on 2B is due to a mutation outside the sequenced region or to a closely linked gene.

  3. Photoperiodic controls on ecosystem-level photosynthetic capacity

    NASA Astrophysics Data System (ADS)

    Stoy, P. C.; Trowbridge, A. M.; Bauerle, W.

    2012-12-01

    Most models of photosynthesis at the leaf or canopy level assume that temperature is the dominant control on the variability of photosynthetic parameters. Recent studies, however, have found that photoperiod is a better descriptor of the seasonal variability of photosynthetic function at the leaf and plant scale, and that spectral indices of leaf functionality are poor descriptors of this seasonality. We explored the variability of photosynthesic parameters at the ecosystem scale using over 100 site-years of air temperature and gross primary productivity (GPP) data from non-tropical forested sites in the Free/Fair Use LaThuille FLUXNET database (www.fluxdata.org), excluding sites that were classified as dry and/or with savanna vegetation, where we expected GPP to be driven by moisture availability. Both GPP and GPP normalized by daily photosynthetic photon flux density (GPPn) were considered, and photoperiod was calculated from eddy covariance tower coordinates. We performed a Granger causality analysis, a method based on the understanding that causes precede effects, on both the GPP and GPPn. Photoperiod Granger-caused GPP (GPPn) in 95% (87%) of all site-years. While temperature Granger-caused GPP in a mere 23% of site years, it Granger-caused GPPn 73% of the time. Both temperature values are significantly less than the percent of cases in which day length Granger-caused GPP (p<0.05, Student's t-test). An inverse analysis was performed for completeness, and it was found that GPP Granger-caused photoperiod (temperature) in 39% (78%) of all site years. Results demonstrate that incorporating simple photoperiod controls may be a logical step in improving ecosystem and global model output.

  4. Emlen funnel experiments revisited: methods update for studying compass orientation in songbirds.

    PubMed

    Bianco, Giuseppe; Ilieva, Mihaela; Veibäck, Clas; Öfjäll, Kristoffer; Gadomska, Alicja; Hendeby, Gustaf; Felsberg, Michael; Gustafsson, Fredrik; Åkesson, Susanne

    2016-10-01

    Migratory songbirds carry an inherited capacity to migrate several thousand kilometers each year crossing continental landmasses and barriers between distant breeding sites and wintering areas. How individual songbirds manage with extreme precision to find their way is still largely unknown. The functional characteristics of biological compasses used by songbird migrants has mainly been investigated by recording the birds directed migratory activity in circular cages, so-called Emlen funnels. This method is 50 years old and has not received major updates over the past decades. The aim of this work was to compare the results from newly developed digital methods with the established manual methods to evaluate songbird migratory activity and orientation in circular cages.We performed orientation experiments using the European robin ( Erithacus rubecula ) using modified Emlen funnels equipped with thermal paper and simultaneously recorded the songbird movements from above. We evaluated and compared the results obtained with five different methods. Two methods have been commonly used in songbirds' orientation experiments; the other three methods were developed for this study and were based either on evaluation of the thermal paper using automated image analysis, or on the analysis of videos recorded during the experiment.The methods used to evaluate scratches produced by the claws of birds on the thermal papers presented some differences compared with the video analyses. These differences were caused mainly by differences in scatter, as any movement of the bird along the sloping walls of the funnel was recorded on the thermal paper, whereas video evaluations allowed us to detect single takeoff attempts by the birds and to consider only this behavior in the orientation analyses. Using computer vision, we were also able to identify and separately evaluate different behaviors that were impossible to record by the thermal paper.The traditional Emlen funnel is still the

  5. N-acetyltransferase (nat) is a critical conjunct of photoperiodism between the circadian system and endocrine axis in Antheraea pernyi.

    PubMed

    Mohamed, Ahmed A M; Wang, Qiushi; Bembenek, Jadwiga; Ichihara, Naoyuki; Hiragaki, Susumu; Suzuki, Takeshi; Takeda, Makio

    2014-01-01

    Since its discovery in 1923, the biology of photoperiodism remains a mystery in many ways. We sought the link connecting the circadian system to an endocrine switch, using Antheraea pernyi. PER-, CLK- and CYC-ir were co-expressed in two pairs of dorsolateral neurons of the protocerebrum, suggesting that these are the circadian neurons that also express melatonin-, NAT- and HIOMT-ir. The results suggest that a melatonin pathway is present in the circadian neurons. Melatonin receptor (MT2 or MEL-1B-R)-ir in PTTH-ir neurons juxtaposing clock neurons suggests that melatonin gates PTTH release. RIA showed a melatonin rhythm with a peak four hours after lights off in adult brain both under LD16:8 (LD) and LD12:12 (SD), and both the peak and the baseline levels were higher under LD than SD, suggesting a photoperiodic influence. When pupae in diapause were exposed to 10 cycles of LD, or stored at 4 °C for 4 months under constant darkness, an increase of NAT activity was observed when PTTH released ecdysone. DNA sequence upstream of nat contained E-boxes to which CYC/CLK could bind, and nat transcription was turned off by clk or cyc dsRNA. dsRNA(NAT) caused dysfunction of photoperiodism. dsRNA(PER) upregulated nat transcription as anticipated, based on findings in the Drosophila melanogaster circadian system. Transcription of nat, cyc and clk peaked at ZT12. RIA showed that dsRNA(NAT) decreased melatonin while dsRNA(PER) increased melatonin. Thus nat, a clock controlled gene, is the critical link between the circadian clock and endocrine switch. MT-binding may release PTTH, resulting in termination of diapause. This study thus examined all of the basic functional units from the clock: a photoperiodic counter as an accumulator of mRNA(NAT), to endocrine switch for photoperiodism in A. pernyi showing this system is self-complete without additional device especially for photoperiodism.

  6. N-acetyltransferase (nat) Is a Critical Conjunct of Photoperiodism between the Circadian System and Endocrine Axis in Antheraea pernyi

    PubMed Central

    Bembenek, Jadwiga; Hiragaki, Susumu; Suzuki, Takeshi; Takeda, Makio

    2014-01-01

    Since its discovery in 1923, the biology of photoperiodism remains a mystery in many ways. We sought the link connecting the circadian system to an endocrine switch, using Antheraea pernyi. PER-, CLK- and CYC-ir were co-expressed in two pairs of dorsolateral neurons of the protocerebrum, suggesting that these are the circadian neurons that also express melatonin-, NAT- and HIOMT-ir. The results suggest that a melatonin pathway is present in the circadian neurons. Melatonin receptor (MT2 or MEL-1B-R)-ir in PTTH-ir neurons juxtaposing clock neurons suggests that melatonin gates PTTH release. RIA showed a melatonin rhythm with a peak four hours after lights off in adult brain both under LD16∶8 (LD) and LD12∶12 (SD), and both the peak and the baseline levels were higher under LD than SD, suggesting a photoperiodic influence. When pupae in diapause were exposed to 10 cycles of LD, or stored at 4°C for 4 months under constant darkness, an increase of NAT activity was observed when PTTH released ecdysone. DNA sequence upstream of nat contained E-boxes to which CYC/CLK could bind, and nat transcription was turned off by clk or cyc dsRNA. dsRNANAT caused dysfunction of photoperiodism. dsRNAPER upregulated nat transcription as anticipated, based on findings in the Drosophila melanogaster circadian system. Transcription of nat, cyc and clk peaked at ZT12. RIA showed that dsRNANAT decreased melatonin while dsRNAPER increased melatonin. Thus nat, a clock controlled gene, is the critical link between the circadian clock and endocrine switch. MT-binding may release PTTH, resulting in termination of diapause. This study thus examined all of the basic functional units from the clock: a photoperiodic counter as an accumulator of mRNANAT, to endocrine switch for photoperiodism in A. pernyi showing this system is self-complete without additional device especially for photoperiodism. PMID:24667367

  7. Role of photoperiod and melatonin in seasonal acclimatization of the djungarian hamster, Phodopus sungorus

    NASA Astrophysics Data System (ADS)

    Steinlechner, S.; Heldmaier, G.

    1982-12-01

    The Djungarian hamster, Phodopus sungorus, shows a clear annual cycle in some thermogenic parameters such as nonshivering thermogenesis (NST) and cold resistance. These seasonal changes were found to be basically controlled by natural changes in photoperiod. Further support for this view was obtained by exposing the hamsters to artificial long and short photoperiods. Implantation of melatonin during fall and winter results in an increased thermogenic capacity in both short and long day hamsters comparable to that shown by values of control hamsters exposed to short photoperiods during winter. This thermotropic action of melatonin and of short photoperiod could be found only in fall and winter whereas during spring and summer, melatonin, like photoperiod, had no influence on thermogenic capacities. These results show that the actions of melatonin and photoperiod vary with the season and that they depend upon the photoperiodic history of the hamsters. Our results further indicate that the pineal gland with its hormone melatonin is involved in mediation of photoperiodic control of seasonal acclimatization.

  8. Effects of urbanization and recreation on songbirds

    Treesearch

    John M. Marzluff

    1997-01-01

    This chapter discusses how urbanization and recreation in Southwestern ponderosa pine forests might influence songbirds and comments on the research necessary to provide an assessment of future affects.

  9. Reproductive responses to photoperiod persist in olfactory bulbectomized Siberian hamsters (Phodopus sungorus).

    PubMed

    Prendergast, Brian J; Pyter, Leah M; Galang, Jerome; Kay, Leslie M

    2009-03-02

    In reproductively photoperiodic Syrian hamsters, removal of the olfactory bulbs (OBx) leads to a marked and sustained increase in gonadotrophin secretion which prevents normal testicular regression in short photoperiods. In contrast, among reproductively nonphotoperiodic laboratory strains of rats and mice, bulbectomy unmasks reproductive responses to photoperiod. The role of the olfactory bulbs has been proposed to have opposite effects on responsiveness to photoperiod, depending on the photoperiodicity of the reproductive system; however, Syrian hamsters are the only reproductively photoperiodic rodent species for which the role of the olfactory bulb in reproductive endocrinology has been assessed. This experiment evaluated the role of the olfactory bulbs in the photoperiodic control of reproduction in Siberian hamsters (Phodopus sungorus), an established model species for the study of neural substrates mediating seasonality. Relative to control hamsters housed in long days (15 h light/day), exposure of adult male hamsters to short days (9h light/day) for 8 weeks led to a temporal expansion of the pattern of nocturnal locomotor activity, testicular regression, decreases in testosterone (T) production, and undetectable levels of plasma follicle-stimulating hormone (FSH). Bilateral olfactory bulbectomy failed to affect any of these responses to short days. The patterns of entrainment to long and short days suggests that pre-pineal mechanisms involved in photoperiodic timekeeping are functioning normally in OBx hamsters. The absence of increases in FSH following bulbectomy in long days is incompatible with the hypothesis that the olfactory bulbs provide tonic inhibition of the HPG axis in this species. In marked contrast to Syrian hamsters, the olfactory bulbs of Siberian hamsters play essentially no role in the modulation of tonic gonadotrophin production or gonadotrophin responses to photoperiod.

  10. Deep-brain photoreceptors (DBPs) involved in the photoperiodic gonadal response in an avian species, Gallus gallus.

    PubMed

    Kang, Seong W; Kuenzel, Wayne J

    2015-01-15

    Three primitive photoreceptors [melanopsin (Opn4), neuropsin/opsin5 (Opn5) and vertebrate ancient opsin (VAOpn)] were reported as possible avian deep-brain photoreceptors (DBPs) involved in the perception of photoperiodic information affecting the onset and development of reproduction. The objective of this study was to determine the effect of long-day photostimulation and/or sulfamethazine treatment (SMZ, a compound known to advance light-induced testes development) on gene expression of DBPs and key hypothalamic and pituitary genes involved in avian reproductive function. Two-week old chicks were randomly selected into four experimental groups: short-day control (SC, LD8:16), short-day+SMZ (SS, LD8:16, 0.2% diet SMZ), long-day control (LC, LD16:8), and long-day+SMZ (LS, LD16:8, 0.2% diet SMZ). Birds were sampled on days 3, 7, and 28 after initiation of a long-day photoperiod and/or SMZ dietary treatments. Three brain regions [septal-preoptic, anterior hypothalamic (SepPre/Ant-Hypo) region, mid-hypothalamic (Mid-Hypo) region, posterior-hypothalamic (Post-Hypo) region], and anterior pituitary gland were dissected. Using quantitative real-time RT-PCR, we determined changes of expression levels of genes in distinct brain regions; Opn4 and Opn5 in SepPre/Ant-Hypo and Post-Hypo regions and, VAOpn in the Mid-Hypo region. Long-day treatment resulted in a significantly elevated testes weight on days 7 and 28 compared to controls, and SMZ augmented testes weight in both short- and long-day treatment after day 7 (P<0.05). Long-day photoperiodic treatment on the third day unexpectedly induced a large 8.4-fold increase of VAOpn expression in the Mid-Hypo region, a 15.4-fold increase of Opn4 and a 97.8-fold increase of Opn5 gene expression in the Post-Hypo region compared to SC birds (P<0.01). In contrast, on days 7 and 28, gene expression of the three DBPs was barely detectable. LC group showed a significant increase in GnRH-1 and TRH mRNA in the Mid-Hypo compared to SC on

  11. Vocal babbling in songbirds requires the basal ganglia-recipient motor thalamus but not the basal ganglia

    PubMed Central

    Goldberg, Jesse H.

    2011-01-01

    Young songbirds produce vocal “babbling,” and the variability of their songs is thought to underlie a process of trial-and-error vocal learning. It is known that this exploratory variability requires the “cortical” component of a basal ganglia (BG) thalamocortical loop, but less understood is the role of the BG and thalamic components in this behavior. We found that large bilateral lesions to the songbird BG homolog Area X had little or no effect on song variability during vocal babbling. In contrast, lesions to the BG-recipient thalamic nucleus DLM (medial portion of the dorsolateral thalamus) largely abolished normal vocal babbling in young birds and caused a dramatic increase in song stereotypy. These findings support the idea that the motor thalamus plays a key role in the expression of exploratory juvenile behaviors during learning. PMID:21430276

  12. An IACUC Perspective on Songbirds and Their Use in Neurobiological Research

    PubMed Central

    Schmidt, Marc F.

    2011-01-01

    Laboratory research using songbirds as a model system for investigating basic questions of neurobiological function has expanded rapidly and recently, with approximately 120 laboratories working with songbirds worldwide. In the United States alone, of the approximately 80 such laboratories nearly a third have been established in the past 10 years. Yet many animal facilities are not outfitted to manage these animals, and as a consequence laboratories often use alternative housing arrangements established by institutional animal care and use committees (IACUCs). These committees invariably differ in their expertise level with birds and thus guidelines also vary considerably from one institution to another. In this article I address a number of factors to consider for effective oversight of research involving songbirds. PMID:21131718

  13. Photoperiodic Control of Carbon Distribution during the Floral Transition in Arabidopsis[C][W][OPEN

    PubMed Central

    Ortiz-Marchena, M. Isabel; Albi, Tomás; Lucas-Reina, Eva; Said, Fatima E.; Romero-Campero, Francisco J.; Cano, Beatriz; Ruiz, M. Teresa; Romero, José M.; Valverde, Federico

    2014-01-01

    Flowering is a crucial process that demands substantial resources. Carbon metabolism must be coordinated with development through a control mechanism that optimizes fitness for any physiological need and growth stage of the plant. However, how sugar allocation is controlled during the floral transition is unknown. Recently, the role of a CONSTANS (CO) ortholog (Cr-CO) in the control of the photoperiod response in the green alga Chlamydomonas reinhardtii and its influence on starch metabolism was demonstrated. In this work, we show that transitory starch accumulation and glycan composition during the floral transition in Arabidopsis thaliana are regulated by photoperiod. Employing a multidisciplinary approach, we demonstrate a role for CO in regulating the level and timing of expression of the GRANULE BOUND STARCH SYNTHASE (GBSS) gene. Furthermore, we provide a detailed characterization of a GBSS mutant involved in transitory starch synthesis and analyze its flowering time phenotype in relation to its altered capacity to synthesize amylose and to modify the plant free sugar content. Photoperiod modification of starch homeostasis by CO may be crucial for increasing the sugar mobilization demanded by the floral transition. This finding contributes to our understanding of the flowering process. PMID:24563199

  14. Effects of photoperiod on wheat growth, development and yield in CELSS

    NASA Astrophysics Data System (ADS)

    Yunze, Shen; Shuangsheng, Guo

    2014-12-01

    A Controlled Ecological Life Support System (CELSS) is a sealed system used in spaceflight in order to provide astronauts with food and O2 by plants. It is of great significance to increase the energy-using efficiency because energy is extremely deficient in the space. Therefore, the objective of this research was to increase the energy-using efficiency of wheat by regulating the photoperiod. Sixteen treatments were set in total: four photoperiods before flowering (PBF) combined with four photoperiods after flowering (PAF) of 12 h, 16 h, 20 h and 24 h. The light source was red-blue LED (90% red+10% blue). As a result, the growth period of wheat was largely extended by shorter PBF, particularly the number of days from tillering to jointing and from jointing to heading. The period from flowering to maturity was extended by shorter PAF. Shorter PBF and longer PAF could increase not only the yield but also the energy-using efficiency of wheat. As for the nutritional quality, longer photoperiod (both PBF and PAF) increased starch concentration as well as decreased protein concentration of seeds. The effects of PBF and PAF were interactional. The lighting strategy with PBF of 12 h and PAF of 24 h was proved to be the optimum photoperiod for wheat cultivation in CELSS. The mechanisms of photoperiod effect contain two aspects. Firstly, photoperiod is a signal for many processes in plant growth, particularly the process of ear differentiation. Shorter PBF promoted the ear differentiation of wheat, increasing the spikelet number, floret number and seed number and thus enhancing the yield. Secondly, longer photoperiod leads to more light energy input and longer time of photosynthesis, so that longer PAF provided more photosynthate and increased seed yield.

  15. Finding the Beat: From Socially Coordinated Vocalizations in Songbirds to Rhythmic Entrainment in Humans.

    PubMed

    Benichov, Jonathan I; Globerson, Eitan; Tchernichovski, Ofer

    2016-01-01

    Humans and oscine songbirds share the rare capacity for vocal learning. Songbirds have the ability to acquire songs and calls of various rhythms through imitation. In several species, birds can even coordinate the timing of their vocalizations with other individuals in duets that are synchronized with millisecond-accuracy. It is not known, however, if songbirds can perceive rhythms holistically nor if they are capable of spontaneous entrainment to complex rhythms, in a manner similar to humans. Here we review emerging evidence from studies of rhythm generation and vocal coordination across songbirds and humans. In particular, recently developed experimental methods have revealed neural mechanisms underlying the temporal structure of song and have allowed us to test birds' abilities to predict the timing of rhythmic social signals. Surprisingly, zebra finches can readily learn to anticipate the calls of a "vocal robot" partner and alter the timing of their answers to avoid jamming, even in reference to complex rhythmic patterns. This capacity resembles, to some extent, human predictive motor response to an external beat. In songbirds, this is driven, at least in part, by the forebrain song system, which controls song timing and is essential for vocal learning. Building upon previous evidence for spontaneous entrainment in human and non-human vocal learners, we propose a comparative framework for future studies aimed at identifying shared mechanism of rhythm production and perception across songbirds and humans.

  16. Variation in social relationships relates to song preferences and EGR1 expression in a female songbird.

    PubMed

    Schubloom, Hannah E; Woolley, Sarah C

    2016-09-01

    Social experiences can profoundly shape social behavior and the underlying neural circuits. Across species, the formation of enduring social relationships is associated with both neural and behavioral changes. However, it remains unclear how longer-term relationships between individuals influence brain and behavior. Here, we investigated how variation in social relationships relates to variation in female preferences for and neural responses to song in a pair-bonding songbird. We assessed variation in the interactions between individuals in male-female zebra finch pairs and found that female preferences for their mate's song were correlated with the degree of affiliation and amount of socially modulated singing, but not with the frequency of aggressive interactions. Moreover, variation in measures of pair quality and preference correlated with variation in the song-induced expression of EGR1, an immediate early gene related to neural activity and plasticity, in brain regions important for auditory processing and social behavior. For example, females with weaker preferences for their mate's song had greater EGR1 expression in the nucleus Taeniae, the avian homologue of the mammalian medial amygdala, in response to playback of their mate's courtship song. Our data indicate that the quality of social interactions within pairs relates to variation in song preferences and neural responses to ethologically relevant stimuli and lend insight into neural circuits sensitive to social information. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1029-1040, 2016. © 2016 Wiley Periodicals, Inc.

  17. Photoperiodic Regulation of the Orexigenic Effects of Ghrelin in Siberian Hamsters

    PubMed Central

    Bradley, Sean P.; Pattullo, Lucia M.; Patel, Priyesh N.; Prendergast, Brian J.

    2010-01-01

    Animals living in temperate climates with predictable seasonal changes in food availability may use seasonal information to engage different metabolic strategies. Siberian hamsters decrease costs of thermoregulation during winter by reducing food intake and body mass in response to decreasing or short day lengths (SD). These experiments examined whether SD reductions in food intake in hamsters is driven, at least in part, by altered behavioral responses to ghrelin, a gut-derived orexigenic peptide which induces food intake via NPY-dependent mechanisms. Relative to hamsters housed in long day (LD) photoperiods, SD hamsters consumed less food in response to i.p. treatment with ghrelin across a range of doses from 0.03 to 3 mg/kg. To determine whether changes in photoperiod alter behavioral responses ghrelin-induced activation of NPY neurons, c-Fos and NPY expression were quantified in the arcuate nucleus (ARC) via double-label fluorescent immunocytochemistry following i.p. treatment with 0.3 mg/kg ghrelin or saline. Ghrelin induced c-Fos immunoreactivity (-ir) in a greater proportion of NPY-ir neurons of LD relative to SD hamsters. In addition, following ghrelin treatment, a greater proportion of ARC c-Fos-ir neurons were identifiable as NPY-ir in LD relative to SD hamsters. Changes in day length markedly alter the behavioral response to ghrelin. The data also identify photoperiod-induced changes in the ability of ghrelin to activate ARC NPY neurons as a possible mechanism by which changes in day length alter food intake. PMID:20600050

  18. Seasonality in a temperate zone bird can be entrained by near equatorial photoperiods.

    PubMed

    Dawson, Alistair

    2007-03-07

    Birds use photoperiod to control the time of breeding and moult. However, it is unclear whether responses are dependent on absolute photoperiod, the direction and rate of change in photoperiod, or if photoperiod entrains a circannual clock. If starlings (Sturnus vulgaris) are kept on a constant photoperiod of 12h light:12h darkness per day (12L:12D), then they can show repeated cycles of gonadal maturation, regression and moult, which is evidence for a circannual clock. In this study, starlings kept on constant 11.5L:12.5D for 4 years or 12.5L:11.5D for 3 years showed no circannual cycles in gonadal maturation or moult. So, if there is a circannual clock, it is overridden by a modest deviation in photoperiod from 12L:12D. The responses to 11.5L:12.5D and 12.5L:11.5D were very different, the former perceived as a short photoperiod (birds were photosensitive for most of the time) and the latter as a long photoperiod (birds remained permanently photorefractory). Starlings were then kept on a schedule which ranged from 11.5L:12.5D in mid-winter to 12.5L:11.5D in mid-summer (simulating the annual cycle at 9 degrees N) for 3 years. These birds entrained precisely to calendar time and changes in testicular size and moult were similar to those of birds under a simulated cycle at 52 degrees N. These data show that birds are very sensitive to changes in photoperiod but that they do not simply respond to absolute photoperiod nor can they rely on a circannual clock. Instead, birds appear to respond to the shape of the annual change in photoperiod. This proximate control could operate from near equatorial latitudes and would account for similar seasonal timing in individuals of a species over a wide range of latitudes.

  19. Transfer from long to short photoperiods affects production efficiency of day-neutral rice

    NASA Technical Reports Server (NTRS)

    Goldman, K. R.; Mitchell, C. A.

    1999-01-01

    The day-neutral, semidwarf rice (Oryza sativa L.) cultivar Ai-Nan-Tsao was grown in a greenhouse under summer conditions using high-pressure sodium lamps to extend the natural photoperiod. After allowing 2 weeks for germination, stand establishment, and thinning to a consistent planting density of 212 plants/m2, stands were maintained under continuous lighting for 35 or 49 days before shifting to 8- or 12-h photoperiods until harvest 76 days after planting. Non-shifted control treatments consisting of 8-, 12-, or 24-h photoperiods also were maintained throughout production. Tiller number increased as duration of exposure to continuous light increased before shifting to shorter photoperiods. However, shoot harvest index and yield efficiency rate were lower for all plants receiving continuous light than for those under the 8- or 12-h photoperiods. Stands receiving 12-h photoperiods throughout production had the highest grain yield per plant and equaled the 8-h-photoperiod control plants for the lowest tiller number per plant. As long as stands were exposed to continuous light, tiller formation continued. Shifting to shorter photoperiods late in the cropping cycle resulted in newly formed tillers that were either sterile or unable to mature grain before harvest. Late-forming tillers also suppressed yield of grain in early-forming tillers, presumably by competing for photosynthate or for remobilized assimilate during senescence. Stands receiving 12-h photoperiods throughout production not only produced the highest grain yield at harvest but had the highest shoot harvest index, which is important for resource-recovery strategies in advanced life-support systems proposed for space.

  20. Adaptive strategies in nocturnally migrating insects and songbirds: contrasting responses to wind.

    PubMed

    Chapman, Jason W; Nilsson, Cecilia; Lim, Ka S; Bäckman, Johan; Reynolds, Don R; Alerstam, Thomas

    2016-01-01

    Animals that use flight as their mode of transportation must cope with the fact that their migration and orientation performance is strongly affected by the flow of the medium they are moving in, that is by the winds. Different strategies can be used to mitigate the negative effects and benefit from the positive effects of a moving flow. The strategies an animal can use will be constrained by the relationship between the speed of the flow and the speed of the animal's own propulsion in relation to the surrounding air. Here we analyse entomological and ornithological radar data from north-western Europe to investigate how two different nocturnal migrant taxa, the noctuid moth Autographa gamma and songbirds, deal with wind by analysing variation in resulting flight directions in relation to the wind-dependent angle between the animal's heading and track direction. Our results, from fixed locations along the migratory journey, reveal different global strategies used by moths and songbirds during their migratory journeys. As expected, nocturnally migrating moths experienced a greater degree of wind drift than nocturnally migrating songbirds, but both groups were more affected by wind in autumn than in spring. The songbirds' strategies involve elements of both drift and compensation, providing some benefits from wind in combination with destination and time control. In contrast, moths expose themselves to a significantly higher degree of drift in order to obtain strong wind assistance, surpassing the songbirds in mean ground speed, at the cost of a comparatively lower spatiotemporal migratory precision. Moths and songbirds show contrasting but adaptive responses to migrating through a moving flow, which are fine-tuned to the respective flight capabilities of each group in relation to the wind currents they travel within. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  1. Effect of white-tailed deer on songbirds within managed forests in Pennsylvania

    Treesearch

    David S. deCalesta

    1994-01-01

    White-tailed deer (Odocoileus virginianus) populations have been maintained at high densities in Pennsylvania for several decades with unknown effects on songbirds and their habitats. I evaluated effects of white-tailed deer density on songbird species richness, abundance, and habitat. I simulated 4 deer densities (3.7, 7.9, 14.9, and 24.9 deer/km...

  2. Lunar phase-dependent expression of cryptochrome and a photoperiodic mechanism for lunar phase-recognition in a reef fish, goldlined spinefoot.

    PubMed

    Fukushiro, Masato; Takeuchi, Takahiro; Takeuchi, Yuki; Hur, Sung-Pyo; Sugama, Nozomi; Takemura, Akihiro; Kubo, Yoko; Okano, Keiko; Okano, Toshiyuki

    2011-01-01

    Lunar cycle-associated physiology has been found in a wide variety of organisms. Recent study has revealed that mRNA levels of Cryptochrome (Cry), one of the circadian clock genes, were significantly higher on a full moon night than on a new moon night in coral, implying the involvement of a photoreception system in the lunar-synchronized spawning. To better establish the generalities surrounding such a mechanism and explore the underlying molecular mechanism, we focused on the relationship between lunar phase, Cry gene expression, and the spawning behavior in a lunar-synchronized spawner, the goldlined spinefoot (Siganus guttatus), and we identified two kinds of Cry genes in this animal. Their mRNA levels showed lunar cycle-dependent expression in the medial part of the brain (mesencephalon and diencephalon) peaking at the first quarter moon. Since this lunar phase coincided with the reproductive phase of the goldlined spinefoot, Cry gene expression was considered a state variable in the lunar phase recognition system. Based on the expression profiles of SgCrys together with the moonlight's pattern of timing and duration during its nightly lunar cycle, we have further speculated on a model of lunar phase recognition for reproductive control in the goldlined spinefoot, which integrates both moonlight and circadian signals in a manner similar to photoperiodic response.

  3. Photoperiod-Dependent Effects of 4-tert-Octylphenol on Adherens and Gap Junction Proteins in Bank Vole Seminiferous Tubules

    PubMed Central

    Kuras, Paulina; Lydka-Zarzycka, Marta; Bilinska, Barbara

    2013-01-01

    In the present study we evaluated in vivo and in vitro effects of 4-tert-octylphenol (OP) on the expression and distribution of adherens and gap junction proteins, N-cadherin, β-catenin, and connexin 43 (Cx43), in testes of seasonally breeding rodents, bank voles. We found that in bank vole testes expression and distribution of N-cadherin, β-catenin, and Cx43 were photoperiod dependent. Long-term treatment with OP (200 mg/kg b.w.) resulted in the reduction of junction proteins expressions (P < 0.05, P < 0.01) and their delocalization in the testes of males kept in long photoperiod, whereas in short-day animals slight increase of Cx43 (P < 0.05), N-cadherin, and β-catenin (statistically nonsignificant) levels was observed. Effects of OP appeared to be independent of FSH and were maintained during in vitro organ culture, indicating that OP acts directly on adherens and gap junction proteins in the testes. An experiment performed using an antiestrogen ICI 182,780 demonstrated that the biological effects of OP on β-catenin and Cx43 involve an estrogen receptor-mediated response. Taken together, in bank vole organization of adherens and gap junctions and their susceptibility to OP are related to the length of photoperiod. Alterations in cadherin/catenin and Cx43-based junction may partially result from activation of estrogen receptor α and/or β signaling pathway. PMID:23737770

  4. Social Status Affects the Degree of Sex Difference in the Songbird Brain

    PubMed Central

    Voigt, Cornelia; Gahr, Manfred

    2011-01-01

    It is thought that neural sex differences are functionally related to sex differences in the behaviour of vertebrates. A prominent example is the song control system of songbirds. Inter-specific comparisons have led to the hypothesis that sex differences in song nuclei size correlate with sex differences in song behaviour. However, only few species with similar song behaviour in both sexes have been investigated and not all data fit the hypothesis. We investigated the proposed structure – function relationship in a cooperatively breeding and duetting songbird, the white-browed sparrow weaver (Plocepasser mahali). This species lives in groups of 2–10 individuals, with a dominant breeding pair and male and female subordinates. While all male and female group members sing duet and chorus song, a male, once it has reached the dominant position in the group, sings an additional type of song that comprises a distinct and large syllable repertoire. Here we show for both types of male – female comparisons a male-biased sex difference in neuroanatomy of areas of the song production pathway (HVC and RA) that does not correlate with the observed polymorphism in song behaviour. In contrast, in situ hybridisation of mRNA of selected genes expressed in the song nucleus HVC reveals a gene expression pattern that is either similar between sexes in female – subordinate male comparisons or female-biased in female – dominant male comparisons. Thus, the polymorphic gene expression pattern would fit the sex- and status-related song behaviour. However, this implies that once a male has become dominant it produces the duetting song with a different neural phenotype than subordinate males. PMID:21687671

  5. Seasonality in a temperate zone bird can be entrained by near equatorial photoperiods

    PubMed Central

    Dawson, Alistair

    2006-01-01

    Birds use photoperiod to control the time of breeding and moult. However, it is unclear whether responses are dependent on absolute photoperiod, the direction and rate of change in photoperiod, or if photoperiod entrains a circannual clock. If starlings (Sturnus vulgaris) are kept on a constant photoperiod of 12 h light : 12 h darkness per day (12 L : 12 D), then they can show repeated cycles of gonadal maturation, regression and moult, which is evidence for a circannual clock. In this study, starlings kept on constant 11.5 L : 12.5 D for 4 years or 12.5 L : 11.5 D for 3 years showed no circannual cycles in gonadal maturation or moult. So, if there is a circannual clock, it is overridden by a modest deviation in photoperiod from 12 L : 12 D. The responses to 11.5 L : 12.5 D and 12.5 L : 11.5 D were very different, the former perceived as a short photoperiod (birds were photosensitive for most of the time) and the latter as a long photoperiod (birds remained permanently photorefractory). Starlings were then kept on a schedule which ranged from 11.5 L : 12.5 D in mid-winter to 12.5 L : 11.5 D in mid-summer (simulating the annual cycle at 9 °N) for 3 years. These birds entrained precisely to calendar time and changes in testicular size and moult were similar to those of birds under a simulated cycle at 52 °N. These data show that birds are very sensitive to changes in photoperiod but that they do not simply respond to absolute photoperiod nor can they rely on a circannual clock. Instead, birds appear to respond to the shape of the annual change in photoperiod. This proximate control could operate from near equatorial latitudes and would account for similar seasonal timing in individuals of a species over a wide range of latitudes. PMID:17254997

  6. Photoperiod- and Triiodothyronine-dependent Regulation of Reproductive Neuropeptides, Proinflammatory Cytokines, and Peripheral Physiology in Siberian Hamsters (Phodopus sungorus).

    PubMed

    Banks, Ruth; Delibegovic, Mirela; Stevenson, Tyler J

    2016-06-01

    Seasonal trade-offs in reproduction and immunity are ubiquitous in nature. The mechanisms that govern transitions across seasonal physiological states appear to involve reciprocal switches in the local synthesis of thyroid hormone. In long-day (LD) summer-like conditions, increased hypothalamic triiodothyronine (T3) stimulates gonadal development. Alternatively, short-day (SD) winter-like conditions increase peripheral leukocytes and enhance multiple aspects of immune function. These data indicate that the localized effects of T3 in the hypothalamus and leukocytes are photoperiod dependent. We tested the hypothesis that increased peripheral T3 in SD conditions would increase aspects of reproductive physiology and inhibit immune function, whereas T3 injections in LD conditions would facilitate aspects of immune function (i.e., leukocytes). In addition, we also examined whether T3 regulates hypothalamic neuropeptide expression as well as hypothalamic and splenic proinflammatory cytokine expression. Adult male Siberian hamsters were maintained in LD (15L:9D) or transferred to SD (9L:15D) for 8 weeks. A subset of LD and SD hamsters was treated daily with 5 µg T3 for 2 weeks. LD and SD controls were injected with saline. Daily T3 administration in SD hamsters (SD+T3) resulted in a rapid and substantial decrease in peripheral leukocyte concentrations and stimulated gonadal development. T3 treatment in LD (LD+T3) had no effect on testicular volumes but significantly increased leukocyte concentrations. Molecular analyses revealed that T3 stimulated interleukin 1β messenger RNA (mRNA) expression in the spleen and inhibited RFamide Related Peptide-3 mRNA expression in the hypothalamus. Moreover, there was a photoperiod-dependent decrease in splenic tumor necrosis factor-α mRNA expression. These findings reveal that T3 has tissue-specific and photoperiod-dependent regulation of seasonal rhythms in reproduction and immune function. © 2016 The Author(s).

  7. Detection ratios of riparian songbirds

    Treesearch

    Susan L. Earnst; Jeannie Heltzel

    2005-01-01

    This paper presents preliminary results from the first year of a two-year study designed to evaluate bias in a typical songbird survey by examining differences in detection ratios among species, cover types, and time of the season. Detection ratios, calculated as number of individuals detected during a 15-25 minute fixed-width transect survey divided by the number of...

  8. QTL mapping for flowering-time and photoperiod insensitivity of cotton Gossypium darwinii Watt.

    PubMed

    Kushanov, Fakhriddin N; Buriev, Zabardast T; Shermatov, Shukhrat E; Turaev, Ozod S; Norov, Tokhir M; Pepper, Alan E; Saha, Sukumar; Ulloa, Mauricio; Yu, John Z; Jenkins, Johnie N; Abdukarimov, Abdusattor; Abdurakhmonov, Ibrokhim Y

    2017-01-01

    Most wild and semi-wild species of the genus Gossypium are exhibit photoperiod-sensitive flowering. The wild germplasm cotton is a valuable source of genes for genetic improvement of modern cotton cultivars. A bi-parental cotton population segregating for photoperiodic flowering was developed by crossing a photoperiod insensitive irradiation mutant line with its pre-mutagenesis photoperiodic wild-type G. darwinii Watt genotype. Individuals from the F2 and F3 generations were grown with their parental lines and F1 hybrid progeny in the long day and short night summer condition (natural day-length) of Uzbekistan to evaluate photoperiod sensitivity, i.e., flowering-time during the seasons 2008-2009. Through genotyping the individuals of this bi-parental population segregating for flowering-time, linkage maps were constructed using 212 simple-sequence repeat (SSR) and three cleaved amplified polymorphic sequence (CAPS) markers. Six QTLs directly associated with flowering-time and photoperiodic flowering were discovered in the F2 population, whereas eight QTLs were identified in the F3 population. Two QTLs controlling photoperiodic flowering and duration of flowering were common in both populations. In silico annotations of the flanking DNA sequences of mapped SSRs from sequenced cotton (G. hirsutum L.) genome database has identified several potential 'candidate' genes that are known to be associated with regulation of flowering characteristics of plants. The outcome of this research will expand our understanding of the genetic and molecular mechanisms of photoperiodic flowering. Identified markers should be useful for marker-assisted selection in cotton breeding to improve early flowering characteristics.

  9. Songbirds as sentinels of mercury in terrestrial habitats of eastern North America.

    PubMed

    Jackson, Allyson K; Evers, David C; Adams, Evan M; Cristol, Daniel A; Eagles-Smith, Collin; Edmonds, Samuel T; Gray, Carrie E; Hoskins, Bart; Lane, Oksana P; Sauer, Amy; Tear, Timothy

    2015-03-01

    Mercury (Hg) is a globally distributed environmental contaminant with a variety of deleterious effects in fish, wildlife, and humans. Breeding songbirds may be useful sentinels for Hg across diverse habitats because they can be effectively sampled, have well-defined and small territories, and can integrate pollutant exposure over time and space. We analyzed blood total Hg concentrations from 8,446 individuals of 102 species of songbirds, sampled on their breeding territories across 161 sites in eastern North America [geometric mean Hg concentration = 0.25 μg/g wet weight (ww), range <0.01-14.60 μg/g ww]. Our records span an important time period-the decade leading up to implementation of the USEPA Mercury and Air Toxics Standards, which will reduce Hg emissions from coal-fired power plants by over 90 %. Mixed-effects modeling indicated that habitat, foraging guild, and age were important predictors of blood Hg concentrations across species and sites. Blood Hg concentrations in adult invertebrate-eating songbirds were consistently higher in wetland habitats (freshwater or estuarine) than upland forests. Generally, adults exhibited higher blood Hg concentrations than juveniles within each habitat type. We used model results to examine species-specific differences in blood Hg concentrations during this time period, identifying potential Hg sentinels in each region and habitat type. Our results present the most comprehensive assessment of blood Hg concentrations in eastern songbirds to date, and thereby provide a valuable framework for designing and evaluating risk assessment schemes using sentinel songbird species in the time after implementation of the new atmospheric Hg standards.

  10. Can hedgerow management mitigate the impacts of predation on songbird nest survival?

    PubMed

    Dunn, Jenny C; Gruar, Derek; Stoate, Chris; Szczur, John; Peach, Will J

    2016-12-15

    Nest predators can have significant impacts on songbird reproductive success. These impacts may be amplified by habitat simplification and here we test whether sympathetic management of farmland hedgerows can reduce nest depredation, especially by corvids. We test whether songbirds select nest sites according to structural features of hedgerows (including nest visibility and accessibility), and whether these features influence nest predation risk. Songbirds selected nesting sites affording higher vegetation cover above the nest, increased visibility on the nest-side of the hedgerow and reduced visibility on the far side of the hedge. Nest survival was unrelated to corvid abundance and only weakly related (at the egg stage) to corvid nest proximity. Nest survival at the chick stage was higher where vegetation structure restricted access to corvid-sized predators (averaging 0.78 vs. 0.53), and at nests close to potential vantage points. Overall nest survival was sensitive to hedgerow structure (accessibility) particularly at low exposure to corvid predation, while the overall impact of corvid exposure was dependent on the relationship involving proximity to vantage points. Nest survival over the chick stage was much higher (0.67) in stock-proof, trimmed and mechanically cut hedgerows, (which tended to provide lower side visibility and accessibility) than in recently laid, remnant or leggy hedgerows (0.18). Long-term reductions in the management of British hedgerows may therefore be exposing nesting songbirds to increased predation risk. We recommend regular rotational cutting of hedgerows to maintain a dense woody structure and thereby reduce songbird nest predation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Toxic exposure of songbirds to lead in the Southeast Missouri Lead Mining District.

    PubMed

    Beyer, W Nelson; Franson, J Christian; French, John B; May, Thomas; Rattner, Barnett A; Shearn-Bochsler, Valerie I; Warner, Sarah E; Weber, John; Mosby, David

    2013-10-01

    Mining and smelting in the Southeast Missouri Lead Mining District has caused widespread contamination of soils with lead (Pb) and other metals. Soils from three study sites sampled in the district contained from approximately 1,000-3,200 mg Pb/kg. Analyses of earthworms [33-4,600 mg Pb/kg dry weight (dw)] collected in the district showed likely high Pb exposure of songbirds preying on soil organisms. Mean tissue Pb concentrations in songbirds collected from the contaminated sites were greater (p < 0.05) than those in songbirds from reference sites by factors of 8 in blood, 13 in liver, and 23 in kidney. Ranges of Pb concentrations in livers (mg Pb/kg dw) were as follows: northern cardinal (Cardinalis cardinalis) = 0.11-3.0 (reference) and 1.3-30 (contaminated) and American robin (Turdus migratorius) = 0.43-8.5 (reference) and 7.6-72 (contaminated). Of 34 adult and juvenile songbirds collected from contaminated sites, 11 (32%) had hepatic Pb concentrations that were consistent with adverse physiological effects, 3 (9%) with systemic toxic effects, and 4 (12%) with life-threatening toxic effects. Acid-fast renal intranuclear inclusion bodies, which are indicative of Pb poisoning, were detected in kidneys of two robins that had the greatest renal Pb concentrations (952 and 1,030 mg/kg dw). Mean activity of the enzyme delta-aminolevulinic acid dehydratase (ALAD) in red blood cells, a well-established bioindicator of Pb poisoning in birds, was decreased by 58-82% in songbirds from the mining sites. We conclude that habitats within the mining district with soil Pb concentrations of ≥1,000 mg Pb/kg are contaminated to the extent that they are exposing ground-feeding songbirds to toxic concentrations of Pb.

  12. Toxic exposure of songbirds to lead in the Southeast Missouri Lead Mining District

    USGS Publications Warehouse

    Beyer, W. Nelson; Franson, J. Christian; French, John B.; May, Thomas; Rattner, Barnett A.; Shearn-Bochsler, Valerie I.; Warner, Sarah E.; Weber, John; Mosby, David

    2013-01-01

    Mining and smelting in the Southeast Missouri Lead Mining District has caused widespread contamination of soils with lead (Pb) and other metals. Soils from three study sites sampled in the district contained from approximately 1,000–3,200 mg Pb/kg. Analyses of earthworms [33–4,600 mg Pb/kg dry weight (dw)] collected in the district showed likely high Pb exposure of songbirds preying on soil organisms. Mean tissue Pb concentrations in songbirds collected from the contaminated sites were greater (p < 0.05) than those in songbirds from reference sites by factors of 8 in blood, 13 in liver, and 23 in kidney. Ranges of Pb concentrations in livers (mg Pb/kg dw) were as follows: northern cardinal (Cardinalis cardinalis) = 0.11–3.0 (reference) and 1.3–30 (contaminated) and American robin (Turdus migratorius) = 0.43–8.5 (reference) and 7.6–72 (contaminated). Of 34 adult and juvenile songbirds collected from contaminated sites, 11 (32 %) had hepatic Pb concentrations that were consistent with adverse physiological effects, 3 (9 %) with systemic toxic effects, and 4 (12 %) with life-threatening toxic effects. Acid-fast renal intranuclear inclusion bodies, which are indicative of Pb poisoning, were detected in kidneys of two robins that had the greatest renal Pb concentrations (952 and 1,030 mg/kg dw). Mean activity of the enzyme delta-aminolevulinic acid dehydratase (ALAD) in red blood cells, a well-established bioindicator of Pb poisoning in birds, was decreased by 58–82 % in songbirds from the mining sites. We conclude that habitats within the mining district with soil Pb concentrations of ≥1,000 mg Pb/kg are contaminated to the extent that they are exposing ground-feeding songbirds to toxic concentrations of Pb.

  13. The Pea Photoperiod Response Gene STERILE NODES Is an Ortholog of LUX ARRHYTHMO1[W][OPEN

    PubMed Central

    Liew, Lim Chee; Hecht, Valérie; Sussmilch, Frances C.; Weller, James L.

    2014-01-01

    The STERILE NODES (SN) locus in pea (Pisum sativum) was one of the first photoperiod response genes to be described and provided early evidence for the genetic control of long-distance signaling in flowering-time regulation. Lines homozygous for recessive sn mutations are early flowering and photoperiod insensitive, with an increased ability to promote flowering across a graft union in short-day conditions. Here, we show that SN controls developmental regulation of genes in the FT family and rhythmic regulation of genes related to circadian clock function. Using a positional and functional candidate approach, we identify SN as the pea ortholog of LUX ARRHYTHMO, a GARP transcription factor from Arabidopsis (Arabidopsis thaliana) with an important role in circadian clock function. In addition to induced mutants, sequence analysis demonstrates the presence of at least three other independent, naturally occurring loss-of-function mutations among known sn cultivars. Examination of genetic and regulatory interactions between SN and two other circadian clock genes, HIGH RESPONSE TO PHOTOPERIOD (HR) and DIE NEUTRALIS (DNE), suggests a complex relationship in which HR regulates expression of SN and the role of DNE and HR in control of flowering is dependent on SN. These results extend previous work to show that pea orthologs of all three Arabidopsis evening complex genes regulate clock function and photoperiod-responsive flowering and suggest that the function of these genes may be widely conserved. PMID:24706549

  14. Effects of photoperiod on boll weevil (Coleoptera: Curculionidae) development, survival, and reproduction.

    PubMed

    Greenberg, S M; Sappington, T W; Adamczyk, J J; Liu, T-X; Setamou, M

    2008-12-01

    Effects of photoperiod on development, survival, feeding, and oviposition of boll weevils, Anthonomus grandis grandis Boheman, were assessed under five different photophases (24, 14, 12, 10, and 0 h) at a constant 27 degrees C temperature and 65% RH in the laboratory. Analyses of our results detected positive relationships between photoperiod and puncturing (mean numbers of oviposition and feeding punctures per day), and oviposition (oviposition punctures/oviposition+feeding punctures) activities, and the proportion of squares attacked by boll weevil females. When boll weevil females developed in light:darkness cycles, they produced a significantly higher percentage of eggs developing to adulthood than those developed in 24-h light or dark conditions. In long photoperiod (24:0 and 14:10 h), the number of female progeny was significantly higher and their development time was significantly shorter than those developed in short photoperiod (0:24 and 10:14 h). Lifetime oviposition was significantly highest at 12- and 14-h photophase, lowest at 0- and 10-h photophase, and intermediate at 24 h of light. Life table calculations indicated that boll weevil populations developed in a photoperiod of 14:10 and 12:12 (L:D) h will increase an average of two-fold each generation (Ro) compared with boll weevils developed in 24:0- and 10:14-h photoperiods and 15-fold compared with those at 0:24 h. Knowledge of the photoperiod-dependent population growth potential is critical for understanding population dynamics to better develop sampling protocols and timing insecticide applications.

  15. Evolution of photoperiod sensing in plants and algae.

    PubMed

    Serrano-Bueno, Gloria; Romero-Campero, Francisco J; Lucas-Reina, Eva; Romero, Jose M; Valverde, Federico

    2017-06-01

    Measuring day length confers a strong fitness improvement to photosynthetic organisms as it allows them to anticipate light phases and take the best decisions preceding diurnal transitions. In close association with signals from the circadian clock and the photoreceptors, photoperiodic sensing constitutes also a precise way to determine the passing of the seasons and to take annual decisions such as the best time to flower or the beginning of dormancy. Photoperiodic sensing in photosynthetic organisms is ancient and two major stages in its evolution could be identified, the cyanobacterial time sensing and the evolutionary tool kit that arose in green algae and developed into the photoperiodic system of modern plants. The most recent discoveries about the evolution of the perception of light, measurement of day length and relationship with the circadian clock along the evolution of the eukaryotic green lineage will be discussed in this review. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Factors affecting songbird nest survival in riparian forests in a Midwestern agricultural landscape

    Treesearch

    Rebecca G. Peak; Frank R. Thompson; Terry L. Shaffer

    2004-01-01

    We investigated factors affecting nest success of songbirds in riparian forest and buffers in northeastern Missouri. We used an information-theoretic approach to determine support for hypotheses concerning effects of nest-site, habitat-patch, edge, and temporal factors on nest success of songbirds in three narrow (55-95 m) and three wide (400-530 m) riparian forests...

  17. Genetic regulation of sex differences in songbirds and lizards.

    PubMed

    Wade, Juli

    2016-02-19

    Sex differences in the morphology of neural and peripheral structures related to reproduction often parallel the frequency of particular behaviours displayed by males and females. In a variety of model organisms, these sex differences are organized in development by gonadal steroids, which also act in adulthood to modulate behavioural expression and in some cases to generate parallel anatomical changes on a seasonal basis. Data collected from diverse species, however, suggest that changes in hormone availability are not sufficient to explain sex and seasonal differences in structure and function. This paper pulls together some of this literature from songbirds and lizards and considers the information in the broader context of taking a comparative approach to investigating genetic mechanisms associated with behavioural neuroendocrinology. © 2016 The Author(s).

  18. Genetic regulation of sex differences in songbirds and lizards

    PubMed Central

    Wade, Juli

    2016-01-01

    Sex differences in the morphology of neural and peripheral structures related to reproduction often parallel the frequency of particular behaviours displayed by males and females. In a variety of model organisms, these sex differences are organized in development by gonadal steroids, which also act in adulthood to modulate behavioural expression and in some cases to generate parallel anatomical changes on a seasonal basis. Data collected from diverse species, however, suggest that changes in hormone availability are not sufficient to explain sex and seasonal differences in structure and function. This paper pulls together some of this literature from songbirds and lizards and considers the information in the broader context of taking a comparative approach to investigating genetic mechanisms associated with behavioural neuroendocrinology. PMID:26833833

  19. Songbirds use spectral shape, not pitch, for sound pattern recognition

    PubMed Central

    Bregman, Micah R.; Patel, Aniruddh D.; Gentner, Timothy Q.

    2016-01-01

    Humans easily recognize “transposed” musical melodies shifted up or down in log frequency. Surprisingly, songbirds seem to lack this capacity, although they can learn to recognize human melodies and use complex acoustic sequences for communication. Decades of research have led to the widespread belief that songbirds, unlike humans, are strongly biased to use absolute pitch (AP) in melody recognition. This work relies almost exclusively on acoustically simple stimuli that may belie sensitivities to more complex spectral features. Here, we investigate melody recognition in a species of songbird, the European Starling (Sturnus vulgaris), using tone sequences that vary in both pitch and timbre. We find that small manipulations altering either pitch or timbre independently can drive melody recognition to chance, suggesting that both percepts are poor descriptors of the perceptual cues used by birds for this task. Instead we show that melody recognition can generalize even in the absence of pitch, as long as the spectral shapes of the constituent tones are preserved. These results challenge conventional views regarding the use of pitch cues in nonhuman auditory sequence recognition. PMID:26811447

  20. [Analysis of photoperiod-sensitivity genes in Minghui63, an restorer line of indica rice(Oryza sativa L.)].

    PubMed

    Luo, Lin-Guang; Xu, Jun-Feng; Zhai, Hu-Qu; Wan, Jian-Min

    2003-09-01

    Se-1 locus and a recessive inhibitor gene i-Se-1. The DH of the hybrid rice "Shanyou63" is 94.7 in Nanjing, lying between Zhenshan97A's and Minghui63's, but more nearer to late maturity parent Minghui63. It has been not expressed that E1 gene usually prolongs days to heading by about 20 days when coexisting with Se-1u or Se-1n. This is possibly made by that inhibitor genes exist in respective parents, which make DH transgression of "Shanyou63" not appear. This phenomenon indicated that the heading date of indica hybrid rice is resulted from the interaction among the photoperiod-sensitive genes and their inhibitor genes in the sterile and the restorer lines.

  1. Lunar Phase-Dependent Expression of Cryptochrome and a Photoperiodic Mechanism for Lunar Phase-Recognition in a Reef Fish, Goldlined Spinefoot

    PubMed Central

    Fukushiro, Masato; Takeuchi, Takahiro; Takeuchi, Yuki; Hur, Sung-Pyo; Sugama, Nozomi; Takemura, Akihiro; Kubo, Yoko; Okano, Keiko; Okano, Toshiyuki

    2011-01-01

    Lunar cycle-associated physiology has been found in a wide variety of organisms. Recent study has revealed that mRNA levels of Cryptochrome (Cry), one of the circadian clock genes, were significantly higher on a full moon night than on a new moon night in coral, implying the involvement of a photoreception system in the lunar-synchronized spawning. To better establish the generalities surrounding such a mechanism and explore the underlying molecular mechanism, we focused on the relationship between lunar phase, Cry gene expression, and the spawning behavior in a lunar-synchronized spawner, the goldlined spinefoot (Siganus guttatus), and we identified two kinds of Cry genes in this animal. Their mRNA levels showed lunar cycle-dependent expression in the medial part of the brain (mesencephalon and diencephalon) peaking at the first quarter moon. Since this lunar phase coincided with the reproductive phase of the goldlined spinefoot, Cry gene expression was considered a state variable in the lunar phase recognition system. Based on the expression profiles of SgCrys together with the moonlight's pattern of timing and duration during its nightly lunar cycle, we have further speculated on a model of lunar phase recognition for reproductive control in the goldlined spinefoot, which integrates both moonlight and circadian signals in a manner similar to photoperiodic response. PMID:22163321

  2. Perineuronal nets and vocal plasticity in songbirds: A proposed mechanism to explain the difference between closed-ended and open-ended learning.

    PubMed

    Cornez, Gilles; Madison, Farrah N; Van der Linden, Annemie; Cornil, Charlotte; Yoder, Kathleen M; Ball, Gregory F; Balthazart, Jacques

    2017-09-01

    Perineuronal nets (PNN) are aggregations of chondroitin sulfate proteoglycans surrounding the soma and proximal processes of neurons, mostly GABAergic interneurons expressing parvalbumin. They limit the plasticity of their afferent synaptic connections. In zebra finches PNN develop in an experience-dependent manner in the song control nuclei HVC and RA (nucleus robustus arcopallialis) when young birds crystallize their song. Because songbird species that are open-ended learners tend to recapitulate each year the different phases of song learning until their song crystallizes at the beginning of the breeding season, we tested whether seasonal changes in PNN expression would be found in the song control nuclei of a seasonally breeding species such as the European starling. Only minimal changes in PNN densities and total number of cells surrounded by PNN were detected. However, comparison of the density of PNN and of PNN surrounding parvalbumin-positive cells revealed that these structures are far less numerous in starlings that show extensive adult vocal plasticity, including learning of new songs throughout the year, than in the closed-ended learner zebra finches. Canaries that also display some vocal plasticity across season but were never formally shown to learn new songs in adulthood were intermediate in this respect. Together these data suggest that establishment of PNN around parvalbumin-positive neurons in song control nuclei has diverged during evolution to control the different learning capacities observed in songbird species. This differential expression of PNN in different songbird species could represent a key cellular mechanism mediating species variation between closed-ended and open-ended learning strategies. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 975-994, 2017. © 2017 Wiley Periodicals, Inc.

  3. Temperature and photoperiod as environmental cues affect body mass and thermoregulation in Chinese bulbuls, Pycnonotus sinensis.

    PubMed

    Hu, Shi-Nan; Zhu, Ying-Yang; Lin, Lin; Zheng, Wei-Hong; Liu, Jin-Song

    2017-03-01

    Seasonal changes in temperature and photoperiod are important environmental cues used by small birds to adjust their body mass ( M b ) and thermogenesis. However, the relative importance of these cues with respect to seasonal adjustments in M b and thermogenesis is difficult to distinguish. In particular, the effects of temperature and photoperiod on energy metabolism and thermoregulation are not well known in many passerines. To address this problem, we measured the effects of temperature and photoperiod on M b , energy intake, resting metabolic rate (RMR), organ mass and physiological and biochemical markers of metabolic activity in the Chinese bulbul ( Pycnonotus sinensis ). Groups of Chinese bulbuls were acclimated in a laboratory to the following conditions: (1) warm and long photoperiod, (2) warm and short photoperiod, (3) cold and long photoperiod, and (4) cold and short photoperiod, for 4 weeks. The results indicate that Chinese bulbuls exhibit adaptive physiological regulation when exposed to different temperatures and photoperiods. M b , RMR, gross energy intake and digestible energy intake were higher in cold-acclimated than in warm-acclimated bulbuls, and in the short photoperiod than in the long photoperiod. The resultant flexibility in energy intake and RMR allows Chinese bulbuls exposed to different temperatures and photoperiods to adjust their energy balance and thermogenesis accordingly. Cold-acclimated birds had heightened state-4 respiration and cytochrome c oxidase activity in their liver and muscle tissue compared with warm-acclimated birds indicating the cellular mechanisms underlying their adaptive thermogenesis. Temperature appears to be a primary cue for adjusting energy budget and thermogenic ability in Chinese bulbuls; photoperiod appears to intensify temperature-induced changes in energy metabolism and thermoregulation. © 2017. Published by The Company of Biologists Ltd.

  4. Striatal FoxP2 Is Actively Regulated during Songbird Sensorimotor Learning

    PubMed Central

    Teramitsu, Ikuko; Poopatanapong, Amy; Torrisi, Salvatore; White, Stephanie A.

    2010-01-01

    Background Mutations in the FOXP2 transcription factor lead to language disorders with developmental onset. Accompanying structural abnormalities in cortico-striatal circuitry indicate that at least a portion of the behavioral phenotype is due to organizational deficits. We previously found parallel FoxP2 expression patterns in human and songbird cortico/pallio-striatal circuits important for learned vocalizations, suggesting that FoxP2's function in birdsong may generalize to speech. Methodology/Principal Findings We used zebra finches to address the question of whether FoxP2 is additionally important in the post-organizational function of these circuits. In both humans and songbirds, vocal learning depends on auditory guidance to achieve and maintain optimal vocal output. We tested whether deafening prior to or during the sensorimotor phase of song learning disrupted FoxP2 expression in song circuitry. As expected, the songs of deafened juveniles were abnormal, however basal FoxP2 levels were unaffected. In contrast, when hearing or deaf juveniles sang for two hours in the morning, FoxP2 was acutely down-regulated in the striatal song nucleus, area X. The extent of down-regulation was similar between hearing and deaf birds. Interestingly, levels of FoxP2 and singing were correlated only in hearing birds. Conclusions/Significance Hearing appears to link FoxP2 levels to the amount of vocal practice. As juvenile birds spent more time practicing than did adults, their FoxP2 levels are likely to be low more often. Behaviorally-driven reductions in the mRNA encoding this transcription factor could ultimately affect downstream molecules that function in vocal exploration, especially during sensorimotor learning. PMID:20062527

  5. Chronic photoperiod disruption does not increase vulnerability to focal cerebral ischemia in young normotensive rats.

    PubMed

    Ku Mohd Noor, Ku Mastura; Wyse, Cathy; Roy, Lisa A; Biello, Stephany M; McCabe, Christopher; Dewar, Deborah

    2017-11-01

    Photoperiod disruption, which occurs during shift work, is associated with changes in metabolism or physiology (e.g. hypertension and hyperglycaemia) that have the potential to adversely affect stroke outcome. We sought to investigate if photoperiod disruption affects vulnerability to stroke by determining the impact of photoperiod disruption on infarct size following permanent middle cerebral artery occlusion. Adult male Wistar rats (210-290 g) were housed singly under two different light/dark cycle conditions ( n = 12 each). Controls were maintained on a standard 12:12 light/dark cycle for nine weeks. For rats exposed to photoperiod disruption, every three days for nine weeks, the lights were switched on 6 h earlier than in the previous photoperiod. T 2 -weighted magnetic resonance imaging was performed at 48 h after middle cerebral artery occlusion. Disruption of photoperiod in young healthy rats for nine weeks did not alter key physiological variables that can impact on ischaemic damage, e.g. blood pressure and blood glucose immediately prior to middle cerebral artery occlusion. There was no effect of photoperiod disruption on infarct size after middle cerebral artery occlusion. We conclude that any potentially adverse effect of photoperiod disruption on stroke outcome may require additional factors such as high fat/high sugar diet or pre-existing co-morbidities.

  6. The effect of latitude on photoperiodic control of gonadal maturation, regression and molt in birds.

    PubMed

    Dawson, Alistair

    2013-09-01

    Photoperiod is the major cue used by birds to time breeding seasons and molt. However, the annual cycle in photoperiod changes with latitude. Within species, for temperate and high latitude species, gonadal maturation and breeding start earlier at lower latitudes but regression and molt both occur at similar times at different latitudes. Earlier gonadal maturation can be explained simply by the fact that considerable maturation occurs before the equinox when photoperiod is longer at lower latitudes - genetic differences between populations are not necessary to explain earlier breeding at lower latitudes. Gonadal regression is caused either by absolute photorefractoriness or, in some species with long breeding seasons, relative photorefractoriness. In either case, the timing of regression and molt cannot be explained by absolute prevailing photoperiod or rate of change in photoperiod - birds appear to be using more subtle cues from the pattern of change in photoperiod. However, there may be no difference between absolute and relative photorefractory species in how they utilise the annual cycle in photoperiod to time regression. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Functional magnetic resonance imaging (FMRI) with auditory stimulation in songbirds.

    PubMed

    Van Ruijssevelt, Lisbeth; De Groof, Geert; Van der Kant, Anne; Poirier, Colline; Van Audekerke, Johan; Verhoye, Marleen; Van der Linden, Annemie

    2013-06-03

    The neurobiology of birdsong, as a model for human speech, is a pronounced area of research in behavioral neuroscience. Whereas electrophysiology and molecular approaches allow the investigation of either different stimuli on few neurons, or one stimulus in large parts of the brain, blood oxygenation level dependent (BOLD) functional Magnetic Resonance Imaging (fMRI) allows combining both advantages, i.e. compare the neural activation induced by different stimuli in the entire brain at once. fMRI in songbirds is challenging because of the small size of their brains and because their bones and especially their skull comprise numerous air cavities, inducing important susceptibility artifacts. Gradient-echo (GE) BOLD fMRI has been successfully applied to songbirds (1-5) (for a review, see (6)). These studies focused on the primary and secondary auditory brain areas, which are regions free of susceptibility artifacts. However, because processes of interest may occur beyond these regions, whole brain BOLD fMRI is required using an MRI sequence less susceptible to these artifacts. This can be achieved by using spin-echo (SE) BOLD fMRI (7,8) . In this article, we describe how to use this technique in zebra finches (Taeniopygia guttata), which are small songbirds with a bodyweight of 15-25 g extensively studied in behavioral neurosciences of birdsong. The main topic of fMRI studies on songbirds is song perception and song learning. The auditory nature of the stimuli combined with the weak BOLD sensitivity of SE (compared to GE) based fMRI sequences makes the implementation of this technique very challenging.

  8. Sexual dimorphism in striatal dopaminergic responses promotes monogamy in social songbirds.

    PubMed

    Tokarev, Kirill; Hyland Bruno, Julia; Ljubičić, Iva; Kothari, Paresh J; Helekar, Santosh A; Tchernichovski, Ofer; Voss, Henning U

    2017-08-11

    In many songbird species, males sing to attract females and repel rivals. How can gregarious, non-territorial songbirds such as zebra finches, where females have access to numerous males, sustain monogamy? We found that the dopaminergic reward circuitry of zebra finches can simultaneously promote social cohesion and breeding boundaries. Surprisingly, in unmated males but not in females, striatal dopamine neurotransmission was elevated after hearing songs. Behaviorally too, unmated males but not females persistently exchanged mild punishments in return for songs. Song reinforcement diminished when dopamine receptors were blocked. In females, we observed song reinforcement exclusively to the mate's song, although their striatal dopamine neurotransmission was only slightly elevated. These findings suggest that song-triggered dopaminergic activation serves a dual function in social songbirds: as low-threshold social reinforcement in males and as ultra-selective sexual reinforcement in females. Co-evolution of sexually dimorphic reinforcement systems can explain the coexistence of gregariousness and monogamy.

  9. Sexual dimorphism in striatal dopaminergic responses promotes monogamy in social songbirds

    PubMed Central

    Hyland Bruno, Julia; Ljubičić, Iva; Kothari, Paresh J; Helekar, Santosh A; Tchernichovski, Ofer; Voss, Henning U

    2017-01-01

    In many songbird species, males sing to attract females and repel rivals. How can gregarious, non-territorial songbirds such as zebra finches, where females have access to numerous males, sustain monogamy? We found that the dopaminergic reward circuitry of zebra finches can simultaneously promote social cohesion and breeding boundaries. Surprisingly, in unmated males but not in females, striatal dopamine neurotransmission was elevated after hearing songs. Behaviorally too, unmated males but not females persistently exchanged mild punishments in return for songs. Song reinforcement diminished when dopamine receptors were blocked. In females, we observed song reinforcement exclusively to the mate’s song, although their striatal dopamine neurotransmission was only slightly elevated. These findings suggest that song-triggered dopaminergic activation serves a dual function in social songbirds: as low-threshold social reinforcement in males and as ultra-selective sexual reinforcement in females. Co-evolution of sexually dimorphic reinforcement systems can explain the coexistence of gregariousness and monogamy. PMID:28826502

  10. Redefining reproductive success in songbirds: Moving beyond the nest success paradigm

    USGS Publications Warehouse

    Streby, Henry M.; Refsnider, Jeanine M.; Andersen, David E.

    2014-01-01

    One of the most commonly estimated parameters in studies of songbird ecology is reproductive success, as a measure of either individual fitness or population productivity. Traditionally, the “success” in reproductive success refers to whether, or how many, nestlings leave nests. Here, we advocate that “reproductive success” in songbirds be redefined as full-season productivity, or the number of young raised to independence from adult care in a breeding season. A growing body of evidence demonstrates interdependence between nest success and fledgling survival, and emphasizes that data from either life stage alone can produce misleading measures of individual fitness and population productivity. Nest success, therefore, is an insufficient measure of reproductive success, and songbird ecology needs to progress beyond this long-standing paradigm. Full-season productivity, an evolutionarily rational measure of reproductive success, provides the framework for appropriately addressing unresolved questions about the adaptive significance of many breeding behaviors and within which effective breeding-grounds conservation and management can be designed.

  11. Songbirds as sentinels of mercury in terrestrial habitats of eastern North America

    USGS Publications Warehouse

    Jackson, Allyson K.; Evers, David C.; Adams, Evan M.; Cristol, Daniel A.; Eagles-Smith, Collin A.; Edmonds, Samuel T.; Gray, Carrie E.; Hoskins, Bart; Lane, Oksana P.; Sauer, Amy; Tear, Timothy

    2015-01-01

    Mercury (Hg) is a globally distributed environmental contaminant with a variety of deleterious effects in fish, wildlife, and humans. Breeding songbirds may be useful sentinels for Hg across diverse habitats because they can be effectively sampled, have well-defined and small territories, and can integrate pollutant exposure over time and space. We analyzed blood total Hg concentrations from 8,446 individuals of 102 species of songbirds, sampled on their breeding territories across 161 sites in eastern North America [geometric mean Hg concentration = 0.25 μg/g wet weight (ww), range <0.01–14.60 μg/g ww]. Our records span an important time period—the decade leading up to implementation of the USEPA Mercury and Air Toxics Standards, which will reduce Hg emissions from coal-fired power plants by over 90 %. Mixed-effects modeling indicated that habitat, foraging guild, and age were important predictors of blood Hg concentrations across species and sites. Blood Hg concentrations in adult invertebrate-eating songbirds were consistently higher in wetland habitats (freshwater or estuarine) than upland forests. Generally, adults exhibited higher blood Hg concentrations than juveniles within each habitat type. We used model results to examine species-specific differences in blood Hg concentrations during this time period, identifying potential Hg sentinels in each region and habitat type. Our results present the most comprehensive assessment of blood Hg concentrations in eastern songbirds to date, and thereby provide a valuable framework for designing and evaluating risk assessment schemes using sentinel songbird species in the time after implementation of the new atmospheric Hg standards.

  12. Migrating songbirds recalibrate their magnetic compass daily from twilight cues.

    PubMed

    Cochran, William W; Mouritsen, Henrik; Wikelski, Martin

    2004-04-16

    Night migratory songbirds can use stars, sun, geomagnetic field, and polarized light for orientation when tested in captivity. We studied the interaction of magnetic, stellar, and twilight orientation cues in free-flying songbirds. We exposed Catharus thrushes to eastward-turned magnetic fields during the twilight period before takeoff and then followed them for up to 1100 kilometers. Instead of heading north, experimental birds flew westward. On subsequent nights, the same individuals migrated northward again. We suggest that birds orient with a magnetic compass calibrated daily from twilight cues. This could explain how birds cross the magnetic equator and deal with declination.

  13. Ontogeny of the daily profile of plasma melatonin in European starlings raised under long or short photoperiods.

    PubMed

    Dawson, Alistair; Van't, Hof Thomas J

    2002-06-01

    Photoperiodic manipulation of young European starlings suggests that their reproductive physiology is incapable of responding to a short photoperiod until they are fully grown. This study aimed to determine whether the lack of response to a short photoperiod is reflected in the daily profile of plasma melatonin concentrations. Five-day-old starlings taken from nest boxes showed a significant (p < 0.0001) rhythm in plasma melatonin concentrations, with high values during night. In nestlings hand-reared from 5 days of age on a long photoperiod (LD 16:8), equivalent to natural photoperiod at the time, the amplitude of the daily rhythm in melatonin increased significantly (p < 0.01) with age until birds were fully grown (20 days old). In nestlings reared on a short photoperiod (LD 8:16), the daily melatonin profile remained almost identical to that of long photoperiod birds until they were fully grown. However, after 20 days old, the duration of elevated nighttime melatonin began to extend to encompass the entire period of darkness. In contrast, fully grown starlings transferred from a long to a short photoperiod had partially adapted to the short photoperiod after 5 days; by 10 days, the daily melatonin profile was identical to that of birds held chronically on a short photoperiod. Thus, consistent with responses of reproductive physiology, the pineal of young birds appears to be incapable of perceiving, or adapting to, a short photoperiod.

  14. [The genetic determination and function of RR-proteins--the regulators of photoperiodic reaction and circadian rhythms in plants].

    PubMed

    Tots'kyĭ, V M; D'iachenko, L F; Muterko, O F; Balashova, I A; Toptikov, V A

    2012-01-01

    The present review devoted to the analysis of recent literature on genetic determination and the domain organization of the newly discovered two-component signaling systems in pro- and eukaryotes. These structures are involved in the regulation of numerous morphological and physiological processes in plants. RR-proteins, it the key elements of signaling systems, they launch a cascade of phosphotransferase reactions and directly or indirectly regulate the transcription and activity other proteins, including enzymes, in response to hormones or environmental factors. Modern views on the molecular and genetic mechanisms of photoperiodic response, circadian rhythms and anti-stress responses in plants are set out in these positions. The relationship between gene expression and photoreceptor sensitivity of plants to photoperiod traced. We present our own data obtained on the isogenic lines of wheat, where been showed dependence expression of structural genes of enzymes on the allelic composition of individual PRR-loci and the duration action of low temperature.

  15. Differences in Number of Midbrain Dopamine Neurons Associated with Summer and Winter Photoperiods in Humans

    PubMed Central

    Aumann, Tim D.; Raabus, Mai; Tomas, Doris; Prijanto, Agustinus; Churilov, Leonid; Spitzer, Nicholas C.; Horne, Malcolm K.

    2016-01-01

    Recent evidence indicates the number of dopaminergic neurons in the adult rodent hypothalamus and midbrain is regulated by environmental cues, including photoperiod, and that this occurs via up- or down-regulation of expression of genes and proteins that are important for dopamine (DA) synthesis in extant neurons (‘DA neurotransmitter switching’). If the same occurs in humans, it may have implications for neurological symptoms associated with DA imbalances. Here we tested whether there are differences in the number of tyrosine hydroxylase (TH, the rate-limiting enzyme in DA synthesis) and DA transporter (DAT) immunoreactive neurons in the midbrain of people who died in summer (long-day photoperiod, n = 5) versus winter (short-day photoperiod, n = 5). TH and DAT immunoreactivity in neurons and their processes was qualitatively higher in summer compared with winter. The density of TH immunopositive (TH+) neurons was significantly (~6-fold) higher whereas the density of TH immunonegative (TH-) neurons was significantly (~2.5-fold) lower in summer compared with winter. The density of total neurons (TH+ and TH- combined) was not different. The density of DAT+ neurons was ~2-fold higher whereas the density of DAT- neurons was ~2-fold lower in summer compared with winter, although these differences were not statistically significant. In contrast, midbrain nuclear volume, the density of supposed glia (small TH- cells), and the amount of TUNEL staining were the same in summer compared with winter. This study provides the first evidence of an association between environmental stimuli (photoperiod) and the number of midbrain DA neurons in humans, and suggests DA neurotransmitter switching underlies this association. PMID:27428306

  16. Short photoperiod increases energy intake, metabolic thermogenesis and organ mass in silky starlings Sturnus sericeus

    PubMed Central

    WANG, Jia-Qi; WANG, Jia-Jia; WU, Xu-Jian; ZHENG, Wei-Hong; LIU, Jin-Song

    2016-01-01

    Environmental cues play important roles in the regulation of an animal’s physiology and behavior. One such cue, photoperiod, plays an important role in the seasonal acclimatization of birds. It has been demonstrated that an animal’s body mass, basal metabolic rate (BMR), and energy intake, are all affected by photoperiod. The present study was designed to examine photoperiod induced changes in the body mass, metabolism and metabolic organs of the silky starling, Sturnus sericeus. Captive silky starlings increased their body mass and BMR during four weeks of acclimation to a short photoperiod. Birds acclimated to a short photoperiod also increased the mass of certain organs (liver, gizzard and small intestine), and both gross energy intake (GEI) and digestible energy intake (DEI), relative to those acclimated to a long photoperiod. Furthermore, BMR was positively correlated with body mass, liver mass, GEI and DEI. These results suggest that silky starlings increase metabolic thermogenesis when exposed to a short photoperiod by increasing their body and metabolic organ mass, and their GEI and DEI. These findings support the hypothesis that bird species from temperate climates typically display high phenotypic flexibility in thermogenic capacity. PMID:27029864

  17. Widespread dispersal of Borrelia burgdorferi-infected ticks collected from songbirds across Canada.

    PubMed

    Scott, John D; Anderson, John F; Durden, Lance A

    2012-02-01

    Millions of Lyme disease vector ticks are dispersed annually by songbirds across Canada, but often overlooked as the source of infection. For clarity on vector distribution, we sampled 481 ticks (12 species and 3 undetermined ticks) from 211 songbirds (42 species/subspecies) nationwide. Using PCR, 52 (29.5%) of 176 Ixodes ticks tested were positive for the Lyme disease spirochete, Borrelia burgdorferi s.l. Immature blacklegged ticks, Ixodes scapularis , collected from infested songbirds had a B. burgdorferi infection prevalence of 36% (larvae, 48%; nymphs, 31%). Notably, Ixodes affinis is reported in Canada for the first time and, similarly, Ixodes auritulus for the initial time in the Yukon. Firsts for bird-parasitizing ticks include I. scapularis in Quebec and Saskatchewan. We provide the first records of 3 tick species cofeeding on passerines (song sparrow, Swainson's thrush). New host records reveal I. scapularis on the blackpoll warbler and Nashville warbler. We furnish the following first Canadian reports of B. burgdorferi-positive ticks: I. scapularis on chipping sparrow, house wren, indigo bunting; I. auritulus on Bewick's wren; and I. spinipalpis on a Bewick's wren and song sparrow. First records of B. burgdorferi-infected ticks on songbirds include the following: the rabbit-associated tick, Ixodes dentatus, in western Canada; I. scapularis in Quebec, Saskatchewan, northern New Brunswick, northern Ontario; and Ixodes spinipalpis (collected in British Columbia). The presence of B. burgdorferi in Ixodes larvae suggests reservoir competency in 9 passerines (Bewick's wren, common yellowthroat, dark-eyed junco, Oregon junco, red-winged blackbird, song sparrow, Swainson's thrush, swamp sparrow, and white-throated sparrow). We report transstadial transmission (larva to nymph) of B. burgdorferi in I. auritulus. Data suggest a possible 4-tick, i.e., I. angustus, I. auritulus, I. pacificus, and I. spinipalpis, enzootic cycle of B. burgdorferi on Vancouver Island

  18. Transoceanic migration by a 12 g songbird.

    PubMed

    DeLuca, William V; Woodworth, Bradley K; Rimmer, Christopher C; Marra, Peter P; Taylor, Philip D; McFarland, Kent P; Mackenzie, Stuart A; Norris, D Ryan

    2015-04-01

    Many fundamental aspects of migration remain a mystery, largely due to our inability to follow small animals over vast spatial areas. For more than 50 years, it has been hypothesized that, during autumn migration, blackpoll warblers (Setophaga striata) depart northeastern North America and undertake a non-stop flight over the Atlantic Ocean to either the Greater Antilles or the northeastern coast of South America. Using miniaturized light-level geolocators, we provide the first irrefutable evidence that the blackpoll warbler, a 12 g boreal forest songbird, completes an autumn transoceanic migration ranging from 2270 to 2770 km (mean ± s.d.: 2540 ± 257) and requiring up to 3 days (62 h ± 10) of non-stop flight. This is one of the longest non-stop overwater flights recorded for a songbird and confirms what has long been believed to be one of the most extraordinary migratory feats on the planet. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  19. Focal expression of mutant huntingtin in the songbird basal ganglia disrupts cortico-basal ganglia networks and vocal sequences

    PubMed Central

    Tanaka, Masashi; Singh Alvarado, Jonnathan; Murugan, Malavika; Mooney, Richard

    2016-01-01

    The basal ganglia (BG) promote complex sequential movements by helping to select elementary motor gestures appropriate to a given behavioral context. Indeed, Huntington’s disease (HD), which causes striatal atrophy in the BG, is characterized by hyperkinesia and chorea. How striatal cell loss alters activity in the BG and downstream motor cortical regions to cause these disorganized movements remains unknown. Here, we show that expressing the genetic mutation that causes HD in a song-related region of the songbird BG destabilizes syllable sequences and increases overall vocal activity, but leave the structure of individual syllables intact. These behavioral changes are paralleled by the selective loss of striatal neurons and reduction of inhibitory synapses on pallidal neurons that serve as the BG output. Chronic recordings in singing birds revealed disrupted temporal patterns of activity in pallidal neurons and downstream cortical neurons. Moreover, reversible inactivation of the cortical neurons rescued the disorganized vocal sequences in transfected birds. These findings shed light on a key role of temporal patterns of cortico-BG activity in the regulation of complex motor sequences and show how a genetic mutation alters cortico-BG networks to cause disorganized movements. PMID:26951661

  20. Translating birdsong: songbirds as a model for basic and applied medical research.

    PubMed

    Brainard, Michael S; Doupe, Allison J

    2013-07-08

    Songbirds, long of interest to basic neuroscience, have great potential as a model system for translational neuroscience. Songbirds learn their complex vocal behavior in a manner that exemplifies general processes of perceptual and motor skill learning and, more specifically, resembles human speech learning. Song is subserved by circuitry that is specialized for vocal learning and production but that has strong similarities to mammalian brain pathways. The combination of highly quantifiable behavior and discrete neural substrates facilitates understanding links between brain and behavior, both in normal states and in disease. Here we highlight (a) behavioral and mechanistic parallels between birdsong and aspects of speech and social communication, including insights into mirror neurons, the function of auditory feedback, and genes underlying social communication disorders, and (b) contributions of songbirds to understanding cortical-basal ganglia circuit function and dysfunction, including the possibility of harnessing adult neurogenesis for brain repair.

  1. Translating Birdsong: Songbirds as a model for basic and applied medical research

    PubMed Central

    2014-01-01

    Songbirds, long of interest to basic neuroscientists, have great potential as a model system for translational neuroscience. Songbirds learn their complex vocal behavior in a manner that exemplifies general processes of perceptual and motor skill learning, and more specifically resembles human speech learning. Song is subserved by circuitry that is specialized for vocal learning and production, but that has strong similarities to mammalian brain pathways. The combination of a highly quantifiable behavior and discrete neural substrates facilitates understanding links between brain and behavior, both normally and in disease. Here we highlight 1) behavioral and mechanistic parallels between birdsong and aspects of speech and social communication, including insights into mirror neurons, the function of auditory feedback, and genes underlying social communication disorders, and 2) contributions of songbirds to understanding cortical-basal ganglia circuit function and dysfunction, including the possibility of harnessing adult neurogenesis for brain repair. PMID:23750515

  2. A New Mechanism of Sound Generation in Songbirds

    NASA Astrophysics Data System (ADS)

    Goller, Franz; Larsen, Ole N.

    1997-12-01

    Our current understanding of the sound-generating mechanism in the songbird vocal organ, the syrinx, is based on indirect evidence and theoretical treatments. The classical avian model of sound production postulates that the medial tympaniform membranes (MTM) are the principal sound generators. We tested the role of the MTM in sound generation and studied the songbird syrinx more directly by filming it endoscopically. After we surgically incapacitated the MTM as a vibratory source, zebra finches and cardinals were not only able to vocalize, but sang nearly normal song. This result shows clearly that the MTM are not the principal sound source. The endoscopic images of the intact songbird syrinx during spontaneous and brain stimulation-induced vocalizations illustrate the dynamics of syringeal reconfiguration before phonation and suggest a different model for sound production. Phonation is initiated by rostrad movement and stretching of the syrinx. At the same time, the syrinx is closed through movement of two soft tissue masses, the medial and lateral labia, into the bronchial lumen. Sound production always is accompanied by vibratory motions of both labia, indicating that these vibrations may be the sound source. However, because of the low temporal resolution of the imaging system, the frequency and phase of labial vibrations could not be assessed in relation to that of the generated sound. Nevertheless, in contrast to the previous model, these observations show that both labia contribute to aperture control and strongly suggest that they play an important role as principal sound generators.

  3. Flying with the winds: differential migration strategies in relation to winds in moth and songbirds.

    PubMed

    Åkesson, Susanne

    2016-01-01

    The gamma Y moth selects to migrate in stronger winds compared to songbirds, enabling fast transport to distant breeding sites, but a lower precision in orientation as the moth allows itself to be drifted by the winds. Photo: Ian Woiwod. In Focus: Chapman, J.R., Nilsson, C., Lim, K.S., Bäckman, J., Reynolds, D.R. & Alerstam, T. (2015) Adaptive strategies in nocturnally migrating insects and songbirds: contrasting responses to winds. Journal of Animal Ecology, In press Insects and songbirds regularly migrate long distances across continents and seas. During these nocturnal migrations, they are exposed to a fluid medium, the air, in which they transport themselves by flight at similar speeds as the winds may carry them. It is crucial for an animal to select the most favourable flight conditions relative to winds to minimize the distance flown on a given amount of fuel and to avoid hazardous situations. Chapman et al. (2015a) showed contrasting strategies in how moths initiate migration predominantly under tailwind conditions, allowing themselves to drift to a larger extent and gain ground speed as compared to nocturnal songbird migrants. The songbirds use more variable flight strategies in relation to winds, where they sometimes allow themselves to drift, and at other occasions compensate for wind drift. This study shows how insects and birds have differentially adapted to migration in relation to winds, which is strongly dependent on their own flight capability, with higher flexibility enabling fine-tuned responses to keep a time programme and reach a goal in songbirds compared to in insects. © 2015 The Author. Journal of Animal Ecology © 2015 British Ecological Society.

  4. Variations in the photoperiodic cloacal response of Japanese quail: association with testes weight and feather color

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Oishi, T.; Konishi, T.

    1983-04-01

    The size of the cloacal gland was found to be a reliable indicator of testicular activity of Japanese quail. Six experiments were performed to examine the effects of alternating long and short photoperiod on the size of the cloacal gland of male Japanese quail. Three types of photoperiodic cloacal responses were distinguished. Type I birds became refractory to short photoperiods after they had experienced 5 weeks or more of short days. They maintained large cloacal glands under subsequent condition of alternating long and short photoperiod. Type II birds were intermediate types I and III birds did not become refractory tomore » short photoperiods after experiencing 5 weeks or more of short days. The cloacal glands responded to conditions of alternating long and short photoperiods with increases or decreases in size. Feather color on the throat was found to correspond to the type of cloacal response. Type I birds had brick-red throat feathers. Type II birds had white feathers intermingled with brick-red feathers. Type III had white throat feathers. The percentages of types I, II, and III observed in the experimental population was 67, 18, and 15%, respectively. Type III birds were used to study the effects of blinding on the cloacal response to short photoperiod. Five out of eight blinded type III birds did not lose the responsiveness to short photoperiod. These results are consistent with the view that extraocular photoreceptors participate in the photoperiodic gonadal response of Japanese quail.« less

  5. Discussion of Yellow Starthistle Response to Irradiance, Photoperiod, and CO2

    NASA Technical Reports Server (NTRS)

    Bubenheim, David L.

    2016-01-01

    Yellow Starthistle (Centaurea solstitialis) is a native annual weed of Eurasia and since introduction into the US has become an invasive and noxious weed. It grows in a rosette habit during the vegetative state and usually bolts in summer to produce a large and branched flowering stem. Time to flowering in Yellow Starthistle has been attributed to photoperiod, nitrogen nutrition, temperature, and water stress. We executed a series of studies to investigate the role of light, both photoperiod and photosynthetic photon flux, on flowering and development in Yellow Starthistle. Treatments were presented in 4 ways: (1) Varying day length with constant photosynthetic photon flus (PPF) - providing increasing daily integrated Photosynthetic Photon (PP) exposure with longer day lengths, (2) Varying day length while adjusting PPF to maintain daily PP exposure for all treatments, (3) Extending photoperiod treatments beyond common 12-h photosynthetic period with low light levels to maintain both PPF and daily PP across all treatments; and (4) Reciprocal exchange of plant among photoperiod treatments. Yellow Starthistle appears to be a long-day plant with a critical day length requirement between 14-h and 16-h to induce transition from vegetative to floral stages in development. PPF and daily absorbed photons did not affect time to vegetative / floral stage transition, but did affect factors such as biomass accumulation and canopy parameters such as specific leaf mass. Reciprocal exchange of plants between floral inducing and inhibiting photoperiod treatments, starting at 2-weeks post germination, had no effect on to flower. Flowering was determined by photoperiod experienced during the first 2-weeks (or less) post germination. Yellow Starthistle net photosynthetic response to elevated atmospheric CO2 concentrations over a range of photosynthetically active radiation flux rates and temperatures will also be presented and discussed.

  6. Environmental variability and acoustic signals: a multi-level approach in songbirds.

    PubMed

    Medina, Iliana; Francis, Clinton D

    2012-12-23

    Among songbirds, growing evidence suggests that acoustic adaptation of song traits occurs in response to habitat features. Despite extensive study, most research supporting acoustic adaptation has only considered acoustic traits averaged for species or populations, overlooking intraindividual variation of song traits, which may facilitate effective communication in heterogeneous and variable environments. Fewer studies have explicitly incorporated sexual selection, which, if strong, may favour variation across environments. Here, we evaluate the prevalence of acoustic adaptation among 44 species of songbirds by determining how environmental variability and sexual selection intensity are associated with song variability (intraindividual and intraspecific) and short-term song complexity. We show that variability in precipitation can explain short-term song complexity among taxonomically diverse songbirds, and that precipitation seasonality and the intensity of sexual selection are related to intraindividual song variation. Our results link song complexity to environmental variability, something previously found for mockingbirds (Family Mimidae). Perhaps more importantly, our results illustrate that individual variation in song traits may be shaped by both environmental variability and strength of sexual selection.

  7. Conservation of the photoperiodic neuroendocrine axis among vertebrates: evidence from the teleost fish, Gasterosteus aculeatus

    PubMed Central

    O’Brien, Conor S.; Bourdo, Ryan; Bradshaw, William E.; Holzapfel, Christina M.; Cresko, William. A.

    2012-01-01

    Photoperiod, or length of day, has a predictable annual cycle, making it an important cue for the timing of seasonal behavior and development in many organisms. Photoperiod is widely used among temperate and polar animals to regulate the timing of sexual maturation. The proper sensing and interpretation of photoperiod can be tightly tied to an organism’s overall fitness. In photoperiodic mammals and birds the thyroid hormone pathway initiates sexual maturation, but the degree to which this pathway is conserved across other vertebrates is not well known. We use the threespine stickleback Gasterosteus aculeatus, as a representative teleost to quantify the photoperiodic response of key genes in the thyroid hormone pathway under controlled laboratory conditions. We find that the photoperiodic responses of the hormones are largely consistent amongst multiple populations, although differences suggest physiological adaptation to various climates. We conclude that the thyroid hormone pathway initiates sexual maturation in response to photoperiod in G. aculeatus, and our results show that more components of this pathway are conserved among mammals, birds, and teleost fish than was previously known. However, additional endocrinology, cell biology and molecular research will be required to define precisely which aspects of the pathway are conserved across vertebrates. PMID:22504272

  8. Conservation of the photoperiodic neuroendocrine axis among vertebrates: evidence from the teleost fish, Gasterosteus aculeatus.

    PubMed

    O'Brien, Conor S; Bourdo, Ryan; Bradshaw, William E; Holzapfel, Christina M; Cresko, William A

    2012-08-01

    Photoperiod, or length of day, has a predictable annual cycle, making it an important cue for the timing of seasonal behavior and development in many organisms. Photoperiod is widely used among temperate and polar animals to regulate the timing of sexual maturation. The proper sensing and interpretation of photoperiod can be tightly tied to an organism's overall fitness. In photoperiodic mammals and birds the thyroid hormone pathway initiates sexual maturation, but the degree to which this pathway is conserved across other vertebrates is not well known. We use the threespine stickleback Gasterosteus aculeatus, as a representative teleost to quantify the photoperiodic response of key genes in the thyroid hormone pathway under controlled laboratory conditions. We find that the photoperiodic responses of the hormones are largely consistent amongst multiple populations, although differences suggest physiological adaptation to various climates. We conclude that the thyroid hormone pathway initiates sexual maturation in response to photoperiod in G. aculeatus, and our results show that more components of this pathway are conserved among mammals, birds, and teleost fish than was previously known. However, additional endocrinology, cell biology and molecular research will be required to define precisely which aspects of the pathway are conserved across vertebrates. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Utilization of potatoes for life support systems. II - The effects of temperature under 24-h and 12-h photoperiods

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; Steffen, Kenneth L.; Tibbitts, Theodore W.; Palta, Jiwan P.

    1986-01-01

    The effects of temperature and the photoperiod length on the growth and tuberization of Norland potatoes were investigated for two photoperiods, 12-h and 24-hr at 400 micromol/sq m per sec PPF, and at temperatures of 12, 16, 20, 24, and 28 C. It was found that stem length increased with increasing temperature under both photoperiods. The highest tuber yield was obtained at 16 C under the 24-hr photoperiod and at 20 C under the 12-hr photoperiod (i.e., increasing the photoperiod from 12 to 24 hrs effectively decreases the optimal temperature for tuber formation). Little or no tuber formation occurred at 28 C under either photoperiod.

  10. The pea GIGAS gene is a FLOWERING LOCUS T homolog necessary for graft-transmissible specification of flowering but not for responsiveness to photoperiod.

    PubMed

    Hecht, Valérie; Laurie, Rebecca E; Vander Schoor, Jacqueline K; Ridge, Stephen; Knowles, Claire L; Liew, Lim Chee; Sussmilch, Frances C; Murfet, Ian C; Macknight, Richard C; Weller, James L

    2011-01-01

    Garden pea (Pisum sativum) was prominent in early studies investigating the genetic control of flowering and the role of mobile flowering signals. In view of recent evidence that genes in the FLOWERING LOCUS T (FT) family play an important role in generating mobile flowering signals, we isolated the FT gene family in pea and examined the regulation and function of its members. Comparison with Medicago truncatula and soybean (Glycine max) provides evidence of three ancient subclades (FTa, FTb, and FTc) likely to be common to most crop and model legumes. Pea FT genes show distinctly different expression patterns with respect to developmental timing, tissue specificity, and response to photoperiod and differ in their activity in transgenic Arabidopsis thaliana, suggesting they may have different functions. We show that the pea FTa1 gene corresponds to the GIGAS locus, which is essential for flowering under long-day conditions and promotes flowering under short-day conditions but is not required for photoperiod responsiveness. Grafting, expression, and double mutant analyses show that GIGAS/FTa1 regulates a mobile flowering stimulus but also provide clear evidence for a second mobile flowering stimulus that is correlated with expression of FTb2 in leaf tissue. These results suggest that induction of flowering by photoperiod in pea results from interactions among several members of a diversified FT family.

  11. Neurosteroid production in the songbird brain: a re-evaluation of core principles

    PubMed Central

    London, Sarah E.; Remage-Healey, Luke; Schlinger, Barney A.

    2009-01-01

    Concepts of brain-steroid signaling have traditionally placed emphasis on the gonads and adrenals as the source of steroids, the strict dichotomy of early developmental (“organizational”) and mature (“activational”) effects, and a relatively slow mechanism of signaling through intranuclear receptors. Continuing research shows that these concepts are not inaccurate, but they are certainly incomplete. In this review, we focus on the song control circuit of songbird species to demonstrate how each of these concepts is limited. We discuss the solid evidence for steroid synthesis within the brain (“neurosteroidogenesis”), the role of neurosteroids in organizational events that occur both early in development and later in life, and how neurosteroids can act in acute and non-traditional ways. The songbird model therefore illustrates how neurosteroids can dramatically increase the diversity of steroid-sensitive brain functions in a behaviorally-relevant system. We hope this inspires further research and thought into neurosteroid signaling in songbirds and other animals. PMID:19442685

  12. Identifying yield-optimizing environments for two cowpea breeding lines by manipulating photoperiod and harvest scenario

    NASA Technical Reports Server (NTRS)

    Ohler, T. A.; Mitchell, C. A.

    1996-01-01

    Photoperiod and harvest scenario of cowpea (Vigna unguiculata L. Walp) canopies were manipulated to optimize productivity for use in future controlled ecological life-support systems. Productivity was measured by edible yield rate (EYR:g m-2 day-1), shoot harvest index (SHI: g edible biomass [g total shoot dry weight]), and yield-efficiency rate (YER:g edible biomass m-2 day-1 per[g nonedible shoot dry weight]). Breeding lines 'IT84S-2246' (S-2246) and "IT82D-889' (D-889) were grown in a greenhouse under 8-, 12-, or 24-h photoperiods. S-2246 was short-day and D-889 was day-neutral for flowering. Under each photoperiod, cowpeas were harvested either for leaves only, seeds only, or leaves plus seeds (mixed harvest). Photoperiod did not affect EYR of either breeding line for any harvest scenario tested. Averaged over both breeding lines, seed harvest gave the highest EYR at 6.7 g m-2 day-1. The highest SHI (65%) and YER (94 mg m-2 day-1 g-1) were achieved for leaf-only harvest of D-889 under an 8-h photoperiod. For leaf-only harvest of S-2246, both SHI and YER increased with increasing photoperiod, but declined for seed-only and mixed harvests. However, photoperiod had no effect on SHI or YER for D-889 for any harvest scenario. A second experiment utilized the short-day cowpea breeding line 'IT89KD-288' (D-288) and the day-neutral breeding line 'IT87D-941-1' (D-941) to compare yield parameters using photoperiod extension under differing lamp types. This experiment confirmed the photoperiod responses of D-889 and S-2246 to a mixed-harvest scenario and indicated that daylength extension with higher irradiance from high pressure sodium lamps further suppressed EYR, SHI, and YER of the short-day breeding line D-288.

  13. Long photoperiods sustain high pH in Arctic kelp forests.

    PubMed

    Krause-Jensen, Dorte; Marbà, Núria; Sanz-Martin, Marina; Hendriks, Iris E; Thyrring, Jakob; Carstensen, Jacob; Sejr, Mikael Kristian; Duarte, Carlos M

    2016-12-01

    Concern on the impacts of ocean acidification on calcifiers, such as bivalves, sea urchins, and foraminifers, has led to efforts to understand the controls on pH in their habitats, which include kelp forests and seagrass meadows. The metabolism of these habitats can lead to diel fluctuation in pH with increases during the day and declines at night, suggesting no net effect on pH at time scales longer than daily. We examined the capacity of subarctic and Arctic kelps to up-regulate pH in situ and experimentally tested the role of photoperiod in determining the capacity of Arctic macrophytes to up-regulate pH. Field observations at photoperiods of 15 and 24 hours in Greenland combined with experimental manipulations of photoperiod show that photoperiods longer than 21 hours, characteristic of Arctic summers, are conducive to sustained up-regulation of pH by kelp photosynthesis. We report a gradual increase in pH of 0.15 units and a parallel decline in pCO 2 of 100 parts per million over a 10-day period in an Arctic kelp forest over midsummer, with ample scope for continued pH increase during the months of continuous daylight. Experimental increase in CO 2 concentration further stimulated the capacity of macrophytes to deplete CO 2 and increase pH. We conclude that long photoperiods in Arctic summers support sustained up-regulation of pH in kelp forests, with potential benefits for calcifiers, and propose that this mechanism may increase with the projected expansion of Arctic vegetation in response to warming and loss of sea ice.

  14. Photoperiod shift effects on yield characteristics of rice

    NASA Technical Reports Server (NTRS)

    Volk, G. M.; Mitchell, C. A.

    1995-01-01

    Edible yield must be maximized for each crop species selected for inclusion in the Controlled Ecological Life-Support System (CELSS) proposed by NASA to support long-term manned space missions. In a greenhouse study aimed at increasing biomass partitioning to rice (Oryza sativa L.) grain, plants of the high yielding semi-dwarf rice cultivar Ai-Nan-Tsao were started in pots under 8-h photoperiods at a density of 212 plants m-2. After different periods of time under 8-h photoperiods, pots were switched to continuous light for the remainder of the cropping cycle. Continuous light did not delay time to first panicle emergence (60 d) or time to harvest (83 d). There was a positive correlation between the length of continuous light treatments and nongrain biomass. Grain yield (1.6 +/- 0.2 g plant-1) did not increase in continuous light. Yield-efficiency rate (grain weight per length of cropping cycle, canopy volume, and weight of nongrain shoot biomass) was used to compare treatments. Small Ai-Nan-Tsao rice canopies grown under 8-h photoperiods were more efficient producers of grain than canopies grown under continuous light for a portion of the rice cropping cycle.

  15. Natural Variation and Genetics of Photoperiodism in Wyeomyia smithii.

    PubMed

    Bradshaw, William E; Holzapfel, Christina M

    2017-01-01

    Seasonal change in the temperate and polar regions of Earth determines how the world looks around us and, in fact, how we live our day-to-day lives. For biological organisms, seasonal change typically involves complex physiological and metabolic reorganization, the majority of which is regulated by photoperiodism. Photoperiodism is the ability of animals and plants to use day length or night length, resulting in life-historical transformations, including seasonal development, migration, reproduction, and dormancy. Seasonal timing determines not only survival and reproductive success but also the structure and organization of complex communities and, ultimately, the biomes of Earth. Herein, a small mosquito, Wyeomyia smithii, that lives only in the water-filled leaves of a carnivorous plant over a wide geographic range, is used to explore the genetic and evolutionary basis of photoperiodism. Photoperiodism in W. smithii is considered in the context of its historical biogeography in nature to examine the startling finding that recent rapid climate change can drive genetic change in plants and animals at break-neck speed, and to challenge the ponderous 80+ year search for connections between daily and seasonal time-keeping mechanisms. Finally, a model is proposed that reconciles the seemingly disparate 24-h daily clock driven by the invariant rotation of Earth about its axis with the evolutionarily flexible seasonal timer orchestrated by variable seasonality driven by the rotation of Earth about the Sun. © 2017 Elsevier Inc. All rights reserved.

  16. Memory in the making: localized brain activation related to song learning in young songbirds

    PubMed Central

    Gobes, Sharon M. H.; Zandbergen, Matthijs A.; Bolhuis, Johan J.

    2010-01-01

    Songbird males learn to sing their songs from an adult ‘tutor’ early in life, much like human infants learn to speak. Similar to humans, in the songbird brain there are separate neural substrates for vocal production and for auditory memory. In adult songbirds, the caudal pallium, the avian equivalent of the auditory association cortex, has been proposed to contain the neural substrate of tutor song memory, while the song system is involved in song production as well as sensorimotor learning. If this hypothesis is correct, there should be neuronal activation in the caudal pallium, and not in the song system, while the young bird is hearing the tutor song. We found increased song-induced molecular neuronal activation, measured as the expression of an immediate early gene, in the caudal pallium of juvenile zebra finch males that were in the process of learning to sing their songs. No such activation was found in the song system. Molecular neuronal activation was significantly greater in response to tutor song than to novel song or silence in the medial part of the caudomedial nidopallium (NCM). In the caudomedial mesopallium, there was significantly greater molecular neuronal activation in response to tutor song than to silence. In addition, in the NCM there was a significant positive correlation between spontaneous molecular neuronal activation and the strength of song learning during sleep. These results suggest that the caudal pallium contains the neural substrate for tutor song memory, which is activated during sleep when the young bird is in the process of learning its song. The findings provide insight into the formation of auditory memories that guide vocal production learning, a process fundamental for human speech acquisition. PMID:20534608

  17. Photoperiod Modulates Fast Delayed Rectifier Potassium Currents in the Mammalian Circadian Clock.

    PubMed

    Farajnia, Sahar; Meijer, Johanna H; Michel, Stephan

    2016-10-01

    One feature of the mammalian circadian clock, situated in the suprachiasmatic nucleus (SCN), is its ability to measure day length and thereby contribute to the seasonal adaptation of physiology and behavior. The timing signal from the SCN, namely the 24 hr pattern of electrical activity, is adjusted according to the photoperiod being broader in long days and narrower in short days. Vasoactive intestinal peptide and gamma-aminobutyric acid play a crucial role in intercellular communication within the SCN and contribute to the seasonal changes in phase distribution. However, little is known about the underlying ionic mechanisms of synchronization. The present study was aimed to identify cellular mechanisms involved in seasonal encoding by the SCN. Mice were adapted to long-day (light-dark 16:8) and short-day (light-dark 8:16) photoperiods and membrane properties as well as K + currents activity of SCN neurons were measured using patch-clamp recordings in acute slices. Remarkably, we found evidence for a photoperiodic effect on the fast delayed rectifier K + current, that is, the circadian modulation of this ion channel's activation reversed in long days resulting in 50% higher peak values during the night compared with the unaltered day values. Consistent with fast delayed rectifier enhancement, duration of action potentials during the night was shortened and afterhyperpolarization potentials increased in amplitude and duration. The slow delayed rectifier, transient K + currents, and membrane excitability were not affected by photoperiod. We conclude that photoperiod can change intrinsic ion channel properties of the SCN neurons, which may influence cellular communication and contribute to photoperiodic phase adjustment. © The Author(s) 2016.

  18. Impacts of invasive plants on songbirds: Using song structure as an indicator of habitat quality

    Treesearch

    Yvette Ortega

    2007-01-01

    Invasive species can alter habitat quality over broad scales, so they pose a severe threat to songbird populations. Through our long-term research program supported by BEMRP, we have found that changes in habitat quality induced by exotic plants like spotted knapweed can lead to subtle yet profound changes in songbird populations. For example, in knapweed-invaded...

  19. Effects of melatonin administration on embryo implantation and offspring growth in mice under different schedules of photoperiodic exposure.

    PubMed

    Zhang, Lu; Zhang, Zhenzhen; Wang, Feng; Tian, Xiuzhi; Ji, Pengyun; Liu, Guoshi

    2017-10-02

    Embryo implantation is crucial for animal reproduction. Unsuccessful embryo implantation leads to pregnancy failure, especially in human-assisted conception. Environmental factors have a profound impact on embryo implantation. Because people are being exposed to more light at night, the influence of long-term light exposure on embryo implantation should be explored. The effects of long photoperiodic exposure and melatonin on embryo implantation and offspring growth were examined. Long photoperiodic exposure (18:6 h light:dark) was selected to resemble light pollution. Melatonin (10 -2 , 10 -3 , 10 -4 , 10 -5  M) was added to the drinking water of mice starting at Day 1 (vaginal plugs) until delivery. Melatonin treatment (10 -4 ,10 -5  M) significantly increased litter sizes compared to untreated controls (12.9 ± 0.40 and 12.2 ± 1.01 vs. 11.5 ± 0.43; P < 0.05). The most effective concentration of melatonin (10 -4  M) was selected for further investigation. No remarkable differences were found between melatonin-treated mice and controls in terms of the pups' birth weights, weaning survival rates, and weaning weights. Long photoperiodic exposure significantly reduced the number of implantation sites in treated mice compared to controls (light/dark, 12/12 h), and melatonin rescued this negative effect. Mechanistic studies revealed that melatonin enhanced the serum 17β-estradiol (E 2 ) levels in the pregnant mice and upregulated the expression of the receptors MT1 and MT2 and p53 in uterine tissue. All of these factors may contribute to the beneficial effects of melatonin on embryo implantation in mice. Melatonin treatment was associated with beneficial effects in pregnant mice, especially those subjected to long photoperiodic exposure. This was achieved by enhanced embryo implantation. At the molecular level, melatonin administration probably increases the E 2 level during pregnancy and upregulates p53 expression by activating MT1/2 in the uterus. All

  20. Effect of photoperiod and 6-methoxybenzoxazolinone (6-MBOA) on the reproduction of male Brandt's voles (Lasiopodomys brandtii).

    PubMed

    Dai, Xin; Shi, Jia; Han, Mei; Wang, Ai Qin; Wei, Wan Hong; Yang, Sheng Mei

    2017-05-15

    Plant secondary metabolite 6-methoxybenzoxazolinone (6-MBOA) has been suggested to stimulate animal reproduction. 6-MBOA is detected in Leymus chinensis, a main diet of Brandt's vole (Lasiopodomys brandtii). We have previously reported a stimulatory effect of 6-MBOA on reproduction of male Brandt's voles under a short-day photoperiod. The goal of this study was to investigate the effect of 6-MBOA on reproductive physiology of male Brandt's voles under a long-day photoperiod and examine if 6-MBOA under this photoperiodic regime altered the reproductive status of male Brandt's voles differently than the short-day photoperiod. Under the long-day photoperiod, a high dose of 6-MBOA decreased KiSS-1 mRNA in the arcuate nucleus (ARC), and we also saw a decrease in circulating levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone (T). Steroidogenic acute regulatory protein (StAR) and cytochrome P450 11a1 (CYP11a1) in the testes, and relative testis weight also decreased with 6-MBOA administration. Compared to the short-day photoperiod, animals under the long-day photoperiod exhibited increased body weight as well as all other reproductive parameters. Our results showed that 6-MBOA inhibited the reproduction of male Brandt's vole under a long-day photoperiod, a stark contrast from its stimulatory effects under a short-day photoperiod. The paradoxical effects of 6-MBOA suggest it may act as a partial agonist of melatonin. These results provide insight into the complex interactions between environmental factors such as photoperiod and diet in the control of Brandt's vole reproduction. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Photoperiodism of Male Offspring Production in the Water Flea Daphnia pulex.

    PubMed

    Toyota, Kenji; Sato, Tomomi; Tatarazako, Norihisa; Iguchi, Taisen

    2017-08-01

    Photoperiodism is a biological seasonal timing system utilized to regulate development and reproduction in organisms. The freshwater micro-crustacean Daphnia pulex displays environmental sex determination, the precise physiological mechanisms of which are largely unknown due to the lack of an experimental system to induce female or male offspring production by alterations of the rearing environment. We recently found that D. pulex, WTN6 strain, produces female or male offspring in response to long-day or short-day conditions, respectively. Taking advantage of this system, here we report the photoperiodic response curve for male offspring production, showing 12 hours as natural critical daylength (50% incidence of male-producing mothers), and that male offspring inducibility is highly sensitive to photoperiodic alterations. By using monochromatic light emitting diode (LED) devices, we found that the effective wavelength is red-light (627 nm), which stably induces male offspring production. This suggests that the red-light photoreceptor may be decisive in the primary step of sex determination process in this strain. Our findings provide the first insights into photoperiodism and red-light as key factors in triggering male offspring production in daphnids.

  2. Responses of alloplasmic (cytoplasm=Triticum timopheevii) and euplasmic wheats (Triticum aestivum) to photoperiod and vernalization.

    PubMed

    Ward, R W; Heyne, E G; Paulsen, G M

    1983-07-01

    Studies were conducted to determine the influence of the male sterility-inducing cytoplasm of Triticum timopheevii (Zhuk.) Zhuk. on response of several common winter wheat (T. aestivum L.) nuclear genotypes to photoperiod and vernalization. Comparative studies of cytoplasmic substitution lines provide information on the role of the cytoplasmic genetic mechanism in growth and development. In the case of cytoplasmic male sterility-based hybrid production systems, ubiquity of sterility-inducing cytoplasm in derived hybrids warrants thorough characterization of its influence on plant phenotype. Factorial combinations of cytoplasm (T. timopheevii and T. aestivum), nuclear genotype, and photoperiod or vernalization treatments were evaluated under hydroponic conditions in controlled environment chambers. Interaction of cytoplasm, photoperiod, and nuclear genotype was significant in one or more experiments for days to anthesis and potential spikelet number, and interaction of cytoplasm, vernalization, and nuclear genotype was significant for days to spike emergence. Long day length was associated with increased percentage seed set in one study, but interactions of photoperiod and cytoplasm were not detected for percentage seed set. Interactions involving cytoplasm and photoperiod or vernalization were interpreted as evidence of the existence of genetic factors in cytoplsam of T. timopheevii which alter photoperiod or vernalization responses of alloplasmic plants relative to responses exhibited by euplasmic plants. Since photoperiod and vernalization responses are critical to adaptation, T. timopheevii cytoplasm can alter adaptability of T. aestivum. The specific effect would be nuclear genotype dependent, and does not appear to be of a magnitude greater than that induced by nuclear genetic variability at loci conditioning photoperiod or vernalization responses or other adaptation-determining characteristics. Normal multilocation/year testing of alloplasmic hybrids should

  3. Using the "Kalanchoe daigremontiana" Plant To Show the Effects of Photoperiodism on Plantlet Formation.

    ERIC Educational Resources Information Center

    Hershey, David R.

    2002-01-01

    Describes an activity demonstrating the importance of photoperiod on plant development. Uses the plant devil's backbone for the experiment and studies the details of photoperiodic requirement for plantlet formation. (Contains 12 references.) (YDS)

  4. Discussion of Yellow Starthistle Response to Photosynthetic Irradiance, Photoperiod, and CO2

    NASA Technical Reports Server (NTRS)

    Bubenheim, David

    2017-01-01

    Yellow Starthistle (Centaurea solstitialis) is a native annual weed of Eurasia and since introduction into the United STates has become an invasive and noxious weed. It grows in a rosette habit during the vegetative state and usually bolts in summer to produce a large and branched flowering stem. Time to flowering in Yellow Starthistle has been attributed to photoperiod, nitrogen nutrition, temperature, and water stress. We executed a series of studies to investigate the role of light, both photoperiod and photosynthetic photon flux, on flowering and development in Yellow Starthistle. Treatments were presented in 4 ways: 1) varying day length with constant photosynthetic photon flus (PPF) providing increasing daily integrated Photosynthetic Photon (PP) exposure with longer day lengths 2) varying day length while adjusting PPF to maintain daily PP exposure for all treatments 3) extending photoperiod treatments beyond common 12-h photosynthetic period with low light levels to maintain both PPF and daily PP across all treatments4)reciprocal exchange of plant among photoperiod treatments Yellow Starthistle appears to be a long-day plant with a critical day length requirement between 14-h and 16-h to induce transition from vegetative to floral stages in development. PPF and daily absorbed photons did not affect time to vegetative floral stage transition, but did affect factors such as biomass accumulation and canopy parameters such as specific leaf mass. Reciprocal exchange of plants between floral inducing and inhibiting photoperiod treatments, starting at 2-weeks post germination, had no effect on to flower. Flowering was determined by photoperiod experienced during the first 2-weeks (or less) post germination.Yellow Starthistle net photosynthetic response to elevated atmospheric CO2 concentrations over a range of photosynthetically active radiation flux rates and temperatures will also be presented and discussed.

  5. Photoperiod constraints on tree phenology, performance and migration in a warming world.

    PubMed

    Way, Danielle A; Montgomery, Rebecca A

    2015-09-01

    Increasing temperatures should facilitate the poleward movement of species distributions through a variety of processes, including increasing the growing season length. However, in temperate and boreal latitudes, temperature is not the only cue used by trees to determine seasonality, as changes in photoperiod provide a more consistent, reliable annual signal of seasonality than temperature. Here, we discuss how day length may limit the ability of tree species to respond to climate warming in situ, focusing on the implications of photoperiodic sensing for extending the growing season and affecting plant phenology and growth, as well as the potential role of photoperiod in controlling carbon uptake and water fluxes in forests. We also review whether there are patterns across plant functional types (based on successional strategy, xylem anatomy and leaf morphology) in their sensitivity to photoperiod that we can use to predict which species or groups might be more successful in migrating as the climate warms, or may be more successfully used for forestry and agriculture through assisted migration schemes. © 2014 John Wiley & Sons Ltd.

  6. Songbird - AN Innovative Uas Combining the Advantages of Fixed Wing and Multi Rotor Uas

    NASA Astrophysics Data System (ADS)

    Thamm, F.-P.; Brieger, N.; Neitzke, K.-P.; Meyer, M.; Jansen, R.; Mönninghof, M.

    2015-08-01

    This paper describes a family of innovative fixed wing UAS with can vertical take off and land - the SONGBIRD family. With nominal payloads starting from 0.5 kg they can take off and land safely like a multi-rotor UAV, removing the need for an airstrip for the critical phases of operation. A specially designed flight controller allows stable flight at every point of the transition phase between VTOL and fixed wing mode. Because of this smooth process with a all time stable flight, very expensive payload like hyperspectral sensors or advanced optical cameras can be used. Due to their design all airplanes of the SONGBIRD family have excellent horizontal flight properties, a maximum speed of over 110 km/h, good gliding properties and long flight times of up to 1 h. Missions were flown in wind speeds up to 18 m/s. At every time of the flight it is possible to interrupt the mission and hover over a point of interest for detail investigations. The complete flight, including take-off and landing can be performed by autopilot. Designed for daily use in professional environments, SONGBIRDs are built out of glass-fibre and carbon composites for a long service life. For safe operations comprehensive security features are implemented, for example redundant flight controllers and sensors, advanced power management system and mature fail safe procedures. The aircraft can be dismantled into small parts for transportation. SONGBIRDS are available for different pay loads, from 500 g to 2 kg. The SONGBIRD family are interesting tools combining the advantages of multi-copter and fixed wing UAS.

  7. Short, natural, and extended photoperiod response in BC2F4 lines of bread wheat with different photoperiod-1 (Ppd-1) alleles.

    PubMed

    Bentley, A R; Horsnell, R; Werner, C P; Turner, A S; Rose, G A; Bedard, C; Howell, P; Wilhelm, E P; Mackay, I J; Howells, R M; Greenland, A; Laurie, D A; Gosman, N

    2013-04-01

    Flowering is a critical period in the life cycle of flowering plant species, resulting in an irreversible commitment of significant resources. Wheat is photoperiod sensitive, flowering only when daylength surpasses a critical length; however, photoperiod insensitivity (PI) has been selected by plant breeders for >40 years to enhance yield in certain environments. Control of flowering time has been greatly facilitated by the development of molecular markers for the Photoperiod-1 (Ppd-1) homeoloci, on the group 2 chromosomes. In the current study, an allelic series of BC2F4 lines in the winter wheat cultivars 'Robigus' and 'Alchemy' was developed to elucidate the influence on flowering of eight gene variants from the B- and D-genomes of bread wheat and the A-genome of durum wheat. Allele effects were tested in short, natural, and extended photoperiods in the field and controlled environments. Across genetic background and treatment, the D-genome PI allele, Ppd-D1a, had a more potent effect on reducing flowering time than Ppd-B1a. However, there was significant donor allele effect for both Ppd-D1a and Ppd-B1a, suggesting the presence of linked modifier genes and/or additional sources of latent sensitivity. Development of Ppd-A1a BC2F4 lines derived from synthetic hexaploid wheat provided an opportunity to compare directly the flowering time effect of the A-genome allele from durum with the B- and D-genome variants from bread wheat for the first time. Analyses indicated that the reducing effect of Ppd-A1a is comparable with that of Ppd-D1a, confirming it as a useful alternative source of PI.

  8. Research update: Yield and nutritive value of photoperiod-sensitive sorghum and sorghum-sudangrass

    USDA-ARS?s Scientific Manuscript database

    The objective of this study was to evaluate the yield of photoperiod-sensitive forage sorghum and sorghum-sudangrass against non-photoperiod-sensitive sorghum, sorghum-sudangrass, or corn silage. Forages were planted on two dates at two locations (Marshfield and Hancock, WI). Results suggested some ...

  9. Morphological response of songbirds to 100 years of landscape change in North America.

    PubMed

    Desrochers, A

    2010-06-01

    Major landscape changes caused by humans may create strong selection pressures and induce rapid evolution in natural populations. In the last 100 years, eastern North America has experienced extensive clear-cutting in boreal areas, while afforestation has occurred in most temperate areas. Based on museum specimens, I show that wings of several boreal forest songbirds and temperate songbirds of non-forest habitats have become more pointed over the last 100 years. In contrast, wings of most temperate forest and early-successional boreal forests species have become less pointed over the same period. In contrast to wing shape, the bill length of most species did not change significantly through time. These results are consistent with the "habitat isolation hypothesis", i.e., songbirds evolved in response to recent changes in the amount of available habitat and associated implications for mobility. Rapid morphological evolution may mitigate, without necessarily preventing, negative consequences of habitat loss caused by humans through direct exploitation or climate change.

  10. ZCN8 encodes a potential orthologue of Arabidopsis FT florigen that integrates both endogenous and photoperiod flowering signals in maize

    PubMed Central

    Lazakis, Chloë M.; Coneva, Viktoriya; Colasanti, Joseph

    2011-01-01

    Higher plants use multiple perceptive measures to coordinate flowering time with environmental and endogenous cues. Physiological studies show that florigen is a mobile factor that transmits floral inductive signals from the leaf to the shoot apex. Arabidopsis FT protein is widely regarded as the archetype florigen found in diverse plant species, particularly in plants that use inductive photoperiods to flower. Recently, a large family of FT homologues in maize, the Zea CENTRORADIALIS (ZCN) genes, was described, suggesting that maize also contains FT-related proteins that act as a florigen. The product of one member of this large family, ZCN8, has several attributes that make it a good candidate as a maize florigen. Mechanisms underlying the floral transition in maize are less well understood than those of other species, partly because flowering in temperate maize is dependent largely on endogenous signals. The maize indeterminate1 (id1) gene is an important regulator of maize autonomous flowering that acts in leaves to mediate the transmission or production of florigenic signals. This study finds that id1 acts upstream of ZCN8 to control its expression, suggesting a possible new link to flowering in day-neutral maize. Moreover, in teosinte, a tropical progenitor of maize that requires short-day photoperiods to induce flowering, ZCN8 is highly up-regulated in leaves under inductive photoperiods. Finally, vascular-specific expression of ZCN8 in Arabidopsis complements the ft-1 mutation, demonstrating that leaf-specific expression of ZCN8 can induce flowering. These results suggest that ZCN8 may encode a florigen that integrates both endogenous and environmental signals in maize. PMID:21730358

  11. Analysis of Photoperiod Requirements of Soft Winter Wheat from the Eastern United States

    USDA-ARS?s Scientific Manuscript database

    Photoperiod response plays a major role in determining the climatic adaptation of wheat, and variation is commonly associated with Ppd loci on group two chromosomes. Seventy-three soft winter wheat (SWW) cultivars from the eastern U.S. were tested for photoperiod response in growth chambers. Floweri...

  12. Effects of photoperiod and food restriction on the reproductive physiology of female California mice

    PubMed Central

    Steinman, Michael Q.; Knight, Jennifer A.; Trainor, Brian C.

    2012-01-01

    Many temperate-zone animals use changes in photoperiod to time breeding. Shorter term cues, like food availability, are integrated with photoperiod to adjust reproductive timing under unexpected conditions. Many mice of the genus Peromyscus breed in the summer. California mice (Peromyscus californicus), however, can breed year round, but tend to begin breeding in the winter. Glial cells may be involved in transduction of environmental signals that regulate gonadotrophin releasing hormone (GnRH) activity. We examined the effects of diet and photoperiod on reproduction in female California mice. Mice placed on either short days (8L:16D) or long days (16L:8D) were food restricted (80% of normal intake) or fed ad libitum. Short day-food restricted mice showed significant regression of the reproductive system. GnRH-immunoreactivity was increased in the tuberal hypothalamus of long day-food restricted mice. This may be associated with the sparing effect long days have when mice are food restricted. The number of GFAP-immunoreactive fibers in proximity to GnRH nerve terminals correlated negatively with uterine size in ad libitum but not food restricted mice, suggesting diet may alter glial regulation of the reproductive axis. There was a trend towards food restriction increasing uterine expression of c-fos mRNA, an estrogen dependent gene. Similar to other seasonally breeding rodents, short days render the reproductive system of female California mice more susceptible to effects of food restriction. This may be vestigial, or it may have evolved to mitigate consequences of unexpectedly poor winter food supplies. PMID:22245263

  13. Carbon dioxide effects on potato growth under different photoperiods and irradiance

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; Tibbitts, Theodore W.; Fitzpatrick, Ann H.

    1991-01-01

    The effects of atmospheric CO2 concentration, photosynthetic photon flux (PPF), and the length of the photoperiod on the tuber yield were investigated for three potato cultivars (Norland, Russet Burbank, and Denali), by growing these cultivars for 90 days in atmospheres containing 350 or 1000 micromol/mol CO2, at photoperiods of 12- or 24-hr, and at PPFs of 400 or 800 micromol/sq m per sec. Air temperatures and relative humidity were kept at 16 C and 70 percent, respectively. It was found that the tuber yield of Denali potatoes showed the greatest increase (21 percent) in response to increased CO2 across all irradiance treatments, while the tuber yields of Russet and Norland were increased 18 and 9 percent, respectively. Greater plant growth from CO2 enrichment was observed under lower PPF and the shorter (12 hr) photoperiod.

  14. Autumn photosynthetic decline and growth cessation in seedlings of white spruce are decoupled under warming and photoperiod manipulations.

    PubMed

    Stinziano, Joseph R; Way, Danielle A

    2017-08-01

    Climate warming is expected to increase the seasonal duration of photosynthetic carbon fixation and tree growth in high-latitude forests. However, photoperiod, a crucial cue for seasonality, will remain constant, which may constrain tree responses to warming. We investigated the effects of temperature and photoperiod on weekly changes in photosynthetic capacity, leaf biochemistry and growth in seedlings of a boreal evergreen conifer, white spruce [Picea glauca (Moench) Voss]. Warming delayed autumn declines in photosynthetic capacity, extending the period when seedlings had high carbon uptake. While photoperiod was correlated with photosynthetic capacity, short photoperiods did not constrain the maintenance of high photosynthetic capacity under warming. Rubisco concentration dynamics were affected by temperature but not photoperiod, while leaf pigment concentrations were unaffected by treatments. Respiration rates at 25 °C were stimulated by photoperiod, although respiration at the growth temperatures was increased in warming treatments. Seedling growth was stimulated by increased photoperiod and suppressed by warming. We demonstrate that temperature is a stronger control on the seasonal timing of photosynthetic down-regulation than is photoperiod. Thus, while warming can stimulate carbon uptake in boreal conifers, the extra carbon may be directed towards respiration rather than biomass, potentially limiting carbon sequestration under climate change. © 2017 John Wiley & Sons Ltd.

  15. Anthropogenic noise decreases urban songbird diversity and may contribute to homogenization.

    PubMed

    Proppe, Darren S; Sturdy, Christopher B; St Clair, Colleen Cassady

    2013-04-01

    More humans reside in urban areas than at any other time in history. Protected urban green spaces and transportation greenbelts support many species, but diversity in these areas is generally lower than in undeveloped landscapes. Habitat degradation and fragmentation contribute to lowered diversity and urban homogenization, but less is known about the role of anthropogenic noise. Songbirds are especially vulnerable to anthropogenic noise because they rely on acoustic signals for communication. Recent studies suggest that anthropogenic noise reduces the density and reproductive success of some bird species, but that species which vocalize at frequencies above those of anthropogenic noise are more likely to inhabit noisy areas. We hypothesize that anthropogenic noise is contributing to declines in urban diversity by reducing the abundance of select species in noisy areas, and that species with low-frequency songs are those most likely to be affected. To examine this relationship, we calculated the noise-associated change in overall species richness and in abundance for seven common songbird species. After accounting for variance due to vegetative differences, species richness and the abundance of three of seven species were reduced in noisier locations. Acoustic analysis revealed that minimum song frequency was highly predictive of a species' response to noise, with lower minimum song frequencies incurring greater noise-associated reduction in abundance. These results suggest that anthropogenic noise affects some species independently of vegetative conditions, exacerbating the exclusion of some songbird species in otherwise suitable habitat. Minimum song frequency may provide a useful metric to predict how particular species will be affected by noise. In sum, mitigation of noise may enhance habitat suitability for many songbird species, especially for species with songs that include low-frequency elements. © 2012 Blackwell Publishing Ltd.

  16. Internode and petiole elongation of soybean in response to photoperiod and end-of-day light quality

    NASA Technical Reports Server (NTRS)

    Thomas, J. F.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1985-01-01

    Elongation of main stem internodes and petioles of soybeans, Glycine max 'Ransom,' was examined in response to various photoperiod/temperature combinations and to end-of-day (EOD) light quality. Photoperiod treatments consisted of 10, 14, and 16 h in combination with day/night temperatures of 18/14, 22/18, 26/22, 30/26, and 34/30 C. The EOD treatments consisted of exposing plants to illumination from either incandescent (high far-red component, FR) or fluorescent (high red component, R) lamps during the final 0.5 h of a 10-h photoperiod. Internode elongation was not significantly promoted by the photoperiod treatments, and, in fact, under the two highest temperature regimes, internode elongation was suppressed under the longer photoperiods. Petiole elongation, however, was enhanced under the longer photoperiods at all temperatures. In the EOD light study, internode and petiole elongation was significantly greater on plants exposed to 0.5 h EOD from incandescent lamps than from fluorescent. Under the incandescent EOD treatment, plants increased dry matter production by 41% and exhibited greater partitioning of assimilates in stem and root portions than under fluorescent EOD.

  17. Lead exposure and poisoning of songbirds using the Coeur d'Alene River Basin, Idaho

    USGS Publications Warehouse

    Hansen, James A.; Audet, Daniel; Spears, Brian L.; Healy, Kate A.; Brazzle, Roy E.; Hoffman, David J.; Dailey, Anne; Beyer, W. Nelson

    2011-01-01

    Previous studies have found widespread Pb poisoning of waterfowl in the Coeur d'Alene River Basin in northern Idaho, USA, which has been contaminated by mining and smelting activities. We studied the exposure of ground-feeding songbirds to Pb, sampling 204 American robins (Turdus migratorius), song sparrows (Melospiza melodia), and Swainson's thrushes (Catharus ustulatus) throughout the basin. These songbirds had mean blood Pb concentrations (mg/kg, dry weight) of less than 0.19 at a reference area (25 mg Pb/kg soil), 1.09 at moderately contaminated sites (170 to 1300 mg Pb/kg soil), and 2.06 at highly contaminated sites (2000 to 5000 mg Pb/kg soil). Based on guidelines for evaluating blood Pb in birds, 6% of robins from the highly contaminated sites had background concentrations, 24% were subclinically poisoned, 52% were clinically poisoned, and 18% were severely clinically poisoned with Pb. Blood Pb concentrations were lower in song sparrows than in robins and lowest in Swainson's thrushes. More than half of the robins and song sparrows from all contaminated sites and more than half of the Swainson's thrushes from highly contaminated sites showed at least 50% inhibition of the activity of the enzyme δ-aminolevulinic acid dehydratase (ALAD), commonly used as a measure of exposure to Pb. The highest hepatic Pb concentration of 61 mg/kg (dry weight) was detected in a song sparrow. Using Al as a marker for soil in songbird ingesta, we estimated average soil ingestion rates as 20% in robins, 17% in song sparrows, and 0.7% in Swainson's thrushes. Soil Pb in ingesta accounted for almost all of the songbirds' exposure to Pb. Based on these results, it is recommended that ecological risk assessments of ground-feeding songbirds at contaminated sites include soil ingestion as a pathway of exposure to Pb.

  18. SONGBIRD COMMUNITIES INDICATE ECOLOGICAL CONDITION OF THE CENTRAL APPALACHIANS

    EPA Science Inventory

    During the spring breeding season, more than a hundred songbird species conduct a birds-eye assessment of the Mid-Atlantic highlands to determine suitable habitat for mating and raising young. Different bird species require different habitats for food, shelter and breeding. Some ...

  19. Conjunction of Vocal Production and Perception Regulates Expression of the Immediate Early Gene ZENK in a Novel Cortical Region of Songbirds

    PubMed Central

    Alderete, Tanya L.; Chang, Daniel

    2010-01-01

    The cortical nucleus LMAN (lateral magnocellular nucleus of the anterior nidopallium) provides the output of a basal ganglia pathway that is necessary for acquisition of learned vocal behavior during development in songbirds. LMAN is composed of two subregions, a core and a surrounding shell, that give rise to independent pathways that traverse the forebrain in parallel. The LMANshell pathway forms a recurrent loop that includes a cortical region, the dorsal region of the caudolateral nidopallium (dNCL), hitherto unknown to be involved with learned vocal behavior. Here we show that vocal production strongly induces the IEG product ZENK in dNCL of zebra finches. Hearing tutor song while singing is more effective at inducing expression in dNCL of juvenile birds during the auditory–motor integration stage of vocal learning than is hearing conspecific song. In contrast, hearing conspecific song is relatively more effective at inducing expression in adult birds, regardless of whether they are producing song. Furthermore, ZENK+ neurons in dNCL include projection neurons that are part of the LMANshell recurrent loop and a high proportion of dNCL projection neurons express ZENK in singing juvenile birds that hear tutor song. Thus juvenile birds that are actively refining their vocal pattern to imitate a tutor song show high levels of ZENK induction in dNCL neurons when they are singing while hearing the song of their tutor and low levels when they hear a novel conspecific. This pattern indicates that dNCL is a novel brain region involved with vocal learning and that its function is developmentally regulated. PMID:20107119

  20. Effects of Photoperiod and Temperature on Growth and Development in Clouded Salamander (Hynobius nebulosus) Larvae.

    PubMed

    Kukita, Sayuri; Gouda, Mika; Ikeda, Sakiko; Ishibashi, Sakiko; Furuya, Tatsunori; Nakamura, Keiji

    2015-06-01

    Day length is one of the most important factors that organisms use to predict seasonal changes in their environment. Several amphibians regulate their growth and development in response to photoperiod. However, many studies have not focused on the ecological effects of the photoperiodic response on growth and development because they use tropical animals, animals from a commercial source or from unknown localities, or extreme light regimens for experiments. In the present study, we examined the effects of photoperiod on growth and development in the clouded salamander (Hynobius nebulosus) by raising larvae under different photoperiods and at different temperatures in the laboratory. The average larval period under a long-day photoperiod of L16:D8 was longer than that under L12:D12 at 15°C or 20°C, although the difference between the photoperiods was only significant for 15°C. Juveniles weighed more at metamorphosis under L16:D8 than those under L12:D12, irrespective of temperature, suggesting that a longer developmental period results in a heavier body weight. The head width of juveniles did not differ for different photoperiods at either temperature. However, the growth rate of the head width under L12:D12 was faster than that under L16:D8 at 15°C. Long day length appears to produce larger H. nebulosus juveniles in a relatively stable aquatic environment with a low population density. Thus, development may be accelerated when the day length becomes shorter as winter approaches, and larvae may have increased the growth rate of their head widths to compensate for the shorter growing period under shorter day lengths.

  1. Epigenomic and functional analyses reveal roles of epialleles in the loss of photoperiod sensitivity during domestication of allotetraploid cottons.

    PubMed

    Song, Qingxin; Zhang, Tianzhen; Stelly, David M; Chen, Z Jeffrey

    2017-05-31

    Polyploidy is a pervasive evolutionary feature of all flowering plants and some animals, leading to genetic and epigenetic changes that affect gene expression and morphology. DNA methylation changes can produce meiotically stable epialleles, which are transmissible through selection and breeding. However, the relationship between DNA methylation and polyploid plant domestication remains elusive. We report comprehensive epigenomic and functional analyses, including ~12 million differentially methylated cytosines in domesticated allotetraploid cottons and their tetraploid and diploid relatives. Methylated genes evolve faster than unmethylated genes; DNA methylation changes between homoeologous loci are associated with homoeolog-expression bias in the allotetraploids. Significantly, methylation changes induced in the interspecific hybrids are largely maintained in the allotetraploids. Among 519 differentially methylated genes identified between wild and cultivated cottons, some contribute to domestication traits, including flowering time and seed dormancy. CONSTANS (CO) and CO-LIKE (COL) genes regulate photoperiodicity in Arabidopsis. COL2 is an epiallele in allotetraploid cottons. COL2A is hypermethylated and silenced, while COL2D is repressed in wild cottons but highly expressed due to methylation loss in all domesticated cottons tested. Inhibiting DNA methylation activates COL2 expression, and repressing COL2 in cultivated cotton delays flowering. We uncover epigenomic signatures of domestication traits during cotton evolution. Demethylation of COL2 increases its expression, inducing photoperiodic flowering, which could have contributed to the suitability of cotton for cultivation worldwide. These resources should facilitate epigenetic engineering, breeding, and improvement of polyploid crops.

  2. Local Populations of Arabidopsis thaliana Show Clear Relationship between Photoperiodic Sensitivity of Flowering Time and Altitude

    PubMed Central

    Lewandowska-Sabat, Anna M.; Fjellheim, Siri; Olsen, Jorunn E.; Rognli, Odd A.

    2017-01-01

    Adaptation of plants to local conditions that vary substantially within their geographic range is essential for seasonal timing of flowering, a major determinant of plant reproductive success. This study investigates photoperiodic responses in natural populations of Arabidopsis thaliana from high northern latitudes and their significance for local adaptation. Thirty lineages from ten local A. thaliana populations, representing different locations across an altitudinal gradient (2–850 m a.s.l.) in Norway, were grown under uniform controlled conditions, and used to screen for responses to five different photoperiods. We studied relationships between variation in photoperiodic sensitivity of flowering time, altitude, and climatic factors associated with the sites of origin. We found that variation in response to photoperiod is significantly correlated with altitude and climatic variables associated with the sites of origin of the populations. Populations originating from lower altitudes showed stronger photoperiodic sensitivity than populations from higher altitudes. Our results indicate that the altitudinal climatic gradient generates clinal variation in adaptive traits in A. thaliana. PMID:28659966

  3. To Become Senders, Songbirds Must be Receivers First.

    PubMed

    Rodríguez-Saltos, Carlos Antonio

    2017-10-01

    Courtship signals are attractive; in other words, receivers are motivated to approach courtship signals. Though the concept of a receiver is commonly associated in the literature with that of a mate seeker, young songbirds that are learning to sing by imitating conspecifics are also receivers. Juvenile songbirds are attracted to conspecific songs, which has been shown by juveniles working to hear song in operant chambers. The mechanisms explaining this attraction are poorly understood. Here, I review studies that hint at the mechanisms by which conspecific song becomes attractive. In at least some species, juveniles imitate individuals with which they have a strong social bond, such as the father. Such cases suggest that social reward plays a role in the process of song becoming attractive. In addition, experiments using birds reared in isolation from conspecific song have shown that juveniles imitate songs that have acoustic features that are typically found in conspecific song. Those studies suggest that such features are attractive to juveniles regardless of their social experience. The relative contributions of social reward and species-typical acoustic features to the attractiveness of a song can be determined using methods such as operant conditioning. For example, juvenile songbirds can be given control over the playback of songs that differ in a given attribute, such as acoustic similarity to the song of the father. The juveniles will frequently elicit playback of the songs that are attractive to them. Investigating the mechanisms that contribute to the attractiveness of conspecific song to learners will broaden our understanding of the evolution of song as a courtship signal, because the preferences of learners may ultimately determine what will be sung to potential mates. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  4. Migration and the evolution of duetting in songbirds.

    PubMed

    Logue, David M; Hall, Michelle L

    2014-05-07

    Many groups of animals defend shared resources with coordinated signals. The best-studied of these signals are the vocal duets produced by mated pairs of birds. Duets are believed to be more common among tropical-breeding species, but a comprehensive test of this hypothesis is lacking, and the mechanisms that generate latitudinal patterns in duetting are not known. We used a stratified sample of 372 songbird species to conduct the first broad-scale, phylogenetically explicit analysis of duet evolution. We found that duetting evolves in association with the absence of migration, but not with sexual monochromatism or tropical breeding. We conclude that the evolution of migration exerts a major influence on the evolution of duetting. The perceived association between tropical breeding and duetting may be a by-product of the migration-duetting relationship. Migration reduces the average duration of partnerships, potentially reducing the benefits of cooperative behaviour, including duetting. Ultimately, the evolution of coordinated resource-defence signals in songbirds may be driven by ecological conditions that favour sedentary lifestyles and social stability.

  5. Migration and the evolution of duetting in songbirds

    PubMed Central

    Logue, David M.; Hall, Michelle L.

    2014-01-01

    Many groups of animals defend shared resources with coordinated signals. The best-studied of these signals are the vocal duets produced by mated pairs of birds. Duets are believed to be more common among tropical-breeding species, but a comprehensive test of this hypothesis is lacking, and the mechanisms that generate latitudinal patterns in duetting are not known. We used a stratified sample of 372 songbird species to conduct the first broad-scale, phylogenetically explicit analysis of duet evolution. We found that duetting evolves in association with the absence of migration, but not with sexual monochromatism or tropical breeding. We conclude that the evolution of migration exerts a major influence on the evolution of duetting. The perceived association between tropical breeding and duetting may be a by-product of the migration–duetting relationship. Migration reduces the average duration of partnerships, potentially reducing the benefits of cooperative behaviour, including duetting. Ultimately, the evolution of coordinated resource-defence signals in songbirds may be driven by ecological conditions that favour sedentary lifestyles and social stability. PMID:24619447

  6. Mapping QTL Associated with Photoperiod Sensitivity and Assessing the Importance of QTL×Environment Interaction for Flowering Time in Maize

    PubMed Central

    Wang, Cuiling; Chen, Yanhui; Ku, Lixia; Wang, Tiegu; Sun, Zhaohui; Cheng, Fangfang; Wu, Liancheng

    2010-01-01

    Background An understanding of the genetic determinism of photoperiod response of flowering is a prerequisite for the successful exchange of germplasm across different latitudes. In order to contribute to resolve the genetic basis of photoperiod sensitivity in maize, a set of 201 recombinant inbred lines (RIL), derived from a temperate and tropical inbred line cross were evaluated in 5 field trials spread in short- and long-day environments. Methodology/Principal Findings Firstly, QTL analyses for flowering time and photoperiod sensitivity in maize were conducted in individual photoperiod environments separately, and then, the total genetic effect was partitioned into additive effect (A) and additive-by-environment interaction effect (AE) by using a mixed-model-based composite interval mapping (MCIM) method. Conclusions/Significance Seven putative QTL were found associated with DPS thermal time based on the data estimated in individual environments. Nine putative QTL were found associated with DPS thermal time across environments and six of them showed significant QTL×enviroment (QE) interactions. Three QTL for photoperiod sensitivity were identified on chromosome 4, 9 and 10, which had the similar position to QTL for DPS thermal time in the two long-day environment. The major photoperiod sensitive loci qDPS10 responded to both short and long-day photoperiod environments and had opposite effects in different photoperiod environment. The QTL qDPS3, which had the greatest additive effect exclusively in the short-day environment, were photoperiod independent and should be classified in autonomous promotion pathway. PMID:21124912

  7. Male songbirds provide indirect parental care by guarding females during incubation

    USGS Publications Warehouse

    Fedy, B.C.; Martin, T.E.

    2009-01-01

    Across many taxa, guarding of fertile mates is a widespread tactic that enhances paternity assurance. However, guarding of mates can also occur during the nonfertile period, and the fitness benefits of this behavior are unclear. Male songbirds, for example, sometimes guard nonfertile females during foraging recesses from incubation. We hypothesized that guarding postreproductive mates may have important, but unrecognized, benefits by enhancing female foraging efficiency, thereby increasing time spent incubating eggs. We tested the hypothesis in 2 songbird species by examining female behavior during natural and experimentally induced absences of males. Male absence caused increased vigilance in foraging females that decreased their efficiency and resulted in less time spent incubating eggs. Male guarding of nonfertile females can thus provide a previously unrecognized form of indirect parental care.

  8. Mapping-by-Sequencing Identifies HvPHYTOCHROME C as a Candidate Gene for the early maturity 5 Locus Modulating the Circadian Clock and Photoperiodic Flowering in Barley

    PubMed Central

    Pankin, Artem; Campoli, Chiara; Dong, Xue; Kilian, Benjamin; Sharma, Rajiv; Himmelbach, Axel; Saini, Reena; Davis, Seth J; Stein, Nils; Schneeberger, Korbinian; von Korff, Maria

    2014-01-01

    Phytochromes play an important role in light signaling and photoperiodic control of flowering time in plants. Here we propose that the red/far-red light photoreceptor HvPHYTOCHROME C (HvPHYC), carrying a mutation in a conserved region of the GAF domain, is a candidate underlying the early maturity 5 locus in barley (Hordeum vulgare L.). We fine mapped the gene using a mapping-by-sequencing approach applied on the whole-exome capture data from bulked early flowering segregants derived from a backcross of the Bowman(eam5) introgression line. We demonstrate that eam5 disrupts circadian expression of clock genes. Moreover, it interacts with the major photoperiod response gene Ppd-H1 to accelerate flowering under noninductive short days. Our results suggest that HvPHYC participates in transmission of light signals to the circadian clock and thus modulates light-dependent processes such as photoperiodic regulation of flowering. PMID:24996910

  9. Effect of reverse photoperiod on in vitro regeneration and piperine production in Piper nigrum L.

    PubMed

    Ahmad, Nisar; Abbasi, Bilal Haider; Fazal, Hina; Khan, Mubarak Ali; Afridi, Muhammad Siddique

    2014-01-01

    In this study, a novel approach for in vitro regeneration of Piper nigrum L. has been applied in order to increase healthy biomass, phytochemicals and piperine production via reverse photoperiod (16hD/8hL). Leaf portions of the seed-derived plants were placed on an MS-medium fortified with different PGRs. Under 16hD/8hL, thidiazuron (TDZ; 4.0 mg L⁻¹) and BA (1.5 mg L⁻¹) was found to be the most effective (<90%) in callus induction. Two concentrations (1.5, 2.0 mg L⁻¹) of the IBA produced>80% shoots from callus cultures. Healthy shoots were transferred to rooting medium and higher percentage of rooting (<90%) was observed on IBA (1.5 mg L⁻¹). These in vitro tissues were subjected to amino acid analysis, spectrophotometry, and HPLC. ARG, SER, THR, and TYR were the most abundant components out of 17 amino acids. Higher amino acid production was observed under normal photoperiod (16hL/8hD) than under reverse photoperiod (16hD/8hL). The highest total phenolic content (TPC; 9.91 mg/g-DW) and flavonoid content (7.38 mg/g-DW) were observed in callus cultures incubated under 16hL/8hD than other tissues incubated under 16hD/8hL photoperiod. Higher DPPH and PoMo activities were observed in tissues incubated under 16hL/8hD photoperiod, while ABTS and Fe²⁺ chelating activities were found higher in tissues incubated under reverse photoperiod. Significant quantities of piperine content were observed in all tissues except callus cultures. These results suggest that reverse photoperiod is a promising approach for callus induction, phytochemicals and piperine production for commercial applications. Copyright © 2013 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  10. Photoperiodic inhibition of testicular development is mediated by the pineal gland in white-footed mice

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Johnston, P.G.; Boshes, M.; Zucker, I.

    White-footed mice were maintained in short or long photoperiods from birth to 60 days of age (10 h vs. 14 h of light per day). Testes weights and spermatogenesis were substantially reduced in short daylengths. Pinealectomy at 5-7 days of age eliminated the suppressive effect of photoperiod on the reproductive system. However, testicular development was not retarded in intact males kept from 25 to 60 days of age in short daylengths. Exposure to short daylengths prior to 25 days of age contributes to photoperiodic inhibition of testicular development. Removal of the pineal gland did not consistently affect gonadal maturation inmore » long photoperiods. The pineal gland transduces the effects of short daylengths on reproductive development. Some effects of long daylengths on the neuroendocrine axis of white-footed mice may also be mediated by the pineal gland.« less

  11. Twilight and photoperiod affect behavioral entrainment in the house mouse (Mus musculus).

    PubMed

    Comas, M; Hut, R A

    2009-10-01

    The effect of twilight transitions on entrainment of C57BL/6JOlaHsd mice (Mus musculus) was studied using light-dark cycles of different photoperiods (6, 12, and 18 h) and twilight transitions of different durations (0, 1, and 2 h). Phase angle differences of the onset, center of gravity, and offset of activity, activity duration (alpha), as well as free-running period (tau) in continuous darkness were analyzed. The main finding was that for all conditions the onset of activity was close to dusk or lights-off except for the short photoperiod with 2 h of twilight where activity onset was on average 5.3 (SEM 1.07) h after lights-off. This finding contrasts with the results of Boulos and Macchi for Syrian hamsters where a 5.9-h earlier activity onset was observed when similar photoperiod and twilight conditions are compared with a rectangular LD cycle. The authors suggest the opposite effects of 2 h of twilight in the 2 species may be related to their different free-running periods under DD conditions following entrainment to short photoperiod with 2-h twilight conditions. Since the authors observed larger variation in phase angle of entrainment in longer twilight conditions, twilight does not necessarily form a stronger zeitgeber.

  12. Floral Induction in a Photoperiodically Insensitive Duckweed, Lemna paucicostata LP6 1

    PubMed Central

    Khurana, J. P.; Tamot, B. K.; Maheshwari, S. C.

    1988-01-01

    The effects of 20 amino acids and two amides were studied on the flowering of a photoperiodically insensitive duckweed, Lemna paucicostata LP6. Alanine, asparagine, aspartate, cystine, glutamate, glutamine, glycine, lysine, methionine, proline, serine, and threonine induced flowering under a photoperiodic regime of 16 hours light and 8 hours darkness. Among these, glutamate and aspartate were found to be the most effective for flower induction. These acids could initiate flowering even at 5 × 10−7 molar level, though maximal flowering (about 80%) was obtained at 10−5 molar. Change in the photoperiodic schedule or the pH of the nutrient medium did not influence glutamate- or aspartate-induced flowering. The low concentrations at which glutamate and aspartate are effective suggests that they may have a regulatory role rather than simply acting as metabolites. PMID:16666006

  13. Lead exposure and poisoning of songbirds using the Coeur d'Alene River Basin, Idaho, USA.

    PubMed

    Hansen, James A; Audet, Daniel; Spears, Brian L; Healy, Kate A; Brazzle, Roy E; Hoffman, David J; Dailey, Anne; Beyer, W Nelson

    2011-10-01

    Previous studies have found widespread Pb poisoning of waterfowl in the Coeur d'Alene River Basin in northern Idaho, USA, which has been contaminated by mining and smelting activities. We studied the exposure of ground-feeding songbirds to Pb, sampling 204 American robins (Turdus migratorius), song sparrows (Melospiza melodia), and Swainson's thrushes (Catharus ustulatus) throughout the basin. These songbirds had mean blood Pb concentrations (mg/kg, dry weight) of less than 0.19 at a reference area (25 mg Pb/kg soil), 1.09 at moderately contaminated sites (170 to 1300 mg Pb/kg soil), and 2.06 at highly contaminated sites (2000 to 5000 mg Pb/kg soil). Based on guidelines for evaluating blood Pb in birds, 6% of robins from the highly contaminated sites had background concentrations, 24% were subclinically poisoned, 52% were clinically poisoned, and 18% were severely clinically poisoned with Pb. Blood Pb concentrations were lower in song sparrows than in robins and lowest in Swainson's thrushes. More than half of the robins and song sparrows from all contaminated sites and more than half of the Swainson's thrushes from highly contaminated sites showed at least 50% inhibition of the activity of the enzyme δ-aminolevulinic acid dehydratase (ALAD), commonly used as a measure of exposure to Pb. The highest hepatic Pb concentration of 61 mg/kg (dry weight) was detected in a song sparrow. Using Al as a marker for soil in songbird ingesta, we estimated average soil ingestion rates as 20% in robins, 17% in song sparrows, and 0.7% in Swainson's thrushes. Soil Pb in ingesta accounted for almost all of the songbirds' exposure to Pb. Based on these results, it is recommended that ecological risk assessments of ground-feeding songbirds at contaminated sites include soil ingestion as a pathway of exposure to Pb. Copyright © 2011 SETAC.

  14. Photoperiodic Treatments in Morning Glory: A Laboratory Investigation.

    ERIC Educational Resources Information Center

    Madrazo, Gerry M., Jr.; Hounshell, Paul B.

    1978-01-01

    The Japanese morning glory, a short-day plant, is an excellent specimen for studying photoperiodism. This article gives ideas for investigations including the effects of hormones, light quality, and temperature. Preparation of the seed is also discussed. (BB)

  15. Transcriptomic and proteomic analyses of seasonal photoperiodism in the pea aphid

    PubMed Central

    Le Trionnaire, G; Francis, F; Jaubert-Possamai, S; Bonhomme, J; De Pauw, E; Gauthier, J-P; Haubruge, E; Legeai, F; Prunier-Leterme, N; Simon, J-C; Tanguy, S; Tagu, D

    2009-01-01

    Background Aphid adaptation to harsh winter conditions is illustrated by an alternation of their reproductive mode. Aphids detect photoperiod shortening by sensing the length of the night and switch from viviparous parthenogenesis in spring and summer, to oviparous sexual reproduction in autumn. The photoperiodic signal is transduced from the head to the reproductive tract to change the fate of the future oocytes from mitotic diploid embryogenesis to haploid formation of gametes. This process takes place in three consecutive generations due to viviparous parthenogenesis. To understand the molecular basis of the switch in the reproductive mode, transcriptomic and proteomic approaches were used to detect significantly regulated transcripts and polypeptides in the heads of the pea aphid Acyrthosiphon pisum. Results The transcriptomic profiles of the heads of the first generation were slightly affected by photoperiod shortening. This suggests that trans-generation signalling between the grand-mothers and the viviparous embryos they contain is not essential. By analogy, many of the genes and some of the proteins regulated in the heads of the second generation are implicated in visual functions, photoreception and cuticle structure. The modification of the cuticle could be accompanied by a down-regulation of the N-β-alanyldopamine pathway and desclerotization. In Drosophila, modification of the insulin pathway could cause a decrease of juvenile hormones in short-day reared aphids. Conclusion This work led to the construction of hypotheses for photoperiodic regulation of the switch of the reproductive mode in aphids. PMID:19788735

  16. Photoperiod and temperature responses of bud swelling and bud burst in four temperate forest tree species.

    PubMed

    Basler, David; Körner, Christian

    2014-04-01

    Spring phenology of temperate forest trees is optimized to maximize the length of the growing season while minimizing the risk of freezing damage. The release from winter dormancy is environmentally mediated by species-specific responses to temperature and photoperiod. We investigated the response of early spring phenology to temperature and photoperiod at different stages of dormancy release in cuttings from four temperate tree species in controlled environments. By tracking bud development, we were able to identify the onset of bud swelling and bud growth in Acer pseudoplatanus L., Fagus sylvatica L., Quercus petraea (Mattuschka) Liebl. and Picea abies (L.) H. Karst. At a given early stage of dormancy release, the onset and duration of the bud swelling prior to bud burst are driven by concurrent temperature and photoperiod, while the maximum growth rate is temperature dependent only, except for Fagus, where long photoperiods also increased bud growth rates. Similarly, the later bud burst was controlled by temperature and photoperiod (in the photoperiod sensitive species Fagus, Quercus and Picea). We conclude that photoperiod is involved in the release of dormancy during the ecodormancy phase and may influence bud burst in trees that have experienced sufficient chilling. This study explored and documented the early bud swelling period that precedes and defines later phenological stages such as canopy greening in conventional phenological works. It is the early bud growth resumption that needs to be understood in order to arrive at a causal interpretation and modelling of tree phenology at a large scale. Classic spring phenology events mark visible endpoints of a cascade of processes as evidenced here.

  17. Inefficient co-feeding transmission of Borrelia afzelii in two common European songbirds

    PubMed Central

    Heylen, Dieter J. A.; Sprong, Hein; Krawczyk, Aleksandra; Van Houtte, Natalie; Genné, Dolores; Gomez-Chamorro, Andrea; van Oers, Kees; Voordouw, Maarten J.

    2017-01-01

    The spirochete bacterium Borrelia afzelii is the most common cause of Lyme borreliosis in Europe. This tick-borne pathogen can establish systemic infections in rodents but not in birds. However, several field studies have recovered larval Ixodes ricinus ticks infected with B. afzelii from songbirds suggesting successful transmission of B. afzelii. We reviewed the literature to determine which songbird species were the most frequent carriers of B. afzelii-infected I. ricinus larvae and nymphs. We tested experimentally whether B. afzelii is capable of co-feeding transmission on two common European bird species, the blackbird (Turdus merula) and the great tit (Parus major). For each bird species, four naïve individuals were infested with B. afzelii-infected I. ricinus nymphal ticks and pathogen-free larval ticks. None of the co-feeding larvae tested positive for B. afzelii in blackbirds, but a low percentage of infected larvae (3.33%) was observed in great tits. Transstadial transmission of B. afzelii DNA from the engorged nymphs to the adult ticks was observed in both bird species. However, BSK culture found that these spirochetes were not viable. Our study suggests that co-feeding transmission of B. afzelii is not efficient in these two songbird species. PMID:28054584

  18. Convergent evolution of Hawaiian and Australo-Pacific honeyeaters from distant songbird ancestors.

    PubMed

    Fleischer, Robert C; James, Helen F; Olson, Storrs L

    2008-12-23

    The Hawaiian "honeyeaters," five endemic species of recently extinct, nectar-feeding songbirds in the genera Moho and Chaetoptila, looked and acted like Australasian honeyeaters (Meliphagidae), and no taxonomist since their discovery on James Cook's third voyage has classified them as anything else. We obtained DNA sequences from museum specimens of Moho and Chaetoptila collected in Hawaii 115-158 years ago. Phylogenetic analysis of these sequences supports monophyly of the two Hawaiian genera but, surprisingly, reveals that neither taxon is a meliphagid honeyeater, nor even in the same part of the songbird radiation as meliphagids. Instead, the Hawaiian species are divergent members of a passeridan group that includes deceptively dissimilar families of songbirds (Holarctic waxwings, neotropical silky flycatchers, and palm chats). Here we designate them as a new family, the Mohoidae. A nuclear-DNA rate calibration suggests that mohoids diverged from their closest living ancestor 14-17 mya, coincident with the estimated earliest arrival in Hawaii of a bird-pollinated plant lineage. Convergent evolution, the evolution of similar traits in distantly related taxa because of common selective pressures, is illustrated well by nectar-feeding birds, but the morphological, behavioral, and ecological similarity of the mohoids to the Australasian honeyeaters makes them a particularly striking example of the phenomenon.

  19. Effects of shallow natural gas well structures and associated roads on grassland songbird reproductive success in Alberta, Canada.

    PubMed

    Yoo, Jenny; Koper, Nicola

    2017-01-01

    Grassland songbird populations across North America have experienced dramatic population declines due to habitat loss and degradation. In Canada, energy development continues to fragment and disturb prairie habitat, but effects of oil and gas development on reproductive success of songbirds in North American mixed-grass prairies remains largely unknown. From 2010-2012, in southeastern Alberta, Canada, we monitored 257 nests of two ground-nesting grassland songbird species, Savannah sparrow (Passerculus sandwichensis) and chestnut-collared longspur (Calcarius ornatus). Nest locations varied with proximity to and density of conventional shallow gas well structures and associated roads in forty-two 258-ha mixed-grass prairie sites. We estimated the probabilities of nest success and clutch size relative to gas well structures and roads. There was little effect of distance to or density of gas well structure on nest success; however, Savannah sparrow experienced lower nest success near roads. Clutch sizes were lower near gas well structures and cattle water sources. Minimizing habitat disturbance surrounding gas well structures, and reducing abundance of roads and trails, would help minimize impacts on reproductive success for some grassland songbirds.

  20. Effect of photoperiod change on chronobiology of cercarial emergence of Schistosoma japonicum derived from hilly and marshy regions of China.

    PubMed

    Wang, Su-Rong; Zhu, Yuan-Jian; Ge, Qing-Peng; Yang, Meng-Jia; Huang, Ji-Lei; Huang, Wen-Qiao; Zhuge, Hong-Xiang; Lu, Da-Bing

    2015-12-01

    The chronobiology of cercarial emergence appeared to be a genetically controlled behavior, adapted to definitive host species, for schistosome. However, a few physiological and ecological factors, for example the change of photoperiod, were reported to affect the rhythmic emergence of cercariae. Therefore, the effect of photoperiod change on cercarial emergence of two Schistosoma japonicum isolates, the hilly and the marshland, was investigated. Four shedding experiments each under a different photoperiod were conducted. Under a natural photoperiod, two distinct shedding modes, one from the hilly region and one from the marshland, were observed. Under a reversed photoperiod, the regular pattern (i.e. under a natural photoperiod) of S. japonicum cercarial emergence was reversed for the marshland isolate and disappeared for the hilly isolate. With an input of a 2 h darkness from 7am to 9am, the cercarial emergence peak were delayed for the two isolates; whereas with an input of a 2 h darkness from 5pm to 7pm, neither effect on the cercarial emergence rhythm was observed. The total cercariae emerged for both parasite isolates varied with a different photoperiod. The results indicate that the change of photoperiod could affect the chronobiology of S japonicum cercarial emergence. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Chemosignaling diversity in songbirds: chromatographic profiling of preen oil volatiles in different species.

    PubMed

    Soini, Helena A; Whittaker, Danielle J; Wiesler, Donald; Ketterson, Ellen D; Novotny, Milos V

    2013-11-22

    Large foraging seabirds are known to navigate to food sources using their excellent sense of smell, but much less is known about the use of olfaction by the songbirds (passerine birds). Some evidence of individual recognition based on the bird preen oil volatile organic compound (VOC) compositions, which is the main odor source in birds, have been reported for dark-eyed junco and house finch. In this study we have investigated preen oil VOCs in 16 different songbird species and two other small bird species in order to determine whether the VOC compositions follow phylogenetic and evolutionary relatedness. We have used the stir bar sorptive extraction (SBSE) methodology followed by gas chromatography-mass spectrometry (GC-MS) to determine preen oil VOCs during the long light summer conditions for mostly wild caught birds. Large diversity among the VOC compositions was observed, while some compound classes were found in almost all species. The divergent VOC profiles did not follow the phylogenetic family lines among the bird species. This suggests that songbirds may use VOC odors as a mate recognition cue. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Comparative Cytogenetics between Two Important Songbird, Models: The Zebra Finch and the Canary

    PubMed Central

    dos Santos, Michelly da Silva; Kretschmer, Rafael; Frankl-Vilches, Carolina; Bakker, Antje; Gahr, Manfred; O´Brien, Patricia C. M.; Ferguson-Smith, Malcolm A.

    2017-01-01

    Songbird species (order Passeriformes, suborder Oscines) are important models in various experimental fields spanning behavioural genomics to neurobiology. Although the genomes of some songbird species were sequenced recently, the chromosomal organization of these species is mostly unknown. Here we focused on the two most studied songbird species in neuroscience, the zebra finch (Taeniopygia guttata) and the canary (Serinus canaria). In order to clarify these issues and also to integrate chromosome data with their assembled genomes, we used classical and molecular cytogenetics in both zebra finch and canary to define their chromosomal homology, localization of heterochromatic blocks and distribution of rDNA clusters. We confirmed the same diploid number (2n = 80) in both species, as previously reported. FISH experiments confirmed the occurrence of multiple paracentric and pericentric inversions previously found in other species of Passeriformes, providing a cytogenetic signature for this order, and corroborating data from in silico analyses. Additionally, compared to other Passeriformes, we detected differences in the zebra finch karyotype concerning the morphology of some chromosomes, in the distribution of 5S rDNA clusters, and an inversion in chromosome 1. PMID:28129381

  3. Relicts from Tertiary Australasia: undescribed families and subfamilies of songbirds (Passeriformes) and their zoogeographic signal.

    PubMed

    Schodde, Richard; Christidis, Les

    2014-04-14

    A number of hitherto unrecognized, deeply divergent taxa of Australasian songbirds have been revealed by DNA sequence studies in the last decade. Differentiation among them is at levels equivalent to family and subfamily rank among songbirds generally. Accordingly, the purpose of this paper is to name and describe eleven of them formally under Articles 13.1, 13.2, 16.1 and 16.2 of the International Code of Zoological Nomenclature so that they are made available for use in zoology. The taxa are: families Oreoicidae, Eulacestomatidae, Rhagologidae, Ifritidae and Melampittidae, and subfamilies Pachycareinae, Oreoscopinae, Toxorhamphinae, Oedistomatinae, Peltopsinae and Lamproliinae. The families to which the subfamilies belong are documented. Morphological and behavioural traits of the new family-group taxa are discussed; reasons for taxonomic rankings are summarized; and grounds for the geographic origin of corvoid songbirds, to which all the new families belong, are briefly addressed. One new genus,Megalampitta in Melampittidae, is also described.

  4. Functional and evolutionary characterization of the CONSTANS gene family in short-day photoperiodic flowering in soybean.

    PubMed

    Wu, Faqiang; Price, Brian William; Haider, Waseem; Seufferheld, Gabriela; Nelson, Randall; Hanzawa, Yoshie

    2014-01-01

    CONSTANS (CO) plays a central role in photoperiodic flowering control of plants. However, much remains unknown about the function of the CO gene family in soybean and the molecular mechanisms underlying short-day photoperiodic flowering of soybean. We identified 26 CO homologs (GmCOLs) in the soybean genome, many of them previously unreported. Phylogenic analysis classified GmCOLs into three clades conserved among flowering plants. Two homeologous pairs in Clade I, GmCOL1a/GmCOL1b and GmCOL2a/GmCOL2b, showed the highest sequence similarity to Arabidopsis CO. The mRNA abundance of GmCOL1a and GmCOL1b exhibited a strong diurnal rhythm under flowering-inductive short days and peaked at dawn, which coincided with the rise of GmFT5a expression. In contrast, the mRNA abundance of GmCOL2a and GmCOL2b was extremely low. Our transgenic study demonstrated that GmCOL1a, GmCOL1b, GmCOL2a and GmCOL2b fully complemented the late flowering effect of the co-1 mutant in Arabidopsis. Together, these results indicate that GmCOL1a and GmCOL1b are potential inducers of flowering in soybean. Our data also indicate rapid regulatory divergence between GmCOL1a/GmCOL1b and GmCOL2a/GmCOL2b but conservation of their protein function. Dynamic evolution of GmCOL regulatory mechanisms may underlie the evolution of photoperiodic signaling in soybean.

  5. Assessment of risks to ground-feeding songbirds from lead in the Coeur d'Alene Basin, Idaho, USA.

    PubMed

    Sample, Bradley E; Hansen, James A; Dailey, Anne; Duncan, Bruce

    2011-10-01

    Previous assessment of ecological risks within the Coeur d'Alene River Basin identified Pb as a key risk driver for ground-feeding songbirds. Because this conclusion was based almost exclusively on literature data, its strength was determined to range from low to moderate. With the support of the US Environmental Protection Agency (USEPA), the US Fish and Wildlife Service collected site-specific data to address the uncertainty associated with Pb risks to songbirds. These data, plus those from the previous Coeur d'Alene Basin ecological risk assessment, were integrated, and risks to ground-feeding songbirds were reevaluated. These site-specific data were also used to develop updated preliminary remedial goals (PRGs) for Pb in soils that would be protective of songbirds. Available data included site-specific Pb concentrations in blood, liver, and ingesta from 3 songbird species (American robin, song sparrow, and Swainson's thrush), colocated soil data, and soil data from other locations in the basin. Semi-log regression models based on the association between soil Pb and tissue Pb concentrations were applied to measured soil concentrations from the previous risk assessment to estimate Pb exposures in riparian and adjacent upland habitats throughout the Coeur d'Alene Basin. Measured and estimated tissue or dietary exposure was tabulated for 3 areas plus the reference, and then compared to multiple effects measures. As many as 6 exposure-effect metrics were available for assessing risk in any one area. Analyses of site-specific tissue- and diet-based exposure data indicate that exposure of ground-feeding songbirds to Pb in the Coeur d'Alene Basin is sufficient to result in adverse effects. Because this conclusion is based on multiple exposure-effect metrics that include site-specific data, the strength of this conclusion is high. Ecological PRGs were developed by integrating the site-specific regression models with tissue and dietary effect levels to create exposure

  6. Temporal pattern processing in songbirds.

    PubMed

    Comins, Jordan A; Gentner, Timothy Q

    2014-10-01

    Understanding how the brain perceives, organizes and uses patterned information is directly related to the neurobiology of language. Given the present limitations, such knowledge at the scale of neurons, neural circuits and neural populations can only come from non-human models, focusing on shared capacities that are relevant to language processing. Here we review recent advances in the behavioral and neural basis of temporal pattern processing of natural auditory communication signals in songbirds, focusing on European starlings. We suggest a general inhibitory circuit for contextual modulation that can act to control sensory representations based on patterning rules. Copyright © 2014. Published by Elsevier Ltd.

  7. Advantages of comparative studies in songbirds to understand the neural basis of sensorimotor integration.

    PubMed

    Murphy, Karagh; James, Logan S; Sakata, Jon T; Prather, Jonathan F

    2017-08-01

    Sensorimotor integration is the process through which the nervous system creates a link between motor commands and associated sensory feedback. This process allows for the acquisition and refinement of many behaviors, including learned communication behaviors such as speech and birdsong. Consequently, it is important to understand fundamental mechanisms of sensorimotor integration, and comparative analyses of this process can provide vital insight. Songbirds offer a powerful comparative model system to study how the nervous system links motor and sensory information for learning and control. This is because the acquisition, maintenance, and control of birdsong critically depend on sensory feedback. Furthermore, there is an incredible diversity of song organizations across songbird species, ranging from songs with simple, stereotyped sequences to songs with complex sequencing of vocal gestures, as well as a wide diversity of song repertoire sizes. Despite this diversity, the neural circuitry for song learning, control, and maintenance remains highly similar across species. Here, we highlight the utility of songbirds for the analysis of sensorimotor integration and the insights about mechanisms of sensorimotor integration gained by comparing different songbird species. Key conclusions from this comparative analysis are that variation in song sequence complexity seems to covary with the strength of feedback signals in sensorimotor circuits and that sensorimotor circuits contain distinct representations of elements in the vocal repertoire, possibly enabling evolutionary variation in repertoire sizes. We conclude our review by highlighting important areas of research that could benefit from increased comparative focus, with particular emphasis on the integration of new technologies. Copyright © 2017 the American Physiological Society.

  8. Beyond Emotional and Spatial Processes: Cognitive Dysfunction in a Depressive Phenotype Produced by Long Photoperiod Exposure.

    PubMed

    Barnes, Abigail K; Smith, Summer B; Datta, Subimal

    2017-01-01

    Cognitive dysfunction in depression has recently been given more attention and legitimacy as a core symptom of the disorder. However, animal investigations of depression-related cognitive deficits have generally focused on emotional or spatial memory processing. Additionally, the relationship between the cognitive and affective disturbances that are present in depression remains obscure. Interestingly, sleep disruption is one aspect of depression that can be related both to cognition and affect, and may serve as a link between the two. Previous studies have correlated sleep disruption with negative mood and impaired cognition. The present study investigated whether a long photoperiod-induced depressive phenotype showed cognitive deficits, as measured by novel object recognition, and displayed a cognitive vulnerability to an acute period of total sleep deprivation. Adult male Wistar rats were subjected to a long photoperiod (21L:3D) or a normal photoperiod (12L:12D) condition. Our results indicate that our long photoperiod exposed animals showed behaviors in the forced swim test consistent with a depressive phenotype, and showed significant deficits in novel object recognition. Three hours of total sleep deprivation, however, did not significantly change novel object recognition in either group, but the trends suggest that the long photoperiod and normal photoperiod groups had different cognitive responses to total sleep deprivation. Collectively, these results underline the extent of cognitive dysfunction present in depression, and suggest that altered sleep plays a role in generating both the affective and cognitive symptoms of depression.

  9. A circannual clock drives expression of genes central for seasonal reproduction.

    PubMed

    Sáenz de Miera, Cristina; Monecke, Stefanie; Bartzen-Sprauer, Julien; Laran-Chich, Marie-Pierre; Pévet, Paul; Hazlerigg, David G; Simonneaux, Valérie

    2014-07-07

    Animals living in temperate zones anticipate seasonal environmental changes to adapt their biological functions, especially reproduction and metabolism. Two main physiological mechanisms have evolved for this adaptation: intrinsic long-term timing mechanisms with an oscillating period of approximately 1 year, driven by a circannual clock [1], and synchronization of biological rhythms to the sidereal year using day length (photoperiod) [2]. In mammals, the pineal hormone melatonin relays photoperiodic information to the hypothalamus to control seasonal physiology through well-defined mechanisms [3-6]. In contrast, little is known about how the circannual clock drives endogenous changes in seasonal functions. The aim of this study was to determine whether genes involved in photoperiodic time measurement (TSHβ and Dio2) and central control of reproduction (Rfrp and Kiss1) display circannual rhythms in expression under constant conditions. Male European hamsters, deprived of seasonal time cues by pinealectomy and maintenance in constant photoperiod, were selected when expressing a subjective summer or subjective winter state in their circannual cycle of body weight, temperature, and testicular size. TSHβ expression in the pars tuberalis (PT) displayed a robust circannual variation with highest level in the subjective summer state, which was positively correlated with hypothalamic Dio2 and Rfrp expression. The negative sex steroid feedback was found to act specifically on arcuate Kiss1 expression. Our findings reveal TSH as a circannual output of the PT, which in turn regulates hypothalamic neurons controlling reproductive activity. Therefore, both the circannual and the melatonin signals converge on PT TSHβ expression to synchronize seasonal biological activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Photoperiod-dependent modulation of anti-Müllerian hormone in female Siberian hamsters, Phodopus sungorus.

    PubMed

    Kabithe, Esther W; Place, Ned J

    2008-03-01

    Fertility and fecundity decline with advancing age in female mammals, but reproductive aging was decelerated in Siberian hamsters (Phodopus sungorus) raised in a short-day (SD) photoperiod. Litter success was significantly improved in older hamsters when reared in SD and the number of primordial follicles was twice that of females held in long days (LD). Because anti-Müllerian hormone (AMH) appears to inhibit the recruitment of primordial follicles in mice, we sought to determine whether the expression patterns of AMH differ in the ovaries and serum of hamsters raised in SD versus LD. Ovaries of SD female hamsters are characterized by a paucity of follicular development beyond the secondary stage and are endowed with an abundance of large eosinophilic cells, which may derive from granulosa cells of oocyte-depleted follicles. In ovaries from 10-week-old SD hamsters, we found that the so-called 'hypertrophied granulosa cells' were immunoreactive for AMH, as were granulosa cells within healthy-appearing primary and secondary follicles. Conversely, ovaries from age-matched LD animals lack the highly eosinophilic cells present in SD ovaries. Therefore, AMH staining in LD was limited to primary and secondary follicles that are comparable in number to those found in SD ovaries. The substantially greater AMH expression in SD ovaries probably reflects the abundance of hypertrophied granulosa cells in SD ovaries and their relative absence in LD ovaries. The modulation of ovarian AMH by day length is a strong mechanistic candidate for the preservation of primordial follicles in female hamsters raised in a SD photoperiod.

  11. Management implications of cowbird parasitism on neotropical migrant songbirds

    Treesearch

    Scott K. Robinson; Joseph A. Grzybowski; Stephen I. Rothstein; Margaret C. Brittingham; Lisa J. Petit; Frank R. Thompson

    1993-01-01

    Populations of brood parasitic Brown-headed Cowbirds (Molofhrus afer) have increased to the point where they pose a potential threat to populations of many neotropical migrant songbirds. Because cowbirds mostly feed in short grass (e.g., pastures and lawns) or on bare ground (e.g., row crops), they benefit directly from human activities. Cowbirds...

  12. Gene expression changes during short day induced terminal bud formation in Norway spruce.

    PubMed

    Asante, Daniel K A; Yakovlev, Igor A; Fossdal, Carl Gunnar; Holefors, Anna; Opseth, Lars; Olsen, Jorunn E; Junttila, Olavi; Johnsen, Øystein

    2011-02-01

    The molecular basis for terminal bud formation in autumn is not well understood in conifers. By combining suppression subtractive hybridization and monitoring of gene expression by qRT-PCR analysis, we aimed to identify genes involved in photoperiodic control of growth cessation and bud set in Norway spruce. Close to 1400 ESTs were generated and their functional distribution differed between short day (SD-12 h photoperiod) and long day (LD-24 h photoperiod) libraries. Many genes with putative roles in protection against stress appeared differentially regulated under SD and LD, and also differed in transcript levels between 6 and 20 SDs. Of these, PaTFL1(TERMINAL FLOWER LIKE 1) showed strongly increased transcript levels at 6 SDs. PaCCCH(CCCH-TYPE ZINC FINGER) and PaCBF2&3(C-REPEAT BINDING FACTOR 2&3) showed a later response at 20 SDs, with increased and decreased transcript levels, respectively. For rhythmically expressed genes such as CBFs, such differences might represent a phase shift in peak expression, but might also suggest a putative role in response to SD. Multivariate analyses revealed strong differences in gene expression between LD, 6 SD and 20 SD. The robustness of the gene expression patterns was verified in 6 families differing in bud-set timing under natural light with gradually decreasing photoperiod. © 2010 Blackwell Publishing Ltd.

  13. The Response of Honduras Pine to Various Photoperiods

    Treesearch

    J. A. Vozzo; C. B. Briscoe

    1963-01-01

    Height growth of Honduras pine (P. caribaea. v. hondurensis) seedllng'S 18 shown to be significantly influenced by photoperiod. Maximum initial effect was obtained by the longest period tested, 16 hours; but by 7 weeks, greatest growth was obtained by an interrupted 11 (8+3) hours.

  14. Association of Borrelia garinii and B. valaisiana with Songbirds in Slovakia

    PubMed Central

    Hanincová, Klára; Taragelová, Veronika; Koci, Juraj; Schäfer, Stefanie M.; Hails, Rosie; Ullmann, Amy J.; Piesman, Joseph; Labuda, Milan; Kurtenbach, Klaus

    2003-01-01

    In Europe, 6 of the 11 genospecies of Borrelia burgdorferi sensu lato are prevalent in questing Ixodes ricinus ticks. In most parts of Central Europe, B. afzelii, B. garinii, and B. valaisiana are the most frequent species, whereas B. burgdorferi sensu stricto, B. bissettii, and B. lusitaniae are rare. Previously, it has been shown that B. afzelii is associated with European rodents. Therefore, the aim of this study was to identify reservoir hosts of B. garinii and B. valaisiana in Slovakia. Songbirds were captured in a woodland near Bratislava and investigated for engorged ticks. Questing I. ricinus ticks were collected in the same region. Both tick pools were analyzed for spirochete infections by PCR, followed by DNA-DNA hybridization and, for a subsample, by nucleotide sequencing. Three of the 17 captured songbird species were infested with spirochete-infected ticks. Spirochetes in ticks that had fed on birds were genotyped as B. garinii and B. valaisiana, whereas questing ticks were infected with B. afzelii, B. garinii, and B. valaisiana. Furthermore, identical ospA alleles of B. garinii were found in ticks that had fed on the birds and in questing ticks. The data show that songbirds are reservoir hosts of B. garinii and B. valaisiana but not of B. afzelii. This and previous studies confirm that B. burgdorferi sensu lato is host associated and that this bacterial species complex contains different ecotypes. PMID:12732554

  15. Photoperiod as a proximate factor in control of seasonality in the subtropical male Tree Sparrow, Passer montanus

    PubMed Central

    2011-01-01

    Background Most species of birds exhibit well-defined seasonality in their various physiological and behavioral functions like reproduction, molt, bill color etc. such that they occur at the most appropriate time of the year. Day length has been shown to be a major source of temporal information regulating seasonal reproduction and associated events in a number of avian species. The present study aims to investigate the role of photoperiod in control of seasonal cycles in the subtropical male tree sparrow (Passer montanus) and to compare its responses at Shillong (Latitude 25°34'N, Longitude 91°53'E) with those exhibited by its conspecifics and related species at other latitudes. Results Initial experiment involving study of seasonal cycles revealed that the wild tree sparrows posses definite seasonal cycles of testicular volume, molt and bill color. These cycles were found remarkably linked to annual solar cycle suggesting the possibility of their photoperiodic control. To confirm this possibility in the next experiment, the photosensitive birds were exposed to three different light-dark regimes that were close to what they experience at this latitude: 9L/15D (close to shortest day length), 12L/12D (equinox day length) and 14L/10D (close to longest day length) for 18 months. Tree sparrows showed testicular growth followed by regression and development of photorefractoriness, molting and bill color changes only under long daily photoperiods (12 L and 14 L) but not under short daily photoperiod (9 L). Birds, under stimulatory photoperiods, did not show reinitiation of the above responses after the completion of initiation regression cycle even after their exposure to these photoperiods for 18 months. This precludes the possibility of circannual rhythm generation and suggests the involvement of photoperiodic mechanism in control of their seasonal cycles. Further, replacement of body and primary feathers progressed with gonadal regression only under long days

  16. Failure of photoperiod to alter body growth and carcass composition in beef steers.

    PubMed

    Zinn, S A; Chapin, L T; Enright, W J; Tucker, H A

    1989-05-01

    In each of two experiments, 70 crossbred steers were blocked by BW and assigned to initial slaughter groups or to treatments in a 2 x 2 design. In Exp. 1, treatments were 168 d of photoperiod (8 h of light [L]:16 h of dark [D] or 16L:8D) and plane of nutrition (high energy [HPN] or low energy [LPN]). On d -22, 67 and 155, blood was sampled every 20 min for 8 h. Relative to LPN, HPN increased (P less than .01) ADG by 28%, carcass weight by 26% and accretion of carcass fat by 109% and carcass protein by 20%. On d 155, compared with LPN, HPN increased (P less than .01) serum insulin (INS; 1.09 vs .64 ng/ml) and lowered (P less than .05) growth hormone (GH; 2.14 vs 3.70 ng/ml), but prolactin was not affected. Photoperiod did not affect BW gains, carcass composition or serum hormones. In Exp. 2, treatments were 113 d of photoperiod (8L:16D or 16L:8D) and Synovex-S implant (presence [IMP] or absence [NONIMP]). On d 93, blood was sampled every 30 min for 10 h. Relative to NONIMP, IMP increased (P less than .01) ADG by 12% and accretion of carcass protein by 16%. Implants did not affect carcass weight or accretion of fat. Compared with NONIMP, IMP increased (P less than .05) GH (3.16 vs 2.39 ng/ml) and INS (.68 vs .46 ng/ml) but did not affect PRL. Photoperiod did not affect BW gain, carcass composition or serum hormones. We conclude that photoperiod fails to influence growth and carcass composition of steers.

  17. Identification of genetically diverse genotypes for photoperiod insensitivity in soybean using RAPD markers.

    PubMed

    Singh, R K; Bhatia, V S; Yadav, Sanjeev; Athale, Rashmi; Lakshmi, N; Guruprasad, K N; Chauhan, G S

    2008-10-01

    Most of the Indian soybean varieties were found to be highly sensitive to photoperiod, which limits their cultivation in only localized area. Identification of genetically diverse source of photoperiod insensitive would help to broaden the genetic base for this trait. Present study was undertaken with RAPD markers for genetic diversity estimation in 44 accessions of soybean differing in response to photoperiod sensitivity. The selected twenty-five RAPD primers produced a total of 199 amplicons, which generated 89.9 % polymorphism. The number of amplification products ranged from 2 to 13 for different primers. The polymorphism information content ranged from 0.0 for monomorphic loci to 0.5 with an average of 0.289. Genetic diversity between pairs of genotypes was 37.7% with a range of 3.9 to 71.6%. UPGMA cluster analysis placed all the accessions of soybean into four major clusters. No discernable geographical patterns were observed in clustering however; the smaller groups corresponded well with pedigree. Mantel's test (r = 0.915) indicates very good fit for clustering pattern. Two genotypes, MACS 330 and 111/2/1939 made a very divergent group from other accessions of soybean and highly photoperiod insensitive that may be potential source for broadening the genetic base of soybean for this trait.

  18. Conventional oil and gas development alters forest songbird communities

    Treesearch

    Emily H. Thomas; Margaret C. Brittingham; Scott H. Stoleson

    2014-01-01

    Energy extraction within forest habitat is increasing at a rapid rate throughout eastern North America from the combined presence of conventional oil and gas, shale gas, and wind energy. We examined the effects of conventional oil and gas development on forest habitat including amounts of core and edge forest, the abundance of songbird species and guilds, species...

  19. Effects of shallow natural gas well structures and associated roads on grassland songbird reproductive success in Alberta, Canada

    PubMed Central

    Koper, Nicola

    2017-01-01

    Grassland songbird populations across North America have experienced dramatic population declines due to habitat loss and degradation. In Canada, energy development continues to fragment and disturb prairie habitat, but effects of oil and gas development on reproductive success of songbirds in North American mixed-grass prairies remains largely unknown. From 2010–2012, in southeastern Alberta, Canada, we monitored 257 nests of two ground-nesting grassland songbird species, Savannah sparrow (Passerculus sandwichensis) and chestnut-collared longspur (Calcarius ornatus). Nest locations varied with proximity to and density of conventional shallow gas well structures and associated roads in forty-two 258-ha mixed-grass prairie sites. We estimated the probabilities of nest success and clutch size relative to gas well structures and roads. There was little effect of distance to or density of gas well structure on nest success; however, Savannah sparrow experienced lower nest success near roads. Clutch sizes were lower near gas well structures and cattle water sources. Minimizing habitat disturbance surrounding gas well structures, and reducing abundance of roads and trails, would help minimize impacts on reproductive success for some grassland songbirds. PMID:28355241

  20. Estradiol-dependent modulation of auditory processing and selectivity in songbirds

    PubMed Central

    Maney, Donna; Pinaud, Raphael

    2011-01-01

    The steroid hormone estradiol plays an important role in reproductive development and behavior and modulates a wide array of physiological and cognitive processes. Recently, reports from several research groups have converged to show that estradiol also powerfully modulates sensory processing, specifically, the physiology of central auditory circuits in songbirds. These investigators have discovered that (1) behaviorally-relevant auditory experience rapidly increases estradiol levels in the auditory forebrain; (2) estradiol instantaneously enhances the responsiveness and coding efficiency of auditory neurons; (3) these changes are mediated by a non-genomic effect of brain-generated estradiol on the strength of inhibitory neurotransmission; and (4) estradiol regulates biochemical cascades that induce the expression of genes involved in synaptic plasticity. Together, these findings have established estradiol as a central regulator of auditory function and intensified the need to consider brain-based mechanisms, in addition to peripheral organ dysfunction, in hearing pathologies associated with estrogen deficiency. PMID:21146556

  1. Major histocompatibility complex class I evolution in songbirds: universal primers, rapid evolution and base compositional shifts in exon 3

    PubMed Central

    Alcaide, Miguel; Liu, Mark

    2013-01-01

    Genes of the Major Histocompatibility Complex (MHC) have become an important marker for the investigation of adaptive genetic variation in vertebrates because of their critical role in pathogen resistance. However, despite significant advances in the last few years the characterization of MHC variation in non-model species still remains a challenging task due to the redundancy and high variation of this gene complex. Here we report the utility of a single pair of primers for the cross-amplification of the third exon of MHC class I genes, which encodes the more polymorphic half of the peptide-binding region (PBR), in oscine passerines (songbirds; Aves: Passeriformes), a group especially challenging for MHC characterization due to the presence of large and complex MHC multigene families. In our survey, although the primers failed to amplify exon 3 from two suboscine passerine birds, they amplified exon 3 of multiple MHC class I genes in all 16 species of oscine songbirds tested, yielding a total of 120 sequences. The 16 songbird species belong to 14 different families, primarily within the Passerida, but also in the Corvida. Using a conservative approach based on the analysis of cloned amplicons (n = 16) from each species, we found between 3 and 10 MHC sequences per individual. Each allele repertoire was highly divergent, with the overall number of polymorphic sites per species ranging from 33 to 108 (out of 264 sites) and the average number of nucleotide differences between alleles ranging from 14.67 to 43.67. Our survey in songbirds allowed us to compare macroevolutionary dynamics of exon 3 between songbirds and non-passerine birds. We found compelling evidence of positive selection acting specifically upon peptide-binding codons across birds, and we estimate the strength of diversifying selection in songbirds to be about twice that in non-passerines. Analysis using comparative methods suggest weaker evidence for a higher GC content in the 3rd codon position of

  2. Songbird ecology in southwestern ponderosa pine forests: A literature review

    Treesearch

    William M. Block; Deborah M. Finch

    1997-01-01

    This publication reviews and synthesizes the literature about ponderosa pine forests of the Southwest, with emphasis on the biology, ecology, and conservation of songbirds. Critical bird-habitat management issues related to succession, snags, old growth, fire, logging, grazing, recreation, and landscape scale are addressed. Overviews of the ecology, current use, and...

  3. Behavioral development and habitat structure affect postfledging movements of songbirds

    Treesearch

    Julianna M. A. Jenkins; Frank R., III Thompson; John Faaborg

    2016-01-01

    Postfledging survival of neotropical migrant songbirds has been linked to seasonal and annual changes in the environment and to individual condition. Understanding what influences variation in postfledging movements may provide insight into the differential value of habitat across life-history stages. We conducted a radio-telemetry study of postfledging ovenbirds (

  4. Bridging of cryptic Borrelia cycles in European songbirds.

    PubMed

    Heylen, Dieter; Krawczyk, Aleksandra; Lopes de Carvalho, Isabel; Núncio, Maria Sofia; Sprong, Hein; Norte, Ana Cláudia

    2017-05-01

    The principal European vector for Borrelia burgdorferi s.l., the causative agents of Lyme disease, is the host-generalist tick Ixodes ricinus. Almost all terrestrial host-specialist ticks have been supposed not to contribute to the terrestrial Borrelia transmission cycles. Through an experiment with blackbirds, we show successful transmission by the widespread I. frontalis, an abundant bird-specialized tick that infests a broad range of songbirds. In the first phase of the experiment, we obtained Borrelia-infected I. frontalis (infection rate: 19%) and I. ricinus (17%) nymphs by exposing larvae to wild blackbirds that carried several genospecies (Borrelia turdi, B. valaisiana, B. burgdorferi s.s.). In the second phase, pathogen-free blackbirds were exposed to these infected nymphs. Both tick species were able to infect the birds, as indicated by the analysis of xenodiagnostic I. ricinus larvae which provided evidence for both co-feeding and systemic transmission (infection rates: 10%-60%). Ixodes frontalis was shown to transmit B. turdi spirochetes, while I. ricinus transmitted both B. turdi and B. valaisiana. Neither species transmitted B. burgdorferi s.s. European enzootic cycles of Borrelia between songbirds and their ornithophilic ticks do exist, with I. ricinus potentially acting as a bridging vector towards mammals, including man. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  5. Cross-hemisphere migration of a 25 g songbird

    PubMed Central

    Bairlein, Franz; Norris, D. Ryan; Nagel, Rolf; Bulte, Marc; Voigt, Christian C.; Fox, James W.; Hussell, David J. T.; Schmaljohann, Heiko

    2012-01-01

    The northern wheatear (Oenanthe oenanthe) is a small (approx. 25 g), insectivorous migrant with one of the largest ranges of any songbird in the world, breeding from the eastern Canadian Arctic across Greenland, Eurasia and into Alaska (AK). However, there is no evidence that breeding populations in the New World have established overwintering sites in the Western Hemisphere. Using light-level geolocators, we demonstrate that individuals from these New World regions overwinter in northern sub-Sahara Africa, with Alaskan birds travelling approximately 14 500 km each way and an eastern Canadian Arctic bird crossing a wide stretch of the North Atlantic (approx. 3500 km). These remarkable journeys, particularly for a bird of this size, last between one to three months depending on breeding location and season (autumn/spring) and result in mean overall migration speeds of up to 290 km d−1. Stable-hydrogen isotope analysis of winter-grown feathers sampled from breeding birds generally support the notion that Alaskan birds overwinter primarily in eastern Africa and eastern Canadian Arctic birds overwinter mainly in western Africa. Our results provide the first evidence of a migratory songbird capable of linking African ecosystems of the Old World with Arctic regions of the New World. PMID:22337504

  6. Cross-hemisphere migration of a 25 g songbird.

    PubMed

    Bairlein, Franz; Norris, D Ryan; Nagel, Rolf; Bulte, Marc; Voigt, Christian C; Fox, James W; Hussell, David J T; Schmaljohann, Heiko

    2012-08-23

    The northern wheatear (Oenanthe oenanthe) is a small (approx. 25 g), insectivorous migrant with one of the largest ranges of any songbird in the world, breeding from the eastern Canadian Arctic across Greenland, Eurasia and into Alaska (AK). However, there is no evidence that breeding populations in the New World have established overwintering sites in the Western Hemisphere. Using light-level geolocators, we demonstrate that individuals from these New World regions overwinter in northern sub-Sahara Africa, with Alaskan birds travelling approximately 14 500 km each way and an eastern Canadian Arctic bird crossing a wide stretch of the North Atlantic (approx. 3500 km). These remarkable journeys, particularly for a bird of this size, last between one to three months depending on breeding location and season (autumn/spring) and result in mean overall migration speeds of up to 290 km d(-1). Stable-hydrogen isotope analysis of winter-grown feathers sampled from breeding birds generally support the notion that Alaskan birds overwinter primarily in eastern Africa and eastern Canadian Arctic birds overwinter mainly in western Africa. Our results provide the first evidence of a migratory songbird capable of linking African ecosystems of the Old World with Arctic regions of the New World.

  7. Photoperiodic Diapause and the Establishment of Aedes albopictus (Diptera: Culicidae) in North America

    PubMed Central

    2016-01-01

    The invasion and range expansion of Aedes albopictus (Skuse) in North America represents an outstanding opportunity to study processes of invasion, range expansion, and climatic adaptation. Furthermore, knowledge obtained from such research is relevant to developing novel strategies to control this important vector species. Substantial evidence indicates that the photoperiodic diapause response is an important adaptation to climatic variation across the range of Ae. albopictus in North America. Photoperiodic diapause is a key determinant of abundance in both space and time, and the timing of entry into and exit out of diapause strongly affects seasonal population dynamics and thus the potential for arbovirus transmission. Emerging genomic technologies are making it possible to develop high-resolution, genome-wide genetic markers that can be used for genetic mapping of traits relevant to disease transmission and phylogeographic studies to elucidate invasion history. Recent work using next-generation sequencing technologies (e.g., RNA-seq), combined with physiological experiments, has provided extensive insight into the transcriptional basis of the diapause response in Ae. albopictus. Applying this knowledge to identify novel targets for vector control represents an important future challenge. Finally, recent studies have begun to identify traits other than diapause that are affected by photoperiodism. Extending this work to identify additional traits influenced by photoperiod should produce important insights into the seasonal biology of Ae. albopictus. PMID:27354438

  8. How annual course of photoperiod shapes seasonal behavior of diploid and triploid oysters, Crassostrea gigas

    PubMed Central

    Payton, Laura; Sow, Mohamedou; Massabuau, Jean-Charles; Ciret, Pierre

    2017-01-01

    In this work, we study if ploidy (i.e. number of copies of chromosomes) in the oyster Crassostrea gigas may introduce differences in behavior and in its synchronization by the annual photoperiod. To answer to the question about the effect of the seasonal course of the photoperiod on the behavior of C. gigas according to its ploidy, we quantified valve activity by HFNI valvometry in situ for 1 year in both diploid and triploid oysters. Chronobiological analyses of daily, tidal and lunar rhythms were performed according the annual change of the photoperiod. In parallel, growth and gametogenesis status were measured and spawning events were detected by valvometry. The results showed that triploids had reduced gametogenesis, without spawning events, and approximately three times more growth than diploids. These differences in physiological efforts could explain the result that photoperiod (daylength and/or direction of daylength) differentially drives and modulates seasonal behavior of diploid and triploid oysters. Most differences were observed during long days (spring and summer), where triploids showed longer valve opening duration but lower opening amplitude, stronger daily rhythm and weaker tidal rhythm. During this period, diploids did major gametogenesis and spawning whereas triploids did maximal growth. Differences were also observed in terms of moonlight rhythmicity and neap-spring tidal cycle rhythmicity. We suggest that the seasonal change of photoperiod differentially synchronizes oyster behavior and biological rhythms according to physiological needs based on ploidy. PMID:29020114

  9. How annual course of photoperiod shapes seasonal behavior of diploid and triploid oysters, Crassostrea gigas.

    PubMed

    Payton, Laura; Sow, Mohamedou; Massabuau, Jean-Charles; Ciret, Pierre; Tran, Damien

    2017-01-01

    In this work, we study if ploidy (i.e. number of copies of chromosomes) in the oyster Crassostrea gigas may introduce differences in behavior and in its synchronization by the annual photoperiod. To answer to the question about the effect of the seasonal course of the photoperiod on the behavior of C. gigas according to its ploidy, we quantified valve activity by HFNI valvometry in situ for 1 year in both diploid and triploid oysters. Chronobiological analyses of daily, tidal and lunar rhythms were performed according the annual change of the photoperiod. In parallel, growth and gametogenesis status were measured and spawning events were detected by valvometry. The results showed that triploids had reduced gametogenesis, without spawning events, and approximately three times more growth than diploids. These differences in physiological efforts could explain the result that photoperiod (daylength and/or direction of daylength) differentially drives and modulates seasonal behavior of diploid and triploid oysters. Most differences were observed during long days (spring and summer), where triploids showed longer valve opening duration but lower opening amplitude, stronger daily rhythm and weaker tidal rhythm. During this period, diploids did major gametogenesis and spawning whereas triploids did maximal growth. Differences were also observed in terms of moonlight rhythmicity and neap-spring tidal cycle rhythmicity. We suggest that the seasonal change of photoperiod differentially synchronizes oyster behavior and biological rhythms according to physiological needs based on ploidy.

  10. Effect of photoperiod prior to cold acclimation on freezing tolerance and carbohydrate metabolism in alfalfa (Medicago sativa L.).

    PubMed

    Bertrand, Annick; Bipfubusa, Marie; Claessens, Annie; Rocher, Solen; Castonguay, Yves

    2017-11-01

    Cold acclimation proceeds sequentially in response to decreases in photoperiod and temperature. This study aimed at assessing the impact of photoperiod prior to cold acclimation on freezing tolerance and related biochemical and molecular responses in two alfalfa cultivars. The fall dormant cultivar Evolution and semi-dormant cultivar 6010 were grown in growth chambers under different photoperiods (8, 10, 12, 14 or 16h) prior to cold acclimation. Freezing tolerance was evaluated as well as carbohydrate concentrations, levels of transcripts encoding enzymes of carbohydrate metabolism as well as a K-3dehydrin, before and after cold acclimation. The fall dormant cultivar Evolution had a better freezing tolerance than the semi-dormant cultivar 6010. The effect of photoperiod prior to cold acclimation on the level of freezing tolerance differed between the two cultivars: an 8h-photoperiod induced the highest level of freezing tolerance in Evolution and the lowest in 6010. In Evolution, the 8h-induced superior freezing tolerance was associated with higher concentration of raffinose-family oligosaccharides (RFO). The transcript levels of sucrose synthase (SuSy) decreased whereas those of sucrose phosphatase synthase (SPS) and galactinol synthase (GaS) increased in response to cold acclimation in both cultivars. Our results indicate that RFO metabolism could be involved in short photoperiod-induced freezing tolerance in dormant alfalfa cultivars. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  11. Effect of differential photoperiod treatment on Leydig cell ultrastructure in the bank vole (Clethrionomys glareolus, S.).

    PubMed

    Tähkä, K M

    1988-08-01

    Juvenile bank voles (18-22 days of age) born and reared in a stimulatory long photoperiod (18L:6D, lights on 0600-2400 hr) were subjected either to a long photoperiod (18L:6D, Group L) or to a short photoperiod (6L:18D, lights on 0800-1400 hr, Group S) for 6 to 8 weeks whereafter the animals were killed by decapitation. Possible photoperiod-induced changes in Leydig cell ultrastructure were studied by conventional transmission electron microscopy and stereological methods. Striking differences in Leydig cell ultrastructure between the experimental groups were encountered. Light deprivation induced a marked decrease in the cytoplasmic and nuclear volume as well as in the amounts of smooth endoplasmic reticulum (SER), rough endoplasmic reticulum, mitochondria, and lipid inclusions in the Leydig cells. The number of myelin bodies and dense bodies seemed to be somewhat higher in the regressive Group S Leydig cells. These results are in good agreement with our previous histological and biochemical studies on the effects of photoperiod on Leydig cell function and suggest that in the bank vole the volume of mitochondria and SER in particular correlates positively with the steroidogenic capacity (the activity of C20 alpha 22-C27 desmolase, 17 alpha-hydroxylase, and C17-20 lyase in particular) in the Leydig cell.

  12. Effects of Varying Photoperiodic Regimens on Critical Biological Fitness Traits of Culex quinquefasciatus (Diptera: Culicidae) Mosquito Vector

    PubMed Central

    Ukubuiwe, Azubuike Christian; Olayemi, Israel Kayode; Omalu, Innocent Chukwuemeka James; Arimoro, Francis Ofurum; Baba, Bulus Musa; Ukubuiwe, Chinenye Catherine

    2018-01-01

    This study investigated the effects of varying photoperiodic conditions on critical life stages’ parameters of Culex quinquefasciatus. To this end, first larval stage was reared under different constant photoperiodic regimens: 0, 6 (short), 12 (equal), 13 (prevailing condition), and 18 and 24 (long) hours of light (hL). Duration of development, survivorship, emergence successes, adult longevity, caloric indices (CIs), and utilisation of teneral reserves for metamorphosis at each regimen were monitored. Analyses revealed significant negative effects of increasing photoperiod on all entomological variables measured. Short photo-phases elicited faster development times, increased life stages’ survivorship and number at emergence, adult longevity, and CI for all life stages while increasing teneral components for adult life traits. The information generated in this study is important in understanding the role played by photoperiod in disease transmission and for development of integrated vector control strategies based on environmental manipulation. PMID:29636636

  13. Effect of Light Intensity and Photoperiod on Growth and Biochemical Composition of a Local Isolate of Nostoc calcicola.

    PubMed

    Khajepour, Fateme; Hosseini, Seyed Abbas; Ghorbani Nasrabadi, Rasoul; Markou, Giorgos

    2015-08-01

    A study was conducted to investigate the effect of light intensity (21, 42, and 63 μmol photons m(-2) s(-1)) and photoperiod (8:16, 12:12, and 16:8 h light/dark) on the biomass production and its biochemical composition (total carotenoids, chlorophyll a, phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC), total protein, and carbohydrates) of a local isolate of Nostoc calcicola. The results revealed that N. calcicola prefers dim light; however, the most of the levels of light intensity and photoperiod investigated did not have a significant impact on biomass production. Increasing light intensity biomass content of chlorophyll a, PE, PC, APC, and total protein decreased, while total carotenoids and carbohydrate increased. The same behavior was observed also when light duration (photoperiod) increased. The interaction effect of increasing light intensity and photoperiod resulted in an increase of carbohydrate and total carotenoids, and to the decrease of chlorophyll a, PE, PC, APC, and total protein content. The results indicate that varying the light regime, it is capable to manipulate the biochemical composition of the local isolate of N. calcicola, producing either valuable phycobiliproteins or proteins under low light intensity and shorter photoperiods, or producing carbohydrates and carotenoids under higher light intensities and longer photoperiods.

  14. Patterns of testosterone in three Nearctic-Neotropical migratory songbirds during spring passage.

    PubMed

    Covino, Kristen M; Morris, Sara R; Moore, Frank R

    2015-12-01

    Preparation for breeding may overlap extensively with vernal migration in long-distance migratory songbirds. Testosterone plays a central role in mediating this transition into breeding condition by facilitating changes to physiology and behavior. While changes in testosterone levels are well studied in captive migrants, these changes are less well known in free-living birds. We examined testosterone levels in free-living Nearctic-Neotropical migrants of three species during their vernal migration. Testosterone levels increased during the migratory period in males of all three species but significantly so in only two. Testosterone levels in females remained the same throughout their migration. Our results support the extensive overlap between vernal migration and breeding preparation in male songbirds. The pattern of testosterone changes during vernal migration is far from clear in females. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Development and Seed Number in Indeterminate Soybean as Affected by Timing and Duration of Exposure to Long Photoperiods after Flowering

    PubMed Central

    Kantolic, Adriana G.; Slafer, Gustavo A.

    2007-01-01

    Background and Aims Long photoperiods from flowering to maturity have been found to delay reproductive development in soybean (Glycine max) and to increase the number of seeds per unit land area. This study was aimed to evaluate whether sensitivity to photoperiod after flowering (a) is quantitatively related to the length of exposure to long days and (b) persists throughout the whole pod-setting period. It was also evaluated whether seed number was related to changes in the duration of post-flowering phenophases. Methods Two field experiments were conducted with an indeterminate cultivar of soybean of maturity group V. In expt 1, photoperiods 2 h longer than natural daylength were applied during different numbers of days from the beginning pod stage (R3) onwards, while in expt 2 these photoperiod extensions were imposed during 9 consecutive days starting at different times between R3 and R6 (full seed) stages. Key Results There was a quantitative response of development to the number of cycles with a long photoperiod. The exposure to long photoperiods from R3 to R5 (beginning of seed growth) increased the duration of R3–R6 regardless of the timing of exposure. The stages of development comprised in the R3–R6 phase were delayed by current as well as by previous exposure to long days. A positive relationship was found between seed number and the duration of R3–R6, irrespective of the timing and length of exposure to the long photoperiod. Conclusions Sensitivity to photoperiod remained high during the reproductive period and was highly and positively coupled with the processes of generation of yield. PMID:17452381

  16. The role of the pineal gland in the photoperiodic control of bird song frequency and repertoire in the house sparrow, Passer domesticus.

    PubMed

    Wang, Gang; Harpole, Clifford E; Paulose, Jiffin; Cassone, Vincent M

    2014-04-01

    Temperate zone birds are highly seasonal in many aspects of their physiology. In mammals, but not in birds, the pineal gland is an important component regulating seasonal patterns of primary gonadal functions. Pineal melatonin in birds instead affects seasonal changes in brain song control structures, suggesting the pineal gland regulates seasonal song behavior. The present study tests the hypothesis that the pineal gland transduces photoperiodic information to the control of seasonal song behavior to synchronize this important behavior to the appropriate phenology. House sparrows, Passer domesticus, expressed a rich array of vocalizations ranging from calls to multisyllabic songs and motifs of songs that varied under a regimen of different photoperiodic conditions that were simulated at different times of year. Control (SHAM) birds exhibited increases in song behavior when they were experimentally transferred from short days, simulating winter, to equinoctial and long days, simulating summer, and decreased vocalization when they were transferred back to short days. When maintained in long days for longer periods, the birds became reproductively photorefractory as measured by the yellowing of the birds' bills; however, song behavior persisted in the SHAM birds, suggesting a dissociation of reproduction from the song functions. Pinealectomized (PINX) birds expressed larger, more rapid increases in daily vocal rate and song repertoire size than did the SHAM birds during the long summer days. These increases gradually declined upon the extension of the long days and did not respond to the transfer to short days as was observed in the SHAM birds, suggesting that the pineal gland conveys photoperiodic information to the vocal control system, which in turn regulates song behavior. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Epidemiology of a Salmonella enterica subsp. Enterica serovar Typhimurium strain associated with a songbird outbreak.

    USGS Publications Warehouse

    Blehert, David S.; Hernandez, Sonia M.; Keel, Kevin; Sanchez, Susan; Trees, Eija; ,

    2012-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.

  18. Songbirds as Sentinels of Mercury in Terrestrial Foodwebs of Eastern North America

    EPA Science Inventory

    Mercury is a globally distributed environmental contaminant with a variety of deleterious effects in fish, wildlife, and humans. Breeding songbirds may be useful sentinels for mercury because they are relatively easy to sample, have well-defined and small territories, and integra...

  19. Young Stand Thinning and Diversity Study: Response of Songbird Community One Decade Post-Treatment

    USGS Publications Warehouse

    Hagar, Joan; Friesen, Cheryl

    2009-01-01

    The response of songbird assemblages to commercial thinning is likely to change as vegetation develops over time after thinning. The influence of thinning intensity and pattern on the timing of transitions in bird community composition following thinning is of interest to managers when a goal is to maintain diversity and accelerate the development of late-seral forest structure. We investigated changes in the composition of songbird assemblages and density of individual species from 2 years before to 12 years after experimental thinning of 40-year-old stands dominated by Douglas-fir (Pseudotsuga menziesii) in the Oregon Cascades. Species richness, and density for five species and the neotropical migrant group were greater in thinned than in unthinned control stands over all post-treatment years of the study. Similarly, three species maintained a negative response to thinning over the post-treatment period. The initial positive influence of thinning was no longer in evidence a decade after harvest for five species. Of seven species with an initial negative response to thinning, three indicated recovery towards pre-treatment densities by the end of the most recent post-treatment survey. Our study is one of the first to document long-term effects of commercial thinning on forest songbird assemblages in the Pacific Northwest.

  20. Reproductive status of overwintering potato psyllid: absence of photoperiod effects

    USDA-ARS?s Scientific Manuscript database

    We examined the effects of photoperiod on reproductive diapause of three haplotypes of potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae), collected from three geographic locations: south Texas (Central haplotype), California (Western haplotype), and Washington State (Northwestern haploty...

  1. Influence of Photoperiod on Hormones, Behavior, and Immune Function

    PubMed Central

    Walton, James C.; Weil, Zachary M.; Nelson, Randy J.

    2011-01-01

    Photoperiodism is the ability of plants and animals to measure environmental day length to ascertain time of year. Central to the evolution of photoperiodism in animals is the adaptive distribution of energetically challenging activities across the year to optimize reproductive fitness while balancing the energetic tradeoffs necessary for seasonally- appropriate survival strategies. The ability to accurately predict future events requires endogenous mechanisms to permit physiological anticipation of annual conditions. Day length provides a virtually noise free environmental signal to monitor and accurately predict time of the year. In mammals, melatonin provides the hormonal signal transducing day length. Duration of pineal melatonin is inversely related to day length and its secretion drives enduring changes in many physiological systems, including the HPA, HPG, and brain-gut axes, the autonomic nervous system, and the immune system. Thus, melatonin is the fulcrum mediating redistribution of energetic investment among physiological processes to maximize fitness and survival. PMID:21156187

  2. The joint influence of photoperiod and temperature during growth cessation and development of dormancy in white spruce (Picea glauca).

    PubMed

    Hamilton, Jill A; El Kayal, Walid; Hart, Ashley T; Runcie, Daniel E; Arango-Velez, Adriana; Cooke, Janice E K

    2016-11-01

    Timely responses to environmental cues enable the synchronization of phenological life-history transitions essential for the health and survival of north-temperate and boreal tree species. While photoperiodic cues will remain persistent under climate change, temperature cues may vary, contributing to possible asynchrony in signals influencing developmental and physiological transitions essential to forest health. Understanding the relative contribution of photoperiod and temperature as determinants of the transition from active growth to dormancy is important for informing adaptive forest management decisions that consider future climates. Using a combination of photoperiod (long = 20 h or short = 8 h day lengths) and temperature (warm = 22 °C/16 °C and cool = 8 °C/4 °C day/night, respectively) treatments, we used microscopy, physiology and modeling to comprehensively examine hallmark traits of the growth-dormancy transition-including bud formation, growth cessation, cold hardiness and gas exchange-within two provenances of white spruce [Picea glauca (Moench) Voss] spanning a broad latitude in Alberta, Canada. Following exposure to experimental treatments, seedlings were transferred to favorable conditions, and the depth of dormancy was assessed by determining the timing and ability of spruce seedlings to resume growth. Short photoperiods promoted bud development and growth cessation, whereas longer photoperiods extended the growing season through the induction of lammas growth. In contrast, cool temperatures under both photoperiodic conditions delayed bud development. Photoperiod strongly predicted the development of cold hardiness, whereas temperature predicted photosynthetic rates associated with active growth. White spruce was capable of attaining endodormancy, but its release was environmentally determined. Dormancy depth varied substantially across experimental treatments suggesting that environmental cues experienced within one season could affect growth

  3. Relative roles of temperature and photoperiod as drivers of metabolic flexibility in dark-eyed juncos.

    PubMed

    Swanson, David; Zhang, Yufeng; Liu, Jin-Song; Merkord, Christopher L; King, Marisa O

    2014-03-15

    Seasonal phenotypic flexibility in small birds produces a winter phenotype with elevated maximum cold-induced metabolic rates (=summit metabolism, Msum). Temperature and photoperiod are candidates for drivers of seasonal phenotypes, but their relative impacts on metabolic variation are unknown. We examined photoperiod and temperature effects on Msum, muscle masses and activities of key catabolic enzymes in winter dark-eyed juncos (Junco hyemalis). We randomly assigned birds to four treatment groups varying in temperature (cold=3°C; warm=24°C) and photoperiod [short day (SD)=8 h:16 h light:dark; long day (LD)=16 h:8 h light:dark] in a two-by-two design. We measured body mass (Mb), flight muscle width and Msum before and after 3 and 6 weeks of acclimation, and flight muscle and heart masses after 6 weeks. Msum increased for cold-exposed, but not for warm-exposed, birds. LD birds gained more Mb than SD birds, irrespective of temperature. Flight muscle size and mass did not differ significantly among groups, but heart mass was larger in cold-exposed birds. Citrate synthase, carnitine palmitoyl transferase and β-hydroxyacyl Co-A dehydrogenase activities in the pectoralis were generally higher for LD and cold groups. The cold-induced changes in Msum and heart mass parallel winter changes for small birds, but the larger Mb and higher catabolic enzyme activities in LD birds suggest photoperiod-induced changes associated with migratory disposition. Temperature appears to be a primary driver of flexibility in Msum in juncos, but photoperiod-induced changes in Mb and catabolic enzyme activities, likely associated with migratory disposition, interact with temperature to contribute to seasonal phenotypes.

  4. Control of annual reproductive cycle in the subtropical house sparrow (Passer domesticus): evidence for conservation of photoperiodic control mechanisms in birds

    PubMed Central

    Trivedi, Amit K; Rani, Sangeeta; Kumar, Vinod

    2006-01-01

    Background In many birds, day length (=photoperiod) regulates reproductive cycle. The photoperiodic environment varies between different seasons and latitudes. As a consequence, species at different latitudes may have evolved separate photoperiodic strategies or modified them as per their adaptive need. We studied this using house sparrow as a model since it is found worldwide and is widely investigated. In particular, we examined whether photoperiodism in house sparrows (Passer domesticus) at 27°N, 81°E shared features with those exhibited by its conspecifics at high latitudes. Results Initial experiment described in the wild and captive conditions the gonad development and molt (only in captives) cycles over a 12-month period. Both male and female sparrows had similar seasonal cycles, linked with annual variations in day length; this suggested that seasonal reproduction in house sparrows was under the photoperiodic control. However, a slower testis and attenuated follicular growth among captives indicated that other (supplementary) factors are also involved in controlling the reproductive cycle. Next experiment examined if sparrows underwent seasonal variations in their response to stimulatory effects of long day lengths. When birds were transferred every month over a period of 1 year to 16 hours light:8 hours darkness (16L:8D) for 17–26 weeks, there was indeed a time-of-year effect on the growth-regression cycle of gonads. The final experiment investigated response of house sparrows to a variety of light-dark (LD) cycles. In the first set, sparrows were exposed for 31 weeks to photoperiods that were close to what they receive in between the period from sunrise to sunset at this latitude: 9L:15D (close to shortest day length in December), 12L:12D (equinox, in March and September) 15L:9D (close to longest day length in June). They underwent testicular growth and regression and molt in 12L and 15L photoperiods, but not in 9L photoperiod. In the second set

  5. A conceptual framework for clutch-size evolution in songbirds.

    PubMed

    Martin, Thomas E

    2014-03-01

    Causes of evolved differences in clutch size among songbird species remain debated. I propose a new conceptual framework that integrates aspects of traditional life-history theory while including novel elements to explain evolution of clutch size among songbirds. I review evidence that selection by nest predation on length of time that offspring develop in the nest creates a gradient in offspring characteristics at nest leaving (fledging), including flight mobility, spatial dispersion, and self-feeding rate. I postulate that this gradient has consequences for offspring mortality rates and parental energy expenditure per offspring. These consequences then determine how reproductive effort is partitioned among offspring, while reproductive effort evolves from age-specific mortality effects. Using data from a long-term site in Arizona, as well as from the literature, I provide support for hypothesized relationships. Nestling development period consistently explains fledgling mortality, energy expenditure per offspring, and clutch size while accounting for reproductive effort (i.e., total energy expenditure) to thereby support the framework. Tests in this article are not definitive, but they document previously unrecognized relationships and address diverse traits (developmental strategies, parental care strategies, energy requirements per offspring, evolution of reproductive effort, clutch size) that justify further investigations of hypotheses proposed here.

  6. A conceptual framework for clutch size evolution in songbirds

    USGS Publications Warehouse

    Martin, Thomas E.

    2014-01-01

    Causes of evolved differences in clutch size among songbird species remain debated. I propose a new conceptual framework that integrates aspects of traditional life history theory, while including novel elements, to explain evolution of clutch size among songbirds. I review evidence that selection by nest predation on length of time that offspring develop in the nest creates a gradient in offspring characteristics at nest-leaving (fledging), including flight mobility, spatial dispersion, and self-feeding rate. I postulate that this gradient has consequences for offspring mortality rates and parental energy expenditure per offspring. These consequences then determine how reproductive effort is partitioned among offspring, while reproductive effort evolves from age-specific mortality effects. Using data from a long-term site in Arizona, as well as from the literature, I provide support for hypothesized relationships. Nestling development period consistently explains fledgling mortality, energy expenditure per offspring, and clutch size while accounting for reproductive effort (i.e., total energy expenditure) to thereby support the framework. Tests in this paper are not definitive, but they document previously unrecognized relationships and address diverse traits (developmental strategies, parental care strategies, energy requirements per offspring, evolution of reproductive effort, clutch size) that justify further investigations of hypotheses proposed here.

  7. Dawn song in natural and artificial continuous day: Light pollution affects songbirds at high latitudes.

    PubMed

    Derryberry, Elizabeth P

    2017-10-01

    In Focus: Da Silva, A., & Kempenaers, B. (2017). Singing from North to South: Latitudinal variation in timing of dawn singing under natural and artificial light conditions. Journal of Animal Ecology, 86, 1286-1297. doi: 10.1111/1365-2656.12739 Satellite images of the world at night show bright dots connected by glowing lines crisscrossing the globe. As these connect-the-dots become brighter and expand into more and more remote regions, much of the flora and fauna of the world are experiencing evolutionarily unprecedented levels of light at night. Light cues are essential to most physiological and behavioural processes, and so the need to measure the effects of light pollution on these processes is critical. In this issue, Da Silva and Kempenaers take on this task using an important reproductive behaviour in songbirds-dawn song. The geographic, temporal and taxonomic breadth of sampling in this study allows for a close examination of a potentially complex interaction between light pollution and natural variation in the behaviour of dawn singing across latitude, season and species. Their extensive dataset highlights complexity in how songbirds respond to light pollution. Although light pollution has a strong effect on the timing of dawn song, not all songbirds respond the same way to light pollution, and the effects of light pollution vary with changes in natural light levels. Early dawn singers show more flexibility in the timing of dawn song across the season and across latitudes than late dawn singers, and also appear less affected by light pollution at high latitudes than are late dawn singers. These findings suggest that not all songbirds are responding to artificial continuous daylight as they do to natural continuous daylight, highlighting the general need to measure the fitness effects of light pollution. © 2017 The Author. Journal of Animal Ecology © 2017 British Ecological Society.

  8. Minimizing marker mass and handling time when attaching radio-transmitters and geolocators to small songbirds

    USGS Publications Warehouse

    Streby, Henry M.; McAllister, Tara L.; Peterson, Sean M.; Kramer, Gunnar R.; Lehman, Justin A.; Andersen, David E.

    2015-01-01

    Radio-transmitters and light-level geolocators are currently small enough for use on songbirds weighing <15 g. Various methods are used to attach these markers to larger songbirds, but with small birds it becomes especially important to minimize marker mass and bird handling time. Here, we offer modifications to harness materials and marker preparation for transmitters and geolocators, and we describe deployment methods that can be safely completed in 20–60 s per bird. We describe a 0.5-mm elastic sewing thread harness for radio-transmitters that allows nestlings, fledglings, and adults to be marked with the same harness size and reliably falls off to avoid poststudy effects. We also describe a 0.5-mm jewelry cord harness for geolocators that provides a firm fit for >1 yr. Neither harness type requires plastic or metal tubes, rings, or other attachment fixtures on the marker, nor do they require crimping beads, epoxy, scissors, or tying knots while handling birds. Both harnesses add 0.03 g to the mass of markers for small wood-warblers (Parulidae). This minimal additional mass is offset by trimming transmitter antennas or geolocator connection nodes, resulting in no net mass gain for transmitters and 0.02 g added for geolocators compared with conventional harness methods that add >0.40 g. We and others have used this transmitter attachment method with several small songbird species, with no effects on adult and fledgling behavior and survival. We have used this geolocator attachment method on 9-g wood-warblers with no effects on return rates, return dates, territory fidelity, and body mass. We hope that these improvements to the design and deployment of the leg-loop harness method will enable the safe and successful use of these markers, and eventually GPS and other tags, on similarly small songbirds.

  9. Constant and changing photoperiods in the laying period for broiler breeders allowed [corrected] normal or accelerated growth during the rearing period.

    PubMed

    Lewis, P D; Gous, R M

    2006-02-01

    Broiler breeder pullets were grown on 8-h photoperiods to 2.23 or 2.42 kg of BW at 20 wk, and then transferred abruptly to 11- or 16-h photoperiods. Subsequently, some of the 11-h photoperiod birds were given 15-min increases in day length weekly or a 1-h increase every 4 wk to reach 16 h of light at 54 wk. The birds transferred abruptly to a 16-h photoperiod at 20 wk matured 4 d earlier than 11-h photoperiod birds, required 500 g less feed to reach 50% lay, but, because of a 3% lower rate of lay after peak, produced 5 fewer eggs to 60 wk. However, the number of settable eggs was similar for the 2 groups because the 11-h photoperiod birds laid more eggs on the floor, resulting in more cracked and dirty eggs. The 11-h photoperiod birds converted feed into egg more efficiently, and were 100 g heavier at end of lay. Increasing the photoperiod in 15-min or 1-h increments from 11 to 16 h during the laying cycle depressed egg production. Mean egg weight and mortality were similar for all lighting groups. The heavier BW birds at 20 wk reached maturity 1 d earlier, but used 1 kg more feed to reach maturity, laid 5 fewer total eggs (because of a 3% lower rate of lay after peak), produced 7 more unsettable eggs (because more eggs were laid on the floor), and converted feed into egg less efficiently than did the lighter BW birds. Mean egg weight, BW at 57 wk, and mortality were similar for both groups. There was no significant light x growth interaction for any performance parameter. It is concluded that there is no benefit to egg production from extending the photoperiod to 16 h when broiler breeders are kept in light-proofed housing, especially if they have access to illuminated nest boxes.

  10. Major QTLs for critical photoperiod and vernalization underlie extensive variation in flowering in the Mimulus guttatus species complex.

    PubMed

    Friedman, Jannice; Willis, John H

    2013-07-01

    Species with extensive ranges experience highly variable environments with respect to temperature, light and soil moisture. Synchronizing the transition from vegetative to floral growth is important to employ favorable conditions for reproduction. Optimal timing of this transition might be different for semelparous annual plants and iteroparous perennial plants. We studied variation in the critical photoperiod necessary for floral induction and the requirement for a period of cold-chilling (vernalization) in 46 populations of annuals and perennials in the Mimulus guttatus species complex. We then examined critical photoperiod and vernalization QTLs in growth chambers using F(2) progeny from annual and perennial parents that differed in their requirements for flowering. We identify extensive variation in critical photoperiod, with most annual populations requiring substantially shorter day lengths to initiate flowering than perennial populations. We discover a novel type of vernalization requirement in perennial populations that is contingent on plants experiencing short days first. QTL analyses identify two large-effect QTLs which influence critical photoperiod. In two separate vernalization experiments we discover each set of crosses contain different large-effect QTLs for vernalization. Mimulus guttatus harbors extensive variation in critical photoperiod and vernalization that may be a consequence of local adaptation. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  11. Promotion of flowering in azaleas by manipulating photoperiod and temperature induces epigenetic alterations during floral transition.

    PubMed

    Meijón, Mónica; Feito, Isabel; Valledor, Luis; Rodríguez, Roberto; Cañal, María Jesús

    2011-09-01

    The ability to control the timing of flowering is a key strategy for planning production in ornamental species such as the azalea; however, this requires a thorough understanding of floral induction pathways. DNA methylation is one of the main mechanisms involved in controlling the functional state of chromatin and gene expression in response to environmental and developmental signals. This work investigated the promotion of flowering in azaleas by the manipulation of environmental factors, using DNA methylation levels as a marker of floral bud development. The results showed that the change of long-day (LD) to short-day (SD) photoperiod is the primary factor responsible for floral induction in azaleas, whereas the existence of the previous cold period as well as the physiological memory are factors which improve floral production. Furthermore, for blooming to take place, 1300 units of growing degree days under an LD were necessary. The promotion of flowering in azaleas by alterations of photoperiod and temperature induced DNA methylation changes. The demethylation observed after the change from LD to SD is linked to a change in cell fate which is necessary for floral transition to take place and seems to be associated with the floral signal. Copyright © Physiologia Plantarum 2011.

  12. Transcriptome responses to temperature, water availability and photoperiod are conserved among mature trees of two divergent Douglas-fir provenances from a coastal and an interior habitat.

    PubMed

    Hess, Moritz; Wildhagen, Henning; Junker, Laura Verena; Ensminger, Ingo

    2016-08-26

    Local adaptation and phenotypic plasticity are important components of plant responses to variations in environmental conditions. While local adaptation has been widely studied in trees, little is known about plasticity of gene expression in adult trees in response to ever changing environmental conditions in natural habitats. Here we investigate plasticity of gene expression in needle tissue between two Douglas-fir provenances represented by 25 adult trees using deep RNA sequencing (RNA-Seq). Using linear mixed models we investigated the effect of temperature, soil water availability and photoperiod on the abundance of 59189 detected transcripts. Expression of more than 80 % of all identified transcripts revealed a response to variations in environmental conditions in the field. GO term overrepresentation analysis revealed gene expression responses to temperature, soil water availability and photoperiod that are highly conserved among many plant taxa. However, expression differences between the two Douglas-fir provenances were rather small compared to the expression differences observed between individual trees. Although the effect of environment on global transcript expression was high, the observed genotype by environment (GxE) interaction of gene expression was surprisingly low, since only 21 of all detected transcripts showed a GxE interaction. The majority of the transcriptome responses in plant leaf tissue is driven by variations in environmental conditions. The small variation between individuals and populations suggests strong conservation of this response within Douglas-fir. Therefore we conclude that plastic transcriptome responses to variations in environmental conditions are only weakly affected by local adaptation in Douglas-fir.

  13. Nest mortality of sagebrush songbirds due to a severe hailstorm

    USGS Publications Warehouse

    Hightower, Jessica N.; Carlisle, Jason D.; Chalfoun, Anna D.

    2018-01-01

    Demographic assessments of nesting birds typically focus on failures due to nest predation or brood parasitism. Extreme weather events such as hailstorms, however, can also destroy eggs and injure or kill juvenile and adult birds at the nest. We documented the effects of a severe hailstorm on 3 species of sagebrush-associated songbirds: Sage Thrasher (Oreoscoptes montanus), Brewer's Sparrow (Spizella breweri), and Vesper Sparrow (Pooecetes gramineus), nesting at eight 24 ha study plots in central Wyoming, USA. Across all plots, 17% of 128 nests failed due to the hailstorm; however, all failed nests were located at a subset of study plots (n = 3) where the hailstorm was most intense, and 45% of all nests failures on those plots were due to hail. Mortality rates varied by species, nest architecture, and nest placement. Nests with more robust architecture and those sited more deeply under the shrub canopy were more likely to survive the hailstorm, suggesting that natural history traits may modulate mortality risk due to hailstorms. While sporadic in nature, hailstorms may represent a significant source of nest failure to songbirds in certain locations, especially with increasing storm frequency and severity forecasted in some regions with ongoing climate change.

  14. Rapid effects of 17β-estradiol on aggressive behavior in songbirds: Environmental and genetic influences.

    PubMed

    Heimovics, Sarah A; Merritt, Jennifer R; Jalabert, Cecilia; Ma, Chunqi; Maney, Donna L; Soma, Kiran K

    2018-04-24

    17β-estradiol (E 2 ) has numerous rapid effects on the brain and behavior. This review focuses on the rapid effects of E 2 on aggression, an important social behavior, in songbirds. First, we highlight the contributions of studies on song sparrows, which reveal that seasonal changes in the environment profoundly influence the capacity of E 2 to rapidly alter aggressive behavior. E 2 administration to male song sparrows increases aggression within 20 min in the non-breeding season, but not in the breeding season. Furthermore, E 2 rapidly modulates several phosphoproteins in the song sparrow brain. In particular, E 2 rapidly affects pCREB in the medial preoptic nucleus, in the non-breeding season only. Second, we describe studies of the white-throated sparrow, which reveal how a genetic polymorphism may influence the rapid effects of E 2 on aggression. In this species, a chromosomal rearrangement that includes ESR1, which encodes estrogen receptor α (ERα), affects ERα expression in the brain and the ability of E 2 to rapidly promote aggression. Third, we summarize studies showing that aggressive interactions rapidly affect levels of E 2 and other steroids, both in the blood and in specific brain regions, and the emerging potential for steroid profiling by liquid chromatography tandem mass spectrometry (LC-MS/MS). Such studies of songbirds demonstrate the value of an ethologically informed approach, in order to reveal how steroids act rapidly on the brain to alter naturally-occurring behavior. Copyright © 2018. Published by Elsevier Inc.

  15. Songbirds and Birds of Prey, Unit 6, Colorado Division of Wildlife.

    ERIC Educational Resources Information Center

    Hooper, Jon K.; Smith, Dwight R.

    This booklet on songbirds and birds of prey is part of a series developed to encourage youth to pursue environmental projects. The manual explains bird anatomy and physiology, bird watching, types of feeders and shelter, and bird identification. Descriptions of feeding, hunting, and nesting habits are given for many species of birds. Also,…

  16. Photoperiodic regulation of the C-repeat binding factor (CBF) cold acclimation pathway and freezing tolerance in Arabidopsis thaliana.

    PubMed

    Lee, Chin-Mei; Thomashow, Michael F

    2012-09-11

    The CBF (C-repeat binding factor) pathway has a major role in plant cold acclimation, the process whereby certain plants increase in freezing tolerance in response to low nonfreezing temperatures. In Arabidopsis thaliana, the pathway is characterized by rapid cold induction of CBF1, CBF2, and CBF3, which encode transcriptional activators, followed by induction of CBF-targeted genes that impart freezing tolerance. At warm temperatures, CBF transcript levels are low, but oscillate due to circadian regulation with peak expression occurring at 8 h after dawn (zeitgeber time 8; ZT8). Here, we establish that the CBF pathway is also regulated by photoperiod at warm temperatures. At ZT8, CBF transcript levels in short-day (SD; 8-h photoperiod) plants were three- to fivefold higher than in long-day plants (LD; 16-h photoperiod). Moreover, the freezing tolerance of SD plants was greater than that of LD plants. Genetic analysis indicated that phytochrome B (PHYB) and two phytochrome-interacting factors, PIF4 and PIF7, act to down-regulate the CBF pathway and freezing tolerance under LD conditions. Down-regulation of the CBF pathway in LD plants correlated with higher PIF4 and PIF7 transcript levels and greater stability of the PIF4 and PIF7 proteins under LD conditions. Our results indicate that during the warm LD growing season, the CBF pathway is actively repressed by PHYB, PIF4, and PIF7, thus mitigating allocation of energy and nutrient resources toward unneeded frost protection. This repression is relieved by shortening day length resulting in up-regulation of the CBF pathway and increased freezing tolerance in preparation for coming cold temperatures.

  17. Photoperiodic regulation of the C-repeat binding factor (CBF) cold acclimation pathway and freezing tolerance in Arabidopsis thaliana

    PubMed Central

    Lee, Chin-Mei; Thomashow, Michael F.

    2012-01-01

    The CBF (C-repeat binding factor) pathway has a major role in plant cold acclimation, the process whereby certain plants increase in freezing tolerance in response to low nonfreezing temperatures. In Arabidopsis thaliana, the pathway is characterized by rapid cold induction of CBF1, CBF2, and CBF3, which encode transcriptional activators, followed by induction of CBF-targeted genes that impart freezing tolerance. At warm temperatures, CBF transcript levels are low, but oscillate due to circadian regulation with peak expression occurring at 8 h after dawn (zeitgeber time 8; ZT8). Here, we establish that the CBF pathway is also regulated by photoperiod at warm temperatures. At ZT8, CBF transcript levels in short-day (SD; 8-h photoperiod) plants were three- to fivefold higher than in long-day plants (LD; 16-h photoperiod). Moreover, the freezing tolerance of SD plants was greater than that of LD plants. Genetic analysis indicated that phytochrome B (PHYB) and two phytochrome-interacting factors, PIF4 and PIF7, act to down-regulate the CBF pathway and freezing tolerance under LD conditions. Down-regulation of the CBF pathway in LD plants correlated with higher PIF4 and PIF7 transcript levels and greater stability of the PIF4 and PIF7 proteins under LD conditions. Our results indicate that during the warm LD growing season, the CBF pathway is actively repressed by PHYB, PIF4, and PIF7, thus mitigating allocation of energy and nutrient resources toward unneeded frost protection. This repression is relieved by shortening day length resulting in up-regulation of the CBF pathway and increased freezing tolerance in preparation for coming cold temperatures. PMID:22927419

  18. Elaborate visual and acoustic signals evolve independently in a large, phenotypically diverse radiation of songbirds.

    PubMed

    Mason, Nicholas A; Shultz, Allison J; Burns, Kevin J

    2014-08-07

    The concept of a macroevolutionary trade-off among sexual signals has a storied history in evolutionary biology. Theory predicts that if multiple sexual signals are costly for males to produce or maintain and females prefer a single, sexually selected trait, then an inverse correlation between sexual signal elaborations is expected among species. However, empirical evidence for what has been termed the 'transfer hypothesis' is mixed, which may reflect different selective pressures among lineages, evolutionary covariates or methodological differences among studies. Here, we examine interspecific correlations between song and plumage elaboration in a phenotypically diverse, widespread radiation of songbirds, the tanagers. The tanagers (Thraupidae) are the largest family of songbirds, representing nearly 10% of all songbirds. We assess variation in song and plumage elaboration across 301 species, representing the largest scale comparative study of multimodal sexual signalling to date. We consider whether evolutionary covariates, including habitat, structural and carotenoid-based coloration, and subfamily groupings influence the relationship between song and plumage elaboration. We find that song and plumage elaboration are uncorrelated when considering all tanagers, although the relationship between song and plumage complexity varies among subfamilies. Taken together, we find that elaborate visual and vocal sexual signals evolve independently among tanagers. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  19. Eavesdropping on the Arctic: Automated bioacoustics reveal dynamics in songbird breeding phenology

    PubMed Central

    Ellis, Daniel P. W.; Pérez, Jonathan H.; Wingfield, John C.; Boelman, Natalie T.

    2018-01-01

    Bioacoustic networks could vastly expand the coverage of wildlife monitoring to complement satellite observations of climate and vegetation. This approach would enable global-scale understanding of how climate change influences phenomena such as migratory timing of avian species. The enormous data sets that autonomous recorders typically generate demand automated analyses that remain largely undeveloped. We devised automated signal processing and machine learning approaches to estimate dates on which songbird communities arrived at arctic breeding grounds. Acoustically estimated dates agreed well with those determined via traditional surveys and were strongly related to the landscape’s snow-free dates. We found that environmental conditions heavily influenced daily variation in songbird vocal activity, especially before egg laying. Our novel approaches demonstrate that variation in avian migratory arrival can be detected autonomously. Large-scale deployment of this innovation in wildlife monitoring would enable the coverage necessary to assess and forecast changes in bird migration in the face of climate change. PMID:29938220

  20. Eavesdropping on the Arctic: Automated bioacoustics reveal dynamics in songbird breeding phenology.

    PubMed

    Oliver, Ruth Y; Ellis, Daniel P W; Chmura, Helen E; Krause, Jesse S; Pérez, Jonathan H; Sweet, Shannan K; Gough, Laura; Wingfield, John C; Boelman, Natalie T

    2018-06-01

    Bioacoustic networks could vastly expand the coverage of wildlife monitoring to complement satellite observations of climate and vegetation. This approach would enable global-scale understanding of how climate change influences phenomena such as migratory timing of avian species. The enormous data sets that autonomous recorders typically generate demand automated analyses that remain largely undeveloped. We devised automated signal processing and machine learning approaches to estimate dates on which songbird communities arrived at arctic breeding grounds. Acoustically estimated dates agreed well with those determined via traditional surveys and were strongly related to the landscape's snow-free dates. We found that environmental conditions heavily influenced daily variation in songbird vocal activity, especially before egg laying. Our novel approaches demonstrate that variation in avian migratory arrival can be detected autonomously. Large-scale deployment of this innovation in wildlife monitoring would enable the coverage necessary to assess and forecast changes in bird migration in the face of climate change.

  1. Photoperiod and aggression induce changes in ventral gland compounds exclusively in male Siberian hamsters.

    PubMed

    Rendon, Nikki M; Soini, Helena A; Scotti, Melissa-Ann L; Weigel, Ellen R; Novotny, Milos V; Demas, Gregory E

    2016-05-01

    Chemical communication is a critical component of social behavior as it facilitates social encounters, allows for evaluation of the social partner, defines territories and resources, and advertises information such as sex and physiological state of an animal. Odors provide a key source of information about the social environment to rodents; however, studies identifying chemical compounds have thus far focused primarily on few species, particularly the house mouse. Moreover, considerably less attention has been focused on how environmental factors, reproductive phenotype, and behavioral context alter these compounds outside of reproduction. We examined the effects of photoperiod, sex, and social context on chemical communication in the seasonally breeding Siberian hamster. We sampled ventral gland secretions in both male and female hamsters before and after an aggressive encounter and identified changes in a range of volatile compounds. Next, we investigated how photoperiod, reproductive phenotype, and aggression altered ventral gland volatile compound composition across the sexes. Males exhibited a more diverse chemical composition, more sex-specific volatiles, and showed higher levels of excretion compared to females. Individual volatiles were also differentially excreted across photoperiod and reproductive phenotype, as well as differentially altered in response to an aggressive encounter. Female volatile compound composition, in contrast, did not differ across photoperiods or in response to aggression. Collectively, these data contribute to a greater understanding of context-dependent changes in chemical communication in a seasonally breeding rodent. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Sleep deprivation attenuates endotoxin-induced cytokine gene expression independent of day length and circulating cortisol in male Siberian hamsters (Phodopus sungorus).

    PubMed

    Ashley, Noah T; Walton, James C; Haim, Achikam; Zhang, Ning; Prince, Laura A; Fruchey, Allison M; Lieberman, Rebecca A; Weil, Zachary M; Magalang, Ulysses J; Nelson, Randy J

    2013-07-15

    Sleep is restorative, whereas reduced sleep leads to negative health outcomes, such as increased susceptibility to disease. Sleep deprivation tends to attenuate inflammatory responses triggered by infection or exposure to endotoxin, such as bacterial lipopolysaccharide (LPS). Previous studies have demonstrated that Siberian hamsters (Phodopus sungorus), photoperiodic rodents, attenuate LPS-induced fever, sickness behavior and upstream pro-inflammatory gene expression when adapted to short day lengths. Here, we tested whether manipulation of photoperiod alters the suppressive effects of sleep deprivation upon cytokine gene expression after LPS challenge. Male Siberian hamsters were adapted to long (16 h:8 h light:dark) or short (8 h:16 h light:dark) photoperiods for >10 weeks, and were deprived of sleep for 24 h using the multiple platform method or remained in their home cage. Hamsters received an intraperitoneal injection of LPS or saline (control) 18 h after starting the protocol, and were killed 6 h later. LPS increased liver and hypothalamic interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF) gene expression compared with vehicle. Among LPS-challenged hamsters, sleep deprivation reduced IL-1 mRNA levels in liver and hypothalamus, but not TNF. IL-1 attenuation was independent of circulating baseline cortisol, which did not increase after sleep deprivation. Conversely, photoperiod altered baseline cortisol, but not pro-inflammatory gene expression in sleep-deprived hamsters. These results suggest that neither photoperiod nor glucocorticoids influence the suppressive effect of sleep deprivation upon LPS-induced inflammation.

  3. Photoperiod is the main cue that triggers supercooling ability in the land snail, Helix aspersa (Gastropoda: Helicidae).

    PubMed

    Ansart, A; Vernon, P; Daguzan, J

    2001-06-01

    Helix aspersa hibernates in Brittany (western France), where it may experience subzero temperatures. Studies on cold hardiness, although scarce in land snails, have shown a seasonal variation in supercooling ability, associated with high temperatures of crystallization (Tc). In the present work, two key environmental factors, temperature and photoperiod, were studied to elucidate, how they may affect the enhancement of supercooling ability in the snails from the end of summer to winter. Nine groups of adult snails were acclimated to different combinations of photoperiod (LD-16:8, LD-12:12, and LD-8:16 h) and temperature (15, 10, and 5 degrees C). Temperature of crystallization, hemolymph osmolality, and water content were measured. The results demonstrate a significant effect of the photoperiod on Tc, i.e., shorter photoperiods induce lower Tc (LD-16:8 h, mean Tc = -3.0 degrees C, SD = 2.0; LD-12:12 h, mean Tc = -4.3 degrees C, SD = 1.9; LD-8:16 h, mean Tc = -5.2 degrees C, SD = 1.9; n = 90), whereas the acclimation temperature had no effect. Measurements of hemolymph osmolality and water content showed that osmolality is negatively correlated with water content. Mechanisms such as dehydration are involved in the decrease of Tc. A declining photoperiod triggers a lower Tc, long before the onset of winter conditions. This response may have an adaptive component, allowing individuals to cope with the mild winters typically observed in oceanic regions. Copyright 2001 Elsevier Science.

  4. Perception of photoperiod in individual buds of mature trees regulates leaf-out.

    PubMed

    Zohner, Constantin M; Renner, Susanne S

    2015-12-01

    Experimental data on the perception of day length and temperature in dormant temperate zone trees are surprisingly scarce. In order to investigate when and where these environmental signals are perceived, we carried out bagging experiments in which buds on branches of Fagus sylvatica, Aesculus hippocastanum and Picea abies trees were exposed to natural light increase or kept at constant 8-h days from December until June. Parallel experiments used twigs cut from the same trees, harvesting treated and control twigs seven times and then exposing them to 8- or 16-h days in a glasshouse. Under 8-h days, budburst in Fagus outdoors was delayed by 41 d and in Aesculus by 4 d; in Picea, day length had no effect. Buds on nearby branches reacted autonomously, and leaf primordia only reacted to light cues in late dormancy after accumulating warm days. Experiments applying different wavelength spectra and high-resolution spectrometry to buds indicate a phytochrome-mediated photoperiod control. By demonstrating local photoperiodic control of buds, revealing the time when these signals are perceived, and showing the interplay between photoperiod and chilling, this study contributes to improved modelling of the impact of climate warming on photosensitive species. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  5. Allowable levels of take for the trade in Nearctic songbirds.

    PubMed

    Johnson, Fred A; Walters, Matthew A H; Boomer, G Scott

    2012-06-01

    The take of Nearctic songbirds for the caged-bird trade is an important cultural and economic activity in Mexico, but its sustainability has been questioned. We relied on the theta-logistic population model to explore options for setting allowable levels of take for 11 species of passerines that were subject to legal take in Mexico in 2010. Because estimates of population size necessary for making-periodic adjustments to levels of take are not routinely available, we examined the conditions under which a constant level of take might contribute to population depletion (i.e., a population below its level of maximum net productivity). The chance of depleting a population is highest when levels of take are based on population sizes that happen to be much lower or higher than the level of maximum net productivity, when environmental variation is relatively high and serially correlated, and when the interval between estimation of population size is relatively long (> or = 5 years). To estimate demographic rates of songbirds involved in the Mexican trade we relied on published information and allometric relationships to develop probability distributions for key rates, and then sampled from those distributions to characterize the uncertainty in potential levels of take. Estimates of the intrinsic rate of growth (r) were highly variable, but median estimates were consistent with those expected for relatively short-lived, highly fecund species. Allowing for the possibility of nonlinear density dependence generally resulted in allowable levels of take that were lower than would have been the case under an assumption of linearity. Levels of take authorized by the Mexican government in 2010 for the 11 species we examined were small in comparison to relatively conservative allowable levels of take (i.e., those intended to achieve 50% of maximum sustainable yield). However, the actual levels of take in Mexico are unknown and almost certainly exceed the authorized take. Also, the

  6. Allowable levels of take for the trade in Nearctic songbirds

    USGS Publications Warehouse

    Johnson, Fred A.; Walters, Matthew A.H.; Boomer, G. Scott

    2012-01-01

    The take of Nearctic songbirds for the caged-bird trade is an important cultural and economic activity in Mexico, but its sustainability has been questioned. We relied on the theta-logistic population model to explore options for setting allowable levels of take for 11 species of passerines that were subject to legal take in Mexico in 2010. Because estimates of population size necessary for making periodic adjustments to levels of take are not routinely available, we examined the conditions under which a constant level of take might contribute to population depletion (i.e., a population below its level of maximum net productivity). The chance of depleting a population is highest when levels of take are based on population sizes that happen to be much lower or higher than the level of maximum net productivity, when environmental variation is relatively high and serially correlated, and when the interval between estimation of population size is relatively long (≥5 years). To estimate demographic rates of songbirds involved in the Mexican trade we relied on published information and allometric relationships to develop probability distributions for key rates, and then sampled from those distributions to characterize the uncertainty in potential levels of take. Estimates of the intrinsic rate of growth (r) were highly variable, but median estimates were consistent with those expected for relatively short-lived, highly fecund species. Allowing for the possibility of nonlinear density dependence generally resulted in allowable levels of take that were lower than would have been the case under an assumption of linearity. Levels of take authorized by the Mexican government in 2010 for the 11 species we examined were small in comparison to relatively conservative allowable levels of take (i.e., those intended to achieve 50% of maximum sustainable yield). However, the actual levels of take in Mexico are unknown and almost certainly exceed the authorized take. Also, the take

  7. Sweetgum Dormancy Release: Effects of Chilling, Photoperiod, and Genotype

    Treesearch

    Robert E. Farmer

    1968-01-01

    In L., 1200 to 1600 hours of chilling (3 D C) resulted in rapid resumption of growth under greenhouse forcing conditions. Long photoperiods were effective substitutes for chilling. Plants from southern Alabama (Lat. 31°) had a lower chilling requirement than those from western Tennessee (Lat. 36°). Growth rate of plants under...

  8. Patterns of Nucleotide Diversity at Photoperiod Related Genes in Norway Spruce [Picea abies (L.) Karst.

    PubMed Central

    Källman, Thomas; De Mita, Stéphane; Larsson, Hanna; Gyllenstrand, Niclas; Heuertz, Myriam; Parducci, Laura; Suyama, Yoshihisa; Lagercrantz, Ulf; Lascoux, Martin

    2014-01-01

    The ability of plants to track seasonal changes is largely dependent on genes assigned to the photoperiod pathway, and variation in those genes is thereby important for adaptation to local day length conditions. Extensive physiological data in several temperate conifer species suggest that populations are adapted to local light conditions, but data on the genes underlying this adaptation are more limited. Here we present nucleotide diversity data from 19 genes putatively involved in photoperiodic response in Norway spruce (Picea abies). Based on similarity to model plants the genes were grouped into three categories according to their presumed position in the photoperiod pathway: photoreceptors, circadian clock genes, and downstream targets. An HKA (Hudson, Kreitman and Aquade) test showed a significant excess of diversity at photoreceptor genes, but no departure from neutrality at circadian genes and downstream targets. Departures from neutrality were also tested with Tajima's D and Fay and Wu's H statistics under three demographic scenarios: the standard neutral model, a population expansion model, and a more complex population split model. Only one gene, the circadian clock gene PaPRR3 with a highly positive Tajima's D value, deviates significantly from all tested demographic scenarios. As the PaPRR3 gene harbours multiple non-synonymous variants it appears as an excellent candidate gene for control of photoperiod response in Norway spruce. PMID:24810273

  9. Patterns of nucleotide diversity at photoperiod related genes in Norway spruce [Picea abies (L.) Karst].

    PubMed

    Källman, Thomas; De Mita, Stéphane; Larsson, Hanna; Gyllenstrand, Niclas; Heuertz, Myriam; Parducci, Laura; Suyama, Yoshihisa; Lagercrantz, Ulf; Lascoux, Martin

    2014-01-01

    The ability of plants to track seasonal changes is largely dependent on genes assigned to the photoperiod pathway, and variation in those genes is thereby important for adaptation to local day length conditions. Extensive physiological data in several temperate conifer species suggest that populations are adapted to local light conditions, but data on the genes underlying this adaptation are more limited. Here we present nucleotide diversity data from 19 genes putatively involved in photoperiodic response in Norway spruce (Picea abies). Based on similarity to model plants the genes were grouped into three categories according to their presumed position in the photoperiod pathway: photoreceptors, circadian clock genes, and downstream targets. An HKA (Hudson, Kreitman and Aquade) test showed a significant excess of diversity at photoreceptor genes, but no departure from neutrality at circadian genes and downstream targets. Departures from neutrality were also tested with Tajima's D and Fay and Wu's H statistics under three demographic scenarios: the standard neutral model, a population expansion model, and a more complex population split model. Only one gene, the circadian clock gene PaPRR3 with a highly positive Tajima's D value, deviates significantly from all tested demographic scenarios. As the PaPRR3 gene harbours multiple non-synonymous variants it appears as an excellent candidate gene for control of photoperiod response in Norway spruce.

  10. Adaptation to short photoperiods augments circadian food anticipatory activity in Siberian hamsters.

    PubMed

    Bradley, Sean P; Prendergast, Brian J

    2014-06-01

    This article is part of a Special Issue "Energy Balance". Both the light-dark cycle and the timing of food intake can entrain circadian rhythms. Entrainment to food is mediated by a food entrainable circadian oscillator (FEO) that is formally and mechanistically separable from the hypothalamic light-entrainable oscillator. This experiment examined whether seasonal changes in day length affect the function of the FEO in male Siberian hamsters (Phodopus sungorus). Hamsters housed in long (LD; 15 h light/day) or short (SD; 9h light/day) photoperiods were subjected to a timed-feeding schedule for 10 days, during which food was available only during a 5h interval of the light phase. Running wheel activity occurring within a 3h window immediately prior to actual or anticipated food delivery was operationally-defined as food anticipatory activity (FAA). After the timed-feeding interval, hamsters were fed ad libitum, and FAA was assessed 2 and 7 days later via probe trials of total food deprivation. During timed-feeding, all hamsters exhibited increases FAA, but FAA emerged more rapidly in SD; in probe trials, FAA was greater in magnitude and persistence in SD. Gonadectomy in LD did not induce the SD-like FAA phenotype, indicating that withdrawal of gonadal hormones is not sufficient to mediate the effects of photoperiod on FAA. Entrainment of the circadian system to light markedly affects the functional output of the FEO via gonadal hormone-independent mechanisms. Rapid emergence and persistent expression of FAA in SD may reflect a seasonal adaptation that directs behavior toward sources of nutrition with high temporal precision at times of year when food is scarce. © 2013.

  11. A comparative analysis of auditory perception in humans and songbirds: a modular approach.

    PubMed

    Weisman, Ronald; Hoeschele, Marisa; Sturdy, Christopher B

    2014-05-01

    We propose that a relatively small number of perceptual skills underlie human perception of music and speech. Humans and songbirds share a number of features in the development of their auditory communication systems. These similarities invite comparisons between species in their auditory perceptual skills. Here, we summarized our experimental comparisons between humans (and other mammals) and songbirds (and other birds) in their use of pitch height and pitch chroma perception and discuss similarities and differences in other auditory perceptual abilities of these species. Specifically, we introduced a functional modular view, using pitch chroma and pitch height perception as examples, as a theoretical framework for the comparative study of auditory perception and perhaps all of the study of comparative cognition. We also contrasted phylogeny and adaptation as causal mechanisms in comparative cognition using examples from auditory perception. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Heading date QTL in winter wheat (Triticum aestivum L.) coincide with major developmental genes Vernalization-1 and Photoperiod-1

    USDA-ARS?s Scientific Manuscript database

    In wheat (Triticum aestivum L.), time from planting to spike emergence is influenced by genes controlling vernalization requirement and photoperiod response. Characterizing the available genetic diversity of known and novel alleles of Vernalization-1 (Vrn-1) and Photoperiod-1 (Ppd-1) in winter wheat...

  13. Seasonal Patterns in Eastern Equine Encephalitis Virus Antibody in Songbirds in Southern Maine.

    PubMed

    Elias, Susan P; Keenan, Patrick; Kenney, Joan L; Morris, Sara R; Covino, Kristen M; Robinson, Sara; Foss, Kimberly A; Rand, Peter W; Lubelczyk, Charles; Lacombe, Eleanor H; Mutebi, John-Paul; Evers, David; Smith, Robert P

    2017-05-01

    The intent of this study was to assess passerine eastern equine encephalitis virus (EEEv) seroprevalence during the breeding season in southern Maine by testing songbird species identified in the literature as amplifying hosts of this virus. In 2013 and 2014, we collected serum samples from songbirds at a mainland site and an offshore island migratory stopover site, and screened samples for EEEv antibodies using plaque reduction neutralization tests. We compared seasonal changes in EEEv antibody seroprevalence in young (hatched in year of capture) and adult birds at the mainland site, and also compared early season seroprevalence in mainland versus offshore adult birds. EEEv seroprevalence did not differ significantly between years at either site. During the early season (May), EEEv antibody seroprevalence was substantially lower (9.6%) in the island migrant adults than in mainland adults (42.9%), 2013-2014. On the mainland, EEEv antibody seroprevalence in young birds increased from 12.9% in midseason (June-August) to 45.6% in late season (September/October), 2013-2014. Seroprevalence in adult birds did not differ between seasons (48.8% vs. 53.3%). EEEv activity in Maine has increased in the past decade as measured by increased virus detection in mosquitoes and veterinary cases. High EEEv seroprevalence in young birds-as compared to that of young birds in other studies-corresponded with two consecutive active EEEv years in Maine. We suggest that young, locally hatched songbirds be sampled as a part of long-term EEEv surveillance, and provide a list of suggested species to sample, including EEEv "superspreaders."

  14. Attitudes of Vermont dairy farmers regarding adoption of management practices for grassland songbirds

    USGS Publications Warehouse

    Troy, A.B.; Strong, A.M.; Bosworth, S.C.; Donovan, T.M.; Buckley, N.J.; Wilson, M.L.

    2005-01-01

    In the northeastern United States, most populations of grassland songbirds occur on private lands. However, little information exists about the attitudes of farmers toward habitat management for this guild. To address this information gap, we surveyed 131 dairy farmers in Vermont's Champlain Valley to assess current hayfield management practices and farmers' willingness to adopt more "bird-friendly" practices. Our results showed a clear trend toward earlier and more frequent hayfield cuts. Farmers indicated they have little flexibility to alter the timing of their cuts on most of their land. However, many farmers (49%) indicated a willingness to adopt alternative management practices on at least a small portion of their land. Combined with the fact that many farmers characterized parts of their land as "wasteland," or economically unproductive land, this result suggests that some leeway exists for increasing songbird habitat quality on at least portions of dairy farms. Although significant differences existed in the amount of land for which farmers were willing to adopt alternative management based on herd size, acreage, and experience, the directionality of these relationships could not be established except tentatively for herd size, in which case it appeared that farmers with smaller herds were more likely to dedicate a greater percentage of their land to alternative management. The results of this study likely have relevance to dairy farms throughout the northern-tier dairy states. Given the increasing trend for agricultural land to be converted into housing, we recommend that extension and education efforts target farmers with large hayfield acreages, encouraging the maintenance of high-quality habitat for grassland songbirds.

  15. Social and photoperiod effects on reproduction in five species of Peromyscus.

    PubMed

    Trainor, Brian C; Martin, Lynn B; Greiwe, Kelly M; Kuhlman, Joshua R; Nelson, Randy J

    2006-09-01

    At temperate latitudes, mammals and birds use changes in day length to time their reproductive activities to coincide with seasonal fluctuations in the environment. Close to the equator, however, conditions permissive of breeding do not track changes in day length as well, so other cues may be more important than photoperiod. In a variety of vertebrates, social interactions regulate breeding condition. We hypothesized that individuals of different species of Peromyscus mice found closer to the equator would respond more strongly to housing with an opposite sex conspecific than they would to photoperiod. To test this hypothesis, we compared the effects of long and short day lengths versus 8 days of pair housing with a female on reproductive tissue weights and testosterone (T) concentrations in five species of Peromyscus (P. aztecus, P. eremicus, P. maniculatus, P. melanophrys, and P. polionotus). After 13 weeks of short days (8L:16D), P. maniculatus, P. melanophrys, and P. polionotus significantly reduced relative testes mass compared to long day (16L:8D) housed animals. Social housing, however, had no effect on tissue weights in any species. However, male P. polionotus paired with females for 8 days increased T concentrations compared to single-housed males, whereas paired P. maniculatus reduced T. These data suggest that mechanisms of photoperiodic and social regulation of reproductive function are mediated by different physiological mechanisms among closely-related species and that both phylogeny and environmental factors contribute to patterns of reproductive plasticity.

  16. Geographic Variation of Diapause and Sensitive Stages of Photoperiodic Response in Laodelphax striatellus Fallén (Hemiptera: Delphacidae)

    PubMed Central

    Hou, Yang-Yang; Xu, Lan-Zhen; Wu, Yan; Wang, Peng; Shi, Jin-Jian; Zhai, Bao-Ping

    2016-01-01

    Large numbers of the small brown planthopper Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae) occur in temperate regions, causing severe losses in rice, wheat, and other economically important crops. The planthoppers enter diapause in the third- or fourth-instar nymph stage, induced by short photoperiods and low temperatures. To investigate the geographic variation in L. striatellus diapause, we compared the incidence of nymphal diapause under various constant temperature (20 and 27°C) and a photoperiod of 4:20, 8:16, 10:14, 12:12, 14:10, and 16:8 (L:D) h regimes among three populations collected from Hanoi (21.02° N, 105.85° E, northern Vietnam), Jiangyan (32.51° N, 120.15° E, eastern China), and Changchun (43.89° N, 125.32° E, north-eastern China). Our results indicated that there were significant geographic variations in the diapause of L. striatellus. When the original latitude of the populations increased, higher diapause incidence and longer critical photoperiod (CP) were exhibited. The CPs of the Jiangyan and Changchun populations were ∼12 hr 30 min and 13 hr at 20°C, and 11 hr and 11 hr 20 min at 27°C, respectively. The second- and third-instar nymphs were at the stage most sensitive to the photoperiod. However, when the fourth- and fifth-instar nymphs were transferred to a long photoperiod, the diapause-inducing effect of the short photoperiod on young instars was almost reversed. The considerable geographic variations in the nymphal diapause of L. striatellus reflect their adaptation in response to a variable environment and provide insights to develop effective pest management strategies. PMID:26839318

  17. Geographic Variation of Diapause and Sensitive Stages of Photoperiodic Response in Laodelphax striatellus Fallén (Hemiptera: Delphacidae).

    PubMed

    Hou, Yang-Yang; Xu, Lan-Zhen; Wu, Yan; Wang, Peng; Shi, Jin-Jian; Zhai, Bao-Ping

    2016-01-01

    Large numbers of the small brown planthopper Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae) occur in temperate regions, causing severe losses in rice, wheat, and other economically important crops. The planthoppers enter diapause in the third- or fourth-instar nymph stage, induced by short photoperiods and low temperatures. To investigate the geographic variation in L. striatellus diapause, we compared the incidence of nymphal diapause under various constant temperature (20 and 27 °C) and a photoperiod of 4:20, 8:16, 10:14, 12:12, 14:10, and 16:8 (L:D) h regimes among three populations collected from Hanoi (21.02° N, 105.85° E, northern Vietnam), Jiangyan (32.51° N, 120.15° E, eastern China), and Changchun (43.89° N, 125.32° E, north-eastern China). Our results indicated that there were significant geographic variations in the diapause of L. striatellus. When the original latitude of the populations increased, higher diapause incidence and longer critical photoperiod (CP) were exhibited. The CPs of the Jiangyan and Changchun populations were ∼ 12 hr 30 min and 13 hr at 20 °C, and 11 hr and 11 hr 20 min at 27 °C, respectively. The second- and third-instar nymphs were at the stage most sensitive to the photoperiod. However, when the fourth- and fifth-instar nymphs were transferred to a long photoperiod, the diapause-inducing effect of the short photoperiod on young instars was almost reversed. The considerable geographic variations in the nymphal diapause of L. striatellus reflect their adaptation in response to a variable environment and provide insights to develop effective pest management strategies. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

  18. Regulation of vernal migration in Gambel's white-crowned sparrows: Role of thyroxine and triiodothyronine.

    PubMed

    Pérez, Jonathan H; Furlow, J David; Wingfield, John C; Ramenofsky, Marilyn

    2016-08-01

    Appropriate timing of migratory behavior is critical for migrant species. For many temperate zone birds in the spring, lengthening photoperiod is the initial cue leading to morphological, physiological and behavior changes that are necessary for vernal migration and breeding. Strong evidence has emerged in recent years linking thyroid hormone signaling to the photoinduction of breeding in birds while more limited information suggest a potential role in the regulation of vernal migration in photoperiodic songbirds. Here we investigate the development and expression of the vernal migratory life history stage in captive Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) in a hypothyroidic state, induced by chemical inhibition of thyroid hormone production. To explore possible variations in the effects of the two thyroid hormones, triiodothyronine and thyroxine, we subsequently performed a thyroid inhibition coupled with replacement therapy. We found that chemical inhibition of thyroid hormones resulted in complete abolishment of mass gain, fattening, and muscle hypertrophy associated with migratory preparation as well as resulting in failure to display nocturnal restlessness behavior. Replacement of thyroxine rescued all of these elements to near control levels while triiodothyronine replacement displayed partial or delayed rescue. Our findings support thyroid hormones as being necessary for the expression of changes in morphology and physiology associated with migration as well as migratory behavior itself. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Latitudinal variation in photoperiodic response of the three-spined stickleback Gasterosteus aculeatus in western North America

    PubMed Central

    Yeates-Burghart, Q. S.; O’Brien, C.; Cresko, W. A.; Holzapfel, C. M.; Bradshaw, W. E.

    2014-01-01

    Reproductive maturation in both male and female three-spined stickleback Gasterosteus aculeatus was strongly photoperiodic in a northern population (Alaska, 61° N) but not in a southern population (Oregon, 43° N) from western North America. Increasing reliance on photoperiod with increasing latitude is a general phenomenon among vertebrates, and is probably due to the anticipation of a narrower window of opportunity for reproduction and development at higher latitudes. PMID:20738673

  20. Annual gonadal cycles in birds: modeling the effects of photoperiod on seasonal changes in GnRH-1 secretion.

    PubMed

    Dawson, Alistair

    2015-04-01

    This paper reviews current knowledge of photoperiod control of GnRH-1 secretion and proposes a model in which two processes act together to regulate GnRH1 secretion. Photo-induction controls GnRH1 secretion and is directly related to prevailing photoperiod. Photo-inhibition, a longer term process, acts through GnRH1 synthesis. It progresses each day during daylight hours, but reverses during darkness. Thus, photo-inhibition gradually increases when photoperiods exceed 12h, and reverses under shorter photoperiods. GnRH1 secretion on any particular day is the net result of these two processes acting in tandem. The only difference between species is their sensitivity to photo-inhibition. This can potentially explain differences in timing and duration of breeding seasons between species, why some species become absolutely photorefractory and others relatively photorefractory, why breeding seasons end at the same time at different latitudes within species, and why experimental protocols sometimes produce results that appear counter to what happens naturally. Copyright © 2014 The Author. Published by Elsevier Inc. All rights reserved.

  1. Effects of temperature and photoperiod on postponing bermudagrass (Cynodon dactylon [L.] Pers.) turf dormancy.

    PubMed

    Esmaili, Somayeh; Salehi, Hassan

    2012-06-15

    Growth chamber and field experiments were carried out to determine the effects of extended photoperiod under low and freezing temperatures on bermudagrass turf dormancy at Bajgah, in the southern part of Iran. The experiment in the growth chamber was conducted with four temperature regimes (15, 7.5, 0 and -7.5°C) and three light durations (8, 12 and 16h) in a completely randomized design with four replications. The field study was conducted in two consecutive years (2008-2009) with three light durations (8, 12 and 16h) in months with natural short day length and arranged in a randomized complete blocks design with three replications. Results in both experiments showed that decreasing temperature and photoperiod decreased verdure fresh and dry weight, shoot height, tiller density, leaf area and chlorophyll and relative water contents (RWC). However, rooting depth and fresh weight of roots increased in the growth chamber. Decreasing the temperature and light duration increased electrolyte leakage and proline content. Reducing sugars increased with decreasing temperature and declined with lowering light duration in both shoots and roots. Starch content of both shoots and roots showed an adverse trend compared to reducing sugars; starch content increased in both shoots and roots in all treatments by shortening the photoperiod. Practically, the problem of bermudagrass turf's dormancy could be solved via increasing the photoperiod in months with short day lengths. This treatment would be efficient and useful for turfgrass managers to apply in landscapes and stadiums. Copyright © 2012 Elsevier GmbH. All rights reserved.

  2. Interactive effects of photoperiod and light intensity on blood physiological and biochemical reactions of broilers grown to heavy weights.

    PubMed

    Olanrewaju, H A; Purswell, J L; Collier, S D; Branton, S L

    2013-04-01

    The effects of photoperiod, light intensity, and their interaction on blood acid-base balance, metabolites, and electrolytes in broiler chickens under environmentally controlled conditions were examined in 2 trials. A 3 × 3 factorial experiment in a randomized complete block design was used in this study. In each trial, all treatment groups were provided 23L:1D with 20 lx of intensity from placement to 7 d, and then subjected to the treatments. The 9 treatments consisted of 3 photoperiods [long/continuous (23L:1D) from d 8 to 56, regular/intermittent (2L:2D), and short/nonintermittent (8L:16D) from d 8 to 48 and 23L:1D from d 49 to 56, respectively] and exposure to 3 light intensities (10, 5.0, and 0.5 lx) from d 8 through d 56 at 50% RH. Feed and water were provided ad libitum. Venous blood samples were collected on d 7, 14, 28, 42, and 56. Main effects indicated that short/nonintermittent photoperiod significantly (P < 0.05) reduced BW, pH, partial pressure of O2, saturated O2, Na(+), K(+), Ca(2+), Cl(-), osmolality, triiodothyronine (T3), and total protein along with significantly (P < 0.05) elevated partial pressure of CO2, hematocrit, hemoglobin, and lactate concentrations. In addition, there were no effects of photoperiod on HCO3(-), glucose, anion gap, and thyroxine (T4). Plasma corticosterone was not affected by photoperiod, light intensity, or their interaction. There was no effect of light intensity on most of the blood variables examined. Acid-base regulation during photoperiod and light intensity exposure did not deteriorate despite a lower pH and higher partial pressure of CO2 with normal HCO3(-). These results indicate that continuous exposure of broiler chickens to varying light intensities had a minor effect on blood physiological variables, whereas the short photoperiod markedly affected most blood physiological variables without inducing physiological stress in broilers.

  3. Importance of photoperiods in determining temporal pattern of annual testicular events in rose-ringed parakeet (Psittacula krameri).

    PubMed

    Maitra, S K; Dey, M

    1992-01-01

    Male rose-ringed parakeets (Psittacula krameri) were transferred to a long photoperiod (LP; LD 16:8) or a short photoperiod (SP; LD 8:16) for 45 or 90 days on four dates corresponding to the beginnings of different reproductive phases in an annual testicular cycle, and testicular responsiveness was evaluated by comparison with the testicular volume, weight, seminiferous tubular diameter, and germ cell profiles of birds in a natural photoperiod (NP). Exposure of birds to LP during the progressive phase (November) led to precocious maturation of testes after 45 days, but induced regression at 90 days. After showing retarded gametogenic functions at 45 days, parallel (November) SP birds exhibited an accelerated rate of germ cell formation at day 90. During the prebreeding phase (January), there were no remarkable differences in any features of testes among NP. LP, and SP birds at 45 days, but gonadal involution in LP parakeets and active spermatogenesis in SP birds occurred after 90 days. The testes did not show any response to LP or SP for 45 and 90 days when the birds were transferred to altered photoperiods during the breeding (March) and preparatory (June) phases, indicating that the parakeets were photorefractory for at least 6 months (March through September). The results also suggest that initiation and termination of seasonal gametogenic activity in parakeets are possibly functions of endogenous rhythmicity or extraphotoperiodic environmental factors. Duration of light may have certain influences on the attainment of annual peak in spermatogenesis, but in all probability the species has a low photoperiod threshold for induction of testicular growth.

  4. The influence of temperature and photoperiod on the timing of brood onset in hibernating honey bee colonies

    PubMed Central

    Härtel, Stephan; Steffan-Dewenter, Ingolf

    2018-01-01

    In order to save resources, honey bee (Apis mellifera) colonies in the temperate zones stop brood rearing during winter. Brood rearing is resumed in late winter to build up a sufficient worker force that allows to exploit floral resources in upcoming spring. The timing of brood onset in hibernating colonies is crucial and a premature brood onset could lead to an early depletion of energy reservoirs. However, the mechanisms underlying the timing of brood onset and potential risks of mistiming in the course of ongoing climate change are not well understood. To assess the relative importance of ambient temperature and photoperiod as potential regulating factors for brood rearing activity in hibernating colonies, we overwintered 24 honey bee colonies within environmental chambers. The colonies were assigned to two different temperature treatments and three different photoperiod treatments to disentangle the individual and interacting effects of temperature and photoperiod. Tracking in-hive temperature as indicator for brood rearing activity revealed that increasing ambient temperature triggered brood onset. Under cold conditions, photoperiod alone did not affect brood onset, but the light regime altered the impact of higher ambient temperature on brood rearing activity. Further the number of brood rearing colonies increased with elapsed time which suggests the involvement of an internal clock. We conclude that timing of brood onset in late winter is mainly driven by temperature but modulated by photoperiod. Climate warming might change the interplay of these factors and result in mismatches of brood phenology and environmental conditions. PMID:29844964

  5. LIFE HISTORY. Age-related mortality explains life history strategies of tropical and temperate songbirds.

    PubMed

    Martin, Thomas E

    2015-08-28

    Life history theory attempts to explain why species differ in offspring number and quality, growth rate, and parental effort. I show that unappreciated interactions of these traits in response to age-related mortality risk challenge traditional perspectives and explain life history evolution in songbirds. Counter to a long-standing paradigm, tropical songbirds grow at similar overall rates to temperate species but grow wings relatively faster. These growth tactics are favored by predation risk, both in and after leaving the nest, and are facilitated by greater provisioning of individual offspring by parents. Increased provisioning of individual offspring depends on partitioning effort among fewer young because of constraints on effort from adult and nest mortality. These growth and provisioning responses to mortality risk finally explain the conundrum of small clutch sizes of tropical birds. Copyright © 2015, American Association for the Advancement of Science.

  6. Effects of bridge construction on songbirds and small mammals at Blennerhassett Island, Ohio River, USA.

    PubMed

    Vance, Joshua A; Angus, Norse B; Anderson, James T

    2013-09-01

    Construction of man-made objects such as roads and bridges may have impacts on wildlife depending on species or location. We investigated songbirds and small mammals along the Ohio River, WV, USA at a new bridge both before and after construction and at a bridge crossing that was present throughout the study. Comparisons were made at each site over three time periods (1985-1987 [Phase I] and 1998-2000 [Phase II] [pre-construction], 2007-2009 [Phase III] [post-construction]) and at three distances (0, 100, 300 m) from the bridge or proposed bridge location. Overall, 70 songbirds and 10 small mammals were detected during the study. Cliff swallows (Petrochelidon pyrrhonota) and rock pigeons (Columba livia) showed high affinity for bridges (P < 0.05). Combined small mammal abundances increased between Phases I and II (P < 0.05), but did not differ between Phases II and III (P > 0.05). Species richness and diversity for songbirds and small mammals did not differ before and after bridge construction (P > 0.05). We found that most species sampled did not respond to the bridge crossing, and believe that the bridge is not causing any measurable negative density impacts to the species we investigated. The new bridge does provide habitat for exotic rock pigeons that are adjusted to man-made structures for nesting.

  7. Hg-contaminated terrestrial spiders pose a potential risk to songbirds at Caddo Lake (Texas/Louisiana, USA).

    PubMed

    Gann, Gretchen L; Powell, Cleveland H; Chumchal, Matthew M; Drenner, Ray W

    2015-02-01

    Methylmercury (MeHg) is an environmental contaminant that can have adverse effects on wildlife. Because MeHg is produced by bacteria in aquatic ecosystems, studies of MeHg contamination of food webs historically have focused on aquatic organisms. However, recent studies have shown that terrestrial organisms such as songbirds can be contaminated with MeHg by feeding on MeHg-contaminated spiders. In the present study, the authors examined the risk that MeHg-contaminated terrestrial long-jawed orb weaver spiders (Tetragnatha sp.) pose to songbirds at Caddo Lake (Texas/Louisiana, USA). Methylmercury concentrations in spiders were significantly different in river, wetland, and open-water habitats. The authors calculated spider-based wildlife values (the minimum spider MeHg concentrations causing physiologically significant doses in consumers) to assess exposure risks for arachnivorous birds. Methylmercury concentrations in spiders exceeded wildlife values for Carolina chickadee (Poecile carolinensis) nestlings, with the highest risk in the river habitat. The present study indicates that MeHg concentrations in terrestrial spiders vary with habitat and can pose a threat to small-bodied nestling birds that consume large amounts of spiders at Caddo Lake. This MeHg threat to songbirds may not be unique to Caddo Lake and may extend throughout the southeastern United States. © 2014 SETAC.

  8. Photoperiodic control of sugar release during the floral transition: What is the role of sugars in the florigenic signal?

    PubMed

    Ortiz-Marchena, M Isabel; Romero, José M; Valverde, Federico

    2015-01-01

    Florigen is a mobile signal released by the leaves that reaching the shoot apical meristem (SAM), changes its developmental program from vegetative to reproductive. The protein FLOWERING LOCUS T (FT) constitutes an important element of the florigen, but other components such as sugars, have been also proposed to be part of this signal. (1-5) We have studied the accumulation and composition of starch during the floral transition in Arabidopsis thaliana in order to understand the role of carbon mobilization in this process. In A. thaliana and Antirrhinum majus the gene coding for the Granule-Bound Starch Synthase (GBSS) is regulated by the circadian clock (6,7) while in the green alga Chlamydomonas reinhardtii the homolog gene CrGBSS is controlled by photoperiod and circadian signals. (8,9) In a recent paper(10) we described the role of the central photoperiodic factor CONSTANS (CO) in the regulation of GBSS expression in Arabidopsis. This regulation is in the basis of the change in the balance between starch and free sugars observed during the floral transition. We propose that this regulation may contribute to the florigenic signal and to the increase in sugar transport required during the flowering process.

  9. Movement of feeder-using songbirds: the influence of urban features.

    PubMed

    Cox, Daniel T C; Inger, Richard; Hancock, Steven; Anderson, Karen; Gaston, Kevin J

    2016-11-23

    Private gardens provide vital opportunities for people to interact with nature. The most popular form of interaction is through garden bird feeding. Understanding how landscape features and seasons determine patterns of movement of feeder-using songbirds is key to maximising the well-being benefits they provide. To determine these patterns we established three networks of automated data loggers along a gradient of greenspace fragmentation. Over a 12-month period we tracked 452 tagged blue tits Cyantistes caeruleus and great tits Parus major moving between feeder pairs 9,848 times, to address two questions: (i) Do urban features within different forms, and season, influence structural (presence-absence of connections between feeders by birds) and functional (frequency of these connections) connectivity? (ii) Are there general patterns of structural and functional connectivity across forms? Vegetation cover increased connectivity in all three networks, whereas the presence of road gaps negatively affected functional but not structural connectivity. Across networks structural connectivity was lowest in the summer when birds maintain breeding territories, however patterns of functional connectivity appeared to vary with habitat fragmentation. Using empirical data this study shows how key urban features and season influence movement of feeder-using songbirds, and we provide evidence that this is related to greenspace fragmentation.

  10. Song practice as a rewarding form of play in songbirds.

    PubMed

    Riters, Lauren V; Spool, Jeremy A; Merullo, Devin P; Hahn, Allison H

    2017-10-12

    In adult songbirds, the primary functions of song are mate attraction and territory defense; yet, many songbirds sing at high rates as juveniles and outside these primary contexts as adults. Singing outside primary contexts is critical for song learning and maintenance, and ultimately necessary for breeding success. However, this type of singing (i.e., song "practice") occurs even in the absence of immediate or obvious extrinsic reinforcement; that is, it does not attract mates or repel competitors. Here we review studies that support the hypothesis that song practice is stimulated and maintained by intrinsic reward mechanisms (i.e., that it is associated with a positive affective state). Additionally, we propose that song practice can be considered a rewarding form of play behavior similar to forms of play observed in multiple young animals as they practice sequences of motor events that are used later in primary adult reproductive contexts. This review highlights research suggesting at least partially overlapping roles for neural reward systems in birdsong and mammalian play and evidence that steroid hormones modify these systems to shift animals from periods of intrinsically rewarded motor exploration (i.e., singing in birds and play in mammals) to the use of similar motor patterns in primary reproductive contexts. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Effects of changes in photoperiod and temperature on the estrous cycle of a captive female giant panda (Ailuropoda melanoleuca).

    PubMed

    Tay, Trisha T N; Li, Desheng; Huang, Yan; Wang, Pengyan; Tahar, Tasha; Kawi, Josephine

    2018-03-01

    The female giant panda's estrus is known to be photoperiod sensitive, triggered by increasing day length. A pair of giant pandas was brought to Singapore in September 2012 and exposed to a constant temperature and photoperiod during the first 2 years. The female did not show any signs of estrus during that period. In November 2014, photoperiod and temperature were manipulated to simulate seasonal changes, to investigate the effects of environmental factors on the sexual behavior of the giant pandas. This paper documents the changes and observations carried out from 2012 to 2016, in the attempt to breed this vulnerable species. © 2018 Wiley Periodicals, Inc.

  12. Effects of short photoperiod on energy intake, thermogenesis, and reproduction in desert hamsters (Phodopus roborovskii).

    PubMed

    Zhang, Xueying; Zhao, Zhijun; Vasilieva, Nina; Khrushchova, Anastasia; Wang, Dehua

    2015-03-01

    Desert hamsters (Phodopus roborovskii) are the least known species in the genus Phodopus with respect to ecology and physiology, and deserve scientific attention, particularly because of their small body size. Here, the responses of energy metabolism and reproductive function to short photoperiods in desert hamsters were investigated. Male and female desert hamsters were acclimated to either long day (LD) (L:D 16:8 h) or short day (SD) photoperiods (L:D 8:16 h) for three months, and then the females were transferred back to an LD photoperiod for a further five months, while at the end of the SD acclimation the males were killed and measurements were taken for serum leptin as well as molecular markers for thermogenesis. We found that like the other two species from the genus Phodopus, the desert hamsters under SD decreased body mass, increased adaptive thermogenesis as indicated by elevated mitochondrial protein content and uncoupling protein-1 content in brown adipose tissue, and suppressed reproduction compared to those under LD. However, different from the other two species, desert hamsters did not show any differences in energy intake or serum leptin concentration between LD and SD. These data suggest that different species from the same genus respond in different ways to the environmental signals, and the desert adapted species are not as sensitive to change in photoperiod as the other two species. © 2014 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

  13. Assessment of anoxia tolerance and photoperiod dependence of GABAergic polarity in the pond snail Lymnaea stagnalis.

    PubMed

    Buck, Leslie T; Bond, Hilary C; Malik, Aqsa

    2017-01-01

    The pond snail Lymnaea stagnalis is reported to be anoxia-tolerant and if the tolerance mechanism is similar to that of the anoxia-tolerant painted turtle, GABA should play an important role. A potentially confounding factor investigating the role of GABA in anoxia tolerance are reports that GABA has both inhibitory and excitatory effects within L. stagnalis central ganglion. We therefore set out to determine if seasonality or photoperiod has an impact on: 1) the anoxia-tolerance of the intact pond snail, and 2) the response of isolated neuroganglia cluster F neurons to exogenous GABA application. L. stagnalis maintained on a natural summer light cycle were unable to survive any period of anoxic exposure, while those maintained on a natural winter light cycle survived a maximum of 4h. Using intracellular sharp electrode recordings from pedal ganglia cluster F neurons we show that there is a photoperiod dependent shift in the response to GABA. Snails exposed to a 16h:8h light:dark cycle in an environmental chamber (induced summer phenotype) exhibited hyperpolarizing inhibitory responses and those exposed to a 8h:16h light:dark cycle (induced winter phenotype) exhibited depolarizing excitatory responses to GABA application. Using gramicidin-perforated patch recordings we also found a photoperiod dependent shift in the reversal potential for GABA. We conclude that the opposing responses of L. stagnalis central neurons to GABA results from a shift in intracellular chloride concentration that is photoperiod dependent and is likely mediated through the relative efficacy of cation chloride co-transporters. Although the physiological ramifications of the photoperiod dependent shift are unknown this work potentially has important implications for the impact of artificial light pollution on animal health. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Genetic Dissection of Photoperiod Response Based on GWAS of Pre-Anthesis Phase Duration in Spring Barley

    PubMed Central

    Alqudah, Ahmad M.; Sharma, Rajiv; Pasam, Raj K.; Graner, Andreas; Kilian, Benjamin; Schnurbusch, Thorsten

    2014-01-01

    Heading time is a complex trait, and natural variation in photoperiod responses is a major factor controlling time to heading, adaptation and grain yield. In barley, previous heading time studies have been mainly conducted under field conditions to measure total days to heading. We followed a novel approach and studied the natural variation of time to heading in a world-wide spring barley collection (218 accessions), comprising of 95 photoperiod-sensitive (Ppd-H1) and 123 accessions with reduced photoperiod sensitivity (ppd-H1) to long-day (LD) through dissecting pre-anthesis development into four major stages and sub-phases. The study was conducted under greenhouse (GH) conditions (LD; 16/8 h; ∼20/∼16°C day/night). Genotyping was performed using a genome-wide high density 9K single nucleotide polymorphisms (SNPs) chip which assayed 7842 SNPs. We used the barley physical map to identify candidate genes underlying genome-wide association scans (GWAS). GWAS for pre-anthesis stages/sub-phases in each photoperiod group provided great power for partitioning genetic effects on floral initiation and heading time. In addition to major genes known to regulate heading time under field conditions, several novel QTL with medium to high effects, including new QTL having major effects on developmental stages/sub-phases were found to be associated in this study. For example, highly associated SNPs tagged the physical regions around HvCO1 (barley CONSTANS1) and BFL (BARLEY FLORICAULA/LEAFY) genes. Based upon our GWAS analysis, we propose a new genetic network model for each photoperiod group, which includes several newly identified genes, such as several HvCO-like genes, belonging to different heading time pathways in barley. PMID:25420105

  15. The nest predator assemblage for songbirds in Mono Lake basin riparian habitats

    Treesearch

    Quresh S. Latif; Sacha K. Heath; Grant Ballard

    2012-01-01

    Because nest predation strongly limits avian fitness, ornithologists identify nest predators to inform ecological research and conservation. During 2002–2008, we used both video-monitoring of natural nests and direct observations of predation to identify nest predators of open-cup nesting riparian songbirds along tributaries of Mono Lake, California. Video cameras at...

  16. Songbird Community Variation Among Five Levels of Overstory Retention in Northern Alabama

    Treesearch

    Adrian A. Lesak; Yong Wang; Callie Jo Schweitzer

    2004-01-01

    We compared songbird communities among varying degrees of overstory tree retention in the oak-hickory forest of the southern Mid-Cumberland Plateau region. Three 20-ha complete block replicates of 5 experimental treatments (15 treatment units, 4 ha per unit) were used. The five treatments were operational shelterwood stands with target overstory retention levels of...

  17. EARLY FLOWERING3 Regulates Flowering in Spring Barley by Mediating Gibberellin Production and FLOWERING LOCUS T Expression[C][W

    PubMed Central

    Boden, Scott A.; Weiss, David; Ross, John J.; Davies, Noel W.; Trevaskis, Ben; Chandler, Peter M.; Swain, Steve M.

    2014-01-01

    EARLY FLOWERING3 (ELF3) is a circadian clock gene that contributes to photoperiod-dependent flowering in plants, with loss-of-function mutants in barley (Hordeum vulgare), legumes, and Arabidopsis thaliana flowering early under noninductive short-day (SD) photoperiods. The barley elf3 mutant displays increased expression of FLOWERING LOCUS T1 (FT1); however, it remains unclear whether this is the only factor responsible for the early flowering phenotype. We show that the early flowering and vegetative growth phenotypes of the barley elf3 mutant are strongly dependent on gibberellin (GA) biosynthesis. Expression of the central GA biosynthesis gene, GA20oxidase2, and production of the bioactive GA, GA1, were significantly increased in elf3 leaves under SDs, relative to the wild type. Inhibition of GA biosynthesis suppressed the early flowering of elf3 under SDs independently of FT1 and was associated with altered expression of floral identity genes at the developing apex. GA is also required for normal flowering of spring barley under inductive photoperiods, with chemical and genetic attenuation of the GA biosynthesis and signaling pathways suppressing inflorescence development under long-day conditions. These findings illustrate that GA is an important floral promoting signal in barley and that ELF3 suppresses flowering under noninductive photoperiods by blocking GA production and FT1 expression. PMID:24781117

  18. Distribution of photoperiod-insensitive allele Ppd-A1a and its effect on heading time in Japanese wheat cultivars.

    PubMed

    Seki, Masako; Chono, Makiko; Nishimura, Tsutomu; Sato, Mikako; Yoshimura, Yasuhiro; Matsunaka, Hitoshi; Fujita, Masaya; Oda, Shunsuke; Kubo, Katashi; Kiribuchi-Otobe, Chikako; Kojima, Hisayo; Nishida, Hidetaka; Kato, Kenji

    2013-09-01

    The Ppd-A1 genotype of 240 Japanese wheat cultivars and 40 foreign cultivars was determined using a PCR-based method. Among Japanese cultivars, only 12 cultivars, all of which were Hokkaido winter wheat, carried the Ppd-A1a allele, while this allele was not found in Hokkaido spring wheat cultivars or Tohoku-Kyushu cultivars. Cultivars with a photoperiod-insensitive allele headed 6.9-9.8 days earlier in Kanto and 2.5 days earlier in Hokkaido than photoperiod-sensitive cultivars. The lower effect of photoperiod-insensitive alleles observed in Hokkaido could be due to the longer day-length at the spike formation stage compared with that in Kanto. Pedigree analysis showed that 'Purple Straw' and 'Tohoku 118' were donors of Ppd-A1a and Ppd-D1a in Hokkaido wheat cultivars, respectively. Wheat cultivars recently developed in Hokkaido carry photoperiod-insensitive alleles at a high frequency. For efficient utilization of Ppd-1 alleles in the Hokkaido wheat-breeding program, the effect of Ppd-1 on growth pattern and grain yield should be investigated. Ppd-A1a may be useful as a unique gene source for fine tuning the heading time in the Tohoku-Kyushu region since the effect of Ppd-A1a on photoperiod insensitivity appears to differ from the effect of Ppd-B1a and Ppd-D1a.

  19. Controls on seasonal patterns of maximum ecosystem carbon uptake and canopy-scale photosynthetic light response: contributions from both temperature and photoperiod.

    PubMed

    Stoy, Paul C; Trowbridge, Amy M; Bauerle, William L

    2014-02-01

    Most models of photosynthetic activity assume that temperature is the dominant control over physiological processes. Recent studies have found, however, that photoperiod is a better descriptor than temperature of the seasonal variability of photosynthetic physiology at the leaf scale. Incorporating photoperiodic control into global models consequently improves their representation of the seasonality and magnitude of atmospheric CO2 concentration. The role of photoperiod versus that of temperature in controlling the seasonal variability of photosynthetic function at the canopy scale remains unexplored. We quantified the seasonal variability of ecosystem-level light response curves using nearly 400 site years of eddy covariance data from over eighty Free Fair-Use sites in the FLUXNET database. Model parameters describing maximum canopy CO2 uptake and the initial slope of the light response curve peaked after peak temperature in about 2/3 of site years examined, emphasizing the important role of temperature in controlling seasonal photosynthetic function. Akaike's Information Criterion analyses indicated that photoperiod should be included in models of seasonal parameter variability in over 90% of the site years investigated here, demonstrating that photoperiod also plays an important role in controlling seasonal photosynthetic function. We also performed a Granger causality analysis on both gross ecosystem productivity (GEP) and GEP normalized by photosynthetic photon flux density (GEP n ). While photoperiod Granger-caused GEP and GEP n in 99 and 92% of all site years, respectively, air temperature Granger-caused GEP in a mere 32% of site years but Granger-caused GEP n in 81% of all site years. Results demonstrate that incorporating photoperiod may be a logical step toward improving models of ecosystem carbon uptake, but not at the expense of including enzyme kinetic-based temperature constraints on canopy-scale photosynthesis.

  20. Effects of Photoperiod on Behavior and Courtship of the Neosho madtom (Noturus placidus)

    USGS Publications Warehouse

    Bulger, Angela G.; Wildhaber, Mark L.; Edds, David R.

    2002-01-01

    To test effects of long and short day-length on behavior of the Neosho madtom (Noturus placidus), we held six pairs of fish in separate tanks under 16 hr (L): 8 hr (D) (long-day) and six pairs under 12 hr (L): 12 hr (D) (short-day) photoperiods. An ethogram was created and behavior was electronically and continuously recorded. Two-minute intervals for each hour over four 4-day periods were examined, and proportion of time active and performing specific behaviors in each tank was analyzed to compare differences between treatments. Individuals held under 16 L, 8 D were more active during the light cycle than those in 12 L, 12 D. Specific behaviors examined included resting, swimming, feeding, aggression, cavity enhancement, and courtship. A higher proportion of time was spent performing cavity enhancement, cavities were deeper, and gravel size in cavities was smaller for those fish in the long-day treatment. Throughout the experiment various courtship behaviors were observed in male-female pairs held in 16 L, 8 D, but no such behaviors were observed in 12L, 12D. The relationships between a long photoperiod and activity, cavity enhancement, and courtship behaviors illustrate the influence of photoperiod on the Neosho madtom reproductive cycle.

  1. Effects of photoperiod on food intake, activity and metabolic rate in adult neutered male cats.

    PubMed

    Kappen, K L; Garner, L M; Kerr, K R; Swanson, K S

    2014-10-01

    With the continued rise in feline obesity, novel weight management strategies are needed. To date, strategies aimed at altering physical activity, an important factor in weight maintenance, have been lacking. Photoperiod is known to cause physiological changes in seasonal mammals, including changes in body weight (BW) and reproductive status. Thus, our objective was to determine the effect of increased photoperiod (longer days) on voluntary physical activity levels, resting metabolic rate (RMR), food intake required to maintain BW, and fasting serum leptin and ghrelin concentrations in adult cats. Eleven healthy, adult, neutered, male domestic shorthair cats were used in a randomized crossover design study. During two 12-week periods, cats were exposed to either a short-day (SD) photoperiod of 8 h light: 16 h dark or a long-day (LD) photoperiod of 16 h light: 8 h dark. Cats were fed a commercial diet to maintain baseline BW. In addition to daily food intake and twice-weekly BW, RMR (via indirect calorimetry), body composition [via dual-energy X-ray absorptiometry (DEXA)] and physical activity (via Actical activity monitors) were measured at week 0 and 12 of each period. Fasting serum leptin and ghrelin concentrations were measured at week 0, 6 and 12 of each period. Average hourly physical activity was greater (p = 0.008) in LD vs. SD cats (3770 vs. 3129 activity counts/h), which was primarily due to increased (p < 0.001) dark period activity (1188 vs. 710 activity counts/h). This corresponded to higher (p < 0.0001) daily metabolizable energy intake (mean over 12-week period: 196 vs. 187 kcal/day), and increased (p = 0.048) RMR in LD cats (9.02 vs. 8.37 kcal/h). Body composition, serum leptin and serum ghrelin were not altered by photoperiod. More research is needed to determine potential mechanisms by which these physiological changes occurred and how they may apply to weight management strategies.

  2. Reproductive allochrony in seasonally sympatric populations maintained by differential response to photoperiod: Implications for population divergence and response to climate change

    USGS Publications Warehouse

    Fudickar, A.M.; Grieves, T.J.; Atwell, Jonathan W.; Stricker, Craig A.; Ketterson, Ellen D.

    2016-01-01

    Reproductive allochrony presents a potential barrier to gene flow and is common in seasonally sympatric migratory and sedentary birds. Mechanisms mediating reproductive allochrony can influence population divergence and the capacity of populations to respond to environmental change. We asked whether reproductive allochrony in seasonally sympatric birds results from a difference in response to supplementary or photoperiodic cues and whether the response varies in relation to the distance separating breeding and wintering locations as measured by stable isotopes. We held seasonally sympatric migratory and sedentary male dark-eyed juncos (Junco hyemalis) in a common garden in early spring under simulated natural changes in photoperiod and made measurements of reproductive and migratory physiology. On the same dates and photoperiods, sedentary juncos had higher testosterone (initial and gonadotropin-releasing hormone induced), more developed cloacal protuberances, and larger testes than migrants. In contrast, migratory juncos had larger fat reserves (fuel for migration). We found a negative relationship between testis mass and feather hydrogen isotope ratios, indicating that testis growth was more delayed in migrants making longer migrations. We conclude that reproductive allochrony in seasonally sympatric migratory and sedentary birds can result from a differential response to photoperiodic cues in a common garden, and as a result, gene flow between migrants and residents may be reduced by photoperiodic control of reproductive development. Further, earlier breeding in response to future climate change may currently be constrained by differential response to photoperiodic cues.

  3. Expression conservation within the circadian clock of a monocot: natural variation at barley Ppd-H1 affects circadian expression of flowering time genes, but not clock orthologs.

    PubMed

    Campoli, Chiara; Shtaya, Munqez; Davis, Seth J; von Korff, Maria

    2012-06-21

    The circadian clock is an endogenous mechanism that coordinates biological processes with daily changes in the environment. In plants, circadian rhythms contribute to both agricultural productivity and evolutionary fitness. In barley, the photoperiod response regulator and flowering-time gene Ppd-H1 is orthologous to the Arabidopsis core-clock gene PRR7. However, relatively little is known about the role of Ppd-H1 and other components of the circadian clock in temperate crop species. In this study, we identified barley clock orthologs and tested the effects of natural genetic variation at Ppd-H1 on diurnal and circadian expression of clock and output genes from the photoperiod-response pathway. Barley clock orthologs HvCCA1, HvGI, HvPRR1, HvPRR37 (Ppd-H1), HvPRR73, HvPRR59 and HvPRR95 showed a high level of sequence similarity and conservation of diurnal and circadian expression patterns, when compared to Arabidopsis. The natural mutation at Ppd-H1 did not affect diurnal or circadian cycling of barley clock genes. However, the Ppd-H1 mutant was found to be arrhythmic under free-running conditions for the photoperiod-response genes HvCO1, HvCO2, and the MADS-box transcription factor and vernalization responsive gene Vrn-H1. We suggest that the described eudicot clock is largely conserved in the monocot barley. However, genetic differentiation within gene families and differences in the function of Ppd-H1 suggest evolutionary modification in the angiosperm clock. Our data indicates that natural variation at Ppd-H1 does not affect the expression level of clock genes, but controls photoperiodic output genes. Circadian control of Vrn-H1 in barley suggests that this vernalization responsive gene is also controlled by the photoperiod-response pathway. Structural and functional characterization of the barley circadian clock will set the basis for future studies of the adaptive significance of the circadian clock in Triticeae species.

  4. Photoperiodic growth control in perennial trees.

    PubMed

    Azeez, Abdul; Sane, Aniruddha P

    2015-01-01

    Plants have to cope with changing seasons and adverse environmental conditions. Being sessile, plants have developed elaborate mechanisms for their survival that allow them to sense and adapt to the environment and reproduce successfully. A major adaptive trait for the survival of trees of temperate and boreal forests is the induction of growth cessation in anticipation of winters. In the last few years enormous progress has been made to elucidate the molecular mechanisms underlying SDs induced growth cessation in model perennial tree hybrid aspen (Populus tremula × P. tremuloides). In this review we discuss the molecular mechanism underlying photoperiodic control of growth cessation and adaptive responses.

  5. Photoperiod control of downstream movements of Atlantic salmon Salmo salar smolts

    USGS Publications Warehouse

    Zydlewski, Gayle B.; Stich, Daniel S.; McCormick, Stephen D.

    2014-01-01

    This study provides the first direct observations that photoperiod controls the initiation of downstream movement in Atlantic salmon Salmo salar smolts. Under simulated natural day length (LDN) conditions and seasonal increases in temperature, smolts increased their downstream movements five-fold for a period of 1 month in late spring. Under the same conditions, parr did not show changes in downstream movement behaviour. When given a shortened day length (10L:14D) beginning in late winter, smolts did not increase the number of downstream movements. An early increase in day length (16L:8D) in late winter resulted in earlier initiation and termination of downstream movements compared to the LDN group. Physiological status and behaviour were related but not completely coincident: gill Na+/K+-ATPase activity increased in all treatments and thyroid hormone was elevated prior to movement in 16L:8D treatment. The most parsimonious model describing downstream movement of smolts included synergistic effects of photoperiod treatment and temperature, indicating that peak movements occurred at colder temperatures in the 16L:8D treatment than in LDN, and temperature did not influence movement of smolts in the 10L:14D treatment. The complicated interactions of photoperiod and temperature are not surprising since many organisms have evolved to rely on correlations among environmental cues and windows of opportunity to time behaviours associated with life-history transitions. These complicated interactions, however, have serious implications for phenological adjustments and persistence ofS. salar populations in response to climate change.

  6. Effects of Temperature, Photoperiod, and Rainfall on Morphometric Variation of Diaphorina citri (Hemiptera: Liviidae).

    PubMed

    Paris, Thomson M; Allan, Sandra A; Hall, David G; Hentz, Matthew G; Croxton, Scott D; Ainpudi, Niharika; Stansly, Philip A

    2017-02-01

    Phenotypic plasticity provides a mechanism by which an organism can adapt to new or changing environments. Earlier studies have demonstrated the variability of Diaphorina citri Kuwayama (Asian citrus psyllid) population dynamics, but no analysis of morphological changes induced by seasonal or artificial laboratory-induced conditions has yet been documented. Such morphometric variation has been found to correspond in dispersal capabilities in several insect taxa. In this study, the effects of temperature and photoperiod on morphometric variation of D. citri were examined through laboratory rearing of psyllids under controlled temperatures (20 °C, 28 °C, and 30 °C) and under a short photoperiod of 10.5:13.5 (L:D) h and a long photoperiod of 16:8 (L:D) h. Diaphorina citri were field-collected monthly from three citrus groves in Fort Pierce, Gainesville, and Immokalee, FL, to evaluate potential field-associated environmental effects. Both traditional and geometric morphometric data were used to analyze the correlation between environmental and morphometric variation. A strong correlation was found between temperature and shape change, with larger and broader wings at colder temperatures in the laboratory. Short day length resulted in shorter and narrower wings as well. From the field, temperature, rainfall, and photoperiod were moderately associated with shape parameters. Adult D. citri with blue/green abdomens collected in the laboratory and field studies were larger in size and shape than those with brown/gray abdomens. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.

  7. Peripheral auditory processing changes seasonally in Gambel’s white-crowned sparrow

    PubMed Central

    Caras, Melissa L.; Brenowitz, Eliot; Rubel, Edwin W

    2010-01-01

    Song in oscine birds is a learned behavior that plays important roles in breeding. Pronounced seasonal differences in song behavior, and in the morphology and physiology of the neural circuit underlying song production are well documented in many songbird species. Androgenic and estrogenic hormones largely mediate these seasonal changes. While much work has focused on the hormonal mechanisms underlying seasonal plasticity in songbird vocal production, relatively less work has investigated seasonal and hormonal effects on songbird auditory processing, particularly at a peripheral level. We addressed this issue in Gambel’s white-crowned sparrow (Zonotrichia leucophrys gambelii), a highly seasonal breeder. Photoperiod and hormone levels were manipulated in the laboratory to simulate natural breeding and non-breeding conditions. Peripheral auditory function was assessed by measuring the auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs) of males and females in both conditions. Birds exposed to breeding-like conditions demonstrated elevated thresholds and prolonged peak latencies compared with birds housed under non-breeding-like conditions. There were no changes in DPOAEs, however, which indicates that the seasonal differences in ABRs do not arise from changes in hair cell function. These results suggest that seasons and hormones impact auditory processing as well as vocal production in wild songbirds. PMID:20563817

  8. Melatonin and 6-methoxy-2-benzoxazolinone (6-MBOA) alter the response of the male Syrian hamster to natural photoperiod

    NASA Astrophysics Data System (ADS)

    Vaughan, M. K.; Little, J. C.; Powell, D. C.; Puig-Domingo, M.; Reiter, R. J.

    1988-06-01

    Adult male hamsters bearing either a blank beeswax, 6-methoxy-2-benzoxazolinone (6-MBOA), or melatonin pellet were exposed to 8 weeks (Oct. 6 Dec. 6) of natural autumn decreasing photoperiod (<11 h light) and temperature conditions (mean 10°C for last 4 weeks) or to a 14 h light/10 h dark (14L∶10D) photoperiod and controlled temperature (20°C). Melatonin but not 6-MBOA pellets partially prevented the combined effects of short photoperiod and cold temperatures on the testes and accessory organs. However, both 6-MBOA-and melatonin-treated hamsters maintained outdoors had significantly higher pituitary follicle stimulating hormone (FSH) values compared to their respective indoor-treated controls or to the animals kept outdoors and treated with a blank beeswax pellet. When one compares the various effects of 6-MBOA and melatonin (2 mg/month) on the reproductive system of the male hamster, 6-MBOA is not as effective as melatonin in altering reproductive responses to short photoperiod and cool temperatures at the dose administered.

  9. Effects of photoperiod, growth temperature and cold acclimatisation on glucosinolates, sugars and fatty acids in kale.

    PubMed

    Steindal, Anne Linn Hykkerud; Rødven, Rolf; Hansen, Espen; Mølmann, Jørgen

    2015-05-01

    Curly kale is a robust, cold tolerant plant with a high content of health-promoting compounds, grown at a range of latitudes. To assess the effects of temperature, photoperiod and cold acclimatisation on levels of glucosinolates, fatty acids and soluble sugars in kale, an experiment was set up under controlled conditions. Treatments consisted of combinations of the temperatures 15/9 or 21/15 °C, and photoperiods of 12 or 24h, followed by a cold acclimatisation period. Levels of glucosinolates and fatty acid types in leaves were affected by growth conditions and cold acclimatisation, being generally highest before acclimatisation. The effects of growth temperature and photoperiod on freezing tolerance were most pronounced in plants grown without cold acclimatisation. The results indicate that cold acclimatisation can increase the content of soluble sugar and can thereby improve the taste, whilst the content of unsaturated fatty and glucosinolates acids may decrease. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Feather growth influences blood mercury level of young songbirds.

    PubMed

    Condon, Anne M; Cristol, Daniel A

    2009-02-01

    Dynamics of mercury in feathers and blood of free-living songbirds is poorly understood. Nestling eastern bluebirds (Sialia sialis) living along the mercury-contaminated South River (Virginia, USA) had blood mercury levels an order of magnitude lower than their parents (nestling: 0.09 +/- 0.06 mg/kg [mean +/- standard deviation], n = 156; adult: 1.21 +/- 0.57 mg/kg, n = 86). To test whether this low blood mercury was the result of mercury sequestration in rapidly growing feathers, we repeatedly sampled free-living juveniles throughout the period of feather growth and molt. Mean blood mercury concentrations increased to 0.52 +/- 0.36 mg/kg (n = 44) after the completion of feather growth. Some individuals had reached adult blood mercury levels within three months of leaving the nest, but levels dropped to 0.20 +/- 0.09 mg/kg (n = 11) once the autumn molt had begun. Most studies of mercury contamination in juvenile birds have focused on recently hatched young with thousands of rapidly growing feathers. However, the highest risk period for mercury intoxication in young birds may be during the vulnerable period after fledging, when feathers no longer serve as a buffer against dietary mercury. We found that nestling blood mercury levels were not indicative of the extent of contamination because a large portion of the ingested mercury ended up in feathers. The present study demonstrates unequivocally that in songbirds blood mercury level is influenced strongly by the growth and molt of feathers.

  11. How the songbird brain listens to its own songs

    NASA Astrophysics Data System (ADS)

    Hahnloser, Richard

    2010-03-01

    Songbirds are capable of vocal learning and communication and are ideally suited to the study of neural mechanisms of auditory feedback processing. When a songbird is deafened in the early sensorimotor phase after tutoring, it fails to imitate the song of its tutor and develops a highly aberrant song. It is also known that birds are capable of storing a long-term memory of tutor song and that they need intact auditory feedback to match their own vocalizations to the tutor's song. Based on these behavioral observations, we investigate feedback processing in single auditory forebrain neurons of juvenile zebra finches that are in a late developmental stage of song learning. We implant birds with miniature motorized microdrives that allow us to record the electrical activity of single neurons while birds are freely moving and singing in their cages. Occasionally, we deliver a brief sound through a loudspeaker to perturb the auditory feedback the bird experiences during singing. These acoustic perturbations of auditory feedback reveal complex sensitivity that cannot be predicted from passive playback responses. Some neurons are highly feedback sensitive in that they respond vigorously to song perturbations, but not to unperturbed songs or perturbed playback. These findings suggest that a computational function of forebrain auditory areas may be to detect errors between actual feedback and mirrored feedback deriving from an internal model of the bird's own song or that of its tutor.

  12. Agricultural management affects evolutionary processes in a migratory songbird

    USGS Publications Warehouse

    Perlut, N.G.; Freeman-Gallant, C. R.; Strong, A.M.; Donovan, T.M.; Kilpatrick, C.W.; Zalik, N.J.

    2008-01-01

    Hay harvests have detrimental ecological effects on breeding songbirds, as harvesting results in nest failure. Importantly, whether harvesting also affects evolutionary processes is not known. We explored how hay harvest affected social and genetic mating patterns, and thus, the overall opportunity for sexual selection and evolutionary processes for a ground-nesting songbird, the Savannah sparrow (Passerculus sandwichensis). On an unharvested field, 55% of females were in polygynous associations, and social polygyny was associated with greater rates of extra-pair paternity (EPP). In this treatment, synchrony explained variation in EPP rates, as broods by more synchronous females had more EPP than broods by asynchronous females. In contrast, on a harvested field, simultaneous nest failure caused by haying dramatically decreased the overall incidence of EPP by increasing the occurrence of social monogamy and, apparently, the ability of polygynous males to maintain paternity in their own nests. Despite increased social and genetic monogamy, these haying-mediated changes in mating systems resulted in greater than twofold increase in the opportunity for sexual selection. This effect arose, in part, from a 30% increase in the variance associated with within-pair fertilization success, relative to the unharvested field. This effect was caused by a notable increase (+110%) in variance associated with the quality of social mates following simultaneous nest failure. Because up to 40% of regional habitat is harvested by early June, these data may demonstrate a strong population-level effect on mating systems, sexual selection, and consequently, evolutionary processes. ?? 2008 The Authors.

  13. Development of neural responsivity to vocal sounds in higher level auditory cortex of songbirds

    PubMed Central

    Miller-Sims, Vanessa C.

    2014-01-01

    Like humans, songbirds learn vocal sounds from “tutors” during a sensitive period of development. Vocal learning in songbirds therefore provides a powerful model system for investigating neural mechanisms by which memories of learned vocal sounds are stored. This study examined whether NCM (caudo-medial nidopallium), a region of higher level auditory cortex in songbirds, serves as a locus where a neural memory of tutor sounds is acquired during early stages of vocal learning. NCM neurons respond well to complex auditory stimuli, and evoked activity in many NCM neurons habituates such that the response to a stimulus that is heard repeatedly decreases to approximately one-half its original level (stimulus-specific adaptation). The rate of neural habituation serves as an index of familiarity, being low for familiar sounds, but high for novel sounds. We found that response strength across different song stimuli was higher in NCM neurons of adult zebra finches than in juveniles, and that only adult NCM responded selectively to tutor song. The rate of habituation across both tutor song and novel conspecific songs was lower in adult than in juvenile NCM, indicating higher familiarity and a more persistent response to song stimuli in adults. In juvenile birds that have memorized tutor vocal sounds, neural habituation was higher for tutor song than for a familiar conspecific song. This unexpected result suggests that the response to tutor song in NCM at this age may be subject to top-down influences that maintain the tutor song as a salient stimulus, despite its high level of familiarity. PMID:24694936

  14. Tap dancing birds: the multimodal mutual courtship display of males and females in a socially monogamous songbird.

    PubMed

    Ota, Nao; Gahr, Manfred; Soma, Masayo

    2015-11-19

    According to classical sexual selection theory, complex multimodal courtship displays have evolved in males through female choice. While it is well-known that socially monogamous songbird males sing to attract females, we report here the first example of a multimodal dance display that is not a uniquely male trait in these birds. In the blue-capped cordon-bleu (Uraeginthus cyanocephalus), a socially monogamous songbird, both sexes perform courtship displays that are characterised by singing and simultaneous visual displays. By recording these displays with a high-speed video camera, we discovered that in addition to bobbing, their visual courtship display includes quite rapid step-dancing, which is assumed to produce vibrations and/or presumably non-vocal sounds. Dance performances did not differ between sexes but varied among individuals. Both male and female cordon-bleus intensified their dance performances when their mate was on the same perch. The multimodal (acoustic, visual, tactile) and multicomponent (vocal and non-vocal sounds) courtship display observed was a combination of several motor behaviours (singing, bobbing, stepping). The fact that both sexes of this socially monogamous songbird perform such a complex courtship display is a novel finding and suggests that the evolution of multimodal courtship display as an intersexual communication should be considered.

  15. Distribution of photoperiod-insensitive allele Ppd-A1a and its effect on heading time in Japanese wheat cultivars

    PubMed Central

    Seki, Masako; Chono, Makiko; Nishimura, Tsutomu; Sato, Mikako; Yoshimura, Yasuhiro; Matsunaka, Hitoshi; Fujita, Masaya; Oda, Shunsuke; Kubo, Katashi; Kiribuchi-Otobe, Chikako; Kojima, Hisayo; Nishida, Hidetaka; Kato, Kenji

    2013-01-01

    The Ppd-A1 genotype of 240 Japanese wheat cultivars and 40 foreign cultivars was determined using a PCR-based method. Among Japanese cultivars, only 12 cultivars, all of which were Hokkaido winter wheat, carried the Ppd-A1a allele, while this allele was not found in Hokkaido spring wheat cultivars or Tohoku-Kyushu cultivars. Cultivars with a photoperiod-insensitive allele headed 6.9–9.8 days earlier in Kanto and 2.5 days earlier in Hokkaido than photoperiod-sensitive cultivars. The lower effect of photoperiod-insensitive alleles observed in Hokkaido could be due to the longer day-length at the spike formation stage compared with that in Kanto. Pedigree analysis showed that ‘Purple Straw’ and ‘Tohoku 118’ were donors of Ppd-A1a and Ppd-D1a in Hokkaido wheat cultivars, respectively. Wheat cultivars recently developed in Hokkaido carry photoperiod-insensitive alleles at a high frequency. For efficient utilization of Ppd-1 alleles in the Hokkaido wheat-breeding program, the effect of Ppd-1 on growth pattern and grain yield should be investigated. Ppd-A1a may be useful as a unique gene source for fine tuning the heading time in the Tohoku-Kyushu region since the effect of Ppd-A1a on photoperiod insensitivity appears to differ from the effect of Ppd-B1a and Ppd-D1a. PMID:24273426

  16. Photoperiod affects the expression of sex and species differences in leukocyte number and leukocyte trafficking in congeneric hamsters.

    PubMed

    Bilbo, S D; Dhabhar, F S; Viswanathan, K; Saul, A; Nelson, R J

    2003-11-01

    Sex differences in immune function are well documented. These sex differences may be modulated by social and environmental factors. Individuals of polygynous species generally exhibit more pronounced sex differences in immune parameters than individuals of monogamous species, often displaying an energetic trade-off between enhanced immunity and high mating success. During winter, animals contend with environmental conditions (e.g. low temperatures and decreased food availability) that evoke energetic-stress responses; many mammals restrict reproduction in response to photoperiod as part of an annual winter coping strategy. To test the hypothesis that extant sex and species differences in immune surveillance may be modulated by photoperiod, we examined leukocyte numbers in males and females of two closely related hamster species (Phodopus). As predicted, uniparental P. sungorus exhibited a robust sex difference, with total white blood cells, total lymphocytes, T cells, and B cells higher in females than males, during long days when reproduction occurs, but not during short days when reproduction usually stops. In contrast, biparental male and female P. campbelli exhibited comparable leukocyte numbers during both long and short days. To study sex differences in stress responses, we also examined immune cell trafficking in response to an acute (2 h) restraint stressor. During stressful challenges, it appears beneficial for immune cells to exit the blood and move to primary immune defense areas such as the skin, in preparation for potential injury or infection. Acute stress moved lymphocytes and monocytes out of the blood in all animals. Blood cortisol concentrations were increased in P. sungorus females compared to males at baseline (52%) and in response to restraint stress (38%), but only in long days. P. campbelli males and females exhibited comparable blood cortisol and stress responses during both long and short days. Our results suggest that interactions among

  17. Seasonal and photoperiodic effects on lipid droplet size and lipid peroxidation in the brown adipose tissue of bank voles (Myodes glareolus).

    PubMed

    Bonda-Ostaszewska, Elżbieta; Włostowski, Tadeusz; Krasowska, Alicja; Kozłowski, Paweł

    2012-10-01

    Seasonal changes in lipid droplet size and lipid peroxidation in the brown adipose tissue (BAT) of wild bank voles were examined. In addition, a role of photoperiod in these changes was studied; bank voles were held from the birth under long photoperiod (LP) for 12 weeks, and then half of them was transferred to short photoperiod (SP) for 6 weeks and another one remained under LP. In the wild bank voles the absolute BAT weight was seasonally constant, while the significant differences in the lipid droplet size were observed. The smallest lipid droplets (mean, 11 μm(2)) were seen in winter; they increased by 30 % in spring and reached the highest size (24 μm(2)) in summer. Lipid peroxidation in the BAT did not differ significantly between the seasons, although high intraseason variation of this process was noted. The laboratory experiment revealed that the size of lipid droplets was determined by photoperiod; SP induced 13-fold decrease, and continuous exposure to LP brought about a further 2.5-fold increase in the size of lipid droplets. Conversely, a significant decrease in lipid peroxidation was seen in LP bank voles in comparison with the SP animals. The data indicate that short photoperiod is responsible for the small size of lipid droplets in the BAT of bank voles during winter, which may be a necessary requirement for high thermogenic capacity of the tissue. Photoperiod appears also to affect lipid peroxidation in the BAT of these animals.

  18. Metabolic influences on circadian rhythmicity in Siberian and Syrian hamsters exposed to long photoperiods.

    PubMed

    Challet, E; Kolker, D E; Turek, F W

    2000-01-01

    Calorie restriction and other situations of reduced glucose availability in rodents alter the entraining effects of light on the circadian pacemaker located in the suprachiasmatic nuclei. Siberian and Syrian hamsters are photoperiodic species that are sexually active when exposed to long summer-like photoperiods, while both species show opposite changes in body mass when transferred from long to short or short to long days. Because metabolic cues may fine tune the photoperiodic responses via the suprachiasmatic nuclei, we tested whether timed calorie restriction can alter the photic synchronization of the light-entrainable pacemaker in these two hamster species exposed to long photoperiods. Siberian and Syrian hamsters were exposed to 16 h:8 h light:dark cycles and received daily hypocaloric (75% of daily food intake) or normocaloric diet (100% of daily food intake) 4 h after light onset. Four weeks later, hamsters were transferred to constant darkness and fed ad libitum. The onset of the nocturnal pattern of locomotor activity was phase advanced by 1.5 h in calorie-restricted Siberian hamsters, but not in Syrian hamsters. The lack of phase change in calorie-restricted Syrian hamsters was also observed in individuals exposed to 14 h:10 h dim light:dark cycles and fed with lower hypocaloric food (i.e. 60% of daily food intake) 2 h after light onset. Moreover, in hamsters housed in constant darkness and fed ad lib., light-induced phase shifts of the locomotor activity in Siberian hamsters, but not in Syrian hamsters were significantly reduced when glucose utilization was blocked by pretreatment with 500 mg/kg i.p. 2-deoxy-D-glucose. Taken together, these results show that the photic synchronization of the light-entrainable pacemaker can be modulated by metabolic cues in Siberian hamsters, but not in Syrian hamsters maintained on long days.

  19. The respiratory-vocal system of songbirds: anatomy, physiology, and neural control.

    PubMed

    Schmidt, Marc F; Martin Wild, J

    2014-01-01

    This wide-ranging review presents an overview of the respiratory-vocal system in songbirds, which are the only other vertebrate group known to display a degree of respiratory control during song rivalling that of humans during speech; this despite the fact that the peripheral components of both the respiratory and vocal systems differ substantially in the two groups. We first provide a brief description of these peripheral components in songbirds (lungs, air sacs and respiratory muscles, vocal organ (syrinx), upper vocal tract) and then proceed to a review of the organization of central respiratory-related neurons in the spinal cord and brainstem, the latter having an organization fundamentally similar to that of the ventral respiratory group of mammals. The second half of the review describes the nature of the motor commands generated in a specialized "cortical" song control circuit and how these might engage brainstem respiratory networks to shape the temporal structure of song. We also discuss a bilaterally projecting "respiratory-thalamic" pathway that links the respiratory system to "cortical" song control nuclei. This necessary pathway for song originates in the brainstem's primary inspiratory center and is hypothesized to play a vital role in synchronizing song motor commands both within and across hemispheres. © 2014 Elsevier B.V. All rights reserved.

  20. The respiratory-vocal system of songbirds: Anatomy, physiology, and neural control

    PubMed Central

    Schmidt, Marc F.; Wild, J. Martin

    2015-01-01

    This wide-ranging review presents an overview of the respiratory-vocal system in songbirds, which are the only other vertebrate group known to display a degree of respiratory control during song rivalling that of humans during speech; this despite the fact that the peripheral components of both the respiratory and vocal systems differ substantially in the two groups. We first provide a brief description of these peripheral components in songbirds (lungs, air sacs and respiratory muscles, vocal organ (syrinx), upper vocal tract) and then proceed to a review of the organization of central respiratory-related neurons in the spinal cord and brainstem, the latter having an organization fundamentally similar to that of the ventral respiratory group of mammals. The second half of the review describes the nature of the motor commands generated in a specialized “cortical” song control circuit and how these might engage brainstem respiratory networks to shape the temporal structure of song. We also discuss a bilaterally projecting “respiratory-thalamic” pathway that links the respiratory system to “cortical” song control nuclei. This necessary pathway for song originates in the brainstem’s primary inspiratory center and is hypothesized to play a vital role in synchronizing song motor commands both within and across hemispheres. PMID:25194204

  1. Mechanisms and time course of vocal learning and consolidation in the adult songbird.

    PubMed

    Warren, Timothy L; Tumer, Evren C; Charlesworth, Jonathan D; Brainard, Michael S

    2011-10-01

    In songbirds, the basal ganglia outflow nucleus LMAN is a cortical analog that is required for several forms of song plasticity and learning. Moreover, in adults, inactivating LMAN can reverse the initial expression of learning driven via aversive reinforcement. In the present study, we investigated how LMAN contributes to both reinforcement-driven learning and a self-driven recovery process in adult Bengalese finches. We first drove changes in the fundamental frequency of targeted song syllables and compared the effects of inactivating LMAN with the effects of interfering with N-methyl-d-aspartate (NMDA) receptor-dependent transmission from LMAN to one of its principal targets, the song premotor nucleus RA. Inactivating LMAN and blocking NMDA receptors in RA caused indistinguishable reversions in the expression of learning, indicating that LMAN contributes to learning through NMDA receptor-mediated glutamatergic transmission to RA. We next assessed how LMAN's role evolves over time by maintaining learned changes to song while periodically inactivating LMAN. The expression of learning consolidated to become LMAN independent over multiple days, indicating that this form of consolidation is not completed over one night, as previously suggested, and instead may occur gradually during singing. Subsequent cessation of reinforcement was followed by a gradual self-driven recovery of original song structure, indicating that consolidation does not correspond with the lasting retention of changes to song. Finally, for self-driven recovery, as for reinforcement-driven learning, LMAN was required for the expression of initial, but not later, changes to song. Our results indicate that NMDA receptor-dependent transmission from LMAN to RA plays an essential role in the initial expression of two distinct forms of vocal learning and that this role gradually wanes over a multiday process of consolidation. The results support an emerging view that cortical-basal ganglia circuits can

  2. Reproductive responses of male Brandt's voles ( Lasiopodomys brandtii) to 6-methoxybenzoxazolinone (6-MBOA) under short photoperiod

    NASA Astrophysics Data System (ADS)

    Dai, Xin; Jiang, Lian Yu; Han, Mei; Ye, Man Hong; Wang, Ai Qin; Wei, Wan Hong; Yang, Sheng Mei

    2016-04-01

    The plant secondary metabolite 6-methoxybenzoxazolinone (6-MBOA) can stimulate and enhance animal reproduction. This compound has been successfully detected in Leymus chinensis, which is the main diet of Brandt's voles. The aim of this study was to investigate the effect of different 6-MBOA doses on the reproductive physiology of male Brandt's voles under a short photoperiod. The results showed that 6-MBOA administration increased relative testis weight, regardless of the dose, but it had little effect on the body mass. Low and middle doses of 6-MBOA increased the concentrations of luteinizing hormone and testosterone in the serum and the mRNA levels of StAR and CYP11a1 in the testes. However, 6-MBOA did not cause any significant increase in the mRNA levels of KiSS-1, GPR54, and GnRH compared to those in the control group. The mRNA level of KiSS-1 in the arcuate nucleus (ARC) was higher than that in the anteroventral periventricular nucleus (AVPV). Collectively, our results demonstrated that the number of KiSS-1-expressing neurons located in the ARC was the highest, and that 6-MBOA, which might modulate the reproductive activity along the hypothalamic-pituitary-gonadal axis, had a dose-dependent stimulatory effect on the reproductive activity of Brandt's voles under a short photoperiod. Our study provided insights into the mechanism of 6-MBOA action and the factors influencing the onset of reproduction in Brandt's voles.

  3. Reproductive responses of male Brandt's voles (Lasiopodomys brandtii) to 6-methoxybenzoxazolinone (6-MBOA) under short photoperiod.

    PubMed

    Dai, Xin; Jiang, Lian Yu; Han, Mei; Ye, Man Hong; Wang, Ai Qin; Wei, Wan Hong; Yang, Sheng Mei

    2016-04-01

    The plant secondary metabolite 6-methoxybenzoxazolinone (6-MBOA) can stimulate and enhance animal reproduction. This compound has been successfully detected in Leymus chinensis, which is the main diet of Brandt's voles. The aim of this study was to investigate the effect of different 6-MBOA doses on the reproductive physiology of male Brandt's voles under a short photoperiod. The results showed that 6-MBOA administration increased relative testis weight, regardless of the dose, but it had little effect on the body mass. Low and middle doses of 6-MBOA increased the concentrations of luteinizing hormone and testosterone in the serum and the mRNA levels of StAR and CYP11a1 in the testes. However, 6-MBOA did not cause any significant increase in the mRNA levels of KiSS-1, GPR54, and GnRH compared to those in the control group. The mRNA level of KiSS-1 in the arcuate nucleus (ARC) was higher than that in the anteroventral periventricular nucleus (AVPV). Collectively, our results demonstrated that the number of KiSS-1-expressing neurons located in the ARC was the highest, and that 6-MBOA, which might modulate the reproductive activity along the hypothalamic-pituitary-gonadal axis, had a dose-dependent stimulatory effect on the reproductive activity of Brandt's voles under a short photoperiod. Our study provided insights into the mechanism of 6-MBOA action and the factors influencing the onset of reproduction in Brandt's voles.

  4. Non-target effects on songbirds from habitat manipulation for Greater Sage-Grouse: Implications for the umbrella species concept

    USGS Publications Warehouse

    Carlisle, Jason D.; Chalfoun, Anna D.; Smith, Kurt T.; Beck, Jeffery L.

    2018-01-01

    The “umbrella species” concept is a conservation strategy in which creating and managing reserve areas to meet the needs of one species is thought to benefit other species indirectly. Broad-scale habitat protections on behalf of an umbrella species are assumed to benefit co-occurring taxa, but targeted management actions to improve local habitat suitability for the umbrella species may produce unintended effects on other species. Our objective was to quantify the effects of a common habitat treatment (mowing of big sagebrush [Artemisia tridentata]) intended to benefit a high-profile umbrella species (Greater Sage-Grouse [Centrocercus urophasianus]) on 3 sympatric songbird species of concern. We used a before–after control-impact experimental design spanning 3 yr in Wyoming, USA, to quantify the effect of mowing on the abundance, nest-site selection, nestling condition, and nest survival of 2 sagebrush-obligate songbirds (Brewer's Sparrow [Spizella breweri] and Sage Thrasher [Oreoscoptes montanus]) and one open-habitat generalist songbird (Vesper Sparrow [Pooecetes gramineus]). Mowing was associated with lower abundance of Brewer's Sparrows and Sage Thrashers but higher abundance of Vesper Sparrows. We found no Brewer's Sparrows or Sage Thrashers nesting in the mowed footprint posttreatment, which suggests complete loss of nesting habitat for these species. Mowing was associated with higher nestling condition and nest survival for Vesper Sparrows but not for the sagebrush-obligate species. Management prescriptions that remove woody biomass within a mosaic of intact habitat may be tolerated by sagebrush-obligate songbirds but are likely more beneficial for open-habitat generalist species. By definition, umbrella species conservation entails habitat protections at broad spatial scales. We caution that habitat manipulations to benefit Greater Sage-Grouse could negatively affect nontarget species of conservation concern if implemented across large spatial extents.

  5. Lateralized activation of Cluster N in the brains of migratory songbirds

    PubMed Central

    Liedvogel, Miriam; Feenders, Gesa; Wada, Kazuhiro; Troje, Nikolaus F.; Jarvis, Erich D.; Mouritsen, Henrik

    2008-01-01

    Cluster N is a cluster of forebrain regions found in night-migratory songbirds that shows high activation of activity-dependent gene expression during night-time vision. We have suggested that Cluster N may function as a specialized night-vision area in night-migratory birds and that it may be involved in processing light-mediated magnetic compass information. Here, we investigated these ideas. We found a significant lateralized dominance of Cluster N activation in the right hemisphere of European robins (Erithacus rubecula). Activation predominantly originated from the contralateral (left) eye. Garden warblers (Sylvia borin) tested under different magnetic field conditions and under monochromatic red light did not show significant differences in Cluster N activation. In the fairly sedentary Sardinian warbler (Sylvia melanocephala), which belongs to the same phyolgenetic clade, Cluster N showed prominent activation levels, similar to that observed in garden warblers and European robins. Thus, it seems that Cluster N activation occurs at night in all species within predominantly migratory groups of birds, probably because such birds have the capability of switching between migratory and sedentary life styles. The activation studies suggest that although Cluster N is lateralized, as is the dependence on magnetic compass orientation, either Cluster N is not involved in magnetic processing or the magnetic modulations of the primary visual signal, forming the basis for the currently supported light-dependent magnetic compass mechanism, are relatively small such that activity-dependent gene expression changes are not sensitive enough to pick them up. PMID:17331212

  6. Reducing impacts of brood parasitism by Brown-headed Cowbirds on riparian-nesting migratory songbirds

    Treesearch

    Sara H. Schweitzer; Deborah M. Finch; David M. Leslie

    1996-01-01

    Riparian habitats throughout the Southwest have been altered directly and indirectly by human activities. Many migrant songbird species specific to riparian communities during the breeding season are experiencing population declines. Conversely, the Brown-headed Cowbird (Molothrus ater) benefits from fragmentation of, and livestock grazing in and near riparian habitat...

  7. Sensory Coding and Sensitivity to Local Estrogens Shift during Critical Period Milestones in the Auditory Cortex of Male Songbirds

    PubMed Central

    2017-01-01

    Abstract Vocal learning occurs during an experience-dependent, age-limited critical period early in development. In songbirds, vocal learning begins when presinging birds acquire an auditory memory of their tutor’s song (sensory phase) followed by the onset of vocal production and refinement (sensorimotor phase). Hearing is necessary throughout the vocal learning critical period. One key brain area for songbird auditory processing is the caudomedial nidopallium (NCM), a telencephalic region analogous to mammalian auditory cortex. Despite NCM’s established role in auditory processing, it is unclear how the response properties of NCM neurons may shift across development. Moreover, communication processing in NCM is rapidly enhanced by local 17β-estradiol (E2) administration in adult songbirds; however, the function of dynamically fluctuating E2 in NCM during development is unknown. We collected bilateral extracellular recordings in NCM coupled with reverse microdialysis delivery in juvenile male zebra finches (Taeniopygia guttata) across the vocal learning critical period. We found that auditory-evoked activity and coding accuracy were substantially higher in the NCM of sensory-aged animals compared to sensorimotor-aged animals. Further, we observed both age-dependent and lateralized effects of local E2 administration on sensory processing. In sensory-aged subjects, E2 decreased auditory responsiveness across both hemispheres; however, a similar trend was observed in age-matched control subjects. In sensorimotor-aged subjects, E2 dampened auditory responsiveness in left NCM but enhanced auditory responsiveness in right NCM. Our results reveal an age-dependent physiological shift in auditory processing and lateralized E2 sensitivity that each precisely track a key neural “switch point” from purely sensory (pre-singing) to sensorimotor (singing) in developing songbirds. PMID:29255797

  8. Sensory Coding and Sensitivity to Local Estrogens Shift during Critical Period Milestones in the Auditory Cortex of Male Songbirds.

    PubMed

    Vahaba, Daniel M; Macedo-Lima, Matheus; Remage-Healey, Luke

    2017-01-01

    Vocal learning occurs during an experience-dependent, age-limited critical period early in development. In songbirds, vocal learning begins when presinging birds acquire an auditory memory of their tutor's song (sensory phase) followed by the onset of vocal production and refinement (sensorimotor phase). Hearing is necessary throughout the vocal learning critical period. One key brain area for songbird auditory processing is the caudomedial nidopallium (NCM), a telencephalic region analogous to mammalian auditory cortex. Despite NCM's established role in auditory processing, it is unclear how the response properties of NCM neurons may shift across development. Moreover, communication processing in NCM is rapidly enhanced by local 17β-estradiol (E2) administration in adult songbirds; however, the function of dynamically fluctuating E 2 in NCM during development is unknown. We collected bilateral extracellular recordings in NCM coupled with reverse microdialysis delivery in juvenile male zebra finches ( Taeniopygia guttata ) across the vocal learning critical period. We found that auditory-evoked activity and coding accuracy were substantially higher in the NCM of sensory-aged animals compared to sensorimotor-aged animals. Further, we observed both age-dependent and lateralized effects of local E 2 administration on sensory processing. In sensory-aged subjects, E 2 decreased auditory responsiveness across both hemispheres; however, a similar trend was observed in age-matched control subjects. In sensorimotor-aged subjects, E 2 dampened auditory responsiveness in left NCM but enhanced auditory responsiveness in right NCM. Our results reveal an age-dependent physiological shift in auditory processing and lateralized E 2 sensitivity that each precisely track a key neural "switch point" from purely sensory (pre-singing) to sensorimotor (singing) in developing songbirds.

  9. Photoperiod- and temperature-mediated control of growth cessation and dormancy in trees: a molecular perspective.

    PubMed

    Maurya, Jay P; Bhalerao, Rishikesh P

    2017-09-01

    How plants adapt their developmental patterns to regular seasonal changes is an important question in biology. The annual growth cycle in perennial long-lived trees is yet another example of how plants can adapt to seasonal changes. The two main signals that plants rely on to respond to seasonal changes are photoperiod and temperature, and these signals have critical roles in the temporal regulation of the annual growth cycle of trees. This review presents the latest findings to provide insight into the molecular mechanisms that underlie how photoperiodic and temperature signals regulate seasonal growth in trees. The results point to a high level of conservation in the signalling pathways that mediate photoperiodic control of seasonal growth in trees and flowering in annual plants such as arabidopsis. Furthermore, the data indicate that symplastic communication may mediate certain aspects of seasonal growth. Although considerable insight into the control of phenology in model plants such as poplar and spruce has been obtained, the future challenge is extending these studies to other, non-model trees. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  10. Are Forest Songbirds Declining? Status Assessment from the Southern Appalachians and Northeastern Forests

    Treesearch

    Kathleen E. Franzreb; Kenneth V. Rosenberg

    1997-01-01

    Reported declines in populations of migratory songbirds in the eastern United States (Robbins et al. 1989, Askins et al. 1990, Hagan and Johnston 1992) have created a great deal of concern among researchers, land managers and conservationists, resulting in the formation of the large bird-conservation consortium, Partners In Flight. Among the causes implicated in these...

  11. Predation of Songbird Nests Differs By Predator and Between Field and Forest Habitats

    Treesearch

    Frank R., III Thompson; Dirk E. Burhans

    2003-01-01

    Our understanding of factors affecting nest predation and ability to mitigate high nest predation rates is hampered by a lack of information on the importance of various nest predator species in different habitats and landscapes. We identified predators of songbird nests in old-field and forest habitats in central Missouri, USA, with miniature video cameras. We used an...

  12. Geography of the circadian gene clock and photoperiodic response in western North American populations of the three-spined stickleback Gasterosteus aculeatus.

    PubMed

    O'Brien, C; Unruh, L; Zimmerman, C; Bradshaw, W E; Holzapfel, C M; Cresko, W A

    2013-03-01

    Controlled laboratory experiments were used to show that Oregon and Alaskan three-spined stickleback Gasterosteus aculeatus, collected from locations differing by 18° of latitude, exhibited no significant variation in length of the polyglutamine domain of the clock protein or in photoperiodic response within or between latitudes despite the fact that male and female G. aculeatus are photoperiodic at both latitudes. Hence, caution is urged when interpreting variation in the polyglutamine repeat (PolyQ) domain of the gene clock in the context of seasonal activities or in relationship to photoperiodism along geographical gradients. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

  13. The NUCLEAR FACTOR-CONSTANS complex antagonizes Polycomb repression to de-repress FLOWERING LOCUS T expression in response to inductive long days in Arabidopsis.

    PubMed

    Luo, Xiao; Gao, Zheng; Wang, Yizhong; Chen, Zhijuan; Zhang, Wenju; Huang, Jirong; Yu, Hao; He, Yuehui

    2018-07-01

    Many plants sense the seasonal cues, day length or photoperiod changes, to align the timing of the developmental transition to flowering with changing seasons for reproductive success. Inductive day lengths through the photoperiod pathway induce the expression of FLOWERING LOCUS T (FT) or FT relatives that encode a major mobile florigen to promote flowering. In Arabidopsis thaliana, under inductive long days the photoperiod pathway output CONSTANS (CO) accumulates toward the end of the day, and associates with the B and C subunits of Nuclear Factor Y (NF-Y) to form the NF-CO complex that acts to promote FT expression near dusk, whereas Polycomb group (PcG) proteins function to silence FT expression. How NF-CO acts to antagonize the function of PcG proteins to regulate FT expression remains unclear. Here, we show that the NF-CO complex bound to the proximal FT promoter, through chromatin looping, acts in concert with an NF-Y complex bound to a distal enhancer to reduce the levels of PcG proteins, including both Polycomb repressive complex 1 (PRC1) and PRC2 at the FT promoter, leading to a relieving of Polycomb silencing and thus FT de-repression near dusk. Thus, our study provides molecular insights on how the 'active' photoperiod pathway and the 'repressive' Polycomb silencing system interact to control temporal FT expression, conferring the long-day induction of flowering in Arabidopsis. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.

  14. Differential Expression of Glutamate Receptors in Avian Neural Pathways for Learned Vocalization

    PubMed Central

    WADA, KAZUHIRO; SAKAGUCHI, HIRONOBU; JARVIS, ERICH D.; HAGIWARA, MASATOSHI

    2008-01-01

    Learned vocalization, the substrate for human language, is a rare trait. It is found in three distantly related groups of birds—parrots, hummingbirds, and songbirds. These three groups contain cerebral vocal nuclei for learned vocalization not found in their more closely related vocal nonlearning relatives. Here, we cloned 21 receptor subunits/subtypes of all four glutamate receptor families (AMPA, kainate, NMDA, and metabotropic) and examined their expression in vocal nuclei of songbirds. We also examined expression of a subset of these receptors in vocal nuclei of hummingbirds and parrots, as well as in the brains of dove species as examples of close vocal nonlearning relatives. Among the 21 subunits/subtypes, 19 showed higher and/or lower prominent differential expression in songbird vocal nuclei relative to the surrounding brain subdivisions in which the vocal nuclei are located. This included relatively lower levels of all four AMPA subunits in lMAN, strikingly higher levels of the kainite subunit GluR5 in the robust nucleus of the arcopallium (RA), higher and lower levels respectively of the NMDA subunits NR2A and NR2B in most vocal nuclei and lower levels of the metabotropic group I subtypes (mGluR1 and -5) in most vocal nuclei and the group II subtype (mGluR2), showing a unique expression pattern of very low levels in RA and very high levels in HVC. The splice variants of AMPA subunits showed further differential expression in vocal nuclei. Some of the receptor subunits/subtypes also showed differential expression in hummingbird and parrot vocal nuclei. The magnitude of differential expression in vocal nuclei of all three vocal learners was unique compared with the smaller magnitude of differences found for nonvocal areas of vocal learners and vocal nonlearners. Our results suggest that evolution of vocal learning was accompanied by differential expression of a conserved gene family for synaptic transmission and plasticity in vocal nuclei. They also

  15. Seasonal ovulatory activity exists in tropical Creole female goats and Black Belly ewes subjected to a temperate photoperiod.

    PubMed

    Chemineau, Philippe; Daveau, Agnès; Cognié, Yves; Aumont, Gilles; Chesneau, Didier

    2004-08-27

    Seasonality of ovulatory activity is observed in European sheep and goat breeds, whereas tropical breeds show almost continuous ovulatory activity. It is not known if these tropical breeds are sensitive or not to temperate photoperiod. This study was therefore designed to determine whether tropical Creole goats and Black-Belly ewes are sensitive to temperate photoperiod. Two groups of adult females in each species, either progeny or directly born from imported embryos, were used and maintained in light-proof rooms under simulated temperate (8 to 16 h of light per day) or tropical (11 - 13 h) photoperiods. Ovulatory activity was determined by blood progesterone assays for more than two years. The experiment lasted 33 months in goats and 25 months in ewes. Marked seasonality of ovulatory activity appeared in the temperate group of Creole female goats. The percentage of female goats experiencing at least one ovulation per month dramatically decreased from May to September for the three years (0%, 27% and 0%, respectively). Tropical female goats demonstrated much less seasonality, as the percentage of goats experiencing at least one ovulation per month never went below 56%. These differences were significant. Both groups of temperate and tropical Black-Belly ewes experienced a marked seasonality in their ovulatory activity, with only a slightly significant difference between groups. The percentage of ewes experiencing at least one ovulation per month dropped dramatically in April and rose again in August (tropical ewes) or September (temperate ewes). The percentage of ewes experiencing at least one ovulation per month never went below 8% and 17% (for tropical and temperate ewes respectively) during the spring and summer months. An important seasonality in ovulatory activity of tropical Creole goats was observed when females were exposed to a simulated temperate photoperiod. An unexpected finding was that Black-Belly ewes and, to a lesser extent, Creole goats exposed to

  16. Seasonal ovulatory activity exists in tropical Creole female goats and Black Belly ewes subjected to a temperate photoperiod

    PubMed Central

    Chemineau, Philippe; Daveau, Agnès; Cognié, Yves; Aumont, Gilles; Chesneau, Didier

    2004-01-01

    Background Seasonality of ovulatory activity is observed in European sheep and goat breeds, whereas tropical breeds show almost continuous ovulatory activity. It is not known if these tropical breeds are sensitive or not to temperate photoperiod. This study was therefore designed to determine whether tropical Creole goats and Black-Belly ewes are sensitive to temperate photoperiod. Two groups of adult females in each species, either progeny or directly born from imported embryos, were used and maintained in light-proof rooms under simulated temperate (8 to 16 h of light per day) or tropical (11 – 13 h) photoperiods. Ovulatory activity was determined by blood progesterone assays for more than two years. The experiment lasted 33 months in goats and 25 months in ewes. Results Marked seasonality of ovulatory activity appeared in the temperate group of Creole female goats. The percentage of female goats experiencing at least one ovulation per month dramatically decreased from May to September for the three years (0%, 27% and 0%, respectively). Tropical female goats demonstrated much less seasonality, as the percentage of goats experiencing at least one ovulation per month never went below 56%. These differences were significant. Both groups of temperate and tropical Black-Belly ewes experienced a marked seasonality in their ovulatory activity, with only a slightly significant difference between groups. The percentage of ewes experiencing at least one ovulation per month dropped dramatically in April and rose again in August (tropical ewes) or September (temperate ewes). The percentage of ewes experiencing at least one ovulation per month never went below 8% and 17% (for tropical and temperate ewes respectively) during the spring and summer months. Conclusions An important seasonality in ovulatory activity of tropical Creole goats was observed when females were exposed to a simulated temperate photoperiod. An unexpected finding was that Black-Belly ewes and, to a

  17. Quantitative Tools for Examining the Vocalizations of Juvenile Songbirds

    PubMed Central

    Wellock, Cameron D.; Reeke, George N.

    2012-01-01

    The singing of juvenile songbirds is highly variable and not well stereotyped, a feature that makes it difficult to analyze with existing computational techniques. We present here a method suitable for analyzing such vocalizations, windowed spectral pattern recognition (WSPR). Rather than performing pairwise sample comparisons, WSPR measures the typicality of a sample against a large sample set. We also illustrate how WSPR can be used to perform a variety of tasks, such as sample classification, song ontogeny measurement, and song variability measurement. Finally, we present a novel measure, based on WSPR, for quantifying the apparent complexity of a bird's singing. PMID:22701474

  18. The neural dynamics of song syntax in songbirds

    NASA Astrophysics Data System (ADS)

    Jin, Dezhe

    2010-03-01

    Songbird is ``the hydrogen atom'' of the neuroscience of complex, learned vocalizations such as human speech. Songs of Bengalese finch consist of sequences of syllables. While syllables are temporally stereotypical, syllable sequences can vary and follow complex, probabilistic syntactic rules, which are rudimentarily similar to grammars in human language. Songbird brain is accessible to experimental probes, and is understood well enough to construct biologically constrained, predictive computational models. In this talk, I will discuss the structure and dynamics of neural networks underlying the stereotypy of the birdsong syllables and the flexibility of syllable sequences. Recent experiments and computational models suggest that a syllable is encoded in a chain network of projection neurons in premotor nucleus HVC (proper name). Precisely timed spikes propagate along the chain, driving vocalization of the syllable through downstream nuclei. Through a computational model, I show that that variable syllable sequences can be generated through spike propagations in a network in HVC in which the syllable-encoding chain networks are connected into a branching chain pattern. The neurons mutually inhibit each other through the inhibitory HVC interneurons, and are driven by external inputs from nuclei upstream of HVC. At a branching point that connects the final group of a chain to the first groups of several chains, the spike activity selects one branch to continue the propagation. The selection is probabilistic, and is due to the winner-take-all mechanism mediated by the inhibition and noise. The model predicts that the syllable sequences statistically follow partially observable Markov models. Experimental results supporting this and other predictions of the model will be presented. We suggest that the syntax of birdsong syllable sequences is embedded in the connection patterns of HVC projection neurons.

  19. Maternal transfer of mercury to songbird eggs.

    PubMed

    Ackerman, Joshua T; Hartman, C Alex; Herzog, Mark P

    2017-11-01

    We evaluated the maternal transfer of mercury to eggs in songbirds, determined whether this relationship differed between songbird species, and developed equations for predicting mercury concentrations in eggs from maternal blood. We sampled blood and feathers from 44 house wren (Troglodytes aedon) and 34 tree swallow (Tachycineta bicolor) mothers and collected their full clutches (n = 476 eggs) within 3 days of clutch completion. Additionally, we sampled blood and feathers from 53 tree swallow mothers and randomly collected one egg from their clutches (n = 53 eggs) during mid to late incubation (6-10 days incubated) to evaluate whether the relationship varied with the timing of sampling the mother's blood. Mercury concentrations in eggs were positively correlated with mercury concentrations in maternal blood sampled at (1) the time of clutch completion for both house wrens (R 2  = 0.97) and tree swallows (R 2  = 0.97) and (2) during mid to late incubation for tree swallows (R 2  = 0.71). The relationship between mercury concentrations in eggs and maternal blood did not differ with the stage of incubation when maternal blood was sampled. Importantly, the proportion of mercury transferred from mothers to their eggs decreased substantially with increasing blood mercury concentrations in tree swallows, but increased slightly with increasing blood mercury concentrations in house wrens. Additionally, the proportion of mercury transferred to eggs at the same maternal blood mercury concentration differed between species. Specifically, tree swallow mothers transferred 17%-107% more mercury to their eggs than house wren mothers over the observed mercury concentrations in maternal blood (0.15-1.92 μg/g ww). In contrast, mercury concentrations in eggs were not correlated with those in maternal feathers and, likewise, mercury concentrations in maternal blood were not correlated with those in feathers (all R 2  < 0.01). We provide equations to translate mercury

  20. Maternal transfer of mercury to songbird eggs

    USGS Publications Warehouse

    Ackerman, Joshua T.; Hartman, C. Alex; Herzog, Mark

    2017-01-01

    We evaluated the maternal transfer of mercury to eggs in songbirds, determined whether this relationship differed between songbird species, and developed equations for predicting mercury concentrations in eggs from maternal blood. We sampled blood and feathers from 44 house wren (Troglodytes aedon) and 34 tree swallow (Tachycineta bicolor) mothers and collected their full clutches (n = 476 eggs) within 3 days of clutch completion. Additionally, we sampled blood and feathers from 53 tree swallow mothers and randomly collected one egg from their clutches (n = 53 eggs) during mid to late incubation (6–10 days incubated) to evaluate whether the relationship varied with the timing of sampling the mother's blood. Mercury concentrations in eggs were positively correlated with mercury concentrations in maternal blood sampled at (1) the time of clutch completion for both house wrens (R2 = 0.97) and tree swallows (R2 = 0.97) and (2) during mid to late incubation for tree swallows (R2 = 0.71). The relationship between mercury concentrations in eggs and maternal blood did not differ with the stage of incubation when maternal blood was sampled. Importantly, the proportion of mercury transferred from mothers to their eggs decreased substantially with increasing blood mercury concentrations in tree swallows, but increased slightly with increasing blood mercury concentrations in house wrens. Additionally, the proportion of mercury transferred to eggs at the same maternal blood mercury concentration differed between species. Specifically, tree swallow mothers transferred 17%–107% more mercury to their eggs than house wren mothers over the observed mercury concentrations in maternal blood (0.15–1.92 μg/g ww). In contrast, mercury concentrations in eggs were not correlated with those in maternal feathers and, likewise, mercury concentrations in maternal blood were not correlated with those in feathers (all R2 < 0.01). We provide equations to translate mercury

  1. Statistical learning in songbirds: from self-tutoring to song culture.

    PubMed

    Fehér, Olga; Ljubičić, Iva; Suzuki, Kenta; Okanoya, Kazuo; Tchernichovski, Ofer

    2017-01-05

    At the onset of vocal development, both songbirds and humans produce variable vocal babbling with broadly distributed acoustic features. Over development, these vocalizations differentiate into the well-defined, categorical signals that characterize adult vocal behaviour. A broadly distributed signal is ideal for vocal exploration, that is, for matching vocal production to the statistics of the sensory input. The developmental transition to categorical signals is a gradual process during which the vocal output becomes differentiated and stable. But does it require categorical input? We trained juvenile zebra finches with playbacks of their own developing song, produced just a few moments earlier, updated continuously over development. Although the vocalizations of these self-tutored (ST) birds were initially broadly distributed, birds quickly developed categorical signals, as fast as birds that were trained with a categorical, adult song template. By contrast, siblings of those birds that received no training (isolates) developed phonological categories much more slowly and never reached the same level of category differentiation as their ST brothers. Therefore, instead of simply mirroring the statistical properties of their sensory input, songbirds actively transform it into distinct categories. We suggest that the early self-generation of phonological categories facilitates the establishment of vocal culture by making the song easier to transmit at the micro level, while promoting stability of shared vocabulary at the group level over generations.This article is part of the themed issue 'New frontiers for statistical learning in the cognitive sciences'. © 2016 The Authors.

  2. Male songbird indicates body size with low-pitched advertising songs.

    PubMed

    Hall, Michelle L; Kingma, Sjouke A; Peters, Anne

    2013-01-01

    Body size is a key sexually selected trait in many animal species. If size imposes a physical limit on the production of loud low-frequency sounds, then low-pitched vocalisations could act as reliable signals of body size. However, the central prediction of this hypothesis--that the pitch of vocalisations decreases with size among competing individuals--has limited support in songbirds. One reason could be that only the lowest-frequency components of vocalisations are constrained, and this may go unnoticed when vocal ranges are large. Additionally, the constraint may only be apparent in contexts when individuals are indeed advertising their size. Here we explicitly consider signal diversity and performance limits to demonstrate that body size limits song frequency in an advertising context in a songbird. We show that in purple-crowned fairy-wrens, Malurus coronatus coronatus, larger males sing lower-pitched low-frequency advertising songs. The lower frequency bound of all advertising song types also has a significant negative relationship with body size. However, the average frequency of all their advertising songs is unrelated to body size. This comparison of different approaches to the analysis demonstrates how a negative relationship between body size and song frequency can be obscured by failing to consider signal design and the concept of performance limits. Since these considerations will be important in any complex communication system, our results imply that body size constraints on low-frequency vocalisations could be more widespread than is currently recognised.

  3. Retirement investment theory explains patterns in songbird nest-site choice

    USGS Publications Warehouse

    Streby, Henry M.; Refsnider, Jeanine M.; Peterson, Sean M.; Andersen, David E.

    2014-01-01

    When opposing evolutionary selection pressures act on a behavioural trait, the result is often stabilizing selection for an intermediate optimal phenotype, with deviations from the predicted optimum attributed to tracking a moving target, development of behavioural syndromes or shifts in riskiness over an individual's lifetime. We investigated nest-site choice by female golden-winged warblers, and the selection pressures acting on that choice by two fitness components, nest success and fledgling survival. We observed strong and consistent opposing selection pressures on nest-site choice for maximizing these two fitness components, and an abrupt, within-season switch in the fitness component birds prioritize via nest-site choice, dependent on the time remaining for additional nesting attempts. We found that females consistently deviated from the predicted optimal behaviour when choosing nest sites because they can make multiple attempts at one fitness component, nest success, but only one attempt at the subsequent component, fledgling survival. Our results demonstrate a unique natural strategy for balancing opposing selection pressures to maximize total fitness. This time-dependent switch from high to low risk tolerance in nest-site choice maximizes songbird fitness in the same way a well-timed switch in human investor risk tolerance can maximize one's nest egg at retirement. Our results also provide strong evidence for the adaptive nature of songbird nest-site choice, which we suggest has been elusive primarily due to a lack of consideration for fledgling survival.

  4. Mechanisms underlying the social enhancement of vocal learning in songbirds.

    PubMed

    Chen, Yining; Matheson, Laura E; Sakata, Jon T

    2016-06-14

    Social processes profoundly influence speech and language acquisition. Despite the importance of social influences, little is known about how social interactions modulate vocal learning. Like humans, songbirds learn their vocalizations during development, and they provide an excellent opportunity to reveal mechanisms of social influences on vocal learning. Using yoked experimental designs, we demonstrate that social interactions with adult tutors for as little as 1 d significantly enhanced vocal learning. Social influences on attention to song seemed central to the social enhancement of learning because socially tutored birds were more attentive to the tutor's songs than passively tutored birds, and because variation in attentiveness and in the social modulation of attention significantly predicted variation in vocal learning. Attention to song was influenced by both the nature and amount of tutor song: Pupils paid more attention to songs that tutors directed at them and to tutors that produced fewer songs. Tutors altered their song structure when directing songs at pupils in a manner that resembled how humans alter their vocalizations when speaking to infants, that was distinct from how tutors changed their songs when singing to females, and that could influence attention and learning. Furthermore, social interactions that rapidly enhanced learning increased the activity of noradrenergic and dopaminergic midbrain neurons. These data highlight striking parallels between humans and songbirds in the social modulation of vocal learning and suggest that social influences on attention and midbrain circuitry could represent shared mechanisms underlying the social modulation of vocal learning.

  5. Retirement investment theory explains patterns in songbird nest-site choice

    PubMed Central

    Streby, Henry M.; Refsnider, Jeanine M.; Peterson, Sean M.; Andersen, David E.

    2014-01-01

    When opposing evolutionary selection pressures act on a behavioural trait, the result is often stabilizing selection for an intermediate optimal phenotype, with deviations from the predicted optimum attributed to tracking a moving target, development of behavioural syndromes or shifts in riskiness over an individual's lifetime. We investigated nest-site choice by female golden-winged warblers, and the selection pressures acting on that choice by two fitness components, nest success and fledgling survival. We observed strong and consistent opposing selection pressures on nest-site choice for maximizing these two fitness components, and an abrupt, within-season switch in the fitness component birds prioritize via nest-site choice, dependent on the time remaining for additional nesting attempts. We found that females consistently deviated from the predicted optimal behaviour when choosing nest sites because they can make multiple attempts at one fitness component, nest success, but only one attempt at the subsequent component, fledgling survival. Our results demonstrate a unique natural strategy for balancing opposing selection pressures to maximize total fitness. This time-dependent switch from high to low risk tolerance in nest-site choice maximizes songbird fitness in the same way a well-timed switch in human investor risk tolerance can maximize one's nest egg at retirement. Our results also provide strong evidence for the adaptive nature of songbird nest-site choice, which we suggest has been elusive primarily due to a lack of consideration for fledgling survival. PMID:24403320

  6. Male Songbird Indicates Body Size with Low-Pitched Advertising Songs

    PubMed Central

    Hall, Michelle L.; Kingma, Sjouke A.; Peters, Anne

    2013-01-01

    Body size is a key sexually selected trait in many animal species. If size imposes a physical limit on the production of loud low-frequency sounds, then low-pitched vocalisations could act as reliable signals of body size. However, the central prediction of this hypothesis – that the pitch of vocalisations decreases with size among competing individuals – has limited support in songbirds. One reason could be that only the lowest-frequency components of vocalisations are constrained, and this may go unnoticed when vocal ranges are large. Additionally, the constraint may only be apparent in contexts when individuals are indeed advertising their size. Here we explicitly consider signal diversity and performance limits to demonstrate that body size limits song frequency in an advertising context in a songbird. We show that in purple-crowned fairy-wrens, Malurus coronatus coronatus, larger males sing lower-pitched low-frequency advertising songs. The lower frequency bound of all advertising song types also has a significant negative relationship with body size. However, the average frequency of all their advertising songs is unrelated to body size. This comparison of different approaches to the analysis demonstrates how a negative relationship between body size and song frequency can be obscured by failing to consider signal design and the concept of performance limits. Since these considerations will be important in any complex communication system, our results imply that body size constraints on low-frequency vocalisations could be more widespread than is currently recognised. PMID:23437221

  7. Differential FoxP2 and FoxP1 expression in a vocal learning nucleus of the developing budgerigar

    PubMed Central

    Whitney, Osceola; Voyles, Tawni; Hara, Erina; Chen, Qianqian; White, Stephanie A.; Wright, Timothy F.

    2014-01-01

    The forkhead domain FOXP2 and FOXP1 transcription factors are implicated in several cognitive disorders with language deficits, notably autism, and thus play a central role in learned vocal motor behavior in humans. Although a similar role for FoxP2 and FoxP1 is proposed for other vertebrate species, including songbirds, the neurodevelopmental expression of these genes are unknown in a species with lifelong vocal learning abilities. Like humans, budgerigars (Melopsittacus undulatus) learn new vocalizations throughout their entire lifetime. Like songbirds, budgerigars have distinct brain nuclei for vocal learning, which include the magnocellular nucleus of the medial striatum (MMSt), a basal ganglia region that is considered developmentally and functionally analogous to Area X in songbirds. Here we used in situ hybridization and immunohistochemistry to investigate FoxP2 and FoxP1 expression in the MMSt of juvenile and adult budgerigars. We found FoxP2 mRNA and protein expression levels in the MMSt that were lower than the surrounding striatum throughout development and adulthood. In contrast, FoxP1 mRNA and protein had an elevated MMSt/striatum expression ratio as birds matured, regardless of their sex. These results show that life-long vocal plasticity in budgerigars is associated with persistent low-level FoxP2 expression in the budgerigar MMSt, and suggests the possibility that FoxP1 plays an organizational role in the neurodevelopment of vocal motor circuitry. Thus, developmental regulation of the FoxP2 and FoxP1 genes in the basal ganglia appears essential for vocal mimicry in a range of species that possess this relatively rare trait. PMID:25407828

  8. Differential FoxP2 and FoxP1 expression in a vocal learning nucleus of the developing budgerigar.

    PubMed

    Whitney, Osceola; Voyles, Tawni; Hara, Erina; Chen, Qianqian; White, Stephanie A; Wright, Timothy F

    2015-07-01

    The forkhead domain FOXP2 and FOXP1 transcription factors are implicated in several cognitive disorders with language deficits, notably autism, and thus play a central role in learned vocal motor behavior in humans. Although a similar role for FoxP2 and FoxP1 is proposed for other vertebrate species, including songbirds, the neurodevelopmental expression of these genes are unknown in a species with lifelong vocal learning abilities. Like humans, budgerigars (Melopsittacus undulatus) learn new vocalizations throughout their entire lifetime. Like songbirds, budgerigars have distinct brain nuclei for vocal learning, which include the magnocellular nucleus of the medial striatum (MMSt), a basal ganglia region that is considered developmentally and functionally analogous to Area X in songbirds. Here, we used in situ hybridization and immunohistochemistry to investigate FoxP2 and FoxP1 expression in the MMSt of juvenile and adult budgerigars. We found FoxP2 mRNA and protein expression levels in the MMSt that were lower than the surrounding striatum throughout development and adulthood. In contrast, FoxP1 mRNA and protein had an elevated MMSt/striatum expression ratio as birds matured, regardless of their sex. These results show that life-long vocal plasticity in budgerigars is associated with persistent low-level FoxP2 expression in the budgerigar MMSt, and suggests the possibility that FoxP1 plays an organizational role in the neurodevelopment of vocal motor circuitry. Thus, developmental regulation of the FoxP2 and FoxP1 genes in the basal ganglia appears essential for vocal mimicry in a range of species that possess this relatively rare trait. © 2014 Wiley Periodicals, Inc.

  9. Crosstalks between kisspeptin neurons and somatostatin neurons are not photoperiod dependent in the ewe hypothalamus.

    PubMed

    Dufourny, Laurence; Lomet, Didier

    2017-12-01

    Seasonal reproduction is under the control of gonadal steroid feedback, itself synchronized by day-length or photoperiod. As steroid action on GnRH neurons is mostly indirect and therefore exerted through interneurons, we looked for neuroanatomical interactions between kisspeptin (KP) neurons and somatostatin (SOM) neurons, two populations targeted by sex steroids, in three diencephalic areas involved in the central control of ovulation and/or sexual behavior: the arcuate nucleus (ARC), the preoptic area (POA) and the ventrolateral part of the ventromedial hypothalamus (VMHvl). KP is the most potent secretagogue of GnRH secretion while SOM has been shown to centrally inhibit LH pulsatile release. Notably, hypothalamic contents of these two neuropeptides vary with photoperiod in specific seasonal species. Our hypothesis is that SOM inhibits KP neuron activity and therefore indirectly modulate GnRH release and that this effect may be seasonally regulated. We used sections from ovariectomized estradiol-replaced ewes killed after photoperiodic treatment mimicking breeding or anestrus season. We performed triple immunofluorescent labeling to simultaneously detect KP, SOM and synapsin, a marker for synaptic vesicles. Sections from the POA and from the mediobasal hypothalamus were examined using a confocal microscope. Randomly selected KP or SOM neurons were observed in the POA and ARC. SOM neurons were also observed in the VMHvl. In both the ARC and POA, nearly all KP neurons presented numerous SOM contacts. SOM neurons presented KP terminals more frequently in the ARC than in the POA and VMHvl. Quantitative analysis failed to demonstrate major seasonal variations of KP and SOM interactions. Our data suggest a possible inhibitory action of SOM on all KP neurons in both photoperiodic statuses. On the other hand, the physiological significance of KP modulation of SOM neuron activity and vice versa remain to be determined. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. White-tailed deer (Odocoileus virginianus) predation on grassland songbird nestlings

    USGS Publications Warehouse

    Pietz, Pamela J.; Granfors, Diane A.

    2000-01-01

    White-tailed deer (Odocoileus virginianus) were videotaped depredating four songbird nests in grassland habitats in southeastern and northcentral North Dakota, 1996-1999. Deer ate two Savannah sparrow (Passerculus sandwichensis), two grasshopper sparrow (Ammodramus savannarum), one clay-colored sparrow (Spizella pallida), one red-winged blackbird (Agelaius phoeniceus) and three brown-headed cowbird (Molothrus ater) nestlings. Deer removed nestlings quickly (5-19 sec/nest) at night (22:00 to 05:17 Central Daylight Time) and left no evidence of predation. Although probably opportunistic, deer predations clearly were deliberate and likely are more common than generally believed.

  11. Simulated Seasonal Photoperiods and Fluctuating Temperatures Have Limited Effects on Blood Feeding and Life History in Aedes triseriatus (Diptera: Culicidae)

    PubMed Central

    Westby, K. M.

    2015-01-01

    Biotic and abiotic factors change seasonally and impact life history in temperate-zone ectotherms. Temperature and photoperiod are factors that change in predictable ways. Most studies testing for effects of temperature on vectors use constant temperatures and ignore potential correlated effects of photoperiod. In two experiments, we tested for effects of larval rearing environments creating ecologically relevant temperatures and photoperiods simulating early and late season conditions (June and August), or constant temperatures (cool and warm) with the June or August photoperiods, respectively. We determined effects on survivorship, development, size, and a composite performance index in a temperate-zone population of Aedes triseriatus (Say). We followed cohorts of resulting females, all held under the same environmental conditions, to assess carry-over effects of rearing conditions for larvae on longevity, blood feeding, and egg production. Larval survivorship was affected by treatment in one experiment. Development time was greater in the June and cool treatments, but the constant and fluctuating temperatures did not differ. Significantly larger mosquitoes were produced in fluctuating versus constant temperature treatments. There were no significant treatment effects on the composite performance index. Adult female longevity was lower after rearing at constant versus fluctuating temperature, but there was no difference between June and August, nor did size affect longevity. There was no effect of treatments on blood feeding and a limited effect on egg production. We conclude that seasonal temperatures and photoperiods during development have limited effects on this population of A. triseriatus and find little evidence of strong effects of fluctuating versus constant temperatures. PMID:26336255

  12. Extraretinal Light Perception in the Sparrow, III: The Eyes Do Not Participate in Photoperiodic Photoreception*

    PubMed Central

    Menaker, Michael; Roberts, Richard; Elliott, Jeffrey; Underwood, Herbert

    1970-01-01

    Photoperiodic control of testis growth in Passer domesticus (house sparrow) is mediated entirely by extraretinal photoreceptors in the brain. The eyes do not participate in photoperiodically significant photoreception. Removal of the pineal organ does not affect either the response to light or, to a first approximation, the process of recrudescence. The intensity of light reaching the retina and that reaching the extraretinal photoreceptor were varied independently. This technique will make it possible to study brain photoreception in species of birds that will not tolerate blinding. Extreme caution is necessary in the interpretation of brain lesion experiments in which reproductive function is modified, since photoreception by brain receptors of unknown anatomical location affects testicular state. PMID:5272320

  13. Predation-related costs and benefits of conspecific attraction in songbirds--an agent-based approach.

    PubMed

    Szymkowiak, Jakub; Kuczyński, Lechosław

    2015-01-01

    Songbirds that follow a conspecific attraction strategy in the habitat selection process prefer to settle in habitat patches already occupied by other individuals. This largely affects the patterns of their spatio-temporal distribution and leads to clustered breeding. Although making informed settlement decisions is expected to be beneficial for individuals, such territory clusters may potentially provide additional fitness benefits (e.g., through the dilution effect) or costs (e.g., possibly facilitating nest localization if predators respond functionally to prey distribution). Thus, we hypothesized that the fitness consequences of following a conspecific attraction strategy may largely depend on the composition of the predator community. We developed an agent-based model in which we simulated the settling behavior of birds that use a conspecific attraction strategy and breed in a multi-predator landscape with predators that exhibited different foraging strategies. Moreover, we investigated whether Bayesian updating of prior settlement decisions according to the perceived predation risk may improve the fitness of birds that rely on conspecific cues. Our results provide evidence that the fitness consequences of conspecific attraction are predation-related. We found that in landscapes dominated by predators able to respond functionally to prey distribution, clustered breeding led to fitness costs. However, this cost could be reduced if birds performed Bayesian updating of prior settlement decisions and perceived nesting with too many neighbors as a threat. Our results did not support the hypothesis that in landscapes dominated by incidental predators, clustered breeding as a byproduct of conspecific attraction provides fitness benefits through the dilution effect. We suggest that this may be due to the spatial scale of songbirds' aggregative behavior. In general, we provide evidence that when considering the fitness consequences of conspecific attraction for

  14. Social modulation of learned behavior by dopamine in the basal ganglia: insights from songbirds.

    PubMed

    Leblois, Arthur

    2013-06-01

    Dysfunction of the dopaminergic system leads to motor, cognitive, and motivational symptoms in brain disorders such as Parkinson's disease. The basal ganglia (BG) are involved in sensorimotor learning and receive a strong dopaminergic signal, shown to play an important role in social interactions. The function of the dopaminergic input to the BG in the integration of social cues during sensorimotor learning remains however largely unexplored. Songbirds use learned vocalizations to communicate during courtship and aggressive behaviors. Like language learning in humans, song learning strongly depends on social interactions. In songbirds, a specialized BG-thalamo-cortical loop devoted to song is particularly tractable for elucidating the signals carried by dopamine in the BG, and the function of dopamine signaling in mediating social cues during skill learning and execution. Here, I review experimental findings uncovering the physiological effects and function of the dopaminergic signal in the songbird BG, in light of our knowledge of the BG-dopamine interactions in mammals. Interestingly, the compact nature of the striato-pallidal circuits in birds led to new insight on the physiological effects of the dopaminergic input on the BG network as a whole. In singing birds, D1-like receptor agonist and antagonist can modulate the spectral variability of syllables bi-directionally, suggesting that social context-dependent changes in spectral variability are triggered by dopaminergic input through D1-like receptors. As variability is crucial for exploration during motor learning, but must be reduced after learning to optimize performance, I propose that, the dopaminergic input to the BG could be responsible for the social-dependent regulation of the exploration/exploitation balance in birdsong, and possibly in learned skills in other vertebrates. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Photoperiod-H1 (Ppd-H1) Controls Leaf Size.

    PubMed

    Digel, Benedikt; Tavakol, Elahe; Verderio, Gabriele; Tondelli, Alessandro; Xu, Xin; Cattivelli, Luigi; Rossini, Laura; von Korff, Maria

    2016-09-01

    Leaf size is a major determinant of plant photosynthetic activity and biomass; however, it is poorly understood how leaf size is genetically controlled in cereal crop plants like barley (Hordeum vulgare). We conducted a genome-wide association scan for flowering time, leaf width, and leaf length in a diverse panel of European winter cultivars grown in the field and genotyped with a single-nucleotide polymorphism array. The genome-wide association scan identified PHOTOPERIOD-H1 (Ppd-H1) as a candidate gene underlying the major quantitative trait loci for flowering time and leaf size in the barley population. Microscopic phenotyping of three independent introgression lines confirmed the effect of Ppd-H1 on leaf size. Differences in the duration of leaf growth and consequent variation in leaf cell number were responsible for the leaf size differences between the Ppd-H1 variants. The Ppd-H1-dependent induction of the BARLEY MADS BOX genes BM3 and BM8 in the leaf correlated with reductions in leaf size and leaf number. Our results indicate that leaf size is controlled by the Ppd-H1- and photoperiod-dependent progression of plant development. The coordination of leaf growth with flowering may be part of a reproductive strategy to optimize resource allocation to the developing inflorescences and seeds. © 2016 American Society of Plant Biologists. All rights reserved.

  16. Assessing visual requirements for social context-dependent activation of the songbird song system

    PubMed Central

    Hara, Erina; Kubikova, Lubica; Hessler, Neal A.; Jarvis, Erich D.

    2008-01-01

    Social context has been shown to have a profound influence on brain activation in a wide range of vertebrate species. Best studied in songbirds, when males sing undirected song, the level of neural activity and expression of immediate early genes (IEGs) in several song nuclei is dramatically higher or lower than when they sing directed song to other birds, particularly females. This differential social context-dependent activation is independent of auditory input and is not simply dependent on the motor act of singing. These findings suggested that the critical sensory modality driving social context-dependent differences in the brain could be visual cues. Here, we tested this hypothesis by examining IEG activation in song nuclei in hemispheres to which visual input was normal or blocked. We found that covering one eye blocked visually induced IEG expression throughout both contralateral visual pathways of the brain, and reduced activation of the contralateral ventral tegmental area, a non-visual midbrain motivation-related area affected by social context. However, blocking visual input had no effect on the social context-dependent activation of the contralateral song nuclei during female-directed singing. Our findings suggest that individual sensory modalities are not direct driving forces for the social context differences in song nuclei during singing. Rather, these social context differences in brain activation appear to depend more on the general sense that another individual is present. PMID:18826930

  17. Do photoperiod and endocrine disruptor 4-tert-octylphenol effect on spermatozoa of bank vole (Clethrionomys glareolus)?

    PubMed

    Kotula-Balak, Malgorzata; Grzmil, Pawel; Chojnacka, Katarzyna; Andryka, Katarzyna; Bilinska, Barbara

    2014-05-15

    Photoperiod is an environmental signal that controls physiology and behavior of all organisms. Bank voles, which are seasonal breeders, are stimulated to reproduce by the long photoperiod associated with spring and summer. To date, physiology of bank vole spermatozoa has not been explored, although they constitute an interesting model for examining the relationship between photoperiod and xenoestrogen on spermatozoa function. In an attempt to evaluate the acute effect of 4-tert-octylphenol (OP) an in vitro system was used. Spermatozoa isolated from the cauda epididymidies of long-day (LD; 18 h light: 6 h darkness) and short-day (SD; 6 h light: 18 h darkness) bank voles were treated with two OP concentrations (10(-4) M and 10(-8)M, respectively). OP-treated spermatozoa were used for the examination of motility parameters (computer-assisted semen analyzer CEROS), acrosome integrity (Commassie blue staining), cAMP production (immunoenzymatic assay) and cell viability (flow-cytometry analysis). The study revealed the photoperiod-dependent effect of short OP-treatment on motility parameters of vole spermatozoa. In LD spermatozoa, an increase of velocities: (curvilinear velocity [VCL], average path velocity [VAP] straight line velocity [VSL]) and head activity (amplitude of the lateral head displacement, [ALH]) was found. Interestingly, in SD spermatozoa opposite effect on VCL, VAP, VSL and ALH was observed, however only after treatment with 10(-4)M OP. The dose-dependent influence of OP upon acrosome integrity, as well as cAMP levels, in relation to the reproductive status of voles was observed. Moreover, OP exposure affected spermatozoa morphology rather than spermatozoa viability. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Both Low Temperature and Shorter Duration of Food Availability Delay Testicular Regression and Affect the Daily Cycle in Body Temperature in a Songbird.

    PubMed

    Dawson, Alistair

    Photoperiodic control of reproduction in birds is based on two processes, a positive effect leading to gonadal maturation and an inhibitory effect subsequently inducing regression. Nonphotoperiodic cues can modulate photoperiodic control, particularly the inhibitory process. In previous studies of common starlings (Sturnus vulgaris), (1) restriction of food availability to 8 h after dawn had little effect on testicular maturation but dramatically delayed subsequent regression and (2) lower ambient temperature also had little effect during maturation but delayed regression. Could the effects of food restriction and temperature share a common underlying mechanism? Four groups of starlings were kept on a simulated natural cycle in photoperiod in a 2 × 2 factorial experimental design. Two groups were held under an ambient temperature of 16°C, and the other two were held under 6°C. One of each of these groups had food provided ad lib., and in the other two groups access to food was denied 7 h after dawn. In both the ad lib. food groups and the food-restricted groups, lower temperature had little effect on testicular maturation but delayed subsequent regression and molt. In both the 16°C groups and the 6°C groups, food restriction had no effect on testicular maturation but delayed regression and molt. The daily cycle in body temperature was recorded in all groups when the photoperiod had reached 12L∶12D, the photoperiod at which regression is initiated. In both 6°C groups, nighttime body temperature was lower than in the 16°C groups, a characteristic of shorter photoperiods. In the two ad lib. food groups high daytime temperature was maintained until dusk, whereas in the two food-restricted groups body temperature began to decrease after food withdrawal. Thus, both lower temperature and food restriction delayed regression, as if the photoperiod was shorter than it actually was, and both resulted in daily cycles in body temperature that reflected cycles under

  19. Invasion of an exotic forb impacts reproductive success and site fidelity of a migratory songbird

    Treesearch

    Yvette Katina Ortega; Kevin Scot McKelvey; Diana Lee Six

    2006-01-01

    Although exotic plant invasions threaten natural systems worldwide, we know little about the specific ecological impacts of invaders, including the magnitude of effects and underlying mechanisms. Exotic plants are likely to impact higher trophic levels when they overrun native plant communities, affecting habitat quality for breeding songbirds by altering food...

  20. Species-specific variation in nesting and postfledging resource selection for two forest breeding migrant songbirds

    Treesearch

    Julianna M. A. Jenkins; Frank R. Thompson; John Faaborg; Andrew J. Kroll

    2017-01-01

    Habitat selection is a fundamental component of community ecology, population ecology, and evolutionary biology and can be especially important to species with complex annual habitat requirements, such as migratory birds. Resource preferences on the breeding grounds may change during the postfledging period for migrant songbirds, however, the degree to which selection...

  1. Contrasting nest survival patterns for ducks and songbirds in northern mixed-grass prairie

    USGS Publications Warehouse

    Grant, Todd; Shaffer, Terry L.; Madden, Elizabeth M.; Nenneman, Melvin P.

    2017-01-01

    Management actions intended to protect or improve habitat for ducks may benefit grassland-nesting passerines, but scant information is available to explore this assumption. During 1998–2003, we examined nest survival of ducks and songbirds to determine whether effects of prescribed fire and other habitat features (e.g., shrub cover and distance to habitat edges) were similar for ducks and passerines breeding in North Dakota. We used the logistic-exposure method to estimate survival of duck and songbird nests (n = 3,171). We used an information-theoretic approach to identify factors that most influenced nest survival. Patterns of nest survival were markedly different between taxonomic groups. For ducks, nest survival was greater during the first postfire nesting season (daily survival rate [DSR] = 0.957, 85% CI = 0.951–0.963), relative to later postfire nesting seasons (DSR = 0.946, 85% CI = 0.942–0.950). Furthermore duck nest survival and nest densities were inversely related. Duck nest survival also was greater as shrub cover decreased and as distance from cropland and wetland edges increased. Passerines had lower nest survival during the first postfire nesting season (DSR = 0.934, 85% CI = 0.924–0.944), when densities also were low compared to subsequent postfire nesting seasons (DSR = 0.947, 85% CI = 0.944–0.950). Parasitism by brown-headed cowbirds (Molothrus ater) reduced passerine nest survival and this effect was more pronounced during the first postfire nesting season compared to subsequent nesting seasons. Passerine nest survival was greater as shrub cover decreased and perhaps for more concealed nests. Duck and songbird nest survival rates were not correlated during this study and for associated studies that examined additional variables using the same dataset, suggesting that different mechanisms influenced their survival. Based on our results, ducks should not be considered direct surrogates for passerines

  2. The polyamines of Xanthium strumarium and their response to photoperiod.

    PubMed

    Hamasaki, N; Galston, A W

    1990-01-01

    Flowering plants of Xanthium strumarium L., grown in 8 h photoperiods, were analysed for polyamines. Putrescine, spermidine and spermine were found throughout the plant in three forms: (a) as free polyamines; (b) conjugates soluble in 5% trichloracetic acid (TCA); and (c) bound to the TCA-insoluble precipitate. On a fresh weight basis, total polyamines are most abundant in young leaves and buds, especially flower buds. Spermidine predominates in the free polyamine fractions, while spermine is dominant in the conjugated fraction. Transfer of vegetative plants from 16 h photoperiods to 1, 2, 3, or 4 inductive cycles (8 h light + 16 h uninterrupted dark) caused rapid and marked changes in the polyamine titer of the leaves and ultimately, floral initiation. The titer of free putrescine per mg protein declined progressively with induction in all leaf sizes, while the titers of free spermidine and spermine rose during days 2 and 3 in small and expanding leaves. Conjugated putrescine, spermidine and spermine rose sharply after only 1 inductive cycle, especially in small and expanding leaves, and maintained the higher level for at least several cycles. In plants given 4 inductive cycles, buds harvested after 4 additional days had sharply elevated levels of conjugated polyamines, especially spermine, on a protein basis.

  3. Coupling Developmental Physiology, Photoperiod, and Temperature to Model Phenology and Dynamics of an Invasive Heteropteran, Halyomorpha halys

    PubMed Central

    Nielsen, Anne L.; Chen, Shi; Fleischer, Shelby J.

    2016-01-01

    We developed an agent-based stochastic model expressing stage-specific phenology and population dynamics for an insect species across geographic regions. We used the invasive pentatomid, Halyomorpha halys, as the model organism because gaps in knowledge exist regarding its developmental physiology, it is expanding its global distribution, and it is of significant economic importance. Model predictions were compared against field observations over 3 years, and the parameter set that enables the largest population growth was applied to eight locations over 10 years, capturing the variation in temperature and photoperiod profiles of significant horticultural crop production that could be affected by H. halys in the US. As a species that overwinters as adults, critical photoperiod significantly impacted H. halys seasonality and population size through its influence on diapause termination and induction, and this may impact other insects with similar life-histories. Photoperiod and temperature interactions influenced life stage synchrony among years, resulting in an order of magnitude difference, for occurrence of key life stages. At all locations, there was a high degree of overlap among life stages and generation. Although all populations produced F2 adults and thus could be characterized as bivoltine, the size and relative contribution of each generation to the total, or overwintering, adult population also varied dramatically. In about half of the years in two locations (Geneva, NY and Salem, OR), F1 adults comprised half or more of the adult population at the end of the year. Yearly degree-day accumulation was a significant covariate influencing variation in population growth, and average maximum adult population size varied by 10-fold among locations. Average final population growth was positive (Asheville, NC, Homestead, FL, Davis, CA) or marginal (Geneva, NY, Bridgeton, NJ, Salem, OR, Riverside, CA), but was negative in one location (Wenatchee WA) due to cooler

  4. Photosynthetic photon flux, photoperiod, and temperature effects on emissions of (Z)-3-hexenal, (Z)-3-hexenol, and (Z)-3-hexenyl acetate from lettuce

    NASA Technical Reports Server (NTRS)

    Charron, C. S.; Cantliffe, D. J.; Wheeler, R. M.; Manukian, A.; Heath, R. R.

    1996-01-01

    To investigate the effects of environment on plant volatile emissions, 'Waldmann's Green' leaf lettuce was cultivated under different levels of photosynthetic photon flux (PPF), photoperiod, and temperature. A modified growth chamber was used to sample plant volatile emissions nondestructively, over time, and under controlled conditions. Total volatile emission rates were significantly higher from lettuce cultivated under PPF of 360 or 200 micromoles m-2 s-1 compared to 105 micromoles m-2 s-1, and significantly higher under a 16-h photoperiod than an 8-h photoperiod. No differences were detected among emission rates from different temperature treatments. In controlled environments, emissions could be regulated by adjusting environmental conditions accordingly.

  5. The integrative effects of population density, photoperiod, temperature, and host plant on the induction of alate aphids in Schizaphis graminum.

    PubMed

    An, Chunju; Fei, Xiaodong; Chen, Wenfeng; Zhao, Zhangwu

    2012-04-01

    The wheat aphid Schizaphis graminum (Rondani) displays wing dimorphism with both winged and wingless adult morphs. The winged morph is an adaptive microevolutionary response to undesirable environmental conditions, including undesirable population density, photoperiod, temperature, and host plant. Here we studied the integrative effects of population density, photoperiod, temperature, and host plant on the induction of alate aphids in S. graminum. The present results show that these four factors all play roles in inducing alate aphids in S. graminum but population density is the most important under almost all circumstances. In importance, population density is followed by photoperiod, host plant, and temperature, in that order. These results indicate that ambient environmental factors are highly important to stimulation of alate aphids in S. graminum, especially when population density reaches 64 individuals per leaf. © 2012 Wiley Periodicals, Inc.

  6. A Mechanism for Frequency Modulation in Songbirds Shared with Humans

    PubMed Central

    Margoliash, Daniel

    2013-01-01

    In most animals that vocalize, control of fundamental frequency is a key element for effective communication. In humans, subglottal pressure controls vocal intensity but also influences fundamental frequency during phonation. Given the underlying similarities in the biomechanical mechanisms of vocalization in humans and songbirds, songbirds offer an attractive opportunity to study frequency modulation by pressure. Here, we present a novel technique for dynamic control of subsyringeal pressure in zebra finches. By regulating the opening of a custom-built fast valve connected to the air sac system, we achieved partial or total silencing of specific syllables, and could modify syllabic acoustics through more complex manipulations of air sac pressure. We also observed that more nuanced pressure variations over a limited interval during production of a syllable concomitantly affected the frequency of that syllable segment. These results can be explained in terms of a mathematical model for phonation that incorporates a nonlinear description for the vocal source capable of generating the observed frequency modulations induced by pressure variations. We conclude that the observed interaction between pressure and frequency was a feature of the source, not a result of feedback control. Our results indicate that, beyond regulating phonation or its absence, regulation of pressure is important for control of fundamental frequencies of vocalizations. Thus, although there are separate brainstem pathways for syringeal and respiratory control of song production, both can affect airflow and frequency. We hypothesize that the control of pressure and frequency is combined holistically at higher levels of the vocalization pathways. PMID:23825417

  7. A mechanism for frequency modulation in songbirds shared with humans.

    PubMed

    Amador, Ana; Margoliash, Daniel

    2013-07-03

    In most animals that vocalize, control of fundamental frequency is a key element for effective communication. In humans, subglottal pressure controls vocal intensity but also influences fundamental frequency during phonation. Given the underlying similarities in the biomechanical mechanisms of vocalization in humans and songbirds, songbirds offer an attractive opportunity to study frequency modulation by pressure. Here, we present a novel technique for dynamic control of subsyringeal pressure in zebra finches. By regulating the opening of a custom-built fast valve connected to the air sac system, we achieved partial or total silencing of specific syllables, and could modify syllabic acoustics through more complex manipulations of air sac pressure. We also observed that more nuanced pressure variations over a limited interval during production of a syllable concomitantly affected the frequency of that syllable segment. These results can be explained in terms of a mathematical model for phonation that incorporates a nonlinear description for the vocal source capable of generating the observed frequency modulations induced by pressure variations. We conclude that the observed interaction between pressure and frequency was a feature of the source, not a result of feedback control. Our results indicate that, beyond regulating phonation or its absence, regulation of pressure is important for control of fundamental frequencies of vocalizations. Thus, although there are separate brainstem pathways for syringeal and respiratory control of song production, both can affect airflow and frequency. We hypothesize that the control of pressure and frequency is combined holistically at higher levels of the vocalization pathways.

  8. Mechanisms underlying the social enhancement of vocal learning in songbirds

    PubMed Central

    Chen, Yining; Matheson, Laura E.; Sakata, Jon T.

    2016-01-01

    Social processes profoundly influence speech and language acquisition. Despite the importance of social influences, little is known about how social interactions modulate vocal learning. Like humans, songbirds learn their vocalizations during development, and they provide an excellent opportunity to reveal mechanisms of social influences on vocal learning. Using yoked experimental designs, we demonstrate that social interactions with adult tutors for as little as 1 d significantly enhanced vocal learning. Social influences on attention to song seemed central to the social enhancement of learning because socially tutored birds were more attentive to the tutor’s songs than passively tutored birds, and because variation in attentiveness and in the social modulation of attention significantly predicted variation in vocal learning. Attention to song was influenced by both the nature and amount of tutor song: Pupils paid more attention to songs that tutors directed at them and to tutors that produced fewer songs. Tutors altered their song structure when directing songs at pupils in a manner that resembled how humans alter their vocalizations when speaking to infants, that was distinct from how tutors changed their songs when singing to females, and that could influence attention and learning. Furthermore, social interactions that rapidly enhanced learning increased the activity of noradrenergic and dopaminergic midbrain neurons. These data highlight striking parallels between humans and songbirds in the social modulation of vocal learning and suggest that social influences on attention and midbrain circuitry could represent shared mechanisms underlying the social modulation of vocal learning. PMID:27247385

  9. Effects of landscape composition and configuration on migrating songbirds: inference from and individual-based model

    Treesearch

    Emily Cohen; Scott Pearson; Frank Moore

    2014-01-01

    The behavior of long-distance migrants during stopover is constrained by the need to quickly and safely replenish energetic reserves. Replenishing fuel stores at stopover sites requires adjusting to unfamiliar landscapes with little to no information about the distribution of resources. Despite their critical importance to the success of songbird migration, the effects...

  10. Social Modulation during Songbird Courtship Potentiates Midbrain Dopaminergic Neurons

    PubMed Central

    Huang, Ya-Chun; Hessler, Neal A.

    2008-01-01

    Synaptic transmission onto dopaminergic neurons of the mammalian ventral tegmental area (VTA) can be potentiated by acute or chronic exposure to addictive drugs. Because rewarding behavior, such as social affiliation, can activate the same neural circuitry as addictive drugs, we tested whether the intense social interaction of songbird courtship may also potentiate VTA synaptic function. We recorded glutamatergic synaptic currents from VTA of male zebra finches who had experienced distinct social and behavioral conditions during the previous hour. The level of synaptic transmission to VTA neurons, as assayed by the ratio of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) to N-methyl-D-aspartic acid (NMDA) glutamate receptor mediated synaptic currents, was increased after males sang to females, and also after they saw females without singing, but not after they sang while alone. Potentiation after female exposure alone did not appear to result from stress, as it was not blocked by inhibition of glucocorticoid receptors. This potentiation was restricted to synapses of dopaminergic projection neurons, and appeared to be expressed postsynaptically. This study supports a model in which VTA dopaminergic neurons are more strongly activated during singing used for courtship than during non-courtship singing, and thus can provide social context-dependent modulation to forebrain areas. More generally, these results demonstrate that an intense social encounter can trigger the same pathways of neuronal plasticity as addictive drugs. PMID:18827927

  11. Evaluation of a reproductive index for estimating songbird productivity: Case study of the golden-cheeked warbler

    Treesearch

    Jennifer L. Reidy; Lisa O' Donnell; Frank R. Thompson

    2015-01-01

    It is critically important to determine and understand relationships between endangered species populations and landscape and habitat features to effectively manage and conserve populations and the habitats they rely on. Several recent studies focused on the golden-cheeked warbler (Setophaga chrysoparia), an endangered songbird that breeds...

  12. Effects of spectral composition, photoperiod and light intensity on the gonadal development of Atlantic salmon Salmo salar in recirculating aquaculture systems (RAS)

    NASA Astrophysics Data System (ADS)

    Qiu, Denggao; Xu, Shihong; Song, Changbin; Chi, Liang; Li, Xian; Sun, Guoxiang; Liu, Baoliang; Liu, Ying

    2015-01-01

    Artificial lighting regimes have been successfully used to inhibit sexual maturity of Atlantic salmon in confinement. However, when these operations are applied in commercial recirculating aquaculture systems (RAS) using standard lighting technology, sexual maturation is not suppressed. In this study, an L9 (33) orthogonal design was used to determine the effects of three factors (spectral composition, photoperiod, and light intensity) on the gonadal development of Atlantic salmon in RAS. We demonstrated that the photoperiod at the tested levels had a much greater effect on the gonadosomatic index and female Fulton condition factor than spectral composition and light intensity. The photoperiod had a significant effect on the secretion of sex steroids and melatonin ( P<0.05), and a short photoperiod delayed sex steroid and melatonin level increases. The three test factors had no significant effects on the survival rate, specific growth rate, relative weight gain, and male Fulton condition factor ( P>0.05). The optimum lighting levels in female and male Atlantic salmon were LD 8:16, 455 nm (or 625 nm), 8.60 W/m2; and LD 8:16, 8.60 W/m2, 455 nm respectively. These conditions not only delayed gonadal development, but also had no negative effects on Atlantic salmon growth in RAS. These results demonstrate that a combination of spectral composition, photoperiod and light intensity is effective at delaying the gonadal development of both male and female salmon in RAS.

  13. Influence of Light Intensity and Photoperiod on the Seed Germination of Four Rhododendron Species in Taiwan.

    PubMed

    Lin, Lei-Chen; Wang, Chang-Sheng

    2017-01-01

    There are 15 native Rhododendron species in Taiwan, among which 11 species are endemic and compose 73% of these native species. Although researchers predominantly use cuttings to propagate Rhododendron shrubs, there are no studies on the seed germination of Rhododendron species. The objective of this study was to evaluate the seed germination of four Rhododendron species in Taiwan under different light intensities and photoperiods. Two experiments on the seed germination percentage of R. breviperulatum, R. kanehirai, R. ovatum and R. simsii were conducted in this study. The first experiment was to identify the seed germination percentage of these four Rhododendron species using different light intensities (0, 700, 1400 and 3200 lux). The second experiment was to clarify the seed germination percentage of these four Rhododendron species using different photoperiods (0, 1, 4 and 16 h). All statistical analyses were performed using Statistical Package for the Social Science (SPSS12.0) for Windows software program. The data were analyzed using Tukey's multiple range test at the p<0.05 significance level. After 30 days, no seed germination occurred in darkness. The highest average seed germination percentages were all observed at 700 lux: R. breviperulatum (83.3%), R. kanehirai (68.9%), R. ovatum (85.6%) and R. simsii (92.2%). The highest average germination percentages of seeds were observed in R. breviperulatum at 16 h (83.3%), R. kanehirai at 1 h (60.0%), R. ovatum at 16 h (84.4%) and R. simsii at 16 h (85.6%). According to the results, these four Rhododendron species required light for germination. There were significant differences (p<0.05) in the seed germination of these four Rhododendron species for light intensity greater than 700 lux. Similar results were observed with photoperiods. The seed germination percentage of R. breviperulatum, R. ovatum and R. simsii increased with increasing photoperiod.

  14. Evaluation of yield and quality of photoperiod sensitive sorghum and sorghum sudangrass

    USDA-ARS?s Scientific Manuscript database

    A 2-year study was conducted at 2 sites (Hancock, Marshfield) in central Wisconsin to assess yield and quality of photoperiod sensitive (PS) and non-PS sorghums in relation to corn planted on 2 dates and harvested once or twice. At each site, treatments were arranged as a split-split plot in a rando...

  15. Cloning of quantitative trait genes from rice reveals conservation and divergence of photoperiod flowering pathways in Arabidopsis and rice

    PubMed Central

    Matsubara, Kazuki; Hori, Kiyosumi; Ogiso-Tanaka, Eri; Yano, Masahiro

    2014-01-01

    Flowering time in rice (Oryza sativa L.) is determined primarily by daylength (photoperiod), and natural variation in flowering time is due to quantitative trait loci involved in photoperiodic flowering. To date, genetic analysis of natural variants in rice flowering time has resulted in the positional cloning of at least 12 quantitative trait genes (QTGs), including our recently cloned QTGs, Hd17, and Hd16. The QTGs have been assigned to specific photoperiodic flowering pathways. Among them, 9 have homologs in the Arabidopsis genome, whereas it was evident that there are differences in the pathways between rice and Arabidopsis, such that the rice Ghd7–Ehd1–Hd3a/RFT1 pathway modulated by Hd16 is not present in Arabidopsis. In this review, we describe QTGs underlying natural variation in rice flowering time. Additionally, we discuss the implications of the variation in adaptive divergence and its importance in rice breeding. PMID:24860584

  16. [Motility of rats exposed to an altered photoperiod in the open field test].

    PubMed

    Sopova, I Iu; Zamorskiĭ, I I

    2012-01-01

    Motility of rats exposed to an altered photoperiod has been studied in the open field test. It has been shown that physical activity of rats kept in darkness declined. The correlation parameters of locomotor activity as compared to previous data changed in animals kept in continuous light.

  17. Changes in growth conditions alter the male strobilus gene expression pattern in Cryptomeria japonica.

    PubMed

    Fukui, Mitsue

    2003-11-01

    Two-year old saplings grown from cuttings of Cryptomeria japonica D. Don initiate strobilus development following treatment with gibberellic acid under long-day photoperiods. At 25 degrees C with a 14-h photoperiod in a phytotron, male strobili initiated normally; however, they remained green and fell from the saplings prematurely. To examine the change in male strobilus development at the molecular level, three genes expressed specifically in male strobili were analyzed. Two were MADS box genes homologous to the B-function genes in angiosperms, CjMADS1 and CjMADS2, and the third was Cry j I, which encodes an allergen protein, and this gene is expressed mainly in microspores. Under phytotron growing conditions, the homeotic genes were expressed constantly, which reflected the extended early developmental stage of male strobili. On the other hand, Cry j I expression was detected after a long delay just before strobilus development ceased. These results indicate that the expression of the genes related to male reproductive development in C. japonica is regulated by a factor(s) that is sensitive to environmental signals.

  18. Edge and area effects on the occurrence of migrant forest songbirds

    USGS Publications Warehouse

    Parker, T.H.; Stansberry, B.M.; Becker, C.D.; Gipson, P.S.

    2005-01-01

    Concerns about forest fragmentation and its conservation implications have motivated numerous studies that investigate the influence of forest patch area and forest edge on songbird distribution patterns. The generalized effects of forest patch size and forest edge on animal distributions is still debatable because forest patch size and forest edge are often confounded and because of an incomplete synthesis of available data. To fill a portion of this gap, we incorporated all available published data (33 papers) in meta-analyses of forest edge and area effects on site occupancy patterns for 26 Neotropical migrant forest-nesting songbirds in eastern North America. All reported area effects are confounded or potentially confounded by edge effects, and we refer to these as "confounded" studies. The converse, however, is not true and most reported edge effects are independent of patch area. When considering only nonconfounded studies of edge effects, only 1 of 17 species showed significant edge avoidance and 3 had significant affinity for edges. In confounded studies, 12 of 22 species showed significant avoidance of small patches and edges, and 1 had an affinity for small patches and edges. Furthermore, average effect sizes averaged across studies or species tended to be higher for confounded studies than for edge studies. We discuss three possible reasons for differences in results between these two groups of studies. First, studies of edge effects tended to be carried out in landscapes with greater forest cover than studies of confounded effects; among confounded effects studies, as forest cover increased, we observed a nonsignificant trend towards decreasing strength of small patch or edge avoidance effects. Thus, the weaker effects in edge studies may be due to the fact that these studies were conducted in forest-dominated landscapes. Second, we may have detected strong effects only in confounded studies because area effects are much stronger than edge effects on

  19. Mechanisms and time course of vocal learning and consolidation in the adult songbird

    PubMed Central

    Tumer, Evren C.; Charlesworth, Jonathan D.; Brainard, Michael S.

    2011-01-01

    In songbirds, the basal ganglia outflow nucleus LMAN is a cortical analog that is required for several forms of song plasticity and learning. Moreover, in adults, inactivating LMAN can reverse the initial expression of learning driven via aversive reinforcement. In the present study, we investigated how LMAN contributes to both reinforcement-driven learning and a self-driven recovery process in adult Bengalese finches. We first drove changes in the fundamental frequency of targeted song syllables and compared the effects of inactivating LMAN with the effects of interfering with N-methyl-d-aspartate (NMDA) receptor-dependent transmission from LMAN to one of its principal targets, the song premotor nucleus RA. Inactivating LMAN and blocking NMDA receptors in RA caused indistinguishable reversions in the expression of learning, indicating that LMAN contributes to learning through NMDA receptor-mediated glutamatergic transmission to RA. We next assessed how LMAN's role evolves over time by maintaining learned changes to song while periodically inactivating LMAN. The expression of learning consolidated to become LMAN independent over multiple days, indicating that this form of consolidation is not completed over one night, as previously suggested, and instead may occur gradually during singing. Subsequent cessation of reinforcement was followed by a gradual self-driven recovery of original song structure, indicating that consolidation does not correspond with the lasting retention of changes to song. Finally, for self-driven recovery, as for reinforcement-driven learning, LMAN was required for the expression of initial, but not later, changes to song. Our results indicate that NMDA receptor-dependent transmission from LMAN to RA plays an essential role in the initial expression of two distinct forms of vocal learning and that this role gradually wanes over a multiday process of consolidation. The results support an emerging view that cortical-basal ganglia circuits can

  20. Cellular changes in the hamster testicular interstitium with ageing and after exposure to short photoperiod.

    PubMed

    Beltrán-Frutos, E; Seco-Rovira, V; Ferrer, C; Madrid, J F; Sáez, F J; Canteras, M; Pastor, L M

    2016-04-01

    The aim of this study was to evaluate the cellular changes that occur in the hamster testicular interstitium in two very different physiological situations involving testicular involution: ageing and exposure to a short photoperiod. The animals were divided into an 'age group' with three subgroups - young, adult and old animals - and a 'regressed group' with animals subjected to a short photoperiod. The testicular interstitium was characterised by light and electron microscopy. Interstitial cells were studied histochemically with regard to their proliferation, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP in situ nick end labelling (TUNEL+) and testosterone synthetic activity. We identified two types of Leydig cell: Type A cells showed a normal morphology, while Type B cells appeared necrotic. With ageing, pericyte proliferation decreased but there was no variation in the index of TUNEL-positive Leydig cells. In the regressed group, pericyte proliferation was greater and TUNEL-positive cells were not observed in the interstitium. The testicular interstitium suffered few ultrastructural changes during ageing and necrotic Leydig cells were observed. In contrast, an ultrastructural involution of Leydig cells with no necrosis was observed in the regressed group. In conclusion, the testicular interstitium of Mesocricetus auratus showed different cellular changes in the two groups (age and regressed), probably due to the irreversible nature of ageing and the reversible character of changes induced by short photoperiod.

  1. Synergistic effects of drought stress and photoperiods on phenology and secondary metabolism of Silybum marianum.

    PubMed

    Zahir, Adnan; Abbasi, Bilal Haider; Adil, Muhammad; Anjum, Sumaira; Zia, Muhammad; Ihsan-Ul-Haq

    2014-09-01

    Silybum marianum is an important medicinal plant of the family Asteraceae, well known for its set of bioactive isomeric mixture of secondary metabolites "silymarin", primarily acting as a hepato-protective agent. Abiotic stress augments plant secondary metabolism in different plant tissues to withstand harsh environmental fluctuations. In the current study, our aim was to induce drought stress in vitro on S. marianum under the influence of different photoperiod treatments to study the effects, with respect to variations in secondary metabolic profile and plant growth and development. S. marianum was extremely vulnerable to different levels of mannitol-induced drought stress. Water deficiency inhibited root induction completely and retarded plant growth was observed; however, phytochemical analysis revealed enhanced accumulation of total phenolic content (TPC), total flavonoid content (TFC), and total protein content along with several antioxidative enzymes. Secondary metabolic content was positively regulated with increasing degree of drought stress. A dependent correlation of seed germination frequency at mild drought stress and antioxidative activities was established with 2 weeks dark + 2 weeks 16/8 h photoperiod treatment, respectively, whereas a positive correlation existed for TPC and TFC when 4 weeks 16/8 h photoperiod treatment was applied. The effects of drought stress are discussed in relation to phenology, seed germination frequency, biomass build up, antioxidative potential, and secondary metabolites accumulation.

  2. Using Songbird Monitoring to Guide and Evaluate Riparian Restoration in Salmonid-Focused Stream Rehabilitation Projects

    Treesearch

    Ryan D. Burnett; Thomas Gardali; Geoffrey R. Geupel

    2005-01-01

    A restoration effort, primarily focused on reducing stranding and improving passage of anadromous fish, has been undertaken along sections of lower Clear Creek, Shasta County, California. Similar projects are occurring throughout California and, indeed, all of North America. To monitor the effects of these efforts at Clear Creek we implemented a multi-faceted songbird...

  3. Songbird nest survival is invariant to early-successional restoration treatments in a large river floodplain

    Treesearch

    Dirk E. Burhans; Brian G. Root; Terry L. Shaffer; Daniel C. Dey

    2010-01-01

    We monitored songbird nest survival in two reforesting, ∼50-ha former cropland sites along the Missouri River in central Missouri from 2001 to 2003. Sites were partitioned into three experimental units, each receiving one of three tree planting treatments. Nest densities varied among restoration treatments for four of five species, but overall nest survival...

  4. Songbird response to group selection harvests and clearcuts in a New Hampshire northern hardwood forest

    Treesearch

    Christine A. Costello; Mariko Yamasaki; Peter J. Pekins; William B. Leak; Christopher D. Neefus

    2000-01-01

    Clearcutting creates habitat for many species of early successional songbirds; however, little information is available on bird use of small forest openings created by group selection harvests. Group selection harvests are increasing on the White Mountain National Forest due to negative public response to clearcutting. The objective of this study was to determine if...

  5. Photoperiod induced obesity in the Brandt's vole (Lasiopodomys brandtii): a model of ‘healthy obesity’?

    PubMed Central

    Liu, Xin-Yu; Yang, Deng-Bao; Xu, Yan-Chao; Gronning, Marianne O. L.; Zhang, Fang; Wang, De-Hua; Speakman, John R.

    2016-01-01

    ABSTRACT Brandt's voles have an annual cycle of body weight and adiposity. These changes can be induced in the laboratory by manipulation of photoperiod. In the present study, male captive-bred Brandt's voles aged 35 days were acclimated to a short day (SD) photoperiod (8L:16D) for 70 days. A subgroup of individuals (n=16) were implanted with transmitters to monitor physical activity and body temperature. They were then randomly allocated into long day (LD=16L:8D) (n=19, 8 with transmitters) and SD (n=18, 8 with transmitters) groups for an additional 70 days. We monitored aspects of energy balance, glucose and insulin tolerance (GTT and ITT), body composition and organ fat content after exposure to the different photoperiods. LD voles increased in weight for 35 days and then re-established stability at a higher level. At the end of the experiment LD-exposed voles had greater white adipose tissue mass than SD voles (P=0.003). During weight gain they did not differ in their food intake or digestive efficiency; however, daily energy expenditure was significantly reduced in the LD compared with SD animals (ANCOVA, P<0.05) and there was a trend to reduced resting metabolic rate RMR (P=0.075). Physical activity levels were unchanged. Despite different levels of fat storage, the GTT and ITT responses of SD and LD voles were not significantly different, and these traits were not correlated to body fatness. Hence, the photoperiod-induced obesity was independent on disruptions to glucose homeostasis, indicating a potential adaptive decoupling of these states in evolutionary time. Fat content in both the liver and muscle showed no significant difference between LD and SD animals. How voles overcome the common negative aspects of fat storage might make them a useful model for understanding the phenomenon of ‘healthy obesity’. PMID:27736740

  6. The effect of photoperiod on tuberization in cultivated x wild potato species hybrids

    USDA-ARS?s Scientific Manuscript database

    Wild Solanum species offer a valuable source of genetic diversity for potato improvement. Most of these species are found in equatorial South and Central America and they do not tuberize under long day photoperiods typical of those in the major potato production areas of North America, Europe and As...

  7. Photoperiod and growing degree days effect on dry matter partitioning in Jerusalem artichoke

    USDA-ARS?s Scientific Manuscript database

    The effect of photoperiod and growing degree days (GDD) on dry matter and dry partitioning in Jerusalem artichoke was investigated during 2008-09 and 2009-10. Three Jerusalem artichoke genotypes (CN-52867, JA-89 and HEL-65) were planted in 15 day-intervals between with thirteen different dates (Sep...

  8. Influences of graded dose of melatonin on the levels of blood glucose and adrenal catecholamines in male roseringed parakeets (Psittacula krameri ) under different photoperiods.

    PubMed

    Maitra, S K; Dey, M; Dutta, S; Bhattacharya, S; Dey, R; Sengupta, A

    2000-12-01

    Effects of daily evening (just before the onset of darkness in a 24 h light dark cycle) administration of graded doses (25, 50, or 100 microg/100 g body wt./day for 30 days) of melatonin on the concentrations of blood glucose and adrenal catecholamines were studied in sexually active male roseringed parakeets under natural (NP; approximately 12L: 12D) and artificial long (LP; 16L: 8D) and short (SP; 8L: 16D) photoperiods. Blood samples and adrenal glands were collected from each bird during the mid-day on the following day of the last treatment. The concentrations of glucose in blood and epinephrine (E) and norepinephrine (NE) in the adrenals were measured. The results of the study indicated that exogenous melatonin induces hypo- or hyperglycemia depending on the dose of hormone administered as well as to the length of photoperiod to which birds were exposed. The levels of E and NE in the adrenals were shown also to vary in relation to photoperiod and the dose of melatonin administered. But the nature of the influence of melatonin becomes different under altered photoperiodic conditions. It appears that short photoperiods are more effective than long photoperiods as a modulator of glycemic and adrenal catecholaminergic responses to exogenous melatonin. A statistically significant correlation between the levels of blood glucose and that of E and NE in the adrenals was found in the control birds, but not in the melatonin treated birds. The results suggested that the responses of blood glucose and adrenal catecholamines to the treatment with melatonin in the roseringed parakeets may not be dependent on each other.

  9. Neural responses in songbird forebrain reflect learning rates, acquired salience, and stimulus novelty after auditory discrimination training.

    PubMed

    Bell, Brittany A; Phan, Mimi L; Vicario, David S

    2015-03-01

    How do social interactions form and modulate the neural representations of specific complex signals? This question can be addressed in the songbird auditory system. Like humans, songbirds learn to vocalize by imitating tutors heard during development. These learned vocalizations are important in reproductive and social interactions and in individual recognition. As a model for the social reinforcement of particular songs, male zebra finches were trained to peck for a food reward in response to one song stimulus (GO) and to withhold responding for another (NoGO). After performance reached criterion, single and multiunit neural responses to both trained and novel stimuli were obtained from multiple electrodes inserted bilaterally into two songbird auditory processing areas [caudomedial mesopallium (CMM) and caudomedial nidopallium (NCM)] of awake, restrained birds. Neurons in these areas undergo stimulus-specific adaptation to repeated song stimuli, and responses to familiar stimuli adapt more slowly than to novel stimuli. The results show that auditory responses differed in NCM and CMM for trained (GO and NoGO) stimuli vs. novel song stimuli. When subjects were grouped by the number of training days required to reach criterion, fast learners showed larger neural responses and faster stimulus-specific adaptation to all stimuli than slow learners in both areas. Furthermore, responses in NCM of fast learners were more strongly left-lateralized than in slow learners. Thus auditory responses in these sensory areas not only encode stimulus familiarity, but also reflect behavioral reinforcement in our paradigm, and can potentially be modulated by social interactions. Copyright © 2015 the American Physiological Society.

  10. Interacting effects of photoperiod and photosynthetic photon flux on net carbon assimilation and starch accumulation in potato leaves

    NASA Technical Reports Server (NTRS)

    Stutte, G. W.; Yorio, N. C.; Wheeler, R. M.

    1996-01-01

    The effect of photoperiod (PP) on net carbon assimilation rate (Anet) and starch accumulation in newly mature canopy leaves of 'Norland' potato (Solanum tuberosum L.) was determined under high (412 varies as mol m-2s-1) and low (263 varies as mol m-2s-1) photosynthetic photon flux (PPF) conditions. The Anet decreased from 13.9 to 11.6 and 9.3 micromoles m-2s-1, and leaf starch increased from 70 to 129 and 118 mg g-1 drymass (DM) as photoperiod (PP) was increased from 12/12 to 18/6, and 24/0, respectively. Longer PP had a greater effect with high PPF conditions than with low PPF treatments, with high PPF showing greater decline in Anet. Photoperiod did not affect either the CO2 compensation point (50 micromoles mol-1) or CO2 saturation point (1100-1200 micromoles mol-1) for Anet. These results show an apparent limit to the amount of starch that can be stored (approximately 15% DM) in potato leaves. An apparent feedback mechanism exists for regulating Anet under high PPF, high CO2, and long PP, but there was no correlation between Anet and starch concentration in individual leaves. This suggests that maximum Anet cannot be sustained with elevated CO2 conditions under long PP (> or = 12 hours) and high PPF conditions. If a physiological limit exists for the fixation and transport of carbon,then increasing photoperiod and light intensity under high CO2 conditions is not the most appropriate means to maximize the yield of potatoes.

  11. Low temperature limits photoperiod control of smolting in atlantic salmon through endocrine mechanisms

    USGS Publications Warehouse

    McCormick, S.D.; Moriyama, S.

    2000-01-01

    We have examined the interaction of photoperiod and temperature in regulating the parr-smolt transformation and its endocrine control. Atlantic salmon juveniles were reared at a constant temperature of 10??C or ambient temperature (2??C from January to April followed by seasonal increase) under simulated natural day length. At 10??C, an increase in day length [16 h of light and 8 h of darkness (LD 16:8)] in February accelerated increases in gill Na+K+-ATPase activity, whereas fish at ambient temperature did not respond to increased day length. Increases in gill Na+K+-ATPase activity under both photoperiods occurred later at ambient temperature than at 10??C. Plasma growth hormone (GH), insulin-like growth factor, and thyroxine increased within 7 days of increased day length at 10??C and remained elevated for 5-9 wk; the same photoperiod treatment at 2??C resulted in much smaller increases of shorter duration. Plasma cortisol increased transiently 3 and 5 wk after LD 16:8 at 10??C and ambient temperature, respectively. Plasma thyroxine was consistently higher at ambient temperature than at 10??C. Plasma triiodothyronine was initially higher at 10??C than at ambient temperature, and there was no response to LD 16:8 under either temperature regimen. There was a strong correlation between gill Na+K+-ATPase activity and plasma GH; correlations were weaker with other hormones. The results provide evidence that low temperature limits the physiological response to increased day length and that GH, insulin-like growth factor I, cortisol, and thyroid hormones mediate the environmental control of the parr-smolt transformation.

  12. Relative influence of male and female care in determining nestling mass in a migratory songbird

    Treesearch

    Kirk Stodola; Eric Linder; David A. Buehler; Kathlee Franzreb; Daniel Kim; Robert Cooper

    2010-01-01

    Biparental care is common in birds with the allocation of effort being highly variable between the sexes. In most songbird species, the female typically provides the most care in the breeding cycle with both parents providing care when provisioning young. Food provisioning should be directly related to offspring quality; however, the relative influence each parent has...

  13. A productivity model for parasitized, multibrooded songbirds

    USGS Publications Warehouse

    Powell, L.A.; Knutson, M.G.

    2006-01-01

    We present an enhancement of a simulation model to predict annual productivity for Wood Thrushes (Hylocichla mustelina) and American Redstarts (Setophaga ruticilla); the model includes effects of Brown-headed Cowbird (Molothrus ater) parasitism. We used species-specific data from the Driftless Area Ecoregion of Wisconsin, Minnesota, and Iowa to parameterize the model as a case study. The simulation model predicted annual productivity of 2.03 ?? 1.60 SD for Wood Thrushes and 1.56 ?? 1.31 SD for American Redstarts. Our sensitivity analysis showed that high parasitism lowered Wood Thrush annual productivity more than American Redstart productivity, even though parasitism affected individual nests of redstarts more severely. Annual productivity predictions are valuable for habitat managers, but productivity is not easily obtained from field studies. Our model provides a useful means of integrating complex life history parameters to predict productivity for songbirds that experience nest parasitism. ?? The Cooper Ornithological Society 2006.

  14. Effects of parents and Brown-headed Cowbirds (Molothrus ater) on nest predation risk for a songbird

    Treesearch

    Quresh S. Latif; Sacha K. Heath; John T. Rotenberry

    2012-01-01

    Nest predation limits avian fitness, so ornithologists study nest predation, but they often only document patterns of predation rates without substantively investigating underlying mechanisms. Parental behavior and predator ecology are two fundamental drivers of predation rates and patterns, but the role of parents is less certain, particularly for songbirds. Previous...

  15. Neuroendocrine mechanism of food intake and energy regulation in Japanese quail under differential simulated photoperiodic conditions: Involvement of hypothalamic neuropeptides, AMPK, insulin and adiponectin receptors.

    PubMed

    Banerjee, Somanshu; Chaturvedi, Chandra Mohini

    2018-05-26

    Neuroendocrine coordination between the reproductive and energy regulatory hypothalamic circuitries not only tightly regulates food intake and energy expenditure but also maintains the body weight and reproduction. The effect of different simulated photoperiodic conditions on food intake and neuroendocrine mechanism of energy homeostasis in Japanese quail is not investigated till date. Hence, our present study is designed to elucidate the effect of different simulated photoperiodic conditions on food consumption and neuroendocrine mechanism(s) of energy regulation in this poultry species. The alterations in hypothalamic energy balancing neuropeptides (NPY/AgRP/CART), polypeptide hormone precursor (POMC), protein kinase (AMPK-p-AMPK) as well as receptors of insulin and adiponectin [Insulin Receptor (IR), Adiponectin Receptor 1 & 2] have been investigated in photosensitive (PS), scotorefractory (SR),photorefractory (PR) and scotosensitive (SS) quail. Immunofluorescence and western blotting were used to quantify the expression of these peptides and proteins. Results showed increased food consumption and body weight gain, along with increased expression of NPY, AgRP, IR, adiponectin receptors and p-AMPK, decreased CART and POMC in the hypothalamus of photosensitive and scotorefractory quail. While, opposite findings were observed in photorefractory and scotosensitive quail. Hence, this study may suggest the hypothalamic energy channelization towards reproductive axis in photosensitive and scotorefractory quail to support the full breeding conditions, while hypothalamic energy deprivation in photorefractory and scotosensitive quail leads to reproductive quiescence. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Cortical inter-hemispheric circuits for multimodal vocal learning in songbirds.

    PubMed

    Paterson, Amy K; Bottjer, Sarah W

    2017-10-15

    Vocal learning in songbirds and humans is strongly influenced by social interactions based on sensory inputs from several modalities. Songbird vocal learning is mediated by cortico-basal ganglia circuits that include the SHELL region of lateral magnocellular nucleus of the anterior nidopallium (LMAN), but little is known concerning neural pathways that could integrate multimodal sensory information with SHELL circuitry. In addition, cortical pathways that mediate the precise coordination between hemispheres required for song production have been little studied. In order to identify candidate mechanisms for multimodal sensory integration and bilateral coordination for vocal learning in zebra finches, we investigated the anatomical organization of two regions that receive input from SHELL: the dorsal caudolateral nidopallium (dNCL SHELL ) and a region within the ventral arcopallium (Av). Anterograde and retrograde tracing experiments revealed a topographically organized inter-hemispheric circuit: SHELL and dNCL SHELL , as well as adjacent nidopallial areas, send axonal projections to ipsilateral Av; Av in turn projects to contralateral SHELL, dNCL SHELL , and regions of nidopallium adjacent to each. Av on each side also projects directly to contralateral Av. dNCL SHELL and Av each integrate inputs from ipsilateral SHELL with inputs from sensory regions in surrounding nidopallium, suggesting that they function to integrate multimodal sensory information with song-related responses within LMAN-SHELL during vocal learning. Av projections share this integrated information from the ipsilateral hemisphere with contralateral sensory and song-learning regions. Our results suggest that the inter-hemispheric pathway through Av may function to integrate multimodal sensory feedback with vocal-learning circuitry and coordinate bilateral vocal behavior. © 2017 Wiley Periodicals, Inc.

  17. Reward and vocal production: song-associated place preference in songbirds.

    PubMed

    Riters, Lauren V; Stevenson, Sharon A

    2012-05-15

    Vocal production is crucial for successful social interactions in multiple species. Reward can strongly influence behavior; however, the extent to which reward systems influence vocal behavior is unknown. In songbirds, singing occurs in different contexts. It can be spontaneous and undirected (e.g., song produced alone or as part of a large flock) or directed towards a conspecific (e.g., song used to attract a mate or influence a competitor). In this study, we developed a conditioned place preference paradigm to measure reward associated with different types of singing behavior in two songbird species. Both male zebra finches and European starlings developed a preference for a chamber associated with production of undirected song, suggesting that the production of undirected song is tightly coupled to intrinsic reward. In contrast, neither starlings nor zebra finches developed a place preference in association with directed song; however, male starlings singing directed song that failed to attract a female developed a place aversion. Unsuccessful contact calling behavior was also associated with a place aversion. These findings suggest that directed vocal behavior is not tightly linked to intrinsic reward but may be externally reinforced by social interactions. Data across two species thus support the hypothesis that the production of undirected but not directed song is tightly coupled to intrinsic reward. This study is the first to identify song-associated reward and suggests that reward associated with vocal production differs depending upon the context in which communication occurs. The findings have implications for understanding what motivates animals to engage in social behaviors and ways in which distinct reward mechanisms function to direct socially appropriate behaviors. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. The Vaccinium corymbosum FLOWERING LOCUS T-like gene (VcFT): a flowering activator reverses photoperiodic and chilling requirements in blueberry.

    PubMed

    Song, Guo-qing; Walworth, Aaron; Zhao, Dongyan; Jiang, Ning; Hancock, James F

    2013-11-01

    The blueberry FLOWERING LOCUS T ( FT )-like gene ( VcFT ) cloned from the cDNA of a tetraploid, northern highbush blueberry ( Vaccinium corymbosum L.) is able to reverse the photoperiodic and chilling requirements and drive early and continuous flowering. Blueberry is a woody perennial bush with a longer juvenile period than annual crops, requiring vernalization to flower normally. Few studies have been reported on the molecular mechanism of flowering in blueberry or other woody plants. Because FLOWERING LOCUS T (FT) from Arabidopsis thaliana plays a multifaceted role in generating mobile molecular signals to regulate plant flowering time, isolation and functional analysis of the blueberry (Vaccinium corymbosum L.) FT-like gene (VcFT) will facilitate the elucidation of molecular mechanisms of flowering in woody plants. Based on EST sequences, a 525-bpVcFT was identified and cloned from the cDNA of a tetraploid, northern highbush blueberry cultivar, Bluecrop. Ectopic expression of 35S:VcFT in tobacco induced flowering an average of 28 days earlier than wild-type plants. Expression of the 35S:VcFT in the blueberry cultivar Aurora resulted in an extremely early flowering phenotype, which flowered not only during in vitro culture, a growth stage when nontransgenic shoots had not yet flowered, but also in 6-10-week old, soil-grown transgenic plants, in contrast to the fact that at least 1 year and 800 chilling hours are required for the appearance of the first flower of both nontransgenic 'Aurora' and transgenic controls with the gusA. These results demonstrate that the VcFT is a functional floral activator and overexpression of the VcFT is able to reverse the photoperiodic and chilling requirements and drive early and continuous flowering.

  19. Influence of Old World bluestem (Bothrichloa ischaemum) monocultures on breeding density of three grassland songbirds in Oklahoma

    USGS Publications Warehouse

    George, Andrew D.; O'Connell, Timothy J.; Hickman, Karen R.; Leslie, David M.

    2009-01-01

    Despite persistent and widespread declines of grassland birds in North America, few studies have assessed differences between native grasslands and seeded monocultures as songbird habitat. In the Great Plains, many fields enrolled in the Conservation Reserve Program have been seeded to Old World bluestems (OWB), but there is evidence to suggest that OWB may not provide suitable conditions for several grassland bird species. Our objectives were to investigate the influence of OWB monocultures on vegetation structure, composition, and breeding densities of three common grassland bird species. In 2007, we used distance sampling to survey breeding songbirds in 6 native mixed grass prairie and 6 OWB fields in Garfield, Grant, and Alfalfa counties, Oklahoma. Native mixed grass prairie supported taller and denser vegetation, as well as greater forb cover than OWB fields. Breeding density of Grasshopper Sparrow (Ammodramus savannarum) was higher in OWB monocultures, while density of Dickcissel (Spiza americana) and Eastern Meadowlark (Sturnella magna) was similar among field types.

  20. Diapause response to photoperiod in an Arizona population of Lygus hesperus (Hemiptera: Miridae)

    USDA-ARS?s Scientific Manuscript database

    The western tarnished plant bug (Lygus hesperus Knight) is an important crop pest in the western U.S. that overwinters in an adult diapause. However, knowledge of L. hesperus diapause is incomplete. Eggs from field-collected adults were reared under photoperiods of 10:14, 11:13, 12:12, and 13:10 (L:...

  1. Possible role of songbirds and parakeets in transmission of influenza A(H7N9) virus to humans.

    PubMed

    Jones, Jeremy C; Sonnberg, Stephanie; Koçer, Zeynep A; Shanmuganatham, Karthik; Seiler, Patrick; Shu, Yuelong; Zhu, Huachen; Guan, Yi; Peiris, Malik; Webby, Richard J; Webster, Robert G

    2014-03-01

    Avian-origin influenza A(H7N9) recently emerged in China, causing severe human disease. Several subtype H7N9 isolates contain influenza genes previously identified in viruses from finch-like birds. Because wild and domestic songbirds interact with humans and poultry, we investigated the susceptibility and transmissibility of subtype H7N9 in these species. Finches, sparrows, and parakeets supported replication of a human subtype H7N9 isolate, shed high titers through the oropharyngeal route, and showed few disease signs. Virus was shed into water troughs, and several contact animals seroconverted, although they shed little virus. Our study demonstrates that a human isolate can replicate in and be shed by such songbirds and parakeets into their environment. This finding has implications for these birds' potential as intermediate hosts with the ability to facilitate transmission and dissemination of A(H7N9) virus.

  2. Possible Role of Songbirds and Parakeets in Transmission of Influenza A(H7N9) Virus to Humans

    PubMed Central

    Jones, Jeremy C.; Sonnberg, Stephanie; Koçer, Zeynep A.; Shanmuganatham, Karthik; Seiler, Patrick; Shu, Yuelong; Zhu, Huachen; Guan, Yi; Peiris, Malik; Webby, Richard J.

    2014-01-01

    Avian-origin influenza A(H7N9) recently emerged in China, causing severe human disease. Several subtype H7N9 isolates contain influenza genes previously identified in viruses from finch-like birds. Because wild and domestic songbirds interact with humans and poultry, we investigated the susceptibility and transmissibility of subtype H7N9 in these species. Finches, sparrows, and parakeets supported replication of a human subtype H7N9 isolate, shed high titers through the oropharyngeal route, and showed few disease signs. Virus was shed into water troughs, and several contact animals seroconverted, although they shed little virus. Our study demonstrates that a human isolate can replicate in and be shed by such songbirds and parakeets into their environment. This finding has implications for these birds’ potential as intermediate hosts with the ability to facilitate transmission and dissemination of A(H7N9) virus. PMID:24572739

  3. Expression and phylogenetic analyses reveal paralogous lineages of putatively classical and non-classical MHC-I genes in three sparrow species (Passer).

    PubMed

    Drews, Anna; Strandh, Maria; Råberg, Lars; Westerdahl, Helena

    2017-06-26

    The Major Histocompatibility Complex (MHC) plays a central role in immunity and has been given considerable attention by evolutionary ecologists due to its associations with fitness-related traits. Songbirds have unusually high numbers of MHC class I (MHC-I) genes, but it is not known whether all are expressed and equally important for immune function. Classical MHC-I genes are highly expressed, polymorphic and present peptides to T-cells whereas non-classical MHC-I genes have lower expression, are more monomorphic and do not present peptides to T-cells. To get a better understanding of the highly duplicated MHC genes in songbirds, we studied gene expression in a phylogenetic framework in three species of sparrows (house sparrow, tree sparrow and Spanish sparrow), using high-throughput sequencing. We hypothesize that sparrows could have classical and non-classical genes, as previously indicated though never tested using gene expression. The phylogenetic analyses reveal two distinct types of MHC-I alleles among the three sparrow species, one with high and one with low level of polymorphism, thus resembling classical and non-classical genes, respectively. All individuals had both types of alleles, but there was copy number variation both within and among the sparrow species. However, the number of highly polymorphic alleles that were expressed did not vary between species, suggesting that the structural genomic variation is counterbalanced by conserved gene expression. Overall, 50% of the MHC-I alleles were expressed in sparrows. Expression of the highly polymorphic alleles was very variable, whereas the alleles with low polymorphism had uniformly low expression. Interestingly, within an individual only one or two alleles from the polymorphic genes were highly expressed, indicating that only a single copy of these is highly expressed. Taken together, the phylogenetic reconstruction and the analyses of expression suggest that sparrows have both classical and non

  4. Conserved mechanisms of vocalization coding in mammalian and songbird auditory midbrain.

    PubMed

    Woolley, Sarah M N; Portfors, Christine V

    2013-11-01

    The ubiquity of social vocalizations among animals provides the opportunity to identify conserved mechanisms of auditory processing that subserve communication. Identifying auditory coding properties that are shared across vocal communicators will provide insight into how human auditory processing leads to speech perception. Here, we compare auditory response properties and neural coding of social vocalizations in auditory midbrain neurons of mammalian and avian vocal communicators. The auditory midbrain is a nexus of auditory processing because it receives and integrates information from multiple parallel pathways and provides the ascending auditory input to the thalamus. The auditory midbrain is also the first region in the ascending auditory system where neurons show complex tuning properties that are correlated with the acoustics of social vocalizations. Single unit studies in mice, bats and zebra finches reveal shared principles of auditory coding including tonotopy, excitatory and inhibitory interactions that shape responses to vocal signals, nonlinear response properties that are important for auditory coding of social vocalizations and modulation tuning. Additionally, single neuron responses in the mouse and songbird midbrain are reliable, selective for specific syllables, and rely on spike timing for neural discrimination of distinct vocalizations. We propose that future research on auditory coding of vocalizations in mouse and songbird midbrain neurons adopt similar experimental and analytical approaches so that conserved principles of vocalization coding may be distinguished from those that are specialized for each species. This article is part of a Special Issue entitled "Communication Sounds and the Brain: New Directions and Perspectives". Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Roosting behavior of a neotropical migrant songbird, the northern waterthrush Seiurus noveboracensis, during the non-breeding season

    Treesearch

    J.A.M. Smith; L.R. Reitsmas; L.I. Rockwood; P.P. and Marra

    2008-01-01

    Several species of Nearctic-Neotropical migratory songbirds appear to form roosting aggregations while on their wintering grounds but little is understood about the ecology of this behavior. We studied roosting behavior and patterns of roost habitat selection in the northern waterthrush Seiurus noveboracensis, during three winter years (2002

  6. Yield and nutritive value of photoperiod-sensitive sorghum and sorghum-sudangrass in central Wisconsin

    USDA-ARS?s Scientific Manuscript database

    A study was conducted to evaluate the yield and nutrient composition of photoperiod sensitive (PS) and non-PS forage sorghum, sorghum-sudangrass, and sudangrass compared to corn planted on 2 dates and harvested using single or multiple-cut harvest strategies at 2 research stations (Marshfield and Ha...

  7. QTL mapping for flowering-time and photoperiod insensitivity of wild cotton Gossypium darwinii Watt

    USDA-ARS?s Scientific Manuscript database

    Most wild and semi-wild species of the genus Gossypium are sensitive to photoperiodism. The wild germplasm cotton collection is a valuable source of genes for genetic improvement of current cotton cultivars. For the purpose of identifying quantitative trait loci (QTLs) controlling flowering, a bi-pa...

  8. The response of a Kansas winter bird community to weather, photoperiod, and year

    USGS Publications Warehouse

    Stapanian, M.A.; Smith, C.C.; Finck, E.J.

    1999-01-01

    We conducted a bird census along the same route nearly each week for 14 winters (194 censuses), and compared the mean number of species per station and the total number of species recorded on the census with the length of photoperiod and weather variables. We found significant differences among winters for both indicators of species richness. This result is consistent with previous studies in which abundance of food was measured in the same general area. Both indicators of species richness were negatively associated with the number of days after 1 November. This result is consistent with the hypothesis that wintering species dependent on nonrenewed food resources lose individuals to mortality or emigration. Further, there was a positive relationship between photoperiod and both indicators of species richness. This result is consistent with the hypothesis that the detection of individuals in the early morning hours increases with the amount of daylight they have available for foraging and social behaviors. Wind speed and temperature had negative and positive relationships, respectively, to species richness. The number of species per station was greatest on days when the ground was covered with dew and least on days when snow depth was more than 15 cm. When the 'winters' were divided into four 30-day 'quarters', most of the 61 species were recorded with equal frequency in each quarter. Eight species were detected less frequently at the end of winter than in the beginning. Four species exhibited the reverse pattern. Two species were recorded more frequently at the beginning and at the end of the winter than during the middle. Temperature, wind, photoperiod, successive winter day, year, and species-specific evolutionary history all affect winter bird species richness.

  9. The Songbird as a Percussionist: Syntactic Rules for Non-Vocal Sound and Song Production in Java Sparrows

    PubMed Central

    Soma, Masayo; Mori, Chihiro

    2015-01-01

    Music and dance are two remarkable human characteristics that are closely related. Communication through integrated vocal and motional signals is also common in the courtship displays of birds. The contribution of songbird studies to our understanding of vocal learning has already shed some light on the cognitive underpinnings of musical ability. Moreover, recent pioneering research has begun to show how animals can synchronize their behaviors with external stimuli, like metronome beats. However, few studies have applied such perspectives to unraveling how animals can integrate multimodal communicative signals that have natural functions. Additionally, studies have rarely asked how well these behaviors are learned. With this in mind, here we cast a spotlight on an unusual animal behavior: non-vocal sound production associated with singing in the Java sparrow (Lonchura oryzivora), a songbird. We show that male Java sparrows coordinate their bill-click sounds with the syntax of their song-note sequences, similar to percussionists. Analysis showed that they produced clicks frequently toward the beginning of songs and before/after specific song notes. We also show that bill-clicking patterns are similar between social fathers and their sons, suggesting that these behaviors might be learned from models or linked to learning-based vocalizations. Individuals untutored by conspecifics also exhibited stereotypical bill-clicking patterns in relation to song-note sequence, indicating that while the production of bill clicking itself is intrinsic, its syncopation appears to develop with songs. This paints an intriguing picture in which non-vocal sounds are integrated with vocal courtship signals in a songbird, a model that we expect will contribute to the further understanding of multimodal communication. PMID:25992841

  10. Effect of colostral volume, interval between calving and first milking, and photoperiod on colostral IgG concentrations in dairy cows.

    PubMed

    Morin, Dawn E; Nelson, Stephanie V; Reid, Eric D; Nagy, Dusty W; Dahl, Geoffrey E; Constable, Peter D

    2010-08-15

    To identify cow and management factors associated with colostral IgG concentration in dairy cows. Prospective observational study. 81 multiparous Holstein-Friesian cows from a single herd. Serum was obtained at the start of the nonlactating period, and cows were assigned to 1 of 4 photoperiod groups: natural day length (n = 22 cows), long days (16 h of light/d [21]) or short days (8 h of light/d [20]) for the entire nonlactating period, or natural day length followed by short days for the last 21 days of the nonlactating period (18). Serum and colostrum were collected at the first milking after calving. Regression analysis was used to investigate associations between colostral IgG concentration and the interval between calving and first milking, colostral volume, photoperiod, length of the nonlactating period, and season of calving. Colostral IgG concentration decreased by 3.7% during each subsequent hour after calving because of postparturient secretion by the mammary glands. The interval between calving and first milking and the colostral volume were significantly and negatively associated with colostral IgG concentration, with the former effect predominating. Photoperiod had no effect on colostral IgG concentration or volume. Serum protein concentration at calving correlated poorly with colostral IgG concentration. Dairy producers should harvest colostrum as soon as possible after calving to optimize transfer of passive immunity in neonatal calves. Photoperiod can be manipulated without adversely affecting colostral IgG concentration.

  11. Learning speed is affected by personality and reproductive investment in a songbird

    PubMed Central

    Martens, Tine; Pinxten, Rianne; Eens, Marcel

    2017-01-01

    Individuals from different taxa, including songbirds, differ consistently in behaviour and personality when facing different situations. Although our understanding of animal behaviour has increased, knowledge about between-individual differences in cognitive abilities is still limited. By using an experimental approach and a free-living songbird (Parus major) as a model, we attempted to understand between-individual differences in habituation to playbacks (as a proxy of learning speed), by investigating the role of personality, age and reproductive investment (clutch size). Pre-breeding males were tested for exploration (a proxy of personality) in standardized conditions. In addition, the same individuals were exposed to three playbacks in the field during incubation. Birds significantly moved less, stayed further away and overlapped less the playback with successive playback stimulation. While a decrease in the locomotor behaviour can be explained by personality, differences in habituation of overlapping were predicted by both reproductive investment and personality. Fast explorers habituated less. Moreover, males paired to females with larger clutches did not vary the intensity of overlapping. Since habituation requires information for recognition of non-threatening signals, personality may bias information gathering. While fast explorers may collect less information from the environment, slow explorers (reactive birds) seem to pay attention to environmental clues and collect detailed information. We provided evidence that the rate of habituation of behavioural responses, a proxy of cognitive abilities, may be affected by different factors and in a complex way. PMID:29020028

  12. Learning speed is affected by personality and reproductive investment in a songbird.

    PubMed

    Rivera-Gutierrez, Hector Fabio; Martens, Tine; Pinxten, Rianne; Eens, Marcel

    2017-01-01

    Individuals from different taxa, including songbirds, differ consistently in behaviour and personality when facing different situations. Although our understanding of animal behaviour has increased, knowledge about between-individual differences in cognitive abilities is still limited. By using an experimental approach and a free-living songbird (Parus major) as a model, we attempted to understand between-individual differences in habituation to playbacks (as a proxy of learning speed), by investigating the role of personality, age and reproductive investment (clutch size). Pre-breeding males were tested for exploration (a proxy of personality) in standardized conditions. In addition, the same individuals were exposed to three playbacks in the field during incubation. Birds significantly moved less, stayed further away and overlapped less the playback with successive playback stimulation. While a decrease in the locomotor behaviour can be explained by personality, differences in habituation of overlapping were predicted by both reproductive investment and personality. Fast explorers habituated less. Moreover, males paired to females with larger clutches did not vary the intensity of overlapping. Since habituation requires information for recognition of non-threatening signals, personality may bias information gathering. While fast explorers may collect less information from the environment, slow explorers (reactive birds) seem to pay attention to environmental clues and collect detailed information. We provided evidence that the rate of habituation of behavioural responses, a proxy of cognitive abilities, may be affected by different factors and in a complex way.

  13. Nocturnal migratory songbirds adjust their travelling direction aloft: evidence from a radiotelemetry and radar study

    PubMed Central

    Sjöberg, Sissel; Nilsson, Cecilia

    2015-01-01

    In order to fully understand the orientation behaviour of migrating birds, it is important to understand when birds set their travel direction. Departure directions of migratory passerines leaving stopover sites are often assumed to reflect the birds' intended travel directions, but this assumption has not been critically tested. We used data from an automated radiotelemetry system and a tracking radar at Falsterbo peninsula, Sweden, to compare the initial orientation of departing songbirds (recorded by radiotelemetry) with the orientation of songbird migrants in climbing and level flight (recorded by radar). We found that the track directions of birds at high altitudes and in level flight were more concentrated than the directions of departing birds and birds in climbing flight, which indicates that the birds adjust their travelling direction once aloft. This was further supported by a wide scatter of vanishing bearings in a subsample of radio-tracked birds that later passed an offshore radio receiver station 50 km southeast of Falsterbo. Track directions seemed to be more affected by winds in climbing compared with level flights, which may be explained by birds not starting to partially compensate for wind drift until they have reached cruising altitudes. PMID:26085501

  14. Night-time neuronal activation of Cluster N in a day- and night-migrating songbird.

    PubMed

    Zapka, Manuela; Heyers, Dominik; Liedvogel, Miriam; Jarvis, Erich D; Mouritsen, Henrik

    2010-08-01

    Magnetic compass orientation in a night-migratory songbird requires that Cluster N, a cluster of forebrain regions, is functional. Cluster N, which receives input from the eyes via the thalamofugal pathway, shows high neuronal activity in night-migrants performing magnetic compass-guided behaviour at night, whereas no activation is observed during the day, and covering up the birds' eyes strongly reduces neuronal activation. These findings suggest that Cluster N processes light-dependent magnetic compass information in night-migrating songbirds. The aim of this study was to test if Cluster N is active during daytime migration. We used behavioural molecular mapping based on ZENK activation to investigate if Cluster N is active in the meadow pipit (Anthus pratensis), a day- and night-migratory species. We found that Cluster N of meadow pipits shows high neuronal activity under dim-light at night, but not under full room-light conditions during the day. These data suggest that, in day- and night-migratory meadow pipits, the light-dependent magnetic compass, which requires an active Cluster N, may only be used during night-time, whereas another magnetosensory mechanism and/or other reference system(s), like the sun or polarized light, may be used as primary orientation cues during the day.

  15. Eavesdropping on the Arctic: Automated Bioacoustics Promise to Untangle Climate-Induced Shifts in Songbird Migration

    NASA Astrophysics Data System (ADS)

    Oliver, R.; Ellis, D.; Gough, L.; Chmura, H.; Sweet, S. K.; Boelman, N.; Krause, J.; Perez, J.; Wingfield, J.

    2017-12-01

    Climate change is altering the seasonality of environmental conditions and the phenology of vegetation, particularly at high northern latitudes. Yet changes in the phenology of wildlife that rely on northern ecosystems is significantly understudied. In much the same way that remote sensing enables global-scale observations of climate and vegetation, ground-based bioacoustic recording networks have the potential to vastly expand the spatial and temporal coverage of wildlife monitoring. However, the enormous datasets that autonomous recorders typically generate demand automated analyses that remain largely undeveloped. To unleash the potential for global-scale bioacoustic monitoring, we developed automated signal processing and machine learning algorithms to generate seasonal times series of breeding songbird vocal activity from 1200 hours of landscape-level recordings in northern Alaska. The calendar dates on which songbird communities arrived to their breeding grounds in five springs (2010-2014) were automatically extracted from the time series, and agreed within 3 days to those determined via traditional avian surveys (RMSE = 1.88 - 3.02). Relative to other years, our bioacoustic approach identified a 1-9 day delay in the arrival of long distance migratory songbird communities to their breeding grounds in 2013 - a spring characterized by persistent snow cover and cold temperatures. Differences in arrival timing among sites were strongly related to the date on which the landscape surrounding the microphone became snow-free, particularly in the supervised approach (supervised: R2 = 0.59, p < 0.01 and unsupervised: R2 = 0.13, p = 0.15). We found daily variation in vocal activity was heavily influenced by environmental conditions - primarily snow cover and temperature, and especially prior to egg laying (R2 = 0.61 +/- 0.07 vs. 0.23 +/- 0.07, p < 0.1) - suggesting that extending bioacoustics analysis beyond arrival date estimation requires coupling recordings with

  16. Comment on "No evidence of displacement due to wind turbines in breeding grassland songbirds"

    USGS Publications Warehouse

    Johnson, Douglas H.

    2016-01-01

    A recent article published in The Condor: Ornithological Applications by Hale et al. (2014) is entitled, “No evidence of displacement due to wind turbines in breeding grassland songbirds.” The conclusion stated in that title, unfortunately, is based on inappropriate statistical analysis of data collected by the authors. In fact, their data provide evidence of potential displacement by wind turbines in 2 of the 3 species considered.

  17. Abscisic Acid and the Photoperiodic Induction of Dormancy in Salix viminalis L.

    PubMed

    Alvim, R; Saunders, P F; Barros, R S

    1979-04-01

    A series of growth room experiments was carried out aiming to establish the role of abscisic acid on dormancy of Salix viminalis L. The inhibitor content and abscisic acid levels of extracts from roots, sap, leaves, and apical tissues of willow were measured using biological assay and gas-liquid chromatography.No evidence was obtained that photoperiodically mediated dormancy is associated with changes in abscisic acid levels or beta-inhibitor activity.

  18. Detection of Lyme disease spirochete, Borrelia burgdorferi sensu lato, including three novel genotypes in ticks (Acari: Ixodidae) collected from songbirds (Passeriformes) across Canada.

    PubMed

    Scott, John D; Lee, Min-Kuang; Fernando, Keerthi; Durden, Lance A; Jorgensen, Danielle R; Mak, Sunny; Morshed, Muhammad G

    2010-06-01

    Lyme disease is reported across Canada, but pinpointing the source of infection has been problematic. In this three-year, bird-tick-pathogen study (2004-2006), 366 ticks representing 12 species were collected from 151 songbirds (31 passerine species/subspecies) at 16 locations Canada-wide. Of the 167 ticks/pools tested, 19 (11.4%) were infected with Borrelia burgdorferi sensu lato (s.l.). Sequencing of the rrf-rrl intergenic spacer gene revealed four Borrelia genotypes: B. burgdorferi sensu stricto (s.s.) and three novel genotypes (BC genotype 1, BC genotype 2, BC genotype 3). All four genotypes were detected in spirochete-infected Ixodes auritulus (females, nymphs, larvae) suggesting this tick species is a vector for B. burgdorferi s.l. We provide first-time records for: ticks in the Yukon (north of 60 degrees latitude), northernmost collection of Amblyomma americanum in North America, and Amblyomma imitator in Canada. First reports of bird-derived ticks infected with B. burgdorferi s.l. include: live culture of spirochetes from Ixodes pacificus (nymph) plus detection in I. auritulus nymphs, Ixodes scapularis in New Brunswick, and an I. scapularis larva in Canada. We provide the first account of B. burgdorferi s. l. in an Ixodes muris tick collected from a songbird anywhere. Congruent with previous data for the American Robin, we suggest that the Common Yellowthroat, Golden-crowned Sparrow, Song Sparrow, and Swainson's Thrush are reservoir-competent hosts. Song Sparrows, the predominant hosts, were parasitized by I. auritulus harboring all four Borrelia genotypes. Our results show that songbirds import B. burgdorferi s.l.-infected ticks into Canada. Bird-feeding I. scapularis subadults were infected with Lyme spirochetes during both spring and fall migration in eastern Canada. Because songbirds disperse millions of infected ticks across Canada, people and domestic animals contract Lyme disease outside of the known and expected range.

  19. Expression and regulation of Icer mRNA in the Syrian hamster pineal gland.

    PubMed

    Diaz, Elena; Garidou, Marie-Laure; Dardente, Hugues; Salingre, Anthony; Pévet, Paul; Simonneaux, Valérie

    2003-04-10

    Inducible-cAMP early repressor (ICER) is a potent inhibitor of CRE (cAMP-related element)-driven gene transcription. In the rat pineal gland, it has been proposed to be part of the mechanisms involved in the shutting down of the transcription of the gene coding for arylalkylamine N-acetyltransferase (AA-NAT, the melatonin rhythm-generating enzyme). In this study, we report that ICER is expressed in the pineal gland of the photoperiodic rodent Syrian hamster although with some difference compared to the rat. In the Syrian hamster pineal, Icer mRNA levels, low at daytime, displayed a 20-fold increase during the night. Nighttime administration of a beta-adrenergic antagonist, propranolol, significantly reduced Icer mRNA levels although daytime administration of a beta-adrenergic agonist, isoproterenol, was unable to raise the low amount of Icer mRNA. These observations indicate that Icer mRNA expression is induced by the clock-driven norepinephrine release and further suggest that this stimulation is restricted to nighttime, as already observed for Aa-nat gene transcription. Furthermore, we found that the daily profile of Icer mRNA displayed photoperiodic variation with a lengthening of the nocturnal peak in short versus long photoperiod. These data indicate that ICER may be involved in both daily and seasonal regulation of melatonin synthesis in the Syrian hamster.

  20. Zebrafish take their cue from temperature but not photoperiod for the seasonal plasticity of thermal performance.

    PubMed

    Condon, Catriona H; Chenoweth, Stephen F; Wilson, Robbie S

    2010-11-01

    Organisms adjust to seasonal variability in the environment by responding to cues that indicate environmental change. As most studies of seasonal phenotypic plasticity test only the effect of a single environmental cue, how animals may integrate information from multiple cues to fine-tune plastic responses remains largely unknown. We examined the interaction between correlated (seasonally matching) and conflicting (seasonally opposite) temperature and photoperiod cues on the acclimation of performance traits in male zebrafish, Danio rerio. We acclimated fish for 8 weeks and then tested the change in thermal dependence of maximum burst swimming and feeding rate between 8 and 38°C. We predicted that correlated environmental cues should induce a greater acclimation response than uncorrelated cues. However, we found that only temperature was important for the seasonal acclimation of performance traits in zebrafish. Thermal acclimation shifted the thermal performance curve of both traits. For maximum burst swimming, performance increased for each group near the acclimation temperature and reduced in environments that were far from their acclimation temperature. The feeding rate of cold-acclimated zebrafish was reduced across the test temperature range compared with that of warm-acclimated fish. Our study is the first that has found no effect of the covariation between temperature and photoperiod acclimation cues on locomotor performance in fishes. Our results support the intuitive idea that photoperiod may be a less important seasonal cue for animals living at lower latitudes.

  1. Photoperiod-H1 (Ppd-H1) Controls Leaf Size1[OPEN

    PubMed Central

    Digel, Benedikt; Tavakol, Elahe; Verderio, Gabriele; Xu, Xin

    2016-01-01

    Leaf size is a major determinant of plant photosynthetic activity and biomass; however, it is poorly understood how leaf size is genetically controlled in cereal crop plants like barley (Hordeum vulgare). We conducted a genome-wide association scan for flowering time, leaf width, and leaf length in a diverse panel of European winter cultivars grown in the field and genotyped with a single-nucleotide polymorphism array. The genome-wide association scan identified PHOTOPERIOD-H1 (Ppd-H1) as a candidate gene underlying the major quantitative trait loci for flowering time and leaf size in the barley population. Microscopic phenotyping of three independent introgression lines confirmed the effect of Ppd-H1 on leaf size. Differences in the duration of leaf growth and consequent variation in leaf cell number were responsible for the leaf size differences between the Ppd-H1 variants. The Ppd-H1-dependent induction of the BARLEY MADS BOX genes BM3 and BM8 in the leaf correlated with reductions in leaf size and leaf number. Our results indicate that leaf size is controlled by the Ppd-H1- and photoperiod-dependent progression of plant development. The coordination of leaf growth with flowering may be part of a reproductive strategy to optimize resource allocation to the developing inflorescences and seeds. PMID:27457126

  2. WDR1 Presence in the Songbird Basilar Papilla

    PubMed Central

    Adler, Henry J.; Sanovich, Elena; Brittan-Powell, Elizabeth F.; Yan, Kai; Dooling, Robert J.

    2009-01-01

    WD40 repeat 1 protein (WDR1) was first reported in the acoustically injured chicken inner ear, and bioinformatics revealed that WDR1 has numerous WD40 repeats, important for protein-protein interactions. It has significant homology to actin interacting protein 1 (Aip1) in several lower species such as yeast, roundworm, fruitfly and frog. Several studies have shown that Aip1 binds cofilin/actin depolymerizing factor, and that these interactions are pivotal for actin disassembly via actin filament severing and actin monomer capping. However, the role of WDR1 in auditory function has yet to be determined. WDR1 is typically restricted to hair cells of the normal avian basilar papilla, but is redistributed towards supporting cells after acoustic overstimulation, suggesting that WDR1 may be involved in inner ear response to noise stress. One aim of the present study was to resolve the question as to whether stress factors, other than intense sound, could induce changes in WDR1 presence in the affected avian inner ear. Several techniques were used to assess WDR1 presence in the inner ears of songbird strains, including Belgian Waterslager (BW) canary, an avian strain with degenerative hearing loss thought to have a genetic basis. Reverse transcription, followed by polymerase chain reactions with WDR1-specific primers, confirmed WDR1 presence in the basilar papillae of adult BW, non-BW canaries, and zebra finches. Confocal microscopy examinations, following immunocytochemistry with anti-WDR1 antibody, localized WDR1 to the hair cell cytoplasm along the avian sensory epithelium. In addition, little, if any, staining by anti-WDR1 antibody was observed among supporting cells in the chicken or songbird ear. The present observations confirm and extend the early findings of WDR1 localization in hair cells, but not in supporting cells, in the normal avian basilar papilla. However, unlike supporting cells in the acoustically damaged chicken basilar papilla, the inner ear of the BW

  3. Photoperiod cues and patterns of genetic variation limit phenological responses to climate change in warm parts of species' range: Modeling diameter-growth cessation in coast Douglas-fir.

    PubMed

    Ford, Kevin R; Harrington, Constance A; St Clair, J Bradley

    2017-08-01

    The phenology of diameter-growth cessation in trees will likely play a key role in mediating species and ecosystem responses to climate change. A common expectation is that warming will delay cessation, but the environmental and genetic influences on this process are poorly understood. We modeled the effects of temperature, photoperiod, and seed-source climate on diameter-growth-cessation timing in coast Douglas-fir (an ecologically and economically vital tree) using high-frequency growth measurements across broad environmental gradients for a range of genotypes from different seed sources. Our model suggests that cool temperatures or short photoperiods can induce cessation in autumn. At cool locations (high latitude and elevation), cessation seems to be induced primarily by low temperatures in early autumn (under relatively long photoperiods), so warming will likely delay cessation and extend the growing season. But at warm locations (low latitude or elevation), cessation seems to be induced primarily by short photoperiods later in autumn, so warming will likely lead to only slight extensions of the growing season, reflecting photoperiod limitations on phenological shifts. Trees from seed sources experiencing frequent frosts in autumn or early winter tended to cease growth earlier in the autumn, potentially as an adaptation to avoid frost. Thus, gene flow into populations in warm locations with little frost will likely have limited potential to delay mean cessation dates because these populations already cease growth relatively late. In addition, data from an abnormal heat wave suggested that very high temperatures during long photoperiods in early summer might also induce cessation. Climate change could make these conditions more common in warm locations, leading to much earlier cessation. Thus, photoperiod cues, patterns of genetic variation, and summer heat waves could limit the capacity of coast Douglas-fir to extend its growing season in response to climate

  4. Testosterone treatment diminishes sickness behavior in male songbirds.

    PubMed

    Ashley, Noah T; Hays, Quentin R; Bentley, George E; Wingfield, John C

    2009-06-01

    Males of many vertebrate species are typically more prone to disease and infection than female conspecifics, and this sexual difference is partially influenced by the immunosuppressive properties of testosterone (T) in males. T-induced immunosuppression has traditionally been viewed as a pleiotropic handicap, rather than an adaptation. Recently, it has been hypothesized that suppression of sickness behavior, or the symptoms of infection, may have adaptive value if sickness interferes with the expression of T-mediated behaviors important for male reproductive success. We conduct a classic hormone replacement experiment to examine if T suppresses sickness behavior in a seasonally-breeding songbird, Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii). Triggered experimentally by bacterial lipopolysaccharide (LPS), sickness behavior includes decreased activity, anorexia, and weight loss. Gonadectomized (GDX) males that were treated with silastic implants filled with T exhibited suppression of behavioral and physiological responses to LPS compared to GDX and sham-GDX controls given empty implants. Sickness responses of control groups were statistically indistinguishable. T-implanted birds had significantly higher plasma T than control groups and levels were within the range associated with aggressive interactions during male-to-male contests. These findings imply that suppression of sickness behavior could occur when T is elevated to socially-modulated levels. Alternatively, it is possible that this suppressive effect is mediated through a stress-induced mechanism, as corticosterone levels were elevated in T-implanted subjects compared to controls. We propose that males wounded and infected during contests may gain a brief selective advantage by suppressing sickness responses that would otherwise impair competitive performance. The cost of immunosuppression would be manifested in males through an increased susceptibility to disease, which is presumably

  5. Effects of photoperiod regimes and ultraviolet-C radiations on biosynthesis of industrially important lignans and neolignans in cell cultures of Linum usitatissimum L. (Flax).

    PubMed

    Anjum, Sumaira; Abbasi, Bilal Haider; Doussot, Joël; Favre-Réguillon, Alain; Hano, Christophe

    2017-02-01

    Lignans and neolignans are principal bioactive components of Linum usitatissimum L. (Flax), having multiple pharmacological activities. In present study, we are reporting an authoritative abiotic elicitation strategy of photoperiod regimes along with UV-C radiations. Cell cultures were grown in different photoperiod regimes (24h-dark, 24h-light and 16L/8D h photoperiod) either alone or in combination with various doses (1.8-10.8kJ/m 2 ) of ultraviolet-C (UV-C) radiations. Secoisolariciresinol diglucoside (SDG), lariciresinol diglucoside (LDG), dehydrodiconiferyl alcohol glucoside (DCG), and guaiacylglycerol-β-coniferyl alcohol ether glucoside (GGCG) were quantified by using reverse phase-high performance liquid chromatography (RP-HPLC). Results showed that the cultures exposed to UV-C radiations, accumulated higher levels of lignans, neolignans and other biochemical markers than cultures grown under different photoperiod regimes. 3.6kJ/m 2 dose of UV-C radiations resulted in 1.86-fold (7.1mg/g DW) increase in accumulation of SDG, 2.25-fold (21.6mg/g DW) in LDG, and 1.33-fold (9.2mg/g DW) in GGCG in cell cultures grown under UV+photoperiod than their respective controls. Furthermore, cell cultures grown under UV+dark showed 1.36-fold (60.0mg/g DW) increase in accumulation of DCG in response to 1.8kJ/m 2 dose of UV-C radiations. Smilar trends were observed in productivity of SDG, LDG and GGCG. Additionally, 3.6kJ/m 2 dose of UV-C radiations also resulted in 2.82-fold (195.65mg/l) increase in total phenolic production, 2.94-fold (98.9mg/l) in total flavonoid production and 1.04-fold (95%) in antioxidant activity of cell cultures grown under UV+photoperiod. These findings open new dimensions for feasible production of biologically active lignans and neolignans by Flax cell cultures. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Riparian Songbird Abundance a Decade after Cattle Removal on Hart Mountain and Sheldon National Wildlife Refuges

    Treesearch

    Susan L. Earnst; Jennifer A. Ballard; David S. Dobkin

    2005-01-01

    Cattle were removed from the high desert riparian habitats of Hart Mountain and Sheldon National Wildlife Refuges in 1990. This study compares songbird abundance in 2000-2001 to that in 1991-1993 on 69 permanent plots. Of the 51 species for which detections were sufficient to calculate changes in abundance, 71 percent (36/51) exhibited a positive trend and 76 percent (...

  7. A winter distribution model for Bicknell's Thrush (Catharus bicknelli), a conservation tool for a threatened migratory songbird

    Treesearch

    K. P. McFarland; C. C. Rimmer; J. E. Goetz; Y. Aubry; J. M. Wunderle Jr.; A. Hayes-Sutton; J. M. Townsend; A. Llanes Sosa; A. Kirkconnell

    2013-01-01

    Conservation planning and implementation require identifying pertinent habitats and locations where protection and management may improve viability of targeted species. The winter range of Bicknell’s Thrush (Catharus bicknelli), a threatened Nearctic-Neotropical migratory songbird, is restricted to the Greater Antilles. We analyzed winter records from the mid-1970s to...

  8. Body temperature changes during simulated bacterial infection in a songbird: fever at night and hypothermia during the day.

    PubMed

    Sköld-Chiriac, Sandra; Nord, Andreas; Tobler, Michael; Nilsson, Jan-Åke; Hasselquist, Dennis

    2015-09-01

    Although fever (a closely regulated increase in body temperature in response to infection) typically is beneficial, it is energetically costly and may induce detrimentally high body temperatures. This can increase the susceptibility to energetic bottlenecks and risks of overheating in some organisms. Accordingly, it could be particularly interesting to study fever in small birds, which have comparatively high metabolic rates and high, variable body temperatures. We therefore investigated two aspects of fever and other sickness behaviours (circadian variation, dose dependence) in a small songbird, the zebra finch. We injected lipopolysaccharide (LPS) at the beginning of either the day or the night, and subsequently monitored body temperature, body mass change and food intake for the duration of the response. We found pronounced circadian variation in the body temperature response to LPS injection, manifested by (dose-dependent) hypothermia during the day but fever at night. This resulted in body temperature during the peak response being relatively similar during the day and night. Day-to-night differences might be explained in the context of circadian variation in body temperature: songbirds have a high daytime body temperature that is augmented by substantial heat production peaks during activity. This might require a trade-off between the benefit of fever and the risk of overheating. In contrast, at night, when body temperature is typically lower and less variable, fever can be used to mitigate infection. We suggest that the change in body temperature during infection in small songbirds is context dependent and regulated to promote survival according to individual demands at the time of infection. © 2015. Published by The Company of Biologists Ltd.

  9. Response to nestling throat ligatures by three songbirds

    USGS Publications Warehouse

    Robinson, G.L.; Conway, C.J.; Kirkpatrick, C.; Laroche, D.D.

    2010-01-01

    We attempted to collect diet samples using throat ligatures from nestlings of three songbird species in a riparian woodland in southeastern Arizona from May to August 2009. We had success with Song Sparrows (Melospiza melodia), observed adult Yellow-breasted Chats (Icteria virens) reclaim food from nestlings, and discontinued the use of throat ligatures when we observed an adult Abert's Towhee (Pipilo aberti) remove two, 34-day-old ligatured nestlings from its nest. Previous studies have reported problems (e.g., aggression toward nestlings by adults) with throat ligatures, but we are the first to document removal (and subsequent nestling mortality) in response to this technique. We urge investigators to exercise caution when using throat ligatures on species for which evidence of the safety and efficacy of this method are lacking, especially when nestlings are small in size relative to adults. ?? 2010 by the Wilson Ornithological Society.

  10. PHOTOPERIOD RESPONSE 1 (PHOR1)-like genes regulate shoot/root growth, starch accumulation, and wood formation in Populus.

    PubMed

    Zawaski, Christine; Ma, Cathleen; Strauss, Steven H; French, Darla; Meilan, Richard; Busov, Victor B

    2012-09-01

    This study describes functional characterization of two putative poplar PHOTOPERIOD RESPONSE 1 (PHOR1) orthologues. The expression and sequence analyses indicate that the two poplar genes diverged, at least partially, in function. PtPHOR1_1 is most highly expressed in roots and induced by short days, while PtPHOR1_2 is more uniformly expressed throughout plant tissues and is not responsive to short days. The two PHOR1 genes also had distinct effects on shoot and root growth when their expression was up- and downregulated transgenically. PtPHOR1_1 effects were restricted to roots while PtPHOR1_2 had similar effects on aerial and below-ground development. Nevertheless, both genes seemed to be upregulated in transgenic poplars that are gibberellin-deficient and gibberellin-insensitive, suggesting interplay with gibberellin signalling. PHOR1 suppression led to increased starch accumulation in both roots and stems. The effect of PHOR1 suppression on starch accumulation was coupled with growth-inhibiting effects in both roots and shoots, suggesting that PHOR1 is part of a mechanism that regulates the allocation of carbohydrate to growth or storage in poplar. PHOR1 downregulation led to significant reduction of xylem formation caused by smaller fibres and vessels suggesting that PHOR1 likely plays a role in the growth of xylem cells.

  11. PHOTOPERIOD RESPONSE 1 (PHOR1)-like Genes Regulate Shoot/root Growth, Starch Accumulation, and Wood Formation in Populus

    PubMed Central

    Busov, Victor B.

    2012-01-01

    This study describes functional characterization of two putative poplar PHOTOPERIOD RESPONSE 1 (PHOR1) orthologues. The expression and sequence analyses indicate that the two poplar genes diverged, at least partially, in function. PtPHOR1_1 is most highly expressed in roots and induced by short days, while PtPHOR1_2 is more uniformly expressed throughout plant tissues and is not responsive to short days. The two PHOR1 genes also had distinct effects on shoot and root growth when their expression was up- and downregulated transgenically. PtPHOR1_1 effects were restricted to roots while PtPHOR1_2 had similar effects on aerial and below-ground development. Nevertheless, both genes seemed to be upregulated in transgenic poplars that are gibberellin-deficient and gibberellin-insensitive, suggesting interplay with gibberellin signalling. PHOR1 suppression led to increased starch accumulation in both roots and stems. The effect of PHOR1 suppression on starch accumulation was coupled with growth-inhibiting effects in both roots and shoots, suggesting that PHOR1 is part of a mechanism that regulates the allocation of carbohydrate to growth or storage in poplar. PHOR1 downregulation led to significant reduction of xylem formation caused by smaller fibres and vessels suggesting that PHOR1 likely plays a role in the growth of xylem cells. PMID:22915748

  12. Seasonal productivity in a population of migratory songbirds: why nest data are not enough

    USGS Publications Warehouse

    Streby, Henry M.; Andersen, David E.

    2011-01-01

    Population models for many animals are limited by a lack of information regarding juvenile survival. In particular, studies of songbird reproductive output typically terminate with the success or failure of nests, despite the fact that adults spend the rest of the reproductive season rearing dependent fledglings. Unless fledgling survival does not vary, or varies consistently with nest productivity, conclusions about population dynamics based solely on nest data may be misleading. During 2007 and 2008, we monitored nests and used radio telemetry to monitor fledgling survival for a population of Ovenbirds (Seiurus aurocapilla) in a managed-forest landscape in north-central Minnesota, USA. In addition to estimating nest and fledgling survival, we modeled growth for population segments partitioned by proximity to edges of non-nesting cover types (regenerating clearcuts). Nest survival was significantly lower, but fledgling survival was significantly higher, in 2007 than in 2008. Despite higher nest productivity in 2008, seasonal productivity (number of young surviving to independence per breeding female) was higher in 2007. Proximity to clearcut edge did not affect nest productivity. However, fledglings from nests near regenerating sapling-dominated clearcuts (7–20 years since harvest) had higher daily survival (0.992 ± 0.005) than those from nests in interior forest (0.978 ± 0.006), which in turn had higher daily survival than fledglings from nests near shrub-dominated clearcuts (≤6 years since harvest; 0.927 ± 0.030) in 2007, with a similar but statistically non-significant trend in 2008. Our population growth models predicted growth rates that differed by 2–39% (x¯ = 25%) from simpler models in which we replaced our estimates of first-year survival with one-half adult annual survival (an estimate commonly used in songbird population growth models). We conclude that nest productivity is an inadequate measure of songbird seasonal productivity, and that

  13. Short photoperiod-induced ovarian regression is mediated by apoptosis in Siberian hamsters (Phodopus sungorus)

    PubMed Central

    Moffatt-Blue, C S; Sury, J J; Young, Kelly A

    2009-01-01

    Siberian hamster reproduction is mediated by photoperiod-induced changes in gonadal activity. However, little is known about how photoperiod induces cellular changes in ovarian function. We hypothesized that exposing female hamsters to short (inhibitory) as opposed to long (control) photoperiods would induce an apoptosis-mediated disruption of ovarian function. Ovaries and plasma from hamsters exposed to either long (LD, 16 h light:8 h darkness) or short (SD, 8 h light:16 h darkness) days were collected during diestrus II after 3, 6, 9 and 12 weeks and processed for histology or RIA respectively. Apoptosis was assessed by in situ TUNEL and active caspase-3 protein immunolabeling. No significant differences were observed among LD hamsters for any parameter; therefore, these control data were pooled. SD exposure induced a decline in preantral follicles (P < 0.05), early antral/antral follicles (P < 0.01) and corpora lutea (P < 0.01) by week 12 as compared with LD. Terminal atretic follicles appeared by SD week 9; by week 12, these had become the predominant ovarian structures. Estradiol concentrations decreased by weeks 9 and 12 SD when compared with both LD and week-3 SD hamsters (P < 0.05); however, no changes were observed for progesterone. TUNEL-positive follicles in SD ovaries increased at week 3 and subsequently declined by week 12 as compared with LD ovaries (P < 0.01). Active capsase-3 protein immunostaining peaked at SD week 3 as compared with all other groups (P < 0.01). TUNEL and capsase-3 immunolabeling were localized to granulosa cells of late-preantral and early-antral/antral follicles. These data indicate that SD exposure rapidly induces follicular apoptosis in Siberian hamsters, which ultimately disrupts both estradiol secretion and folliculogenesis, resulting in the seasonal loss of ovarian function. PMID:16595728

  14. Phenology and growth adjustments of oil palm (Elaeis guineensis) to photoperiod and climate variability

    PubMed Central

    Legros, S.; Mialet-Serra, I.; Caliman, J.-P.; Siregar, F. A.; Clément-Vidal, A.; Dingkuhn, M.

    2009-01-01

    Background and Aims Oil palm flowering and fruit production show seasonal maxima whose causes are unknown. Drought periods confound these rhythms, making it difficult to analyse or predict dynamics of production. The present work aims to analyse phenological and growth responses of adult oil palms to seasonal and inter-annual climatic variability. Methods Two oil palm genotypes planted in a replicated design at two sites in Indonesia underwent monthly observations during 22 months in 2006–2008. Measurements included growth of vegetative and reproductive organs, morphology and phenology. Drought was estimated from climatic water balance (rainfall – potential evapotranspiration) and simulated fraction of transpirable soil water. Production history of the same plants for 2001–2005 was used for inter-annual analyses. Key Results Drought was absent at the equatorial Kandista site (0°55′N) but the Batu Mulia site (3°12′S) had a dry season with variable severity. Vegetative growth and leaf appearance rate fluctuated with drought level. Yield of fruit, a function of the number of female inflorescences produced, was negatively correlated with photoperiod at Kandista. Dual annual maxima were observed supporting a recent theory of circadian control. The photoperiod-sensitive phases were estimated at 9 (or 9 + 12 × n) months before bunch maturity for a given phytomer. The main sensitive phase for drought effects was estimated at 29 months before bunch maturity, presumably associated with inflorescence sex determination. Conclusion It is assumed that seasonal peaks of flowering in oil palm are controlled even near the equator by photoperiod response within a phytomer. These patterns are confounded with drought effects that affect flowering (yield) with long time-lag. Resulting dynamics are complex, but if the present results are confirmed it will be possible to predict them with models. PMID:19748909

  15. Nocturnal migratory songbirds adjust their travelling direction aloft: evidence from a radiotelemetry and radar study.

    PubMed

    Sjöberg, Sissel; Nilsson, Cecilia

    2015-06-01

    In order to fully understand the orientation behaviour of migrating birds, it is important to understand when birds set their travel direction. Departure directions of migratory passerines leaving stopover sites are often assumed to reflect the birds' intended travel directions, but this assumption has not been critically tested. We used data from an automated radiotelemetry system and a tracking radar at Falsterbo peninsula, Sweden, to compare the initial orientation of departing songbirds (recorded by radiotelemetry) with the orientation of songbird migrants in climbing and level flight (recorded by radar). We found that the track directions of birds at high altitudes and in level flight were more concentrated than the directions of departing birds and birds in climbing flight, which indicates that the birds adjust their travelling direction once aloft. This was further supported by a wide scatter of vanishing bearings in a subsample of radio-tracked birds that later passed an offshore radio receiver station 50 km southeast of Falsterbo. Track directions seemed to be more affected by winds in climbing compared with level flights, which may be explained by birds not starting to partially compensate for wind drift until they have reached cruising altitudes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  16. Songbird dynamics under the sea: acoustic interactions between humpback whales suggest song mediates male interactions.

    PubMed

    Cholewiak, Danielle M; Cerchio, Salvatore; Jacobsen, Jeff K; Urbán-R, Jorge; Clark, Christopher W

    2018-02-01

    The function of song has been well studied in numerous taxa and plays a role in mediating both intersexual and intrasexual interactions. Humpback whales are among few mammals who sing, but the role of sexual selection on song in this species is poorly understood. While one predominant hypothesis is that song mediates male-male interactions, the mechanism by which this may occur has never been explored. We applied metrics typically used to assess songbird interactions to examine song sequences and movement patterns of humpback whale singers. We found that males altered their song presentation in the presence of other singers; focal males increased the rate at which they switched between phrase types ( p  = 0.005), and tended to increase the overall evenness of their song presentation ( p  = 0.06) after a second male began singing. Two-singer dyads overlapped their song sequences significantly more than expected by chance. Spatial analyses revealed that change in distance between singers was related to whether both males kept singing ( p  = 0.012), with close approaches leading to song cessation. Overall, acoustic interactions resemble known mechanisms of mediating intrasexual interactions in songbirds. Future work should focus on more precisely resolving how changes in song presentation may be used in competition between singing males.

  17. Songbird dynamics under the sea: acoustic interactions between humpback whales suggest song mediates male interactions

    PubMed Central

    Cerchio, Salvatore; Jacobsen, Jeff K.; Urbán-R., Jorge

    2018-01-01

    The function of song has been well studied in numerous taxa and plays a role in mediating both intersexual and intrasexual interactions. Humpback whales are among few mammals who sing, but the role of sexual selection on song in this species is poorly understood. While one predominant hypothesis is that song mediates male–male interactions, the mechanism by which this may occur has never been explored. We applied metrics typically used to assess songbird interactions to examine song sequences and movement patterns of humpback whale singers. We found that males altered their song presentation in the presence of other singers; focal males increased the rate at which they switched between phrase types (p = 0.005), and tended to increase the overall evenness of their song presentation (p = 0.06) after a second male began singing. Two-singer dyads overlapped their song sequences significantly more than expected by chance. Spatial analyses revealed that change in distance between singers was related to whether both males kept singing (p = 0.012), with close approaches leading to song cessation. Overall, acoustic interactions resemble known mechanisms of mediating intrasexual interactions in songbirds. Future work should focus on more precisely resolving how changes in song presentation may be used in competition between singing males. PMID:29515847

  18. Soybean fruit development and set at the node level under combined photoperiod and radiation conditions

    PubMed Central

    Nico, Magalí; Mantese, Anita I.; Miralles, Daniel J.; Kantolic, Adriana G.

    2016-01-01

    In soybean, long days during post-flowering increase seed number. This positive photoperiodic effect on seed number has been previously associated with increments in the amount of radiation accumulated during the crop cycle because long days extend the duration of the crop cycle. However, evidence of intra-nodal processes independent of the availability of assimilates suggests that photoperiodic effects at the node level might also contribute to pod set. This work aims to identify the main mechanisms responsible for the increase in pod number per node in response to long days; including the dynamics of flowering, pod development, growth and set at the node level. Long days increased pods per node on the main stems, by increasing pods on lateral racemes (usually dominated positions) at some main stem nodes. Long days lengthened the flowering period and thereby increased the number of opened flowers on lateral racemes. The flowering period was prolonged under long days because effective seed filling was delayed on primary racemes (dominant positions). Long days also delayed the development of flowers into pods with filling seeds, delaying the initiation of pod elongation without modifying pod elongation rate. The embryo development matched the external pod length irrespective of the pod’s chronological age. These results suggest that long days during post-flowering enhance pod number per node through a relief of the competition between pods of different hierarchy within the node. The photoperiodic effect on the development of dominant pods, delaying their elongation and therefore postponing their active growth, extends flowering and allows pod set at positions that are usually dominated. PMID:26512057

  19. Soybean fruit development and set at the node level under combined photoperiod and radiation conditions.

    PubMed

    Nico, Magalí; Mantese, Anita I; Miralles, Daniel J; Kantolic, Adriana G

    2016-01-01

    In soybean, long days during post-flowering increase seed number. This positive photoperiodic effect on seed number has been previously associated with increments in the amount of radiation accumulated during the crop cycle because long days extend the duration of the crop cycle. However, evidence of intra-nodal processes independent of the availability of assimilates suggests that photoperiodic effects at the node level might also contribute to pod set. This work aims to identify the main mechanisms responsible for the increase in pod number per node in response to long days; including the dynamics of flowering, pod development, growth and set at the node level. Long days increased pods per node on the main stems, by increasing pods on lateral racemes (usually dominated positions) at some main stem nodes. Long days lengthened the flowering period and thereby increased the number of opened flowers on lateral racemes. The flowering period was prolonged under long days because effective seed filling was delayed on primary racemes (dominant positions). Long days also delayed the development of flowers into pods with filling seeds, delaying the initiation of pod elongation without modifying pod elongation rate. The embryo development matched the external pod length irrespective of the pod's chronological age. These results suggest that long days during post-flowering enhance pod number per node through a relief of the competition between pods of different hierarchy within the node. The photoperiodic effect on the development of dominant pods, delaying their elongation and therefore postponing their active growth, extends flowering and allows pod set at positions that are usually dominated. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  20. Automated telemetry reveals age specific differences in flight duration and speed are driven by wind conditions in a migratory songbird.

    PubMed

    Mitchell, Greg W; Woodworth, Bradley K; Taylor, Philip D; Norris, D Ryan

    2015-01-01

    Given that winds encountered on migration could theoretically double or half the energy expenditure of aerial migrants, there should be strong selection on behaviour in relation to wind conditions aloft. However, evidence suggests that juvenile songbirds are less choosy about wind conditions at departure relative to adults, potentially increasing energy expenditure during flight. To date, there has yet to be a direct comparison of flight efficiency between free-living adult and juvenile songbirds during migration in relation to wind conditions aloft, likely because of the challenges of following known aged individual songbirds during flight. We used an automated digital telemetry array to compare the flight efficiency of adult and juvenile Savannah sparrows (Passerculus sandwichensis) as they flew nearly 100 km during two successive stages of their fall migration; a departure flight from their breeding grounds out over the ocean and then a migratory flight along a coast. Using a multilevel path modelling framework, we evaluated the effects of age, flight stage, tailwind component, and crosswind component on flight duration and groundspeed. We found that juveniles departed under wind conditions that were less supportive relative to adults and that this resulted in juveniles taking 1.4 times longer to complete the same flight trajectories as adults. We did not find an effect of age on flight duration or groundspeed after controlling for wind conditions aloft, suggesting that both age groups were flying at similar airspeeds. We also found that groundspeeds were 1.7 times faster along the coast than over the ocean given more favourable tailwinds along the coast and because birds appeared to be climbing in altitude over the ocean, diverting some energy from horizontal to vertical movement. Our results provide the first evidence that adult songbirds have considerably more efficient migratory flights than juveniles, and that this efficiency is driven by the selection of

  1. Effects of CO2 Concentration on Leaf Photosynthesis and Stomatal Conductance of Potatoes Grown Under Different Irradiance Levels and Photoperiods

    NASA Technical Reports Server (NTRS)

    Wheeler, R. M.; Fitzpatrick, A. H.; Tibbitts, T. W.

    2012-01-01

    Potato (Solanum tuberosum L.) cvs. Russet Burbank, Denali, and Norland, were grown in environmental rooms controlled at approx 350 micro mol/mol (ambient during years 1987/1988) and 1000 micro mol/mol (enriched) CO2 concentrations. Plants and electric lamps were arranged to provide two irradiance zones, 400 and 800 micro mol/mol/square m/S PPF and studies were repeated using two photoperiods (12-h light / 12-h dark and continuous light). Leaf photosynthetic rates and leaf stomatal conductance were measured using fully expanded, upper canopy leaves at weekly intervals throughout growth (21 through 84 days after transplanting). Increasing the CO2 from approx 350 to 1000 micro mol/mol under the 12-h photoperiod increased leaf photosynthetic rates by 39% at 400 micro mol/mol/square m/S PPF and 27% at 800 micro mol/mol/square m/S PPF. Increasing the CO2 from approx 350 to 1000 micro mol/mol under continuous light decreased leaf photosynthetic rates by 7% at 400 micro mol/mol/square m/S PPF and 13% at 800 micro mol/mol/square m/S PPF. Increasing the CO2 from approx 350 to 1000 micro mol/mol under the 12-h photoperiod plants decreased stomatal conductance by an average of 26% at 400 micro mol/mol/square m/S PPF and 42% at 800 micro mol/mol/square m/S PPF. Under continuous light, CO2 enrichment resulted in a small increase (2%) of stomatal conductance at 400 micro mol/mol/square m/S PPF, and a small decrease (3%) at 800 micro mol/mol/square m/S PPF. Results indicate that CO2 enrichment under the 12-h photoperiod showed the expected increase in photosynthesis and decrease in stomatal conductance for a C3 species like potato, but the decreases in leaf photosynthetic rates and minimal effect on conductance from CO2 enrichment under continuous light were not expected. The plant leaves under continuous light showed more chlorosis and some rusty flecking versus plants under the 12-h photoperiod, suggesting the continuous light was more stressful on the plants. The increased

  2. Notes and Discussion: White-tailed deer (Odocoileus virginianus) predation on grassland songbird nestlings

    USGS Publications Warehouse

    Pietz, P.J.; Granfors, D.A.

    2000-01-01

    White-tailed deer (odocoileus virginianus) were videotaped depredating four songbird nests in grassland habitats in southeastern and northcentral North Dakota, 1996-1999. Deer ate two Savannah sparrow (Passerculus sandwichensis), two grasshopper sparrow (Ammodramus savannarum), one clay-colored sparrow (Spizella pallida), one red-winged blackbird (Agelaius phoeniceus) and three brown-headed cowbird (Molothrus ater) nestlings. Deer removed nestlings quickly (5-19 sec/nest) at night (22:00 to 05:17 Central Daylight Time) and left no evidence of predation. Although probably opportunistic, deer predations clearly were deliberate and likely are more common than generally believed.

  3. Morphofunctional evidence for the involvement of hypothalamic dopaminergic and GABAergic neurons in the mechanisms of photoperiod-dependent prolactin release in the mink.

    PubMed

    Boissin-Agasse, L; Tappaz, M; Roch, G; Gril, C; Boissin, J

    1991-06-01

    This study was designed to examine possible relationships between the photoperiodic regulation of prolactin secretion and the activity of dopaminergic and GABAergic neurons projecting to the external layer of the median eminence. The study was carried out on the mink whose remarkable photosensitivity has been clearly demonstrated. The animals were reared in short (4L:20D) or long (20L:4D) photoperiods. The experiment began in November when day length is short (9.5 h). Dopaminergic and GABAergic neurons were studied using immunocytochemical methods allowing evaluation of the immunoreactivities of tyrosine hydroxylase (TH) and glutamate decarboxylase (GAD), which are respective markers of these neurons. The results were quantified by image analysis. The plasma prolactin level of animals maintained in 4L:20D decreased after 60 days and TH and GAD immunoreactivity were strongly stimulated. After 110 days, the prolactin concentration and TH and GAD immunoreactivity recovered their starting levels. In animals maintained in 20L:4D, the prolactin level was 3 times higher than at the beginning of the photoperiodic treatment but only dopaminergic neurons showed a change, i.e. a decrease in immunoreactivity. At the end of the experiment, prolactin secretion was no longer affected by the stimulatory effect of long-day treatment, and TH immunoreactivity remained low. These results confirm the generally accepted concept that dopaminergic neurons are potent PIF-producing components. GABAergic hypothalamic system appears to be implicated in photoperiodic PRL regulation, but this remains to be clearly demonstrated.

  4. Melatonin delays clutch initiation in a wild songbird

    PubMed Central

    Greives, Timothy J.; Kingma, Sjouke A.; Beltrami, Giulia; Hau, Michaela

    2012-01-01

    The hormone melatonin is known to play an important role in regulating many seasonal changes in physiology, morphology and behaviour. In birds, unlike in mammals, melatonin has thus far been thought to play little role in timing seasonal reproductive processes. This view is mainly derived from laboratory experiments on male birds. This study tests whether melatonin is capable of influencing the timing of clutch initiation in wild female songbirds. Free-living female great tits (Parus major) treated with melatonin-filled implants prior to the breeding season initiated their first clutch of the season significantly later than females carrying an empty implant. Melatonin treatment did not affect clutch size. Further, melatonin treatment did not delay the onset of daily activity in the wild nor adversely affect body mass in captivity compared with controls. These data suggest a previously unknown role for this hormone in regulating the timing of clutch initiation in the wild. PMID:22171024

  5. Fat, weather, and date affect migratory songbirds' departure decisions, routes, and time it takes to cross the Gulf of Mexico.

    PubMed

    Deppe, Jill L; Ward, Michael P; Bolus, Rachel T; Diehl, Robert H; Celis-Murillo, Antonio; Zenzal, Theodore J; Moore, Frank R; Benson, Thomas J; Smolinsky, Jaclyn A; Schofield, Lynn N; Enstrom, David A; Paxton, Eben H; Bohrer, Gil; Beveroth, Tara A; Raim, Arlo; Obringer, Renee L; Delaney, David; Cochran, William W

    2015-11-17

    Approximately two thirds of migratory songbirds in eastern North America negotiate the Gulf of Mexico (GOM), where inclement weather coupled with no refueling or resting opportunities can be lethal. However, decisions made when navigating such features and their consequences remain largely unknown due to technological limitations of tracking small animals over large areas. We used automated radio telemetry to track three songbird species (Red-eyed Vireo, Swainson's Thrush, Wood Thrush) from coastal Alabama to the northern Yucatan Peninsula (YP) during fall migration. Detecting songbirds after crossing ∼1,000 km of open water allowed us to examine intrinsic (age, wing length, fat) and extrinsic (weather, date) variables shaping departure decisions, arrival at the YP, and crossing times. Large fat reserves and low humidity, indicative of beneficial synoptic weather patterns, favored southward departure across the Gulf. Individuals detected in the YP departed with large fat reserves and later in the fall with profitable winds, and flight durations (mean = 22.4 h) were positively related to wind profit. Age was not related to departure behavior, arrival, or travel time. However, vireos negotiated the GOM differently than thrushes, including different departure decisions, lower probability of detection in the YP, and longer crossing times. Defense of winter territories by thrushes but not vireos and species-specific foraging habits may explain the divergent migratory behaviors. Fat reserves appear extremely important to departure decisions and arrival in the YP. As habitat along the GOM is degraded, birds may be limited in their ability to acquire fat to cross the Gulf.

  6. Host plant, temperature, and photoperiod effects on ovipositional preference of Frankliniella occidentalis and Frankliniella fusca (Thysanoptera: Thripidae).

    PubMed

    Chaisuekul, C; Riley, D G

    2005-12-01

    Host plant effects of tomato, Lycopersicon esculentum Mill., and chickweed, Stellaria media (L.) Vill., foliage infected and uninfected with Tomato spotted wilt virus (family Bunyaviridae, genus Tospovirus, TSWV) on the ovipositional preferences of western flower thrips, Frankliniella occidentalis (Pergande), and tobacco thrips, Frankliniella fusca (Hinds), were investigated for whole plants in the greenhouse. In addition, the preference for leaf disks from the same host plants was investigated under a range of temperatures, 15-30 degrees C at a photoperiod of 12:12 (L:D) h, and at three photoperiods, 6:18, 12:12, and 18:6, at 20 degrees C in no-choice and choice studies conducted in growth chambers. In a choice test, F. fusca oviposited significantly more eggs per whole plant foliage over a 7-d period than F. occidentalis by an average ratio of 3:1 over both tomato and chickweed. The optimum temperature for oviposition of F. occidentalis and F. fusca was 24.5 and 24.9 degrees C, respectively. Both species laid significantly more eggs under the longest daylight hours tested, 18:6, in the choice study. Temperature and photoperiod did not significantly interact in terms of thrips ovipositional preference. Ovipositional preference for chickweed or tomato foliage was different for each thrips species in the choice and no-choice tests. However, both thrips species laid significantly more eggs per square centimeter of leaf area in chickweed than in tomato in the whole plant choice test.

  7. Arabidopsis Glutaredoxin S17 and Its Partner, the Nuclear Factor Y Subunit C11/Negative Cofactor 2α, Contribute to Maintenance of the Shoot Apical Meristem under Long-Day Photoperiod1

    PubMed Central

    Knuesting, Johannes; Riondet, Christophe; Kruse, Inga; Bécuwe, Noëlle; König, Nicolas; Berndt, Carsten; Tourrette, Sébastien; Guilleminot-Montoya, Jocelyne; Herrero, Enrique; Gaymard, Frédéric; Balk, Janneke; Belli, Gemma; Reichheld, Jean-Philippe; Rouhier, Nicolas; Rey, Pascal

    2015-01-01

    Glutaredoxins (GRXs) catalyze the reduction of protein disulfide bonds using glutathione as a reductant. Certain GRXs are able to transfer iron-sulfur clusters to other proteins. To investigate the function of Arabidopsis (Arabidopsis thaliana) GRXS17, we applied a strategy combining biochemical, genetic, and physiological approaches. GRXS17 was localized in the nucleus and cytosol, and its expression was elevated in the shoot meristems and reproductive tissues. Recombinant GRXS17 bound Fe2S2 clusters, a property likely contributing to its ability to complement the defects of a Baker’s yeast (Saccharomyces cerevisiae) strain lacking the mitochondrial GRX5. However, a grxs17 knockout Arabidopsis mutant exhibited only a minor decrease in the activities of iron-sulfur enzymes, suggesting that its primary function is as a disulfide oxidoreductase. The grxS17 plants were sensitive to high temperatures and long-day photoperiods, resulting in elongated leaves, compromised shoot apical meristem, and delayed bolting. Both environmental conditions applied simultaneously led to a growth arrest. Using affinity chromatography and split-Yellow Fluorescent Protein methods, a nuclear transcriptional regulator, the Nuclear Factor Y Subunit C11/Negative Cofactor 2α (NF-YC11/NC2α), was identified as a GRXS17 interacting partner. A mutant deficient in NF-YC11/NC2α exhibited similar phenotypes to grxs17 in response to photoperiod. Therefore, we propose that GRXS17 interacts with NF-YC11/NC2α to relay a redox signal generated by the photoperiod to maintain meristem function. PMID:25699589

  8. Effects of lighting pattern and photoperiod on egg production and egg quality of a native chicken under free-range condition.

    PubMed

    Geng, A L; Zhang, Y; Zhang, J; Wang, H H; Chu, Q; Liu, H G

    2018-04-14

    The paper aimed to study the effects of lighting pattern and photoperiod alone and in combination on egg production, egg quality in Beijing You Chicken (BYC). A total of 630 19-wk-old BYC laying hens were randomly allocated to 6 groups with 105 birds each, 3 replicates per group, reared in individually lit floor pens with separate outdoor areas. A 2 × 3 factorial experiment (2 lighting patterns: continuous and intermittent lighting; 3 photoperiods: 16, 14, 12 h) was arranged, including 16L:8D (6:00 to 22:00) for group 1; 12L:2D:4L:6D (6:00 to 18:00, 20:00 to 24:00) for group 2; 14L:10D (6:00 to 20:00) for group 3; 10L:2D:4L:8D (6:00 to 16:00, 18:00 to 22:00) for group 4; 12L:12D (6:00 to 18:00) for group 5, and 8L:4D:4L:8D (6:00 to 14:00, 18:00 to 22:00) for group 6, respectively. Egg production parameters were calculated for 22 to 43, 44 to 57, and 22 to 57 wk, and egg quality parameters were measured at the end of 37 and 57 wk. The results showed that the egg production of BYC was not significantly affected by lighting pattern, photoperiod alone, or in combination during 22 to 43 and 22 to 57 wk (P > 0.05), but average feed intake in 12 h groups was significantly higher than those in 14 and 16 h groups during 22 to 43 and 22 to 57 wk (P < 0.05). Egg mass and feed egg ratio were significantly affected by lighting pattern, photoperiod alone, and in combination during 44 to 57 wk (P < 0.05). Egg mass was significantly higher (P = 0.05) and feed egg ratio was significantly lower (P = 0.03) in continuous groups than in intermittent groups. There were significant effects for eggshell thickness, albumen height, haugh unit, and egg grade by lighting pattern alone (P < 0.05) at 37 wk. The study suggested that 1) the egg production was not significantly affected by lighting pattern alone during 22 to 57 wk (P > 0.05), but the photoperiod significantly affected average feed intake (P < 0.05); 2) continuous lighting is better for the egg production during 44 to 57 wk

  9. Evaluation of the growth of the bursa of fabricius in broilers reared under different light photoperiods

    USDA-ARS?s Scientific Manuscript database

    Previous studies have investigated the interaction of different light sources and light intensity. Studies are lacking concerning the effect of different light sources and photoperiods on broiler growth and health. The results reported here are a part of a larger study to evaluate the interaction of...

  10. Photoperiod- and temperature-mediated control of phenology in trees - a molecular perspective.

    PubMed

    Singh, Rajesh Kumar; Svystun, Tetiana; AlDahmash, Badr; Jönsson, Anna Maria; Bhalerao, Rishikesh P

    2017-01-01

    Contents 511 I. 511 II. 512 III. 513 IV. 513 V. 517 VI. 517 VII. 521 VIII. 521 Acknowledgements 521 References 521 SUMMARY: Trees growing in boreal and temperate regions synchronize their growth with seasonal climatic changes in adaptive responses that are essential for their survival. These trees cease growth before the winter and establish a dormant state during which growth cessation is maintained by repression of responses to growth-promotive signals. Reactivation of growth in the spring follows the release from dormancy promoted by prolonged exposure to low temperature during the winter. The timing of the key events and regulation of the molecular programs associated with the key stages of the annual growth cycle are controlled by two main environmental cues: photoperiod and temperature. Recently, key components mediating photoperiodic control of growth cessation and bud set have been identified, and striking similarities have been observed in signaling pathways controlling growth cessation in trees and floral transition in Arabidopsis. Although less well understood, the regulation of bud dormancy and bud burst may involve cell-cell communication and chromatin remodeling. Here, we discuss current knowledge of the molecular-level regulation of the annual growth cycle of woody trees in temperate and boreal regions, and identify key questions that need to be addressed in the future. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  11. Biocapture of CO₂ by Different Microalgal-Based Technologies for Biogas Upgrading and Simultaneous Biogas Slurry Purification under Various Light Intensities and Photoperiods.

    PubMed

    Guo, Pengfei; Zhang, Yuejin; Zhao, Yongjun

    2018-03-15

    Abstract : Co-cultivation of microalgae and microbes for pollutant removal from sewage is considered as an effective wastewater treatment method. The aim of this study is to screen the optimal photoperiod, light intensity and microalgae co-cultivation method for simultaneously removing nutrients in biogas slurry and capturing CO₂ in biogas. The microalgae-fungi pellets are deemed to be a viable option because of their high specific growth rate and nutrient and CO 2 removal efficiency under the photoperiod of 14 h light:10 h dark. The order of both the biogas slurry purification and biogas upgrading is ranked the same, that is Chlorella vulga ris - Ganoderma lucidum > Chlorella vulga ris -activated sludge > Chlorella vulgaris under different light intensities. For all cultivation methods, the moderate light intensity of 450 μmol m -2 s -1 is regarded as the best choice. This research revealed that the control of photoperiod and light intensity can promote the biological treatment process of biogas slurry purification and biogas upgrading using microalgal-based technology.

  12. Carcass composition and mammary development responses to photoperiod and plane of nutrition in Holstein heifers.

    PubMed

    Petitclerc, D; Chapin, L T; Tucker, H A

    1984-04-01

    Twenty prepubertal heifers (averaging 155 kg body weight) were assigned to one of four treatment groups in an experiment of 2 X 2 factorial design. The main effects were photoperiods of 8 h light:16 h dark (8L:16D) vs 16L:8D, and LOW vs HIGH plane of nutrition. Heifers on the LOW plane of nutrition were fed to achieve a growth rate of approximately .7 kg/d; daily feed intake was restricted with no orts and was identical in both groups of heifers subjected to either 8 or 16 h of light daily. Heifers on the HIGH plane of nutrition were fed ad libitum to achieve a growth rate greater than 1 kg/d. All heifers were slaughtered during the luteal phase of an estrous cycle at an average body weight of 337, 334, 360 and 349 kg for 8L:16D-LOW plane, 16L:8D-LOW plane, 8L:16D-HIGH plane and 16L:8D-HIGH plane groups, respectively. Average time on treatment was 233, 236, 206 and 181 d and average estimated carcass weight gain was .39, .40, .55 and .61 kg/d, respectively. Within LOW or HIGH planes of nutrition, photoperiod did not affect live body weight gains. A photoperiod of 16L:8D, compared with 8L:16D, increased protein content in the 9-10-11th rib section of heifers on HIGH nutrition (16.2 vs 14.6%), but not in heifers fed the LOW plane of nutrition (15.5 vs 16.1%). However, within 8L:16D groups, HIGH plane reduced rib section protein content as compared with LOW plane of nutrition (14.6 vs 16.1%); there was no difference observed within 16L:8D groups.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Breathing and Vocal Control: The Respiratory System as both a Driver and Target of Telencephalic Vocal Motor Circuits in Songbirds

    PubMed Central

    Schmidt, Marc F.; McLean, Judith; Goller, Franz

    2011-01-01

    The production of vocalizations is intimately linked to the respiratory system. Despite our understanding of neural circuits that generate normal respiratory patterns, very little is understood regarding how these ponto-medullary circuits become engaged during vocal production. Songbirds offer a potentially powerful model system for addressing this relationship. Songs dramatically alter the respiratory pattern in ways that are often highly predictable and songbirds have a specialized telencephalic vocal motor circuit that provides massive innervation to a brainstem respiratory network that shares many similarities with its mammalian counterpart. In this review, we highlight interactions between the song motor circuit and the respiratory system, describing how both systems likely interact to produce the complex respiratory patterns that are observed during vocalization. We also discuss how the respiratory system, through its bilateral bottom-up projections to thalamus, might play a key role in sending precisely timed signals that synchronize premotor activity in both hemispheres. PMID:21984733

  14. Migration phenology and breeding success are predicted by methylation of a photoperiodic gene in the barn swallow

    PubMed Central

    Saino, Nicola; Ambrosini, Roberto; Albetti, Benedetta; Caprioli, Manuela; De Giorgio, Barbara; Gatti, Emanuele; Liechti, Felix; Parolini, Marco; Romano, Andrea; Romano, Maria; Scandolara, Chiara; Gianfranceschi, Luca; Bollati, Valentina; Rubolini, Diego

    2017-01-01

    Individuals often considerably differ in the timing of their life-cycle events, with major consequences for individual fitness, and, ultimately, for population dynamics. Phenological variation can arise from genetic effects but also from epigenetic modifications in DNA expression and translation. Here, we tested if CpG methylation at the poly-Q and 5′-UTR loci of the photoperiodic Clock gene predicted migration and breeding phenology of long-distance migratory barn swallows (Hirundo rustica) that were tracked year-round using light-level geolocators. Increasing methylation at Clock poly-Q was associated with earlier spring departure from the African wintering area, arrival date at the European breeding site, and breeding date. Higher methylation levels also predicted increased breeding success. Thus, we showed for the first time in any species that CpG methylation at a candidate gene may affect phenology and breeding performance. Methylation at Clock may be a candidate mechanism mediating phenological responses of migratory birds to ongoing climate change. PMID:28361883

  15. Migration phenology and breeding success are predicted by methylation of a photoperiodic gene in the barn swallow.

    PubMed

    Saino, Nicola; Ambrosini, Roberto; Albetti, Benedetta; Caprioli, Manuela; De Giorgio, Barbara; Gatti, Emanuele; Liechti, Felix; Parolini, Marco; Romano, Andrea; Romano, Maria; Scandolara, Chiara; Gianfranceschi, Luca; Bollati, Valentina; Rubolini, Diego

    2017-03-31

    Individuals often considerably differ in the timing of their life-cycle events, with major consequences for individual fitness, and, ultimately, for population dynamics. Phenological variation can arise from genetic effects but also from epigenetic modifications in DNA expression and translation. Here, we tested if CpG methylation at the poly-Q and 5'-UTR loci of the photoperiodic Clock gene predicted migration and breeding phenology of long-distance migratory barn swallows (Hirundo rustica) that were tracked year-round using light-level geolocators. Increasing methylation at Clock poly-Q was associated with earlier spring departure from the African wintering area, arrival date at the European breeding site, and breeding date. Higher methylation levels also predicted increased breeding success. Thus, we showed for the first time in any species that CpG methylation at a candidate gene may affect phenology and breeding performance. Methylation at Clock may be a candidate mechanism mediating phenological responses of migratory birds to ongoing climate change.

  16. Multiple effects of circadian dysfunction induced by photoperiod shifts: alterations in context memory and food metabolism in the same subjects.

    PubMed

    McDonald, Robert J; Zelinski, Erin L; Keeley, Robin J; Sutherland, Dylan; Fehr, Leah; Hong, Nancy S

    2013-06-13

    Humans exposed to shiftwork conditions have been reported to have increased susceptibility to various health problems including various forms of dementia, cancer, heart disease, and metabolic disorders related to obesity. The present experiments assessed the effects of circadian disruption on learning and memory function and various food related processes including diet consumption rates, food metabolism, and changes in body weight. These experiments utilized a novel variant of the conditioned place preference task (CPP) that is normally used to assess Pavlovian associative learning and memory processes produced via repeated context-reward pairings. For the present experiments, the standard CPP paradigm was modified in that both contexts were paired with food, but the dietary constituents of the food were different. In particular, we were interested in whether rats could differentiate between two types of carbohydrates, simple (dextrose) and complex (starch). Consumption rates for each type of carbohydrate were measured throughout training. A test of context preference without the food present was also conducted. At the end of behavioral testing, a fasting glucose test and a glucose challenge test were administered. Chronic photoperiod shifting resulted in impaired context learning and memory processes thought to be mediated by a neural circuit centered on the hippocampus. The results also showed that preferences for the different carbohydrate diets were altered in rats experiencing photoperiod shifting in that they maintained an initial preference for the simple carbohydrate throughout training. Lastly, photoperiod shifting resulted in changes in fasting blood glucose levels and elicited weight gain. These results show that chronic photoperiod shifting, which likely resulted in circadian dysfunction, impairs multiple functions of the brain and/or body in the same individual. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

  17. Effect of Ppd-1 on the expression of flowering-time genes in vegetative and reproductive growth stages of wheat.

    PubMed

    Kitagawa, Satoshi; Shimada, Sanae; Murai, Koji

    2012-01-01

    The photoperiod sensitivity gene Ppd-1 influences the timing of flowering in temperate cereals such as wheat and barley. The effect of Ppd-1 on the expression of flowering-time genes was assessed by examining the expression levels of the vernalization genes VRN1 and VRN3/WFT and of two CONSTANS-like genes, WCO1 and TaHd1, during vegetative and reproductive growth stages. Two near-isogenic lines (NILs) were used: the first carried a photoperiod-insensitive allele of Ppd-1 (Ppd-1a-NIL), the other, a photoperiod-sensitive allele (Ppd-1b-NIL). We found that the expression pattern of VRN1 was similar in Ppd-1a-NIL and Ppd-1b-NIL plants, suggesting that VRN1 is not regulated by Ppd-1. Under long day conditions, VRN3/WFT showed similar expression patterns in Ppd-1a-NIL and Ppd-1b-NIL plants. However, expression differed greatly under short day conditions: VRN3/WFT expression was detected in Ppd-1a-NIL plants at the 5-leaf stage when they transited from vegetative to reproductive growth; very low expression was present in Ppd-1b-NIL throughout all growth stages. Thus, the Ppd-1b allele acts to down-regulate VRN3/WFT under short day conditions. WCO1 showed high levels of expression at the vegetative stage, which decreased during the phase transition and reproductive growth stages in both Ppd-1a-NIL and Ppd-1b-NIL plants under short day conditions. By contrast to WCO1, TaHd1 was up-regulated during the reproductive stage. The level of TaHd1 expression was much higher in Ppd-1a-NIL than the Ppd-1b-NIL plants, suggesting that the Ppd-1b allele down-regulates TaHd1 under short day conditions. The present study indicates that down-regulation of VRN3/WFT together with TaHd1 is the cause of late flowering in the Ppd-1b-NIL plants under short day conditions.

  18. Photoperiod and temperature constraints on the relationship between the photochemical reflectance index and the light use efficiency of photosynthesis in Pinus strobus

    PubMed Central

    Fréchette, Emmanuelle; Chang, Christine Yao-Yun; Ensminger, Ingo

    2016-01-01

    The photochemical reflectance index (PRI) is a proxy for the activity of the photoprotective xanthophyll cycle and photosynthetic light use efficiency (LUE) in plants. Evergreen conifers downregulate photosynthesis in autumn in response to low temperature and shorter photoperiod, and the dynamic xanthophyll cycle-mediated non-photochemical quenching (NPQ) is replaced by sustained NPQ. We hypothesized that this shift in xanthophyll cycle-dependent energy partitioning during the autumn is the cause for variations in the PRI–LUE relationship. In order to test our hypothesis, we characterized energy partitioning and pigment composition during a simulated summer–autumn transition in a conifer and assessed the effects of temperature and photoperiod on the PRI–LUE relationship. We measured gas exchange, chlorophyll fluorescence and leaf reflectance during the photosynthetic downregulation in Pinus strobus L. seedlings exposed to low temperature/short photoperiod or elevated temperature/short photoperiod conditions. Shifts in energy partitioning during simulated autumn were observed when the pools of chlorophylls decreased and pools of photoprotective carotenoids increased. On a seasonal timescale, PRI was controlled by carotenoid pool sizes rather than xanthophyll cycle dynamics. Photochemical reflectance index variation under cold autumn conditions mainly reflected long-term pigment pool adjustments associated with sustained NPQ, which impaired the PRI–LUE relationship. Exposure to warm autumn conditions prevented the induction of sustained NPQ but still impaired the PRI–LUE relationship. We therefore conclude that alternative zeaxanthin-independent NPQ mechanisms, which remain undetected by the PRI, are present under both cold and warm autumn conditions, contributing to the discrepancy in the PRI–LUE relationship during autumn. PMID:26846980

  19. Post-independence fledgling ecology in a migratory songbird: Implications for breeding-grounds conservation

    USGS Publications Warehouse

    Streby, H.M.; Peterson, S.M.; Kramer, G.R.; Anderson, D.E.

    2014-01-01

    For migratory songbirds, breeding-grounds conservation and management plans are generally focused on habitat associated with locations of singing males and sometimes nesting females. However, habitat structure is often different in areas used for raising fledglings compared with areas used for song territories, and very little is known about habitat use by fledglings after independence from adult care. From 2010 to 2012, we used radiotelemetry to monitor 68 fledgling golden-winged warblers Vermivora chrysoptera after independence from adult care in mixed managed forests of Minnesota, US and Manitoba, Canada. This species is of high conservation concern in the US, is listed as threatened in Canada and is listed as near threatened on the International Union for Conservation of Nature Red List. We assessed distance and orientation of independent fledgling movements and we used compositional analysis to test for selection among cover types. Fledglings of this species, commonly described as a shrubland specialist, selected mature forest (78% of locations) over all other cover types, and foraged in forest canopy and understory in mixed-species flocks. Fledgling golden-winged warbler movements were apparently associated with habitat optimization (although prioritizing foraging over predator avoidance), and likely not with commencement of migration, or scouting future breeding territories. Ten days after independence, fledglings were an average of 1238 m north of their nest, which may be related to homing-target formation and the species' northward range expansion. We conclude that consideration for independent fledgling habitat associations is necessary for developing full-fledged forest management plans on the breeding grounds of migratory songbirds.

  20. Testosterone-dependency of male solo song in a duetting songbird--evidence from females.

    PubMed

    Voigt, Cornelia; Leitner, Stefan

    2013-01-01

    For male songbirds of the temperate zone there is a tight link between seasonal song behaviour and circulating testosterone levels. Such a relationship does not seem to hold for tropical species where singing can occur year-round and breeding seasons are often extended. White-browed sparrow weavers (Plocepasser mahali) are cooperatively breeding songbirds with a dominant breeding pair and male and female subordinates found in eastern and southern Africa. Each group defends an all-purpose territory year-round. While all group members sing duets and choruses, the most dominant male additionally sings a solo song that comprises a distinct and large syllable repertoire. Previous studies suggested this type of song being associated with reproduction but failed to support a relationship with males' circulating testosterone levels. The present study aimed to investigate the steroid hormone sensitivity of the solo song in more detail. We found that dominant males had significantly higher circulating testosterone levels than subordinates during the early and late breeding seasons. No changes in solo song characteristics were found between both time points. Further, experimental implantation of captive adult females with exogenous testosterone induced solo singing within one week of treatment. Such females produced male-typical song regarding overall structure and syllable composition. Sex differences existed, however, concerning singing activity, repertoire size and temporal organisation of song. These results suggest that solo singing in white-browed sparrow weavers is under the control of gonadal steroid hormones. Moreover, the behaviour is not male-specific but can be activated in females under certain conditions. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. ZENK expression following conspecific and heterospecific playback in the zebra finch auditory forebrain.

    PubMed

    Scully, Erin N; Hahn, Allison H; Campbell, Kimberley A; McMillan, Neil; Congdon, Jenna V; Sturdy, Christopher B

    2017-07-28

    Zebra finches (Taeniopygia guttata) are sexually dimorphic songbirds, not only in appearance but also in vocal production: while males produce both calls and songs, females only produce calls. This dimorphism provides a means to contrast the auditory perception of vocalizations produced by songbird species of varying degrees of relatedness in a dimorphic species to that of a monomorphic species, species in which both males and females produce calls and songs (e.g., black-capped chickadees, Poecile atricapillus). In the current study, we examined neuronal expression after playback of acoustically similar hetero- and conspecific calls produced by species of differing phylogenetic relatedness to our subject species, zebra finch. We measured the immediate early gene (IEG) ZENK in two auditory areas of the forebrain (caudomedial mesopallium, CMM, and caudomedial nidopallium, NCM). We found no significant differences in ZENK expression in either male or female zebra finches regardless of playback condition. We also discuss comparisons between our results and the results of a previous study conducted by Avey et al. [1] on black-capped chickadees that used similar stimulus types. These results are consistent with the previous study which also found no significant differences in expression following playback of calls produced by various heterospecific species and conspecifics [1]. Our results suggest that, similar to black-capped chickadees, IEG expression in zebra finch CMM and NCM is tied to the acoustic similarity of vocalizations and not the phylogenetic relatedness of the species producing the vocalizations. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Combined organizational and activational effects of short and long photoperiods on spatial and temporal memory in rats.

    PubMed

    MacDonald, Christopher J; Cheng, Ruey-Kuang; Williams, Christina L; Meck, Warren H

    2007-02-22

    The present study examined the effects of photoperiod on spatial and temporal memory in adult Sprague-Dawley rats that were conceived and reared in different day lengths, i.e., short day (SD-8:16 light/dark) and long day (LD-16:8 light/dark). Both male and female LD rats demonstrated increased spatial memory capacity as evidenced by a lower number of choices to criterion in a 12-arm radial maze task relative to the performance of SD rats. SD rats also demonstrated a distortion in the content of temporal memory as evidenced by a proportional rightward shift in the 20 and 60 s temporal criteria trained using the peak-interval procedure that is consistent with reduced cholinergic function. The conclusion is that both spatial and temporal memory are sensitive to photoperiod variation in laboratory rats in a manner similar to that previously observed for reproductive behaviour.

  3. Abscisic Acid and the Photoperiodic Induction of Dormancy in Salix viminalis L 1

    PubMed Central

    Alvim, Ronald; Saunders, Peter F.; Barros, Raimundo S.

    1979-01-01

    A series of growth room experiments was carried out aiming to establish the role of abscisic acid on dormancy of Salix viminalis L. The inhibitor content and abscisic acid levels of extracts from roots, sap, leaves, and apical tissues of willow were measured using biological assay and gas-liquid chromatography. No evidence was obtained that photoperiodically mediated dormancy is associated with changes in abscisic acid levels or β-inhibitor activity. PMID:16660810

  4. DNA metabarcoding of nestling feces reveals provisioning of aquatic prey and resource partitioning among Neotropical migratory songbirds in a riparian habitat.

    PubMed

    Trevelline, Brian K; Nuttle, Tim; Hoenig, Brandon D; Brouwer, Nathan L; Porter, Brady A; Latta, Steven C

    2018-05-01

    Riparian habitats are characterized by substantial flows of emergent aquatic insects that cross the stream-forest interface and provide an important source of prey for insectivorous birds. The increased availability of prey arising from aquatic subsidies attracts high densities of Neotropical migratory songbirds that are thought to exploit emergent aquatic insects as a nestling food resource; however, the prey preferences and diets of birds in these communities are only broadly understood. In this study, we utilized DNA metabarcoding to investigate the extent to which three syntopic species of migratory songbirds-Acadian Flycatcher, Louisiana Waterthrush, and Wood Thrush-breeding in Appalachian riparian habitats (Pennsylvania, USA) exploit and partition aquatic prey subsidies as a nestling food resource. Despite substantial differences in adult foraging strategies, nearly every nestling in this study consumed aquatic taxa, suggesting that aquatic subsidies are an important prey resource for Neotropical migrants nesting in riparian habitats. While our results revealed significant interspecific dietary niche divergence, the diets of Acadian Flycatcher and Wood Thrush nestlings were strikingly similar and exhibited significantly more overlap than expected. These results suggest that the dietary niches of Neotropical migrants with divergent foraging strategies may converge due to the opportunistic provisioning of non-limiting prey resources in riparian habitats. In addition to providing the first application of DNA metabarcoding to investigate diet in a community of Neotropical migrants, this study emphasizes the importance of aquatic subsidies in supporting breeding songbirds and improves our understanding of how anthropogenic disturbances to riparian habitats may negatively impact long-term avian conservation.

  5. The Origin of Time in the Songbird Motor Pathway

    NASA Astrophysics Data System (ADS)

    Long, Michael

    2010-03-01

    Many complex behaviors, like speech or music, have a hierarchical organization with structure on many timescales. How does the brain control the timing and ordering of behavioral sequences? Do different circuits control different timescales of the behavior? To begin answering these questions, we use temperature to manipulate the biophysical dynamics in different regions of the songbird forebrain involved in song production. We found that cooling premotor nucleus HVC (high vocal center) uniformly slows song speed by up to 40% while only slightly altering the acoustic structure, whereas cooling downstream motor nucleus RA (robust nucleus of the arcopallium) has no observable effect on song timing, despite a marked affect of RA spiking activity. To better understand the circuit mechanisms of precise premotor timing, we perform intracellular recordings in RA-projecting HVC neurons during singing. Our observations suggest highly ordered dynamics within HVC which are consistent with a synfire-like neuronal architecture.

  6. Do digestive contents confound body mass as a measure of relative condition in nestling songbirds?

    USGS Publications Warehouse

    Streby, Henry M.; Peterson, Sean M.; Lehman, Justin A.; Kramer, Gunnar R.; Vernasco, Ben J.; Andersen, David E.

    2014-01-01

    Relative nestling condition, typically measured as nestling mass or as an index including nestling mass, is commonly purported to correlate with fledgling songbird survival. However, most studies directly investigating fledgling survival have found no such relationship. We weighed feces and stomach contents of nestling golden-winged warblers (Vermivora chrysoptera) to investigate the potential contribution of variation in digestive contents to differences in nestling mass. We estimated that the mass of a seventh-day (near fledging) nestling golden-winged warbler varies by 0.65 g (approx. 9% of mean nestling mass) depending on the contents of the nestling's digestive system at the time of weighing, and that digestive contents are dissimilar among nestlings at any moment the brood is removed from the nest for weighing. Our conservative estimate of within-individual variation in digestive contents equals 72% and 24% of the mean within-brood and population-wide range in nestling mass, respectively. Based on our results, a substantive but typically unknown amount of the variation in body mass among nestlings is confounded by differences in digestive contents. We conclude that short-term variation in digestive contents likely precludes the use of body mass, and therefore any mass-dependent index, as a measure of relative nestling condition or as a predictor of survival in golden-winged warblers and likely in many other songbirds of similar size.

  7. Effects of temperature and photoperiod on lure display and glochidial release in a freshwater mussel

    Treesearch

    Andrew M. Gascho-Landis; Tyler L. Mosley; Wendell R. Haag; James A. Stoeckel

    2012-01-01

    Freshwater mussels use an array of strategies to transfer their parasitic larvae (glochidia) to fish hosts. We examined the effects of temperature, photoperiod, and female gravidity on mantle lure display and conglutinate release by Ligumia subrostrata (Say, 1831) in 2 laboratory experiments. In the 1st experiment, we examined the use of these strategies in 4...

  8. Effects of temperature and photoperiod on daily activity rhythms of Lutzomyia longipalpis (Diptera: Psychodidae).

    PubMed

    Rivas, Gustavo B S; de Souza, Nataly Araujo; Peixoto, Alexandre A; Bruno, Rafaela V

    2014-06-19

    Insect vectors have been established as models in Chronobiology for many decades, and recent studies have demonstrated a close relationship between the circadian clock machinery, daily rhythms of activity and vectorial capacity. Lutzomyia longipalpis, the primary vector of Leishmania (Leishmania) infantum in the New World, is reported to have crepuscular/nocturnal activity in the wild. However, most of these studies applied hourly CDC trap captures, which is a good indicative of L. longipalpis behaviour, but has limited accuracy due to the inability to record the daily activity of a single insect during consecutive days. In addition, very little is known about the activity pattern of L. longipalpis under seasonal variations of average temperature and day length in controlled laboratory conditions. We recorded the locomotor activity of L. longipalpis males under different artificial regimes of temperature and photoperiod. First, in order to test the effects of temperature on the activity, sandflies were submitted to regimes of light/dark cycles similar to the equinox photoperiod (LD 12:12) combined with different constant temperatures (20°C, 25°C and 30°C). In addition, we recorded sandfly locomotor activity under a mild constant temperature (25°C with different day length regimes: 8 hours, 12 hours and 16 hours). L. longipalpis exhibited more activity at night, initiating dusk-related activity (onset time) at higher rather than lower temperatures. In parallel, changes of photoperiod affected anticipation as well as all the patterns of activity (onset, peak and offset time). However, under LD 16:08, sandflies presented the earliest values of maximum peak and offset times, contrary to other regimes. Herein, we showed that light and temperature modulate L. longipalpis behaviour under controlled laboratory conditions, suggesting that sandflies might use environmental information to sustain their crepuscular/nocturnal activity, as well as other important aspects as

  9. Effects of temperature and photoperiod on daily activity rhythms of Lutzomyia longipalpis (Diptera: Psychodidae)

    PubMed Central

    2014-01-01

    Background Insect vectors have been established as models in Chronobiology for many decades, and recent studies have demonstrated a close relationship between the circadian clock machinery, daily rhythms of activity and vectorial capacity. Lutzomyia longipalpis, the primary vector of Leishmania (Leishmania) infantum in the New World, is reported to have crepuscular/nocturnal activity in the wild. However, most of these studies applied hourly CDC trap captures, which is a good indicative of L. longipalpis behaviour, but has limited accuracy due to the inability to record the daily activity of a single insect during consecutive days. In addition, very little is known about the activity pattern of L. longipalpis under seasonal variations of average temperature and day length in controlled laboratory conditions. Methods We recorded the locomotor activity of L. longipalpis males under different artificial regimes of temperature and photoperiod. First, in order to test the effects of temperature on the activity, sandflies were submitted to regimes of light/dark cycles similar to the equinox photoperiod (LD 12:12) combined with different constant temperatures (20°C, 25°C and 30°C). In addition, we recorded sandfly locomotor activity under a mild constant temperature (25°C with different day length regimes: 8 hours, 12 hours and 16 hours). Results L. longipalpis exhibited more activity at night, initiating dusk-related activity (onset time) at higher rather than lower temperatures. In parallel, changes of photoperiod affected anticipation as well as all the patterns of activity (onset, peak and offset time). However, under LD 16:08, sandflies presented the earliest values of maximum peak and offset times, contrary to other regimes. Conclusions Herein, we showed that light and temperature modulate L. longipalpis behaviour under controlled laboratory conditions, suggesting that sandflies might use environmental information to sustain their crepuscular

  10. The effect of photoperiod on life history and blood-feeding activity in Aedes albopictus and Aedes aegypti (Diptera: Culicidae).

    PubMed

    Costanzo, K S; Schelble, S; Jerz, K; Keenan, M

    2015-06-01

    Several studies have examined how climatic variables such as temperature and precipitation may affect life history traits in mosquitoes that are important to disease transmission. Despite its importance as a seasonal cue in nature, studies investigating the influence of photoperiod on such traits are relatively few. This study aims to investigate how photoperiod alters life history traits, survival, and blood-feeding activity in Aedes albopictus (Skuse) and Aedes aegypti (Linnaeus). We performed three experiments that tested the effects of day length on female survival, development time, adult size, fecundity, adult life span, and propensity to blood feed in Ae. albopictus and Ae. aegypti. Each experiment had three photoperiod treatments: 1) short-day (10L:14D), 2) control (12L:12D), and 3) long-day (14L:10D). Aedes albopictus adult females were consistently larger in size when reared in short-day conditions. Aedes aegypti adult females from short-day treatments lived longer and were more likely to take a blood meal compared to other treatments. We discuss how species-specific responses may reflect alternative strategies evolved to increase survival during unfavorable conditions. We review the potential impacts of these responses on seasonal transmission patterns, such as potentially increasing vectorial capacity of Ae. aegypti during periods of shorter day lengths. © 2015 The Society for Vector Ecology.

  11. Organophosphate pesticide method development and presence of chlorpyrifos in the feet of nearctic-neotropical migratory songbirds from Canada that over-winter in Central America agricultural areas.

    PubMed

    Alharbi, Hattan A; Letcher, Robert J; Mineau, Pierre; Chen, Da; Chu, Shaogang

    2016-02-01

    Recent modeling analysis suggests that numerous birds may be at risk of acute poisoning in insecticide-treated fields. Although the majority of avian field studies on pesticides have focused on treated seed, granule, insect or vegetation (oral exposure) ingestion, dermal exposure is an important exposure route when birds come into contact with deposited pesticides on foliage and other surfaces. Some nearctic-neotropical migratory songbirds are likely exposed to pesticides on their non-breeding habitats and include treated crops, plantations or farmlands. In the present study, we developed a method for four environmentally-relevant organophosphate (OP) pesticides (fenthion, fenamiphos, chlorpyrifos and diazinon) in the feet of migratory songbirds (i.e. Common yellowthroat, Gray catbird, Indigo bunting, America redstart, Northern waterthrush, Northern parula, and an additional 12 species of warblers). A total of 190 specimens of the 18 species of songbirds were sampled from available window-killed birds (spring of 2007 and 2011) in downtown Toronto, Canada. The species that were available most likely over-wintered in Mexican/Central American crops such as citrus, coffee and cacao. The feet of the dead birds were sampled and where OP foot exposure likely occurred during over-wintering foraging on pesticide-treated crops. Chlorpyrifos was the only measurable OP (pg mg feet weight(-1)) and in the 2011-collected feet of Black throated blue warbler (0.5), Tennessee warbler (1.0), Northern parula (1.2), Northern waterthrush (0.6), Common yellowthroat (1.0) and the Blue winged warbler (0.9). Dermal contact with OP pesticides during over-wintering in agricultural areas resulted in low levels of chlorpyrifos and long time retention on the feet of a subset of songbirds. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  12. HvLUX1 is a candidate gene underlying the early maturity 10 locus in barley: phylogeny, diversity, and interactions with the circadian clock and photoperiodic pathways

    PubMed Central

    Campoli, Chiara; Pankin, Artem; Drosse, Benedikt; Casao, Cristina M; Davis, Seth J; von Korff, Maria

    2013-01-01

    Photoperiodic flowering is a major factor determining crop performance and is controlled by interactions between environmental signals and the circadian clock. We proposed Hvlux1, an ortholog of the Arabidopsis circadian gene LUX ARRHYTHMO, as a candidate underlying the early maturity 10 (eam10) locus in barley (Hordeum vulgare L.). The link between eam10 and Hvlux1 was discovered using high-throughput sequencing of enriched libraries and segregation analysis. We conducted functional, phylogenetic, and diversity studies of eam10 and HvLUX1 to understand the genetic control of photoperiod response in barley and to characterize the evolution of LUX-like genes within barley and across monocots and eudicots. We demonstrate that eam10 causes circadian defects and interacts with the photoperiod response gene Ppd-H1 to accelerate flowering under long and short days. The results of phylogenetic and diversity analyses indicate that HvLUX1 was under purifying selection, duplicated at the base of the grass clade, and diverged independently of LUX-like genes in other plant lineages. Taken together, these findings contribute to improved understanding of the barley circadian clock, its interaction with the photoperiod pathway, and evolution of circadian systems in barley and across monocots and eudicots. PMID:23731278

  13. Morphological basis for the evolution of acoustic diversity in oscine songbirds

    PubMed Central

    Riede, Tobias; Goller, Franz

    2014-01-01

    Acoustic properties of vocalizations arise through the interplay of neural control with the morphology and biomechanics of the sound generating organ, but in songbirds it is assumed that the main driver of acoustic diversity is variation in telencephalic motor control. Here we show, however, that variation in the composition of the vibrating tissues, the labia, underlies diversity in one acoustic parameter, fundamental frequency (F0) range. Lateral asymmetry and arrangement of fibrous proteins in the labia into distinct layers is correlated with expanded F0 range of species. The composition of the vibrating tissues thus represents an important morphological foundation for the generation of a broad F0 range, indicating that morphological specialization lays the foundation for the evolution of complex acoustic repertoires. PMID:24500163

  14. Morphological basis for the evolution of acoustic diversity in oscine songbirds.

    PubMed

    Riede, Tobias; Goller, Franz

    2014-03-22

    Acoustic properties of vocalizations arise through the interplay of neural control with the morphology and biomechanics of the sound generating organ, but in songbirds it is assumed that the main driver of acoustic diversity is variation in telencephalic motor control. Here we show, however, that variation in the composition of the vibrating tissues, the labia, underlies diversity in one acoustic parameter, fundamental frequency (F0) range. Lateral asymmetry and arrangement of fibrous proteins in the labia into distinct layers is correlated with expanded F0 range of species. The composition of the vibrating tissues thus represents an important morphological foundation for the generation of a broad F0 range, indicating that morphological specialization lays the foundation for the evolution of complex acoustic repertoires.

  15. Biocapture of CO2 by Different Microalgal-Based Technologies for Biogas Upgrading and Simultaneous Biogas Slurry Purification under Various Light Intensities and Photoperiods

    PubMed Central

    Guo, Pengfei; Zhang, Yuejin; Zhao, Yongjun

    2018-01-01

    Co-cultivation of microalgae and microbes for pollutant removal from sewage is considered as an effective wastewater treatment method. The aim of this study is to screen the optimal photoperiod, light intensity and microalgae co-cultivation method for simultaneously removing nutrients in biogas slurry and capturing CO2 in biogas. The microalgae–fungi pellets are deemed to be a viable option because of their high specific growth rate and nutrient and CO2 removal efficiency under the photoperiod of 14 h light:10 h dark. The order of both the biogas slurry purification and biogas upgrading is ranked the same, that is Chlorella vulgaris–Ganoderma lucidum > Chlorella vulgaris–activated sludge > Chlorella vulgaris under different light intensities. For all cultivation methods, the moderate light intensity of 450 μmol m−2 s−1 is regarded as the best choice. This research revealed that the control of photoperiod and light intensity can promote the biological treatment process of biogas slurry purification and biogas upgrading using microalgal-based technology. PMID:29543784

  16. Declining brown-headed cowbird (Molothrus ater) populations are associated with landscape-specific reductions in brood parasitism and increases in songbird productivity

    Treesearch

    W. Andrew Cox; Frank R., III Thompson; Brian Root; John Faaborg; Csaba Moskat

    2012-01-01

    Many songbird species have experienced significant population declines, partly because of brood parasitism by the Brown-headed Cowbird (Molothrus ater), which is positively associated with increasing landscape forest cover in the midwestern United States. However, cowbirds are also experiencing long-term population declines, which should reduce...

  17. Immediate early gene expression following exposure to acoustic and visual components of courtship in zebra finches.

    PubMed

    Avey, Marc T; Phillmore, Leslie S; MacDougall-Shackleton, Scott A

    2005-12-07

    Sensory driven immediate early gene expression (IEG) has been a key tool to explore auditory perceptual areas in the avian brain. Most work on IEG expression in songbirds such as zebra finches has focused on playback of acoustic stimuli and its effect on auditory processing areas such as caudal medial mesopallium (CMM) caudal medial nidopallium (NCM). However, in a natural setting, the courtship displays of songbirds (including zebra finches) include visual as well as acoustic components. To determine whether the visual stimulus of a courting male modifies song-induced expression of the IEG ZENK in the auditory forebrain we exposed male and female zebra finches to acoustic (song) and visual (dancing) components of courtship. Birds were played digital movies with either combined audio and video, audio only, video only, or neither audio nor video (control). We found significantly increased levels of Zenk response in the auditory region CMM in the two treatment groups exposed to acoustic stimuli compared to the control group. The video only group had an intermediate response, suggesting potential effect of visual input on activity in these auditory brain regions. Finally, we unexpectedly found a lateralization of Zenk response that was independent of sex, brain region, or treatment condition, such that Zenk immunoreactivity was consistently higher in the left hemisphere than in the right and the majority of individual birds were left-hemisphere dominant.

  18. Mechanistic understanding of the effects of natural gas development on sagebrush-obligate songbird nest predation rates

    NASA Astrophysics Data System (ADS)

    Hethcoat, Matthew G.

    Natural gas development has rapidly increased within sagebrush ( Artemisia spp.) dominated landscapes of the Intermountain West. Prior research in the Upper Green River Basin, Wyoming demonstrated increased nest predation of sagebrush-obligate songbirds with higher densities of natural gas wells. To better understand the mechanisms underlying this pattern, I assessed this commonly used index of oil and gas development intensity (well density) for estimating habitat transformation and predicting nest survival for songbirds breeding in energy fields during 2008- 2009 and 2011-2012. We calculated landscape metrics (habitat loss, amount of edge, patch shape complexity, and mean patch size) to identify the aspect of landscape transformation most captured by well density. Well density was most positively associated with the amount of habitat loss within 1 square kilometer. Daily nest survival was relatively invariant with respect to well density for all three species. In contrast, nest survival rates of all three species consistently decreased with increased surrounding habitat loss due to energy development. Thus, although well density and habitat loss were strongly correlated, at times they provided contrasting estimates of nest survival probability. Additionally, we tested the hypothesis that surrounding habitat loss influenced local nest predation rates via increased predator activity. During 2011- 2012, we surveyed predators and monitored songbird nests at twelve sites in western Wyoming. Nine species, representing four mammalian and three avian families, were video-recorded depredating eggs and nestlings. Approximately 75% of depredation events were caused by rodents. While chipmunk (Tamias minimus) detections were negatively associated with increased habitat loss, mice (Peromyscus maniculatus and Reithrodontomys megalotis) and ground squirrels (Ictidomys tridecemlineatus and Urocitellus armatus) increased with greater surrounding habitat loss. Consistent with our

  19. Determining the sources of calcium for migratory songbirds using stable strontium isotopes.

    PubMed

    Blum, Joel D; Taliaferro, E Hank; Holmes, Richard T

    2001-02-01

    We investigated natural variations in the stable isotopic composition of strontium (a surrogate for calcium) in the bones of a single species of breeding migratory songbird, as well as in their eggshells, egg contents, and food sources. We use this information to determine the sources of calcium to these migratory songbirds and their offspring. Samples were collected from two locations in the northeastern USA (Hubbard Brook, NH, and Downer Forest, VT.) that differed in soil geochemistry. The mean 87 Sr/ 86 Sr ratios of food items (caterpillars and snails), eggshells, and egg contents were indistinguishable within each site, but significantly different between the two sites. Mean 87 Sr/ 86 Sr ratios for the bones of adult females were significantly different between the two sites, but values were significantly lower than those of food items and eggshells at each site. Two of four adult individuals studied at each site had 87 Sr/ 86 Sr ratios lower than the entire range of values for local food sources. Mixing calculations indicate that up to 60% of skeletal strontium and calcium was derived from foods consumed in the winter grounds where lower 87 Sr/ 86 Sr ratios predominate. At each study site, the 87 Sr/ 86 Sr ratio of eggshells differed significantly between clutches, but the mean clutch 87 Sr/ 86 Sr ratios were unrelated to the skeletal 87 Sr/ 86 Sr ratio of the laying adult. These findings suggest that strontium (and hence calcium) for eggshell production in this species is derived predominantly from local food sources in breeding areas. Thus, reductions in available calcium in northern temperate ecosystems due to the influences of acid deposition could be potentially harmful to this and other species of migratory bird.

  20. Audience drives male songbird response to partner's voice.

    PubMed

    Vignal, Clémentine; Mathevon, Nicolas; Mottin, Stéphane

    2004-07-22

    According to the social intelligence hypothesis, social context represents an important force driving the selection of animal cognitive abilities such as the capacity to estimate the nature of the social relationships between other individuals. Despite this importance, the influence of this force has been assessed only in primates and never in other animals showing social interactions. In this way, avian communication generally takes place in a network of signallers and receivers, which represents an audience altering individual signalling behaviours. Indeed, vocal amplitude and repertoire are known to be socially regulated and the attitude towards the opposite sex may change depending on the audience. This 'audience effect' provides support for the reality of social awareness in some bird species. However no evidence has yet been found to suggest that birds are able to estimate the characteristics of the social relationships between group-mates. Here we show that the male of a gregarious songbird species--the zebra finch (Taeniopygia guttata)--pays attention to the mating status of conspecific pairs, and uses this information to control its behaviour towards its female partner.

  1. Photoperiod and temperature constraints on the relationship between the photochemical reflectance index and the light use efficiency of photosynthesis in Pinus strobus.

    PubMed

    Fréchette, Emmanuelle; Chang, Christine Yao-Yun; Ensminger, Ingo

    2016-03-01

    The photochemical reflectance index (PRI) is a proxy for the activity of the photoprotective xanthophyll cycle and photosynthetic light use efficiency (LUE) in plants. Evergreen conifers downregulate photosynthesis in autumn in response to low temperature and shorter photoperiod, and the dynamic xanthophyll cycle-mediated non-photochemical quenching (NPQ) is replaced by sustained NPQ. We hypothesized that this shift in xanthophyll cycle-dependent energy partitioning during the autumn is the cause for variations in the PRI-LUE relationship. In order to test our hypothesis, we characterized energy partitioning and pigment composition during a simulated summer-autumn transition in a conifer and assessed the effects of temperature and photoperiod on the PRI-LUE relationship. We measured gas exchange, chlorophyll fluorescence and leaf reflectance during the photosynthetic downregulation in Pinus strobus L. seedlings exposed to low temperature/short photoperiod or elevated temperature/short photoperiod conditions. Shifts in energy partitioning during simulated autumn were observed when the pools of chlorophylls decreased and pools of photoprotective carotenoids increased. On a seasonal timescale, PRI was controlled by carotenoid pool sizes rather than xanthophyll cycle dynamics. Photochemical reflectance index variation under cold autumn conditions mainly reflected long-term pigment pool adjustments associated with sustained NPQ, which impaired the PRI-LUE relationship. Exposure to warm autumn conditions prevented the induction of sustained NPQ but still impaired the PRI-LUE relationship. We therefore conclude that alternative zeaxanthin-independent NPQ mechanisms, which remain undetected by the PRI, are present under both cold and warm autumn conditions, contributing to the discrepancy in the PRI-LUE relationship during autumn. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Management of early-successional communities in central hardwood forests: with special emphasis on the ecology and management of oaks, ruffed grouse, and forest songbirds.

    Treesearch

    Frank R. III Thompson; Daniel R. Dessecker

    1997-01-01

    Describes the history, ecology, and silviculture of central hardwood forests and the status and ecology of early-successional forest songbirds and ruffed grouse. Concludes with management guidelines for early-successional communities in central hardwood forests.

  3. Effects of sex and seasonality on the song control system and FoxP2 protein expression in black-capped chickadees (Poecile atricapillus).

    PubMed

    Phillmore, Leslie S; MacGillivray, Heather L; Wilson, K Ryan; Martin, Stephanie

    2015-02-01

    Plasticity in behavior is mirrored by corresponding plasticity in the brain in many songbird species. In some species, song system nuclei (Phillmore et al. [2006]: J Neurobiol 66:1002-1010) are larger in birds in breeding condition than birds in nonbreeding condition, possibly due to increased vocal output in spring. FOXP2, a transcription factor associated with language expression and comprehension in humans and song learning in songbirds, also shows plasticity. FoxP2 expression in songbird Area X, a region important for sensorimotor integration, is related to developmental and adult vocal plasticity (Teramitsu et al. [2010]: J Neurosci 24:3152-3163, Chen et al. [2013], J Exp Biol 216:3682-3692). In this study, we examined whether sex and breeding condition affects both song control system volume (HVC, X) and FoxP2 protein expression in black-capped chickadees (Poecile atricapillus). HVC volume was larger in males in breeding condition than males in nonbreeding condition, but there were no sex differences. In contrast, Area X volume was larger in males than females, regardless of breeding condition, likely reflecting that male and female chickadees produce learned chick-a-dee calls year round, but output of the learned song increases in breeding males. FoxP2 protein levels did not differ between sexes or breeding condition when calculated as a ratio of labeled cells in Area X to labeled cells in the surrounding striato-pallium, however, absolute density of FoxP2 in both regions was higher in males than in females. This may indicate that chickadees maintain a level of FoxP2 necessary for plasticity year-round, but males have greater potential for plasticity compared to females. © 2014 Wiley Periodicals, Inc.

  4. Trigeminal and telencephalic projections to jaw and other upper vocal tract premotor neurons in songbirds: sensorimotor circuitry for beak movements during singing.

    PubMed

    Wild, J M; Krützfeldt, N E O

    2012-02-15

    During singing in songbirds, the extent of beak opening, like the extent of mouth opening in human singers, is partially correlated with the fundamental frequency of the sounds emitted. Since song in songbirds is under the control of "the song system" (a collection of interconnected forebrain nuclei dedicated to the learning and production of song), it might be expected that beak movements during singing would also be controlled by this system. However, direct neural connections between the telencephalic output of the song system and beak muscle motor neurons in the brainstem are conspicuous by their absence, leaving unresolved the question of how beak movements are affected during singing. By using standard tract tracing methods, we sought to answer this question by defining beak premotor neurons and examining their afferent projections. In the caudal medulla, jaw premotor cell bodies were located adjacent to the terminal field of the output of the song system, into which many premotor neurons extended their dendrites. The premotor neurons also received a novel input from the trigeminal ganglion and an overlapping input from a lateral arcopallial component of a trigeminal sensorimotor circuit that traverses the forebrain. The ganglionic input in songbirds, which is not present in doves and pigeons that vocalize with a closed beak, may modulate the activity of beak premotor neurons in concert with the output of the song system. These inputs to jaw premotor neurons could, together, affect beak movements as a means of modulating filter properties of the upper vocal tract during singing. Copyright © 2011 Wiley-Liss, Inc.

  5. Trigeminal and Telencephalic Projections to Jaw and Other Upper Vocal Tract Premotor Neurons in Songbirds: Sensorimotor Circuitry for Beak Movements During Singing

    PubMed Central

    Wild, J.M.; Krützfeldt, N.E.O.

    2014-01-01

    During singing in songbirds, the extent of beak opening, like the extent of mouth opening in human singers, is partially correlated with the fundamental frequency of the sounds emitted. Since song in songbirds is under the control of “the song system” (a collection of interconnected forebrain nuclei dedicated to the learning and production of song), it might be expected that beak movements during singing would also be controlled by this system. However, direct neural connections between the telencephalic output of the song system and beak muscle motor neurons in the brainstem are conspicuous by their absence, leaving unresolved the question of how beak movements are affected during singing. By using standard tract tracing methods, we sought to answer this question by defining beak premotor neurons and examining their afferent projections. In the caudal medulla, jaw premotor cell bodies were located adjacent to the terminal field of the output of the song system, into which many premotor neurons extended their dendrites. The premotor neurons also received a novel input from the trigeminal ganglion and an overlapping input from a lateral arcopallial component of a trigeminal sensorimotor circuit that traverses the forebrain. The ganglionic input in songbirds, which is not present in doves and pigeons that vocalize with a closed beak, may modulate the activity of beak premotor neurons in concert with the output of the song system. These inputs to jaw premotor neurons could, together, affect beak movements as a means of modulating filter properties of the upper vocal tract during singing. PMID:21858818

  6. Temporal processing and adaptation in the songbird auditory forebrain.

    PubMed

    Nagel, Katherine I; Doupe, Allison J

    2006-09-21

    Songbird auditory neurons must encode the dynamics of natural sounds at many volumes. We investigated how neural coding depends on the distribution of stimulus intensities. Using reverse-correlation, we modeled responses to amplitude-modulated sounds as the output of a linear filter and a nonlinear gain function, then asked how filters and nonlinearities depend on the stimulus mean and variance. Filter shape depended strongly on mean amplitude (volume): at low mean, most neurons integrated sound over many milliseconds, while at high mean, neurons responded more to local changes in amplitude. Increasing the variance (contrast) of amplitude modulations had less effect on filter shape but decreased the gain of firing in most cells. Both filter and gain changes occurred rapidly after a change in statistics, suggesting that they represent nonlinearities in processing. These changes may permit neurons to signal effectively over a wider dynamic range and are reminiscent of findings in other sensory systems.

  7. Genetic and molecular characterization of photoperiod and thermo-sensitive male sterility in rice.

    PubMed

    Fan, Yourong; Zhang, Qifa

    2018-03-01

    A review on photoperiod and temperature-sensitive genic male sterility in rice. Male sterility in plants, facilitating the development of hybrid crops, has made great contribution to crop productivity worldwide. Environment-sensitive genic male sterility (EGMS), including photoperiod-sensitive genic male sterility (PGMS) and temperature-sensitive genic male sterility (TGMS), has provided a special class of germplasms for the breeding of "two-line" hybrids in several crops. In rice, the finding of the PGMS NK58S mutant in 1973 started the journey of research and breeding of two-line hybrids. Genetic and molecular characterization of these germplasms demonstrated diverse genes and molecular mechanisms of male sterility regulation. Two loci identified from NK58S, PMS1 and PMS3, both encode long noncoding RNAs. A major TGMS locus, TMS5, found in the TGMS line Annong S-1, encodes an RNase Z. A reverse PGMS mutant carbon starved anther encodes an R2R3 MYB transcription factor. Breeding efforts in the last three decades have resulted in hundreds of EGMS lines and two-line hybrids released to rice production, which have greatly elevated the yield potential and grain quality of rice varieties. The enhanced molecular understanding will offer new strategies for the development of EGMS lines thus further improving two-line hybrid breeding of rice as well as other crops.

  8. The influence of light intensity and photoperiod on duckweed biomass and starch accumulation for bioethanol production.

    PubMed

    Yin, Yehu; Yu, Changjiang; Yu, Li; Zhao, Jinshan; Sun, Changjiang; Ma, Yubin; Zhou, Gongke

    2015-01-01

    Duckweed has been considered as a valuable feedstock for bioethanol production due to its high biomass and starch production. To investigate the effects of light conditions on duckweed biomass and starch production, Lemna aequinoctialis 6000 was cultivated at different photoperiods (12:12, 16:8 and 24:0h) and light intensities (20, 50, 80, 110, 200 and 400μmolm(-2)s(-1)). The results showed that the duckweed biomass and starch production was increased with increasing light intensity and photoperiod except at 200 and 400μmolm(-2)s(-1). Considering the light cost, 110μmolm(-2)s(-1) was optimum light condition for starch accumulation with the highest maximum growth rate, biomass and starch production of 8.90gm(-2)day(-1), 233.25gm(-2) and 98.70gm(-2), respectively. Moreover, the results suggested that high light induction was a promising method for duckweed starch accumulation. This study provides optimized light conditions for future industrial large-scale duckweed cultivation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Shale gas development effects on the songbird community in a central Appalachian forest

    USGS Publications Warehouse

    Farwell, Laura S.; Wood, Petra; Sheehan, James; George, Gregory A.

    2016-01-01

    In the last decade, unconventional drilling for natural gas from the Marcellus-Utica shale has increased exponentially in the central Appalachians. This heavily forested region contains important breeding habitat for many neotropical migratory songbirds, including several species of conservation concern. Our goal was to examine effects of unconventional gas development on forest habitat and breeding songbirds at a predominantly forested site from 2008 to 2015. Construction of gas well pads and infrastructure (e.g., roads, pipelines) contributed to an overall 4.5% loss in forest cover at the site, a 12.4% loss in core forest, and a 51.7% increase in forest edge density. We evaluated the relationship between land-cover metrics and species richness within three avian guilds: forest-interior, early-successional, and synanthropic, in addition to abundances of 21 focal species. Land-cover impacts were evaluated at two spatial extents: a point-level within 100-m and 500-m buffers of each avian survey station, and a landscape-level across the study area (4326 ha). Although we observed variability in species-specific responses, we found distinct trends in long-term response among the three avian guilds. Forest-interior guild richness declined at all points across the site and at points impacted within 100 m by shale gas but did not change at unimpacted points. Early-successional and synanthropic guild richness increased at all points and at impacted points. Our results suggest that shale gas development has the potential to fragment regional forests and alter avian communities, and that efforts to minimize new development in core forests will reduce negative impacts to forest dependent species.

  10. Models of vocal learning in the songbird: Historical frameworks and the stabilizing critic.

    PubMed

    Nick, Teresa A

    2015-10-01

    Birdsong is a form of sensorimotor learning that involves a mirror-like system that activates with both song hearing and production. Early models of song learning, based on behavioral measures, identified key features of vocal plasticity, such as the requirements for memorization of a tutor song and auditory feedback during song practice. The concept of a comparator, which compares the memory of the tutor song to auditory feedback, featured prominently. Later models focused on linking anatomically-defined neural modules to behavioral concepts, such as the comparator. Exploiting the anatomical modularity of the songbird brain, localized lesions illuminated mechanisms of the neural song system. More recent models have integrated neuronal mechanisms identified in other systems with observations in songbirds. While these models explain multiple aspects of song learning, they must incorporate computational elements based on unknown biological mechanisms to bridge the motor-to-sensory delay and/or transform motor signals into the sensory domain. Here, I introduce the stabilizing critic hypothesis, which enables sensorimotor learning by (1) placing a purely sensory comparator afferent of the song system and (2) endowing song system disinhibitory interneuron networks with the capacity both to bridge the motor-sensory delay through prolonged bursting and to stabilize song segments selectively based on the comparator signal. These proposed networks stabilize an otherwise variable signal generated by both putative mirror neurons and a cortical-basal ganglia-thalamic loop. This stabilized signal then temporally converges with a matched premotor signal in the efferent song motor cortex, promoting spike-timing-dependent plasticity in the premotor circuitry and behavioral song learning. © 2014 Wiley Periodicals, Inc.

  11. Comparison of the life cycle and photoperiodic response between northern and southern populations of the terrestrial slug Lehmannia valentiana in Japan.

    PubMed

    Udaka, Hiroko; Numata, Hideharu

    2010-09-01

    The terrestrial slug Lehmannia valentiana was first recorded in Japan in the late 1950s and is now distributed throughout the country. Previous studies have revealed that in Osaka, southwestern Japan, L. valentiana reproduces from November to April. In the present study, in order to clarify the climatic adaptations of L. valentiana in Japan, we examined the life cycle of this slug in Sapporo, northern Japan. In the Sapporo population, the ratio of gonad weight to body weight reached a maximum in September. Most slugs had mature sperm from late August to April and large oocytes from September to April. Thus, the Sapporo population of L. valentiana commenced reproduction two months earlier than the Osaka population. We also examined the effect of various photoperiodic conditions on growth and reproductive maturation in both the Osaka and Sapporo populations. The effect of photoperiod on growth was different in the two populations. In both populations, however, reproductive maturation was induced by short days of photophase 14 h or less, and there was no obvious difference between the two populations, even though reproductive maturation in the wild commences in different seasons. This indicates the possibility that L. valentiana adapts to climatically different regions without changes in its critical daylength in photoperiodic response.

  12. Importation of exotic ticks and tick-borne spotted fever group rickettsiae into the United States by migrating songbirds.

    PubMed

    Mukherjee, Nabanita; Beati, Lorenza; Sellers, Michael; Burton, Laquita; Adamson, Steven; Robbins, Richard G; Moore, Frank; Karim, Shahid

    2014-03-01

    Birds are capable of carrying ticks and, consequently, tick-transmitted microorganisms over long distances and across geographical barriers such as oceans and deserts. Ticks are hosts for several species of spotted fever group rickettsiae (SFGR), which can be transmitted to vertebrates during blood meals. In this study, the prevalence of this group of rickettsiae was examined in ticks infesting migratory songbirds by using polymerase chain reaction (PCR). During the 2009 and 2010 spring migration season, 2064 northward-migrating passerine songbirds were examined for ticks at Johnson Bayou, Louisiana. A total of 91 ticks was removed from 35 individual songbirds for tick species identification and spotted fever group rickettsia detection. Ticks were identified as Haemaphysalis juxtakochi (n=38, 42%), Amblyomma longirostre (n=22, 24%), Amblyomma nodosum (n=17, 19%), Amblyomma calcaratum (n=11, 12%), Amblyomma maculatum (n=2, 2%), and Haemaphysalis leporispalustris (n=1, 1%) by comparing their 12S rDNA gene sequence to homologous sequences in GenBank. Most of the identified ticks were exotic species originating outside of the United States. The phylogenetic analysis of the 71 ompA gene sequences of the rickettsial strains detected in the ticks revealed the occurrence of 6 distinct rickettsial genotypes. Two genotypes (corresponding to a total of 28 samples) were included in the Candidatus Rickettsia amblyommii clade (less than 1% divergence), 2 of them (corresponding to a total of 14 samples) clustered with Rickettsia sp. "Argentina" with less than 0.2% sequence divergence, and 2 of them (corresponding to a total of 27 samples), although closely related to the R. parkeri-R. africae lineage (2.50-3.41% divergence), exhibited sufficient genetic divergence from its members to possibly constitute a new rickettsial genotype. Overall, there does not seem to be a specific relationship between exotic tick species, the rickettsiae they harbor, or the reservoir competence of the

  13. Induction and inhibition of diapause by the same photoperiod: experimental evidence for a "double circadian oscillator clock".

    PubMed

    Spieth, Hubert R; Xue, Fangsen; Strau, Katharina

    2004-12-01

    On the southern Iberian Peninsula, the seasonal life history of the large white butterfly, Pieris brassicae, comprises 2 different photoperiodically induced developmental arrests: a hibernation diapause at photophases < 11 h and an estivation diapause at photophases > 14 h. At intermediate photophases (12 h to 13 h), the butterfly responds with a nondiapause. Combined with the experimental setup to determine photosensitivity in insects, the different photoperiodic responses at long-, intermediate-, and short-night conditions were examined to gain more insight into the time measurement mechanism in P. brassicae. The study reveals evidence for a "double circadian oscillator clock" mechanism that is based on 2 submechanisms, a "short-night determining system" and a separate "long-night determining system." This conclusion was drawn from the facts that an LD 9:15 long-night induces a hibernation diapause but inhibits an estivation diapause and, conversely, that an LD 16:8 short-night inhibits a hibernation diapause but induces an estivation diapause. This opposite effect of the same photoperiod supports the argument for the existence of 2 independent targets for light-dark cycles, interpreted as 2 antagonistic time measurement systems. The existence and independence of 2 systems was further shown by differences in long-night versus short-night responses regarding photosensitivity, temperature dependence, and heritable factors. The long-night measurement system is most effective in the 5th larval stage, is highly affected by temperature, and is easy to manipulate by selective inbreeding. The short-night measurement system is most effective in the 4th larval stage, is largely temperature compensated, and is not affected by experimental manipulation of the longnight measurement system.

  14. CONTRASTING HABITAT ASSOCIATIONS OF SAGEBRUSH-STEPPE SONGBIRDS IN THE INTERMOUNTAIN WEST

    PubMed Central

    MILLER, ROBERT A.; BOND, LAURA; MIGAS, PATRICK N.; CARLISLE, JAY D.; KALTENECKER, GREGORY S.

    2017-01-01

    Sagebrush (Artemisia spp.) steppe is one of North America’s most imperiled ecosystems, as the result of many factors including grazing, development, fire, and invasion of exotic plants. Threats to sagebrush steppe are expected to increase because of climate change and further human development. Many songbirds use sagebrush steppe opportunistically, but a few obligate species are dependent on it. To quantify the habitat associations of three sagebrush obligates, the Sage Thrasher (Oreoscoptes montanus), Sagebrush Sparrow (Artemisiospiza nevadensis), and Brewer’s Sparrow (Spizella breweri), and nine other songbird species that use this habitat, we surveyed across a broad region of Idaho. At each of 104 sites, we selected three plots, one each in relatively poor, moderate, and good condition, defined qualitatively by the cover of native shrubs. We quantified bird abundance by point counts, described the habitat at these points by a line-intercept method, and at each plot calculated the fraction of a circle (radius 1 km) covered in shrubs or grassland. We compared two-scale occupancy models based on these data by the information-theoretic approach. According to the models, our qualitative assessment of habitat condition within a site distinguished birds’ use of relatively good habitat from their use of poor habitats only, not from those in moderate condition. Thus the sagebrush-obligate species may tolerate some local habitat degradation, at least up to some unidentified threshold. Occurrence of all three sagebrush obligates correlated well with one or more characteristics of sagebrush such as its cover, height, or heterogeneity in height. They differed in the Sage Thrasher being most sensitive to sagebrush cover, the Sagebrush Sparrow being found more often at lower elevations, and the Brewer’s Sparrow being less sensitive to ground cover. The nine other species evaluated were less or negatively associated with attributes of sagebrush. On the basis of these

  15. GmFT2a, a soybean homolog of FLOWERING LOCUS T, is involved in flowering transition and maintenance.

    PubMed

    Sun, Hongbo; Jia, Zhen; Cao, Dong; Jiang, Bingjun; Wu, Cunxiang; Hou, Wensheng; Liu, Yike; Fei, Zhihong; Zhao, Dazhong; Han, Tianfu

    2011-01-01

    Flowering reversion can be induced in soybean (Glycine max L. Merr.), a typical short-day (SD) dicot, by switching from SD to long-day (LD) photoperiods. This process may involve florigen, putatively encoded by FLOWERING LOCUS T (FT) in Arabidopsis thaliana. However, little is known about the potential function of soybean FT homologs in flowering reversion. A photoperiod-responsive FT homologue GmFT (renamed as GmFT2a hereafter) was cloned from the photoperiod-sensitive cultivar Zigongdongdou. GmFT2a gene expression under different photoperiods was analyzed by real-time quantitative PCR. In situ hybridization showed direct evidence for its expression during flowering-related processes. GmFT2a was shown to promote flowering using transgenic studies in Arabidopsis and soybean. The effects of photoperiod and temperature on GmFT2a expression were also analyzed in two cultivars with different photoperiod-sensitivities. GmFT2a expression is regulated by photoperiod. Analyses of GmFT2a transcripts revealed a strong correlation between GmFT2a expression and flowering maintenance. GmFT2a transcripts were observed continuously within the vascular tissue up to the shoot apex during flowering. By contrast, transcripts decreased to undetectable levels during flowering reversion. In grafting experiments, the early-flowering, photoperiod-insensitive stock Heihe27 promotes the appearance of GmFT2a transcripts in the shoot apex of scion Zigongdongdou under noninductive LD conditions. The photothermal effects of GmFT2a expression diversity in cultivars with different photoperiod-sensitivities and a hypothesis is proposed. GmFT2a expression is associated with flowering induction and maintenance. Therefore, GmFT2a is a potential target gene for soybean breeding, with the aim of increasing geographic adaptation of this crop.

  16. Relationships among chilling hours, photoperiod, calendar date, cold hardiness, seed source, and storage of Douglas-fir seedlings

    Treesearch

    Diane L. Haase; Nabil Khadduri; Euan Mason; Kas Dumroese

    2016-01-01

    Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) seedlings from three nurseries in the Pacific Northwest United States were lifted on five dates from mid-October through mid-December 2006. Each nursery provided seedlings from a low- and a high-elevation seed lot. Photoperiod and accumulated chilling hours (calculated using two methods) were evaluated...

  17. Growth and splitting of neural sequences in songbird vocal development

    PubMed Central

    Okubo, Tatsuo S.; Mackevicius, Emily L.; Payne, Hannah L.; Lynch, Galen F.; Fee, Michale S.

    2015-01-01

    Neural sequences are a fundamental feature of brain dynamics underlying diverse behaviors, but the mechanisms by which they develop during learning remain unknown. Songbirds learn vocalizations composed of syllables; in adult birds, each syllable is produced by a different sequence of action potential bursts in the premotor cortical area HVC. Here we carried out recordings of large populations of HVC neurons in singing juvenile birds throughout learning to examine the emergence of neural sequences. Early in vocal development, HVC neurons begin producing rhythmic bursts, temporally locked to a ‘prototype’ syllable. Different neurons are active at different latencies relative to syllable onset to form a continuous sequence. Through development, as new syllables emerge from the prototype syllable, initially highly overlapping burst sequences become increasingly distinct. We propose a mechanistic model in which multiple neural sequences can emerge from the growth and splitting of a common precursor sequence. PMID:26618871

  18. Using Citizen Science Data to Model the Distributions of Common Songbirds of Turkey Under Different Global Climatic Change Scenarios

    PubMed Central

    Abolafya, Moris; Onmuş, Ortaç; Şekercioğlu, Çağan H.; Bilgin, Raşit

    2013-01-01

    In this study, we evaluated the potential impact of climate change on the distributions of Turkey’s songbirds in the 21st century by modelling future distributions of 20 resident and nine migratory species under two global climate change scenarios. We combined verified data from an ornithological citizen science initiative (www.kusbank.org) with maximum entropy modeling and eight bioclimatic variables to estimate species distributions and projections for future time periods. Model predictions for resident and migratory species showed high variability, with some species projected to lose and others projected to gain suitable habitat. Our study helps improve the understanding of the current and potential future distributions of Turkey’s songbirds and their responses to climate change, highlights effective strategies to maximize avian conservation efforts in the study region, and provides a model for using citizen science data for biodiversity research in a large developing country with few professional field biologists. Our results demonstrate that climate change will not affect every species equally in Turkey. Expected range reductions in some breeding species will increase the risk of local extinction, whereas others are likely to expand their ranges. PMID:23844151

  19. Using citizen science data to model the distributions of common songbirds of Turkey under different global climatic change scenarios.

    PubMed

    Abolafya, Moris; Onmuş, Ortaç; Şekercioğlu, Çağan H; Bilgin, Raşit

    2013-01-01

    In this study, we evaluated the potential impact of climate change on the distributions of Turkey's songbirds in the 21st century by modelling future distributions of 20 resident and nine migratory species under two global climate change scenarios. We combined verified data from an ornithological citizen science initiative (www.kusbank.org) with maximum entropy modeling and eight bioclimatic variables to estimate species distributions and projections for future time periods. Model predictions for resident and migratory species showed high variability, with some species projected to lose and others projected to gain suitable habitat. Our study helps improve the understanding of the current and potential future distributions of Turkey's songbirds and their responses to climate change, highlights effective strategies to maximize avian conservation efforts in the study region, and provides a model for using citizen science data for biodiversity research in a large developing country with few professional field biologists. Our results demonstrate that climate change will not affect every species equally in Turkey. Expected range reductions in some breeding species will increase the risk of local extinction, whereas others are likely to expand their ranges.

  20. Photoperiod: Its importance as an impeller of pineal and seasonal reproductive rhythms

    NASA Astrophysics Data System (ADS)

    Reiter, R. J.

    1980-03-01

    A number of long day breeding rodents depend on seasonal changes in photoperiodic length to synchronize their breeding seasons with the appropriate time of the year. These relationships are particularly conspicuous in the Syrian hamster where day length is vitally important in determining periods of sexual activity and inactivity. The organ in the body whose activity is most closely attuned to the photoperiodic environment is the pineal gland. During periods of darkness the biochemical and secretory activity of the pineal is enhanced with the resultant production of antigonadotrophic principles which are strongly suppressive to reproductive physiology. In this manner, decreasing day lengths of the fall are involved with suppressing sexual capability in male and female hamsters. Throughout the winter months darkness (because of the shorter day lengths and the fact that hamsters remain underground in lightless burrows) holds the gonads in an atrophic condition and thereby prevents hamsters from breeding. As spring approaches the neuroendocrine reproductive axis becomes refractory to the inhibitory effects of darkness and the pineal gland and, as a consequence, the gonads recrudesce allowing the animals to successfully reproduce. The long days of the spring and summer serve to interrupt the refractory period so that when winter approaches shortening day lengths will again, by way of the pineal gland, induce gonadalinvolution. In this scheme both light and darkness are critically important in synchronizing the phases of the annual reproductive cycle of the hamster with the appropriate season of the year. Melatonin may be the pineal hormone which mediates the effects of darkness on reproductive physiology.