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Background The oral sugar test (OST) is commonly used to diagnose insulin dysregulation (ID) and equine metabolic syndrome; however, possible seasonal changes in OST results have not been evaluated. Objective To determine the possible variation in insulin response to OST throughout the year and risk factors associated with maximum insulin concentration (InsMax) and ID. Study design Prospective, longitudinal cohort study. Methods The oral sugar test was performed on 29 Finnhorses every other month six times. Serum total adiponectin concentration and phenotypic variables related to obesity were also measured. Changes in InsMax, adiponectin, scale weight, body condition score, cresty neck score, and fasting glucose concentration were assessed. Risk factor analyses were performed on InsMax and ID status, and ID groups were compared with each other. Results Fourteen horses were categorised with non-ID each time and 15 as having ID at least once during the follow-up period. The ID status of 12 horses varied throughout the year, but neither the insulin variables measured during the OST nor adiponectin expressed significant seasonal variation. Increasing age and cresty neck score, and decreasing adiponectin were observed as risk factors for a high InsMax after OST. The risk of ID was higher in horses with no exercise compared to horses with exercise (OR 7.6, 95% CI 1.2-49.3, p = 0.03). Horses with ID had lower serum adiponectin concentrations, longer neck circumference and larger height than horses in the non-ID group. Main limitations The environmental conditions (feeding, exercise) were not constant for all horses throughout the study and only one breed was used. Conclusions Neither OST results nor adiponectin varies with season; however, there were a substantial number of horses with variable ID status throughout the year, in which repeated OSTs may be beneficial. Lack of exercise was a risk factor for ID.

14 páginas, 17 figuras, 25 tablas, Many plant species produce multiple leaf flushes during the growing season, which might have major consequences for within-plant variation in chemistry and species interactions. Yet, we lack a theoretical or empirical framework for how differences among leaf flushes might shape variation in damage by insects and diseases. We assessed the impact of leaf flush identity on leaf chemistry, insect attack and pathogen infection on the pedunculate oak Quercus robur by sampling leaves from each leaf flush in 20 populations across seven European countries during an entire growing season. The first leaf flush had higher levels of primary compounds, and lower levels of secondary compounds, than the second flush, whereas plant chemistry was highly variable in the third flush. Insect attack decreased from the first to the third flush, whereas infection by oak powdery mildew was lowest on leaves from the first flush. The relationship between plant chemistry, insect attack and pathogen infection varied strongly among leaf flushes and seasons. Our findings demonstrate the importance of considering differences among leaf flushes for our understanding of within-tree variation in chemistry, insect attack and disease levels, something particularly relevant given the expected increase in the number of leaf flushes with climate change., The authors acknowledge the Bolin Centre for Climate Research (RA8) for supporting this project (2015-03993 and 2021-03784 to AJMT). PDF and CM received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC Starting Grant FORMICA 757833).

Traditionally, research unraveling seasonal neuroplasticity in songbirds has focused on the male song control system and testosterone. We longitudinally monitored the song behavior and neuroplasticity in male and female starlings during multiple photoperiods using Diffusion Tensor and Fixel-Based techniques. These exploratory data-driven whole-brain methods resulted in a population-based tractogram confirming microstructural sexual dimorphisms in the song control system. Furthermore, male brains showed hemispheric asymmetries in the pallium, whereas females had higher interhemispheric connectivity, which could not be attributed to brain size differences. Only females with large brains sing but differ from males in their song behavior by showing involvement of the hippocampus. Both sexes experienced multisensory neuroplasticity in the song control, auditory and visual system, and cerebellum, mainly during the photosensitive period. This period with low gonadal hormone levels might represent a ‘sensitive window’ during which different sensory and motor systems in the cerebrum and cerebellum can be seasonally re-shaped in both sexes.

WOS: 000475489500002, Histomorphological structure of the liver of Ranidae species during the reproduction period contribute significantly to the production rate in the frog culture studies. In this study, the cytoplasmic status of hepatocytes, lipid and melanin pigment in liver parenchyma of adult male and female Pelophylax ridibundus (Pallas, 1771) were investigated before and after reproduction. For histological studies, adult frogs were collected from nature and placed in production ponds to examine the reproduction process. In this study, twenty four breeding male frogs, with average weight 36.63 +/- 12.84 g and length 69.29 +/- 9.15 mm, and twenty four breeding females with average weight and length of 56.61 +/- 19.59 g and 79.54 +/- 7.07 mm were used. Samples from the liver tissue of frog were taken in 2015 during (March) and after reproduction (June) period. Histologically pictures of liver parenchyma were taken from the as homogeneous fields as possible. Before the reproduction, it was found that the liver parenchyma of the female frogs were cytoplasmically intense, with a low amount of melanin pigment and lipid droplets. Similarly, male frogs liver parenchyma and hepatocytes were found to be cytoplasmically intense, containing a low amount of melanin pigment and lipid droplets. Both female and male frogs completed the reproduction in April and May. After reproduction period, a great amount of melanin pigment in the liver parenchyma was observed and the cytoplasmic density of the hepatocytes decreased. As a result, cytoplasmic decrease in hepatocytes, structural changes and increase in melanin pigments supports the idea that glycogen and lipids stored in the liver parenchyma are used for reproduction.

Elemental (CHN) and proximate biochemical compositions of body tissues are useful tools among the ecological indices most commonly used in evaluation of the energetic status of animal populations. Gnaiger and Bitterlich (1984) supplied procedures for the interconversion between both these measurements based on stoichiometric relationships, that were further tested using gut contents and body tissue samples of freshwater fishes. Despite a lack of validation studies, the reported conversion factors have been broadly applied in the field of body composition analysis of marine invertebrates, especially bivalve mollusks. The aim of this study was to test the applicability of those conversion equivalents in analysis of the body tissues of two congeneric clam species (Ruditapes decussatus and Ruditapes philippinarum). To this end, proximate biochemical composition, as analyzed by fractionated extraction of tissues samples and quantification using spectrophotometric methods, was converted to elemental composition, and the resulting figures were compared with those of direct CHN analysis. The results of this comparison indicate good agreement within the ranges reported, provided that ninhydrin positive substances (NPS) are incorporated in the biochemical composition analyses. The magnitude of the nonprotein N component in bivalve tissues appears to complicate the reverse computation of biochemical components from elemental composition because no accurate estimation of proteins from N contents might be possible. Additionally, a specific correction of residual water in dried samples of bivalve tissues for CHN analysis should be applied. The absence of broad differences found between species reflects the morphological, evolutionary and functional proximity between them, whereas tissue differences display the differential role that each organ plays in the organism, although other sources of variability such as diet and sex should be addressed in future research. This work was supported by the Spanish Ministry of Economy and Competitiveness (AGL2013-49144-C3-1-R). K. Arranz was funded by a predoctoral research grant from Universidad del Pais Vasco/Euskal Herriko Unibertsitatea (UPV/EHU). SGIker technical and human support (UPV/EHU, MICINN, GV/EJ, ESF) is gratefully acknowledged.

Centro de Investigación Forestal (CIFOR), Key message: Local adaptation largely segregates between traits affecting light responses and water relations, but population-level differences in stomatal conductance when growth is unconstrained converge among populations under water stress. Abstract: Warming temperatures and altered precipitation patterns threaten plant populations worldwide. European beech (Fagus sylvatica) is a species that expresses both high phenotypic plasticity and local adaptation among populations. Beech seedlings’ susceptibility to prolonged drought may be dictated by their immediate light environment. We tested whether seedlings of four beech provenances, from contrasting edaphoclimatic environments, expressed differences in trait responses to imposed water stress under sun and shade treatments. Populations from the southern range margin were expected to display greater water-stress tolerance and core populations’ faster growth rates in the absence of abiotic limitations. Both high light and water stress induced differences in trait responses among provenances, but traits that failed to respond to our experimental treatments likewise did not segregate at the provenance level. Hence, those traits responding to light, e.g., increasing leaf flavonol index and leaf mass area, also tended to differ among provenances. Similarly, there was evidence of local adaptation among provenances in traits, like midday leaf water potential, responding to water stress. Exceptionally, there was a three way interaction water- × -light- × -provenance for stomatal conductance which converged among provenances under water stress. Leaf chlorophyll content also varied both with light and water in a provenance-specific manner. We found core provenances’ growth traits to outperform others under favourable conditions, whereas southern and high-elevation populations displayed traits adapted to tolerate high irradiance. Only stomatal conductance produced a complementary interactive response between light- × -water across provenances, whereas other traits responded less to combined water stress and high irradiance than to either treatment alone., Open access funding provided by University of Helsinki including Helsinki University Central Hospital. This project was initiated during the COST Action E52, “Evaluation of beech genetic resources for sustainable forestry”. We are grateful to Gerhard Huber of the Bavarian Office for Forest Seeding and Planting in Teisendorf, and to Rolf Övergaard of the Southern Swedish Forest Research Centre in Alnarp, for supplying the beech nuts. This work was supported by a grant from the Spanish Ministry of Education and Science to the project CLIMHAYA-BOSALIM CGL2007-66066-C04-03/BOS and Juan de la Cierva Fellowships to T.M.R. and D.S.G. The authors are grateful to the Autonomous Community of Madrid (CAM) for permission to work at el Hayedo de Montejo. The research was supported by the University of Helsinki and Academy of Finland decision 116775 to P.J.A, decision 304519 to T.M.R. and Chinese Scholarship Council to F.W. We thank Noora Imberg for helping to do the experimental work., 15 Pág.

Increased numbers of great cormorants (Phalacrocorax carbo) in the Baltic Sea may have local impacts on fisheries and salmonid hatcheries. We studied spatial and temporal variability in cormorant diet, and potential consumption of hatchery salmonids, by analysing knee subcutaneous adipose tissue fatty acids (FA) of specimens (N = 77) collected along Swedish and Finnish coasts in different seasons during 2013–2017. The FA profiles of the subspecies sinensis and carbo were similar, with large individual variation. The proportion of C18 polyunsaturated FAs (PUFAs) was the largest in the north, whereas the proportion of C20–22 monounsaturated FAs (MUFAs) increased towards the south, reflecting diminishing freshwater and increasing marine food web characteristics towards the south. As an exception, the C20–22 MUFA percentage was high in sinensis collected in June 2017 from the northern Baltic Sea. The source of C20–22 MUFAs was probably hatchery salmonids, raised on ocean fish hatchery feed and released 10 days before, near the cormorant capture site. The FA profiles of northern and southern cormorants differed from each other both in early and late summer samples, suggesting spatially different diets. The largest individual variation was found in 22:1n-11, characteristic of ocean zooplanktivorous fish, and likely originating from Atlantic wild or Baltic Sea hatchery-reared fish. This study shows that adipose tissue FA profiles can be used as proxies for seabird diet monitoring and indicators of predation on hatchery-reared fish. Obtaining quantitative estimates on the proportions of dietary fish species requires future feeding experiments, allowing calibration between the FA compositions and diet.

The rates of dehardening and rehardening in response to rapid temperature changes in winter are important traits that affect the survival, growth and productivity of the European pear (Pyrus communis [L.]) cultivars in northern countries. The frost hardiness (FH) of shoots of three pear cultivars were studied by a series of freezing tests, after sampling in natural conditions, after dehardening in a growth chamber at 5 degrees C for 3-4 days (D1) and 16 days (D2), and then after rehardening at -7 degrees C for 5-7 days (R1 and R2). The FH was assessed by a differential thermal analysis (DTA) to measure the low temperature exotherm (LTE) of shoots, by relative electrolyte leakage (REL) of shoots and by visual damage scoring (VD) of shoots and buds. According to the DTA, the FH of the cultivars varied between -38 degrees C ('Conference' in D2) and -41 degrees C ('Pepi' in R2). The shoots of the cultivar 'Pepi' and 'Conference' had the highest and the lowest FH, respectively, in all conditions and methods. All the cultivars had the lowest shoot FH after dehardening in either D1 (between -26 degrees C and -30 degrees C by REL and between -28 degrees C and -30 degrees C by VD) or D2 (between -38 degrees C and -40 degrees C by DTA), and the highest FH after rehardening (R1) preceded by D1 (between -30 degrees C and -34 degrees C by REL, and between -29 degrees C and -32 degrees C by VD). After the dehardening in D1, the buds did not reharden but continued to deharden (the average FH by VD - 24.5 degrees C). In the forcing conditions, bud growth was resumed most rapidly in 'Conference', indicating a shallower dormancy in this cultivar than in 'Pepi' or 'Clara Frijs'. We conclude that the pear cultivars responded to temperature changes in mid-winter, but less than expected, and the responses were similar in all cultivars.

Macrofauna play a key role in the functioning of mangrove ecosystems. Nevertheless, our understanding of the diversity and functional structure of macrofaunal communities across different habitats in the mangrove forests of the Persian Gulf is limited. In this study, we investigated species diversity and biological trait patterns of macrofauna in different mangrove-associated habitats, i.e., encompassing actual mangrove forests, and adjacent Beaches and Creeks, which exhibit different levels of habitat heterogeneity. Samples were collected from the different habitats in five different locations, over four seasons. A total of 122 macrofauna taxa were identified. The diversity of species was higher in summer than in winter. In the Beach habitats, species diversity showed an increasing trend from land toward the mangrove, whereas in Creek habitats diversity decreased from the Creek toward the mangrove. Multivariate community analysis showed differences in the distribution of abundant species and biological traits across all habitats. Deposit-feeding, crawlers, medium-size, and free-living were the dominant trait modalities in all habitats. The similarities within habitats over the four seasons had the same specific pattern of species and biological trait abundance in the Beach and the Creek, increasing from the non-covered habitat into the mangrove trees. Although many species shared similar traits, the abundance-driven differences in trait expression between habitats showed the importance of habitat filtering. The results of this study will be useful in the conservation of mangrove forests and they give a deeper understanding of the ecological patterns and functions of benthic macrofaunal communities in the Persian Gulf.

Coping of evergreen conifers in boreal forests with freezing temperatures on bright winter days puts the photosynthetic machinery in great risk of oxidative damage. To survive harsh winter conditions, conifers have evolved a unique but poorly characterized photoprotection mechanism, a sustained form of nonphotochemical quenching (sustained NPQ). Here we focused on functional properties and underlying molecular mechanisms related to the development of sustained NPQ in Norway spruce (Picea abies). Data were collected during 4 consecutive years (2016 to 2019) from trees growing in sun and shade habitats. When day temperatures dropped below -4 degrees C, the specific N-terminally triply phosphorylated LHCB1 isoform (3p-LHCII) and phosphorylated PSBS (p-PSBS) could be detected in the thylakoid membrane. Development of sustained NPQ coincided with the highest level of 3p-LHCII and p-PSBS, occurring after prolonged coincidence of bright winter days and temperatures close to -10 degrees C. Artificial induction of both the sustained NPQ and recovery from naturally induced sustained NPQ provided information on differential dynamics and light-dependence of 3p-LHCII and p-PSBS accumulation as prerequisites for sustained NPQ. Data obtained collectively suggest three components related to sustained NPQ in spruce: 1) Freezing temperatures induce 3p-LHCII accumulation independently of light, which is suggested to initiate destacking of appressed thylakoid membranes due to increased electrostatic repulsion of adjacent membranes; 2) p-PSBS accumulation is both light -and temperature-dependent and closely linked to the initiation of sustained NPQ, which 3) in concert with PSII photoinhibition, is suggested to trigger sustained NPQ in spruce.

The farming of the non-indigenous bay scallop Argopecten irradians in coastal waters generates large amounts of biodeposits that potentially change the trophic pathways and quality of the benthic food web at lower trophic levels such as meiobenthos. To understand the trophic link between faecal pellets of bay scallop and meiobenthos in the aquaculture area, we investigated the resource use of harpacticoid copepods and nematodes inside and outside of 3 bay scallop farms in Laizhou Bay (Bohai Sea, China) using natural abundance of stable carbon and nitrogen isotopes together with fatty acid profiling. Faeces were found to be enriched in δ15N compared to all other food sources, which made faecal matter traceable. The enriched δ15N in several meiobenthos at the farms, together with the mixing model results, indicated that faeces could be a new food source for most of harpacticoid copepods and some nematodes. The quantities and the pathways of assimilation differed between the copepod families, depending on their feeding behaviors and the receiving environment. Furthermore, due to the presence of higher levels of polyunsaturated fatty acids, in particular docosahexaenoic acid, the dominant copepod family Canuellidae that abundantly consumed scallop faeces showed enhanced nutritional quality compared with those in the control sites. Thus, aquaculture of non-indigenous bay scallops provided a food source that was directly and indirectly consumed by meiobenthos underneath the scallop farms and improved the quality of lower level consumers as a food item in the benthic food web.

Divergence in the onset of reproduction can act as an important source of reproductive isolation (i.e., allochronic isolation) between co-occurring young species, but evidence for the evolutionary processes leading to such divergence is often indirect. While advancing spring seasons strongly affect the onset of reproduction in many taxa, it remains largely unexplored whether contemporary spring advancement directly affects allochronic isolation between young species. We examined how increasing spring temperatures affected onset of reproduction and thereby hybridization between pied and collared flycatchers (Ficedula spp.) across habitat types in a young secondary contact zone. We found that both species have advanced their timing of breeding in 14 years. However, selection on pied flycatchers to breed earlier was weaker, resulting in a slower response to advancing springs compared to collared flycatchers and thereby build-up of allochronic isolation between the species. We argue that a preadaptation to a broader niche use (diet) of pied flycatchers explains the slower response to raising spring temperature, but that reduced risk to hybridize may contribute to further divergence in the onset of breeding in the future. Our results show that minor differences in the response to environmental change of co-occurring closely related species can quickly cause allochronic isolation.

WOS:000427804800018; In this study, we combined remote sensing data and in situ observations to explore the potential habitats of macroalgae at Libukang Island, Indonesia. High-resolution satellite images from the GeoEye-1 were used to estimate and to map the geomorphological structures together with macroalgal species in the study area. Seasonal variations of percentage cover and biomass of macroalgae associated with substrates were investigated in May and November 2014, and June 2015, using quadrats as sampling unit. A total of nine common genera were found in the study area with three dominant genera: Sargassum, Padina, and Turbinaria. Most of macroalgae was observed in the eastern part of the Island, on several substrate types and particular oceanographic conditions (wave and current). Mean biomasses of Sargassum and Padina were high in May (1189.6 +/- 455 and 166.7 +/- 15.4 g DW.m(-2), respectively), while the biomass of Turbinaria was high in November (3245 +/- 599.8 g DW.m(-2)). The map accuracy of image classification for all typology substrates was 74.19%. Overall, approximately 62.3% of the total study area can be considered as potential for natural macroalgae habitats. Spectral response characteristic of shallow water substrates at study area based on GeoEye-1 is also presented. The results of this study exhibit a potential utilization of natural macroalgae in the study area, and provide information for a possible diversification of the use of macroalgae in Indonesia. The method could be useful for habitat management and future biomonitoring in the study area or other similar areas in Indonesia.

Some equatorial environments exhibit substantial within-location variation in environmental conditions throughout the year and yet have year-round breeding birds. This implies that breeding in such systems are potentially unrelated to the variable environmental conditions. By breeding not being influenced by environmental conditions, we become sure that any differences in immune function between breeding and non-breeding birds do not result from environmental variation, therefore allowing for exclusion of the confounding effect of variation in environmental conditions. This create a unique opportunity to test if immune function is down-regulated during reproduction compared to non-breeding periods. We compared the immune function of sympatric male and female chick-feeding and non-breeding red-capped Calandrella cinerea and rufous-naped larks Mirafra africana in equatorial East Africa. These closely-related species occupy different niches and have different breeding strategies in the same grassland habitat. Red-capped larks prefer areas with short grass or almost bare ground, and breed during low rainfall periods. Rufous-naped larks prefer areas of tall grass and scattered shrubs and breed during high rainfall. We measured the following immune indices: nitric oxide, haptoglobin, agglutination and lysis, and measured total monthly rain, monthly average minimum (T-min) and maximum (T-max) temperatures. Contrary to our predictions, we found no down-regulation of immune function during breeding; breeding birds had higher nitric oxide than non-breeding ones in both species, while the other three immune indices did not differ between breeding phases. Red-capped larks had higher nitric oxide concentrations than Rufous-naped larks, which in turn had higher haptoglobin levels than red-capped larks. T-max was higher during breeding than during non-breeding for red-capped larks only, suggesting potential confounding effect of T-max on the comparison of immune function between breeding and non-breeding birds for this species. Overall, we conclude that in the two year-round breeding equatorial larks, immune function is not down-regulated during breeding.

The hypothalamic-pituitary-adrenal (HPA) axis is under complex regulatory control at multiple levels. Enzymatic regulation plays an important role in both circulating levels of glucocorticoids and target tissue exposure. Three key enzyme pathways are responsible for the immediate control of glucocorticoids. De novo synthesis of glucocorticoid from cholesterol involves a multistep enzymatic cascade. This cascade terminates with 11 beta-hydroxylase, responsible for the final conversion of 11-deoxy precursors into active glucocorticoids. Additionally, 11 beta-hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) controls regeneration of glucocorticoids from inactive metabolites, providing a secondary source of active glucocorticoids. Localized inactivation of glucocorticoids is under the control of Type 2 11 beta-HSD (11 beta-HSD2). The function of these enzymes is largely unexplored in wild species, particularly songbirds. Here, we investigated the contribution of both clearance and generation of glucocorticoids to regulation of the hormonal stress response via the use of pharmacological antagonists. Additionally, we mapped 11 beta-HSD gene expression. We found 11 beta-HSD1 primarily in liver, kidney and adrenal glands, although it was detectable across all tissue types. 11 beta-HSD2 was predominately expressed in the adrenal glands and kidney with moderate gonadal and liver expression. Inhibition of glucocorticoid generation by metyrapone was found to decrease levels peripherally, while both peripheral and central administration of the 11 beta-HSD2 inhibitor DETC resulted in elevated concentrations of corticosterone. These data suggest that during the stress response, peripheral antagonism of the 11 beta-HSD system has a greater impact on circulating glucocorticoid levels than central control. Further studies should aim to elucidate the respective roles of the 11 beta-HSD and 11 beta-hydroxylase enzymes.

The widespread use of motor oil makes it a notable risk factor to cause scattered contamination in soil. The monitoring of microbial community dynamics can serve as a comprehensive tool to assess the ecological impact of contaminants and their disappearance in the ecosystem. Hence, a field study was conducted to monitor the ecological impact of used motor oil under different perennial cropping systems (fodder galega, brome grass, galega-brome grass mixture and bare fallow) in a boreal climate zone. Length heterogeneity PCR characterized a successional pattern in bacterial community following oil contamination over a four-year bioremediation period. Soil pH and electrical conductivity were associated with the shifts in bacterial community composition. Crops had no detectable effect on bacterial community composition or complexity. However, the legume fodder galega increased soil microbial biomass, expressed as soil total DNA. Oil contamination induced an abrupt change in bacterial community composition at the early stage, yet the effect did not last as long as the oil in soil. The successional variation in bacterial community composition can serve as a sensitive ecological indicator of oil contamination and remediation in situ. (C) 2015 Elsevier B.V. All rights reserved.

We analysed changes in the abundance, biomass and cell size of the microbial food web community (bacteria, heterotrophicnanoflagellates, ciliates) at contrasting nutrient concentrations and temperatures during a simulated heat wave. We used 24mesocosms mimicking shallow lakes in which two nutrient levels (unenriched and enriched by adding nitrogen and phosphorus)and three different temperature scenarios (ambient, IPCC A2 scenario and A2+%50) are simulated (4 replicates of each).Experiments using the mesocosms have been running un-interrupted since 2003. A 1-month heat wave was imitated by anextra 5◦C increase in the previously heated mesocosms (from 1st July to 1st August 2014). Changes in water temperatureinduced within a few days a strong effect on the microbial food web functioning, demonstrating a quick response of microbialcommunities to the changes in environment, due to their short generation times. Warming and nutrients showed synergisticeffects. Microbial assemblages of heterotrophic nanoflagellates and ciliates responded positively to the heating, the increasebeing largest in the enriched mesocosms. The results indicate that warming and nutrients in combination can set off complexinteractions in the microbial food web functioning. This work was supported by MARS project (ManagingAquatic ecosystems and water Resources under multipleStress, EU 7th Framework Programme, contract no.: 603378)and by institutional grant IUT 21-2 of the Estonian Min-istry of Education and Research. The Danish group wasalso supported by PROGNOS (Predicting in-lake RespOnsesto chanGe using Near real time mOdelS – Water JointProgramme Initiative) and AQUACOSM (Network of Lead-ing European AQUAtic MesoCOSM Facilities ConnectingMountains to Oceans from the Arctic to the Mediterranean),the latter also supporting the Turkish group. Yu Cao issupported by NSF-China (31500296) and CSC (The ChinaScholarship Council). This work was supported by MARS project (ManagingAquatic ecosystems and water Resources under multipleStress, EU 7th Framework Programme, contract no.: 603378)and by institutional grant IUT 21-2 of the Estonian Min-istry of Education and Research. The Danish group wasalso supported by PROGNOS (Predicting in-lake RespOnsesto chanGe using Near real time mOdelS – Water JointProgramme Initiative) and AQUACOSM (Network of Lead-ing European AQUAtic MesoCOSM Facilities ConnectingMountains to Oceans from the Arctic to the Mediterranean),the latter also supporting the Turkish group. Yu Cao issupported by NSF-China (31500296) and CSC (The ChinaScholarship Council).

Winter evergreens living in mountainous areas have to withstand a harsh combination of high light levels and low temperatures in wintertime. In response, evergreens can activate a photoprotective process that consists of the downregulation of photosynthetic efficiency, referred to as winter photoinhibition (WPI). WPI has been studied mainly in woody evergreens and crops even when, in many instances, other functional groups such as lichens or bryophytes dominate in alpine and boreal habitats. Thus, we aimed to (1) assess the occurrence of WPI within overwintering evergreens comprising woody species, herbs, mosses and lichens, (2) compare the recovery kinetics among those groups and (3) clarify the role of thylakoid proteins and pigments in both processes: WPI and recovery. With this aim, WPI was analyzed in 50 species in the field and recovery kineticcs were studied in one model species from each functional group. Results showed that high levels of WPI are much more frequent among woody plants than in any other group, but are also present in some herbs, lichens and mosses. Winter conditions almost always led to the de‐epoxidation of the xanthophyll cycle. Nevertheless, changes in the de‐epoxidation level were not associated with the activation/deactivation of WPI in the field and did not match changes in photochemical efficiency during recovery treatments. Seasonal changes in thylakoid proteins [mainly D1 (photosystem II core complex protein) and PsbS (essential protein for thermal dissipation)] were dependent on the functional group. The results highlight the diversity of physiological solutions and suggest a physical–mechanical reason for the more conservative strategy of woody species compared with other groups. Marie Curie IEF grant (328370 MELISSA) from the Euro- pean FP7-PEOPLE and a ‘Juan de la Cierva Incorporación’ grant (IJCI-2014-22489) from the Spanish Ministry of Econ- omy and Competitiveness (MINECO) and the European Regional Development Fund ERDF (FEDER). The work was also supported by the project BFU 2010 – 15021 and CTM2014-53902-C2-2-P from the MINECO and the ERDF (FEDER), and by the Basque Government (UPV/EHU-GV IT-624–13 and UPV/EHU-GV IT-1018-16)

Temporally changing environmental conditions occur in most parts of the world and can exert strong pressure on the immune defense of organisms. Seasonality may result in changes in physiological traits over the year, and such changes may be essential for the optimization of defense against infections. Evidence from field and laboratory studies suggest the existence of links between environmental conditions, such as infection risk, and the ability of animals to mount an immune response or to overcome infections; however, the importance of parasites in mediating seasonal change in immune defense is still debated. In this study, we test the hypothesis that seasonal change in immune function and connected physiological traits is related to parasite infection. We sampled captive house sparrows (Passer domesticus) once every 2 mo over 14 mo and compared the annual variation in 12 measures of condition, immune function, antioxidant status, and oxidative damage among birds naturally infested with coccidians or medicated against these parasites. We found significant variation in 10 of 12 traits over the year. However, we found little support for parasite-mediated change in immune function and oxidative status in captive house sparrows. Of the 12 measures, only one was slightly affected by parasite treatment. In support of the absence of any effect of coccidians on the annual profile of the condition and physiological traits, we found no consistent relationships between the intensity of infestation and these response variables over the year. Our results show that chronic coccidian infections have limited effect on the seasonal changing of physiological traits and that the patterns of these measures are probably more affected by acute infection and/or virulent parasite strains.

Summary Trade-offs between immune function and other physiological and behavioral processes are central in ecoimmunology, but one important problem is how to distinguish a reallocation of resources away from the immune system from a reallocation or redistribution within the immune system. While variation in baseline values of individual immune parameters is well established, studies in wild animals on multiple parameters during an immune response are lacking. It also remains to be tested if and how immune responses correlate with baseline values that vary e.g. over the course of an annual cycle. We studied immunological responses to an endotoxin challenge in skylarks (Alauda arvensis), a partial migrant bird breeding in temperate zones. We compared birds injected with the endotoxin LPS with un-injected controls, characterizing immunological responses with leukocyte profiles, titres of lytic enzymes and natural antibodies, and concentrations of haptoglobin and heat shock proteins. We did this in five annual-cycle stages to test if the response varied throughout the year. The endotoxin challenge affected 6 of 10 measured parameters. Lysis titers and proportions of heterophils increased; haptoglobin concentrations and proportions of lymphocytes, basophils and eosinophils decreased. The variable effects on different immune components demonstrate the complexity of an immune response. We found no evidence that the response differed between annual-cycle stages. The response was independent of baseline measures taken directly upon capture in the field, indicating that birds were facing no immunological ceiling when mounting an immune response. Values of five parameters collected under field conditions were significantly related to values taken under standardised lab conditions. We conclude that multiple parts of the immune system are modulated during an immunological response and that responses are not re-organised throughout the annual cycle.

Reproduction in vertebrates is an energy-demanding process that is mediated by endogenous hormones and potentially results in oxidative stress. The primary aim of this study was to quantify the relationship between oxidative stress parameters (antioxidant capacity and levels of reactive oxygen metabolites) and circulating testosterone and cortisol in a common and widespread teleost fish, the brown trout (Salmo trutta. L). Results show that trout with higher testosterone levels prior to spawning have higher levels of oxidative damage at the time that they spawn (although by the time of spawning testosterone levels had dropped, leading to a negative relationship between testosterone and oxidative damage at that time). Cortisol levels were not directly related to oxidative damage or antioxidant capacity, but concentrations of this hormone were positively related to levels of fungal infection, which was itself associated both with lower antioxidant capacity and lower levels of oxidative damage. These results highlight the complexity of interactions between different components of the endocrine system and metabolism and suggest that caution be used in interpreting relationships between a single hormone and indicators of oxidative balance or other fitness proxies. (C) 2012 Elsevier Inc. All rights reserved.

The aims of this paper was to modify the photosynthesis model of Farquhar, von Caemmerer and Berry (FvCB) to be able to predict light dependency of the carboxylation capacity ( V c ) and to improve the prediction of temperature dependency of the maximum carboxylation capacity ( V cmax ) and the maximum electron transport rate ( J max ). The FvCB model was modified by adding a sub-model for Ribulose-1,5-bisphosphate carboxylase (Rubisco) activation and validating the parameters for temperature dependency of V cmax and J max . Values of parameters for temperature dependency of V cmax and J max were validated and adjusted based on data of the photosynthesis response to temperature. Parameter estimation was based on measurements under a wide range of environmental conditions, providing parameters with broad validity. The simultaneous estimation method and the nonlinear mixed effects model were applied to ensure the accuracy of the parameter estimation. The FvCB parameters, V cmax , J max , α (the efficiency of light energy conversion), θ (the curvature of light response of electron transport), and R d (the non-photorespiratory CO 2 release) were estimated and validated on a dataset from two other years. Observations and predictions matched well ( R 2 = 0.94). We conclude that incorporating a sub-model of Rubisco activation improved the FvCB model through predicting light dependency of carboxylation rate; and that estimating V cmax , J max , α , θ , and R d requires data sets of both CO 2 and light response curves.

Oscillatory and longitudinal time patterns play a major role in human physiology. In chronic hemodialysis patients, abnormalities in both time patterns have been observed, while time patterns can also influence the response of patients to the treatment. Abnormal oscillatory patterns have been observed for ultradian rhythms (cycle time 28 h) rhythms, large seasonal differences in mortality, but also in blood pressure and interdialytic weight gain, have been observed in dialysis patients. The most important longitudinal pattern is the general reduction of life span in dialysis patients. One explanation of this phenomenon relates to the concept of accelerated aging in dialysis patients, for which there are various supportive arguments. From a phenomenological point of view, this concept translates into the high prevalence of frailty, even in young dialysis patients. A multidimensional approach appears necessary to adequately address this problem. In this review, the relevance of disturbed time patterns in dialysis patients is discussed. The changes may reflect an impairment or reduction in homeostatic/homeodynamic control in dialysis patients and also may have important prognostic and therapeutic implications.

The bark tissues were collected from 4-year-old sweet cherry trees cvs. 0900 Ziraat and Lambert grafted on Gisela 5 and Mazzard rootstocks in cold-acclimated (CA) and nonacclimated (NA) stages. Bark tissues subjected to 4 degrees C and -5 degrees C injured to a limited extent in both stages. However, more than 50% injury occurred by temperatures equal to or colder than -15 degrees C only in NA period. Total soluble sugar (TSS), reducing sugars, and sucrose contents were higher in CA than those in NA stages in all samples. The activities of acid invertase (EC 3.2.1.26) and sucrose synthase (SS) (EC 2.4.2.13) enzymes were higher in NA stage than those in CA stage. Considering the rootstocks, reducing sugars were higher in both cultivars grafted on Gisela 5 whereas sucrose contents were higher in both cultivars grafted on Mazzard. However, the enzyme activities of both cultivars were higher on Mazzard rootstock than on Gisela 5. In conclusion, cold hardiness of sweet cherry graft combinations was suggested by increasing their TSS, reducing sugars, and sucrose contents significantly in the CA stage. Moreover, acid invertase and SS are down regulated during cold acclimation. Indeed the results suggested that Mazzard is more cold-hardy rootstock than Gisela 5.

The European eel Anguilla anguilla has a complex life cycle that includes freshwater, seawater and morphologically distinct stages as well as two extreme long distance migrations. Eels do not feed as they migrate across the Atlantic to the Sargasso Sea but nevertheless reach sexual maturity before spawning. It is not yet clear how existing energy stores are used to reach the appropriate developmental state for reproduction. Since the liver is involved in energy metabolism, protein biosynthesis and endocrine regulation it is expected to play a key role in the regulation of reproductive development. We therefore used microarrays to identify genes that may be involved in this process. Using this approach, we identified 231 genes that were expressed at higher and 111 genes that were expressed at lower levels in sexually mature compared with immature males. The upregulated set includes genes involved in lipid metabolism, fatty acid synthesis and transport mitochondrial function, steroid transport and bile acid metabolism. Several genes with putative enzyme functions were also expressed at higher levels at sexual maturity while genes involved in immune system processes and protein biosynthesis tended to be down-regulated at this stage. By using a high-throughput approach, we have identified a subset of genes that may be linked with the mobilization of energy stores for sexual maturation and migration. These results contribute to an improved understanding of eel reproductive biology and provide insight into the role of the liver in other teleosts with a long distance spawning migrations. (C) 2015 Elsevier Inc. All rights reserved.

In this study, one-year-old shoots of the olive (Olea europaea L.) cv. Gemlik were tested at artificial low temperatures (4, -5A degrees C, -10A degrees C, and -20A degrees C) every month for two years. For low temperature treatment, the degree of cell membrane injury in leaves and barks was determined by ion leakage method. In addition, with regard to antioxidative defense mechanism, activities of catalase (CAT, EC 1.11.1.6) and ascorbate peroxidase (APX, EC 1.11.1.11) enzymes were determined. Leaf and bark tissues subjected to 4A degrees C and -5A degrees C injured to a limited extent in all months. However, more than 50% injury occurred by temperatures equal to or colder than -10A degrees C treatments depending on the season. For -10A degrees C and -20A degrees C treatments, the lowest and the highest injury in leaf and bark tissues were detected during winter and summer seasons, respectively. We determined in this study that CAT and APX enzyme activities are generally higher during fall and winter compared with those in summer. On the other hand, CAT and APX enzyme activities started increasing during fall along with a decreasing freezing injury while the activities of these enzymes decreased to some extent during winter when freezing injury was the lowest. In addition, while CAT activity decreased with low temperature treatments, APX activity did not change until -5A degrees C treatment but decreased with decreasing temperatures starting from -10A degrees C depending on the month the tissue was obtained. In conclusion, olive plant shows considerable tolerance to low temperatures that are achieved after daily gradual decreases by increasing cell membrane stability through complicated mechanisms including antioxidative enzyme metabolisms. In addition, APX may be more effective in maintaining cold-hardiness of olive compared with CAT. Türkiye Cumhuriyeti Devlet Planlama Teşkilatı

A conceptual model was tested for explaining environmental and physiological effects on leaf gas exchange in the deciduous dry tropical woodland tree Boswellia papyrifera (Del.) Hochst. For this species we aimed at (i) understanding diurnal patterns in leaf gas exchange, (ii) exploring cause-effect relationships among external environment, internal physiology and leaf gas exchange, and (iii) exploring site differences in leaf gas exchange in response to environmental variables. Diurnal courses in gas exchange, underlying physiological traits and environmental variables were measured for 90 trees on consecutive days at two contrasting areas, one at high and the other at low altitude. Assimilation was highest in the morning and slightly decreased during the day. In contrast, transpiration increased from early morning to midday, mainly in response to an increasing vapor pressure deficit (VPD) and gradual stomatal closure. The leaf water potential varied relatively little and did not influence gas exchange during the measurement period. Our results suggest that the same cause-effect relationships function at contrasting areas. However, leaves at the higher altitude had higher photosynthetic capacity, reflecting acclimation to higher light levels. Trees at both areas nevertheless achieved similar leaf assimilation rates since assimilation was down-regulated by stomatal closure due to the higher VPD at the higher altitude, while it became more light limited at the lower altitude. Gas exchange was thus limited by a high VPD or low light levels during the wet season, despite the ability of the species to acclimate to different conditions.

Mammalian hibernation consists of torpor phases when metabolism is severely depressed, and T can reach as low as approximately -2 degrees C, interrupted by euthermic arousal phases. Hibernation affects the function of the innate and the adaptive immune systems. Torpor drastically reduces numbers of all types of circulating leukocytes. In addition, other changes have been noted, such as lower complement levels, diminished response to LPS, phagocytotic capacity, cytokine production, lymphocyte proliferation, and antibody production. Hibernation may therefore increase infection risk, as illustrated by the currently emerging WNS in hibernating bats. Unraveling the pathways that result in reduced immune function during hibernation will enhance our understanding of immunologic responses during extreme physiological changes in mammals. J. Leukoc. Biol. 88: 619-624; 2010.

Changes in the onset of sexual maturation, reproductive investment and growth of North Sea plaice are studied between three periods: 1900s, 1980s and 2000s. Probabilistic maturation reaction norms of both males and females, describing the probability of becoming mature conditional on age and size, shifted towards smaller sizes and younger ages, indicating a fisheries-induced evolutionary change. A higher rate of change was observed during the past 20 years, which may be related to higher temperature conditions. Reproductive investment was estimated from the decrease in lipid, protein, dry weight content and condition factor of the whole body between pre- and post-spawning adults. Reproductive investment expressed as the energy loss over the spawning period increased with body size from 19% at 20 cm to 30% at 40 cm in males and from 35% at 30 cm to 48% at 50 cm in females. No change in reproductive investment could be detected between the 1980s and the 2000s. Von Bertalanffy (VB) growth parameters showed a decrease in L(infinity) the asymptotic size and an increase in K, the velocity to reach L(infinity), in both males and females. The changes in VB growth are consistent with an increase in energy acquisition and reproductive investment. The observed changes in maturation, reproductive investment and growth are consistent with fisheries-induced evolution, but the changes in reproductive investment and growth need further investigation to disentangle the role of phenotypic plasticity. (C) 2009 Elsevier B.V. All rights reserved.

A large-scale field experiment on the drying behavior of Norway Spruce (Picea abies Karst.) and Sweet Chestnut (Castanea sativa Mill.) in relation to the felling date was conducted over a period of 24 weeks in order to investigate the existence of variations linked to lunar rhythms, which are mentioned as having a role in many traditional forestry practices. The measured criteria were the water loss from fresh to dry state, the shrinkage linked to this water loss, and the relative density (ratio between the dry density and the initial fresh density) for both sapwood and heartwood in Picea and heartwood in Castanea. In addition to seasonal trends, slight but significant variations with lunar periodicities (both synodic and sidereal; to a much lesser extent tropic) characterize the three investigated criteria. These lunar rhythmicities occur in both Picea and Castanea, in heartwood and sapwood. These results raise new questions and perspectives about a rhythmic character of the wood-water relation.

Avian eggs contain maternal androgens that may adjust offspring development to environmental conditions. We review evidence and functional explanations for the relationship between androgen concentrations in avian eggs and male attractiveness. Experimental studies in captive birds show generally positive relationships, but results from correlational and experimental field studies are less consistent, perhaps because they lack a within-female design to control for confounding between-female variation. We analyzed the effect of male attractiveness on yolk levels of maternal androgens in a wild bird, using a correlational and experimental approach with a within-female design. We manipulated the sexually selected UV coloration of the crown feathers of male blue tits (Cyanistes caeruleus) after their female had laid the second egg and measured the subsequent effect on androgen concentrations (testosterone and androstenedione) in the fifth, seventh, and ninth eggs relative to that in the second egg. Levels of testosterone, but not androstenedione, in eggs 5 and 7 were higher for control (attractive) than for UV-reduced (unattractive) males. This effect disappeared in the ninth egg, coinciding with the recovery of UV coloration after manipulation. This suggests that females are capable of rapid adjustments of testosterone deposition in response to changes in their mate's ornamental plumage. However, androgen concentrations in the second egg and pretreatment male crown coloration were not correlated. Possibly, the combination of relatively small variation in UV coloration before treatment and the influence of unknown confounding variables in the correlative approach resulted in insufficient statistical power to detect such a correlation. Copyright 2009, Oxford University Press.

Because of its relatively low tolerance to elevated temperatures, Macoma balthica (L.) may be one of the first important marine species in temperate coastal areas to suffer from a warming climate. For the last few decades, the abundance of the species in the Dutch Wadden Sea has been se- riously declining. At lower latitudes, the southern edge of its range recently shifted several 100s of km to the north. To understand changes in abundance related to high temperatures, we studied short-term population responses to warmer than average seasons using data from a long-term (>35 yr) sampling program in the western Wadden Sea. The observed relationships included reduction of reproductive output and recruitment in years starting with mild winter-spring periods, reduction of adult survival in years with warm summers, reduction of annual migration in ~8 mo olds to more favourable areas in mild winters, reduction of growth rates in warmer than average growing seasons, and enhancement of seasonal weight loss in milder than average winters. We conclude that elevated temperatures nega- tively affect population dynamics of M. balthica in a number of ways, i.e. via recruitment or mortality as well as growth. These negative influences were observed already far below the upper lethal tem- perature of the species and in populations living ~1000 km poleward of the warm edge of the species' range. The outcome of M. balthica's energy balance appears to be decisive for their continued exis- tence by effects not only on individual weights but also on mortality as well as reproduction.

In nature, individuals of short-lived plant species (e.g. annuals, biennials) may grow at different times during the growing season. These plants are therefore exposed to different season-related conditions such as light and temperature, which in turn may have consequences for primary and secondary chemistry of the plant. Despite this, many studies examining plant–consumer interactions are performed in single replicates, which may thus ignore temporal variation in the expression of phenotypic plant traits that affect multitrophic interactions. In the present study, we demonstrated that even under strictly controlled conditions in a greenhouse, secondary plant chemistry changes dramatically in plants growing at different times in a single year, i.e. July, August and November. Glucosinolate (GS) contents in herbivore-damaged leaves of two different crucifer species, Brassica oleracea and Sinapis alba were higher in the August and November replicates than in the July replicate and GS concentrations were 10–25 times higher in S. alba than in B. oleracea. The development of a specialist herbivore, Plutella xylostella, also varied significantly over the three replicates. Larvae of P. xylostella that had fed upon either S. alba or B. oleracea, attained the largest biomass and had the fastest development rate in the November replicate. Female P. xylostella moths grew larger on S. alba than on B. oleracea, whereas male biomass was not significantly affected by host-plant species. Plant species, but not season also affected performance of the endoparasitoid, Diadegma semiclausum. Similar to the performance of host females, parasitoid males developed faster and attained the highest biomass when attacking P. xylostella larvae feeding on S. alba. Most importantly, the performance of the herbivore and its parasitoid only appeared to partially conform to levels of GS in damaged leaves, indicating that there is a complex of factors involved in determining the effects of plant quality on higher trophic levels.

Annual patterns of cold hardiness, total soluble sugars (TSS) and proteins (TSP) were characterised during two consecutive years (May 2003-April 2005) in leaf and bark tissues of olive (Olea europaea L.) 'Gemlik' trees. One-year-old shoots from 13-year-old olive trees were collected each month and exposed to low temperature at 4 degrees C, -5 degrees C, -10 degrees C, or -20 degrees C for 12 h to determine their cold-hardiness (LT50; assessed by electrolyte leakage). A considerable increase in cold-hardiness was observed with decreasing temperature. Leaf and bark tissues exhibited an increase in cold-hardiness during the Autumn, which reached a maximum in mid-Winter, then gradually decreased during the Spring, and reached a minimum in mid-Summer. Results indicated that leaf and bark tissues in both experimental years responded similarly to cold, with a continuous increase in their TSS and TSP contents during field adaptation in Autumn and Winter, which paralleled their cold-hardiness. The annual cycle of TSP from leaf and bark tissue was characterised by one dimensional SDS-PAGE. A seasonal fluctuation was observed in leaf proteins of 66 kDa and 43 kDa, and in bark proteins of 70 kDa, 43 kDa and 16 kDa, which paralleled cold-acclimation. Evaluation of these leaf and bark TSP profiles showed that these polypeptides disappeared in the Summer, followed by their accumulation again during the Autumn and Winter. Moreover, all these polypeptides became less visible during the Spring. The relationships between these five proteins, TSS contents, and cold-hardiness in olive are discussed.

Structurally-based ultraviolet (UV) coloration of plumage can signal male quality and plays a role in female mate choice in many bird species. UV-reflecting badges could also be important signals in male-male competition. We tested if territorial blue tit ( Cyanistes caeruleus ) males discriminate between conspecific male intruders which differ in the UV reflectance of their crown feathers. To this aim, we used a new experimental approach in which we simultaneously (instead of sequentially) introduced two male blue tit taxidermic mounts in the territories of resident males during the female fertile period; one mount with natural crown UV reflectance and one mount with reduced crown UV. The two mounts provoked strong aggressive reactions from resident males. Males specifically directed their aggression to conspecific intruders, as a male blue tit mount received substantially more aggression than a mount of a European robin ( Erithacus rubecula ). However, aggression of resident males did not vary between the UV-reduced and the control mount. Furthermore, the variation in natural crown UV reflectance of the resident males did not predict the intensity of their aggressive response. Contrary to previous findings our results suggest that UV signals play only a limited role in male-male interactions during territorial intrusions in the female fertile period.

Intake rate maximization alone is not always sufficient in explaining prey size selection in predators. For example, bivalve-feeding oystercatchers regularly select smaller prey than expected if they aimed to maximize their intake rate. It has been proposed that to these birds large prey are ‘‘risky,’’ in the sense that birds may damage their bills when feeding on large bivalves. Large bivalves yield more energy, but according to this hypothesis this is achieved at the expense of energy yield in the long term when (1) the risk of bill damage increases with prey size and (2) foraging with a damaged bill is less effective. In accordance with this hypothesis, we show that captive oystercatchers feeding on large cockles experienced a high probability of bill tip damage, while bill damage was absent when cockles were small. Moreover, among free-living oystercatchers the prevalence of bill damage was correlated with mean cockle size near the capture site, and the data on captive birds fit in this pattern. Food intake of captive oystercatchers feeding exclusively on cockles was reduced by 23% after bill damage, and free-living birds with damaged bills had 14 g lower mass. Because lower body mass was associated with higher mortality probability, these results indicate long-term costs associated with feeding on large cockles. We conclude that the risk of bill damage can potentially explain why oystercatchers avoid large bivalves and that oystercatchers may maximize long-term intake rate by selecting prey sizes that are ‘‘suboptimal’’ from a short-term rate-maximizing point of view. Key words: prey choice, prey profitability, prey size selection, risky prey. [Behav Ecol]

We assessed the trophic status of Leptodora kindtii in the food web of a shallow, eutrophic lake in which 0+ age group fish were the main predators. The mean biomass of 0+ fish during three successive years varied from 0.39 g dry wt m(-2) in the first year to 0.05 g dry wt m(-2)in the second year to 2.49 g dry wt m(-2) in the third year. In the years with high fish biomass, densities of small-bodied (

Migrating birds often complete long non–stop flights during which body energy stores exclusively support energetic demands. The metabolic correlates of such long–distance travel in free–living migrants are as yet poorly studied. Bar–tailed godwits,Limosa lapponica taymyrensis, undertake a 4500 km flight to their single spring stopover site and thus provide an excellent model in which to determine the energy fuels associated with endurance travel. To this end, we evaluated plasma concentrations of six key metabolites in arriving godwits caught immediately upon landing near their stopover site. Initial metabolite levels were compared with levels after 5 h of inactive rest to determine how flightper seaffects energy metabolism. Birds refuelling on the stopover site were also examined. Arriving godwits displayed elevated plasma free fatty acids, glycerol and butyrate, confirming the importance of lipid fuel in the support of extended migratory activity. Furthermore, elevated plasma triglycerides in these birds suggest that fatty acid provisioning is facilitated through hepatic synthesis and release of neutral lipids, as previously hypothesized for small migrants with high mass–specific metabolic rates. Finally, elevations in plasma uric acid suggest that protein breakdown contributes to the support of long–distance movement, to possibly maintain citric acid cycle intermediates, gluconeogenesis and/or water balance.

An object-oriented simulation model was developed to integrate detailed analyses of perennial ryegrass (Lolium perenne) plant part dimensions, and their mass, cell wall content (CWC) and cell wall digestibility (CWD). The model was validated against data from two field experiments, carried out in The Netherlands (52degreesN) and Norway (67degreesN). In the experiments, the effects of temperature x daylength interactions on development, growth and digestibility were determined. Three cultivars differing in heading date were used, and undisturbed growth and regrowth after early (only in The Netherlands) and late cutting were studied. The sensitivity of the model was tested for changes in parameters determining morphological development. A grass plant was modelled as an aggregation of shoot objects. A shoot is an aggregation of phytomers, plus an inflorescence in the reproductive development stage. A phytomer consists of a leaf blade, a leaf sheath, a stem internode and a root. Each phytomer has an axillary bud, which can develop into a new shoot. Morphological development, organic matter (OM) growth and composition were simulated well by the model. Only for regrowing crops in The Netherlands CWC was lower and CWD was higher in the simulations than observed in the field, whereas the differences increased when stem development was more advanced at the moment of cutting. This was attributed to residual stems in the stubble after cutting due to difficulties with machine cutting of lodged crops on the experimental plots. The model can be considered as sufficiently accurate to simulate OM yield and composition of grass cultivars differing in heading date and growing under strongly contrasting temperature and daylength conditions. When the leaf appearance rate, width or length of the leaf blade were increased in the sensitivity analysis, OM yield enhanced, but composition and digestibility of the reproductive grass crops were not systematically affected. (C) 2004 Elsevier B.V. All rights reserved.

Plasma corticosterone increases in association with migratory flight in the red knot Calidris canutus islandica, suggesting that corticosterone may promote migratory activity and/or energy mobilization in this species. This hypothesis is supported by general effects of glucocorticoids, which include stimulation of locomotion and the mobilization of energy depots. We experimentally examined the role of elevated corticosterone levels in the migratory red knot by comparing foraging behavior, flight frequency, and plasma metabolites between vehicle-injected controls and birds treated with RU486, an antagonist to the genomic low-affinity glucocorticoid receptor (GR). We predicted that RU486 treatment would interfere with energy mobilization. However, we expected no effects on flight activity because recent studies suggest that glucocorticoids affect locomotion through a nongenomic receptor. Finally, because glucocorticoids exert permissive effects on food intake, we postulated that RU486 treatment in the red knot would interfere with feeding. Results were consistent with the latter prediction, suggesting that the GR participates in the promotion of hyperphagia, the intense feeding state that is characteristic of the migratory condition. RU486 treatment did not affect flight frequency, suggesting that corticosterone may support migratory activity through a receptor other than the GR. Energy metabolism (as determined through plasma metabolites) was also unaffected by RU486, possibly because energetic demands experienced by captive birds were low.

The influence of photoperiod and temperature on the seasonal (fall to winter) cold acclimation and accu- mulation of a 25 kDa dehydrin in Rhododendron 'Chionoidesʼ was studied by exposing two groups of plants each in the greenhouse or outdoors to either a natural photoperiod (or short days) or an extended photoperiod (or long days) regime. Results suggest that the shortening daylength alone is suffi cient to trigger both the fi rst stage of cold acclima- tion and concomitant 25 kDa dehydrin induction. Exposure of the plants to natural photoperiod and temperatures induced the greatest cold hardiness and 25 kDa accumulation, while exposure to extended photoperiods (long days) and warmer temperatures (in the greenhouse) failed to induce any signifi cant freezing tolerance in leaves. Whereas short days trigger the cold acclimation process initially, low inductive temperatures can eventually replace the photoperiod stimulus. Seasonal accumulation of 25 kDa dehydrin, on the other hand, appears to be predominantly effected by short photoperiods. Data indicated that the leaf water content of outdoor plants maintained under natural photoperiod was lower than that of plants grown under extended photoperiod. This was also true for the greenhouse plants at the fi rst (September) and the last (January) sampling. It is hypothesized that early 25 kDa dehydrin accumulation may be due to short-day-induced cellular dehydration. Accumulation of two other dehydrins of 26 kDa and 32 kDa molecular masses does not appear to be associated with short day (SD)-induced fi rst stage of cold acclimation. Results show that their accumulation may be regulated by low, subfreezing temperatures and may be associated with the second and/or third stage of cold acclimation of 'Chionoidesʼ rhododendron leaves. Freezing temperatures constitute one of the major environmen- tal constraints limiting growth, development, and distribution of plants. Most tropical and subtropical plant species and herbaceous annuals lack the ability to adapt to cold winters and are typically injured or killed by slightly subfreezing temperatures. In contrast

The onset of mating in yellow-pine chipmunks (Tamias amoenus) follows emergence from a prolonged period of energy conservation during hibernation. Energy expenditures are greatly accelerated to meet the demands of the reproductive season. When emerging from hibernation, typical male chipmunks (breeders) have enlarged testes and a high level of plasma testosterone M. However, certain males that do not participate in reproduction (nonbreeders) maintain small testes and low plasma T levels and emerge several weeks later than the breeders. The timing of the terminal arousal from hibernation and onset of mating are associated with increased plasma T levels. Experimental elevation of T levels in T amoenus outside the mating season has been associated with a decrease in body mass, further suggesting an effect of T on energy balance. To test this hypothesis, we measured daily energy expenditure (DEE) in free-living, nonbreeding male chipmunks in the presence and absence of a T-implant. We also measured DEE in breeding males when endogenous T levels were high. DEE of the nonbreeders was not affected by our manipulation of plasma T, and the DEE of breeding males did not differ from that of nonbreeders. We conclude that energy expenditure on a daily basis in male yellow-pine chipmunks is not influenced by levels of T. However, on a seasonal basis, the earlier emergence from hibernation by breeding males, which appears to be influenced by T, represents an overall seasonal energy expenditure that exceeds that of nonbreeding males. J. Exp. Zool. 292:460-467, 2002. (C) 2002 Wiley-Liss, Inc.