Varying endophyte status and energy supplementation of fresh tall fescue in continuous culture

Eight dual-flow continuous culture vessels (700 ml) were used to compare in vitro effects of toxic, endophyte-infected (E+), endophyte-free (E−), and non-toxic, endophyte-infected (EN) Jesup tall fescue (vegetative stage) on ruminal fermentation at 4 levels (0, 150, 300, and 450 g kg⁻¹ DM) of concentrate supplementation (ground corn) for a total of 12 experimental diets in a randomized incomplete block design with 2 replicates. Each culture vessel was offered a total of 15 g DM d⁻¹. Forage was fed in four equal portions (fed at 03:00, 09:00, 15:00, and 21:00 h); and corn was fed in two equal portions (fed at 09:00 and 21:00 h). Headspace gas and liquid samples were analyzed for methane, ruminal culture pH, ammonia–N, and volatile fatty acid production. Ammonia–N output (g d⁻¹) varied by grass; EN had lower values compared to those of E+ and E−. Increasing the level of grain linearly decreased ruminal culture pH, ammonia–N, acetate production, and the acetate-to-propionate ratio, whereas propionate and butyrate production increased with higher grain supplementation. Ruminal fermentation was minimally altered by the presence of the endophyte; however, for the highest level of grain fed (450 g kg⁻¹ DM fed) the methane production pattern for all three grasses was altered. In addition to having the lowest ruminal ammonia–N accumulation, the non-toxic, endophyte-infected fescue resulted in the lowest methane production measured.     

How to efficiently obtain accurate estimates of flower visitation rates by pollinators

Regional declines in insect pollinators have raised concerns about crop pollination. Many pollinator studies use visitation rate (pollinators/time) as a proxy for the quality of crop pollination. Visitation rate estimates are based on observation durations that vary significantly between studies. How observation duration relates to the accuracy of the visitation rate estimate is, however, unknown. We studied this relationship using six day-long observations (06:00 h–19:00 h) in leek-seed production fields (totalling 78 h). We analysed beyond which point in time observing longer did not significantly improve the accuracy of the visitation rate estimate (minimum observation duration). We furthermore explored the relationship between the minimum observation duration and visitation rate, time of day and temperature. We found that the minimum observation duration (mean ± SD: 24 ± 11.9 min) was significantly related to visitation rate, where the observation time required to obtain accurate estimates decreased with increasing visitation rate. Minimum observation duration varied greatly between days and between fields but not within days. Within days, the visitation rates differed significantly only between the hour-intervals 06:00 h–07:00 h (lowest visitation rate) and 09:00 h–11:00 h (highest rate). Minimum observation duration decreased up to around 22 °C beyond which it remained fairly stable. Surprisingly, even after three day-long observations on the same plant we found new pollinator species visiting the flowers, suggesting that species-richness estimates based on plant observations alone probably underestimate true species richness. Because especially between-day variation in visitation rate on single plants can be large, reliable estimates of the pollinator visitation rate during the plant’s flowering time require observations on multiple days. Standardising the number of pollinators rather than the time to observe (standardised pollinator timing approach: time to n-pollinator visits) may provide more consistent accurate assessments of visitation rate, especially for studies that use gradients in visitation rates to examine the contribution of pollinators to crop pollination.     

Growth of dinoflagellates,Ceratium furca and Ceratium fusus in Sagami Bay,Japan: The role of vertical migration and cell division

To better understand the mechanism underlying the bloom outbreaks of dinoflagellates, Ceratium furca, and Ceratium fusus in the temperate coastal area of Sagami Bay, we investigated the diel changes of vertical migration, swimming speed, cell volume, and cell division. Our results from both the field and laboratory indicate that C. furca and C. fusus can migrate vertically between surface and sub-surface layers to avoid strong sunlight (>1000 μmol m⁻² s⁻¹). Diel vertical migration (DVM) of C. furca was observed in the laboratory, while that of C. fusus was not observed. C. furca demonstrated a constant DVM rhythm, i.e., their cells began to descend from the surface before the light was extinguished, and ascended into the surface before the light was turned on. The downward and upward migrations of the cells occurred at every 3 h before turning on and off the light, suggesting that the DVM pattern was independent of nutrient concentration. The swimming speeds of C. furca (avg. 250 μm s⁻¹) were always faster than those of C. fusus (avg. 75 μm s⁻¹). In addition, the speeds of C. furca during light periods were faster than those during dark periods, whereas the speeds of C. fusus remained relatively constant. A higher proportion of dividing cells was recorded near dawn (05:00–07:00 h). Cell volumes of C. furca and C. fusus did not markedly change between 12:00 and 21:00 h, but gradually increased until 03:00 h and then sharply decreased. Furthermore, the cell volume of the two Ceratium species was significantly shifted to the temporal pattern of cell division. Combined with the DVM manner of two Ceratium and cell division timing, only C. furca divided at the bottom, and then moved toward the surface shortly before the dark to light transition. Based on our observations, C. furca has an ecological advantage due to their DVM activity, since nutrients can be obtained well in the near bottom layers, while during the daytime, light present in nutrient-depleted surface water can be obtained using their high swimming speed. On the other hand, C. fusus stimulated by low salinity conditions, might be dependent on external environmental conditions such as additional nutrients following freshwater discharge by heavy rainfall because they may not perform active DVM due to a slow swimming ability. Our findings support that specific characteristics, including the DVM behavior in C. furca, yield a competitive advantage over C. fusus in Sagami Bay.     

Vertical habitat segregation as a mechanism for coexistence in sympatric rodents

Coexistence has been widely studied in small mammals and frequently is assumed to be facilitated by habitat segregation. Using live trapping and spool-and-line experiments, we analyzed habitat selection and segregation across multiples scales for Peromyscus leucopus and Ochrotomys nuttalli. At the habitat scale of a forest stand (∼1–100s ha) P. leucopus co-occurred at all sites where O. nuttalli was found, and we did not detect evidence of positive or negative associations or habitat segregation. However, O. nuttalli was restricted to early successional forests, and P. leucopus had significantly lower abundances in early successional forests than in other habitats. We found similar patterns at the mesohabitat scale of the study site (400 m²). O. nuttalli abundance increased with increasing shrub and tree densities, while increases in P. leucopus abundance were associated with open understories. At the microhabitat scale of the individual movement trail, we found vertical segregation. Movement trails for O. nuttalli were at significantly higher elevation (mean height = 142.93 ± 37.10 cm) than P. leucopus trails (mean height = 15.4 ± 4.98 cm; F-value = 35.29, p < 0.001). We concluded that microhabitat segregation was driven by differential use of vertical space for movement and foraging. We suggest O. nuttalli is superior to P. leucopus in its ability to acquire food especially in shrubby subcanopies where few acorns are available. However, P. leucopus is superior in its ability to forage and avoid predators.     

Determinants of smooth-coated otter occupancy in a rapidly urbanizing coastal landscape in Southeast Asia

Urbanization often has negative impacts on wildlife, nevertheless many species can persist in heavily modified habitats. Understanding factors that promote species persistence in urbanizing landscapes is therefore important for maintaining biodiversity in changing landscapes and may inform more biodiversity-friendly development. We investigated effects of landscape-scale variables on habitat occupancy of Smooth-coated otter (Lutrogale perspicillata) in the Inner Gulf of Thailand. In this internationally important wetland complex, 86% of natural habitats have been altered and are now highly urbanized. We conducted track and sign surveys in 60, 25 km² grid cells encompassing 1,474 km². Within each cell, we quantified the landscape cover types including urban areas, natural habitat (predominately thin ribbons of mangrove along waterways), agriculture, aquaculture, and potential prey availability using a GIS and field surveys. We used occupancy models to identify habitat variables that affected probability of detection and occupancy. Estimated otter occupancy, based on the top model, was 0.33 ± 0.07 (95% CI 0.18–0.48) and detection probability was 0.50 ± 0.05 (95% CI 0.41–0.60). Otter occupancy was positively associated with the proportion of natural habitat and the cover of traditional aquaculture ponds, but negatively associated with agriculture and urban cover. The remaining natural patches appear to act as critical refuges for otter, allowing them to persist in an otherwise heavily transformed landscape. Because aquaculture ponds are likely important prey sources for otters, it may lead to conflict with aquaculture farmers. Further studies of feeding and movement patterns in cooperation with aquaculture farmers would be beneficial for developing detailed management plans for the species in this human dominated landscape.     

Monitoring of aquatic macroinvertebrates as bioindicator for assessing the health of wetlands: A case study in the Central Himalayas,India

The present contribution encompasses the first case study on the aquatic macroinvertebrates as bioindicators for assessing the health of Asan wetland (area 3.2 km²), located in the foothills of Central Himalayas, India. Monthly sampling from all the sampling sites in five replicates was made for a period of 12 months (July 2002–June 2003) at 9:00–11:00 h. A total of 32 species of macroinvertebrates were found with the Ephemeroptera and Gastropoda being the most abundant component of invertebrates communities. The Shannon–Wiener diversity index calculated for macroinvertebrates ranged from 3.50 to 4.61. Seasonal fluctuations in the density of macroinvertebrates revealed maximum density (451–503 ind m^?2) during winter and minimum (126–143 ind m^?2) during monsoon season. The density of macroinvertebrates was influenced by the anthropogenic disturbances and water level fluctuations causing disturbance in the littoral zone of the wetland. The statistical relationships between turbidity, transparency, dissolved oxygen and water temperature and macroinvertebrates of Asan wetland were also computed for assessing the impact of anthropogenic disturbances on macroinvertebrates.     

Analysis of the germination rate,mitotic index and karyotype of Chromolaena barranquillensis (Hieron.) R.M. King & H. Rob.—Asteraceae

Chromolaena barranquillensis (Asteraceae) is an endemic plant of northern Colombia that has garnered economic and medicinal interest, because species from the genus Chromolaena have shown diverse biological activities. This study describes, for the first time, the karyotype, germination and mitotic indices of C. barranquillensis (Hieron.) R.M. King & H. Rob. The germination index was between 34% and 56% with an average germination rate of 1.2 ± 0.4 seeds/day. The mitotic index analysis allowed to determine the cell cycle time (4 h, 10 min) and the mitotic hours (3:00–8:00 h and 17:00 h). The mitosis time was 49 min, equivalent to ~ 20% of the cell cycle. Karyotype analysis showed that C. barranquillensis is a hexaploid species with a chromosomal formula 2n = 6x = 60 = 48 m + 12 sm, and the average chromosomal lengths were 1.7 ± 0.1 μm to 0.9 ± 0.3 μm. The Stebbins asymmetry index was 2B, and the total form percentage was ~ 41%. These results uncover differences between C. barranquillensis and Chromolaena odorata, one of the most abundant species found in the world and the most closely related species to C. barranquillensis.     

Temperature selection by juvenile tuatara (Sphenodon punctatus) is not influenced by temperatures experienced as embryos

Most reptiles thermoregulate to achieve body temperatures needed for biological processes, such as digestion and growth. Temperatures experienced during embryogenesis may also influence post-hatching growth rate, potentially through influencing post-hatching choice of temperatures. We investigated in laboratory settings whether embryonic temperatures (constant 18 °C, 21 °C and 22 °C) influence selected body temperatures (T_sel) of juvenile tuatara (Sphenodon punctatus), providing a possible mechanism for differences in growth rates. We found that incubation temperature does not influence T_sel. Although the average daily mean T_sel was 21.6 ± 0.3 °C, we recorded individual T_sel values up to 33.5 °C in juvenile tuatara, which is higher than expected and above the panting threshold of 31–33 °C reported for adults. We found diel patterns of T_sel of juvenile tuatara, observing a general pattern of two apparent peaks and troughs per day, with T_sel being significantly lower around dawn and at 1500 h than any other time. When comparing our results with other studies on tuatara there is a remarkable consistency in mean T_sel of ~ 21 °C across tuatara of different ages, sizes and acclimatization histories. The ability of juvenile tuatara to withstand a wide range of temperatures supports their former widespread distribution throughout New Zealand and warrants further investigation into their plasticity to withstand climate warming, particularly where they have choices of habitat and the ability to thermoregulate.     

Shape complexity of space used by American black bears influenced by sex and intensity of use

Disentangling the complexities that influence animal space use poses substantial challenges based on decision trade-offs and constraints imposed on animals. Optimal decisions suggest that the spatial complexity of home-range shapes should be inversely related to energy conservation and fitness. Hence, the most beneficial shape should be the circle. We evaluated whether shape complexity (i.e., an index of circularity) of home ranges was influenced by two extrinsic (spatial heterogeneity, preferred habitat [i.e., deciduous forest]), and three intrinsic (sex, season [breeding, non-breeding], intensity of use) factors, with intensity of use indexed as contours containing core and peripheral areas. We estimated utilization distributions of 39 radiomarked adult American black bears (Ursus americanus), a habitat generalist, using fixed-kernel techniques and estimated 50% (core area) and 95% (peripheral area) contours. We fit a set of 47 models using linear modeling and ranked models using small-sample Akaike Information Criterion. Coefficients for the best model were the intrinsic factors intensity of use (reference category = core; 0.118; 95% CL = 0.064–0.173), sex (reference = female; 0.105; 95% CL = 0.043–0.167), and intercept (0.229; 95% CL = 0.186–0.272). Shape complexity was less for core areas than peripheral areas and less for females than males. Considering complex resource selection patterns within a fragmented landscape, both sexes appeared to use energy-maximizing strategies, although the increase in shape complexity for males may be an allometric relationship based on size dimorphism. Our approach supported the phenomenon of optimality as manifested through home-range shape complexity, but we suggest that assessment of this phenomenon for habitat specialists may yield different results, including the potential importance of intrinsic factors based on more restrictive limiting factors.     

Neuromuscular control of scapula muscles during a voluntary task in subjects with Subacromial Impingement Syndrome. A case-control study

Imbalance of neuromuscular activity in the scapula stabilizers in subjects with Subacromial Impingement Syndrome (SIS) is described in restricted tasks and specific populations. Our aim was to compare the scapular muscle activity during a voluntary movement task in a general population with and without SIS (n = 16, No-SIS = 15).Surface electromyography was measured from Serratus anterior (SA) and Trapezius during bilateral arm elevation (no-load, 1 kg, 3 kg). Mean relative muscle activity was calculated for SA and the upper (UT) and lower part of trapezius (LWT), in addition to activation ratio and time to activity onset. In spite of a tendency to higher activity among SIS 0.10–0.30 between-group differences were not significant neither in ratio of muscle activation 0.80–0.98 nor time to activity onset 0.53–0.98.The hypothesized between-group differences in neuromuscular activity of Trapezius and Serratus was not confirmed. The tendency to a higher relative muscle activity in SIS could be due to a pain-related increase in co-activation or a decrease in maximal activation. The negative findings may display the variation in the specific muscle activation patterns depending on the criteria used to define the population of impingement patients, as well as the methodological procedure being used, and the shoulder movement investigated.     

Genotoxicity evaluation of the insecticide imidacloprid on circulating blood cells of Montevideo tree frog Hypsiboas pulchellus tadpoles (Anura,Hylidae) by comet and micronucleus bioassays

Acute toxicity and genotoxicity of imidacloprid (IMI) was evaluated on Hypsiboas pulchellus (Anura: Hylidae) tadpoles exposed under laboratory conditions. A lethal effect was used as the end point for lethality, whereas the frequency of micronuclei (MNs) and DNA single-strand breaks evaluated by the single cell gel electrophoresis assay were employed as end points for genotoxicity. Experiments were performed on tadpoles at stage 36 (range, 35–37) according to the classification proposed by Gosner. Mortality studies revealed an LC₅₀ (96 h) value of 84.91 mg/L IMI (95% confidence limits, 77.20–93.04). While increased frequency of MNs was observed when 15 and 30 mg/L were assayed for 48 h, only 15 mg/L increased the frequency of MNs in tadpoles exposed for 96 h. Furthermore, other nuclear abnormalities, i.e., binucleated cells and blebbed and notched nuclei, were induced in tadpoles exposed for both 48 h when treated with 15 mg/L and 96 h when treated with 15 and 30 mg/L. An increase in the genetic damage index was observed in tadpoles treated with 30 mg/L for 48 and 96 h. This study represents the first evidence of acute lethal and sublethal effects exerted by IMI on tadpoles of an amphibian species native to Argentina. Finally, our findings highlight the hazardous properties of this insecticide for nontarget living species exposed to this agrochemical.     

Feeding behaviour and caecotrophy in the young rabbit before weaning: An approach by analysing the digestive contents

Young rabbits consume milk, feed and soft faeces during the pre-weaning period, but the biological rhythm of intake were scarcely described. This work aimed to analyse the behaviour of ingestion and caecotrophy by analysing the stomach and rectal contents of young rabbits. Chronological samplings were performed according to a 4 × 3 factorial experimental design (17, 22, 28 and 35 days at 3, 8 and 23 h after suckling, respectively). Both digestive contents were examined and scored according to a discrete 4-step scale. Milk intake peaked around 22 days (26.6 g/rabbit) and decreased by 50% at 28 days. Stomach score for milk content showed a negative relationship with age. Dry feed intake reached 7.2 g/rabbit at 22 days, but was relatively variable among litters (CV = 44%). After 22 days, nutrient intake from the solid feed exceeded that of the milk. A higher pellet intake was observed during the night period (18:00–09:00 h) whatever the age. Dry feed in the stomach content was affected by age (17 versus 22, 28 and 35 days). From 22 days, milk and feed components were particularly distributed in the stomach: the coagulated milk was close to the wall of the fundus, whereas the feed was homogeneously spread. Soft faeces were not found until 28 days of age, and were located in the fundic region (25–30% of stomach profile). Stomach weight increased almost threefold from 17 to 35 days of age, but showed a slower development than the rest of the body from 22 to 35 days (relative stomach weight from 1.65 to 1.38%). High pH values (5.5–3.0) were found in the fundus at 3 and 8 hours after suckling. The pH in the antrum decreased from 4.19 to 1.90 at 17 and 22 days, respectively. The excretion of hard and soft faeces was indirectly recorded by checking the content of distal colon and rectum. From 22 days onwards, the amount of hard faeces in distal colon and rectum reached a peak at 8 h after suckling (2.3 ± 0.2). On the contrary, soft faeces were only observed at 3 and 23 h after suckling from 28 days of age.     

Effect of thermal exposure on physiological adaptability and seminal attributes of rams under semi-arid environment

Thermal stress in hot semi-arid environment is a major limitation of sheep production in tropical and sub-tropical climatic condition. The animals tend to maintain homeostasis through physiological adjustments in a hot environment (maximum temperature reaches up to 47.5 °C). Therefore, the present study was carried out to assess the effect of thermal exposure on physiological adaptability and seminal attributes of rams under semi-arid environment. The experiment was conducted for eight weeks involving sixteen Malpura crossbred rams (GMM: Garole X Malpura X Malpura). The rams were divided equally into two groups, designated as G1 and G2, respectively. The rams in G1 (Control) group were kept in a sheep shed under naturally prevailing environment without artificial manipulation of ambient temperature (Temperature 30.48±0.38 °C; Relative Humidity 28.59±1.15%). The rams of G2 group were exposed to different temperature at different hours of the day (38 °C at 1000–1100 h; 40 °C at 1100–1200 h; 42 °C at 12:00–1300 h; 43 °C at 1300–1400 h; 44 °C at 1400–1500 h and 42 °C at 1500–1600 h) in a climatic chamber for thermal exposure. Physiological responses, blood biochemical profile, blood endocrine profile, sexual behavior and seminal attributes were measured for both the groups. Thermal exposure significantly (P<0.05) increased the water intake; respiration rate, rectal temperature and skin temperature at afternoon in rams. Exposure of rams to thermal stress (G2) significantly (P<0.05) increased cortisol level and decreased tri-ido-thyronine level. The latency period after the first ejaculation, decreased significantly (P<0.05) in G2. The percentage of rapid motile sperm, linearity and average path velocity of sperm were also altered significantly (P<0.05) in thermal exposed rams as compared to control. However, comparable feed intake, body weight, and major blood biochemical parameters, as well as acceptable semen quality attributes of all the rams indicated that the Fec B gene introgressed Malpura cross rams adapted to the thermal exposure under semi-arid tropical climate.     

Supplemental energy and protein increase use of sagebrush by sheep

The ability of sheep to consume big sagebrush (Artemisia tridentata Nutt.), a shrub that contains terpenes, may be improved with supplemental energy and protein needed for detoxification processes. We compared feeding behavior of supplemented and unsupplemented ewes grazing separately in three 0.5 ha plots of 40 m × 120 m during October 2001. Supplemented ewes were offered a choice of a high-energy (50% corn and 50% beet pulp—3.62 Mcal/kg DE and 9.5% CP) and a high-protein (85% alfalfa and 15% soybean meal—2.89 Mcal/kg DE and 15% CP) supplement for 15 min/day. Supplemented ewes consumed 492 g (S.E. = 24.3) of the high-energy supplement and 140 g (S.E. = 9.8) of the high-protein supplement. The incidence of feeding on sagebrush was recorded using scan sampling at 10-min intervals from 09:00 to 17:00 h every other day for 10 days. Incidence of feeding on sagebrush increased gradually for both treatments from 0.4% on day 1 to 28% on day 10 (P < 0.01), but supplemented ewes increased feeding frequency on sagebrush to nearly twice that of unsupplemented ewes by the end of the trial. Averaged throughout the trial, incidence of eating sagebrush was twice as high for supplemented compared to unsupplemented ewes (22% versus 11% of the total time feeding, P < 0.01). The results of this study show that supplemental macronutrients increase use of sagebrush by ewes. Thus, strategic supplementation during fall and winter may be a way to increase intake of sagebrush by sheep and enhance and maintain biodiversity in areas of the sagebrush steppe where sagebrush is deemed too abundant.     

How far can a tortoise walk in open habitat before overheating? Implications for conservation

Terrestrial chelonians are threatened worldwide by habitat destruction and illegal harvesting. Tortoises are slow moving animals susceptible to dehydration and overheating during movements in open habitats. Many species inhabit arid steppes where the availability of thermally buffered refuges (e.g. burrows) is a limiting factor. Determining the maximal distance between refuges that individuals can safely traverse during the active season is thus essential. We examined the relationship between body temperature variations and movement patterns in adult Testudo graeca in the arid steppes of Morocco. Using physical and mathematical models, our results suggest that during the active season adults cannot travel more than 1 km without serious risk of overheating. However, radio-tracking suggests that free-ranging individuals are behaviourally limited to 0.5 km trips between refuges. Overall, maintaining a distance less than 0.5 km between refuges (e.g. through bush planting) is essential to limit fragmentation and to retain healthy populations. This restoration would also benefit to many other species that depend on bush-refuges.     

A potent and selective inhibitor targeting human and murine 12/15-LOX

Human reticulocyte 12/15-lipoxygenase (h12/15-LOX) is a lipid-oxidizing enzyme that can directly oxidize lipid membranes in the absence of a phospholipase, leading to a direct attack on organelles, such as the mitochondria. This cytotoxic activity of h12/15-LOX is up-regulated in neurons and endothelial cells after a stroke and thought to contribute to both neuronal cell death and blood–brain barrier leakage. The discovery of inhibitors that selectively target recombinant h12/15-LOX in vitro, as well as possessing activity against the murine ortholog ex vivo, could potentially support a novel therapeutic strategy for the treatment of stroke. Herein, we report a new family of inhibitors discovered in a High Throughput Screen (HTS) that are selective and potent against recombinant h12/15-LOX and cellular mouse 12/15-LOX (m12/15-LOX). MLS000099089 (compound 99089), the parent molecule, exhibits an IC₅₀ potency of 3.4 ± 0.5 μM against h12/15-LOX in vitro and an ex vivo IC₅₀ potency of approximately 10 μM in a mouse neuronal cell line, HT-22. Compound 99089 displays greater than 30-fold selectivity versus h5-LOX and COX-2, 15-fold versus h15-LOX-2 and 10-fold versus h12-LOX, when tested at 20 μM inhibitor concentration. Steady-state inhibition kinetics reveals that the mode of inhibition of 99089 against h12/15-LOX is that of a mixed inhibitor with a K_ic of 1.0 ± 0.08 μM and a K_iu of 6.0 ± 3.3 μM. These data indicate that 99089 and related derivatives may serve as a starting point for the development of anti-stroke therapeutics due to their ability to selectively target h12/15-LOX in vitro and m12/15-LOX ex vivo.     

Spatial requirements of jaguars and pumas in Southern Mexico

Understanding how large felids use space is essential for the design of conservation plans that are required for their survival. Jaguars (Panthera onca) and pumas (Puma concolor) are the largest felids in the Neotropics, and they are sympatric throughout the entire range of the jaguar. However, there is very little information about the spatial requirements of these two species in the tropical rainforests of Central America. Using satellite GPS collars, we compared the spatial ecology of jaguars and pumas in a tropical rainforest in southern Mexico. We found that jaguars had home ranges that were 2–6 times larger than those of pumas. The mean annual home range was 181.4 ± 4.0 km² for female jaguars and 431.6 ± 152.6 km² for males. Annual home range for the only female puma tracked was 34.3 km², and 72.0 ± 85.2 km² for males. Jaguars and pumas with overlapping home ranges showed little overlap of core areas and avoided using the same sites at the same time, which suggested that territoriality and avoidance were in play. Further evidence of avoidance was derived from our observation that pumas exhibited greater movement during the lightest periods of the day and jaguars moved most during the darkest. This temporal separation probably facilitates coexistence. Our data suggest that habitat destruction and fragmentation has more severe effects on jaguars than on pumas. According to our estimates, patches of at least 180 km² of primary forest are required to meet the annual spatial requirements of female jaguars. Thus, to conserve jaguars in this region, large tracts of primary forest should be preserved. Importantly, this population of jaguars depends on the adequate preservation of connectivity between natural reserves in Mexico and Guatemala.     

Physiological responses of Corythucha ciliata adults to high temperatures under laboratory and field conditions

Under high temperature conditions, insects can tolerate to survive through various physiological mechanisms, which have been well documented in laboratory studies. However, it is still unclear as to whether these laboratory data can scale up to those in the field. Here we studied dynamics of heat-induced metabolites in Corythucha ciliata adults under both laboratory and field conditions to examine their significance in thermal tolerance of the species. We compared the effects of controlled thermal treatments (2 h at 33–43 °C at 2 °C intervals in the laboratory) and naturally increasing thermal conditions (10:00–14:00 at 2-h intervals (33.5–37.2 °C) on a hot summer day in a field in Shanghai, China) on water content and levels of water-soluble protein, triglycerides, mannitol, and sorbitol in the adult bodies. The results showed that water content significantly decreased and all other metabolic parameters significantly increased in response to temperature stresses with similar patterns in both the laboratory and field, although the respective threshold temperatures were different under the two conditions. The close linkage observed in the two conditions suggests that a short period of heat stress induces water loss and accumulation of thermal metabolites in C. ciliata adults. This heat-resistance provides a defense mechanism counteracting thermal damage in C. ciliata.     

Quantifying ‘normal’ shoulder muscle activity during abduction

The purpose of this experiment was to obtain electromyographic (EMG) activity from a sample of healthy shoulders to allow a reference database to be developed and used for comparison with pathological shoulders. Temporal and intensity shoulder muscle activation characteristics during a coronal plane abduction/adduction movement were evaluated in the dominant healthy shoulder of 24 subjects. Surface and intramuscular fine wire electrodes recorded EMG activity from 15 shoulder muscles (deltoid × 3, trapezius × 3, subscapularis × 2, latissimus dorsi, pectoralis major, pectoralis minor, supraspinatus, infraspinatus, serratus anterior and rhomboids) at 2000 Hz for 10 s whilst each subject performed 10 dynamic coronal plane abduction/adduction movements from 0° to 166° to 0° with a light dumbbell. Results revealed that supraspinatus (?.102 s before movement onset) initiated the movement with middle trapezius (?.019 s) and middle deltoid (?.014 s) also activated before the movement onset. Similar patterns were also found in the time of peak amplitude and %MVC with a pattern emerging where the prime movers (supraspinatus and middle deltoid) were among the first to reach peak amplitude or display the highest %MVC values. In conclusion, the most reproducible patterns of activation arose from the more prime mover muscle sites in all EMG variables analysed and although variability was present, there emerged ‘invariant characteristics’ that were considered ‘normal’ for this group of non pathological shoulders. The authors believe that the methodology and certain parts of the analysis in this study can be duplicated and used by future researchers who require a reference database of muscle activity for use as a control group in comparisons to their respective pathological shoulder group.     

Disturbed motor control of rhythmic movement at 2 h and delayed after maximal eccentric actions

The aim of this study was to examine the influence of exercise-induced muscle damage on elbow rhythmic movement (RM) performance and neural activity pattern and to investigate whether this influence is joint angle specific. Ten males performed an exercise of 50 maximal eccentric elbow flexions in isokinetic machine with duty cycle of 1:15. Maximal dynamic and isometric force tests (90°, 110° and 130° elbow angle) and both active and passive stretch reflex tests of elbow flexors were applied to the elbow joint. The intentional RM was performed in the horizontal plane at elbow angles; 60–120° (SA-RM), 80–140° (MA-RM) and 100–160° (LA-RM). All measurements together with the determination of muscle soreness, swelling, passive stiffness, serum creatine kinase were conducted before, immediately and 2 h as well as 2 days, 4 days, 6 days and 8 days post-exercise. Repeated maximal eccentric actions modified the RM trajectory symmetry acutely (SA-RM) and delayed (SA/MA/LA-RM) until the entire follow up of 8 days. Acutely lowered MA-RM peak velocity together with reduced activity of biceps brachii (BB) at every RM range, reflected a poorer acceleration and deceleration capacity of elbow flexors. A large acute drop of BB EMG burst amplitude together with parallel decrease in BB active stretch reflex amplitude, especially 2 h post-exercise, suggested an inhibitory effect originating most likely from groups III/IV mechano-nociceptors.