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Botryosphaeria branch canker and dieback of avocado (Persea americana Mill.) has expanded in avocado-growing areas in recent years. Twenty-one avocado groves in the major producing regions of California were surveyed in 2018 and 2019. Monthly inoculations of wounded, green, and lignified branches of ‘Hass’ and ‘Lamb Hass’ were conducted. Botryosphaeriaceae were the predominant fungi recovered from cankered tissues collected across the surveyed traditional and high-density orchards and caused symptoms on all six sampled cultivars. These fungi were also recovered in asymptomatic twigs and other organs and thus exist as a potential reservoir for future infections. Molecular analyses of 173 isolates showed that Neofusicoccum luteum had the greatest incidences across sites and cultivars, with 83 and 29% recovered from Hass and Lamb Hass, respectively. Pathogenicity tests on excised (Hass, GEM, and Hass mutants) and attached shoots from potted (Hass) and mature avocado trees (Hass and Lamb Hass) showed that all species were pathogenic on wounded, green, and mature branches of the specified cultivars. Monthly inoculations of wounded, green, and lignified branches of Hass and Lamb Hass showed that both stem types were susceptible throughout the inoculation periods, regardless of the avocado phenological stage. In temperature-dependent growth and infection studies, growth of three points could vary during the growing season. Botryosphaeriaceae grown was higher between 20 and 30°C, but only Lasiodiplodia theobromae significantly grew and caused external lesions at 35°C. Lasiodiplodia theobromae also grew more on perseitol-amended media, all indicating its adaptation to warmer temperatures and capacity in metabolizing the avocado-produced sugar. Overall, this study extended our knowledge of the prevalence, identity, and pathogenicity of Botryosphaeriaceae on avocado cultivars, which will be useful to tailor management strategies. [ABSTRACT FROM AUTHOR]

Heat stress has negative consequences for milk production and reproduction of dairy cattle. These adverse effects are likely to increase because of climate change and anticipated increases in milk yield. Some of the variation among cows in ability to resist effects of heat stress is genetic. The current objective of this observational study was to assess the effectiveness of the Australian breeding value for heat tolerance (ABVHT) based on the decline in milk yield with heat stress for predicting cow differences in effects of heat stress on regulation of body temperature, milk production, and reproductive function. Genomic breeding values for heat tolerance were calculated for 12,487 cows from a single California dairy farm. Rectal temperature in the afternoon (1100–2045 h) was measured on a subset of 626 lactating cows with ABVHT ≥102 (heat tolerant) or <102 (heat sensitive). Rectal temperature was 0.12°C lower for heat-tolerant cows than heat-sensitive cows. Vaginal temperatures were measured every 15 min for 5 d in 118 cows with ABVHT ≥108 (extreme heat tolerant) or <97 (extreme heat sensitive). Vaginal temperature was 0.07°C lower for extreme heat–tolerant cows than extreme heat–sensitive cows. Lactation records for 4,703 cows with ABVHT were used to evaluate seasonal variation in first 90-d milk yield, fat percent, and protein percent for each ABVHT quartile. Overall, cows with higher ABVHT had lower milk yield, fat percentage, and protein percentage and higher first service pregnancy rate. There was no summer depression in production or reproduction or interactions between season and ABVHT quartile. We observed that ABVHT can successfully identify heat-tolerant cows that maintain lower body temperatures during heat stress. The lack of a pronounced seasonality in milk production or reproduction precluded evaluation of whether ABVHT is related to the magnitude of effect of heat stress on those traits. [ABSTRACT FROM AUTHOR]

Abstract: This study aims at comparing the predictions of skin temperature from different models of human thermoregulation and investigating the currently available methods for the prediction of the local and overall thermal sensations. In this paper, the Fiala model, the University of California, Berkeley (UCB) thermoregulation model and a multi-segmental (MS) Pierce model were tested against recently measured data from the literature. The local and overall thermal sensations were predicted for different room conditions, obtained from a recent experimental study, using the UCB comfort model coupled with the MS-Pierce model. The overall thermal sensation was further predicted using three other models. The predictions were then compared with the subjective votes obtained from that study. The equivalent temperature approach was also investigated based on the same experimental study. The results show comparisons of the predicted skin temperature by the thermoregulation models, under steady state and dynamic conditions, with the measured data as well as the predictions of the thermal sensations from the different models. [Copyright &y& Elsevier]

Abstract: The Mediterranean blue mussel, Mytilus galloprovincialis, is an invasive species that has displaced a congener, Mytilus trossulus, from its native range in central and southern California, USA. The dynamic relationship between interspecies competition and species-specific tolerances to abiotic factors, such as temperature and salinity, appears to have facilitated the success but has also imposed limits on the spread of this biological invasion. Here, we review the literature and present new data that document physiological differences between M. galloprovincialis and M. trossulus. In all comparisons, M. galloprovincialis is more warm-adapted than M. trossulus. Higher activities of enzymes involved in ATP generation show that the native M. trossulus is better adapted to colder conditions than M. galloprovincialis. Higher metabolic capacity (temperature compensation) in the native species may, however, lead to higher metabolic costs at sites where the two species co-occur. In addition, M. trossulus has a lower thermal tolerance of cardiac function and substrate binding by enzymes than M. galloprovincialis. The higher thermal tolerance of the invasive species is likely due in part to its enhanced ability to induce changes in the expression of particular genes and proteins in response to acute heat stress. Taken together, these data predict that M. galloprovincialis will continue to be the dominant blue mussel species along the warmer range of the California Current. Because the northern biogeographic limit of M. galloprovincialis is not stable, but rather shifts to lower or higher latitudes in concert with oceanographic variability, it is important to further characterize the physiological constraints of M. galloprovincialis, related to its sensitivity to cold temperatures and low salinities. [Copyright &y& Elsevier]

Background: T'ai chi chuan, the ancient Chinese martial art, is practiced by millions of people worldwide and is an activity of moderate intensity that involves slow, circular movements. Evidence of substantial health benefits of t'ai chi chuan is emerging, however, the physiologic mechanisms are not well-understood. T'ai chi chuan masters routinely report sensing qi or internal energy flow, particularly in the hands. The purpose of this case study was to determine whether physiologic responses normally associated with thermoregulation are activated during a basic t'ai chi chuan exercise. Methods: Trials consisted of three focus periods and one withdraw period (during which the subject withdrew internal energy in the hands), each followed by a rest period. Measurements included infrared-thermography (IR), thermocoupled temperature measures, and laser Doppler flowmetry. Results: Substantial increases in local palmar and face surface temperatures were observed with IR thermography during focus periods and substantial decreases were observed during the withdraw period. Fingertip surface baseline temperatures were 31.1°C for one trial, increased by 1.8°C during the focus period, and then decreased by 4.9°C during the withdraw period. A twofold increase in blood flow through fingertip regions paralleled changes in fingertip surface temperatures during focus periods. Conclusions: Changes in regional blood flow and surface temperatures closely paralleled onsets of focus, rest, and withdraw periods and appear to be volitional activations of known vasomotor mechanisms underlying non-hairy skin regions such as the hands and face. Changes in blood flow through these vascular structures are generally autonomic thermoregulatory responses, not normally under voluntary control, but may also represent a relaxation response. [ABSTRACT FROM AUTHOR]

Presents abstracts of studies on temperature regulation and fluid balance, presented at the Experimental Biology/International Union of Physiological Sciences 2005 congress held in San Diego, California. "Plasma Cytokine Response During Heat Strain Recovery in Mice," by Lisa R. Leon and Michael Blaha; "Effects of Thermal Stress on Vascular Pressures in Humans," by Craig G. Crandall, Carsten Tollund et al.; "Role of Depolarizing TRP Currents in Hypothalamic Neuronal Warm Sensitivity," by Yanmei Zhao and Jack A. Boulant.

Presents abstracts of studies on temperature adaptation and energetics presented at the Experimental Biology/International Union of Physiological Sciences 2005 congress held in San Diego, California. "The Human Physiological Response to an Exercise-Heat Stress Following a Single Acclimation Exposure," by Myra A. Nimmo, Helen C. Marshall, et al; "Effects of Warm Acclimation on Na/K-ATPase Alpha-Subunit Expression in Chloride Cells of Antarctic Fish," by Creighton Brauer, Jennifer Sanmann, et al; "The Metabolic and Biochemical Responses of a Tropical Elasmobranch to Alterations in Environmental Temperature," by Alexa Tullis, Michelle I. Baillie, et al.

The behavioral thermoregulation of the red swamp crayfish, Procambarus clarki, was investigated in its burrow environment. In the field, air and water temperatures within crayfish burrows fluctuated less compared with surface temperatures in the Mojave Desert. However, crayfish could still experience sub-optimal temperature regimes inside burrows. In the laboratory, P. clarki heated and cooled more rapidly in water than in air. In a thermal gradient, the crayfish selected a water temperature of 22 °C and avoided water temperatures above 31 °C and below 12 °C. Observations of behavior in an artificial burrow showed that P. clarki displayed three main shuttling behaviors between water and air in response to temperature. The number of bilateral emersions and emigrations, as well as the amount of time spent in air (in a 24 h period), were significantly greater at 34 °C than at 12, 16, 22 or 28 °C. This reflected an increased use of the behavioral thermoregulation at temperatures approaching the critical thermal maximum of this species. Upon migrating from 34 °C water into 38 °C air, crayfish body temperature decreased significantly. These periods of emersion were interspersed with frequent dipping in the water, allowing the crayfish to gain the benefits of evaporative cooling, without the physiological costs incurred by long-term exposure to air. [Copyright &y& Elsevier]

Hematocrit (packed cell volume, PCV) varies seasonally in some vertebrates and often differs between the sexes and among conspecific populations. The relative importance of these influences was tested with serial measurements of PCV in two Mojave Desert, California populations of the desert tortoise, Gopherus agassizii over two activity seasons, during a period with large seasonal differences in availability of food and water. PCV is the volume proportion of erythrocytes in whole blood. Previously collected data on energy expenditure, water flux, and blood chemistry were used to test the three causal hypotheses referred to as the nutritional-health, oxygen-requirement, and hydration hypotheses. Given such extreme climatic conditions, perhaps it is not surprising that dehydration and rainfall-associated rehydration were the dominant influences on PCV, as they were for osmoregulation.

We used ultrasonic telemetry to examine movement patterns of 11 bat rays, Myliobatis californica, in Tomales Bay, California. Tomales Bay is long (20 km) and narrow (1.4 km), and is hydrographically separated into outer and inner bay regions. The outer bay (the outermost 8 km) is characterized by oceanic conditions while the shallow inner bay (the innermost 12 km) features wide seasonal temperature shifts. Five rays were tracked monthly from October 1990 to November 1991 and six rays (four of which carried temperature-sensing transmitters) were tracked daily from 30 June to 16 July 1992. Mean bat ray movement rate was 8.84 m min-1 (range 4.49 to 13.40 m min-1) and was not significantly affected by size (p=0.592), tidal stage (p=0.610), or time of day (p=0.327). Movement direction was unrelated to tidal stage (p=0.472) but showed a highly significant diel pattern (p<0.001). From 2:50–14:50 h, rays moved toward the warmer and shallower inner bay, while from 14:50–2:50 h they moved toward the cooler and deeper outer bay. These telemetry data, along with known bat ray foraging patterns and respiratory temperature-sensitivity, argue for behavioral thermoregulation as the primary influence on this movement pattern. [ABSTRACT FROM AUTHOR]

Presents abstracts of studies on pyrogen sensing and suppressing, presented at the Experimental Biology/International Union of Physiological Sciences 2005 congress held in San Diego, California. "Sympathetic Premotor Neurons Mediating Febrile Responses and Thermoregulatory Functions," by Kazuhiro Nakamura, Kiyoshi Matsumura et al.; "Role of Nitric Oxide in Thermoregulation, Metabolic Rate, Mechanical Efficiency, and Running Performance Until Fatigue in Rats," by Umeko Marubayashi, Ana Cristina Rodrigues Lacerda et al.; "Brain Activation During Menopausal Hot Flashes Detected By fMRI," by Robert R. Freedman, Francis X. Graydon et al.

Background: The aim of this study was to apply both IV fluid and forced-air warming to decrease perioperative hypothermia in women undergoing cesarean delivery with spinal anesthesia. The authors hypothesize that combined-modality active warming (AW) would increase maternal temperature on arrival at the postanesthesia care unit (PACU) and decrease the incidence of maternal perioperative hypothermia (<36°C) compared with no AW., Methods: Forty-six healthy women (n = 23 per group) undergoing scheduled cesarean delivery with spinal anesthesia (10-12 mg bupivacaine + 10 μg fentanyl) were enrolled in this double-blinded, randomized controlled trial. Women were randomly assigned to receive either AW (warmed IV fluid and lower body forced-air warmer) or no warming (NW; blankets only). SpotOn Monitoring System was used to measure core temperature intraoperatively and for 1 hour postoperatively. The primary outcome measure was maternal temperature on arrival at the PACU. Secondary outcome measures included incidence of maternal perioperative hypothermia (<36°C), incidence of shivering, thermal comfort scores (0-100 scale), Apgar scores, and umbilical cord blood gas analysis., Results: Demographic, obstetric, and surgical data were similar between study groups. The AW group (35.9°C ± 0.5°C) had a significantly higher temperature on arrival at the PACU compared with the NW group (35.5°C ± 0.5°C, P = 0.006; 95% confidence interval of mean difference, 0.1°C-0.7°C). Fourteen (64%) women in the AW group and 20 (91%) in the NW group were hypothermic during the study period (P = 0.031). Median (interquartile range) thermal comfort scores were 100 (95-100) in the AW group and 90 (70-100) in the NW group (P = 0.008). There were no significant differences in the incidence of intraoperative shivering (22% in the AW and 45% in the NW groups; P = 0.11), Apgar scores, or umbilical vein blood gas values between the study groups., Conclusions: Fluid combined with forced-air warming is effective in decreasing the incidence of perioperative hypothermia and improving maternal thermal comfort. However, despite multimodal AW, the majority of women became hypothermic, and shivering was not prevented. The findings suggest that combined AW for cesarean delivery with spinal anesthesia is difficult, and only modest benefit should be expected.

Hosts and parasites form interacting populations that influence each other in multiple ways. Their dynamics can also be influenced by environmental and ecological factors. We studied host-parasite dynamics in a previously unexplored study system: side-blotched lizards and their micro-parasites. Compared with uninfected lizards, the infected lizards elected to bask at lower temperatures that were outside their range of preferred temperatures. Infected lizards also were not as precise as uninfected lizards in maintaining their body temperatures within a narrow range. At the ecological scale, areas with higher infection rates coincided with more thermally heterogeneous microhabitats as well as with the areas where lizards tended to live longer. Thermal heterogeneity of lizards' microhabitats may provide important clues to the spatial and temporal distribution of infections., (© The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.)

Temperature affects multiple aspects of an organism's biology and thus defines a major axis of the fundamental niche. For ectotherms, variation in the thermal environment is particularly important because most of these taxa have a limited capacity to thermoregulate via metabolic heat production. While temperature affects all life-history stages, stages can differ in their ability to respond to the thermal environment. For example, in oviparous organisms, free-living adults can behaviorally thermoregulate, whereas developing embryos are at the mercy of the nest environment. These differences in the realized thermal environment should select for life-history stages to have different thermal tolerances, although this has been rarely examined. I tested the hypothesis that stage-specific thermal reaction norms can evolve independently by using southern alligator lizards (Elgaria multicarinata, Anguidae). Using incubation experiments (five temperatures: 24°, 26°, 28°, 30°, and 32°C), I described the thermal reaction norm for embryonic development and compared these results to previous studies on the thermal ecology of adults. Offspring survivorship and morphology were similarly affected by incubation temperature. While developing embryos had the same optimum temperature as adults (approximately 28°C), the breadth of their thermal reaction norms differed. My results suggest that developing embryos of E. multicarinata are more sensitive to variation in the average thermal environment than are adults. Variation in the thermal sensitivity of life-history stages might be common and has implications for how organisms respond to variation in the thermal environment. Identifying those life-history stages that are most sensitive/limiting will be important for developing models that best predict species' responses to impending environmental change.

Body temperature is a more pertinent variable to physiological stress than ambient air temperature. Modeling and empirical studies on the impacts of climate change on ectotherms usually assume that body temperature within organisms is uniform. However, many ectotherms show significant within-body temperature heterogeneity. The relationship between regional heterothermy and the response of ectotherms to sublethal and lethal conditions remains underexplored. We quantified within-body thermal heterogeneity in an intertidal sea star (Pisaster ochraceus) during aerial exposure at low tide to examine the lethal and sublethal effects of temperatures of different body regions. In manipulative experiments, we measured the temperature of the arms and central disc, as well as survival and arm abscission under extreme aerial conditions. Survival was related strongly to central disc temperature. Arms were generally warmer than the central disc in individuals that survived aerial heating, but we found the reverse in those that died. When the central disc reached sublethal temperatures of 31-35°C, arms reached temperatures of 33-39°C, inducing arm abscission. The absolute temperature of individual arms was a poor predictor of arm abscission, but the arms lost were consistently the hottest at the within-individual scale. Therefore, the vital region of this sea star may remain below the lethal threshold under extreme conditions, possibly through water movement from the arms to the central disc and/or evaporative cooling, but at the cost of increased risk of arm abscission. Initiation of arm abscission seems to reflect a whole-organism response while death occurs as a result of stress acting directly on central disc tissues.

One of the proposed ecological functions of sleep is to conserve energy. The majority of studies that support this theory have been done on endothermic animals whose body temperatures drop during sleep due to the reduced neurological control of thermoregulation. In the present study, we examined typical temperatures to which the Desert Iguana, Dipsosaurus dorsalis, is exposed to in the field and found that mean high temperatures ranged from 24-58 degrees C throughout the active portion of the year. We also examined the ecological savings that sleep could provide for this ectothermic iguana using a closed system respirometer. We found that laboratory-acclimated iguanas are able to save significantly more (27.6%) energy by sleeping than by being awake and that field iguanas also had significant savings of energy (69.1%) while asleep. However, iguanas could save more energy by remaining awake at cooler temperatures than by sleeping at warmer temperatures. In addition, we found no correlation for time of night with metabolic rate. Our study supports the hypothesis that one potential function of sleep is to conserve energy.

Field metabolic rates and daily movement distances were measured in 26 individual kit foxes (Vulpes macrotis) over a 29-mo period in the southern Mojave Desert of California. Kit foxes traveled long distances (up to 32 km d(-1)), with males usually traveling farther than females. Daily movement distances were affected by season, since males traveled the greatest distances in spring and females traveled farthest in summer. Individual foxes tracked multiple times demonstrated repeatability of daily movement distance between nights, between summer and winter, and between consecutive winters. The field cost of activity per unit distance was estimated as 15.6 kJ km(-1) from the partial regression coefficient of a multiple linear regression model, a value not significantly different from the incremental cost of locomotion derived from laboratory measurements. The field cost of activity was not affected by season, despite the expectation of higher costs of activity in the winter with increased thermoregulatory expenditure. The large daily movement distances resulted in significant activity energy expenditure (11%-33% of field metabolic rate), with a mean of 21% of field metabolic rate expended in activity during nonreproductive seasons.