Contrasting movement patterns of nectar-collecting and pollen-collecting bumble bees (Bombus terricola) on fireweed (Chamaenerion angustifolium) inflorescences

Abstract. 1. Movements of nectar and pollen-foraging bumble bees on inflorescences of Chamaenerion angustifolium (L.) J. Holub (fireweed or rosebay willow herb) were compared with predictions based on reward distributions and optimality principles. Observations suggest that nectar and pollen-gathering bumble bees behave according to the same set of reward maximization criteria when foraging from flowers of this species.
2. Both kinds of foragers matched their arrival points with the vertical positions on inflorescences in which the densities of their respective food resources were greatest. For nectar-foragers, this point was located at the lowest tier of flowers, whereas for pollen-foragers it was found in the middle of the inflorescences. Nectar and pollen-foraging bees both moved upward on inflorescences following gradients from high to low reward availability.
3. Nectar-foragers responded to decreases in inflorescence size over the season by reducing the number of flower visits made on each raceme. Number of flowers visited by pollen-foragers was low throughout and reflected the scarcity of male-phase flowers on racemes. Flower revisitation rates were low for both kinds of workers, but were slightly higher for those collecting pollen.     

Windows of opportunity and the temporal structuring of foraging activity in a desert solitary bee

1. Females of the desert solitary bee Anthophora pauperata collect nectar and pollen almost exclusively from Alkanna orientalis (Boraginaceae). The bee and plant are found together in the early spring, living in the bottom of steep-sided wadis (dry river valleys) at an altitude of 1500 m in Egyptian Sinai. 2. Female A. pauperata showed clear morning and afternoon peaks in foraging activity, separated by a 2–3 h midday period spent in their underground nests. This study analyses the following in order to identify the factors structuring this daily pattern: thermal aspects of the bee and its environment, temporal patterns of resource provision by the plant, and female nectar and pollen foraging behaviour. 3. Although A. pauperata can generate substantial heat endothermically, morning and evening ambient temperatures well below 10 °C defined a thermal window within which foraging occurred. Maximum air temperatures were moderate (25–30 °C), and examination of the physiology and behaviour of A. pauperata suggests that the midday reduction in flight activity was not due to thermal constraints. 4. Alkanna orientalis produces protandrous hermaphroditic flowers. Female A. pauperata collected pollen from male-phase flowers and harvested nectar preferentially from female-phase flowers. Although the nectar standing crop was relatively constant throughout the day, pollen availability peaked strongly in the early afternoon. 5. Female A. pauperata visited young male-phase flowers as soon as they opened, generating an early afternoon peak in pollen foraging activity and depleting the pollen standing crop rapidly. A morning peak in pollen foraging occurred when females gleaned remnant pollen from flowers that had opened the previous day. Pollen availability in the morning was far lower than in the early afternoon, and the time taken to collect a full pollen load in the morning was significantly longer. Collection of pollen in the morning despite very low resource availability suggests that pollen may be a limiting resource for A. pauperata. 6. In contrast to many existing examples of bimodal activity patterns in highly endothermic bees, the bimodal activity patterns of female A. pauperata appear to be driven not by thermal considerations but by daily patterns of pollen release from its principal food source.     

Thermal constraints on activity scheduling and habitat choice in baboons

The importance of thermoregulation as a constraint on behavior has received comparatively little attention in relation to other ecological factors. Despite this, a number of studies suggested that high temperature may represent an important ecological constraint. This paper examines the impact of temperature on activity scheduling in a troop of chacma baboons (Papio hamadryas ursinus) at De Hoop Nature Reserve, South Africa. Once the daily, seasonal, and individual effects were controlled for, the "perceived environmental temperature" (PET), which accounts for the relative contributions of solar radiation, wind speed, and humidity on shade temperature, was a significant constraint on behavior. With high PET, feeding declines, and there is an increase in grooming and particularly resting behavior. Baboons thus engage in more sedentary behaviors as temperature increases, with significantly higher levels of resting and grooming when temperature exceeds the approximate thermal neutral zone for baboons. Seeking shade is an important behavioral response to thermal stress, and PET was a significant determinant of whether an animal was in shade while engaged in either resting or grooming behavior. Furthermore, the proportion of time spent in shade increased across air temperatures that were below, within, and above the thermal neutral zone for baboons. Finally, since resting and grooming are conducted preferentially in certain habitat types, thermoregulatory considerations also impact on patterns of habitat choice and day-journey routes. This suggests that the thermal environment is an ecological variable that should be given greater consideration in future studies of primate behavior.     

Thermal constraints on foraging in adult european starlings

Summary The operative temperature of the environment was estimated for starlings using hollow, unheated taxidermic mounts. On average, adults foraging in full sun were characterized by shorter foraging bouts than those adults foraging in full shade. Simultaneous observations of air temperature, operative temperature, and the foraging duration of adults indicated that air temperature was a poor predictor of the maximum length of a foraging bout. The operative temperature of the environment was not correlated to the maximum and mean length of foraging bouts for temperatures below 31.5°C, but was negatively related to maximum and mean foraging duration for values above 31.5°C. I also found that foraging adults experiencing high thermal loads (T _e31.5°C) were less likely to return to the nest with food. These results raise the possibility that adults may be limited in their utilization of foraging sites due to an inability to cope with heat load, and that much of the loafing behavior observed for breeding birds may be behavior to avoid heat stress. The implication for seasonal variation of clutch size is discussed.     

Diurnal activity patterns in hoverflies (Diptera, Syrphidae)

Abstract. 1. Time-budgets are constructed from censuses of hoverflies. Larger species spend less time in flight.
2. Most species are active under similar conditions of light intensity, but a shade-tolerant (Melanostoma scalare Fabr.) and a sun-loving species (Metasyrphus corollae Fabr.) were identified.
3. Large species become active (i.e. move, by flying or feeding) at lower temperatures than small ones, except M.scalare, which is tolerant to cool temperatures. This means that, M.scalare apart, the order of species appearing during the day is size-dependent, largest first.
4. Previous claims about the diel periodicity of syrphids can be reconciled by considering the importance of individual thermal balance.
5. Tolerance to low temperatures in small hoverflies is associated with feeding on anemophilous pollen; this may indicate a proline-fuelled flight.     

Thermal effects on activity patterns and behavioural switching in a concourse of foragers on Stachytarpheta mutabilis (Verbenaceae) in Papua New Guinea

Summary 1. The foraging activities of the papilionid butterflies Ornithoptera priamus poseidon and Papilio ulysses, and the solitary bee Amegilla sapiens (Apoidea, Anthophoridae) on the shrub Stachytarpheta mutabilis were studied in highland Papua New Guinea. 2. The insects' activity patterns were analysed at three sites with differing diurnal microclimate variation. O. priamus and A. sapiens foraged in the morning (after a period of basking and wing-whirring) and late afternoon when temperatures were well below daily maxima, whereas P. ulysses showed foraging peaks during the hottest part of the day. 3. Site choice by all 3 species appeared to be determined primarily by temperature, but within the limits imposed by temperature, nectar supplies probably determined which site was visited. 4. P. ulysses showed interspersed foraging and courtship behaviour, and no behavioural switching was observed for this species. At high temperatures, both O. priamus and A. sapiens ceased foraging and showed territorial and courtship behaviour. This behavioural change allowed avoidance of heat stress, and occurred even when nectar supplies were maintained at high levels. 5. Thermal effects on behavioural switching in these insects are compared with related phenomena in other bees and butterflies.     

长白山北坡椴树阔叶红松林群落主要树种分布格局的研究

应用方差 /均值比检验、波松分布的X2 检验及负二项分布的X2 检验 3种方法 ,对比不同的取样样方 ,研究了椴树阔叶红松林群落主要树种的分布格局 ,并根据 1hm2 样地的定位图进行检验 .研究结果表明 ,乔木树种的合适取样样方为 5m× 5m ,其中红松、椴树、水曲柳、山槐、白牛子属于聚集型分布 ,蒙古栎、春榆属于随机分布 .     

The predatory behavior of wintering <Emphasis Type="Italic">Accipiter</Emphasis> hawks: temporal patterns in activity of predators and prey

Studies focused on how prey trade-off predation and starvation risk are prevalent in behavioral ecology. However, our current understanding of these trade-offs is limited in one key respect: we know little about the behavior of predators. In this study, we provide some of the first detailed information on temporal patterns in the daily hunting behavior of bird-eating Accipiter hawks and relate that to their prey. During the winters of 1999–2004, twenty-one sharp-shinned hawks (A. striatus) and ten Cooper’s hawks (A. cooperii) were intensively radio tracked in rural and urban habitats in western Indiana, USA. Cooper’s hawks left roost before sunrise and usually returned to roost around sunset, while sharp-shinned hawks left roost at sunrise or later and returned to roost well before sunset. An overall measure of Cooper’s-hawk-induced risk (a composite variable of attack rate and activity patterns) generally reflected the timing of prey activity, with peaks occurring around sunrise and sunset. In contrast, risk induced by the smaller sharp-shinned hawk did not strongly reflect the activity of their prey. Specifically, an early morning peak in prey activity did not correspond to a period with intense hawk activity. The lack of early morning hunting by sharp-shinned hawks may reflect the high risk of owl-induced predation experienced by these hawks. The net effect of this intraguild predation may be to “free” small birds from much hawk-induced predation risk prior to sunrise. This realization presents an alternative to energetics as an explanation for the early morning peak in small bird activity during the winter.     

Descending influences from nucleus raphe magnus on fusimotor neurone activity in rats

1. 1.Single fusimotor fibres were isolated in the ventral roots of lumbosacral segments of urethane-anaesthetized rats, and effects of electrical stimulation of the nucleus raphe magnus (NRM) on their spontaneous activity were investigated. The experiments were carried out in rats whose bilateral preoptic and anterior hypothalamic regions (PO/AH) were electrolytically destroyed to eliminate the influences of these regions to fusimotor activity.

2. 2.Of 44 fusimotor fibres studied, 38 (86%) were found to be affected by NRM stimulation. The effects of NRM stimulation were classified according to their response pattern: primary depression (D-type, n = 24), facilitation followed by depression (F-D-type, n = 5) and primary facilitation (F-type, n = 8). The most predominant effect of NRM stimulation upon fusimotor activity was characterized by a strong depression followed by a complete cessation of firing lasting either for a short period or for more than 30 min (D- and F-D-type).

3. 3.In three fusimotor fibres studied in the different preparations, it was observed that a NRM-evoked depression response was blocked by an intraperitoneal administration of a serotonin antagonist, p-chlorophenylalamine (p-CPA) (10 mg/kg).

4. 4.The results indicate that the NRM exerts descending inhibitory or facilitatory influences on fusimotor neurones, and suggest that cold shivering is controlled by modulating fusimotor neurone activity via the serotonergic raphe-signal pathways.

Influence of elevated CO2 and ultraviolet-B radiation levels on floral nectar production: a nectary-morphological perspective

 Investigations of the effects of two global events – elevated CO₂ levels and enhanced ultraviolet-B (UV-B) radiation – on floral nectar production are reviewed from twelve dicotyledonous families. Furthermore, to allow comparisons between nectary morphology and nectar production in treated plants of these fifteen species, new data on floral nectary structure are provided for Malcolmia maritima (L.) R. Br. (Brassicaceae) and Scabiosa columbaria L. (Dipsacaceae). All but the last taxon possessed mesenchymatic floral nectaries with surface stomata. Few clear relationships existed between nectary morphology and various physiological responses to CO₂ or UV-B enrichment, indicating that species responded notwithstanding nectary structure itself. Overall, nectar-solute concentration was least affected by elevated CO₂ or UV-B radiation; consequently, changes in nectar volume were responsible for differences in nectar-sugar production per flower. Three species of Fabaceae experienced no change in floral nectar production upon exposure to elevated CO₂. To date, no study of enhanced UV-B radiation reported a consistent reduction in floral nectar production; three species of Brassicaceae responded differently, but various levels of ozone depletion were simulated. Experimentation with more taxa – including those possessing nectary types such as septal (gynopleural) nectaries (e.g. many monocotyledons) or aggregations of glandular trichomes – and expanding such physiological studies to species possessing extrafloral nectaries, are recommended. Received August 8, 2002; accepted November 23, 2002 Published online: June 2, 2003     

Thermal constraints on daily patterns of aggregation and density along an intertidal gradient in the periwinkle Echinolittorina peruviana

Variations in environmental temperature have both direct and indirect effects that affect organisms at levels ranging from intra-cellular physiological processes to ecological patterns. These variations are especially important for intertidal marine ectotherms such as littorinids since they alternate between periods of immersion in seawater, and must also experience long periods of emersion. In central Chile, Echinolittorina peruviana is one of the most conspicuous species on rocky intertidal shores, occurring at high tidal levels and in the splash zone. The species is known to resist direct exposure to the sun for long periods, although juveniles tend to be restricted to protected microhabitats. Adults show seasonal variations in abundance and vertical distribution and may form aggregations that have been shown to help reduce water loss and body temperature. In this study, we evaluate the relationship between daily thermal variations throughout the vertical distribution of this species and how these affect the patterns of density and aggregation. Our results suggest that one of the leading determinants of the spatio-temporal variation of density in E. peruviana may be operative temperature (T_O: the amount of stored heat resulting from the balance between heat fluxes into and out of the body, measured with taxidermic mounts mimicking heat transfer properties of the snail). T_O showed a strong negative relationship with density and a strong positive relationship with aggregation in the highest intertidal level monitored. The strength of these relationships decreased in importance at lower levels. While T_O alone cannot explain the abundance of E. peruviana throughout its range of distribution, our results show that it does have a strong influence that should be considered in addition to other ecological factors affecting the density of intertidal littorinids.     

A comparative study of the effects of laser and light-emitting diode radiation on superoxide dismutase activity and nitric oxide production in rat wound fluid

The effect of laser and light-emitting diode radiation in the visible region of the spectrum on the content of reactive nitrogen species and superoxide dismutase activity in rat wound fluid was studied. The efficiency of action of coherent laser radiation and incoherent light-emitting diode radiation in the red region of the spectrum on the parameters analyzed was compared. The study was performed using the model of cut aseptic wounds proposed by L.I. Slutskii. A He-Ne laser (632 nm) or an U-332B light-emitting diode (630 nm) was used as the source of radiation. It was shown that (1) exposure of wounds to visible light of both laser and light-emitting diode causes dose-dependent changes in superoxide dismutase activity and nitrite production and that (2) radiation coherence does not play a significant role in the changes in superoxide dismutase activity or nitric oxide production by wound fluid phagocytes.     

清凉峰国家级自然保护区华南梅花鹿分布及活动规律

2014年12月至2016年12月,在浙江清凉峰国家级自然保护区的千顷塘区域,利用网格式红外相机法,对华南梅花鹿的分布及活动规律进行研究。结果显示,华南梅花鹿在千顷塘区域的核心区、缓冲区和实验区均有分布。其中华南梅花鹿在1200—1300 m的高海拔区域拍摄率最高(10.32%),其次是700—800 m的区域,而600—700 m的低海拔区域最低;在6种不同植被类型中,落叶阔叶林中拍摄率最高(4.60%),其次是针叶林,而常绿阔叶林最低。华南梅花鹿各月份的日活动差异指数α存在极显著差异(P0.01),冬季的α值的平均数明显高于其他3季,这表明华南梅花鹿在冬季的活动时间分配相对其他季节更不均匀,活动时间较为集中。华南梅花鹿各月份间的昼行性指数β存在极显著差异(P0.01),年度各月份β值的平均值为0.60(13/24),表明华南梅花鹿是一种昼行性动物。利用季节性活动强度指数γ发现,华南梅花鹿四季活动有两个低谷期(10:00—11:00和19:00—20:00),γ值不存在显著差异(P0.05),而日活动高峰期一般有3个(7:00—9:00,12:00—14:00,17:00—19:00)。     

The effect of hummingbird flower mites on nectar availability of two sympatric Heliconia species in a Brazilian Atlantic forest

BACKGROUND AND AIMS: Hummingbird flower mites feed and reproduce in flowers of host plants pollinated by hummingbirds, and use the nostrils and bill of the hummingbird to move from plant to plant. These mites compete with the pollinator for the nectar produced by flowers. An investigation was made of the relationship between the pattern of nectar production and the effects of hummingbird flower mites in the flowers of two sympatric species of Heliconia (Heliconiaceae). METHODS: Nectar production was sampled by carrying out two experiments: 2-hour intervals and accumulated nectar. Flowers with and without mites were used in both experiments. KEY RESULTS: Exclusion of mites increased nectar production, especially in accumulated daily production (a maximum of 49 % more nectar). Both Heliconia species had the same pattern of nectar production: a high concentration in the morning, which was progressively reduced as the day passed. This pattern of nectar production coincides with the behaviour of the pollinator, which makes more frequent visits in the morning, as observed in a previous study. CONCLUSIONS: The results suggest that the impact of mites on nectar availability of Heliconia is more important with regard to total volume of nectar produced irrespective of flower longevity. A high variation among individuals in nectar produced in the populations was also observed. Hummingbird flower mites strongly affect availability of nectar for hummingbirds.     

Online measurement of the respiratory activity in shake flasks enables the identification of cultivation phases and patterns indicating recombinant protein production in various Escherichia coli host strains

Escherichia coli is commonly used for recombinant protein production with many available host strains. Screening experiments are often performed in batch mode using shake flasks and evaluating only the final product concentration. This conventional approach carries the risk of missing the best strain due to limited monitoring capabilities. Thus, this study focuses on investigating the general suitability of online respiration measurement for selecting expression hosts for heterologous protein production. The oxygen transfer rate (OTR) for different T7‐RNA polymerase‐dependent Escherichia coli expression strains was compared under inducing and noninducing conditions. As model enzymes, a lipase A from Bacillus subtilis (BSLA) and a 3‐hydroxybutyryl‐CoA dehydrogenase from Thermus thermophilus (HBD) were chosen. Four strains were compared during expression of both enzymes in autoinduction medium. Additionally, four strains were compared during expression of the BSLA with IPTG induction. It was found that the metabolic burden during recombinant protein production induces a phase of constant OTR, while undisturbed cell growth with no or little product formation is indicated by an exponential increase. This pattern is independent of the host strain, expressed enzyme, and induction method. Furthermore, the OTR gives information about carbon source consumption, biomass formation, and the transition from production to noninduced second growth phase, thereby ensuring a fair comparison of different strains. In conclusion, online monitoring of the respiration activity is suited to qualitatively identify, if a recombinant protein is produced by a strain or not. Furthermore, laborious offline sampling is avoided. Thus, the technique is easier and faster compared to conventional approaches. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:315–327, 2018     

Zoning has little impact on the seasonal diel activity and distribution patterns of wild boar (Sus scrofa) in an UNESCO Biosphere Reserve

Understanding the spatio‐temporal distribution of ungulates is important for effective wildlife management, particularly for economically and ecologically important species such as wild boar (Sus scrofa). Wild boars are generally considered to exhibit substantial behavioral flexibility, but it is unclear how their behavior varies across different conservation management regimes and levels of human pressure. To analyze if and how wild boars adjust their space use or their temporal niche, we surveyed wild boars across the core and buffer zones (collectively referred to as the conservation zone) and the transition zone of a biosphere reserve. These zones represent low and high levels of human pressure, respectively. Specifically, we employed a network of 53 camera traps distributed in the Schaalsee UNESCO Biosphere Reserve over a 14‐month period (19,062 trap nights) and estimated circadian activity patterns, diel activity levels, and occupancy of wild boars in both zones. To account for differences in environmental conditions and day length, we estimated these parameters separately for seven 2‐month periods. Our results showed that the wild boars were primarily nocturnal, with diurnal activity occurring dominantly during the summer months. The diel activity patterns in the two zones were very similar overall, although the wild boars were slightly less active in the transition zone than in the conservation zone. Diel activity levels also varied seasonally, ranging from 7.5 to 11.0 h day⁻¹, and scaled positively with the length of the night (R ² = 0.66–0.67). Seasonal occupancy estimates were exceptionally high (point estimates ranged from 0.65 to 0.99) and similar across zones, suggesting that the wild boars used most of the biosphere reserve. Overall, this result suggests that different conservation management regimes (in this case, the zoning of a biosphere reserve) have little impact on wild boar behavior. This finding is relevant for wildlife management in protected areas where possibly high wild boar densities could interfere with conservation goals within these areas and those of agricultural land use in their vicinity.     

Effect of roughage level in a total mixed ration on feed intake, ruminal fermentation patterns and chewing activity of early-weaned calves with ad libitum access to grass hay

In this study, two total mixed rations (TMR, based on dry ingredients) consisting (per kg dry matter (DM)) of 300 or 400 g finely chopped hay mixture of grass and alfalfa (H30 versus H40) were compared concerning their effects on dry matter intake (DMI), ruminal fermentation patterns and chewing activity of early-weaned (8 weeks milk-fed) calves. Ten ruminally cannulated male German Holstein calves were randomly assigned to two dietary treatments (n = 5) and observed from an age of 8–15 weeks. One group received the H30 (11.3 MJ metabolizable energy (ME)/kg DM) and the other the H40 (10.7 MJ ME/kg DM) TMR. All calves received grass hay (9.0 MJ ME/kg DM) separately. Water, TMR and hay were offered ad libitum twice daily (08:00 and 16:00 h). Rumen fluid was collected via cannula at an age of 9, 11, 13 and 15 weeks, twice weekly just prior to as well as 1, 3, 5 and 7 h after morning feeding. Chewing activity was recorded by a special head collar. As the calves aged DMI increased rapidly congruent with the recommended range for weaned calves. Because of the differing energy supply, calves receiving the H30 TMR were heavier than calves receiving the H40 TMR (139 kg versus 123 kg, P=0.007). During the trial ruminal pH of all calves were within the target range (6.2 ± 0.5), indicating physiological ruminal fermentation patterns. Daily mean ruminal pH was uninfluenced by treatment, however at an age of 13 and 15 weeks H30 showed a higher short chain fatty acid (SCFA) level than H40 (P=0.098; P=0.036). At an age of 15 weeks H30 showed a critical decrease in ruminal pH (3 h after feeding: 5.7) corresponding to a higher ruminal SCFA concentration (148.2 mmol/L, P=0.007). Chewing activity was well developed at an early age due to an increasing DMI after weaning. At an age of 15 weeks chewing activity (per day: 613–743 min total chewing; 358–418 min rumination) was similar to that of adult cows. In summary, feeding a dry TMR consisting per kg DM of 300–400 g hay to early-weaned calves can be recommended for a successful calf rearing up to an age of 15 weeks.