White-Tailed Deer Response to Vehicle Approach: Evidence of Unclear and Present Danger

The fundamental causes of animal-vehicle collisions are unclear, particularly at the level of animal detection of approaching vehicles and decision-making. Deer-vehicle collisions (DVCs) are especially costly in terms of animal mortality, property damage, and safety. Over one year, we exposed free-ranging white-tailed deer (Odocoileus virginianus) to vehicle approach under low ambient light conditions, from varying start distances, and vehicle speeds from 20 km/h to approximately 90 km/h. We modeled flight response by deer to an approaching vehicle and tested four hypotheses: 1) flight-initiation distance (FID) would correlate positively with start distance (indicating a spatial margin of safety); 2) deer would react to vehicle speed using a temporal margin of safety; 3) individuals reacting at greater FIDs would be more likely to cross the path of the vehicle; and 4) crossings would correlate positively with start distance, approach speed, and distance to concealing/refuge cover. We examined deer responses by quantiles. Median FID was 40% of start distance, irrespective of start distance or approach speed. Converting FID to time-to-collision (TTC), median TTC was 4.6 s, but uncorrelated with start distance or approach speed. The likelihood of deer crossing in front of the vehicle was not associated with greater FIDs or other explanatory variables. Because deer flight response to vehicle approach was highly variable, DVCs should be more likely with increasing vehicle speeds because of lower TTCs for a given distance. For road sections characterized by frequent DVCs, we recommend estimating TTC relative to vehicle speed and candidate line-of-sight distances adjusted downward by (1-P), where P represents our findings for the proportion of start distance by which >75% of deer had initiated flight. Where road design or conservation goals limit effectiveness of line-of-sight maintenance, we suggest incorporation of roadway obstacles that force drivers to slow vehicles, in addition to posting advisory speed limits.     

Effects of US 1 Project on Florida Key Deer Mortality

ABSTRACT Approximately 26% of annual mortality for the endangered Florida Key deer (Odocoileus virginianus clavium) occurs as deer-vehicle collisions (DVCs) on the 5.6-km section of United States Highway 1 (US 1) on Big Pine Key (BPK), but extensive urban development adjacent to sections of US 1 complicates efforts to reduce DVCs. Our objective was to evaluate the effectiveness of the US 1 Project (continuous 2.6-km system of 2.4-m fencing, 2 underpasses, and 4 experimental deer guards constructed on US 1 on BPK) in reducing DVCs along US 1. Deer used the underpasses all 3 postproject years (2003–2005); however, we observed higher underpass use in 2004 and 2005 compared to 2003. Exclusion fencing reduced deer intrusions onto the fenced section of US 1 during the 3-year period (2003, n = 7 deer; 2004, n = 4; 2005, n = 12). With a reduction of deer intrusions onto this section of US 1, DVCs decreased in the fenced area by 73–100%; however, US 1 DVCs within the unfenced sections of US 1 also increased (40%) as expected. In controlling for effects of increasing deer density and traffic volume, study results suggest that highway improvements have decreased the net risk of DVCs along US 1, which indicates that use of deer fencing, deer guards, and underpasses is applicable in other urban communities experiencing unacceptable levels of DVCs.     

County-Level Factors Contributing to Deer-Vehicle Collisions in Arkansas

ABSTRACT Arkansas harbors a substantial white-tailed deer (Odocoileus virginianus) population, boasts an expanding human population, and both enjoys and suffers the resulting consequences. A highly visible negative consequence is the occurrence of deer-vehicle collisions (DVCs). Several studies have investigated site-specific factors that may contribute to DVCs. However, few studies have explored the role of broader scale factors. In this study, we used an exploratory, multivariate approach to examine the influence of county-level factors on the density (no./1,000 km) of reported DVCs in Arkansas, USA, during 1998–2001. Factors considered to contribute to DVCs in Arkansas included human and deer population densities, urban growth, various roadway characteristics, daily traffic counts, timber harvests, and landcover composition and spatial characteristics. Using principal components and regression analysis we determined that there were 2 important components contributing to DVC densities in Arkansas. Component 1 represented a predominantly forested matrix with high edge density and contrast. Component 2 described an urban environment, with high road densities, human population densities, and average daily traffic counts. These 2 components were strongly related to DVCs (r² = 0.55, P < 0.001), with component 2 explaining the most variation (71.4%). The identification and recognition of the contribution of these broad-scale factors to DVCs provide insight useful in making informed decisions related to DVC mitigation.     

Intolerance amongst deer species at feeding: roe deer are uneasy banqueters

The function of inter-specific interactions in large herbivore assemblies is under debate. We have studied inter-specific interactions between roe and fallow deer on pastures, to assess whether competition between these Cervidae occurs through behavioural interference. Roe were displaced by fallow deer (i.e. the former moved away from the latter at a distance of >50 m) in 83% of cases (N = 127). Ninety-four percentage (N = 83) of displacement events occurred while roe deer were feeding; in 50% of these cases (N = 78), roe stopped grazing and left the feeding ground. Even when fallow deer did not show any sign of direct aggression to roe, these moved away from fallow in 72% of cases (N = 127). Vigilance rate was significantly greater in roe than in fallow deer, irrespectively of the presence of the other species. When roe and fallow deer grazed within 50 m from each other, vigilance rate increased significantly in roe, but not in fallow deer. Roe deer, in a group, were significantly more tolerant of the presence of fallow deer (even in group), than when solitary. Fallow deer seemed to be able to exclude roe deer from feeding sites through behavioural intolerance.     

Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression,Photosynthesis, and Star Visibility

Artificial light at night can be harmful to the environment, and interferes with fauna and flora, star visibility, and human health. To estimate the relative impact of a lighting device, its radiant power, angular photometry and detailed spectral power distribution have to be considered. In this paper we focus on the spectral power distribution. While specific spectral characteristics can be considered harmful during the night, they can be considered advantageous during the day. As an example, while blue-rich Metal Halide lamps can be problematic for human health, star visibility and vegetation photosynthesis during the night, they can be highly appropriate during the day for plant growth and light therapy. In this paper we propose three new indices to characterize lamp spectra. These indices have been designed to allow a quick estimation of the potential impact of a lamp spectrum on melatonin suppression, photosynthesis, and star visibility. We used these new indices to compare various lighting technologies objectively. We also considered the transformation of such indices according to the propagation of light into the atmosphere as a function of distance to the observer. Among other results, we found that low pressure sodium, phosphor-converted amber light emitting diodes (LED) and LED 2700 K lamps filtered with the new Ledtech’s Equilib filter showed a lower or equivalent potential impact on melatonin suppression and star visibility in comparison to high pressure sodium lamps. Low pressure sodium, LED 5000 K-filtered and LED 2700 K-filtered lamps had a lower impact on photosynthesis than did high pressure sodium lamps. Finally, we propose these indices as new standards for the lighting industry to be used in characterizing their lighting technologies. We hope that their use will favor the design of new environmentally and health-friendly lighting technologies.     

Deer Responses to Sounds From a Vehicle-Mounted Sound-Production System

ABSTRACT We evaluated efficacy of sound as a deterrent for reducing deer (Odocoileus spp.)–vehicle collisions by observing behavioral responses of free-ranging white-tailed deer (O. virginianus) to pure-tone sounds within their documented range of hearing. Behavior of free-ranging deer within 10 m of roadways was not altered in response to a moving automobile fitted with a sound-producing device and speakers that produced 5 sound treatments documented to be within the hearing range of white-tailed deer. Many commercially available, vehicle-mounted auditory deterrents (i.e., deer whistles) are purported to emit continuous pure-tone sounds similar to those we tested. However, our data suggest that deer whistles are likely not effective in altering deer behavior in a manner that would prevent deer-vehicle collisions.     

Hazard Assessment of Deer–Vehicle Collisions in Michigan

The relationship between deer–vehicle collision counts and vehicle miles traveled (VMT) is studied in this article using the Michigan (USA) crash database and categorized exposure data under different levels of data disaggregation. Negative binomial regression models were developed to establish the association between (human and deer) exposure and the frequency of deer–vehicle collisions. It is shown that VMT is nonlinearly correlated with the collision counts for most sets of circumstances except in rural areas. Observation of the association between the deer–vehicle collision count and the annual VMT across counties in Michigan reveals the unique characteristic of heteroskedasticity (i.e., variances of collision count are amplified with the increasing VMT). The regression results demonstrate that deer density stands out as the most significant exposure predictor in describing deer–vehicle collisions at the state level. It is recommended that differentiated exposure measurements for deer–vehicle collisions should be employed for three ecoregions in Michigan. Exposure predictors for deer–vehicle collisions appear to be more dependent on deer density in Michigan's Upper Peninsula and North Lower Peninsula ecoregions, while in the South Lower Peninsula ecoregion deer and human populations are equally important.     

Postpartum Group Cohesion of Sympatric Deer in Texas

ABSTRACT Postpartum behavior of maternal deer may be specific to species of deer and predators. We captured sympatric white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus eremicus) fawns from radiocollared adult females in 2004–2006 on rangelands of west central Texas, USA, where predators larger than bobcats (Lynx rufus) were absent. Our objective was to determine whether differences in postpartum antipredator behavior existed between deer species, and if so, examine efficacy of those strategies. We collected postpartum group cohesion data in 2004 and 2005 by using radiotelemetry and examined dead fawns for cause of mortality. During fawns' hider phase, <3 weeks postpartum, mule deer females kept fawns closer to themselves (95% CI = 39−66 m) and twins closer to each other (95% CI = 25–49 m) than did white-tailed deer females (95% CIs = 152–234 m and 163–255 m, respectively). After 30 days postpartum, familial group cohesion was similarly tight for both species. During hider phases from 2004 to 2006, predated carcasses of white-tailed deer fawns (11 of 11) were dismembered or consumed more than mule deer fawns (7 of 13, P = 0.016), which was one line of evidence for maternal defense by mule deer adults. During hider phases in 2004 and 2005, predation rate of mule deer fawns was lower than that for white-tailed deer fawns. In 2006, predation rate increased for mule deer but was similar for white-tailed deer fawns compared with previous years. The tight cohesion strategy of mule deer exhibited in 2004 and 2005 seemed successful at thwarting small predators. Without large predators, the loose cohesion strategy of white-tailed deer females was maladaptive. When meso-predators are abundant due to extermination of larger predators, predation on fawns could increase if a deer species has relatively fixed postpartum maternal antipredator behavior.     

Red deer <Emphasis Type="Italic">Cervus elaphus</Emphasis> resting place characteristics obtained from differential GPS data in a forest habitat

We recorded 30 24-h monitoring periods with 10-min sampling intervals on seven (three female; four male) Global-Positioning-System-collared adult free-ranging red deer (Cervus elaphus), from June 1999 to December 2000, in the Parc National des Cévennes, France. We observed the duration of resting bouts (n = 385) and then microhabitat variables (aspect, slope, presence of edge and litter, visibility, abundance of vegetation consumed or not) at 178 resting places. Resting bouts were shorter during the night than during the day from June to October but did not vary between sexes. Resting place visibility was lower during the day, especially in August. Daytime resting places generally offered more litter. Females used steeper slopes than males. We found higher variability in visibility and slope during the night. Aspect used did not vary from month to month or between day and night. Observed differences between day and night resting place characteristics suggest that red deer were probably facing a tradeoff between feeding and cover. Use of cover prevailed during the daytime whereas night resting place characteristics were more variable, indicating less constrained behaviour. Thus, cover (as a protection from disturbance), as well as food, is an important factor in red deer habitat use (at least during the day in disturbed areas) and should not be neglected in forest carrying capacity management.     

用距离取样技术估算森林生境中的梅花鹿密度

作者于 1999年 9、 10月在日本国日光国立公园的一个梅花鹿 (Cervusnippon)高密度区域实施了 16次夜间探照样带距离法取样调查。采用车载探照记数和激光测距仪测距 ,记录了梅花鹿的结群大小和距样带中心样线的垂直距离。应用距离取样技术 (Distancesamplingtechnique ,DST)计算的结果表明 ,梅花鹿的密度为12 5 8头 /km2 (95%CI 10 0 7-157 3 ) ,在两侧 80m宽度的调查样带内梅花鹿的总发现率为 52 5% ;对线样带法的传统动物密度计算方法 (King s ,Hayne s ,Leopold s ,Gates sⅠ ,Gates sⅡ ,Gates sⅢ和Frye s方法 )的结果验证表明 ,这些传统密度计算方法过高估算梅花鹿的密度 ,其结果为距离取样技术 (DST)计算结果的 1 76(Frye′s法 ) -6 10 (Hayne′s法 )倍。因此 ,作者建议在使用线样带法测定动物密度时应尽量避免使用这些传统计算方法 ;不同地区间及同一地区不同季节间应用线样带法调查得到的动物个体记数值之间的比较存在偏差 ,应该使用距离取样技术计算动物的密度     

Scotopic illumination enhances entrainment of circadian rhythms to lengthening light:dark cycles

Endogenously generated circadian rhythms are synchronized with the environment through phase-resetting actions of light. Starlight and dim moonlight are of insufficient intensity to reset the phase of the clock directly, but recent studies have indicated that dim nocturnal illumination may otherwise substantially alter entrainment to bright lighting regimes. In this article, the authors demonstrate that, compared to total darkness, dim illumination at night (< 0.010 lux) alters the entrainment of male Syrian hamsters to bright-light T cycles, gradually increasing in cycle length (T) from 24 h to 30 h. Only 1 of 18 hamsters exposed to complete darkness at night entrained to cycles of T > 26 h. In the presence of dim nocturnal illumination, however, a majority of hamsters entrained to Ts of 28 h or longer. The presence or absence of a running wheel had only minor effects on entrainment to lengthening light cycles. The results further establish the potent effects of scotopic illumination on circadian entrainment and suggest that naturalistic ambient lighting at night may enhance the plasticity of the circadian pacemaker.     

Cougar Prey Selection in a White-Tailed Deer and Mule Deer Community

Abstract Widespread mule deer (Odocoilus hemionous) declines coupled with white-tailed deer (O. virginianus) increases prompted us to investigate the role of cougar (Puma concolor) predation in a white-tailed deer, mule deer, and cougar community in northeast Washington, USA. We hypothesized that cougars select for and disproportionately prey on mule deer in such multiple-prey communities. We estimated relative annual and seasonal prey abundance (prey availability) and documented 60 cougar kills (prey usage) from 2002 to 2004. White-tailed deer and mule deer comprised 72% and 28% of the total large prey population and 60% and 40% of the total large prey killed, respectively. Cougars selected for mule deer on an annual basis (α_md = 0.63 vs. α_wt = 0.37; P = 0.066). We also detected strong seasonal selection for mule deer with cougars killing more mule deer in summer (α_md = 0.64) but not in winter (α_md = 0.53). Cougars showed no seasonal selection for white-tailed deer despite their higher relative abundance. The mean annual kill interval of 6.68 days between kills varied little by season (winter = 7.0 days/kill, summer = 6.6 days/kill; P = 0.78) or prey species (white-tailed deer = 7.0 days/kill, mule deer = 6.1 days/kill; P = 0.58). Kill locations for both prey species occurred at higher elevations during summer months (summer = 1,090 m, winter = 908 m; P = 0.066). We suspect that cougars are primarily subsisting on abundant white-tailed deer during winter but following these deer to higher elevations as they migrate to their summer ranges, resulting in a greater spatial overlap between cougars and mule deer and disproportionate predation on mule deer.     

Identifying threshold densities for wild deer in the UK above which negative impacts may occur

• 1 At high densities, deer populations may have adverse effects upon and within their environment. In this review we explore published and unpublished information to derive density thresholds for deer species in relation to impacts upon agriculture, forestry, conservation habitats, road traffic, and human and livestock health in the UK. Impact levels are affected by many factors other than absolute density. We therefore seek to establish the range of densities within which negative impacts might start to occur and which should trigger objective monitoring of actual impacts.
• 2 In commercial forestry, a threshold of 4 deer per 100ha has been suggested. Unfenced native woodlands seem to regenerate naturally if there are fewer than 4–5 large deer or fewer than 25 roe deer Capreolus capreolus per 100ha; open habitats may suffer only light or moderate impacts from red deer Cervus elaphus at landscape densities of 7–8 per 100ha.
• 3 Woodland bird species may have declined where deer densities are high but absolute thresholds seem impossible to establish. One study suggests maximum diversity at about 8 white‐tailed deer Odocoileus virginianus per 100ha.
• 4 Deer–vehicle collisions are affected by various factors in addition to deer density, but British and American studies suggest that accident frequencies decline at densities below 7–8 per 100ha.
• 5 Fallow deer Dama dama populations may maintain bovine TB (bTB) infection at much lower densities (25/100ha) than red or roe deer (91/100ha and 200/100ha, respectively) assuming 100% prevalence. Even at 30% prevalence a density of 75 fallow deer per 100ha could maintain bTB within the population.
• 6 We conclude that deer density alone is unlikely to be a good predictor of impact, and suggest that long‐term management should be based on assessment both of actual impacts and apparent density of deer.

     

Phylogenomics of several deer species revealed by comparative chromosome painting with Chinese muntjac paints

A set of Chinese muntjac (Muntiacus reevesi) chromosome-specific paints has been hybridized onto the metaphases of sika deer (Cervus nippon, CNI, 2n = 66), red deer (Cervus elaphus, CEL, 2n = 62) and tufted deer (Elaphodus cephalophus, ECE, 2n = 47). Thirty-three homologous autosomal segments were detected in genomes of sika deer and red deer, while 31 autosomal homologous segments were delineated in genome of tufted deer. The Chinese muntjac chromosome X probe painted to the whole X chromosome, and the chromosome Y probe gave signals on the Y chromosome as well as distal region of the X chromosome of each species. Our results confirmed that exclusive Robertsonian translocations have contributed to the karyotypic evolution of sika deer and red deer. In addition to Robertsonian translocation, tandem fusions have played a more important role in the karyotypic evolution of tufted deer. Different types of chromosomal rearrangements have led to great differences in the genome organization between cervinae and muntiacinae species. Our analysis testified that six chromosomal fissions in the proposed 2n = 58 ancestral pecoran karyotype led to the formation of 2n = 70 ancestral cervid karyotype and the deer karyotypes is more derived compare with those of bovid species. Combining previous cytogenetic and molecular systematic studies, we analyzed the genome phylogeny for 11 cervid species.     

Growth and development of Pinus radiata D. Don: the effect of light quality

Abstract. Plants of Pinus radiata of two physiological ages, juvenile (seedlings and micropropagated plantlets) and adult (rooted cuttings from mature trees), were grown under lighting fromthree combinations of metal halide (MH) and tungsten halogen (TH) lamps for up to 10 months in controlled environment rooms. The three lamp combinations, MH alone, 50: 50 MH: TH and 25:75 MH: TH by wattage, produced red: farred ratios of 4.59, 1.51, and 1.15, respectively. Photosynthetic photon flux density was 700 μmol m⁻² s⁻¹. An increase in proportion of TH lamps markedly increased shoot elongation and internode length, decreased numbers of fascicles per unit stem length and increased the proportion of stem weight in both juvenile and adult material. In addition, in adult material, it increased the number of fascicle initials and expanded fascicles per growth flush, reduced the duration of the 'rest' phase between growth flushes, accelerated the rate of elongation growth during each flush, and increased apical dominance. Tracheid length, but not diameter or wall thickness, was significantly affected by light quality and found to be associated with longer internodes. Any treatment effects on needle weight or length, stem diameter or root weight were non-significant or very small. Different clones from either the juvenile micro-propagated material or the mature rooted cuttings each showed similar patterns of response, although they often differed in the degree of response to light quality. The main response could be related solely to the red: far-red ratio and the calculated phytochrome photoequilibrium. This is the first report of phytochrome-controlled photomorphogenesis in older specimens of a woody perennial. Recommendations for artificial light sources for growing P. radiata and some ecological implications of the results are presented.     

Effect of light on the formation of atypical fruiting structures inGanoderma lucidum

Ganoderma lucidum develops atypical fruiting structures (AFSs) with non-basidiocarpous basidiospores during the incubation under light on nutrient agar media. To examine the light quality effective in inducing AFSs, 17 isolates ofG. lucidum were incubated on agar media under light from different colored fluorescent lamps. Of the 17 isolates, 13 isolates produced AFSs and basidiospores under fluorescent lamps. Nine isolates formed AFSs in a broad light region from P-B (pure blue) to P-R (pure red) lamps. The remaining 4 isolates produced AFSs under different colored fluorescent lamps. No isolates formed AFSs in the dark or under BLB (black light blue) illumination. The mycelial growth was inhibited by light illumination, especially BLB light. Although the AFSs were induced at a very low light intensity such as 0.5µmol m^–2s^–1, the optimum light intensity for the AFS formation varied depending on the kind of fluorescent lamp and the isolate. The AFS formation inG. lucidum isolates was also tested under monochromatic light produced by the combination of interference filters and colored glass filters.G. lucidum isolates were separable into various types in the responses of AFS formation to monochromatic light, indicating thatG. lucidum is heterogeneous in its photo-response with regard to AFS formation.     

Selenium concentration in liver and kidney of free living animals (roe and red deer) from West Pomerania (Poland)

The aim of this study was to determine concentrations of selenium in the liver and kidneys of roe deer and red deer from West Pomerania, depending on the season. Altogether, samples from 169 animals were collected (96 from roe deer and 73 from red deer) in 2003–2007. The mean concentration of selenium in the liver of red deer and roe deer was 0.37 μg/g and 0.62 μg/g dry weight, respectively. In kidneys, Se concentration was 2.72 μg/g d.w. in red deer and 2.99 μg/g d.w. in roe deer. In roe deer, liver selenium concentration in autumn was significantly higher than in winter (P < 0.05) and spring (P < 0.01) and significantly lower in spring than in summer (P < 0.05); likewise, kidney selenium concentration was higher in autumn than in summer. In deer, no statistically significant season-related differences were observed for liver selenium concentrations. In red deer kidneys, selenium concentration was the lowest in summer, significantly lower than in autumn and winter. Low selenium concentrations in the analyzed tissues show that the animals live in areas deficient in this element.     

Mass cultivation of Nannochloropsis sp. in annular reactors

A study was made on the mass cultivation of Nannochloropsis sp. in newly designed annular reactors operated under natural, artificial or combined illumination. The annular reactor consists of two 2-m-high Plexiglas cylinders of different diameter placed vertically one inside the other so as to form an annular culture chamber. Artificial illumination is supplied by lamps placed inside the inner cylinder. Two annular reactors of different diameter (50 and 91 cm), light path (4.5 and 3.0 cm) and illuminated surface area (5.3 and 9.3 m²) were experimented with. The effect of two different artificial light sources (fluorescent tubes and metal halide lamps) on culture productivity was investigated in both systems. The highest productivity on a per reactor basis (about 34 g (d. wt) reactor^–1 24 h^–1) was achieved with the larger reactor illuminated by a 400-W metal halide lamp. From February to May a 91-cm reactor illuminated only with natural light was operated in parallel with a 91-cm reactor subjected to combined illumination. Under natural illumination productivity increased from 16.6 g (d. wt) reactor^–1 d^–1 in February to 34.1 g (d. wt) reactor^–1 d^–1 in May. Under combined illumination productivity was 41.3 g (d. wt) reactor^–1 d^–1 in February and increased up to 48.3 g (d. wt) reactor^–1 d^–1 in May. Although the culture exposed to combined illumination always attained higher yields, the productivity gap between the two cultures decreased gradually along the season as solar radiation and minimum night temperatures increased. A 1200-L plant made of ten 50-cm annular reactors was set up and operated for two years with combined illumination yielding an average of 270 g of dry Nannochloropsis sp. biomass per day. More than 2000 L of concentrate suspension (50 g (d. wt) L^–1) of Nannochloropsis sp. were produced and successfully used by fish hatcheries as live feed for rotifers and for rearing seabream larvae with the green-water technique. This study indicates that the annular reactor can be profitably used for long-term cultivation of Nannochloropsis in temperate climates. Besides reliability and ease of operation, the main advantage of the system is that it can be used under natural illumination, yet artificial light can be also supplied to maintain high productivity levels in winter or on cloudy days.     

The effects of feedback lighting on the circadian drinking rhythm in the diurnal new world primate Saimiri sciureus

Feedback lighting provides illumination primarily during the subjective night (i.e., the photosensitive portion of the circadian cycle) in response to a given behavior. This technique has previously been used to test the nonparametric model of entrainment in nocturnal rodents. In three species (Rattus norvegicus, Mesocricetus auratus, and Mus musculus), the free-running period of the locomotor activity rhythm was similar whether the animals were exposed to continuous light or discrete light pulses occurring essentially only during the subjective night (i.e., feedback lighting). In the current experiments, feedback lighting was presented to squirrel monkeys so that light fell predominantly during the subjective night. Feedback lighting was linked to the drinking behavior in this diurnal primate so that when the animal drank, the lights went out. Despite the seemingly adverse predicament, the monkeys maintained regular circadian drinking rhythms. Furthermore, just as the period of the free-running activity rhythms of nocturnal rodents exposed to continuous light or feedback lighting were similar, the period of the drinking rhythms of the squirrel monkeys in continuous light and feedback lighting were comparable (25.6 +/- 0.1 and 25.9 +/- 0.1 hours, respectively), despite a substantial decrease in the total amount of light exposure associated with feedback lighting. The free-running period of monkeys exposed to continuous dark (24.5 +/- 0.1 hours) was significantly shorter than either of the two lighting conditions (P < 0.001). The results presented for the drinking rhythm were confirmed by examination of the temperature and activity rhythms. Therefore, discrete light pulses given predominately during the subjective night are capable of simulating the effects of continuous light on the free-running period of the circadian rhythms of a diurnal primate. The response of squirrel monkeys to feedback lighting thus lends further support for the model and suggests that the major entrainment mechanisms are similar in nocturnal rodents and diurnal primates.     

贺兰山同域分布高山麝和阿拉善马鹿秋季食性的比较研究

对贺兰山同域分布的高山麝和阿拉善马鹿秋季的粪便进行采集,利用粪便显微分析法对二者秋季食性进行了研究。分别采集高山麝和阿拉善马鹿活动区域内粪样和植物样本,分别获得两种动物40个复合粪便样本,采用频率转换法对数据处理计算,得到贺兰山同域分布的高山麝和阿拉善马鹿秋季的食性组成及组成比例。结果显示,高山麝秋季共取食植物20科30种(属),其中蓝锭果忍冬(11.96%)、秦氏黄芪(10.17%)、密齿柳(8.32%)、折枝绣线菊(6.82%)、内蒙野丁香(6.18%)组成了高山麝的主要食物;阿拉善马鹿秋季共取食植物12科29种(属),其中针茅(22.15%)、灰榆(21.14%)、早熟禾(16.90%)、小叶金露梅(11.62%)、山杨(10.00%)为阿拉善马鹿秋季的主要食物。高山麝和阿拉善马鹿共有9种食物重叠,生态位重叠指数为83.75%。秋季高山麝取食的Shannon-Wiener指数、Pieou均匀性指数、食物生态位宽度指数和最大的物种多样性指数均高于阿拉善马鹿。