Synergism and redundancy in a plant volatile blend attracting grapevine moth females

A flight tunnel study was done to decipher the behavioral effect of grape odor in grapevine moth Lobesia botrana. A blend of 10 volatile compounds, which all elicit a strong antennal response, attracts mated grapevine moth females from a distance, by upwind orientation flight. These 10 grape volatiles are in part behaviorally redundant, since attraction to a 3-component blend of beta-caryophyllene, (E)-beta-farnesene and (E)-4,8-dimethyl-1,3,7-nonatriene was not significantly different from the 10-component blend. Blending these three compounds had a strong synergistic effect on female attraction, and omission of any one compound from this 3-component blend almost abolished attraction. It was nonetheless possible to substitute the three compounds with the other grape volatiles which are perceived by the female antenna, to partly restore attraction. Several blends, of varying composition, elicited significant attraction. The observed behavioral plasticity in response to grape volatile blends probably reflects the variation of the natural plant signal, since females oviposit on different grape varieties, in different phenological stages.     

Altered olfactory receptor neuron responsiveness in rare Ostrinia nubilalis males attracted to the O. furnacalis pheromone blend

Three percent of E-strain Ostrinia nubilalis males fly upwind in response to the Ostrinia furnacalis pheromone blend [a 40:60 ratio of (E)-12-tetradecenyl acetate to (Z)-12-tetradecenyl acetate (E12-14:OAc to Z12-14:OAc)], in addition to their own pheromone blend [a 99:1 ratio of (E)-11-tetradecenyl acetate to (Z)-11-tetradecenyl acetate) (E11-14:OAc to Z11-14:OAc)]. We assessed the olfactory receptor neuron (ORN) responses of these behaviorally "rare" males versus those of normal males. For the three ORNs housed within each sensillum, we tested responsiveness to Z12-14:OAc, E12-14:OAc, Z11-14:OAc, E11-14:OAc, and the behavioral antagonist (Z)-9-tetradecenyl acetate (Z9-14:OAc). Z11-14:OAc, E11-14:OAc, and Z9-14:OAc stimulated ORNs exhibiting distinct small, large, and medium spike sizes, respectively. For rare and normal males, both Z12-14:OAc and E12-14:OAc usually elicited responses from the largest-spiking ORN. In many ORNs of normal males, Z12-14:OAc or E12-14:OAc stimulated the smaller-spiking ORN that is responsive to Z11-14:OAc. In rare males, detectable ORN responses from the smaller-spiking ORN in response to Z12- and E12-14:OAc were virtually non-existent. These differences in ORN tuning in rare males will tend to create an ORN firing ratio between the large- and small-spiking ORNs in response to the O. furnacalis blend that is similar to that elicited by the O. nubilalis blend.     

Burrowing Owl Mortality in the Altamont Pass Wind Resource Area

Abstract: We estimated wind turbines in the Altamont Pass Wind Resource Area (APWRA), California, USA, kill >100 burrowing owls (Athene cunicularia hypugaea) annually, or about the same number likely nesting in the APWRA. Turbine-caused mortality was up to 12 times greater in areas of rodent control, where flights close to the rotor plane were disproportionately more common and fatalities twice as frequent as expected. Mortality was highest during January through March. Burrowing owls flew within 50 m of turbines about 10 times longer than expected, and they flew close to wind turbines disproportionately longer within the sparsest turbine fields, by turbines on tubular towers, at the edges of gaps in the turbine row, in canyons, and at lower elevations. They perched, flew close to operating turbine blades, and collided disproportionately more often at turbines with the most cattle dung within 20 m, with the highest densities of ground squirrel (Spermophilus beecheyi) burrow systems within 15 m, and with burrowing owl burrows located within 90 m of turbines. A model of relative collision threat predicted 29% of the 4,074 turbines in our sample to be more dangerous, and these killed 71% of the burrowing owls in our sample. This model can help select the most dangerous turbines for shutdown or relocation. All turbines in the APWRA could be shut down and blades locked during winter, when 35% of the burrowing owls were killed but only 14% of the annual electricity was generated. Terminating rodent control and installing flight diverters at the ends of turbine rows might also reduce burrowing owl mortality, as might replacing turbines with new-generation turbines mounted on taller towers.     

Estimating Wind Turbine-Caused Bird Mortality

ABSTRACT Mortality estimates are needed of birds and bats killed by wind turbines because wind power generation is rapidly expanding worldwide. A mortality estimate is based on the number of fatalities assumed caused by wind turbines and found during periodic searches, plus the estimated number not found. The 2 most commonly used estimators adjust mortality estimates by rates of searcher detection and scavenger removal of carcasses. However, searcher detection trials can be biased by the species used in the trial, the number volitionally placed for a given fatality search, and the disposition of the carcass on the ground. Scavenger removal trials can be biased by the metric representing removal rate, the number of carcasses placed at once, the duration of the trial, species used, whether carcasses were frozen, whether carcasses included injuries consistent with wind turbine collisions, season, distance from the wind turbines, and general location. I summarized searcher detection rates among reported trials, and I developed models to predict the proportion of carcasses remaining since the last fatality search. The summaries I present can be used to adjust previous and future estimates of mortality to improve comparability. I also identify research directions to better understand these and other adjustments needed to compare mortality estimates among wind farms.     

Sensory and behavioural responses of the stable fly Stomoxys calcitrans to rumen volatiles

Analysis of volatiles from rumen digesta by gas chromatography linked antennogram recordings from Stomoxys calcitrans (L) (Diptera: Muscidae) antennal receptor cells revealed about 30 electrophysiologically active constituents, the most important of which is dimethyl trisulphide with a sensory threshold in the femtogram range. The behavioural responses of S. calcitrans to five chemostimulants (dimethyl trisulphide, butanoic acid, p-cresol, oct-1-en-3-ol and skatole) were tested in a wind tunnel where activation and attraction of hungry flies to rumen volatiles were recorded. Dimethyl trisulphide, butanoic acid and p-cresol were found to attract S. calcitrans. This sensitivity to rumen volatile constituents, that also occur in animal wastes used for oviposition by Stomoxys spp., as well as in flowers used by stable flies as sources of nectar is discussed in the context of the behavioural ecology of these flies.     

Curtailment and acoustic deterrents reduce bat mortality at wind farms

The impacts of wind energy on bat populations is a growing concern because wind turbine blades can strike and kill bats, and wind turbine development is increasing. We tested the effectiveness of 2 management actions at 2 wind-energy facilities for reducing bat fatalities: curtailing turbine operation when wind speeds were <5.0 m/second and combining curtailment with an acoustic bat deterrent developed by NRG Systems. We measured the effectiveness of the management actions using differences in counts of bat carcasses quantified by daily and twice-per-week standardized carcass searches of cleared plots below turbines, and field trials that estimated searcher efficiency and carcass persistence. We studied turbines located at 2 adjacent wind-energy facilities in northeast Illinois, USA, during fall migration (1 Aug–15 Oct) in 2018. We estimated the effectiveness of each management action using a generalized linear mixed-effects model with several covariates. Curtailment alone reduced overall bat mortality by 42.5% but did not reduce silver-haired bat (Lasionycteris noctivagans) mortality. Overall bat fatality rates were 66.9% lower at curtailed turbines with acoustic deterrents compared to turbines that operated at manufacturer cut-in speed. Curtailment and the deterrent reduced bat mortality to varying degrees between species, ranging from 58.1% for eastern red bats (Lasiurus borealis) to 94.4 for big brown bats (Eptesicus fuscus). Hoary (Lasiurus cinereus) and silver-haired bat mortality was reduced by 71.4% and 71.6%, respectively. Our study lacked a deterrent-only treatment group because of the expense of acoustic deterrents. We estimated the additional reduction in mortality with concurrent deployment of the acoustic deterrent and curtailment under the assumption that curtailment and the acoustic deterrent would have reduced mortality by the same percentage at adjacent wind-energy facilities. Acoustic deterrents resulted in 31.6%, 17.4%, and 66.7% additional reductions of bat mortality compared to curtailment alone for eastern red bat, hoary bat, and silver-haired bat, respectively. The effectiveness of acoustic deterrents for reducing bat mortality at turbines with rotor-swept area diameters >110 m is unknown because high frequency sound attenuates quickly, which reduces coverage of rotor-swept areas. Management actions should consider species differences in the ability of curtailment and deterrents to reduce bat mortality and increase energy production.     

库布齐沙漠南缘风沙-植被相互作用及其景观效应

干旱区尤其沙漠边缘地区的风沙与植被相互作用对塑造地表景观具有重要意义。选择库布齐沙漠南缘的油蒿灌丛地为研究区,开展了植被调查、风沙流观测和表层沉积物粒度采样测试,分析了顺风向植被盖度、风沙流结构与沉积物特征的沿程变化,探讨了风沙-植被相互作用及其对地表景观格局的影响。结果表明,风沙流与植被相互作用方式的改变使植物生长状况与地表蚀积模式发生变化,进而导致顺风向景观表现出明显的空间异质性。自上风向裸地过渡到均匀分布的新生油蒿和油蒿灌丛再至斑块状分布的灌丛沙堆,植被盖度与覆沙厚度先增大后减小,空气动力学粗糙度沿程不断增加且在过渡时其增幅最大,输沙率与沉积物粒度呈先减小后增大趋势,并在植被盖度与覆沙厚度最大处出现最小值。在沙漠边缘剥蚀高原上,起初适量风沙堆积促进油蒿定植与生长,均匀分布的油蒿灌丛进一步促进沙物质堆积,但当堆积厚度超过油蒿耐沙埋深度时发生退化,灌丛出现斑块状分布且风沙流在丘间地处侵蚀。据此,可理解为剥蚀高原风沙区景观异质性是风沙与植被相互协同与抑制作用的结果。     

Not putting all their eggs in one basket: bet‐hedging despite extraordinary annual reproductive output of desert tortoises

Bet‐hedging theory makes the counter‐intuitive prediction that, if juvenile survival is low and unpredictable, organisms should consistently reduce short‐term reproductive output to minimize the risk of reproductive failure in the long‐term. We investigated the long‐term reproductive output of an Agassiz's desert tortoise (Gopherus agassizii) population and conformance to a bet‐hedging strategy of reproduction in an unpredictable but comparatively productive environment. Most females reproduced every year, even during periods of low precipitation and poor germination of food plants, and the mean percentage of reproducing females did not differ significantly on an annual basis. Although mean annual egg production (clutch size × clutch frequency) differed significantly among years, mean clutch size and mean clutch frequency remained relatively constant. During an El Niño year, mean annual egg production and mean annual clutch frequency were the highest ever reported for this species. Annual egg production was positively influenced by maternal body size but clutch size and clutch frequency were not. Our long‐term results confirm earlier conclusions based on short‐term research that desert tortoises have a bet‐hedging strategy of producing small clutches almost every year. The risk of long‐term reproductive failure is minimized in unpredictable environments, both through time by annually producing multiple small clutches over a long reproductive lifespan, even in years of low resource availability, and through space by depositing multiple annual clutches in different locations. The extraordinary annual reproductive output of this population appears to be the result of a typically high but unpredictable biomass of annual food plants at the site relative to tortoise habitat in dryer regions. Under the comparatively productive but unpredictable conditions, tortoises conform to predictions of a bet‐hedging strategy of reproduction with relatively small but consistent clutch sizes. Published 2015. This article is a U.S. Government work and is in the public domain in the USA, Biological Journal of the Linnean Society, 2015, 115 , 399–410.     

浙江天童太白山不同群落植物构型比较

植物构型是植株构件在空间上的分配方式,反映了植物对环境的响应策略。通过对浙江天童太白山海拔差异很小的栲树(Castanopsis fargesii)、小叶青冈(Cyclobalanopsis gracilis)和云山青冈(Cyclobalanopsis sessilifolia)群落类型中所有植株的树高、树冠厚度、树冠面积、叶片聚集度、枝下高和距地45 cm基径等植物构型性状,以及树冠曝光指数、土壤含水率、空气温湿度、土壤p H值和风速6个环境因子的测定,分别分析乔灌木层植物构型性状及性状关系在3个群落间的变化规律。结果表明:(1)从栲树到小叶青冈至云山青冈群落,灌木层的树高、树冠厚度、枝下高和距地45 cm基径增加,叶片聚集度减小;乔木层的树高、树冠厚度、树冠面积、枝下高和距地45 cm基径均减小,叶片聚集度增大;(2)3个群落灌木层构型性状间显著相关(P0.001),而乔木层只在中低海拔群落存在相关性;(3)从栲树到小叶青冈至云山青冈群落,乔灌木层的冠层曝光指数显著增加(P0.05);(4)多元逐步回归表明,树冠曝光指数对灌木层构型性状变异的贡献最大,而风速、土壤含水率和p H值对乔木构型性状的变异起主导作用。综上得知,天童太白山乔灌木植物在不同群落间存在构型分异,植物对光资源的竞争是引起灌木构型在不同群落间变化的主要驱动因子,而对乔木植物,其构型变化更多受到风速和土壤含水量的影响。     

Response of wheat restricted‐tillering and vigorous growth traits to variables of climate change

The response of wheat to the variables of climate change includes elevated CO₂, high temperature, and drought which vary according to the levels of each variable and genotype. Independently, elevated CO₂, high temperature, and terminal drought affect wheat biomass and grain yield, but the interactive effects of these three variables are not well known. The aim of this study was to determine the effects of elevated CO₂ when combined with high temperature and terminal drought on the high‐yielding traits of restricted‐tillering and vigorous growth. It was hypothesized that elevated CO₂ alone, rather than combined with high temperature, ameliorates the effects of terminal drought on wheat biomass and grain yield. It was also hypothesized that wheat genotypes with more sink capacity (e.g. high‐tillering capacity and leaf area) have more grain yield under combined elevated CO₂, high temperature, and terminal drought. Two pairs of sister lines with contrasting tillering and vigorous growth were grown in poly‐tunnels in a four‐factor completely randomized split‐plot design with elevated CO₂ (700 µL L^?1), high day time temperature (3 °C above ambient), and drought (induced from anthesis) in all combinations to test whether elevated CO₂ ameliorates the effects of high temperature and terminal drought on biomass accumulation and grain yield. For biomass and grain yield, only main effects for climate change variables were significant. Elevated CO₂ significantly increased grain yield by 24–35% in all four lines and terminal drought significantly reduced grain yield by 16–17% in all four lines, while high temperature (3 °C above the ambient) had no significant effect. A trade‐off between yield components limited grain yield in lines with greater sink capacity (free‐tillering lines). This response suggests that any positive response to predicted changes in climate will not overcome the limitations imposed by the trade‐off in yield components.