Flight tunnel response of codling moth Cydia pomonella to blends of codlemone,codlemone antagonists and pear ester

Upwind orientation flights of codling moth males Cydia pomonella L. to a single source of sex pheromone (E,E)‐8,10‐dodecadienol (codlemone) are significantly reduced when blending it with pheromone antagonists, either with codlemone acetate, (E,E)‐8,10‐dodecadienyl acetate, or with the codlemone isomer (E,Z)‐8,10‐dodecadienol. However, once activated by a pheromone stimulus, males no longer distinguish between a pheromone source and these antagonistic blend sources. This shows that the pheromone stimulus required for the initiation of an upwind flight response differs from the stimulus for maintaining upwind flight and landing at the source. In contrast to pheromone antagonists, males discriminate between pheromone alone and a blend source of pheromone and the plant volatile pear ester, ethyl (2E,4Z)‐2,4‐decadienoate. This indicates a difference in the detection and neural integration of pheromone and plant volatile stimuli.     

Strong relationships between vegetation and two perpendicular climate gradients high on a tropical mountain in Hawai‘i

Aim We compared vegetation patterns at high elevation on a tropical mountain with edaphic properties and position along climate gradients to examine this landscape’s potential sensitivity to climate change. Location Our study covers the cloud forest, the ecotone at the cloud forest’s upper limit, and the alpine grassland, on the north‐east corner of windward Haleakalā, Hawai‘i. The study area brackets the mean trade wind inversion (TWI), encompasses a perpendicular, east–west precipitation gradient and includes multiple edaphic contexts. Methods We collected vegetation structure and composition data in 134 plots from 1900 to 2400 m elevation, stratified east to west. We used classification trees to compare species assemblage groups with spatial (elevation, easting, aspect) and edaphic (substrate age, texture, degree slope) variables derived from a 10‐m digital elevation model and a digital geological map. Results The forest line was physiognomically sharp, and a Shipley–Keddy test showed that species distributional limits were aggregated there. Forest line elevation was not consistent, but dropped nearly 200 m from east to west. Indicator taxa for positions above or below the forest line varied from east to west. Hierarchical clustering identified species assemblage groups with significantly different composition that were distributed across the TWI and/or along east–west climate gradients. Classification trees showed that edaphic properties were not well associated with species assemblage groups, but position along two perpendicular climate gradients was. Compositional turnover was detected along both elevational and east–west gradients. Turnover of the cloud forest’s epiphytic community was particularly pronounced across east–west gradients. Lichen abundance was significantly higher at the drier end of the east–west moisture gradient, and bryophyte abundance was higher at the wetter end. Main conclusions Modern spatial patterns suggest that this landscape will respond to changes in moisture balance through changes in species assemblage and structure, especially at the ecotone. Furthermore, ecotone response to climate change may vary from east to west because of differences in species‐specific constraints or climatic context.     

Attraction of the sandfly Lutzomyia longipalpis to possible biomarker compounds from dogs infected with Leishmania infantum

Lutzomyia longipalpis (Diptera: Psychodidae) is the primary vector of Leishmania infantum (Kinetoplastida: Trypanosomatidae) in the Americas. Studies have been carried out to identify new alternatives for monitoring and controlling this sandfly species, particularly with the use of chemical baits. The attractiveness of odours emitted by foxes and alcohols found in some plants has already been demonstrated in laboratory tests with Lu. longipalpis. However, no studies have evaluated the responses of these insects to volatile organic compounds (VOCs) emitted by dogs. The present study was carried out to investigate the effects on Lu. longipalpis of individual and blends of VOCs identified in hair from dogs infected with L. infantum. Effects in male and female Lu. longipalpis were assessed using wind tunnel methodology. Individual compounds including octanal, nonanal, decanal and heptadecane showed capacity for activating and/or attracting male Lu. longipalpis. Only decanal and nonanal showed effects on females. The combination of octanal, decanal and heptadecane increased activation and attraction behaviour in male sandflies, as did the blend of octanal and decanal. These findings indicate that VOCs emitted by dogs may be an interesting source of new attractants of sandflies.     

Weak-field ELF magnetic interactions: Implications for biological change during paleomagnetic reversals

Contrary to the belief that paleomagnetic reversals are not biologically significant, we find good reason to think otherwise. Attention is drawn to polarity transitions, time intervals a few thousand years long that follow the collapse of the existing geomagnetic dipole moment and precede the establishment of the new, oppositely directed moment. The geomagnetic field during transitions is reduced to a maximal mean intensity about 10% of the stable field and can exhibit low-frequency perturbations comparable to numerous laboratory-based extremely low frequency (ELF) studies reporting biological interactions, making it very likely that similar interactions must occur over the course of a polarity transition. This conclusion is strengthened by reports of medical problems that significantly correlate with intense solar winds, events that also generate ELF perturbations similar to those that can occur during polarity transitions.     

Climate and climatic variability at Lake Myvatn

The climate of the Lake Myvatn region is examined through the use of weather station data, using the years from 1971 to 2000 as a reference period. Variations in mean monthly temperature and precipitation at Reykjahlid (Myvatn) are compared with variations at seven other weather stations in north east Iceland. The area is drier and colder than coastal stations and exhibits a seasonal cycle in temperature that is larger than found at the coast. The temperature is significantly influenced by the number of sunlight hours only during the summer months. During summer, the influence of a sea breeze circulation can be clearly identified.The variability of climate since 1936 is also examined in comparison with the seven other weather stations. It is found that temperature variations at the different stations are highly correlated, but for precipitation the correlation is significant but much weaker.The influence of the large scale atmospheric circulation on temperature and precipitation at Lake Myvatn is also examined. It is found that the air temperature at Lake Myvatn is most sensitive to an east-west dipole in the large scale sea surface pressure field, i.e. to a pattern that is very different from the spatial pattern associated with the North Atlantic Oscillation (NAO). Precipitation at Lake Myvatn is to some degree influenced by the NAO, but generally precipitation is associated with northerly winds and cold temperatures whereas southerly winds at Lake Myvatn are likely to be drier.     

Thigmomorphogenesis: Field and laboratory studies of Abies fraseri in response to wind or mechanical perturbation

Field- and greenhouse-grown Abies fraseri (Pursh) Poir. (Fraser fir) were analyzed for wind- or mechanically-induced flexure changes. These changes included inhibition of stem and needle elongation, reinforcement of branch bases around the stem, and increased radial growth in the direction of the mechanical perturbation (MP). Mature trees exposed to high wind conditions were severely flag-formed. These modified tree crowns had a lower drag than crowns of non-flag formed trees in wind-tunnel tests. In both field-grown and greenhouse-grown A. fraseri , MP induced a decrease in flexibility and increased elasticity of the stems. The increased radial growth of the stems overrode the increase in elasticity, resulting in the overall decrease in flexibility. The increase in radial growth caused by wind or mechanical flexure was due to greater cell divisions of the vascular cambium, resulting in increased numbers of tracheids. The decrease in stem elongation in these trees was due, at least in part, to a decrease in tracheid length. The potential biological and mechanical significance of these induced growth changes in trees are addressed. The data support the thigmomorphogenetic theory, which states that plants respond to wind and other mechanical perturbations in a way that is favorable to the plant for continued survival in windy environments.     

Factors affecting searcher efficiency and scavenger removal of bat carcasses in Neotropical wind facilities

Bat fatalities at wind facilities have been reported worldwide, and environmental impact assessments depend on searches for carcasses around wind turbines to quantify impacts. Some of the carcasses may go undetected by search teams or be removed by scavengers during search intervals, so these biases must be evaluated and taken into account in fatality estimation. We investigated the influence of different factors on searcher efficiency and scavenger removal in a dry forest area in northeastern Brazil, one of the regions with the highest density of wind turbines in the Neotropics. We conducted searcher efficiency and scavenger removal trials around 34 wind turbines from January 2017 to January 2018. Searcher efficiency was influenced by cover type, season, and carcass size, ranging between 12% for small bats in shrub vegetation during the rainy season and 96% for large bats in absent or sparse vegetation during the dry season. Carcass type and season affected scavenger removal; carcass persistence time was shorter for chicks (1.2 days) than for bats and mice (2.1 days), and the probability of a carcass persisting for a whole day was higher in the rainy season, while the probability of carcass persistence for 7, 14, and 28 days was higher in the dry season. The scavenger community was composed of canids, birds of prey, and insects, with systematic removal of carcasses by the crab-eating fox (Cerdocyon thous) throughout the year and by dung beetles in the rainy season. Based on our findings, impact assessments of wind facilities on bats should conduct searcher efficiency trials in all seasons and cover types around wind turbines, using bat carcasses or models of different sizes. Scavenger removal trials should cover all seasons as well, and use mouse carcasses (but not chick carcasses) as surrogates for bats.     

Possible domestic dispersal of Bactrocera dorsalis during 2015 occurrence on the small islands of south‐western Japan

Although Japan has maintained the state of eradication of the oriental fruit fly, Bactrocera dorsalis Hendel complex (Diptera: Tephritidae) since 1986, B. dorsalis complex are occasionally trapped within a limited area and short time period on Japan's small south‐western islands. Trapping events occurred on Amamioshima Island, Kagoshima Prefecture, in 2015, and male adults were also caught in surveillance traps on neighbouring Tokunoshima (south of Amamioshima) and Yakushima (north of Amamioshima) islands as well as on several islands in Okinawa Prefecture (south of Amamioshima). To investigate possible domestic dispersal of the pest from Amamioshima Island, a trajectory analysis was performed to reveal the timing and flight distance of possible dispersal. Surveillance data indicated that the first trappings on Tokunoshima and Yakushima islands occurred in November, which was after the number of trapped male adults on Amamioshima Island peaked in late October. Backward trajectories from Tokunoshima Island beginning 14 days prior to the first trapping passed over Amamioshima Island, which suggested possible dispersal between the islands. Several backward trajectories from the islands in Okinawa Prefecture also passed Amamioshima Island. Moreover, forward trajectories from Amamioshima Island beginning during peak occurrence, from mid‐October to early November, arrived over Tokunoshima, Iheya and Okinawa islands where the flies were caught. Such circumstantial evidence suggests that domestic dispersal of B. dorsalis complex occurred on Amamioshima Island. A situation similar to that on Tokunoshima Island also occurred on Yakushima Island. However, since the number of traps has been limited until the first capture, it was not clear when and from where the immigrants arrived on the island.     

Modelling the influence of predicted future climate change on the risk of wind damage within New Zealand's planted forests

Wind is the major abiotic disturbance in New Zealand's planted forests, but little is known about how the risk of wind damage may be affected by future climate change. We linked a mechanistic wind damage model (ForestGALES) to an empirical growth model for radiata pine (Pinus radiata D. Don) and a process‐based growth model (cenw ) to predict the risk of wind damage under different future emissions scenarios and assumptions about the future wind climate. The cenw model was used to estimate site productivity for constant CO₂ concentration at 1990 values and for assumed increases in CO₂ concentration from current values to those expected during 2040 and 2090 under the B1 (low), A1B (mid‐range) and A2 (high) emission scenarios. Stand development was modelled for different levels of site productivity, contrasting silvicultural regimes and sites across New Zealand. The risk of wind damage was predicted for each regime and emission scenario combination using the ForestGALES model. The sensitivity to changes in the intensity of the future wind climate was also examined. Results showed that increased tree growth rates under the different emissions scenarios had the greatest impact on the risk of wind damage. The increase in risk was greatest for stands growing at high stand density under the A2 emissions scenario with increased CO₂ concentration. The increased productivity under this scenario resulted in increased tree height, without a corresponding increase in diameter, leading to more slender trees that were predicted to be at greater risk from wind damage. The risk of wind damage was further increased by the modest increases in the extreme wind climate that are predicted to occur. These results have implications for the development of silvicultural regimes that are resilient to climate change and also indicate that future productivity gains may be offset by greater losses from disturbances.