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71.
A simple,band‐mounted device to measure behaviorally modified thermal microclimates experienced by birds
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Birds encounter climate at the scale of microclimates that can vary rapidly in time and space and so understanding potential vulnerability and adaptations to those microclimates requires fine‐scale measurements that accurately track thermal exposures. However, few options exist for recording the microclimates actually experienced by birds (realized microclimates). We constructed and tested a simple, low‐cost, temperature logger for recording the realized microclimates of ground‐nesting birds. We developed attachment protocols for band‐mounting Thermochron iButtons on Ring‐billed Gull (Larus delawarensis) chicks. We tested these mounted, temperature‐logging devices on 20 chicks weighing > 200 g (device weight was 4 g), attaching devices for 48 h and observing behavior before and after attachment and removal. Devices recorded temperature immediately surrounding the leg at 2‐min intervals. Recorded temperatures were strong predictors of observed thermoregulatory behaviors (panting and sitting), outperforming predictions based on air temperatures measured by basic, static approaches. Through comparison with matched controls (chicks with just a band), we detected no adverse physiological effects of devices, no effects on social or feeding behavior, and only a short‐term decrease in inactivity immediately after device attachment (likely due to increased preening). By attaching iButtons to the legs of birds, we quantified realized thermal exposure, integrating air temperature, modes of environmental heat transfer, and bird behavior at microclimatic scales. Although not yet validated for broader use, our approach (including possible miniaturization) should be suitable to measure thermal exposure of adults, not just chicks, allowing collection of data concerning thermal exposures during flight under field conditions. At ~ $25 USD per device, our approach facilitates experimental protocols with robust sample sizes, even for relatively modest budgets. 相似文献
72.
We describe the development of DNA markers for the fungal pathogen of Eucalyptus, Cryphonectria cubensis. These markers originated from cloned intershort sequence repeat polymerase chain reactions, which enrich for medium to highly repetitive DNA sequences. In total, 10 markers were isolated, eight of which were polymorphic, and these can subsequently be applied to study populations of C. cubensis. 相似文献
73.
Adoption of reduced‐impact logging (RIL) methods could reduce CO2 emissions by 30–50% across at least 20% of remaining tropical forests. We developed two cost effective and robust indices for comparing the climate benefits (reduced CO2 emissions) due to RIL. The indices correct for variability in the volume of commercial timber among concessions. We determined that a correction for variability in terrain slope was not needed. We found that concessions certified by the Forest Stewardship Council (FSC, N = 3), when compared with noncertified concessions (N = 6), did not have lower overall CO2 emissions from logging activity (felling, skidding, and hauling). On the other hand, FSC certified concessions did have lower emissions from one type of logging impact (skidding), and we found evidence of a range of improved practices using other field metrics. One explanation of these results may be that FSC criteria and indicators, and associated RIL practices, were not designed to achieve overall emissions reductions. Also, commonly used field metrics are not reliable proxies for overall logging emissions performance. Furthermore, the simple distinction between certified and noncertified concessions does not fully represent the complex history of investments in improved logging practices. To clarify the relationship between RIL and emissions reductions, we propose the more explicit term ‘RIL‐C’ to refer to the subset of RIL practices that can be defined by quantified thresholds and that result in measurable emissions reductions. If tropical forest certification is to be linked with CO2 emissions reductions, certification standards need to explicitly require RIL‐C practices. 相似文献
74.
Male moths locate conspecific females by pheromone‐induced upwind flight maintained by detecting a visual flow, termed optomotor anemotaxis. Their behavioural pattern is characterized by an upwind surge in response to a pheromone stimulus and crosswind casting after odour loss, which is considered to be reset and restarted on receipt of another pheromone pulse. However, pheromone‐stimulated males of the potato tuberworm moth Phthorimaea operculella exhibit a series of short and straight intermittent flights, or hops, when moving upwind. It is unclear whether they navigate by employing the same behavioural pattern and wind detection mechanism as that used by flying moths. To analyze odour‐modulated anemotaxis in male potato tuberworm moths, a flat wind tunnel is constructed to give regular odour stimuli to an insect regardless of its location. Moths are subjected to pheromone pulses of different frequencies to test whether they show a behavioural pattern that is reset and restarted by a pheromone pulse. Moths on the ground are also subjected to crosswind shear to examine their detection of wind direction. Path analyses reveal that males surge upwind when they receive a pheromone pulse and exhibit casting by successive hops when they lose odour. This behavioural pattern appears to be similar to that of flying moths. When the direction of the airflow is switched orthogonally, males adjust their course angle accordingly when they are on the ground. It is suggested that, instead of optomotor anemotaxis, this ‘aim‐then‐shoot’ system aids the detection of wind direction, possibly by mechanosensory means. 相似文献
75.
Host discrimination modulates brood guarding behaviour and the adaptive superparasitism in the parasitoid wasp Trissolcus semistriatus (Hymenoptera: Scelionidae)
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Because hosts utilized by parasitoids are vulnerable to further oviposition by conspecifics, host guarding benefits female wasps. The present study aims to test whether female adults regulate brood guarding behaviour by host discrimination in a solitary parasitoid Trissolcus semistriatus by presenting an intact or parasitized host egg mass to a female adult. Virgin females without oviposition experience have host discrimination ability, which enables them to adjust the number of eggs laid in the hosts. Mating experience increases superparasitism by female adults, whereas mated females achieve a higher discrimination ability as a result of oviposition experience and show a lower superparasitism rate. As expected, females exhibit brood guard after parasitizing an intact host egg mass, whereas those females visiting a previously parasitized host egg mass, do not. Because the survival of eggs in superparasitized hosts is relatively low, regulating brood guarding behaviour by host discrimination is adaptive for female wasps. 相似文献
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77.
This study aimed to prepare a novel quartz crystal microbalance (QCM) sensor for the detection of pirimicarb. Pirimicarb‐imprinted poly (ethylene glycol dimethacrylate‐N‐metacryloyl‐(l )‐tryptophan methyl ester) [p (EGDMA‐MATrp)] nanofilm (MIP) on the gold surface of a QCM chip was synthesized using the molecular imprinting technique. A nonimprinted p (EGDMA‐MATrp) nanofilm (NIP) was also synthesized using the same experimental technique. The MIP and NIP nanofilms were characterized via Fourier transform infrared spectroscopy attenuated total reflectance spectroscopy, contact angle, atomic force microscopy, and an ellipsometer. A competitive adsorption experiment on the sensor was performed to display the selectivity of the nanofilm. An analysis of the QCM sensor showed that the MIP nanofilm exhibited high sensitivity and selectivity for pirimicarb determination. A liquid chromatography‐tandem mass spectrometry method was prepared and validated to determine the accuracy and precision of the QCM sensor. The accuracy and precision of both methods were determined by a comparison of six replicates at three different concentrations to tomato samples extracted by using a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method. The limit of detection of the QCM sensor was found to be 0.028 nM. In conclusion, the QCM sensor showed good accuracy, with recovery percentages between 91 and 94%. Also, the pirimicarb‐imprinted QCM sensor exhibited a fast response time, reusability, high selectivity and sensitivity, and a low limit of detection. Therefore, it offers a serious alternative to the traditional analytical methods for pesticide detection in both natural sources and aqueous solutions. 相似文献
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80.
《Biological reviews of the Cambridge Philosophical Society》2018,93(2):897-913
Seed dispersal by animals is a complex phenomenon, characterized by multiple mechanisms and variable outcomes. Most researchers approach this complexity by analysing context‐dependency in seed dispersal and investigating extrinsic factors that might influence interactions between plants and seed dispersers. Intrinsic traits of seed dispersers provide an alternative way of making sense of the enormous variation in seed fates. I review causes of intraspecific variability in frugivorous and granivorous animals, discuss their effects on seed dispersal, and outline likely consequences for plant populations and communities. Sources of individual variation in seed‐dispersing animals include sexual dimorphism, changes associated with growth and ageing, individual specialization, and animal personalities. Sexual dimorphism of seed‐dispersing animals influences seed fate through diverse mechanisms that range from effects caused by sex‐specific differences in body size, to influences of male versus female cognitive functions. These differences affect the type of seed treatment (e.g. dispersal versus predation), the number of dispersed seeds, distance of seed dispersal, and likelihood that seeds are left in favourable sites for seeds or seedlings. The best‐documented consequences of individual differences associated with growth and ageing involve quantity of dispersed seeds and the quality of seed treatment in the mouth and gut. Individual specialization on different resources affects the number of dispersed plant species, and therefore the connectivity and architecture of seed‐dispersal networks. Animal personalities might play an important role in shaping interactions between plants and dispersers of their seeds, yet their potential in this regard remains overlooked. In general, intraspecific variation in seed‐dispersing animals often influences plants through effects of these individual differences on the movement ecology of the dispersers. Two conditions are necessary for individual variation to exert a strong influence on seed dispersal. First, the individual differences in traits should translate into differences in crucial characteristics of seed dispersal. Second, individual variation is more likely to be important when the proportions of particular types of individuals fluctuate strongly in a population or vary across space; when proportions are static, it is less likely that intraspecific differences will be responsible for changes in the dynamics and outcomes of plant–animal interactions. In conclusion, focusing on variation among foraging animals rather than on species averages might bring new, mechanistic insights to the phenomenon of seed dispersal. While this shift in perspective is unlikely to replace the traditional approach (based on the assumption that all important variation occurs among species), it provides a complementary alternative to decipher the enormous variation observed in animal‐mediated seed dispersal. 相似文献