Predators as potential dispersal agents of the nuclear polyhedrosis virus ofAnticarsia gemmatalis [Lep.: Noctuidae] in soybean

The relationships were surveyed among an introduced nuclear polyhedrosis virus (AgNPV), populations of its larval hostAnticarsia gemmatalis, and other invertebrates associated with soybean. Early applications of AgNPV to small plots effectively suppressedA. gemmatalis populations without causing detectable perturbations in populations of other phytophagous insects or invertebrate predators. Bioassays of predators collected within and outside treated areas demonstrated that many invertebrates readily fed upon AgNPV-infectedA. gemmatalis under field conditions. These results suggest that the predator complex enhances the epidemic potential of this baculovirus. The predators, by feeding upon virus infected larvae, are believed to play an important role in maintaining and disseminating virus inoculum in soybean. Florida Agricultural Experiment Station Journal Series No. 6272.     

Learning of a Mimic Odor within Beehives Improves Pollination Service Efficiency in a Commercial Crop

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Interactions between fish and salamander larvae

Summary Two species of salamander larvae (Ambystoma talpoideum and A. maculatum) were reared separately in the presence and absence of a fish (Lepomis macrochirus) in artificial ponds to measure the effects of a predator on the growth, survival, diet, and activity of larvae. The presence of L. macrochirus reduced body sizes of larvae by 18% in A. talpoideum and by 16% in A. maculatum. L. macrochirus apparently preyed on the smallest individuals. Survival in the presence of L. macrochirus decreased by 61% in A. talpoideum and by 97% in A. maculatum compared with larvae reared alone. Species identity did not significantly effect body size or survival, but an interaction effect suggested that A. maculatum was more severely affected by predators than was A. talpodeum. Activity of larvae in the water column was dramatically reduced in the presence of L. macrochirus, when larvae were restricted to the leaf litter of the benthic zone. There was overlap in the diets of fish and salamander larvae. Larvae reared in the presence of fish, however, consumed different taxa of prey as well as reduced number of prey compared to larvae reared alone. A. talpoideum larvae were more nocturnal than diurnal in the absence of fish, whereas A. maculatum larvae were equally active day and night. This experiment suggests that predator-prey relationships can change with shifts in species attributes and potentially confound apparent costs of predator avoidance with competition. Measuring the long-term dynamics of the cost-benefit relationship will help elucidate how prey balance the demands of their life history with the demands of predators.     

基于GC-IMS技术的不同红火蚁监测诱饵的风味成分分析

探讨不同红火蚁Solenopsis invicta Buren监测诱饵的风味成分,以期获得优化诱饵配方的科学依据。本文采用顶空气相色谱-离子迁移谱法分析不同红火蚁监测诱饵在60℃下的气味指纹图谱,并通过主成分分析法分析其风味物质的差异。结果共鉴定出93个信号峰和87种挥发性化合物,载体物质（CK）中具有较高强度峰的化合物包括3种苯、2种醇、3种酮、2种酯、4种醛、1种呋喃和1种烯;自主配制的诱饵（JR、ZR、JZ）的风味组成相似,较高强度峰的化合物包括2种醇、1种酸、12种醛和1-8桉叶素等;市售火腿肠（HT）中的3种烯、10种酮、1种苯、5种醛、1种呋喃、3种醚、7种醇和4种酯是具有较高强度峰的化合物。主成分分析表明,CK、HT与自主研发的诱饵聚集距离较远,三者均单独聚为一类,相互风味成分区别较大。综上所述,JR、ZR和JZ诱饵中醛类物质较多,而HT中酮类与醇类物质较为丰富。上述诱饵的风味成分分析结果能为研发精准高效的红火蚁监测专用诱饵提供重要信息。     

Butane‐2,3‐dione: the Key Contributor to Axillary and Foot Odor Associated with an Acidic Note

Human body odor, which contains several volatile organic compounds, possesses various odor qualities. To identify key volatile compounds responsible for the common unpleasant odors derived from human axillae and feet, the odor quality and intensity of 118 human axillae and feet were directly evaluated by sniffing, and odor compounds obtained from the subjects were identified. Furthermore, the sensory differences in odor intensity and quality with and without addition of butane‐2,3‐dione were evaluated by using the visual analog scale (VAS). An acidic odor was a common unpleasant note in human axillae and feet. Butane‐2,3‐dione was identified as a key compound associated with this odor. Strong positive correlations between the amount of butane‐2,3‐dione, and the odor intensities of axillae and feet were observed, and the addition of butane‐2,3‐dione solution to blended short‐chain fatty‐acid solutions caused significantly increased VAS values of axillary‐like odor, unpleasantness, and odor intensity compared to those of each solution without added butane‐2,3‐dione.     

Feeding and Refuge Use by Small Fish in the Presence of Cyanobacteria Blooms

We studied the effect of cyanobacteria on foraging and refuge use in small fish. We measured pike larval feeding in the presence of cyanobacteria by counting leftover prey. Our results showed that feeding by pike larvae on zooplankton prey decreased significantly in the presence of non-toxic cyanobacteria. The behaviour can be due to lowered vision caused by turbidity or clogging of the gills. Further, we tested whether the three-spined stickleback use toxic cyanobacteria as a refuge against predators in a choice experiment. The choice experiment was performed in a Y-maze fluviarum, where the fish could select between two different environments. Our results support the refuge use hypothesis because the three-spined stickleback clearly preferred toxic cyanobacteria to the chemical predator signal. To conclude, cyanobacteria decrease feeding rates in fish larvae, but may function as important refuge for e.g. sticklebacks, during predation pressure in pelagic algal blooms.     

Evaluation of the validity of a maximum likelihood adaptive staircase procedure for measurement of olfactory detection threshold in mice

Threshold is defined as the stimulus intensity necessary for a subject to reach a specified percent correct on a detection test. MLPEST (maximum likelihood parameter estimation by sequential testing) is a method that is able to determine threshold accurately and more rapidly than many other methods. Originally developed for human auditory and visual tasks, it has been adapted for human olfactory and gustatory tests. In order to utilize this technique for olfactory testing in mice, we have adapted MLPEST methodology for use with computerized olfactometry as a tool to estimate odor detection thresholds. Here we present Monte Carlo simulations and operant conditioning data that demonstrate the potential utility of this technique in mice, we explore the ramifications of altering MLPEST test parameters on performance, and we discuss the advantages and disadvantages of using MLPEST compared to other methods for the estimation of thresholds in rodents. Using MLPEST, we find that olfactory detection thresholds in mice deficient for the cyclic nucleotide-gated channel subunit A2 are similar to those of wild-type animals for odorants the knockout animals are able to detect.     

Perinatal olfactory learning in the domestic dog

The ability of individuals to learn about chemosensory stimuli in the prenatal, or immediate postnatal, period may be advantageous in acquiring information about "safe" foods after weaning. In this study, we examined the influence of perinatal exposure to aniseed via the mother's diet on a two-choice food test in the domestic dog. Pups were tested at 10 weeks of age following "prenatal" exposure to aniseed (the last 20 days of gestation), "postnatal" exposure to aniseed (the first 20 days after birth), "perinatal" exposure to aniseed (pre- and postnatal exposure combined), or no exposure to aniseed prenatally or postnatally (control). Perinatal exposure resulted in a significantly greater preference for the aniseed food than the other types of exposure. At 10 weeks, there was no evidence for the retention of any prenatal learning of the aniseed. It is suggested that exposure to a chemosensory stimulus across the perinatal period results in a greater effect than simply the sum of pre- and postnatal exposure due to priming of the chemosensory system via prenatal chemosensory experience. Such a system may confer survival advantages by promoting the acquisition of information about safe foods.     

Temporal integrity of an airborne odor stimulus is greatly affected by physical aspects of the odor delivery system

There is currently a debate about the role played by temporal patterns in neural activity in olfactory coding. An accurate analysis of this question, however, is only possible if the temporal properties of a stimulus itself are well defined. So far, no technique with sufficient temporal resolution has been available to accomplish this. Using a photoionization detector (PID), we show that the configuration of the odor delivery apparatus and the airflow settings greatly influence the integrity of a stimulus profile within an odor delivery apparatus. In a situation where pulsatile odor stimuli are applied to a stationary preparation, we tested the effect of 1) axial and off-center location within the airstream, 2) airflow of the odor delivery, 3) exit tube length, 4) exit tube diameter, 5) orientation of the odor delivery device in relation to the exhaust flow, and 6) exhaust tube air speed. This has important implications for the study of time in olfaction; significant planning must be incorporated into the design of the experiment to provide a well-defined odor delivery system.     

The sniff is part of the olfactory percept

In this review, we use data obtained primarily from humans to argue that sniffs are not merely a stimulus carrier but are rather a central component of the olfactory percept. We argue that sniffs 1) are necessary for the olfactory percept, 2) affect odorant intensity perception and identity perception, 3) drive activity in olfactory cortex, 4) are rapidly modulated in an odorant-dependent fashion by a dedicated olfactomotor system, and 5) are sufficient to generate an olfactory percept of some sort even in the absence of odor.