Multimodal Stimulation of Colorado Potato Beetle Reveals Modulation of Pheromone Response by Yellow Light

Orientation of insects to host plants and conspecifics is the result of detection and integration of chemical and physical cues present in the environment. Sensory organs have evolved to be sensitive to important signals, providing neural input for higher order multimodal processing and behavioral output. Here we report experiments to determine decisions made by Colorado potato beetle (CPB), Leptinotarsa decemlineata, in response to isolated stimuli and multimodal combinations of signals on a locomotion compensator. Our results show that in complete darkness and in the absence of other stimuli, pheromonal stimulation increases attraction behavior of CPB as measured in oriented displacement and walking speed. However, orientation to the pheromone is abolished when presented with the alternative stimulation of a low intensity yellow light in a dark environment. The ability of the pheromone to stimulate these diurnal beetles in the dark in the absence of other stimuli is an unexpected but interesting observation. The predominance of the phototactic response over that to pheromone when low intensity lights were offered as choices seems to confirm the diurnal nature of the insect. The biological significance of the response to pheromone in the dark is unclear. The phototactic response will play a key role in elucidating multimodal stimulation in the host-finding process of CPB, and perhaps other insects. Such information might be exploited in the design of applications to attract and trap CPB for survey or control purposes and other insect pests using similar orientation mechanisms

Farmers’ perceptions of climate change : identifying types

Ambitious targets to reduce greenhouse gas (GHG) emissions from agriculture have been set by both national governments and their respective livestock sectors. We hypothesize that farmer self-identity influences their assessment of climate change and their willingness to im- plement measures which address the issue. Perceptions of climate change were determined from 286 beef/sheep farmers and evaluated using principal component analysis (PCA). The analysis elicits two components which evaluate identity (productivism and environmental responsibility), and two components which evaluate behavioral capacity to adopt mitigation and adaptation measures (awareness and risk perception). Subsequent Cluster Analyses reveal four farmer types based on the PCA scores. ‘The Productivist’ and ‘The Countryside Steward’ portray low levels of awareness of climate change, but differ in their motivation to adopt pro-environmental behavior. Conversely, both ‘The Environmentalist’ and ‘The Dejected’ score higher in their awareness of the issue. In addition, ‘The Dejected’ holds a high sense of perceived risk; however, their awareness is not conflated with an explicit understanding of agricultural GHG sources. With the exception of ‘The Environmentalist’, there is an evident disconnect between perceptions of agricultural emission sources and their contribution towards GHG emissions amongst all types. If such linkages are not con- ceptualized, it is unlikely that behavioral capacities will be realized. Effective communication channels which encour- age action should target farmers based on the groupings depicted. Therefore, understanding farmer types through the constructs used in this study can facilitate effective and tai- lored policy development and implementation

Plant odors as fruit fly attractants

Plant odors consist of a mixture of volatile compounds that are conveyed by diffusion through air and may disperse over a long distance. They play a major role in mediating insect-plant relationships, particularly food location and selection of suitable sites for mating or oviposition. This chapter presents state-of-the-art research on the response of fruit flies (Diptera, Tephritidae) to plant odors and their potential for the development of trapping systems. Main research results from Tephritids of economic importance (i.e., Rhagoletis, Ceratitis, Bactrocera/Dacus, and Anastrepha) show evidence of response to (i) general plant volatiles from host or non-host plants, the so-called 'green leaf volatiles', (ii) essential oils from host or non-host plants, and (iii) fruit odors (whole fruit, wounded or crushed fruit, extracts, etc.). Synergies between plant odors and food odors or sex pheromones are also addressed. Factors including insect physiology (age, mating status, egg load, etc.), experience (learning), and genetic background can substantially modify the response pattern to plant odors. One of the main challenges of using plant odors as fruit fly attractant is to improve the technology for identification (analysis), synthesis and emission (dispensers) of key compounds that may compete with natural volatile blends in the field. Further research should include the role of microorganisms in host location and recognition by fruit flies. Synthetic plant odors could be used either as kairomones for trapping systems, as allomones to push flies away from the crop or to disrupt host location, or as synomones to attract natural enemies to the crop. (Résumé d'auteur