Besides supporting cattle feeding, grasslands are home to a diversity of plants and insects that interact with each other by emitting volatile compounds. The aim of this work was to develop a method to determine permanent grassland odorscape and relate it to flower-visiting insects. Two grasslands were chosen for their contrasting levels of botanical diversity, resulting from differing grazing managements. Measurements were made over two periods of three consecutive days at the beginning of grazing, and just after the cows had left the plots. Volatile compounds were trapped using solid-phase microextraction (SPME) fibers exposed eight hours a day in three exclosures per plot, and then analyzed by gas-chromatography-mass spectrometry (GC-MS). Insects were trapped using pan traps and a net, sorted and counted. The open air SPME method yielded volatile compound profiles that were richer than maize field profiles, comprising the common green leaf volatiles (GLV) and more specific ones. Differences between the odorscapes of the two grasslands were found, but they were not as marked as expected from their botanical composition. By contrast, there were sharp differences between the two periods, resulting from the combined effects of changes in weather conditions, plant phenological stage and grazing progress. Several correlations between insect counts and volatile compounds were found. Although their correlation coefficients were low, some of them were confirmed when tested by Spearman rank correlation, and could be logically explained. This method of grassland odorscape deserves to be developed because it can provide information on many aspects of grassland function and on the stresses that grassland plants undergo.

Laboratory and field investigations to identify and evaluate plant co-attractants of the aggregation pheromone of the date palm pest Oryctes agamemnon are reported. Volatiles emitted by freshly cut palm core and palm core with feeding males, were collected, analyzed by gas chromatography coupled to mass spectrometry and evaluated in olfactometers alone or combined with synthetic pheromone. A collection of palm odor without male effluvia was attractive alone and enhanced attraction to synthetic pheromone in an olfactometer similar to that to a collection of palm odor emitted with feeding males and containing natural pheromone. Behavioral responses to collections of palm volatiles were correlated to the amount of volatiles material in them. Enhancement of the attractiveness of the pheromone was not correlated to chemicals specific to beetle feeding. The chemicals common to the active collections extracts were benzoate esters, mostly ethyl benzoate, anisole derivatives and sesquiterpenes. Blends of the most abundant components of the extracts were evaluated for enhancement of the attractiveness of pheromone (1 μg) in olfactometers at 1 or 10 μg doses. The mixtures were further evaluated by field trapping in Tunisia at 3-10 mg/day using reference (6 mg/day) or experimental pheromone formulations. A mixture of ethyl benzoate, 4-methylanisole and farnesol (1:1:1 w/w at 6.5 mg/day) enhanced captures in pheromone baited traps in 2014 and 2015 and this mixture was as active as the natural palm bait. The practical prospect of the result for the management for O. agamemnon, and other palm beetles is discussed.

Courtship behavior in several pyralid species is associated with the exposure to male hair pencils (HPs) or special scales that released volatile compounds. HP chemicals induce conspecific female and/or male behaviors and are therefore qualified as male pheromones. Preliminary observation on the coffee berry moth (CBM), Prophantis smaragdina Butler (Lepidoptera: Crambidae: Spilomelinae) mating behavior showed that the male displays abdominal HPs located on the last abdominal segment. The aim of the study was to identify the male volatile compounds and assess the results by electroantennography (EAG) on male and female antennae. Gas chromatography coupled to mass spectrometry analysis of male HP emissions showed five aromatic compounds identified as phenylacetaldehyde, phenylethyl alcohol, creosol, perillyl alcohol, and methyl anthranilate. EAG results showed that creosol elicited a significantly higher response than the control (hexane) on both male and female antennas. On female antennas, response to methyl anthranilate and phenylacetaldehyde was also significantly higher than the response to the control. Those results suggest that the creosol could play a behavioral role on conspecific male and female CBM during courtship behavior and mating choice. Methyl anthranilate and phenylacetaldehyde could also play a role on female behavior. Perillyl alcohol is for the first time identified as an insect product.

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