Volatile compounds reveal age: a study of volatile organic compounds released by Chrysomya rufifacies immatures

Detailed chemical analysis of honey bee (Apis mellifera) worker brood volatile profile from egg to emergence

Chemical communication is a widely used mode of communication for social insects and has been demonstrated to be involved in many behaviours and physiological processes such as reproduction, nutrition or the fight against parasites and pathogens. In the honey bee, Apis mellifera, the release of chemical compounds by the brood plays a role in worker behaviour, physiology, and foraging activities and colony health as a whole. Several compounds have already been described as brood pheromones, such as components of the brood ester pheromone and (E)-β-ocimene. Several other compounds originating from diseased or varroa-infested brood cells have been described as triggering the hygienic behaviour of workers. So far, studies of brood emissions have focused on specific stages of development and little is known about the emission of volatile organic compounds by the brood. In this study, we investigate the semiochemical profile of worker honey bee brood during its whole developmental cycle, from egg to emergence, with a specific focus on volatile organic compounds. We describe variation in emissions of thirty-two volatile organic compounds between brood stages. We highlight candidate compounds that are particularly abundant in specific stages and discuss their potential biological significance.

Linking bacteria, volatiles and insects on carrion: the role of temporal and spatial factors regulating inter-kingdom communication via volatiles

Multi-kingdom community complexity and the chemically mediated dynamics between bacteria and insects have recently received increased attention in carrion research. However, the strength of these inter-kingdom interactions and the factors that regulate them are poorly studied. We used 75 piglet cadavers across three forest regions to survey the relationship between three actors (epinecrotic bacteria, volatile organic compounds (VOCs) and flies) during the first 4 days of decomposition and the factors that regulate this interdependence. The results showed a dynamic bacterial change during decomposition (temperature-time index) and across the forest management gradient, but not between regions. Similarly, VOC emission was dynamic across a temperature-time index and the forest management gradient but did not differ between regions. However, fly occurrence was dynamic across both space and time. The strong interdependence between the three actors was mainly regulated by the temperature-time index and the study regions, thereby revealing regulation at temporal and spatial scales. Additionally, the actor interdependence was stable across a gradient of forest management intensity. By combining different actors of decomposition, we have expanded our knowledge of the holistic mechanisms regulating carrion community dynamics and inter-kingdom interactions, an important precondition for better describing food web dynamics and entire ecosystem functions.

Diptera (Dryomyzidae, Fanniidae, Muscidae, Piophilidae) Associated With Pig Carcasses in a Forest Habitat of Poland: Sex-Related Patterns of Visitation and Effectiveness of Sampling Methods

Our knowledge on many necrophilous dipterans was limited for a long time mainly due to taxonomic issues. Therefore, findings on the sex-related associations with pig carcasses in Dryomyzidae, Fanniidae, Muscidae, and Piophilidae are presented. Moreover, the effectiveness of pitfall traps and sweep nets in fly sampling were compared, since the correct method of collecting insects is critical for the development and application of entomological tools for forensic purposes. The trapped numbers of all species differed significantly in respect to both sexes. The sex ratios were strongly female-biased in most species of Muscidae and in Fanniidae. More females were also collected in Piophilidae, but the proportion of males was higher when compared to muscids. Within Dryomyzidae, the sex ratio differed according to species. Only Dryomyza flaveola (Fabricius, 1794) (Diptera: Dryomyzidae) and Muscina pascuorum (Meigen, 1826) (Diptera: Muscidae) had male-biased sex ratios. Differences in residency patterns between sexes in Stearibia nigriceps (Meigen, 1826) (Diptera: Piophilidae), Liopiophila varipes (Meigen, 1830) (Diptera: Piophilidae), and D. flaveola were statistically insignificant. All studied species were recorded for each sampling method. The effect of the sampling method on the number of individuals was statistically significant for all dipterans but Piophilidae. Pitfall traps outcompeted the aerial sweep net in representing Dryomyzidae and Muscidae, whereas both methods were almost equally effective in the collection of Piophilidae. A varied effectiveness of sampling methods was observed in Fanniidae. The sampling method significantly affected the determination of the appearance time of flies on carcasses, but the effect of species and sampling method was insignificant. Implications for forensic entomology are discussed.