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Primer and releaser pheromones are molecules used for communication that induce species-specific responses. In contrast to primer pheromones, it is not known whether the quicker-acting releaser pheromones can affect brain gene expression. We show here that isopentyl acetate (IPA), a releaser pheromone that communicates alarm in honey bees, not only provokes a quick defensive response but also influences behavior for a longer period of time and affects brain gene expression. Exposure to IPA affected behavioral responsiveness to subsequent exposures to IPA and induced the expression of the immediate early gene and transcription factor c-Jun in the antennal lobes. Our findings blur the long-standing distinction between primer and releaser pheromone and highlight the pervasiveness of environmental regulation of brain gene expression.

Pheromones produce dramatic behavioral and physiological responses in a wide variety of species. Releaser pheromones elicit rapid responses within seconds or minutes, while primer pheromones produce long-term changes which may take days to manifest. Honeybee queen mandibular pheromone (QMP) elicits multiple distinct behavioral and physiological responses in worker bees, as both a releaser and primer, and thus produces responses on vastly different time scales. In this study, we demonstrate that releaser and primer responses to QMP can be uncoupled. First, treatment with the juvenile hormone analog methoprene leaves a releaser response (attraction to QMP) intact, but modulates QMP's primer effects on sucrose responsiveness. Secondly, two components of QMP (9-ODA and 9-HDA) do not elicit a releaser response (attraction) but are as effective as QMP at modulating a primer response, downregulation of foraging-related brain gene expression. These results suggest that different responses to a single pheromone may be produced via distinct pathways.

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a polyphagous pest native to East Asia and invasive in many countries. Various approaches have been used to control its spread, including IPM strategies. Monitoring pest populations is the starting point for developing an appropriate control strategy. The most common attractant for H. halys is based on its two-component aggregation pheromone ((3S,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol and (3R,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol), in combination with the synergist methyl (2E,4E,6Z)-2,4,6-decatrienoate. The aim of this research was to evaluate the most effective combination of the pheromone and the synergist for different types of adjuvants and dispensers, i.e., Blister Pack, Wax Tablet, and Polymers (Non-Biodegradable and Biodegradable Polymers). Field trials were carried out in Northern Italy, during summer and autumn 2023 and 2024. The effectiveness of the different combinations was evaluated on the basis of the number of H. halys individuals caught in sticky traps baited with the different treatments, separated by 50 m each. Individuals actively collected in the surrounding vegetation were also monitored. During the first year, the Non-Biodegradable Polymer performed better than the others. In the second year, H. halys captures were quite similar among the tested dispensers, and all were higher than the control. Captures of non-target stink bugs and other bugs of the Coreidae family were evaluated but, in most cases, were negligible. Under laboratory conditions, the release rate of the chemical compounds differed depending on the type of dispenser. Our results confirm the specificity of the semiochemical lure combination tested towards H. halys and its persistence in the field for at least 12 weeks. The results could be useful for improving the effectiveness of H. halys trapping, as well as for attract-and-kill or push–pull strategies of the pest.

An essential first step to implement a control strategy against herbivorous insects is the monitoring of their populations. The efficacy of pheromone-based traps in capturing herbivorous insects can be enhanced by adding adjuvants and using slow-release dispensers to ensure long-lasting attractiveness. Here, we present datasets from a two-year field monitoring campaign of the invasive brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), using clear sticky traps baited with its aggregation pheromone and a synergist, tested towards different dispensers and adjuvants. Bycatch data for native stink bugs (all Hemiptera: Pentatomidae) and leaf-footed bugs (Hemiptera: Coreidae) are also presented. The R code provided was used to organize data and generate weekly captures or weekly density of both H. halys and non-target species. The information provided in this article may contribute to the optimization of pest control strategies in agriculture.

The influence of pheromones on insect physiology and behavior has been thoroughly reported for numerous aspects, such as attraction, gland development, aggregation, mate and kin recognition. Brood pheromone (BP) is released by honey bee larvae to indicate their protein requirements to the colony. Although BP is known to modulate pollen and protein consumption, which in turn can affect physiological and morphological parameters, such as hypopharyngeal gland (HPG) development and ovarian activation, few studies have focused on the effect of BP on nutritional balance. In this study, we exposed newly emerged worker bees for 14 d and found that BP exposure increased protein intake during the first few days, with a peak in consumption at day four following exposure. BP exposure decreased survival of caged honey bees, but did not affect either the size of the HPG acini or ovarian activation stage. The uncoupling of the BP releaser effect, facilitated by working under controlled conditions, and the presence of larvae as stimulating cues are discussed.

The largemouth bass Micropterus salmoides (Lacépède, 1802) is a highly invasive freshwater species, and has a considerable impact on the diversity of indigenous aquatic organisms. We hypothesized that mature males released sex pheromones to attract mature females to their nests. To develop an effective method for controlling the population in a lake of northern Japan, we studied the efficacy of using bile collected from mature males with the bioactive function to attract mature females. A trap was devised to evaluate the attraction of sample solutions from males and to test practical uses of the pheromone. In the spawning season, when bile from reproductive males (RB) was introduced into the traps, female catches in the trap were significantly higher than when bile from non-reproductive males (NRB) or controls were used. In the non-spawning season, the female largemouth bass did not show any preference for RB. Other fish species did not show any preference for RB in both the spawning and non-spawning season. This study shows that RB contains a sex pheromone that attracts mature females, suggesting that pheromone traps could possibly be used to control largemouth bass populations.

The European shore crab Carcinus maenas is considered to rely on a female pheromone when mating. Evidence, however, is scarce on how the urine pheromone in itself affects males. We investigated male primer and releaser responses to female pheromones with methods that minimized effects from females, delivering female urine either as a pump-generated plume or deposited on a polyurethane sponge. We delivered the pheromone at different concentrations in far, near, and close/contact range to get a picture of how distance affects behavioral response. Our results show that substances in premolt female urine (PMU) function as primer and potent short-range releaser pheromones. Based on the olfactometer and sponge tests, we conclude that PMU stimulus in itself is sufficient to elicit increased search and mating-specific behaviors such as posing, posing search, cradle carrying, and stroking. Pheromone concentrations do not seem to be important for attenuating search and posing as long as the level is above a certain threshold concentration. Instead, pheromone levels seem to play a role in male acceptance of females, recruiting more males to respond, and generating better responses with increasing concentration.