Insects are traditionally thought to respond to noxious stimuli in an inflexible manner, without the ability to modulate their behavior according to context. We investigated whether bumblebees’ attraction to high sucrose solution concentrations reduces their avoidance of noxious heat. Bees were given the choice between either unheated or noxiously heated (55 °C) feeders with different sucrose concentrations and marked by different colors. Bees avoided noxious feeders when the unheated feeders contained high sucrose concentrations, but progressively increased feeding from noxious feeders when the sucrose concentration at unheated feeders decreased. This shows a motivational trade-off of nociceptive responses. Bees used learned color cues for their decisions, and thus the trade-off was based on processing in the brain, rather than just peripheral processing. Therefore, bees can use contextual information to modulate nociceptive behavior. This ability is consistent with a capacity for pain experiences in insects.

This study explores the influence of rosemary, Rosmarinus officinalis (L.) essential oil (EO) on the biochemical (acetylcholinesterase, catalase, and glutathione S-transferase), physiological (oxygen consumption), and behavioral (open field test, repellency) parameters of an important stored product insect: cowpea weevil, Callosobruchus maculatus (F.). R. officinalis EO exhibited effective insecticidal action against C. maculatus even at relatively low concentrations. LC₅₀ = 15.69 μL/L air, and was highly repellent at concentrations equal to or above LC₂₅. Statistically significant inhibition in locomotor activity occurred only after the acute exposure to the EO at LC_12.5 and LC₂₅. The oxygen consumption test showed metabolism increase only at LC₅₀. An increase in activity was observed in the case of all three enzymes examined. The presented data provides a potentially valuable resource in designing more environmentally friendly and safer insecticide agents.

The main aim of the presented paper is to assess the potential repellent effect of selected essential oils (EOs) against the lesser mealworm (Alphitobius diaperinus), which can cause economic losses in storage and in the poultry industry. Due to the development of pesticide resistance in A. diaperinus populations, as well as an attempt to limit extensive use of potentially harmful pesticides in food-related industries, there is a strong need for the development of alternative methods of dealing with A. diaperinus infestations. Because of their cost-effectiveness, availability and low vertebrate toxicity, EOs are promising agents in pest management. In the presented paper four off-the-shelf EOs: mint, vanilla, lemon and citronella (and mixtures of them) were tested as potential repellents. Moreover, a novel preference assay, providing an extended analysis of the preference and the locomotor response, was used. The most effective EOs were: citronella and lemon. EOs mixtures were generally more repellent than individual EOs, with the lemon and vanilla 1:1 mixture acting as the strongest repellent. A few of the tested EOs caused significant alterations to the locomotor activity, although no direct relation was observed. In conclusion, EOs can be potentially used as repellent agents in A. diaperinus management. Additionally, data on the locomotor activity may lead to designing better push-pull strategies in pest management.

The essential oils (EOs) are volatile plant extracts that are commonly considered as potential biopesticides. They present promising properties as relatively safe and potent insecticides, primarily delivered via fumigation. Such specificity of the EOs has led to the growing interest of researchers and, subsequently, to an increasing body of publications. The studies focusing on assessing the insecticidal action of EOs frequently require testing the effects of several dilutions of a given EO. To this end, researchers employ a range of solvents differing widely between the studies. While informative, the standardization concerning either tested oil or pest species is lacking in these studies. The presented study herein aimed to test whether the solvent used could affect the observed insecticidal activity of tested EO. As the model setup for studying the possible influence of solvents on the insecticidal effect of EOs, two EOs: mint and rosemary were chosen. The EOs were applied in fumigation assay against three economically important species of stored product pests: Callosobruchus maculatus, Sitophilus oryzae, and Tribolium castaneum. Each EO was tested in three concentrations—diluted with a range of solvents; dimethyl sulfoxide, acetone, methanol, ethanol, paraffin (mineral) oil, ultrapure water with 0.1% polysorbate 20 (TWEEN^® 20). The results confirm the hypothesis that the applied solvent could significantly alter the observed efficiency of tested EO. Such a result is of crucial value for conducting credible meta-analysis as well as for establishing a high standard of reproducibility.

The main scope of the presented paper is an assessment of the potential repellent effect of selected essential oils (EOs) against Alphitobius diaperinus, which can cause economic losses in storages and poultry industry. Due to development of pesticide resistance in A. diaperinus populations, as well as an attempt to limit extensive usage of potentially harmful pesticides in food-related industries, there is a strong need for development of alternative methods of management of A. diaperinus infestations. Because of cost-effectiveness, availability and low vertebrate toxicity EOs are promising agents in pest management. In presented paper four of-the-shelf EOs: mint, vanilla, lemon and citronella (and their mixtures) were tested as a potential repellents. Moreover, novel preference assay providing an extended analysis of preference and the locomotor response was used. The most effective EOs were, respectively: citronella and lemon. EOs mixtures were generally more repellent than single EOs, with lemon and vanilla 1:1 mixture acting as the strongest repellent. Few of tested EOs caused significant alterations in locomotor activity, although direct relation wasn’t observed. In conclusion, EOs can be potentially used as a repellent agents in A. diaperinus management. Additionally, data on locomotor activity may lead to better design of pull-push strategies in pest management.