The short-chain fatty acids as potential protective agents against Callosobruchus maculatus infestation

The cowpea weevil, Callosobruchus maculatus, is one of the most common pests of stored legumes. Its occurrence adversely affects the quality of stored beans, making them unfit for consumption, resulting in substantial financial losses. The aim of this study was to investigate the potential insecticidal properties of the volatile fatty acids (VFAs) (C1 – C5) and their influence on the insect’s physiology and behavior. All VFAs in concentrations equal to 4 μl and 8 μl showed fumigant toxicity significantly higher from the control. The strongest effect was observed in the case of propionic and valeric acid in volume of 4 μl and 8 μl, where mortality was close to 100%. Except for butyric acid, all acids showed a significant repellent effect. Additionally, all VFAs significantly decreased the number of infested beans and influenced the locomotor activity. Of all tested acids only the formic acid did not affect the oxygen consumption of the insects. As the studied VFAs have noteworthy properties against C. maculatus, they could be considered as promising agents in new strategies for stored products pest management

The role of dilution mediums in studies of fumigant insecticidal activity of essential oils

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 Effect of Rosmarinus officinalis Essential Oil Fumigation on Biochemical, Behavioral, and Physiological Parameters of Callosobruchus maculatus

This study explores the influence of rosemary, Rosmarinus o cinalis (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. o cinalis EO exhibited e ective insecticidal action against C. maculatus even at relatively low concentrations. LC50 = 15.69 L/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 LC12.5 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

Does spatial navigation have a blind-spot? Visiocentrism is not enough to explain the navigational behavior comprehensively

Preparation of the manuscript was supported by the research grant 2015/19/B/HS1/03310 “Mechanisms of geometric cognition” funded by National Science Centre, Poland.In this paper, we argue that the issues described arise not because of the lack of theoretical inspiration, but rather due to an insufficient understanding of the subtleties of insect behavior. In our view, implementation of the insects’ models of navigation in the explanation of the vertebrates’ spatial behavior omits some important aspects, i.e., multimodal integration. Thus, we want to ask again the initial question posed by Wystrach and Graham (2012b) pointing out that significant progress in insects’ research, which suggests that we might have had underestimated insects’ cognitive abilities (Loukola et al., 2017; Peng and Chittka, 2017). Those results demonstrated insects’ capacity to obtain abstract information from multimodal input during complex tasks. Movement through a real environment provides a variety of cues, not only visual ones, thus in the following article we argue that multimodal integration is crucial to navigation.National Science Centre, Polan

Intergenerational transmission of resistance of Callosobruchus maculatus to essential oil treatment

Due to the rise of numerous legal restrictions as well as the increasing emergence of resistant populations, the number of available pesticides is decreasing significantly. One of the potential alternatives often described in the literature are essential oils (EOs). However, there is a lack of research addressing the potential emergence of resistance to this group of substances. In this paper, we investigated the multi-generational effects of sublethal concentrations of rosemary oil (Rosmarinus officinalis) on physiological and biochemical parameters of the cowpea weevil (Callosobruchus maculatus) such as egg laying, hatchability, oxygen consumption and acetylcholinesterase activity. Imago, which as larvae were exposed to EO at concentrations equivalent to LC25, showed significantly lower mortality. The results obtained indicate the potential development of resistance in insects exposed to EO in concentrations corresponding to LC25. In addition, in the case of the group treated with an EO concentration corresponding to LC3.12, a stimulation effect of the above-mentioned parameters was observed, which may indicate the occurrence of a hormesis effect. The obtained results may be an important reference for the development of future guidelines and EO-based insecticides

Caffeine effects on AdoR mRNA expression in Drosophila melanogaster

In this study, we aimed to evaluate whether exposure to caffeine in the early stages of development affect AdoR mRNA expression levels in the fruit fly (Drosophila melanogaster) and how this will relate to the developmental success of flies. Adenosine receptors are seen as the most important biochemical targets of caffeine. Simultaneously adenosine signaling orchestrates the development and growth of insects. We demonstrate that AdoR mRNA expression in D. melanogaster is persistent from early stages till imago. Strong alterations in AdoR expression were observed in larvae that had been treated with caffeine. However, after the imaginal molt, the differences in AdoR expression between the insects from all of the test groups evened out despite a wide range of developmental success in the groups. Taken together, these results suggest that caffeine affects the expression of its cellular targets even from the early stages of fruit fly development and thus there is a significantly lower larvae-to-adult survival rate. Moreover, we also proved that the expression of AdoR undergoes a peculiar reset during the maturation of D. melanogaster despite the conditions in which larvae developed

Repellent effect of volatile fatty acids on lesser mealworm (Alphitobius diaperinus)

Volatile fatty acids (VFAs) are a group of common metabolites and semiochemicals mediating information transfer between higher organisms and bacteria, either from microbiome or external environment. VFAs commonly occur among various insect orders. There are numerous studies exploring their influence on the behavior of different insect species. In relation to the papers published by J. E. McFarlane in 1985, we assessed the effects of formic, acetic, propionic, butyric and valeric acids on the spatial preference of the lesser mealworm (Alphitobius diaperinus), a common pest of stored food grain products and the poultry industry. The main aim of the presented study was to provide new angles in VFA research, recreating the classical study both with new methods and on economically significant pest species. This paper presents a novel method of continuous, simultaneous assessment of site preference and the travelled distance in a constant-flow olfactometer. All the tested VFAs, except valeric acid, had a significant repellent effect, with formic acid being effective even at the lowest used concentration. Additionally, the VFAs significantly altered the distance travelled by the insects. The obtained results indicate a potential role for VFAs in the olfactory guided behavior of A. diaperinus. It is suspected that the reaction to the presence of VFAs may deviate from the specificity of species’ original habitat

Impact of synthetic polymers on the house cricket (Acheta domesticus) growth and development

tekst w j. pol. i ang.Celem eksperymentu było zbadanie potencjalnego oddziaływania polimerów formowanych termicznie w toku procesu drukowania 3D na wzrost, rozwój i przeżywalność świerszcza domowego. Granulat wydrukowany z filamentu akrylonitrylo-butadieno-styrenowego (ABS) w ilości odpowiadającej 0,1, 1 i 10% posłużył do przygotowania odpowiednio zanieczyszczonej wody podawanej następnie owadom (10-dniowe larwy) w trakcie ich rozwoju aż do osiągniecia przez nie stadium imago

The effects of high-monosaccharide diets on development and biochemical composition of white-eyed mutant strain of house cricket (Acheta domesticus)

Tryptophan (TRP) is one of the essential amino acids in the animal body. Its exogenicity and low concentrations mean that it can be regarded as one of the key regulatory molecules at the cellular as well as physiological level. It has been shown to have a number of essential functions, such as in the production of other biologically active molecules. The main objective of this project was to investigate the effects of a high monosaccharide diet (HMD) on a hemimetabolic insect-house cricket (Acheta domesticus) and a mutant strain with impaired visual pigment synthesis (closely related to the tryptophan and kynurenine (KYN) metabolic pathway)-white eye. This study was aimed at determining the effects of glucose and fructose on cricket development and biochemical composition. A parallel goal was to compare the response of both cricket strains to HMD. ELISA assays indicated dysfunction of the TRP-KYN pathway in white strain insects and an elevated KYN/TRP ratio. Biochemical analyses demonstrated the effects of HMD mainly on fat and glycogen content. A decrease in food intake was also observed in the groups on HMD. However, no changes in imago body weight and water content were observed. The results of the study indicate a stronger response of the white strain to HMD compared to the wild-type strain. At the same time, a stronger detrimental effect of fructose than of glucose was apparent. Sex was found to be a modulating factor in the response to HMD