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Part of Chesterton’s imagery that he often employs in his writing is the motif of light and darkness, which in The Ball and the Cross takes the form of the cycle of night and day. This cycle dictates a specific rhythm, which rules over both the ongoing duel and other events. Thus, the evening and night time is rather reserved for considerable and profound insights, found in, for instance, the opening and closing scenes and in all the events that reflect or decide about the characters’ spiritual growth. The day time seems to contribute more to the development of the protagonists’ relationship with each other and the world around.

Neuropeptides of short neuropeptides F family (sNPF) have been identified in various arthropods. They are pleiotropic neuromolecules which so far have been mainly associated with regulation of feeding and metabolism, as well as growth and development, locomotion, circadian rhythm or learning and memory. Here, we describe the effects of Tenebrionid sNPF peptide (SGRSPSLRLRFa) on various aspects of the male reproductive physiology in the Tenebrio molitor beetle. We identified in silico the putative sNPF receptor Tenmo-sNPFR. Based on RT-PCR technique, it was shown that the receptor might be present in the male reproductive tissues of this beetle. The analysis of receptor amino acid sequence showed that it is similar to other beetle sNPFRs, as well as other insect species, and belongs rhodopsin-like G-protein-coupled receptors (GPCRs). Injections of Trica-sNPF and its shorter form Trica-sNPF(4–11) caused differentiated effects in T. molitor male reproductive tissues. After 24 h post injections, the peptides decreased the concentration of the soluble protein fraction in testes of 4- and 8-day-old beetles as well as the dry mass of these organs but only in 8-day-old individuals. The same effects were shown with regard to accessory glands. Both peptides decrease the concentration of the soluble protein fraction but do not affect the dry mass of this organ. Furthermore, injections of Trica-sNPF at the 10–7 M concentration decrease the total sperm number in the reproductive system. Surprisingly, the same concentration of the shorter form, Trica-sNPF(4–11) increased the sperm number. It was also shown that both peptides in different manner influence contractions of ejaculatory duct. The data presented in this article give new evidence that sNPFs are involved in the regulation of reproductive events in beetles, which might be the part of a larger neuropeptide network combining feeding, growth and development with the physiology of reproduction. Electronic supplementary material The online version of this article (10.1007/s00360-020-01296-z) contains supplementary material, which is available to authorized users.

Insect sulfakinins are pleiotropic neuropeptides with the homology to vertebrate gastrin/cholecystokinin peptide family. They have been identified in many insect species and affect different metabolic processes. They have a strong influence on feeding and digestion as well as on carbohydrate and lipid processing. Our study reveals that sulfakinins influence fatty acids composition in Zophobas atratus oenocytes and regulate insulin-like peptides (ILPs) level in these cells. Oenocytes are cells responsible for maintenance of the body homeostasis and have an important role in the regulation of intermediary metabolism, especially of lipids. To analyze the lipid composition in oenocytes after sulfakinins injections we used gas chromatography combined with mass spectrometry and for ILPs level determination an immunoenzymatic test was used. Because sulfakinin peptides and their receptors are the main components of sulfakinin signaling, we also analyzed the presence of sulfakinin receptor transcript (SKR2) in insect tissues. We have identified for the first time the sulfakinin receptor transcript (SKR2) in insect oenocytes and found its distribution more widespread in the peripheral tissues (gut, fat body and haemolymph) as well as in the nervous and neuro-endocrine systems (brain, ventral nerve cord, corpora cardiaca/corpora allata CC/CA) of Z. atratus larvae. The presence of sulfakinin receptor transcript (SKR2) in oenocytes suggests that observed effects on oenocytes lipid and ILPs content may result from direction action of these peptides on oenocytes.

Sperm motility is linked to the activation of signaling pathways that trigger movement. These pathways are mainly dependent on Ca2+, which acts as a secondary messenger. The maintenance of adequate Ca2+ concentrations is possible thanks to proper concentrations of other ions, such as K+ and Na+, among others, that modulate plasma membrane potential and the intracellular pH. Like in every cell, ion homeostasis in spermatozoa is ensured by a vast spectrum of ion channels supported by the work of ion pumps and transporters. To achieve success in fertilization, sperm ion channels have to be sensitive to various external and internal factors. This sensitivity is provided by specific channel structures. In addition, novel sperm-specific channels or isoforms have been found with compositions that increase the chance of fertilization. Notably, the most significant sperm ion channel is the cation channel of sperm (CatSper), which is a sperm-specific Ca2+ channel required for the hyperactivation of sperm motility. The role of other ion channels in the spermatozoa, such as voltage-gated Ca2+ channels (VGCCs), Ca2+-activated Cl-channels (CaCCs), SLO K+ channels or voltage-gated H+ channels (VGHCs), is to ensure the activation and modulation of CatSper. As the activation of sperm motility differs among metazoa, different ion channels may participate; however, knowledge regarding these channels is still scarce. In the present review, the roles and structures of the most important known ion channels are described in regard to regulation of sperm motility in animals.

Synthetic insecticides are widely used for crop protection both in the fields and in the food stored facilities. Due to their toxicity, and assumptions of Integrated Pest Management, we conducted two independent experiments, where we studied the influence of Solanum nigrum unripe fruit extract on the toxicity of an organophosphorus insecticide fenitrothion. In the first variant of the experiment, Tenebrio molitor larvae were fed with blended fenitrothion (LC50) and the extract in four concentrations (0.01, 0.1, 1 and 10%) in ratio 1:1 for 3 days. In the second variant, a two-day application of fenitrothion (LC40) was preceded by a one-day extract treatment. The first variant did not show any increase in lethality compared to fenitrothion, however, ultrastructure observations exhibited swollen endoplasmic reticulum (ER) membranes in the midgut and nuclear and cellular membranes in the fat body, after application of blended fenitrothion and extract. An increased amount of heterochromatin in the fat body was observed, too. In the second variant, pre-treatment of the extract increased the lethality of larvae, decreased the level of glycogen and lipids in the fat body and disrupted integrity of midgut cellular membranes. S. nigrum extract, applied prior to fenitrothion treatment can be a factor increasing fenitrothion toxicity in T. molitor larvae. Thus, this strategy may lead to decreased emission of synthetic insecticides to the environment.

Plant-derived substances, because of high biological activity, arouse interest of many scientists. Thus, plant extracts and pure substances are intensively studied on various insects as potential insecticides. In such studies, D. melanogaster is one of the most important model organisms. In our studies, we analysed the contents of two plant extracts and tested the activity of their main components against fruit flies and compared observed effects to effects caused by crude extracts. Then, we assessed the development of the next, unexposed generation. The chemical analysis of extracts revealed the presence of numerous glycoalkaloids and glucosinolates in Solanum nigrum and Armoracia rusticana extracts. These extracts, as well as their main components, revealed lethal and sublethal effects, such as the altered developmental time of various life stages and malformations of imagoes. Interestingly, the results for the extracts and pure main compounds often varied. Some of the results were also observed in the unexposed generation. These results confirm that the tested plants produce a range of substances with potential insecticidal effects. The different effects of extracts and pure main components suggest the presence of minor compounds, which should be tested as insecticides.

Plants are sources of numerous active substances that are used to protect crops. Currently, due to the limitations of using synthetic insecticides, plant products have attracted increasing attention as possible pesticides. In this review, we discuss some of the most interesting plant products (for example, Solanaceae, or Asteraceae extracts, Artemisia absinthium or Citrus spp. essential oils, and single compounds like α-chaconine, or α-solanine) that exhibit insecticidal activity against beetles that are pests of stored food products. Next, we describe and discuss the mode of action of these products, including lethal and sublethal effects, such as antifeedant or neurotoxic activity, ultrastructural malformation, and effects on prooxidant/antioxidant balance. Furthermore, the methods of application of plant-derived substances in food storage areas are presented.

Glycoalkaloids, secondary metabolites abundant in plants belonging to the Solanaceae family, may affect the physiology of insect pests. This paper presents original results dealing with the influence of a crude extract obtained from Solanum nigrum unripe berries and its main constituent, solasonine, on the physiology of Galleria mellonella (Lepidoptera) that can be used as an alternative bioinsecticide. G. mellonella IV instar larvae were treated with S. nigrum extract and solasonine at different concentrations. The effects of extract and solasonine were evaluated analyzing changes in carbohydrate and amino acid composition in hemolymph by RP-HPLC and in the ultrastructure of the fat body cells by TEM. Both extract and solasonine changed the level of hemolymph metabolites and the ultrastructure of the fat body and the midgut cells. In particular, the extract increased the erythritol level in the hemolymph compared to control, enlarged the intracellular space in fat body cells, and decreased cytoplasm and lipid droplets electron density. The solasonine, tested with three concentrations, caused the decrease of cytoplasm electron density in both fat body and midgut cells. Obtained results highlighted the disturbance of the midgut and the fat body due to glycoalkaloids and the potential role of hemolymph ingredients in its detoxification. These findings suggest a possible application of glycoalkaloids as a natural insecticide in the pest control of G. mellonella larvae.

Beet Armyworm, Spodoptera exigua is a herbivorous moth and a serious pest of many economically important plants, which are used as food sources. Because of rigorous standards of food quality, usage of synthetic insecticides in crop protection, against pests, is limited. Solanaceae plant extracts may be a relatively cheap source of efficient natural insecticides that can limit usage of synthetic substances. Their biological activity is not fully known. In particular, ultrastructural studies, using transmission electron microscopy, are not usual. In the present article we describe the effects of sublethal concentrations of tomato and potato leaf extracts against S. exigua. Acute lethal effects were not observed. Both extracts exerted similar effects within midgut and fat body cells. Midgut cells were not significantly altered while fat body cells showed prominent swelling of nuclear envelope and endoplasmic reticulum, vacuolization of mitochondria and fusion of fat droplets. These changes were much more intensive within groups exposed to potato than tomato extracts at highest concentration at least. Light microscopy was used to observe and document developmental alterations of S. exigua exposed to potato and tomato leaf extracts. Potato leaf extracts significantly decreased hatching success and caused morphological malformations of imagoes. Among them, malformations of wings were the most prominent. Interestingly, these effects were not observed within populations exposed to tomato extracts at highest concentration at least.

Background: Solanaceae plants produce glycoalkaloids (GAs) that affect various physiological processes of herbivorous insects and they are being tested as potential alternatives for synthetic pesticides. They cause lethal and sublethal effects. Nevertheless, their mode of action remains unclear. Therefore, we examined the effects of Solanum nigrum fruit extracts and pure glycoalkaloids on a model beetle, Tenebrio molitor. Methods: Plant extracts or pure alkaloids were added to the food of the larvae for three days. The lipid, glycogen, and protein content in the fat body and the midgut were determined, and the contractility of the heart, hindgut, and oviduct muscles was tested using the video-microscopy technique. Finally, the ultrastructure of the fat body and the midgut was observed using electron microscopy. Results: No lethal effects were noted. Sublethal changes were observed in the content of biomolecules, malformations of organelles, chromatin condensation, and heart and oviduct contractility. The observed effects differed between the tested glycoalkaloids and the extract. Conclusions: Both the extract and pure GAs have a wide range of effects that may result in impaired development, food intake, and reproduction. Some early effects may be used as bioindicators of stress. The effects of the extract and pure alkaloids suggest that the substances produced by the plant may act additively or synergistically.

Model organisms are often used in biological, medical and environmental research. Among insects, Drosophila melanogaster, Galleria mellonella, Apis mellifera, Bombyx mori, Periplaneta americana, and Locusta migratoria are often used. However, new model organisms still appear. In recent years, an increasing number of insect species has been suggested as model organisms in life sciences research due to their worldwide distribution and environmental significance, the possibility of extrapolating research studies to vertebrates and the relatively low cost of rearing. Beetles are the largest insect order, with their representative - Tribolium castaneum - being the first species with a completely sequenced genome, and seem to be emerging as new potential candidates for model organisms in various studies. Apart from T. castaneum, additional species representing various Coleoptera families, such as Nicrophorus vespilloides, Leptinotarsa decemlineata, Coccinella septempunctata, Poecilus cupreus, Tenebrio molitor and many others, have been used. They are increasingly often included in two major research aspects: biomedical and environmental studies. Biomedical studies focus mainly on unraveling mechanisms of basic life processes, such as feeding, neurotransmission or activity of the immune system, as well as on elucidating the mechanism of different diseases (neurodegenerative, cardiovascular, metabolic, or immunological) using beetles as models. Furthermore, pharmacological bioassays for testing novel biologically active substances in beetles have also been developed. It should be emphasized that beetles are a source of compounds with potential antimicrobial and anticancer activity. Environmental-based studies focus mainly on the development and testing of new potential pesticides of both chemical and natural origin. Additionally, beetles are used as food or for their valuable supplements. Different beetle families are also used as bioindicators. Another important research area using beetles as models is behavioral ecology studies, for instance, parental care. In this paper, we review the current knowledge regarding beetles as model organisms and their practical application in various fields of life science.

Plants are sources of numerous active substances that are used to protect crops. Currently, due to the limitations of using synthetic insecticides, plant products have attracted increasing attention as possible pesticides. In this review, we discuss some of the most interesting plant products (for example, Solanaceae, or Asteraceae extracts, Artemisia absinthium or Citrus spp. essential oils, and single compounds like α-chaconine, or α-solanine) that exhibit insecticidal activity against beetles that are pests of stored food products. Next, we describe and discuss the mode of action of these products, including lethal and sublethal effects, such as antifeedant or neurotoxic activity, ultrastructural malformation, and effects on prooxidant/antioxidant balance. Furthermore, the methods of application of plant-derived substances in food storage areas are presented.

Insects are the largest and the most widely distributed group of animals in the world. Their diversity gives rise to an incredible variety of different mechanisms for the regulation of life processes. There are many agents that regulate immunology, reproduction, growth and development or metabolism. Hence, it seems that insects may be a source of numerous substances with utility for the treatment human diseases. Of particular importance in the regulation of insect physiology are peptides, including neuropeptides, peptide hormones and antimicrobial peptides. There are two main ways in which these peptides may be useful. 1) Peptides isolated from insects may become potential therapeutic drugs for different diseases. 2) Many insect peptide hormones show structural or functional homology to mammalian peptide hormones, and comparative studies may provide a new perspective on human disorders. In our review, we focused on three groups of insect-derived peptides: 1) immune-active peptides, 2) peptide hormones and 3) peptides present in venoms. In our review, we show the considerable potential of insect peptides in the search for new solutions for mammalian diseases treatment. We summarize knowledge about the properties of insect peptides against different virulent agents, and their anti-inflammatory or anti-nociceptive properties as well as compare the insect and mammalian/vertebrate peptide endocrine systems to determine the usefulness of knowledge about insect peptide hormones in drug design. The field of possible uses of insect-delivered peptides for the treatment of various human diseases has still not been sufficiently explored. Undoubtedly, more attention should be paid to insects in the search for new drugs.

MALDI-TOF MS and MS/MS techniques were used for the isolation and identification of neuropeptides from the ventral nerve cord (VNC) of two beetle species Tenebrio molitor and Zophobas atratus. Two peptides, proctolin and myosuppressin (Zopat-MS), with well-established myotropic properties were identified as well as Trica-NVPL-4trunc. The presence of proctolin and myosuppressin was confirmed by immunocytochemical studies in adults and larvae of both beetles. In addition, the myosuppressin gene in Z. atratus was sequenced and expression analyses showed that it is present in all parts of the beetle central nervous system. Results suggest that the identified peptides act as neurotransmitters/neuromodulators in beetles, regulate visceral muscle contractions and indirectly influence important physiological processes such as feeding and reproduction.

Effects of Led-NPF-I peptide hormone (Ala-Arg-Gly-Pro-Gln-Leu-Arg-Leu-Arg-Phe-amide) and its analogues were tested on the contractile activity of the oviduct of two beetle species Tenebrio molitor and Zophobas atratus. The influence of Led-NPF-I on the developmental processes of T. molitor was also examined. The unmodified Led-NPF-I molecule exerts inhibitory effects on contractions of the oviduct in both beetles; however, the efficiency of inhibition was stronger in T. molitor females. Structure–activity studies showed that replacement of Arg residue in positions 2, 7 and 9 in the amino acid sequence by His, D-Arg or Lys led to changes in myoinhibitory properties of almost all of the analogues in both species. In the majority of the analogues, the effect was weaker when compared to the native molecule. In the developmental bioassays, injections of Led-NPF-I peptide delayed the moulting process of T. molitor larvae and accelerated pupal moult. It also increased the growth in pre-starved and non-starved la...

Beet Armyworm, Spodoptera exigua is a herbivorous moth and a serious pest of many economically important plants, which are used as food sources. Because of rigorous standards of food quality, usage of synthetic insecticides in crop protection, against pests, is limited. Solanaceae plant extracts may be a relatively cheap source of efficient natural insecticides that can limit usage of synthetic substances. Their biological activity is not fully known. In particular, ultrastructural studies, using transmission electron microscopy, are not usual. In the present article we describe the effects of sublethal concentrations of tomato and potato leaf extracts against S. exigua. Acute lethal effects were not observed. Both extracts exerted similar effects within midgut and fat body cells. Midgut cells were not significantly altered while fat body cells showed prominent swelling of nuclear envelope and endoplasmic reticulum, vacuolization of mitochondria and fusion of fat droplets. These changes were much more intensive within groups exposed to potato than tomato extracts at highest concentration at least. Light microscopy was used to observe and document developmental alterations of S. exigua exposed to potato and tomato leaf extracts. Potato leaf extracts significantly decreased hatching success and caused morphological malformations of imagoes. Among them, malformations of wings were the most prominent. Interestingly, these effects were not observed within populations exposed to tomato extracts at highest concentration at least.

In insects, the majority of studies have been conducted on the hormonal regulation of female reproduction. Thus far, little is known about the regulation of male reproductive physiology, especially by peptide hormones. We report here, for the first time in insects, the effects of three peptides, Neb-colloostatin (SIVPLGLPVPIGPIVVGPR), Neb-TMOF (NPTNLH) and Lepde-NPF-I (ARGPQLRLRFa), on various aspects of reproduction in male Tenebrio molitor beetles. All three tested peptides increased the soluble protein concentration in the testes and the dry mass of the beetle's testes. They also significantly changed the protein profiles of the testes. Injection of these peptides also significantly changed the number of sperm cells in the testes. However, the observed effects were age specific. The most prominent changes were observed in 4-day-old males. Neb-colloostatin and Neb-TMOF decreased the number of sperm cells, whereas Lepde-NPF-I increased the number of spermatocytes. Moreover, in vitro experiments revealed that Neb-TMOF and Lepde-NPF-I increased the contractility of the ejaculatory duct of T. molitor males. The results obtained suggest that different reproductive processes in males might be regulated by complex mechanisms.

The physiological processes that occur during the aging of insects are poorly understood. The aim of this study was to describe the changes in contractile activity and hemodynamic parameters of the heart that take place as the coleopteran beetle, Tenebrio molitor, ages. The frequency of heart contractions in beetles that had just undergone metamorphosis (median 24.7 beats/min) was significantly lower than the frequency of heart contractions in older beetles. In 56% of beetles that were

Peptides from the pyrokinin (PK) family are a large, structurally and functionally diverse group of the insect neuropeptides produced by neurosecretory cells of the insect nervous system. This family contains short and long peptides which share C-terminal -FXPRLa amino acid sequence. Pyrokinins regulate the visceral muscle contractions, pheromone biosynthesis, pupariation and diapause duration in insects. They are encoded by two genes PBAN and capa, which are mainly expressed in the suboesophageal ganglion. Peptides are then transported to the retrocerebral complex and released into haemolymph. Recent studies are focused on application of pyrokinins as biopesticides in the regulation of insect pests growth and development.

Pyrokinins are a large family of insect neuropeptides exhibiting pleiotropic activity, but are predominantly myostimulatory hormones. In this study, four pyrokinins Tenmo-PK-1 (HVVNFTPRLa), Tenmo-PK-2 (SPPFAPRLa), Tenmo-PK-3 (HLSPFSPRLa) and Zopat-PK-1 (LPHYPRLa) from the neuro-endocrine system of two tenebrionid beetles, Tenebrio molitor and Zophobas atratus, were tested in homologous bioassays to evaluate their putative myotropic and glycaemic actions. The four investigated bioassays systems (the heart, oviduct, ejaculatory duct and hindgut) revealed species-specific and organ-specific myotropic actions for the pyrokinins tested. In most bioassays with both beetles, the peptides showed myostimulatory properties with different efficacy. However, the T. molitor heart is not sensitive to Tenmo-PK-1, Tenmo-PK-2 and Tenmo-PK-3, and one of the peptides Tenmo-PK-1, is myoinhibitory on the oviduct. Tenmo-PK-2, which is also present in Z. atratus, exerted an inhibitory effect on the contractions of the heart and ejaculatory duct muscles in this beetle. Such myoinhibitory properties of pyrokinins in insects are shown here for the first time. Only one of the peptides tested, Tenmo-PK-2, stimulated a hyperglycaemic response in the haemolymph of larvae of T. molitor and Z. atratus, and this effect suggests a possible additional metabotropic function of this peptide in beetles. The differences in the myotropic and glycaemic responses to pyrokinins suggest that these peptides modulate contractions of muscles from visceral organs and free sugar levels in the haemolymph of the beetles, through complex and species-specific mechanisms.

Essential role in the regulation of all physiological processes and maintenance of homeostasis in the vast majority of animal organisms plays a neuro- endocrine system. So far, very well known to features are neuro-hormonal mediators regulating life processes of human. Over the last decade attention of researches has focused on identification and evaluation functions of insect neuropeptides and genes encoding them. In the present review, the structure and functions of insect neuro-endocrine system are characterized, the current state of knowledge on the difficulties and strategies in the neuropeptidomics research of these animals, with special emphasis on the use of mass spectrometry and the current rules of neuropeptides classification. Moreover, a list of known neuropeptidome insect species is presented, functional similarities between insect neuropeptides and their homologues occurring in vertebrates are defined and potential applications of research in the field of neuropeptidomics ewaluated. Available literature data suggest that neuropeptides so far identified in the insect model organism such as Drosophila melanogaster, may be used in the future to design a new generation of pharmaceuticals and bioinsecticides limiting the number of harmful insects from medical and economic point of view.