Pharmacological properties of blister beetles (Coleoptera: Meloidae) promoted their integration into the cultural heritage of native rural Spain as inferred by vernacular names diversity, traditions, and mitochondrial DNA

Cantharidin: A Multiporpuse Beetlejuice

Cantharidin is produced by beetles of two families, Meloidae (true blister beetles) and Oedemeridae (false blister beetles). Nevertheless, it is mainly members of the meloid family that have been widely studied in the traditional medicines and pharmacology of different cultures and countries. The meloids cantharidin's role is going to be reviewed in this paper, including the cantharidin discovery, its adaptative function, and worldwide uses. Finally, we recovered information on the implementation of this compound in South American civilizations in different therapeutic treatments as well as sexual stimulants and aphrodisiacs.

Antiparasitic Effects of Potentially Toxic Beetles (Tenebrionidae and Meloidae) from Steppe Zones

Arthropods and specifically beetles can synthesize and/or sequester metabolites from dietary sources. In beetle families such as Tenebrionidae and Meloidae, a few studies have reported species with toxic defensive substances and antiparasitic properties that are consumed by birds. Here we have studied the antiparasitic activity of extracts from beetle species present in the habitat of the Great Bustard (Otis tarda) against four pathogen models (Aspergillus niger, Meloidogyne javanica, Hyalomma lusitanicum, and Trichomonas gallinae). The insect species extracted were Tentyria peiroleri, Scaurus uncinus, Blaps lethifera (Tenebrionidae), and Mylabris quadripunctata (Meloidae). M. quadripunctata exhibited potent activity against M. javanica and T. gallinae, while T. peiroleri exhibited moderate antiprotozoal activity. The chemical composition of the insect extracts was studied by gas chromatography coupled with mass spectrometry (GC-MS) analysis. The most abundant compounds in the four beetle extracts were hydrocarbons and fatty acids such as palmitic acid, myristic acid and methyl linoleate, which are characteristic of insect cuticles. The presence of cantharidin (CTD) in the M. quadripunctata meloid and ethyl oleate (EO) in T. peiroleri accounted for the bioactivity of their extracts.

Proctodeal extrusion as a defensive behavioral response in blister beetles (Coleoptera: Meloidae)

Defensive mechanisms in blister beetles (Coleoptera: Meloidae) include a wide variety of behavioral responses, chemical defense, and conspicuous external colorations. Although some of these mechanisms have been previously described, proctodeal extrusion, a defensive behavior involving the extrusion of inner abdominal membranes from the proctodeal region which appear intensely red or orange colored when the hemolymph is seen through them, has not been reported to date. Here, we tested the ability to display proctodeal extrusion in response to threat stimuli in wild populations of three blister beetle species inhabiting Central Spain: Berberomeloe majalis (Linnaeus, 1758), Berberomeloe comunero Sánchez-Vialas, García-París, Ruiz & Recuero, 2020, and Physomeloe corallifer (Germar, 1818). In addition, we observed and recorded various other defensive behaviors such as immobility, antennal threat display, autohemorrhage (reflex bleeding), defecation, and thanatosis (death feigning). The frequency at which proctodeal extrusion was observed differed among species, as did the stress intensity needed for extrusion and the probability of proctodeal extrusion in response to a particular threatening stimulus. Our findings indicate that, although proctodeal extrusion might be a widespread potential defensive mechanism in Meloidae, the ability to elicit it is not generalized across lineages. Physomeloe and Berberomeloe are endemic to the semi-arid Mediterranean region, and species adapted to such a climate would have developed strategies that limit hydric stress such as proctodeal extrusion, which mirrors the effect of autohemorrhage but without the fluid loss.

Entomotherapy: a study of medicinal insects of seven ethnic groups in Nagaland, North-East India

BACKGROUND

The ethnic communities in Nagaland have kept a close relationship with nature since time immemorial and have traditionally used different kinds of insects and their products as folk medicine to treat a variety of human ills and diseases. The present study was conducted to record the entomotherapeutic practices of seven different ethnic groups of Nagaland.

METHOD

Documentation is based on semi-structured questionnaires and group discussions with a total of 370 informants. The data collected were analysed using fidelity level (FL) and informant consensus factor (ICF).

RESULTS

Fifty species of medicinal insects belonging to 28 families and 11 orders were identified in connection with treatments of at least 50 human ailments, of which the most frequently cited were coughs, gastritis, rheumatoid arthritis, stomach ache and wound healing. Mylabris sp. showed the highest fidelity level (FL) of 100% for its therapeutic property as a dermatologic agent, while the informant consensus factor (ICF) ranged from 0.66 to 1.00. The use of medicinal insects varies amongst the seven ethnic groups, suggesting that differences in cultures and geographic location can lead to the selection of specific insect species for specific medicinal purposes. The largest number of insect species appear to be used for treating gastrointestinal, dermatological and respiratory diseases.

CONCLUSION

The list of medicinal insect species, many of which are reported for the first time in the present study, suggests the presence of a considerable diversity of therapeutically important insect species in the region and elaborate folk medicinal knowledge of the local ethnic groups. This knowledge of insects not just as a food, but also as therapy is passed down verbally from generation to generation, but is in danger of being lost if not documented in a systematic way. Having stood the test of time, traditional folk medicinal knowledge and its contribution through entomotherapy should not be regarded as useless as it has the potential to lead to the development of novel drugs and treatment methods.

Entomological Surveillance and Cantharidin Concentrations in Mylabris variabilis and Epicauta rufidorsum Blister Beetles in Slovenia

True blister beetles (genus Epicauta, family Meloidae) produce cantharidin, which can cause toxicosis in humans and animals. Some recent reports suggest that poisoning by the blister beetle has occurred in the Mediterranean part of Slovenia, which has never been reported before. Drought and modern harvesting techniques are thought to increase the likelihood of blister beetle forage contamination and cantharidin intoxication in animals. A survey of fields associated with blister beetle contamination was conducted and the Meloid species present were identified. Entomological surveillance was conducted for Mylabris variabilis and Epicauta rufidorsum. Cantharidin concentrations were also measured in both blister beetle species. Cantharidin concentration in Mylabris variabilis (n = 17) ranged from 0.038 to 0.354 µg/mg (mean 0.151 µg/mg). Cantharidin concentration in Epicauta rufidorsum (n = 36) ranged from 0.055 to 0.341 µg/mg (mean 0.142 µg/mg). Both species exhibited variable concentrations of cantharidin that could not be associated with their biology, sex, age, size, and/or reproductive status. Epicauta rufidorsum have never previously been studied as a possible source of forage contamination, nor have cantharidin concentrations been determined in this species. It is the most likely source of forage contamination due to its abundance in the investigated fields, its swarming activity, and its tendency to reside in the green parts of plants immediately after cutting. Delaying the simultaneous processing and storage of forage after cutting would reduce the likelihood of forage contamination by blister beetles, as they can then retreat to the ground or fly away.

Patterns of morphological diversification in giant Berberomeloe blister beetles (Coleoptera: Meloidae) reveal an unexpected taxonomic diversity concordant with mtDNA phylogenetic structure

Delimiting species boundaries is a complex challenge usually hindered by overlooked morphological diversification or misinterpretation of geographically structured phenotypic variability. Independent molecular data are extremely useful to characterize and understand such morphological diversity. Morphological and molecular variability of the non-phoretic and apterous, widely distributed, giant blister beetles of the genus Berberomeloe, were investigated within and between lineages across most of the distributional range of the genus. We used two mtDNA gene fragments to characterize genetic variability and to produce a time-calibrated phylogeny of the genus. Our results reveal several mitochondrial lineages, allopatrically, parapatrically and sympatrically distributed. Most clades are not distinguishable between each other based on morphometrics. However, no morphometric overlap is observed between two closely related clades, one of them occurring in sympatry with a distantly congeneric species (B. insignis), suggesting that sympatry could trigger morphological diversification. Although most species share a morphometric space, they can be morphologically identified by a combination of easily observed characteristic qualitative features. Based on the concordance between mtDNA clades and morphological units, we describe six new species of Berberomeloe (B. castuo sp. nov., B. comunero sp. nov., B. indalo sp. nov, B. yebli sp. nov., B. payoyo sp. nov. and B. tenebrosus sp. nov.), revalidate two taxa (B. maculifrons comb. nov. and B. laevigatus comb. nov.) and redefine B. majalis.

Ethnopharmacology in the Upper Guadiana River area (Castile-La Mancha, Spain)

ETHNOPHARMACOLOGICAL RELEVANCE

Determining traditional remedies for human pathologies is relevant, when compared with the standard materia medica of the pharmacopoeias and dietary supplement databases, because we can assess the species and uses that have been previously studied and target understudied species for further pharmacological investigation.

BACKGROUND

The aim of this study was to systematically record and analyze medicinal uses of natural resources (Plantae, Animalia, Fungi and minerals), mostly local, in the territories adjoining the upper Guadiana River and its tributaries. We were particularly interested in recording resources and pathologies linked to wetland areas, especially in the National Parks Las Tablas de Daimiel and Cabañeros. Wetlands are interesting because they present a double face in relation with human health: Wetlands furnish hydration, safe water, nutrition, and medicinal resources; are places from which people derive their livelihood. However wetlands are also sites of exposure to pollution or toxicants, and infectious diseases; and sites of physical hazards. We wanted to identify procedures for preparation of medicinal formulae and routes of administration. We also intended to detect whether a geographical pattern exists or not in our records in relation to the use of local resources.

METHODS

We used semi-structured interviews with one-to-one informants or groups, from 1998 to 2018. Raw data were introduced in a Firebird database and analyzed. To identify ingredients and pathologies we consulted local floras and epidemiological literature. Finally, we compared documented pathologies, remedies and ingredients in the historical context of medicinal uses of natural resources in Castile-La Mancha and especially in Ciudad Real.

RESULTS

126 pathologies and 220 species furnishing ingredients have been recorded from the interviews. In total, 188 are plants and 20 animals. The most commonly used species include Malva sylvestris, Phlomis lychnitis, Genista tridentata and Thymus mastichina. Most records refer to flowers, or fruits, of locally available plant species, classified as Mediterranean, European or widespread that belong to the Lamiaceae, Compositae or Leguminosae. Ingredients which are collected in open shrublands, known as "garrigue", and dry grasslands furnish a relevant proportion of records while the imported ingredients remain marginal. The contribution of wetlands, riverine habitats and irrigated fields and gardens as a source of medicinal resources is 36% of the records. It is relatively high considering its limited presence in terms of total extension within the study area. The most frequently reported diseases are respiratory, gastrointestinal, dermatological and infectious or parasitic.

CONCLUSIONS

Along the Guadiana River in the Ciudad Real province exists a wide and deep knowledge of traditional remedies for the treatment of common pathologies, based fundamentally on the use of local flora, fauna and mineral resources. The uses and ingredients documented are useful for further pharmacological investigation to improve health care for a wide range of pathologies.

Antiparasitic Properties of Cantharidin and the Blister Beetle Berberomeloe majalis (Coleoptera: Meloidae)

Cantharidin (CTD) is a toxic monoterpene produced by blister beetles (Fam. Meloidae) as a chemical defense against predators. Although CTD is highly poisonous to many predator species, some have evolved the ability to feed on poisonous Meloidae, or otherwise beneficially use blister beetles. Great Bustards, Otis tarda, eat CTD-containing Berberomeloe majalis blister beetles, and it has been hypothesized that beetle consumption by these birds reduces parasite load (a case of self-medication). We examined this hypothesis by testing diverse organisms against CTD and extracts of B. majalis hemolymph and bodies. Our results show that all three preparations (CTD and extracts of B. majalis) were toxic to a protozoan (Trichomonas vaginalis), a nematode (Meloidogyne javanica), two insects (Myzus persicae and Rhopalosiphum padi) and a tick (Hyalomma lusitanicum). This not only supports the anti-parasitic hypothesis for beetle consumption, but suggests potential new roles for CTD, under certain conditions.

Therapeutic arthropods and other, largely terrestrial, folk-medicinally important invertebrates: a comparative survey and review

Traditional healing methods involving hundreds of insect and other invertebrate species are reviewed. Some of the uses are based on the tenet of "similia similibus" (let likes be cured by likes), but not all non-conventional health promoting practices should be dismissed as superstition or wishful thinking, for they have stood the test of time. Two questions are addressed: how can totally different organ systems in a human possibly benefit from extracts, potions, powders, secretions, ashes, etc. of a single species and how can different target organs, e.g. bronchi, lungs, the urinary bladder, kidneys, etc. apparently respond to a range of taxonomically not even closely related species? Even though therapeutically used invertebrates are generally small, they nevertheless possess organs for specific functions, e.g. digestion, gas exchange, reproduction. They have a nervous system, endocrine glands, a heart and muscle tissue and they contain a multitude of different molecules like metabolites, enzymes, hormones, neurotransmitters, secretions, etc. that have come under increased scientific scrutiny for pharmacological properties. Bearing that in mind it seems likely that a single species prepared and used in different ways could have a multitude of uses. But how, for example, can there be remedies for breathing and other problems, involving earthworms, molluscs, termites, beetles, cockroaches, bugs, and dragonflies? Since invertebrates themselves can suffer from infections and cancers, common defence reactions are likely to have evolved in all invertebrates, which is why it would be far more surprising to find that each species had evolved its own unique disease fighting system. To obtain a more comprehensive picture, however, we still need information on folk medicinal uses of insects and other invertebrates from a wider range of regions and ethnic groups, but this task is hampered by western-based medicines becoming increasingly dominant and traditional healers being unable and sometimes even unwilling to transmit their knowledge to the younger generation. However, collecting and uncontrolled uses of therapeutic invertebrates can put undue pressure on certain highly sought after species and this is something that has to be borne in mind as well.

Folk knowledge of invertebrates in Central Europe - folk taxonomy, nomenclature, medicinal and other uses, folklore, and nature conservation

BACKGROUND

There is scarce information about European folk knowledge of wild invertebrate fauna. We have documented such folk knowledge in three regions, in Romania, Slovakia and Croatia. We provide a list of folk taxa, and discuss folk biological classification and nomenclature, salient features, uses, related proverbs and sayings, and conservation.

METHODS

We collected data among Hungarian-speaking people practising small-scale, traditional agriculture. We studied "all" invertebrate species (species groups) potentially occurring in the vicinity of the settlements. We used photos, held semi-structured interviews, and conducted picture sorting.

RESULTS

We documented 208 invertebrate folk taxa. Many species were known which have, to our knowledge, no economic significance. 36 % of the species were known to at least half of the informants. Knowledge reliability was high, although informants were sometimes prone to exaggeration. 93 % of folk taxa had their own individual names, and 90 % of the taxa were embedded in the folk taxonomy. Twenty four species were of direct use to humans (4 medicinal, 5 consumed, 11 as bait, 2 as playthings). Completely new was the discovery that the honey stomachs of black-coloured carpenter bees (Xylocopa violacea, X. valga) were consumed. 30 taxa were associated with a proverb or used for weather forecasting, or predicting harvests. Conscious ideas about conserving invertebrates only occurred with a few taxa, but informants would generally refrain from harming firebugs (Pyrrhocoris apterus), field crickets (Gryllus campestris) and most butterflies. We did not find any mythical creatures among invertebrate folk taxa. Almost every invertebrate species was regarded as basically harmful. Where possible, they were destroyed or at least regarded as worth eradicating. However, we could find no evidence to suggest any invertebrate species had suffered population loss as a result of conscious destruction. Sometimes knowledge pertaining to the taxa could have more general relevance, and be regarded as folk wisdom concerning the functioning of nature as a whole.

CONCLUSIONS

The high number of known invertebrate folk taxa suggests that it would be worth conducting further investigations in other areas of Europe.

Therapeutic and prophylactic uses of invertebrates in contemporary Spanish ethnoveterinary medicine

Zootherapeutic practices in ethnoveterinary medicine are important in many socio-cultural environments around the world, particularly in developing countries, and they have recently started to be inventoried and studied in Europe. In light of this, the purpose of this review is to describe the local knowledge and folk remedies based on the use of invertebrates and their derivative products in contemporary Spanish ethnoveterinary medicine. An overview in the fields of ethnozoology, ethnoveterinary medicine and folklore was made. Automated searches in the most important databases were performed. All related works were examined thoroughly and use-reports were obtained from 53 documentary sources. The traditional use of 18 invertebrate species and five ethnotaxa and a total of 86 empirical remedies based on the use of a single species was recorded. The two most relevant zoological groups were found to be insects and molluscs. A broad diversity of body parts or derivative products have been and are used to treat or prevent ca. 50 animal diseases or conditions, in particular diseases of the skin and subcutaneous tissue, different infectious livestock diseases, and disorders of the eye and adnexa. Cattle, sheep and equines form the group of domestic animals in which the greatest number of remedies are mentioned. In addition, seven magical remedies and practices are documented. In comparison with other culturally related areas, this is a rich heritage. The use-reports included here will help in the search for new and low-cost drugs for treating livestock and alternative materials for pharmaceutical purposes, future research addressing the validation of the effects and the development of organic farming.

Males of a strongly polygynous species consume more poisonous food than females

We present evidence of a possible case of self-medication in a lekking bird, the great bustard Otis tarda. Great bustards consumed blister beetles (Meloidae), in spite of the fact that they contain cantharidin, a highly toxic compound that is lethal in moderate doses. In addition to anthelminthic properties, cantharidin was effective against gastrointestinal bacteria that cause sexually-transmitted diseases. Although both sexes consumed blister beetles during the mating season, only males selected them among all available insects, and ingested more and larger beetles than females. The male-biased consumption suggests that males could use cantharidin to reduce their parasite load and increase their sexual attractiveness. This plausibly explains the intense cloaca display males perform to approaching females, and the meticulous inspection females conduct of the male's cloaca, a behaviour only observed in this and another similar species of the bustard family. A white, clean cloaca with no infection symptoms (e.g., diarrhoea) is an honest signal of both, resistance to cantharidin and absence of parasites, and represents a reliable indicator of the male quality to the extremely choosy females. Our results do not definitely prove, but certainly strongly suggest that cantharidin, obtained by consumption of blister beetles, acts in great bustards as an oral anti-microbial and pathogen-limiting compound, and that males ingest these poisonous insects to increase their mating success, pointing out that self-medication might have been overlooked as a sexually-selected mechanism enhancing male fitness.