Dear Colleagues,

Insects (Insecta, Arthropoda) are undoubtedly the most evolutionarily successful group of organisms. The origin of insects dates back to 400-500 mya, and many insect groups have been preserved in a very similar form to the present day. With over 1.3 million described species, they account for more than ¾ of all known species on Earth, and it is estimated that at least 4-5 million insect species still remain undiscovered and undescribed. Insects are adapted to a wide variety of habitats, biotopes, and living conditions. They occupy all ecological niches except marine habitats and account for the largest part of the world's biodiversity.

People's interest in insects dates far into human history. Many insect groups and species are recognized for their medical, agricultural, or economic importance, whether beneficial or as pests, parasites, and vectors of pathogens that globally impact human communities. The focus of scientific research has therefore traditionally been on numerous insect groups, requiring accurate and reliable identification of taxa. At the same time, in a large number of insect and arthropod groups, morphological identification is extremely difficult due to the lack of reliable diagnostic characters or the existence of cryptic species and species complexes. Furthermore, as the number of trained professional taxonomists, particularly those specialized in less-studied insect groups, is declining, alternative methods of species identification are required.

In the last two decades, DNA barcoding, a rapid and reliable method for species identification, has given new impetus to taxonomic research. The establishment of a public BOLD database allows the scientific community to access public data and provides a starting point for a number of additional studies. Currently, nearly ¾ of all public records in the BOLD database are related to insects and their arthropod relatives, representing ~250,000 species in ~500,000 BINs. Entomology as a science has therefore also benefited greatly from the advent of the DNA barcoding method. Applied in the numerous studies of insects (and arthropods in general), this approach has often revealed new and hitherto undiscovered or cryptic species and flagged the existence of species complexes and evolutionarily important units, thus laying the foundation for further comprehensive integrative taxonomic research. Through DNA barcoding, the monitoring of invasive species, vectors, and economically important arthropod species is greatly facilitated, as well as monitoring the status of populations of endangered and endemic species and research on the biodiversity of specific geographic areas. In addition, DNA metabarcoding of various environmental samples is increasingly being used in ecological and surveillance projects, allowing rapid biodiversity assessment of otherwise unattainable arthropod biosystems and communities.

This Special Issue welcomes all contributions describing the advantages and application of the method of DNA barcoding and metabarcoding in most various aspects of entomological research. Descriptions of new species based on DNA barcoding will only be considered within the broader integrative taxonomic framework. In light of the current rapid loss of biodiversity, contributions that have an impact on the broadening of our knowledge of insect species richness and that aim at establishing further biodiversity screening and conservation projects, especially in understudied geographic areas, will be highly appreciated.

Dr. Branka Bruvo Mađarić
Dr. Martina Podnar Lešić
Guest Editors

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• Insecta
• Arthropoda
• DNA barcoding
• eDNA metabarcoding
• cryptic diversity
• species complex
• biodiversity conservation
• monitoring
• integrative taxonomy