Gregory Thomas Sullivan

The megadiverse invertebrates are a fundamental component of global ecological functioning. There are estimated to be millions of unnamed species of terrestrial and aquatic arthropods alone. Limited expertise and funding mean that taxonomists across the world are only able to name a minute proportion of the undescribed species every year. One of the outstanding contributors is Dr. Mark Stephen Harvey, an Australian arachnid specialist, whose ‘obsession’ with that group began nearly 50 years ago. In 2025, he alone and with colleagues published 137 new species and 17 new genera. In the same year, Dr. Harvey joined the exclusive group of taxonomists who have described 1,000 species; most of his extraordinary total are pseudoscorpions and spiders, but also includes millipedes, scorpions, water mites and velvet worms. The efforts of Dr. Harvey and other taxonomists in cataloguing global biodiversity are vital to the study of disciplines such as ecology, evolution, biogeography, genetics and speciation; public education; and the promotion and implementation of biodiversity conservation across the planet.

Aim: This paper is a response to Li and Xue (2024) regarding the global species richness and distribution of the eriophyoid mites, which are highly host‐specific phytophages.Discussion: The number of described plant species is approaching 400,000. This enormous level of plant diversity has played a fundamental role in the diversification of the eriophyoids. Ozman‐Sullivan and Sullivan (2023) estimated there are at least 250,000 eriophyoid species, with most species highly likely to be in the largely neglected subtropical and tropical regions. Li and Xue (2024) argued that there could be far less than 250,000 eriophyoid species. We assert that this high number is realistic and possibly conservative. As an example, Ozman‐Sullivan and Sullivan (2023) reported that just 11 well‐studied plant species collectively host ~200 eriophyoid species. Habitat destruction and climate change represent increasingly dire threats to the existence of thousands of plant species and their dependent eriophyoid species across the world.Location: Global.Taxon: Eriophyoid mites (Acari: Eriophyoidea).Conclusions: We present more evidence to support our estimate of at least 250,000 eriophyoid species, including a substantial tropical majority. We also elaborate on potential research on this subject. The conservation of the invertebrates, including the likely enormous number of undescribed species, is critical to the maintenance of global ecological functioning.

Continuing population declines and extinctions across the earth’s biodiversity spectrum further undermine global ecological functioning and the security of human society. A comprehensive summary of the soon to be released Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Nexus Assessment report was published in December 2024. It stated that the current environmental, social and economic crises, reflected in mounting biodiversity loss, global climate change, growing water and food insecurity and risks to human health, are inseparable. It also warned that biodiversity levels have fallen between 2% and 6% per decade for the last 30 to 50 years. The level of harm being inflicted on nature is chilling for human society given that the report also stated that ~$58 trillion of global economic activity in 2023 was in sectors moderately to highly nature dependent. Setting aside the strong moral arguments for biodiversity conservation, this situation points to a mounting economic disaster. On a positive note, the report summary did list a suite of proposals for slowing this alarming level of biodiversity loss. However, separate from the IPBES Nexus report, factors that need to be addressed include the expectation of continuous economic growth, extreme concentration of global wealth and power; economic materialism; corporate tax avoidance; public and private sector corruption; the non-incorporation of environmental costs in generating Gross Domestic Product; and the flooding of the internet with misinformation, including climate change denial.

Animal dung is an ephemeral, nutrient-rich resource that supports constantly changing, highly biodiverse invertebrate communities. The dung of large herbivores is especially attractive to invertebrates. Seven oribatid mite species in seven different families were collected from water buffalo dung from the Kizilirmak Delta on the Black Sea coast of Samsun Province in northern Türkiye. One new species, Plakoribates cernekensis n. sp. (Tegoribatidae) is described and illustrated. Bipassalozetes (B.) intermedius (Mihelčič, 1954) (Passalozetidae), Oribatella (Sacculoribatella) nasuorum Fujikawa, 2012 (Oribatellidae) and Humerobates rostrolamellatus Grandjean, 1936 (Humerobatidae) are new records for Türkiye. Peloptulus montanus Hull, 1914 (Phenopelopidae), Oribatula (O.) interrupta (Willmann, 1939) (Oribatulidae) and Scheloribates (S.) pallidulus (Koch, 1841) (Scheloribatidae) were also collected. Further taxonomic investigation of the richly biodiverse Kizilirmak Delta wetlands would likely reveal many new invertebrate species.

The highly variable ’leafscapes’ of plants across the world represent billions of square metres of mite habitat. The phytoseiid mites (Acari: Phytoseiidae), an extremely species-rich group of mostly generalist predators, are providers of ecosystem services for humanity worth many hundreds of millions of dollars annually by helping suppress phytophagous mites and insects in forests, agro-ecosystems, shade-houses and home gardens. In this study, the phytoseiid mite assemblages on the leaves of four species of common tree species, namely oak (Quercus cerris var. cerris), poplar (Populus deltoides, P. nigra) and walnut (Juglans regia), were compared. The three data sets used were generated in three independent seasonal studies in Samsun Province, Türkiye, between 2018 and 2022. In total, mite species in 18 families, including 15 families on walnut, were recorded. Nineteen phytoseiid species in 13 genera, Amblydromalus, Amblyseius, Euseius, Kampimodromus, Neoseiulella, Neoseiulus, Paraseiulus, Phytoseius, Transeius, Typhlodromina, Typhlodromips, Typhlodromus and Typhloseiulus, were collected. Only Eusieus amissibilis was collected from all three tree genera, whereas 14 species were collected from only one tree genus. Shannon diversity and Jaccard similarity indexes were calculated for mite families and phytoseiid genera and species. Potential reasons for the observed differences in the phytoseiid assemblages on the different host trees are explored in depth. In the ‘big picture’, global biodiversity, likely including many undescribed phytoseiid species, is threatened by widespread habitat degradation and destruction, especially in the tropics, and accelerating climate change, and rapidly stopping them is imperative.

Kampimodromus corylosus Kolodochka (Acari: Phytoseiidae), which is reported for the first time from Türkiye, is re-described and illustrated, based on female specimens collected from hazelnut (Corylus avellana L., Betulaceae). In addition, the reinstatement of K. adrianae Ferragut and Peña-Estévez as a valid species is proposed. A revised identification key for the world’s Kampimodromus Nesbitt species is also provided.

Aim: The global distribution and diversity of mites, including the species rich and highly host plant‐specific eriophyoid mites, are important questions in biogeography and biodiversity conservation. Here we critique the paper of Li et al. (2023) titled ‘Global patterns and drivers of herbivorous eriophyoid mite species diversity’.Location: GlobalTaxon: Eriophyoid mites (Acari: Eriophyoidea)Methods: We assert that the data set utilized (less than 4,500 eriophyoid species) consisted of only the described extant species, not all extant species. We then provide evidence that the utilised data set represents only a small proportion of the likely global total of eriophyoid species and therefore provides a far from complete representation of their global distribution.Results: Most collections of extant eriophyoid mites have been conducted in temperate regions where most taxonomic specialists have been active, and not in the largely unstudied tropical regions which contain a very substantial majority of all plant diversity. Most undescribed eriophyoid diversity is therefore highly likely to be found in the tropics. This suggests that the global modelling analyses of Li et al. (2023) were very likely applied to a highly inaccurate data set.Main Conclusions: The actual global distribution and total number of eriophyoid mite species can only be more reliably estimated by systematic taxonomic studies that cover the entire global distribution of plant diversity, which implies a strong focus on the tropical regions.

Invasions by alien plant species are rapidly increasing in both their extent and intensity, leading to the widespread degradation of terrestrial and aquatic ecosystems across the world. One of the most widely dispersed, invasive, alien plant species in Europe, North America and many other countries, including Türkiye, is the tree of heaven, Ailanthus altissima. Numerous potential biological control agents, including eriophyoid mites, have been reported from this plant within its native range. A widespread collection of leaf specimens from the tree of heaven in Türkiye yielded only the eriophyoid, Aculus taihangensis (=A. mosoniensis), a new record for Türkiye. No obvious damage was observed on any of the leaf specimens. It appears highly unlikely that A. taihangensis is currently playing a meaningful role in the biological control of the tree of heaven in Türkiye.

Coextinction is a major and growing threat to global biodiversity. One of the affected groups is the eriophyoid mites (Prostigmata: Eriophyoidea) which are highly host plant specific. They have been described from an enormous range of annual and perennial plants from grasses to giant forest trees. It is highly likely that there are huge numbers of undescribed eriophyoid species in the subtropical and tropical regions which harbor an extraordinary wealth of plant diversity. The global total of eriophyoid species is estimated to be at least 250,000 but it could be much higher. However, the continuing destruction and degradation of natural habitat, especially tropical forests, and climate change, together pose extreme, on-going threats to the eriophyoid mites because of their vulnerability to co-extinction with their host plants. It has been reported that one third of all the Earth’s plant species are now at risk of extinction. Together with enormous numbers of other invertebrate species, it is highly likely that many thousands of eriophyoid species are disappearing in the current mass extinction event. Population decline and co-extinction, especially of the invertebrates, are greatly accelerating total biodiversity losses. The termination of habitat destruction and degradation; establishment of large, representative protected areas; restoration of degraded areas; and rapid reduction of fossil fuel use, are urgent tasks. However, the long term conservation of biodiversity can only be achieved through comprehensive social, economic and political reforms across the world that prioritize environmental protection, peaceful coexistence, social justice and the sustainable use of resources.

Since the 1970’s, biodiversity, conservation and ecology journals have published increasing numbers of reports of major, widespread losses of the diversity and abundance of plants, vertebrates and invertebrates, mostly insects, especially in tropical regions. Mites make a major contribution to global ecosystem services and ecological functioning. Reports on diversity and abundance losses among mites, including ticks, have appeared more recently. The huge problems of population decline and direct extinction among free-living invertebrate species across the world are compounded by the host dependency of enormous numbers of other invertebrate species, which puts them at serious risk of secondary endangerment and co-extinction. They include huge numbers of mite species in symbiotic relationships, including phoretic and parasitic relationships, and the highly host-specific, phytophagous eriophyoids. The destruction and degradation of terrestrial and aquatic ecosystems and habitats across the world, especially for agricultural expansion and intensification, are the major causes of biodiversity loss, with climate change, pollution, overexploitation, invasive species and pesticide use among other contributors. Measures and activities that would substantially contribute to saving the great majority of the world’s remaining biodiversity include the protection of all remaining areas of natural and semi-natural habitat, especially the subtropical and tropical forests, with the 36 global biodiversity hotspots an absolute priority; habitat restoration with local species; higher global soil carbon levels; rapid transition from fossil fuel use to renewable energy sources to stop climate change; minimization of pollution; universal education and social justice; a lower human population; and sustainable use of global resources. The rapid implementation of these and other practical measures at the local, national and global scales is essential to ensure the long term survival of the vast majority of biodiversity, including mite species.