Morphological Ontogeny and Ecology of a Common Peatland Mite, Nanhermannia coronata (Acari, Oribatida, Nanhermanniidae)

Abstract

Nanhermannia coronata Berlese, 1913, is a common and abundant oribatid species in peatlands but can be easily mistaken for N. sellnicki Forsslund, 1958, as an adult. Therefore, the identity of adults of N. coronata from several sites in Norway and Ireland was supported by the COI sequence data, and based on this material, the morphological ontogeny of this species is described and illustrated to highlight the differences between N. coronata and N. sellnicki. In all juvenile stages of N. coronata, the bothridial seta is absent, but two pairs of exobothridial setae are present, including short exp and exa reduced to its alveolus. In the larva, seta f1 is setiform, but in the nymphs, it is reduced to its alveolus. Most prodorsal and gastronotal setae of larva are short, and of nymphs they are long. In all instars, the leg segments are oval in cross section and relatively thick, and many setae on tarsi are relatively short, thick and conical, except for longer apical setae. Seta d accompanies solenidion σ on all genua, φ1 on tibia I and φ on other tibiae. We found some morphological characters that clearly differentiate N. coronata from N. sellnicki, like the number of setae on femora of adults and tritonymphs, the shape of insertions of prodorsal seta in and all gastronotal and adanal setae of juveniles; in N. sellnicki, these setae are inserted in small individual depressions, whereas in N. coronata, these depressions are absent. Our ecological observations confirm a common occurrence of N. coronata in raised bogs, a high percentage of juvenile stages in its populations and a preference of this species for humid microhabitats, whereas N. sellnicki is less common than N. coronata and occurs in drier habitats.

Vertical Distribution of Mites (Acari) in a “Miniature Forest” of Sphagnum Mosses in a Forest Bog in Western Norway

“…Nanhermannia coronata was the most abundant species in this study and occurred in all Sphagnum layers, confirming the results from other studies [1,20]. This species occurs abundantly in bogs and has wide preferences for bog microhabitats, e.g., hummocks, lawns, and hollows [42]. In two bogs in Trøndelag (Norway), the adults dominated in the age structure at the end of June (making up on average 65% of populations of this species), larvae made up 4%, protonymphs 10%, deutonymphs 12%, and tritonymphs 10%.…”

“…This was because of the abundant occurrence of Nanhermannia coronata in this layer. The species has a body length of 480-570 µm; however, it has a narrow, cylindrical body, with a mere width of 228-260 µm [42], so it can easily migrate to deeper layers of Sphagnum bogs. Nanhermannia coronata belongs to secondary decomposers, i.e., predominantly feeding on fungi, and partly on litter [80], so it can use different food resources at different depths.…”

“…The mite groups (Oribatida, Mesostigmata, and Prostigmata) were counted under a stereomicroscope, including both adults and juveniles. The Oribatida were further determined to species or genus level using the key for adults [32] and other publications to identify the juvenile instars [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. Nomenclature follows Subías [51,52] and partly Weigmann [32].…”

Morphological Ontogeny, Ecology, and Biogeography of Fuscozetes fuscipes (Acari, Oribatida, Ceratozetidae)

“…A similar pattern of haplotype identity was found for Platynothrus peltifer (C.L. Koch, 1839) in Western Norway, Belgium, and Germany [102]; P. punctatus (L. Koch, 1879) in Svalbard, Western Norway, and Southern Spain [103]; and Nanhermannia coronata Berlese, 1913, in Northern, Central, and Southern Norway, Ireland, and Finland [104]. We may hypothesize that their migration in a latitudinal direction is largely influenced by migrating birds.…”

The Ecology, Evolution, Systematics, and Behaviour of Mites

“…The incorporation of molecular techniques into mite research [14][15][16][17][18][19] has revolutionized our understanding of mite evolution, genetic diversity, and phylogenetic relationships. Studies on the biogeography of Fuscozetes fuscipes [14], genetic diversity in quill mites [15], and the ontogeny and ecology of Nanhermannia coronata [16] have demonstrated the utility of DNA barcoding and molecular phylogenetics in uncovering hidden diversity and clarifying taxonomic relationships. Molecular identification of Laelapidae mites [17] and description of a new Ultratenuipalpus species [18] further illustrate the power of molecular data in advancing our understanding of mite biology.…”