Shevtchenkella serrata (Nalepa, 1892)

Chetverikov, Philipp E., Desnitskiy, Alexey G., Klimov, Pavel B., Ozman-Sullivan, Sebahat K., Romanovich, Anna E. & Sukhareva, Sogdiana I., 2023, Tuerkayana rotundum, Zoological Studies 62 (35), pp. 1-18 : 15-16

Association of S. serrata with maple ( A. platanoides ) generative organs: ecological and evolutionary notes

In addition to the common eriophyoid life style on leaves and hibernating near buds on twigs, the deuterogynous species S. serrata infest immature maple samaras, feed on the pericarpal epidermis until the ripe samaras fall on the ground, overwinter in the crevices of the winged pericarp, and migrate in spring to seedlings where they start feeding and reproducing ( Chetverikov et al. 2022). As a result, a new young host is infested at the very start of its life, a phenomenon known as vertical transmission in various parasitic systems ( Poulin 2011). According to Ponomareva (1978, p. 29), sympatric populations of vagrant eriophyids of two different habitus ( Shevtchenkella -like and Anthocoptes -like), possibly conspecific seasonal forms, were common on the leaves of maples at the end of summer in Kyrgyz Republic. Ponomareva (1978) also reported that one of the unnamed anthocoptine species (highly likely the deutogyne of Shevtchenkella ) was twice as numerous on samaras of Acer tataricum L. subsp. semenovii as on leaves and formed colonies (~30 mites) in micro-cavities of the pericarp. The author did not check the samaras on the ground but reported that in winter the same mites were found hibernating in the bases of buds and in bark crevices. These data suggest that association with generative organs may be common for eriophyoids on Acer spp. and may be an important aspect of their ecology.

Seeds of different maples, including A. platanoides , require cold stratification to break dormancy, but some, such as A. saccharinum , germinate immediately ( Hong and Ellis 1990; Gleiser et al. 2004). Specialists of the private arboretum “Sad lesa” situated in the village of Krasniy Partisan of the Altai Krai in Russia (sad-lesa.ru/spravka/ acer/) reported that 6 of the 14 Acer spp. tested in the arboretum germinated in the second or third year ( A. mandshuricum Maxim. , A. campestre L., A. barbinerve Maxim. , A. palmatum Thunb. , A. tegmentosum Maxim. , A. pseudosieboldianum (Pax) Kom. ) and the other eight germinated in the spring of the first year ( A. pseudoplatanus L., A. mono Maxim. ex Rupr. , A. platanoides L., A. ginnala Maxim. , A. saccharum Marshall , A. semenovii Regel & Herder , A. tataricum L., A. rubrum L.). The 14 tested maple species also differed in the proportion of successfully overwintered seeds, with the minimum values for seed germination about 50% in A. saccharum and A. rubrum . Apparently the host plant species with a single season dormancy period and a high germination rate are the most likely to support the development of overwintering associations of eriophyoids with seeds in regions with a cold climate. Besides maples, various deciduous broadleaf trees of the genera, Fraxinus , Tilia and Ulmus , possess samaras, and taxa with rapidly germinating seeds could have similar “mite-samara” associations to that we observed on A. platanoides .

In S. serrata , the hibernation of deutogynes on seeds fallen on the ground is an additional diapause mode because typically eriophyoids on this host overwinter on the young twigs. Interestingly, hibernation on seeds implies a long period of survival in leaf litter on the soil and spring migration from the germinating samara to the developing seedling. Data from literature suggest that many eriophyoid species have a period in their life cycle when they are closely associated with soil or even live on the plant parts at the soil level. Although eriophyoids have not been reported as feeding on roots, they have been found feeding and overwintering on below-ground buds of stems and leaves on a rhizomatous perennial, or on modified leaves such as bulb scales ( Krantz and Ehrensing 1990; Petanović et al. 1997; Asadi et al. 2014; Chetverikov et al. 2021b). These reports may indicate an underestimated role of the soil in the ecology of eriophyoid mites. Association with soil in extant eriophyoids could be some kind of an ecological throwback to when nematalycid-like ancestors of the eriophyoids started developing associations with the above-ground organs of plants ( Bolton et al. 2017 2018; Klimov et al. 2018 2022). A search for eriophyoids in soil and leaf litter samples and careful investigations of the invertebrates associated with plant roots and mycorrhizae, especially in ancient intact biomes like the forests of Amazonia, Kalimantan and Australia, may result in the finding of unusual forms of eriophyoids or eriophyoid-like mites that could help clarify the evolutionary relationship between the ancestral soil mites and contemporary phytophagous eriophyoids.