Leaf domatia and protection of a predatory mite Typhlodromus doreenae Schicha (Acari: Phytoseiidae) from drying humidity

Abstract

When plant characteristics influence interactions between herbivores and their natural enemies, mutualism can result between plants and the third trophic level. Leaf domatia, small hair tufts, pockets, or pits in the leaf surface, frequently shelter predaceous and fungivorous mites that may decrease the impact of plant herbivores and fungal pathogens. Benefits that accrue to sheltered mites are unclear. One hypothesis is that domatia protect mites from drying humidity they would otherwise experience on the leaf surface. This hypothesis was tested using laboratory microcosms with leaves of two plant species, Viburnum tinus (Caprifoliaceae) and Coprosma repens (Rubiaceae), and a native Australian phytoseiid mite, Typhlodromus doreenae. Domatia were either removed or retained on leaves and the distribution and performance of T. doreenae provided with pollen as a food source was assessed at four levels of relative humidity (30%, 50%, 70% and 98% RH). When domatia were available, most adults and offspring of T. doreenae were found there, irrespective of RH level or plant species. The presence of domatia increased retention of adult mites on leaves of C. repens but not V. tinus. Domatia of both plant species increased mite reproduction but only at RH >70% on C. repens and at 98% on V. tinus. These results indicate that T. doreenae benefits from domatia, but these benefits are not strongly related to drying humidity. Other hypotheses, including escape from predators, may better explain association of mites with leaf domatia. Irrespective of RH, this predatory mite did benefit from use of domatia for shelter and reproduction, supporting a key requirement for plant-mite mutualism.

Contradictions in host plant resistance to pests: spider mite (Tetranychus urticae Koch) behaviour undermines the potential resistance of smooth‐leaved cotton (Gossypium hirsutum L.)

“…Such a difference could possibly be due to the provision of a more suitable microenvironment for feeding and oviposition 12. Research with leaf domatia found no evidence that their presence on leaves helped protect predatory mites from drying humidity 21. However, herbivorous mites, which must spread across the leaf surface for colonies to expand and feed, are constantly exposed to ambient conditions, which may be extreme.…”

“…Leaves with domatia, or ‘little houses’, often have more predatory mites than leaves without 20. The exact reasons for this are unclear, and apparently not related to protection from low humidity,21 although in those experiments mites were not exposed to the combination of high temperatures, low ambient relative humidity and windy conditions common in the field. Leaf hairiness can also have positive or negative effects on abundance of herbivorous arthropods.…”

Influence of environment on the leaf morpho-anatomy and histochemical of the ayahuasca leaf: Populations cultivated in extra-Amazonian regions

“…However, this structure has been identified in several Psychotria species of the Atlantic Forest and it has been considered as an important taxonomic characteristic for genus determination (Moraes et al, 2011). These are key to the leaf system because they are microstructures closely related to the control of fungal pathogens and to several recognition of taxa (Oliveira, Rebouças, Leite, Oliveira, & Funch, 2018;Rowles & O'Dowd, 2009). Thus, studies in other biomes are still necessary to determine important anatomical and morphological characters for correct diagnosis within Psychotria.…”

In search of artificial domatia for predatory mites

“…RH absorbency capacity of artificial domatia had no impact on oviposition inside, which may be explained by the high level of RH maintained in the laboratory experiment. In addition, other studies have reported contrasting results regarding the microclimate benefits of domatia on mite populations (Ferreira et al, 2010;Grostal & O'Dowd, 1994;Norton et al, 2001;Rowles & O'Dowd, 2009;Walter, 1996).…”