Mites as Selective Fungal Carriers in Stored Grain Habitats

Abstract

Mites are well documented as vectors of micromycetes in stored products. Since their vectoring capacity is low due to their small size, they can be serious vectors only where there is selective transfer of a high load of specific fungal species. Therefore the aim of our work was to find out whether the transfer of fungi is selective. Four kinds of stored seeds (wheat, poppy, lettuce, mustard) infested by storage mites were subjected to mycological analysis. We compared the spectrum of micromycete species isolated from different species of mites (Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae, Caloglyphus rhizoglyphoides and Cheyletus malaccensis) and various kinds of stored seeds. Fungi were separately isolated from (a) the surface of mites, (b) the mites' digestive tract (= faeces), and (c) stored seeds and were then cultivated and determined. The fungal transport via mites is selective. This conclusion is supported by (i) lower numbers of isolated fungal species from mites than from seeds; (ii) lower Shannon-Weaver diversity index in the fungal communities isolated from mites than from seeds; (iii) significant effect of mites/seeds as environmental variables on fungal presence in a redundancy analysis (RDA); (iv) differences in composition of isolated fungi between mite species shown by RDA. The results of our work support the hypothesis that mite-fungal interactions are dependent on mite species. The fungi attractive to mites seem to be dispersed more than others. The selectivity of fungal transport via mites enhances their pest importance.

Ácaros em produtos armazenados comercializados em supermercados e feiras livres da cidade do Recife

“…Contudo, Matsumoto et al (1998) Hubert et al (2003) verificaram que além de o aumento da umidade relativa propiciar o desenvolvimento de ácaros, como para A. siro e T. putrescentiae, também favorece a proliferação de fungos que lhes servem de alimento.…”

In vitro and in vivo inhibition of α-amylases of stored-product mite Acarus siro

“…The mite infestation decreases food safety because mites are allergen producers (van Hage-Hamsten and Johansson 1992) and transmit mycotoxin-producing fungi (Franzolin et al 1999;Hubert et al 2003). Traditional management of stored-product mites relies on chemical acaricides on good husbandry.…”

Ultrastructure of the digestive tract in Acarus siro (Acari: Acaridida)

“…In the Czech Republic, for example, mites are the most dominant and frequent arthropod group in stored grain, infesting 65% of grain samples . Mites produce allergens and transmit mycotoxin-producing fungi (van Hage-Hamsten and Johansson, 1998;Hubert et al, 2003). Acarus siro (Acari: Acaridida: Acaridae) is the most serious mite pest in grain stores (Thind and Clarke, 2001;Stejskal et al, 2003).…”