The effect of some abiotic factors on morphometrical parameters of the female stage of the Rhizoglyphus robini (Astigmata: Acaridae) in the saffron field.

Saffron (Crocus sativus: Iridaceae) is a fall-blooming perennial plant and its dried stigma is the priciest spice and a key non-oil export for Iran's economy. The bulb mite, Rhizoglyphus robini, is a polyandrous and multivoltine species and its damage to saffron corms directly and indirectly causes lower yields of saffron crops. Environmental conditions and abiotic factors, such as temperature, humidity, density, and diet affect the morphological traits of living organisms and subsequently affect biological abilities. In this study, changes in temperature, soil moisture, density (nymphs + adults), time, and corm weight on the morphological traits of the saffron bulb mite, including body length and width, and leg sizes of adult females were investigated in a saffron field in the Dargaz County of Iran during 2022. The results of variance analysis of the morphometrical parameters of the mite species, including body length, body width, and four pairs of legs in different months were significant. Based on simple and multiple linear regression models as well as non-linear regression, the effect of temperature and density (nymphs + adults) was reversed and the effect of soil moisture and corm weight was direct on morphometrical parameters of this species. Based on our results, soil moisture has a strong relation with female body size traits (body length, width, and leg lengths). This indicates that irrigation cycle management might be an important factor in bulb mite management in saffron agroecosystems. [ABSTRACT FROM AUTHOR]