A common phytoseiid in cucurbit systems shows patterns of diverse non-prey resource consumption in fields in the Southeast U.S.

Proprioseiopsis mexicanus (Acari: Phytoseiidae), a common predatory mite in many cucurbit agroecosystems across the eastern U.S., is the most frequently collected predator in watermelon fields in South Carolina, USA, but up until recently, its ecology and trophic range have been unknown. We reared P. mexicanus to investigate the questions 1) what is the range of common prey and non-prey resources utilized for survival and reproduction in laboratory experiments? 2) how do these resources compare in developmental time, pre-oviposition time, and number of eggs produced? and 3) what is the molecular evidence for non-prey resources being consumed in fields? Cucurbit and common pollens in cucurbit fields experimental resources tested in the laboratory. All pollen resources were able to be consumed but C. lanatus, D. cooperi, and T. incarnatum pollens resulted in the shortest time to development, shortest pre-oviposition time, and most eggs laid/day. We also observed that in the limited number of pollen resources studied that the smaller pollens (< 20 µm) showed a trend toward being better quality than larger ( >80 µm) pollens. Gut-content analysis of P. mexicanus females from watermelon fields on the Clemson University CREC experimental farm and on the property of a grower revealed interesting spatial patterns of consumption including more diverse consumption inside versus outside a field. Pattern details and possible implications for biocontrol are discussed.