Life history and population growth parameters of the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae) fed on 10 rice cultivars and lines

Abstract

The rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), is one of the most destructive pests of stored cereal grains globally. In this study, we evaluated the grain resistance of different rice cultivars (Anam, Gilar, Hashemi, Keshvari, Rash, and Tisa) and lines (8608, MN-7, TH-1, and TH-2) using life history and life table parameters of S. oryzae under laboratory conditions (28 ± 1°C, 70 ± 5% relative humidity, and complete darkness). The immature survival of S. oryzae decreased significantly when it was reared on Rash. Among tested grains, developmental time was the longest on Rash and the shortest on Hashemi. Compared with the other cultivars and lines, the fecundity (number of eggs laid) was significantly lowest on Rash. The highest intrinsic rate of increase (rm) was recorded in S. oryzae reared on Hashemi and the lowest was on Rash. The grain weight loss (%) was the highest when S. oryzae was fed on Anam and TH-1, and lowest when it was reared on Rash. Significant negative correlations were recorded between the starch, protein and total phenolics content of tested grains and fecundity, rm, net reproductive rate (R0), and finite rate of increase (λ) of S. oryzae. The present research revealed that Rash cultivar was more unsuitable to S. oryzae than the other cultivars and lines because of slow developmental time, poor fecundity, low grain weight loss and low rm value on this cultivar. Our results could help to select resistant rice cultivars to S. oryzae for production of transgenic grains.

Effect of different chemical properties of cereal grains on the foraging and microbiome of the rice weevil (<i>Sitophilus oryzae</i> L.)

“…According to Majd-Marani et al (2023), the content of phenols and lipids in the food eaten by insects may also significantly impact development. Significant relationships between the development time, longevity, and fecundity of S. oryzae and the content of phenols in the tested grains reveal this factor's important role in the rice weevil's life cycle.…”

“…Based on the results of previous scientific studies, it appears that the impact of the content of fatty acids in grains on the development of insects, available information suggests that the fat content in most cereal plants plays an important role in shaping the storage stability of cereal products and may influence the feeding behaviour of S. granarius (Liu, 2011). The research of Majd-Marani et al (2023) correlation analysis showed that the content of glycogen and lipids in S. oryzae pupae has significant relationships with development time, fecundity, and longevity of adults. In research conducted by Nietupski et al (2021), no significant relationships were revealed between the level of individual fatty acids in grains of various wheat varieties and parameters related to the development of the grain weevil.…”