Title: Competition among species of stored-product psocids (Psocoptera) in stored grain Authors
Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 22, 2014
Publication Date: August 8, 2014
Citation: Athanassiou, C.G., Kavallieratos, N.G., Throne, J.E., Nakas, C.T. 2014. Competition among species of stored-product psocids (Psocoptera) in stored grain. PLoS One. 9(8):e102867 (11pgs). DOI: http://dx.doi.org/10.1371/journalpone.0102867. Interpretive Summary: Psocids are pests of stored grain and processed grain products, but we know little about their ecology and how this impacts their pest status. We evaluated the competition among stored-product psocid species in laboratory experiments to help explain their distribution in the field and their pest status. When reared at 30°C with equal starting population numbers, Liposcelis bostrychophila was the dominant species, and its presence had a negative effect on the population growth of L. decolor and L. paeta. In a second series of tests, Liposcelis bostrychophila was the dominant species, regardless of the ratio of parental females in the starting mixed populations (L. bostrychophila adults:Lepinotus reticulatus adults 10:0, 9:1, 7:3, 5:5, 3:7, 1:9 and 0:10). In mixed populations, L. reticulatus was present after 175 days only in vials that contained this species alone. Our results help to explain why L. bostrychophila is one of the most common pests of stored products because they outcompeted other psocid species in this series of experiments.
Technical Abstract: We evaluated the competition of stored-product psocid species, by conducting two series of laboratory experiments. In the first series, three Liposcelididae were used: Liposcelis bostrychophila, L. decolor and L. paeta. Five adult females of these species were placed in vials, either alone or in all possible combinations of two species. The number of adults in the vials was counted after 35, 70, 105, 140, and 175 d. These tests were performed at two temperature levels, 25 and 30°C. At 25°C, there were no differences in L. bostrychophila numbers when this species was either alone or with each of the other two species. At 30°C, L. bostrychophila was the dominant species, while its presence had a negative effect on the population growth of L. decolor and L. paeta. In the second series of tests, L. bostrychophila adults were placed either alone or with adults of Lepinotus reticulatus (Trogiidae), at the ratios of (L. bostrychophila adults: L. reticulatus adults) 10:0, 9:1, 7:3, 5:5, 3:7, 1:9 and 0:10. These tests were carried out only at 30°C, while the observation periods were the same as above. Liposcelis bostrychophila was the dominant species in this case as well, regardless of the ratio of the parental females. In contrast, L. reticulatus at the end of the experimental period was present only in vials that contained this species alone. Our results suggest that L. bostrychophila can be the winner in the competition with other stored product psocid species, but the outcome of this competition is highly affected by temperature, species and observation period.