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Journal : Cropsaver : Journal of Plant Protection

Sub-lethal Competition of Joint Predators (Pardosa pseudoannulata and Menochilus sexmaculatus) when Predating Nilaparvata lugens at Different Densities Siregar, Riza Wardani; Syahrawati, My; Arneti, Arneti; Hamid, Hasmiandy
CROPSAVER Vol 6, No 1 (2023)
Publisher : Departemen Hama dan Penyakit Tumbuhan Fakultas Pertanian Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/cropsaver.v6i1.42864

Abstract

Pardosa pseudoannulata and Menochilus sexmaculatus are two predators of the brown planthopper (BPH, Nilaparvata lugens, Hemiptera: Delphacidae) in rice fields. The research aimed to determine the predation and the competition model of P. pseudoannulata and M. sexmaculatus on different BPH densities. This study used a completely randomized design (CRD) factorially. The first factor was the difference in predator species (P. pseudoannulata, M. sexmaculatus, and a combination of predators P. pseudoannulata + M. sexmaculatus), and the second was the difference in N. lugens density (0, 30, 50, and 70 individuals). The treatment was repeated in 4 repetitions. The parameters observed were predatory and competitive behavior, predation rate, body weight gain, and competition model. The research showed that P.pseudoannulata was more aggressive in finding and catching prey than M. sexmaculatus. The more prey provided, the higher the predation rate of the two predators. The combination of them as joint predators has increased the pressure on BPH and the predation rate, although it was still below its potential. Sub-lethal competition occurred between the two predators; it did not affect P.pseudoannulata but affected the behavior and reduced body weight of M. sexmaculatus. The competition between the two predators was not influenced by BPH density but by the intensity of meeting time. Both as joint predators in rice fields are safe and beneficial for BPH control.
Does competition between Pardosa pseudoannulata and Menochilus sexmaculatus reduce the predation rate on brown planthopper? Septriani, Utari; Syahrawati, My; Arneti, Arneti
CROPSAVER Vol 6, No 2 (2023)
Publisher : Departemen Hama dan Penyakit Tumbuhan Fakultas Pertanian Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/cropsaver.v6i2.51131

Abstract

Pardosa pseudoannulata and Menochilus sexmaculatus are classified as natural enemies of the brown planthopper or BPH (Nilaparvata lugens). This study aimed to determine the effect of differences in density on mortality and their predation rate in suppressing the BPH population. This study used a completely randomized design of 15 treatments and 3 replications. The treatments consisted of different densities of two predators (1, 2, and 3 individuals). The variables observed were predator mortality, predation rate, competition between predators, and competition behavior. The results showed that competition between predators at different densities was not directly related to predator mortality and the predation rate of joint predators. Predator density tended to increase the predation rate, especially on M. sexmaculatus (R=0.894), while the density of P. pseudoannulata and joint predators was moderate (Rpardosa=0.587, Rjoint=0.522). M. sexmaculatus won the competition when its population increased. Equal competition occurred in the composition of 1 P. pseudoannulata and 3 M. sexmaculatus (P1M3); in this composition, no deaths were found due to competition, with the predation rate reaching 86.7%. Cannibalism dominates intraspecific competition between individuals of P. pseudoannulata, while interspecific competition occurs between the two species, causing sub-lethal effects.