Impact of intraguild predation on the biological control of Panonychus citri (McGregor) (Acari: Tetranychidae) by Phytoseiid Mites

Background: Predatory mites are essential for integrated pest management, particularly in citrus agroecosystems where Panonychus citri (citrus red mite) is a significant pest. Understanding the reproductive behavior, consumption rates, and intraguild predation (IGP) patterns of predatory mites is vital for determining their potential as biological control agents. This study evaluates three predatory mite species— Neoseiulus californicus , Neoseiulus barkeri , and Scapulaseius newsami —to better understand their reproductive and predatory behaviors under different prey combinations. Main Results: The study revealed several key patterns in the reproductive and consumption behaviors of the three predatory mite species, with notable differences in their responses to P. citri and intraguild prey. Neoseiulus californicus exhibited a preoviposition period of 1.9 days when fed P. citri and laid a total of 27.8 eggs per female with a daily egg production of 1.8. It showed a higher fecundity when compared to N. barkeri (1.25 eggs per day) and S. newsami (1.34 eggs per day). The preoviposition period for N. barkeri and S. newsami was similar, approximately 1.6-1.8 days, but N. barkeri demonstrated slightly lower reproductive rates when feeding on P. citri , with a total of 25.2 eggs and a daily egg production of 1.26 eggs. S. newsami laid 25.65 eggs and had a slightly higher daily egg production rate of 1.33 eggs. For all three species, the longevity ranged between 26 and 28 days, with no significant differences observed between species or prey conditions. N. californicus had the highest total consumption of P. citri at 412.6 individuals, with a daily consumption rate of 13.0 per female. In contrast, N. barkeri consumed 405.81 P. citri individuals, and S. newsami consumed 408.47 P. citri individuals. When both P. citri and intraguild prey ( N. barkeri or S. newsami larvae) were offered, the consumption of P. citri decreased significantly. N. californicus showed a preference for P. citri in these mixed prey conditions, with a total consumption of 150.7 P. citri individuals and a daily consumption of 3.8. N. barkeri and S. newsami showed similar patterns with lower consumption rates in mixed prey conditions. N. californicus and N. barkeri exhibited a clear preference for intraguild prey, consuming 206.86 and 206.68 phytoseiid larvae, respectively. S. newsami preferred N. californicus over N. barkeri in intraguild predation, consuming 203.48 and 186.71 phytoseiid larvae, respectively. In mixed prey conditions, N. californicus showed the highest consumption of P. citri and N. barkeri , whereas S. newsami preferred N. californicus to N. barkeri larvae, consuming significantly more of N. californicus . The presence of intraguild prey significantly reduced the total consumption of P. citri by all three species. Specifically, N. barkeri and S. newsami reduced their total P. citri consumption when mixed with their intraguild counterparts ( N. californicus and S. newsami larvae). The results were statistically significant (P < 0.05) in most cases for differences in preoviposition periods, longevity, egg production, and consumption rates. The highest variation was observed in the total consumption rates of P. citri and phytoseiid larvae when prey combinations were altered. The study analyzed the reproductive and consumption behaviors of three predatory mite species, Neoseiulus californicus , N. barkeri , and S. newsami . Neoseiulus californicus had a preoviposition period of 1.9 days and laid 27.8 eggs per female, with a daily egg production of 1.8. It had higher fecundity compared to N. barkeri and S. newsami . N. barkeri and S. newsami had similar preoviposition periods, but N. barkeri had slightly lower reproductive rates. All three species had longevity ranging between 26 and 28 days. N. californicus had the highest total consumption of P. citri at 412.6 individuals, with a daily consumption rate of 13.0 per female. When both P. citri and intraguild prey were offered, the consumption of P. citri decreased significantly. N. californicus and N. barkeri showed a preference for P. citri in mixed prey conditions, while S. newsami preferred N. californicus over N. barkeri larvae. The presence of intraguild prey significantly reduced the total consumption of P. citri by all three species. The results were statistically significant in most cases. Conclusion: This study demonstrates that Neoseiulus californicus , Neoseiulus barkeri , and Scapulaseius newsami exhibit distinct reproductive and consumption behaviors when feeding on P. citri and intraguild prey. While N. californicus showed the highest fecundity and consumption of P. citri , all three species showed preference for intraguild prey when both prey types were available. These findings emphasize the complex interactions of predatory mites in biological control, suggesting that their effectiveness may be influenced by prey availability and the presence of intraguild predators. Further research on the impact of these interactions in natural agroecosystems is necessary to optimize the use of these species in pest management strategies.