Abundance of the Dominant Endosymbiont Rickettsia and Fitness of the Stored-Product Pest Liposcelis bostrychophila (Psocoptera: Liposcelididae)

Endosymbiotic bacteria are key factors that regulate the biological traits of <i>Liposcelis bostrychophila</i>. This study employed metagenomic methods to analyze the dominant species of symbiotic microorganisms associated with <i>L. bostrychophila</i>. By controlling the environmental temperature, we were able to manipulate the abundance of endosymbionts and establish populations with high, medium, and low levels of these bacteria. This allowed us to examine the fitness parameters of <i>L. bostrychophila</i> under different levels of endosymbiont abundance. The experimental results revealed that <i>L. bostrychophila</i> hosts 51 genera of symbiotic microorganisms, with <i>Rickettsia</i> being the dominant genus, accounting for 84.11% to 98.16% of the total share. Environmental temperature significantly affected the abundance of <i>Rickettsi</i>a, with notable differences observed during the adult stage of <i>L. bostrychophila</i>. A temperature gradient of 28 °C, 35 °C, and 37 °C was established, allowing for the classification of populations based on <i>Rickettsia</i> abundance into three categories: high-abundance populations (<i>LBhp</i>), medium-abundance populations (<i>LBmp</i>), and low-abundance populations (<i>LBlp</i>). The abundance of <i>Rickettsia</i> had a significant impact on the fitness of <i>L. bostrychophila</i>. Specifically, a high abundance of <i>Rickettsia</i> contributed positively to population fitness by increasing egg production, prolonging egg hatching time, enhancing lifespan, and improving both survival and reproductive rates. Therefore, the endosymbiont <i>Rickettsia</i> plays a crucial role in the growth and development of <i>L. bostrychophila</i>. In the future, our research will help further uncover the interactions between <i>Rickettsia</i> and its host, providing new perspectives for pest control and offering a better understanding of insect biology and ecology.