Dietary effects on the development and population dynamics of the Thelazia callipaeda vector Phortica okadai revealed by age-stage, two-sex life table analysis

BACKGROUND: Phortica okadai (Diptera: Steganinae) is the primary vector of the zoonotic eyeworm Thelazia callipaeda (Nematoda: Spirurida). However, standardized laboratory rearing protocols for this vector are still lacking, which limits research on its biology and vector competence. METHODS: We evaluated the effects of five diets (fermented apple, pear, banana, and two artificial diets) on life history traits of P. okadai using age stage, two sex life table analysis under controlled conditions (28 ± 1 °C, 75 ± 5% RH, 14:10 h L:D). Life table parameters and population dynamics were analyzed with TWOSEX-MSChart and TIMING-MSChart (100,000 bootstrap replicates). RESULTS: All tested diets supported complete development. Fermented pear yielded the shortest pre adult duration (17.34 days), the highest fecundity (116.6 eggs per female), and the greatest intrinsic rate of increase (r = 0.0902/day). Population projection showed that 10 initial eggs on fermented pear produced more than 1,200 adults within 90 days, which was approximately 10 fold higher than on other diets. CONCLUSIONS: Fermented pear is the most suitable substrate for establishing laboratory colonies of P. okadai. These findings facilitate vector competence studies and indicate that pear orchards are potential high risk habitats for T. callipaeda transmission, supporting targeted One Health surveillance and control.