Intra- and inter-specific competition between two stone leek leafminer Liriomyza chinensis (Diptera: Agromyzidae) biotypes in Japan

Two stone leek leafminer Liriomyza chinensis (Kato) (Diptera: Agromyzidae) biotypes (A and B) were reared using the Japanese bunching onion Allium fistulosum L. cultivar, ‘Kujou futo’ and subjected to competition under laboratory conditions. Both biotypes were reared in single and mixed cultures in varying proportions. The present study aimed to determine the reproductive behavior of the two L. chinensis biotypes under laboratory conditions of 24.5 °C and a photoperiod of 15 h light: 9 h darkness. Therefore, 12 adult flies, consisting of 3 males and females from each biotype, were reared in mixed cultures. The results indicated that biotype B had a significantly higher number of eggs and more emerged adults in the next generation than those of biotype A. The proportion of F₁ adults was 1.6%. In the second experiment, six males and females from the different biotypes were subjected to inter-biotype mating for 2 days without oviposition substrates. Subsequently, a mature female from each biotype was allowed to lay eggs on A. fistulosum fresh leaves. The results revealed that no larvae hatched from the eggs of both biotypes. The number of eggs per plant from both biotypes was standardized to determine larval competition. The number of eggs and egg survival rates of biotype B were higher than those of biotype A, indicating that under 24.5 °C and 15 h light: 9 h darkness conditions, biotype B outcompetes biotype A.