H. Fujimoto et al., REPRODUCTIVE INTERFERENCE BETWEEN PANONYCHUS-MORI YOKOYAMA AND PANONYCHUS-CITRI (MCGREGOR) (ACARI, TETRANYCHIDAE) IN PEACH ORCHARDS, Applied Entomology and Zoology, 31(1), 1996, pp. 59-65
The reproductive interference between Panonychus mori YOKOYAMA and P.
citri (McGREGOR) was studied in peach orchards, where they coexisted.
The abundance of the two species differed greatly among individual pea
ch trees, but the seasonal population trends were similar to each othe
r: populations remained at very low densities from May to July, and th
ereafter began to increase, reaching peaks in October. Ineffective fem
ales (females that produced no female offspring), resulting from the i
nterspecific matings between the two species, were observed in both sp
ecies on the trees where they coexisted. The degree of reproductive in
terference varied depending on the ratio of the densities of the two s
pecies on individual trees, and was higher on P. mori by P. citri than
vice versa. Furthermore, the proportion of females from overwintered
eggs of P. mori collected from trees with a mixture of the two species
was very low. These results seem to partially explain why P. mori can
not extend its distribution to lower latitudes where climatic conditio
ns are favorable for the species.