Age-Stage, Two-Sex Life Table, Oviposition Rhythms of Zeugodacus cucurbitae and Zeugodacus tau

Abstract

Zeugodacus tau has attracted global attention in recent years due to its population expansion and invasion of new territories, as this species shares a similar host range with Zeugodacus cucurbitae. The objective of the present study was to evaluate the basic biological differences between these two insects. Age-stage and two-sex life tables of Z. cucurbitae and Z. tau were established for individuals reared on zucchini fruit at a constant temperature of 25°C. Moreover, the oviposition period of the two insects was completely observed. The results demonstrated that the intrinsic rate of increase (r) and finite rate of increase (λ) of Z. cucurbitae were greater than those of Z. tau. Additionally, the duration of each developmental stage and the average lifespan of Z. cucurbitae were significantly shorter than those of Z. tau, while its survival rate was significantly greater. Notably, male individuals of both species presented longer lifespans than their female counterparts. The reproductive values of Z. cucurbitae and Z. tau initially increased but subsequently decreased with age, peaking at 46 d and 65 d, respectively. The population size of Z. cucurbitae was significantly larger than that of Z. tau on day 90. Oviposition pattern analysis revealed that the oviposition period of Z. cucurbitae exhibited a unimodal distribution, whereas the oviposition period of Z. tau displayed a bimodal distribution. Further investigation revealed that during the first 30 days, the oviposition rate was significantly negatively correlated with female fly longevity, and Z. cucurbitae presented a significantly greater oviposition rate than Z. tau during this period. In summary, the findings of this study suggest that under identical environmental conditions, Z. cucurbitae has strong population growth potential, providing critical foundational data for the integrated management of these two pest species.