Effects of Survival Rate and Fecundity on the Intrinsic Rate of Increase of Helicoverpa Armigera (Hübner) (Lepidoptera: Noctuidae)

存活率及繁殖率對玉米穗蟲Helicoverpa armigera（Hübner）內在增殖率的影響

陳樂(Ratna K. Jha) ； 齊心(Hsin Chi) ； 唐立正(Li-Cheng Tang)

《台灣昆蟲》 32卷3期 (2012/09) Pp. 223-235

https://doi.org/10.6661/TESFE.2012013

摘要

本研究分析飼養於25°C人工飼料、甜玉米、蘆筍，以及29°C人工飼料的玉米穗蟲生命表，探討存活率與繁殖率對內在增殖率影響。縮減內在增殖率（the curtailed intrinsic rate, rδ）顯示了存活率及繁殖率對內在增殖率的影響。利用年齡齡期兩性生命表理論去估算玉米穗蟲的縮減增殖率，其範圍由負值至正值，最終等同於內在增殖率。累計貢獻值（the cumulative contribution, ry）則為個體存活至年齡y時對內在增殖率貢獻的描述值。累計貢獻值（ry）的範圍由0至r，但其並非一內在增殖率。使用固定卵孵化率開始進行玉米穗蟲生命表研究時，群體包含未受精卵，忽略卵孵化率而利用總產卵數計算繁殖率時，無法反應出玉米穗蟲真正的生物學特性。更確切的說，此方式會降低存活曲線、提高繁殖曲線，並導致估算出非常高的生命表族群參數，這將會降低使用內在增殖率評估玉米穗蟲在不同環境條件下適存性的可信度。因此，我們建議使用孵化卵數計算繁殖率。此外，在數據分析上應使用年齡齡期兩性命表以便能更精準地包含性比率、卵孵化率及發育隨年齡之變化。

關鍵字

玉米穗蟲 ； 性比 ； 孵化率 ； 縮減增殖率

並列摘要

The life history data of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) kept at 25°C on an artificial diet, on hybrid sweet corn, and on asparagus, as well as those kept at 29°C on an artificial diet were analyzed to assess the effects of survival rate and fecundity on the intrinsic rate of increase (r). The curtailed intrinsic rate (rδ) describes the effects of survivorship and fecundity on the intrinsic rate of increase. The curtailed intrinsic rate of H. armigera was estimated by applying the age-stage, two-sex life table theory, and ranged from negative to positive and finally became equal to the intrinsic rate. The cumulative contribution (ry) is a descriptive value of the cumulative input of individuals surviving to age y to the intrinsic rate. The value of cumulative contribution (ry) ranges from zero to r, however, it is not an intrinsic rate. At the beginning of a life table study of H. armigera using a fixed hatch rate, a cohort consists of unfertile eggs, and calculating the fecundity from the total laid-eggs by ignoring their hatchability does not reflect the true biological characteristics of H. armigera. Rather, it shifts the survivorship curve downward, the fecundity curve upward, and provides very high estimates of the life table parameters. In addition, it reduces the reliability of the estimate of the intrinsic rate of increase to be used as an indicator to evaluate the performance and fitness of H. armigera under variable conditions. Therefore, we recommend that the fecundity be calculated using the number of viable eggs. In addition, the age-stage, two-sex life table should be used in order to accurately analyze the data to encompass the age-specific variation in sex ratio, hatchability, and development in the analysis.

並列關鍵字

Helicoverpa armigera ； sex ratio ； hatchability ； curtailed intrinsic rate