甜菜夜蛾交配行为和能力

在(27±1)℃，光周期L14∶D10的条件下对甜菜夜蛾I>Spodoptera exigua的交配行为及能力进行了研究。结果表明：成虫在羽化当晚即可进行交配，交配率以羽化后头三个晚上的较高(>82%)，但从第4天起则显著下降。成虫一天中的交配时间出现于23:30～05:30之间，交配高峰出现在01:30～02:30和03:00～04:00 之间, 其中以第1高峰的发生频率较高。成虫交配持续时间从22～191 min不等，但以30～60 min的为多(40.8%, n=97), 60～90 min的次之(19.4%)，超过180 min的较少(10.2 %)。另外，交配持续时间与蛾龄紧密相关。蛾龄越大，交配持续的时间越长，且差异显著。雄蛾一生的交配能力由1～11次不等，但受性比的影响显著：在性比为1∶1的条件下，雄蛾平均交配次数仅为3.0 次，而在2♀∶1♂至5♀∶1♂时，则增加到5.1～6.0 次。雌蛾交配比例及次数受性比的影响也很大：没有交配的雌蛾比例从1∶1时的8.3%增加到5♀∶1♂时的32%，仅交配一次的比例从16.7%增加到38.7%，而交配≥5 次的比例则从 25%下降到0。最后，对这些结果在甜菜夜蛾防治中应用的可能性进行了讨论。

Mating behavior and capacity of the beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae)

ating behavior and capacity in the beet armyworm, Spodoptera exigua (Hübner) were investigated under laboratory conditions (27℃ ±1℃, L14∶D10). The results indicated that both males and females were able to mate on the first night, and all males and females observed completed their mating on the second night after emergence. The mating rates on the first three nights were relatively high (>82%), and decreased significantly after the fourth night (<50%). Daily mating activity occurred from 23:15 to 05:30, and peaked from 01:30 to 02:30 and from 03:00 to 04:00, with a higher frequency in the first peak. Mating duration of the moths lasted from 30 to 60 minutes (40.8%, n=97), followed by 60 to 90 minutes (19.4%), and in some cases (10.2%) lasted more than 180 minutes. Furthermore, mating durations were highly associated with the moth age: in the older moths it lasted significantly longer than in the younger ones. Lifetime mating number for a male was from 1 to 11, with an average of 50 However, mating capacity of a male was significantly associated with operational sex ratio. The lifetime mating number of males was only 3.0 in average when a male was confined with one female, but increased to 5.1-6.0 when a male was confined with 2-5 females. On the other hand, the percentage and frequency of female mated were also tied to sex ratio. This could be demonstrated by the fact that the percentage of unmated female increased from 8.3% to 32%, and once mated females from 16.7% to 38.7%, at a sex ratio of 1:1 and 1♂:5♀, respectively, whereas the proportion of females that mated more than 5 times decreased from 25% to 0 under the same conditions. The significance of these findings for the application of sex pheromones to control the beet armyworm was discussed.