桔小实蝇和番石榴实蝇幼虫取食阶段的种内竞争

种内竞争是实蝇的重要生态学特性。本文研究比较了近缘种桔小实蝇Bactrocera dorsalis(Hendel)和番石榴实蝇B.correcta(Bezzi)在幼虫人工饲料中种内竞争的密度效应。研究结果显示,桔小实蝇和番石榴实蝇都有密度过低效应,均表现出发育历期较长、蛹较轻和成活率较低;结合蛹重和成活率两个重要参数指标,明确了桔小实蝇和番石榴实蝇的最宜密度均在5-20头虫/10 g饲料;不同生长参数之间的变化均有一定的正负相关性。当种群密度超过最宜密度,桔小实蝇和番石榴实蝇均有明显的种内竞争现象,随着种群密度的升高,种内竞争越激烈。其主要表现为化蛹率和羽化率不断下降、幼虫历期逐渐缩短、蛹历期不断延长和蛹逐渐变小;当100头虫/10 g饲料时,桔小实蝇和番石榴实蝇成活率从86.00%±4.2688%和86.00%±4.1096%分别下降到60.08%±2.5166%和76.33%±2.2333%。桔小实蝇和番石榴实蝇的种内竞争的密度效应极具相似性,推测这两种实蝇有类似的种群调节机制,但番石榴实蝇的幼虫比桔小实蝇的拥有更强的抗拥挤能力。

Intraspecific competition between Bactrocera dorsalis (Hendel) and B. correcta (Bezzi) (Diptera: Tephritidae) during larval stage

Intraspecific competition is one of the major ecological features of Tephritidae. This study explored Bactrocera dorsalis (Hendel) and B. correcta (Bezzi) (Diptera: Tephritidae) density effect of intraspecific competition in their larval artificial feed. This study showed that B. dorsalis and B. correcta had effect of undercrowding, its main features were longer developmental duration, lighter pupa, lower survival rate. Through consulting the two parameters of weight of pupa and survival rate, most appropriate density of B. dorsalis and B. correcta was 5-20 heads /10 g artificial feed. In addition, changing of these growth parameters had a certain positive and negative correlation. When their population density exceeded most appropriate density, intraspecific competition would be constantly distinct. Specific performances were with the increase of density, percentage of pupation and eclosion rate decreased continuously, development period of larvae shortened and development period of pupa prolonged little by little, weight of pupa lightened gradually. When their population density were 100 heads /10 g artificial feed, survival rate of B. orsalis and B. correcta from 86.00%±4.2688% and 86.00%±4.1096% dropped respectively to 60.08%±2.5166% and 76.33%±2.2333%. B. dorsalis and B. correcta had similar density effect, so their population regulation mechanism was possibly consistent, but the B. correcta larvae had more competent to resist crowd.