POPULATION ECOLOGY OF CINNABAR MOTH, TYRIA-JACOBAEAE L (LEPIDOPTERA,-ARCTIIDAE)
POPULATION ECOLOGY OF CINNABAR MOTH, TYRIA-JACOBAEAE L (LEPIDOPTERA,-ARCTIIDAE)
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DOI：
10.1007/bf00346293
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发表时间：
1971-01-01
期刊：
影响因子：
2.7
通讯作者：
DEMPSTER, JP
中科院分区：
文献类型：
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作者：
DEMPSTER, JP
本文介绍了影响英国朱砂蛾丰度和分布的因素的研究结果。这项研究的主要部分是在诺福克郡威廷希思的一个飞蛾种群上进行的。这是一片被兔子过度放牧的沙质荒地。在这里，飞蛾的数量波动剧烈，并周期性地在大面积上完全落叶它的食物植物（黑草，黑草）。这种情况分别发生在1960年、1961年、1967年和1968年。自1966年以来，对蛾的数量进行了详细的研究，并提供了五年的生命表。成虫的繁殖力在不同年份差别很大。这主要是由于幼虫密度的变化导致成虫大小的波动。相比之下，成虫死亡率和分散对繁殖力影响不大；尽管有一些证据表明，扩散与密度有关。因为一代产卵的数量取决于上一代的大小，所以繁殖力往往是一个延迟的密度依赖因素。卵期死亡率低，但幼幼虫死亡率高，主要是由于节肢动物的捕食。随着毛毛虫的成长，它们对这种捕食产生了免疫力。它们是脊椎动物的天敌。一种叫做Apanteles popularis的寄生虫幼虫会杀死许多完全长大的幼虫。然而，寄生率最高的时候，蛾的密度却最低，因此，在过去的五年里，它已经成为了一个与密度相反的依赖因素。1967年，它们的数量变得如此之大，以至于豚草的叶子完全脱落，大约20%的毛虫死于饥饿。第二年，由于前一年落叶的影响，种群仍然很大，而ragwort植株很小。食物在季节早期就耗尽了，大约50%的幼虫饿死了。由于饥饿的主要影响，幼虫的总死亡率往往与密度有关。在化蛹时或化蛹后死亡率很高，这被认为主要是由于鼹鼠（Talpa europaea）的捕食。蛹死亡率似乎与密度无关。人口的增长受到粮食供应的限制。饥饿导致种群数量锐减，1969年每150平方米只产62只蛋，而前两年分别为17110和16493只。在这次崩溃之后，种群的恢复速度取决于ragwort植物的快速恢复。由于1968年夏季潮湿，由于根芽再生，植物数量在落叶后实际上增加了。尽管该地区在1967年和1968年都没有生产种子。在食物在季节早期耗尽的年份里，唯一似乎可以缓冲种群免于灭绝的因素是飞蛾和ragwort种群的异质性。最早的个体设法在那些存活时间最长的豚草斑块中获得足够的食物。只有在某些地区才会出现较大的数量波动。其他种类的飞蛾维持在低密度，从不吃光它们的食物供应。一些数据来自蒙克斯伍德这样的种群。这个地点是在一个重粘土的土壤上，兔子放牧不像在Weeting那么明显，而且ragwort只在低密度的情况下出现。茂盛的植被支持着大量的节肢动物捕食者，这些捕食者比在维廷发现的幼虫的比例更高。蛹成活率也很低，可能是由于土壤涝渍。蛹可以承受相当大的干燥，但过多的水分很快就会导致…
This paper describes the results of a study of the factors determining the abundance and distribution of the Cinnabar Moth in Britain. The main part of the study was on a population of the moth at Weeting Heath in Norfolk. This is an area of sandy heath which is heavily overgrazed by rabbits. Here the moth fluctuates violently in number and periodically it completely defoliates its food plant (ragwort,Senecio jacobaeaL.) over large areas. This happened in 1960, 1961, 1967, and 1968.Since 1966, the numbers of the moth have been studied in detail and Life Tables are presented for five years.Adult fecundity varies considerably between years. This is due mainly to fluctuations in adult size resulting from changes in larval density. By comparison adult mortality and dispersal have little effect on fecundity; although there is some evidence to suggest that dispersal is density dependent. Because the number of eggs laid in one generation depends on the size of the previous generation, fecundity tends to be acting as a delayed density dependent factor.Mortality is low during the egg stage, but is high amongst young larvae, due mainly to arthropod predation. As the caterpillars grow they become immune from this predation. They are distasteful to vertebrate predators.A larval parasite,Apanteles popularis, kills many of the fully grown larvae. The highest rates of parasitism have coincided with the lowest densities of the moth, however, so that over the five years it has acted as an inverse density dependent factor.In 1967, the population became so large that the ragwort was completely defoliated, and about 20% of the caterpillars died from starvation. In the following year the population was still large and the ragwort plants were small, owing to the effects of defoliation in the previous year. Food ran out early in the season and about 50% of the larvae starved. Because of the overriding effect of starvation, total larval mortality tends to be density dependent.Mortality is high at, or immediately after, pupation and this is thought to be due primarily to predation by moles (Talpa europaea). Pupal mortality does not appear to be density dependent.The upward growth of the population is limited by food supply. Starvation led to a population crash, so that in 1969 only 62 eggs/150 m2were laid compared with 17110 and 16493 in the previous two years. The rate of recovery of the population after this crash was dependent upon the rapid recovery of the ragwort plants. Owing to the wet summer in 1968, plant numbers actually increased after defoliation, due to regeneration from root buds. This was in spite of the fact that no seed was produced in the area in either 1967 or 1968.The only factor which appears to buffer the population against extinction in years when food runs out early in the season, is the heterogeneity within the moth and ragwort populations. The earliest individuals manage to obtain sufficient food in those patches of ragwort which survive longest.Large fluctuations in number only occur in some localities. Other populations of the moth persist at low density and never eat out their food supply. Some data are presented from such a population at Monks Wood. This site is on a heavy clay soil, rabbit grazing is less marked than at Weeting, and ragwort occurs only at a low density. The lusher vegetation supports a very large population of arthropod predators and these take a higher percentage of the young caterpillars than was found at Weeting. Pupal survival is also low due probably to waterlogging of the soil. Pupae can withstand considerable desiccation, but excessive moisture soon leads …