幼虫密度对桑螟生长发育和繁殖的影响

Effects of larval density on the growth,development and reproduction of the mulberry borer,Diaphania pyloalis(Lepidoptera:Pyralidae)

【目的】本研究旨在了解桑螟Diaphania pyloalis幼虫不同饲养密度对其生长发育和繁殖的影响。【方法】本研究测定了室内同一条件下5个幼虫密度(130,650,1300,1950和2600头/m^(2))下桑螟生长发育和繁殖指标,包括发育历期、幼虫存活率、化蛹率、成虫羽化率、蛹重、产卵期、单雌产卵量等。【结果】幼虫密度对桑螟的生长发育和繁殖均产生不同程度影响,幼虫密度偏低或偏高都不利于桑螟生长发育和繁殖。其中以1300和1950头/m^(2)2种幼虫密度下的桑螟幼虫生长发育和成虫繁殖状态均最佳且两密度下各项指标无明显差异,1300头/m^(2)密度下,桑螟的幼虫历期、蛹历期和成虫历期分别为11.32,6.33和5.31 d;1950头/m^(2)密度下,桑螟的幼虫历期、蛹历期和成虫历期分别为11.50,6.00和5.47 d。1300头/m^(2)幼虫密度下,桑螟化蛹率、成虫羽化率和幼虫存活率分别为86.67%,100%和86.67%,1950头/m^(2)幼虫密度下,桑螟的化蛹率、成虫羽化率和幼虫存活率分别为84.44%,94.74%和80.00%。1300和1950头/m^(2)幼虫饲养密度下桑螟成虫产卵期均达到2.00 d以上、单雌产卵量均达到55.00粒以上、卵孵化率均达到90.00%以上,与其他幼虫密度下的值均存在显著性差异。另外,幼虫密度与桑螟幼虫存活率表现为极显著相关性。【结论】幼虫密度是影响桑螟生长发育和繁殖的重要因子,桑螟幼虫密度为1300头/m^(2)或1950头/m^(2)时,有利于桑螟室内种群高效建立。

【Aim】This study aims to understand the effects of different larval rearing densities of the mulberry borer,Diaphania pyloalis on their growth,development and reproduction.【Methods】The growth,development and reproduction parameters including the developmental duration,larval survival rate,pupation rate,adult emergence rate,pupal weight,oviposition period and number of eggs laid per female of D.pyloalis reared at five different larval densities(130,650,1300,1950 and 2600 individuals/m^(2))were determined under the same condition in the laboratory.【Results】Larval density had influences on the growth,development and reproduction of D.pyloalis to varying degrees,and low or high larval density was not conducive to its growth,development and reproduction.There was no obvious difference in the growth,development and reproduction parameters of D.pyloalis reared at the larval densities of 1300 and 1950 individuals/m^(2),both with excellent performance.The larval,pupal and adult duration of D.pyloalis reared at the larval density of 1300 individuals/m^(2)were 11.32,6.33 and 5.31 d,respectively,and those reared at the larval density of 1950 individuals/m^(2)were 11.50,6.00 and 5.47 d,respectively.The pupation rate,adult emergence rate,and larval survival rate of D.pyloalis reared at the larval density of 1300 individuals/m^(2)were 86.67%,100%and 86.67%,respectively,and those reared at the larval density of 1950 individuals/m^(2)were 84.44%,94.74%,and 80.00%,respectively.When D.pyloalis larvae were reared at the densities of 1300 and 1950 individuals/m^(2),the oviposition periods of their adults reached more than 2.00 d,the numbers of eggs laid per female reached more than 55.00 grains,and the egg hatching rates were more than 90.00%,showing significant difference from those reared at the other larval densities.In addition,the larval density of D.pyloalis showed an extremely significant correlation with the larval survival rate.【Conclusion】Larval density is an important factor affecting the growth,development and reproduction of D.pyloalis,and when the larval density is 1300 individuals/m^(2)or 1950 individuals/m^(2),it is conducive to the efficient establishment of its indoor populations.