马尾松毛虫的光周期反应

马尾松毛虫Dendrolimus punctatus Walker和油松毛虫 Dendrolimus tabulaeformisTsai et Liu都属于长日照型昆虫。它们的光周期反应却存在着明显的差开。马尾松毛虫初龄幼虫对光照时数虽然敏感,可是只有在整个幼虫期都处在短光照周期条件下才能维持幼虫的滞育。 而且, 幼虫的滞育强度明显较弱,解除滞育所要求的条件也不如油松毛虫严格。在较高温度条件下,幼虫的滞育更不稳定,一般仅表现为生长的短暂停滞和幼虫历期的相对延长。温度和光周期还可影响到幼虫的存活和性比。马尾松毛虫幼虫呈典型的浅滞育现象。正是由于这一特性,在环境条件的影响下,长江沿岸省份不同年份马尾松毛虫二、三代分化的比例才有较大的波动,这直接关系着当地的种群动态,也是当年当地高虫口区二代虫能否成灾的关键。     

光周期对中华通草蛉自然越冬成虫及实验种群幼虫耐寒能力的影响

【目的】滞育诱导期进行短光照处理可影响昆虫耐寒性。为明确光周期对中华通草蛉Chrysoperla sinica (Tjeder)耐寒性的影响, 针对中华通草蛉滞育解除过程及非滞育虫态的耐寒性进行了一系列研究。【方法】测定了中华通草蛉自然越冬成虫的过冷却点（supercooling point, SCP）以及长光周期（15L∶9D）和短光周期（9L∶15D）条件下自然越冬成虫在滞育解除过程中在-12℃下的死亡率, 并测定了室内长、 短两种光周期下实验种群2龄和3龄幼虫的过冷却点（SCP）、 结冰点（freezing point, FP）以及-7℃下的死亡率。【结果】中华通草蛉12月份的自然越冬成虫SCP集中在-10~-14℃之间。SCP低于-12℃的个体占43.70%, 且-12℃处理1 d死亡率为62.00%。-12℃处理1 d条件下的长、 短光周期处理自然越冬成虫, 除处理0 d外, 长光周期处理死亡率均高于短光周期处理的, 且在处理15 （P=0.012）, 20 （P=0.01）和25 d （P=0.001）差异显著。中华通草蛉试验种群相同龄期幼虫在短光周期下的SCP和FP均高于长光周期下, 但差异不显著(P>0.05); 但在-7℃下, 2龄幼虫短光周期下的低温死亡率为67.00%±4.04%, 显著低于长光周期下的低温死亡率（78.00%±1.33%）（P=0.011）, 3龄幼虫短光周期条件下低温死亡率为24.33%±1.33%, 显著低于长光周期下的低温死亡率（53.00%±3.46%）（P=0.002）。【结论】中华通草蛉为结冰敏感型, 诱导滞育的短光照处理可提高其幼虫期及滞育解除过程中成虫的耐寒能力。     

草地螟阿格姬蜂的滞育诱导和滞育茧的低温贮藏

为了阐明环境因子对草地螟阿格姬蜂Agrypon flexorium (Thunberg)滞育诱导作用, 测定了5个光周期和4个温度处理对阿格姬蜂的滞育诱导和该蜂感受光周期的敏感虫态以及不同时间段低温贮藏对滞育虫茧的影响。结果表明： 在17~23℃、 光照时间10~14 h范围内, 随着温度的降低和光照时间的缩短, 滞育率明显提高。高温能抵消短光照对滞育诱导的影响, 在26℃下, 短光照不能诱导滞育。因此, 低温和短光照是诱导草地螟阿格姬蜂滞育的主要因子。草地螟阿格姬蜂感受滞育信号的敏感虫态为卵和1龄幼虫。卵和1龄幼虫感受滞育信号以后, 需要在滞育环境中发育到老熟幼虫才能全部进入滞育。将室内诱导的滞育茧在4℃左右环境条件下冷藏80 d, 成蜂的羽化率和寄生能力与没有冷藏的非滞育茧差异不显著, 冷藏120 d, 滞育茧仍有71.7%可以正常羽化。结果说明,可在17℃,光周期8L∶16D条件下对寄生后3 d内的草地螟Loxostege sticticalis幼虫进行滞育诱导, 滞育后的虫茧最佳贮藏时间为80 d, 不宜超过120 d。本研究为室内扩繁、 防止蜂源退化、 控制寄生蜂发育时间以便适时释放提供了参考依据。     

阿维灭幼脲对马尾松毛虫幼虫的毒力测定

运用阿维灭幼脲生物复合剂对3-4龄的马尾松毛虫幼虫进行毒力测定,用机率分析法求得马尾松毛虫的死亡率与阿维灭幼脲剂量对数—机率直线,建立毒力回归线。研究表明,25%阿维灭幼脲悬浮剂对3-4龄幼虫的致死中稀释浓度为49.6倍液,即LC50=5.04 mg.L-1;阿维灭幼脲悬浮剂与尿素混合剂对3-4龄的致死中稀释浓度为52.5倍液,即LC50=4.76 mg.L-1;25%阿维灭幼脲悬浮剂10倍稀释液对3-4龄马尾松毛虫幼虫的LT50为0.57 d,到50倍稀释液时LT50为7.35 d;25%阿维灭幼脲悬浮剂与尿素混合剂10倍稀释液对3-4龄马尾松毛虫幼虫的LT50为0.71 d,到50倍稀释液时LT为6.13 d,随着浓度稀释倍数的增加,致死中时间延长。研究结果可为今后马尾松毛虫的林间防治提供科学依据。     

亚洲玉米螟滞育诱导外源性因子研究

研究了食料、温度、光周期等外源性因子对亚洲螟滞育的影响,试验证明,食料性质对其滞育诱导影响显著,取食玉米雌的幼虫以滞育诱导光周反应的敏感性强于取食棉铃的幼虫,在一定范围内,食料中可溶性糖含量增加可促进幼虫的滞育诱导,而粗蛋白含量的增加则具有抑制滞育诱导的作用,两者的互作效应不显著。高温抑制滞育诱导,你 促进滞育诱导。短光周对幼虫的滞育诱导无特定的敏感龄期,但以３龄与２龄对短光周刺激敏感性较强,包光     

甜菜夜蛾增殖马尾松毛虫质型多角体病毒防治应用研究

【目的】研究替代寄主甜菜夜蛾Spodopteraexigua增殖的Se-DpCPV及其复合剂对马尾松毛虫Dendrolimus punctatus的防治效果,为进一步研究马尾松毛虫林间大规模防治提供依据。【方法】在室内利用接种不同浓度病毒的松针饲喂马尾松毛虫幼虫,比较替代寄主增殖的Se-DpCPV和野生型Dp CPV毒力能力以及Se-DpCPV对不同龄期马尾松毛虫幼虫毒力水平;同时,在林间利用固定翼植保无人机喷洒不同浓度Dp CPV及其复合剂,测定各组对第1代马尾松毛虫幼虫的防治效果。【结果】甜菜夜蛾增殖的Se-DpCPV和野生型Dp CPV对马尾松毛虫幼虫具有同样的感染致病能力,对马尾松毛虫3龄幼虫半数致死浓度LC50分别为4.73×103PIB/m L和3.36×103PIB/m L,二者毒力差异性不显著(P=0.107>0.05)。Se-DpCPV对马尾松毛虫2-5龄各龄幼虫半数致死浓度LC50分别为2.03×103、4.73×103、1.05×104、3.85×104 PIB/mL。当Se-DpCPV林间用量分别为375亿、750亿和1500亿PIB/hm2时,Se-DpCPV+3.2%阿维菌素复合剂防治组马尾松毛虫校正死亡率为86.05%、90.70%和94.19%,对马尾松毛虫的林间防治效果显著高于Se-DpCPV+25%灭幼脲复合剂(66.28%、72.09%和79.07%)和Se-DpCPV(59.30%、63.95%和70.93%)。活虫Dp CPV感染率最低为80.00%,最高可达93.33%。Se-DpCPV与3.2%阿维菌素、25%灭幼脲复配,比单独使用两种药剂防治效果至少分别提高17.45%和33.72%。【结论】在林间马尾松毛虫大暴发时,在马尾松毛虫3龄以下幼虫期,使用Dp CPV+3.2%阿维菌素复合剂(750亿PIB/hm2,7.5 mL/hm2)在短时间内迅速降低虫口基数,同时起到持续控制的效果。     

光周期和温度对桃小食心虫滞育的影响

桃小食心虫在辽西兴城地区为二化性具有兼性滞育的昆虫。第一代幼虫的一部分及第二代幼虫的全部老熟脱果后,在表土作扁圆形的“冬茧”以滞育状态越冬,整个越冬期长达9—10个月。 在田间,7月下旬脱果的幼虫,就有少数个体进入滞育:随着脱果日期的延迟,进入滞育的个体增多。8月20日以后脱果的幼虫,进入滞育的个体锐增,8月底脱果者,基本全部进入滞育,当年不再发生第二代。 室内控制条件下进行的试验证明,在中位温度下,滞育与否主要决定于幼虫果内发育期间昼夜光照时数:当每天光照为12小时以下时,脱果后的幼虫,基本上全部进入滞育。在每天光照15小时下发育的幼虫,基本上不滞育。但随着光照时间的继续延长,滞育个体又大大增加。 在25℃恒温下,临界光周期约为14小时20分,但此临界光周期并不是一个固定不变的数值,而是随着温度的变化发生有规律的变动;在一定的温度范围内,温度提高,临界光周期缩短;温度降低,临界光周期延长。 幼虫在果内发育时间,对短光照反应均显示出一定程度的敏感性,但是,仍然可以看出,感受光照反应的时期主要是蛀果后取食的前10天。幼虫连续感受短光照的时间愈长,则滞育率愈高。光周期诱发滞育是不可逆的。 关于温度与滞育的关系,试验结果初步表明,高温在一定的程度上抑制短光照对滞育的作用;低温在一定程度上控制长光照对滞育的作用。 解除滞育的试验初步证明,低温是解除滞育必需的条件,滞育幼虫在10℃的温度条件下,经历两个多月,即有60%的个体解除了滞育。完成滞育发育的适宜温度范围可能在5—10℃之间。     

山楂叶螨滞育的初步研究

本文采用海绵水盘法研究了山楂叶螨Tetranychus viennensis Zacher的滞育与温度、光照和寄主营养等环境因子的关系。结果表明21℃下,临界光周期为12 h 32 min,光敏感螨态为幼螨至第二若螨之间的连续两个螨态,单独一个发育阶段对短光照不敏感或仅有微弱的感应。在相同寄主（梨树）叶片上,病叶和老叶诱导的滞育率比嫩叶高,分别为69.7%、55.3%和20%。相同叶片,短光照(12.5 h/d)条件下随螨密度的增大滞育率升高。相同短光照下,低温促进滞育,在15℃、18℃和21℃下滞育率分别为100%、93.1%和66.7%;高温（24℃）抑制滞育,滞育率仅为13.3%;温度为27℃时不滞育。     

光周期对大草蛉(Chrysopa pallens)滞育及发育的影响

在22℃条件下,研究大草蛉对光周期的敏感性,结果表明:大草蛉属短日照滞育型,在短光照条件下饲养获得的预蛹进入滞育状态,诱导预蛹滞育的临界光周期为10.5L-13.5D到11L-13D.2龄幼虫期是诱导预蛹滞育的敏感虫期,只有当2龄幼虫期处于短光照条件下时才能进入滞育状态.1龄和3龄幼虫期也在滞育诱导条件下进行滞育诱导,能够提高滞育率.光周期对大草蛉幼虫历期及预蛹重的影响研究结果表明:光周期对幼虫历期有一定的影响,特别对2龄幼虫期的影响比较明显.幼虫期的光周期条件影响预蛹的重量,滞育预蛹的重量显著高于非滞育预蛹.     

光周期和温度对草地螟滞育诱导的影响

草地螟Loxostege sticticalis以老熟幼虫滞育越冬。在室内通过人工诱导的方法对其滞育的光周期和温度诱导条件进行了研究。结果表明:草地螟是一种典型的长日照发育型种类。光周期、温度及其交互作用均对草地螟滞育诱导具有重要影响, 其中光周期起主导作用, 温度伴随着光周期起作用。对幼虫滞育诱导最有效的光周期是L12∶D12; 随着温度的升高, 临界光周期呈缩短趋势（18℃除外）。18, 22, 26和30℃条件下幼虫滞育的临界日长依次为13.97, 14.48, 13.92 和12.88 h。光敏感实验揭示:21℃时草地螟对光照反应最敏感时期为幼虫孵化后的11～17 d（约5龄幼虫）, 但孵化后7～11 d（约4龄幼虫）的短光照积累对提高滞育率也有重要作用, 可以将滞育率从40.0%提高到90.0%。     

高温对环带锦斑蛾幼虫滞育的抑制作用

本文报道了高温（31℃）对环带锦斑蛾幼虫滞育发生的抑制作用。当幼虫暴露于31℃ 时,所有个体都继续发育,与光周期无关。在诱导滞育的光周期条件(L12∶D12)下,光期的高温配合不同的暗期低温（15～28℃）,导致几乎所有个体滞育,但当暗期为5℃时,滞育率反而下降;相反,当光期的低温配合不同持续时间的暗期高温（31℃）时,则几乎所有的个体都继续发育,这说明高温在暗期发挥着重要的作用。在暗期给予不同时间长度（2、4、 6、8、10、12 h）的高温处理,结果表明一个2 h的高温处理就能有效地抑制滞育的发生。在暗期的不同时间给予4 h高温处理,显示了幼虫在暗期开始后的第一个4 h (18:00～22:00 )对高温最敏感,完全抑制了滞育的发生。最后讨论了高温调节滞育机制在该虫生活史上的适应意义。     

Developmental changes in dopamine levels in larvae of the fly Chymomyza costata: comparison between wild-type and mutant-nondiapause strains

Dopamine and two related catecholamines, L-3,4-dihydroxyphenylalanine (DOPA) and N-acetyl dopamine (NADA), were analyzed in whole body and tissue samples taken throughout late larval development of the drosophilid fly Chymomyza costata, which enters facultative diapause as a mature 3rd instar larva in response to short photophase. Wild-type (W) and mutant-nondiapause (M) strains reared under diapause inducing (d) and preventing (nd) photophases were compared. Developmental changes in the whole body of dopamine levels showed some general features irrespective of fly strain and rearing conditions: sharp major peaks during moult from second to third instar larva and during pupariation; lower minor peaks around the middle of both 2nd and 3rd instars. Significant differences between the strains and conditions were also found: dopamine levels were lower throughout the 2nd instar and during the 2nd to 3rd instar moult of mutant strain larvae (M/d) as compared to wild-type larvae (W/nd and W/d); while the late 2nd and late 3rd instar larvae destined to diapause (W/d) maintained relatively high dopamine concentrations, their counterparts destined to continuous development (W/nd and M/d) significantly decreased dopamine levels prior to the 2nd to 3rd instar moult or pupariation. Possible relationship between the dopamine levels and diapause induction/onset in C. costata larvae is discussed. Integument contained more than 90% of the dopamine found in the whole body. The gut and central nervous tissues showed relatively low pools of dopamine, only trace amounts were detected in haemolymph and no dopamine was found in fat body. DOPA levels were low and stable throughout larval development of both W and M strains and under both conditions. NADA levels peaked during second halves of 2nd and 3rd instars of both strains, then dropped to trace levels and were elevated again during 2nd to 3rd instar moult as well as in tanned prepupae. No elevation of NADA levels was recorded in 3rd instar W/d larvae which entered diapause.     

稻纵卷叶螟幼虫驯化产生的热适应能力的继代效应

摘要: 【目的】在全球不断变暖背景下,昆虫受到热胁迫的频率不断增加。短期内反复受到热胁迫会使昆虫产生热适应性,但是昆虫热驯化所产生的耐热能力的传代效应还不完全清楚。稻纵卷叶螟Cnaphalocrocis medinalis是水稻上的重要害虫,对其幼虫在特定温度下进行几代热锻炼可提高其对高温的适应能力。本研究旨在摸清稻纵卷叶螟热适应的传代能力,为在全球变暖形势下以温度因子预测其种群发展趋势提供指导。【方法】将实验室内分别经39℃和41℃连续锻炼30代建立的稻纵卷叶螟热锻炼品系HA39和HA41以及非锻炼品系HA27的1-5龄期幼虫在不同温度(36℃和41℃)下进行不同时长(1~144 h)的暴露处理,调查幼虫的存活率,确定热锻炼品系幼虫的耐热能力;采用两品系间杂交实验测定HA39和HA27各交配组合的繁殖力及后代3龄幼虫的耐热能力;对HA39停止高温锻炼,并测定停止锻炼2代后3龄幼虫的耐热能力。【结果】稻纵卷叶螟3龄幼虫经历多代次短期热锻炼不仅可提高该龄幼虫的高温适应力,而且可提高其他龄期幼虫对特定高温的耐受能力,表现为HA39和HA41在36或41℃下处理特定时长的存活率显著高于HA27。锻炼高温的不同,幼虫获得的热耐受能力也有差异。39℃下锻炼可提高4龄幼虫在36℃下暴露2和4 d以及5龄幼虫在41℃下暴露5和6 h时的存活率,但41℃下锻炼则不可。HA39和HA27的自交及杂交后代的繁殖力之间均无显著差异,杂交后代3龄幼虫在41℃下处理5和6 h时的存活率与HA39自交后代的相当,并且显著高于HA27自交后代的,幼虫通过热锻炼获得的耐热能力可从亲本遗传给后代。停止热锻炼2代后,在39℃下处理4 h时HA39 3龄幼虫的存活率显著高于HA27的,但39℃下其余处理时间以及36和41℃下处理1~7 h HA39 3龄幼虫的存活率均与HA27的无显著差异,表明幼虫热锻炼产生的耐热能力在停止锻炼后2代仍可部分保持。【结论】稻纵卷叶螟幼虫的热适应能力具有继代效应。经过长期的气候变暖适应后,稻纵卷叶螟种群的热适应能力很可能在不断增强,从而夏季高温对其种群的抑制作用减弱,其种群暴发频率增加。     

大分舌蜂不同龄期幼虫及滞育预蛹肠道细菌 群落多样性及其差异

【目的】基于昆虫肠道微生物在宿主健康与调控宿主生长发育中发挥着重要作用,本研究旨在对大分舌蜂Colleles gigas不同龄期幼虫及滞育预蛹肠道细菌群落多样性及其差异进行初步探究。【方法】利用野外采集的大分舌蜂1-5龄幼虫及滞育预蛹,提取肠道内容物细菌DNA进行16S rRNA的V3-V4基因片段PCR扩增,利用IlluminaMiseq二代高通量测序技术进行测序。依据获得的序列数据,利用生物信息学方法分析大分舌蜂幼虫和滞育预蛹肠道细菌的组成、丰度和多样性。【结果】大分舌蜂幼虫肠道细菌菌群共检测到15门,23纲,43目,80科,128属的细菌,其中最主要的门是变形菌门(Proteobacteria)(占93.74%),最主要的目是立克次氏体目(Rickettsiales)(占68.68%),最主要的科是无形体科(Anaplasmataceae)(占68.64%),最主要的属是沃尔巴克氏体属Wolbachia(占68.64%)。Beta多样性分析结果显示,细菌群落变化与幼虫发育有关,显示出低龄组(1-3龄幼虫)、高龄组(4-5龄幼虫)和滞育预蛹组3个水平。Alpha多样性分析显示,滞育预蛹组细菌多样性与高龄组和低龄组的存在显著差异,而高龄组与低龄组间差异不显著。线性判别分析结果显示,滞育预蛹组与低龄组都存在显著优势菌纲,分别是α-变形菌纲(Alphaproteobacteria)和γ 变形菌纲(Gammaproteobacteria),而高龄组不存在显著优势纲。在目水平,肠杆菌目(Enterobacteriales)和假单胞菌目(Pseudomonadales)为低龄组优势目,立克次氏体目(Rickettsiales)为滞育预蛹组的优势目。在科水平,肠杆菌科(Enterobacteriaceae)和莫拉氏菌科(Moraxellaceae)为低龄组的优势科,无形体科(Anaplasmataceae)为滞育预蛹组的优势科。在属水平,低龄组优势属为肠杆菌属 Enterobacter和不动杆菌属Acinetobacter,滞育预蛹组优势属为沃尔巴克氏体属 Wolbachia。功能基因注释结果也显示出这3个组的特点。【结论】大分舌蜂不同龄期幼虫及滞育预蛹肠道细菌群落存在显著差异,从低龄组向高龄组再到滞育预蛹组,细菌多样性逐步降低,这可能与其进食特点以及肠道微生物驱动对肠道环境适应有关。本研究为土壤筑巢独栖野生蜜蜂肠道微生物研究奠定基础,也为此类野生蜜蜂的保护提供新的角度与方向。     

Effects of photoperiod and temperature on the termination of diapause in the univoltine seed wasp Eurytoma plotnikovi

Abstract Mummified pistachios containing fully grown diapause larvae of Eurytoma plotnikovi Nikol'skaya (Hym., Eurytomidae) were collected in early August and late September in coastal northern Greece and subjected to various photoperiod and temperature treatments, then maintained at 19 or 26°C and a long-day (LD 16:8 h), a changing, or a short-day (LD 10:14 h) photoperiod until pupation. In larvae of early August (beginning of diapause) subjected for 20 weeks to 19°C under a long, a changing, or a short photophase, followed by 19°C and a long photophase, 50% of the larvae pupated after 24, 18 and 13 weeks respectively. After exposure for 20 or even 12 weeks to a short photophase and low temperatures (10 or 4°C), pupation occurred after only 7–8 weeks and was more synchronous. The ranges of temperature for diapause development and post-diapause morphogenesis overlap. After exposure for 12 weeks to short days and low temperature, larvae of late September pupated much sooner under long days than under short days and sooner at 26° than at 19°C. E.plotnikovi depends on both temperature and photoperiod for diapause development, low temperature having a strong favourable effect on the earlier part and long day on the later part of diapause. In a few larvae of another pistachio seed wasp, Megastigmus pistaciae Walker, after a long enough period of low temperatures, diapause was terminated normally at 26°C and long days, or at 19°C and long or short days.     

Juvenile hormone changes associated with diapause induction, maintenance, and termination in the beet webworm, Loxostege sticticalis (Lepidoptera: Pyralidae)

At 22°C and under a long-day photoperiod of L:D 16:8, all the last fifth instar Loxostege sticticalis larvae undergo prepupal stage and pupate without diapause. Under a short-day photoperiod of L:D 12:12, in contrast, they all enter diapause with approximately 36 days diapause maintenance and then terminate diapause spontaneously, although only 44% of the larvae terminated diapause successfully. Changes in hemolymph juvenile hormone (JH I) titers of diapause-destined larvae across diapause induction, maintenance and termination were examined using HPLC, and were compared with those of non-diapause-destined larvae from the fifth instar through pupation. JH I titer of the earliest fifth instar diapause-destined larvae remained at a high level with a peak of 220.4 ng/ml, though it decreased continuously to a minimum of 69.0 ng/ml on day 5 in the fifth instar when the larvae stopped feeding to enter diapause. During the diapause maintenance, JH I titer of the mature larvae increased significantly and maintained a high level until day 31 in prepupae. JH I titer declined and fluctuated at low level from 5 days before pupation. In contrast, JH I titer of both the fifth instar non-diapause-destined larvae and prepupae remained and fluctuated at low level consistently, as well as decreased before pupation. These results indicate that diapause induction and maintenance in this species might be a consequence of high JH, whereas diapause termination can be attributed to low JH titer, which was in agreement with the hormonal regulation observed in many other larval-diapausing insects.     

不同温度下白蜡虫花翅跳小蜂的实验种群生命表

在15、18、21、24、27和30℃恒温下,观察了温度对白蜡虫花翅跳小蜂Microterys ericeri发育、存活和繁殖力的影响,组建了相应温度下的实验种群生命表。白蜡虫花翅跳小蜂全代的发育起点温度和有效积温分别为12.1℃和499.4日·度。27℃时发育历期最短,产卵量、产卵率和卵孵化率最高。24℃时雌虫怀卵量最多,3～5龄幼虫和蛹的存活率最高。6种温度下白蜡虫花翅跳小蜂种群的世代存活率分别为8.5%、25.2%、50.3%、68.2%、49.8%和38.1%。24℃时世代存活率、种群趋势指数、净增殖率和内禀增长力均高于其它温度处理。24℃和27℃时种群加倍时间只需12天。18℃时种群出现负增长,15℃时白蜡虫花翅跳小蜂不产卵,不能繁殖下一代。     

Effects of photoperiod and temperature on pupal diapause induction of grape berry moth Lobesia botrana

Abstract. The grape berry moth, Lobesia botrana Denn. & Sciff. (Lepidoptera: Tortricidae), one of the most injurious pest of grape berries in Greece, is a multivoltine species that overwinters as diapausing pupae. The effects of several diel and non-diel photoperiods and of temperature, experienced by eggs and larvae, on pupal diapause induction were investigated. The diapause response curve was of Type I (long day type) and the determining factor was the duration of scotophase (> 11 h), regardless of the duration of photophase. However, at very short (< 4 h) photoperiods, the incidence of diapause was also high. Diapause was positively and significantly correlated with the egg-larval developmental time, pupal mortality and the duration of the pupal stage. Eggs and larvae reared under LD 12 : 12 h photoperiod and various temperatures (from 12 to 30 °C) produced diapausing pupae (almost 100%), but the duration of the pupal stage (intensity of diapause) increased with increasing temperature. Under continuous darkness, however, the percentage diapause decreased with increasing temperature. Single and double 1-h light pulses were applied systematically at various times during the scotophase of six diapause-inducing diel photoperiods. Two photosensitive points in time (called A and B) were revealed, during which illumination resulted in a significant decrease of diapause induction. The decrease was much greater during the first sensitive period (early in scotophase) rather than in the second (late in the scotophase).     

荔枝蒂蛀虫幼虫龄数及各发育阶段在不同温度下的发育历期

【目的】荔枝蒂蛀虫 Conopomorpha sinensis Bradley是荔枝龙眼上的主要害虫,以幼虫蛀果为害。本研究旨在明确荔枝蒂蛀虫幼虫龄数及不同温度下各虫态和各龄幼虫的发育历期,为该虫发生规律、预测预报和防控技术研究提供基础生物学数据。【方法】定期收集处于不同发育时期的荔枝蒂蛀虫幼虫,测量幼虫头壳宽度,对其进行频次分析,Crosby指数验证和曲线回归分析,以确定幼虫龄数。通过室内群体饲养的方法,测定了17~38℃区间8个温度梯度下荔枝蒂蛀虫各虫态和各龄幼虫的发育历期,并采用线性日度模型对其发育速率与温度的关系进行回归分析。【结果】根据荔枝蒂蛀虫幼虫头壳宽度频次分布图,其头壳宽度的频次分布可明显分为5个区域,说明其幼虫分5个龄期,符合Dyar定律。1-5龄幼虫的头壳宽度分别为：0.092~0.120, 0.140~0.206, 0.217~0.319, 0.356~0.523和0.582~0.728 mm。温度对荔枝蒂蛀虫卵、各龄幼虫和蛹的发育历期有明显影响,其发育历期均随温度的升高而缩短,其发育速率均与温度呈显著正相关,并符合线性回归模型。在20~32℃,荔枝蒂蛀虫可完成世代发育;在17℃时,该虫只能发育至3龄幼虫;在35℃时,蛹多不能羽化;在38℃时,卵多不能孵化。在20~32℃,其世代历期为41.16~19.34 d,蛹期为12.74~5.38 d,而产卵前期为4.75~4.22 d,温度对产卵前期无明显影响。在20~35℃,荔枝蒂蛀虫幼虫可正常发育,其1龄幼虫龄期为4.50~1.17 d,2龄幼虫期为2.09~1.40 d,3龄幼虫期为2.84~1.00 d,4龄幼虫期为3.41~1.18 d,5龄幼虫期为3.00~1.37 d,预蛹期为2.41~0.69 d。在17~35℃,荔枝蒂蛀虫卵可正常孵化,其卵期为7.73~2.09 d。【结论】荔枝蒂蛀虫幼虫分5个龄期,不同于前人所报道的4个龄期。在20~32℃温度范围内,卵、各龄幼虫和蛹的发育历期均随温度升高而缩短。本研究结果有助于荔枝蒂蛀虫预测预报方案的制定和实施。