幼虫取食不同寄主树种的云斑白条天牛成虫种群分化

Population Differentation of Batocera lineolata(Coleoptera:Cerambycidae)Adults Whose Larvae Fed on Different Host Tree Species

【目的】基于幼虫取食不同寄主树种云斑白条天牛的成虫补充营养行为、形态特征及遗传特性的比较,探讨不同寄主对成虫行为的影响及其机制。【方法】比较幼虫取食毛白杨和美国红木岑2种寄主树种的云斑白条天牛成虫外形特征及雄性生殖器结构差异,利用选择性取食试验,观测这2类云斑白条天牛成虫对美国红木岑、野蔷薇、美国山核桃、日本珊瑚树及毛白杨5种寄主植物嫩枝的取食行为及交配行为,最后基于COI基因分析二者间遗传多样性差异及系统发育关系。【结果】1)幼虫取食美国红木岑的云斑白条天牛和幼虫取食毛白杨的云斑白条天牛外部特征存在明显差异。幼虫取食美国红木岑的云斑白条天牛雄虫腹部末端窄,呈钝角内凹状,毛稀疏,雌虫腹部末端呈弧形内凹,底部中央缺刻不明显,而幼虫取食毛白杨的云斑白条天牛雄虫腹部末端宽,呈弧形内凹状,密被毛,雌虫腹部末端呈平截状,底部中央具有明显缺刻;两者生殖器差异不明显;2)幼虫取食美国红木岑的云斑白条天牛成虫仅取食美国红木岑嫩枝,而幼虫取食毛白杨的云斑白条天牛可取食野蔷薇、美国山核桃和日本珊瑚树3种植物嫩枝,偏好顺序为野蔷薇>美国山核桃>日本珊瑚树;3)2个种群的天牛雌、雄成虫之间可相互交配,平均交配次数较同类群间存在差异但不显著(P>0.05);4)2个不同寄主源的天牛种群存在明显遗传分化,分化指数Fst=0.814(P<0.001),变异分化主要来源于种群间(83.19%)。【结论】幼虫的取食经历(取食不同寄主植物)和生境异质性可能对云斑白条天牛成虫补充营养行为及种群遗传分化产生显著影响。

【Objective】The effects of different host tree species,on which Batocera lineolata larvae fed,on adult behavior and the internal mechanism were discussed based on the comparisons of the supplementary nutritional behavior,morphological characteristics and genetic traits of B.lineolata adults.【Method】B.lineolata adults emerged from host trees of Populus tomentosa and Fraxinus pennsylvanica were collected respectively.The external morphology and male genital structure of B.lineolata adults from the two host plants were observed and compared.Then,through the feeding preference experiment,the feeding behavior and mating behavior of these two kinds of adults on the shoots of five plant species,i.e.Rosa multiflora,Carya illinoinensis,Viburnum odoratissimum var.awabuki,F.pennsylvanica and P.tomentosa were observed.The interactive mating tests were conducted between B.lineolata adults from the two host plants.Finally,mitochondrial cytochrome c oxidase subunit I(COI)gene sequences of the two populations of B.lineolata were cloned by universal primer,and the sequence differences and phylogenetic relationships were analyzed based on COI gene.【Result】1)There are obvious differences in external morphology between the two B.lineolata beetles whose larvae fed on P.tomentosa and F.pennsylvanica,respectively.The bottom of abdomen of the male adults emerged from F.pennsylvanica is narrow,in obtuse angle,inward-concave and covered with sparse hairs,and the bottom of the female adults is curved-concave,and the central indentation of the bottom is not obvious.However,the bottom of abdomen of the male adult from P.tomentosa is wide,curved,inner-concave and covered with dense hairs.And the bottom of the female adults is flattened and the central indentation of the bottom is obvious.The genital morphological characteristics of the two beetles are similar.2)B.lineolata adults from F.pennsylvanica only consumed the fresh branches of F.pennsylvanica,and B.lineolata from P.tomentosa fed on three plant species,and preferred order was R.multiflora>C.illinoinensis>V.odoratissimum var.awabuki;3)Male and female adults from different host plants were able to mate with each other,and the mean mating bouts was equal to that of male and female adults from the same host plant(P>0.05);4)Analysis of molecular variation(AMOVA)for COI genes indicated a significant genetic differentiation between the two B.lineolata populations(Fst=0.81385,P<0.001),and most of the genetic variance was among populations(81.39%)rather than within populations(18.61%).【Conclusion】Larval feeding experience(feeding on different host plants)and habit differentiation can significantly affect feeding behavior of B.lineolata adults and genetic variation of populations.