天牛(niu)是多食亞目(mu)天牛(niu)科(ke)昆蟲(chong)的總稱,咀嚼式口器,有(you)很長的觸角(jiao),常常超過身體的長度,全世界約有(you)超過20,000種。有(you)一些種類屬于(yu)害(hai)蟲(chong),其幼(you)蟲(chong)生活于(yu)木材中,可能對樹或建筑物造成(cheng)危害(hai)。
天牛是植食性(xing)昆蟲,會危害木本植物,大部分松(song)、柏、柳、榆、核桃、柑橘、蘋果(guo)、桃和(he)茶等(deng),一部分棉(mian)、麥、玉米、高(gao)粱、甘蔗(zhe)和(he)麻(ma)等(deng),少數木材(cai)、建(jian)筑、房(fang)屋和(he)家具(ju)等(deng),是林業(ye)生產、作物栽培和(he)建(jian)筑木材(cai)上的(de)主要害蟲。
鞘翅目(mu)(Coleoptera)天(tian)(tian)牛(niu)(niu)科(Cerambycidae)甲蟲,其英(ying)文(wen)俗名得自多(duo)數種的(de)(de)(de)(de)極長觸(chu)角。分布全(quan)球,但熱帶最多(duo)。長0.4~18cm,不過,若(ruo)把觸(chu)角計(ji)算在(zai)內,長度可增加2~3倍。許多(duo)成蟲(如歐洲(zhou)的(de)(de)(de)(de)蜂形虎天(tian)(tian)牛(niu)(niu)〔Clytus arietes〕)采花粉,體色黃(huang)、黑、橙相間,酷似黃(huang)蜂;有(you)些虎天(tian)(tian)牛(niu)(niu)屬(Clytus)的(de)(de)(de)(de)熱帶種類貌似蟻類;非(fei)洲(zhou)的(de)(de)(de)(de)大天(tian)(tian)牛(niu)(niu)(Pterognatha gigas)則像一塊帶有(you)幾條線(伸出(chu)的(de)(de)(de)(de)觸(chu)角)的(de)(de)(de)(de)苔蘚或地衣。
天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)的(de)(de)種(zhong)(zhong)(zhong)類很(hen)多(duo),世界已(yi)知(zhi)22000種(zhong)(zhong)(zhong),中國也(ye)(ye)有(you)(you)2200種(zhong)(zhong)(zhong)左右,分布廣泛(fan),為害(hai)普遍,幾(ji)乎每一(yi)種(zhong)(zhong)(zhong)樹(shu)(shu)木(mu),都受不同(tong)的(de)(de)天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)種(zhong)(zhong)(zhong)類所侵害(hai)。而(er)受害(hai)較(jiao)多(duo)的(de)(de)樹(shu)(shu)木(mu),像(xiang)桑樹(shu)(shu)有(you)(you)天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)28種(zhong)(zhong)(zhong),柳(liu)樹(shu)(shu)和(he)楊(yang)樹(shu)(shu)有(you)(you)25種(zhong)(zhong)(zhong),柑桔類有(you)(you)18種(zhong)(zhong)(zhong),松樹(shu)(shu)有(you)(you)23種(zhong)(zhong)(zhong)。天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)中數量多(duo)、常見(jian)的(de)(de)除(chu)星天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)和(he)桑天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)外,還有(you)(you)光肩星天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)、桃(tao)紅(hong)頸天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)、白(bai)筋(jin)天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)、紅(hong)緣天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)、云(yun)斑(ban)白(bai)條天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)、竹緣虎天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)、深(shen)山天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)等(deng)。典型的(de)(de)天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)種(zhong)(zhong)(zhong)類、身體呈長(chang)圓(yuan)筒形(xing),背部略扁,觸(chu)角(jiao)特(te)長(chang),特(te)別是比較(jiao)常見(jian)的(de)(de)幾(ji)種(zhong)(zhong)(zhong),如星天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)、桑天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)、云(yun)斑(ban)白(bai)條天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)等(deng),它們壯碩的(de)(de)軀體和(he)突出(chu)的(de)(de)兩(liang)角(jiao),使人意識到牛(niu)(niu)的(de)(de)印(yin)象(xiang)。其實天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)的(de)(de)體形(xing)大小也(ye)(ye)頗有(you)(you)變(bian)異,有(you)(you)的(de)(de)觸(chu)角(jiao)較(jiao)短(duan),有(you)(you)的(de)(de)體呈卵圓(yuan)形(xing)或(huo)其它形(xing)狀(zhuang),有(you)(you)的(de)(de)則摹擬其它昆蟲的(de)(de)形(xing)象(xiang),如薔薇天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)屬、花天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)亞科很(hen)像(xiang)蜂類。天(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)又(you)以(yi)色(se)(se)(se)彩美麗著稱,但很(hen)多(duo)種(zhong)(zhong)(zhong)類或(huo)多(duo)或(huo)少呈棕褐色(se)(se)(se),或(huo)以(yi)花斑(ban)排(pai)列,和(he)樹(shu)(shu)干的(de)(de)顏色(se)(se)(se)相橡(xiang),而(er)具有(you)(you)隱匿(ni)色(se)(se)(se)或(huo)保護色(se)(se)(se)的(de)(de)作用(yong)。
大多數天牛(niu)(niu)是大型(xing)或(huo)中型(xing)的(de)種類,體長(chang)在15~50mm之間(jian)。但亦有(you)很(hen)大的(de)如(ru)(ru)大山鋸(ju)天牛(niu)(niu),體長(chang)可達(da)110mm,較小(xiao)的(de)如(ru)(ru)微小(xiao)天牛(niu)(niu),體長(chang)僅0.5mm。同(tong)種個體之間(jian)有(you)時(shi)大小(xiao)變(bian)異也很(hen)大,如(ru)(ru)星天牛(niu)(niu)體長(chang)19~39mm,體寬6~14mm。
天牛(niu)的幼蟲以及成蟲多(duo)喜在樹(shu)木上活(huo)動,如桑樹(shu)、柳樹(shu)和楊樹(shu)、柑(gan)桔類(lei)、松樹(shu)等都有多(duo)種天牛(niu)種類(lei)在其(qi)繁衍。天牛(niu)中數量(liang)多(duo),對植被危(wei)害較大。
天(tian)(tian)牛(niu)(niu)的(de)寄主范圍(wei)在各種(zhong)類間亦有不同,很(hen)多種(zhong)類如星天(tian)(tian)牛(niu)(niu)、桑天(tian)(tian)牛(niu)(niu)、云(yun)斑天(tian)(tian)牛(niu)(niu)等(deng),其食性廣(guang)泛,能加害(hai)多種(zhong)不同科的(de)植(zhi)物;有的(de)則限于同科或接近的(de)屬,如大牙和曲牙鋸天(tian)(tian)牛(niu)(niu)為害(hai)禾本科植(zhi)物,樟紅天(tian)(tian)牛(niu)(niu)為害(hai)樟樹和楠木樹。
天(tian)牛(niu)幼蟲淡(dan)黃或(huo)白色,天(tian)牛(niu)成(cheng)蟲體呈(cheng)長圓筒(tong)形 體前(qian)端(duan)擴展成(cheng)圓形,似頭,故俗名圓頭鉆(zhan)(zhan)木蟲,上腭強壯,能鉆(zhan)(zhan)入樹內生活兩年(nian)以(yi)上,破壞木材。化(hua)蛹前(qian)向外鉆(zhan)(zhan)一(yi)孔道,在樹內化(hua)蛹,新(xin)羽化(hua)的(de)成(cheng)蟲經(jing)此孔道而出。三對(dui)足,兩對(dui)翅。由(you)于這種鉆(zhan)(zhan)木習性(xing),天(tian)牛(niu)危害木材和漿(jiang)材樹、景觀(guan)(guan)樹、果(guo)樹以(yi)及木本觀(guan)(guan)賞植物(wu)甚巨。
成蟲體(ti)(ti)(ti)呈(cheng)長(chang)圓(yuan)筒形,背(bei)部略扁(bian);觸(chu)角(jiao)著(zhu)生(sheng)(sheng)在額的(de)(de)突起(稱觸(chu)角(jiao)基瘤)上(shang),具有(you)(you)(you)使觸(chu)角(jiao)自由轉動和向后(hou)覆蓋于蟲體(ti)(ti)(ti)背(bei)上(shang)的(de)(de)功(gong)能。爪通(tong)常(chang)(chang)呈(cheng)單齒式,少數(shu)呈(cheng)附(fu)齒式。除鋸天(tian)(tian)牛(niu)(niu)(niu)類外(wai),中(zhong)(zhong)胸背(bei)板常(chang)(chang)具發(fa)(fa)(fa)音器(qi)。幼蟲體(ti)(ti)(ti)粗肥,呈(cheng)長(chang)圓(yuan)形,略扁(bian),少數(shu)體(ti)(ti)(ti)細長(chang)。頭(tou)呈(cheng)橫闊或長(chang)橢圓(yuan)形,常(chang)(chang)縮入前胸背(bei)板很深。天(tian)(tian)牛(niu)(niu)(niu)因(yin)(yin)其(qi)力(li)(li)大(da)如牛(niu)(niu)(niu),善于在天(tian)(tian)空中(zhong)(zhong)飛翔(xiang),因(yin)(yin)而得天(tian)(tian)牛(niu)(niu)(niu)之(zhi)名;又因(yin)(yin)它發(fa)(fa)(fa)出(chu)(chu)“咔嚓、咔嚓”之(zhi)聲,其(qi)聲很象是鋸樹(shu)之(zhi)聲,故(gu)又被稱作“鋸樹(shu)郎”。此外(wai),中(zhong)(zhong)國南(nan)方(fang)有(you)(you)(you)些地區稱之(zhi)為“水(shui)牯牛(niu)(niu)(niu)”、“水(shui)牛(niu)(niu)(niu)”等,北(bei)方(fang)有(you)(you)(you)些地區稱之(zhi)為“春牛(niu)(niu)(niu)兒”。此蟲因(yin)(yin)種類不同,體(ti)(ti)(ti)形的(de)(de)大(da)小(xiao)差別(bie)極(ji)大(da),最(zui)大(da)者體(ti)(ti)(ti)長(chang)可(ke)(ke)達11cm,而小(xiao)者體(ti)(ti)(ti)長(chang)僅0.4~0.5cm,此蟲特別(bie)的(de)(de)特征是其(qi)觸(chu)角(jiao)極(ji)長(chang),中(zhong)(zhong)國華北(bei)有(you)(you)(you)一種叫做(zuo)長(chang)角(jiao)灰(hui)天(tian)(tian)牛(niu)(niu)(niu)的(de)(de),其(qi)觸(chu)角(jiao)長(chang)度可(ke)(ke)達自身體(ti)(ti)(ti)長(chang)的(de)(de)4~5倍,普通(tong)所(suo)見(jian)的(de)(de)天(tian)(tian)牛(niu)(niu)(niu),其(qi)觸(chu)須亦可(ke)(ke)達10cm左(zuo)右(you)。另(ling)外(wai)一個特征就是它強有(you)(you)(you)力(li)(li)的(de)(de)下(xia)巴。天(tian)(tian)牛(niu)(niu)(niu)體(ti)(ti)(ti)色大(da)多為黑(hei)色,體(ti)(ti)(ti)上(shang)具有(you)(you)(you)金(jin)屬的(de)(de)光(guang)澤,其(qi)成蟲常(chang)(chang)見(jian)于林區、果(guo)園等處,飛行時(shi)鞘翅張開(kai)不動,由內翅扇動,發(fa)(fa)(fa)出(chu)(chu)“嚶(ying)嚶(ying)”之(zhi)聲。它多數(shu)為1年(nian)發(fa)(fa)(fa)生(sheng)(sheng)1代(dai),也(ye)有(you)(you)(you)3年(nian)2代(dai)或2年(nian)一代(dai)的(de)(de),是危害楊、柳、桑、槐、梧桐、苦楝等樹(shu)木(mu)的(de)(de)
害蟲。
鋸天(tian)(tian)牛(niu)亞(ya)(ya)科(ke):(Prioninae),鞘(qiao)翅革質,淡褐色,前胸(頭後面地區)側向擴展,緣(yuan)有齒(chi)突。該亞(ya)(ya)科(ke)的松天(tian)(tian)牛(niu)屬(Parandra,或(huo)稱異(yi)天(tian)(tian)牛(niu)屬,有時列入椎(zhui)天(tian)(tian)牛(niu)科(ke)〔Spondylidae〕)生于松樹中,闊頸鋸天(tian)(tian)牛(niu)(Prionus laticollis)的幼蟲生活(huo)在葡萄(tao)、蘋果、白楊、南(nan)方(fang)越橘和其他的果樹、觀賞樹等(deng)樹根中
花天牛(niu)亞科:(Lepturinae)。包括接骨(gu)木(mu)天牛(niu)(Desmocerus palliatus),肩部似(si)著一黃斗篷,觸角(jiao)多結(jie)節(jie),故又稱斗篷結(jie)節(jie)天牛(niu)(cloaked knotty-horn beetle)。取食接骨(gu)木(mu)的花和葉,幼蟲鉆入莖髓中。
溝脛天(tian)牛(niu)(niu)(niu)亞科:(Lamiinae),包括墨天(tian)牛(niu)(niu)(niu)屬(Monochamus)的(de)食木(mu)蟲(chong),灰(hui)棕色(se)(se),長約30公(gong)厘(li)(1.2吋(cun),不包括長觸(chu)角(jiao))。幼蟲(chong)在松、冷杉樹內鉆孔(kong)直徑(jing)(jing)達10公(gong)厘(li)(0.3吋(cun))。蘋圓(yuan)頭天(tian)牛(niu)(niu)(niu)(Saperda candida)是一(yi)種嚴(yan)重的(de)蘋果害蟲(chong)。繞枝(zhi)溝脛天(tian)牛(niu)(niu)(niu)(Oncideres cingulata,即割枝(zhi)天(tian)牛(niu)(niu)(niu))產卵(luan)在枝(zhi)條內,然後沿(yan)枝(zhi)條圓(yuan)周割一(yi)溝,後枝(zhi)條枯(ku)死并(bing)斷裂,幼蟲(chong)在枯(ku)枝(zhi)中發育(yu)。光(guang)肩(jian)(jian)(jian)星天(tian)牛(niu)(niu)(niu)(Anoplophora glabripennis),原產于中國和(he)(he)(he)朝鮮(xian),是許多硬材樹的(de)主要害蟲(chong),尤其是對(dui)楓樹、白蠟槭、七葉樹(馬栗)、鹿(lu)眼樹、柳樹和(he)(he)(he)榆樹。成(cheng)蟲(chong)亮黑色(se)(se),有不規則的(de)白點(dian),體大,長1.9~3.8cm(0.75~1.5吋(cun))。觸(chu)角(jiao)黑色(se)(se)帶有白環(huan),長3.8~10.2cm(1.5~4吋(cun))。在夏日數月中,成(cheng)年(nian)雌蟲(chong)嚼碎樹皮產卵(luan),造(zao)成(cheng)樹木(mu)一(yi)個直徑(jing)(jing)約1.3cm(0.5吋(cun))的(de)明(ming)顯(xian)深色(se)(se)傷疤(ba)。待(dai)幼蟲(chong)孵出後,移棲樹心處,在那里取食、發育(yu)成(cheng)熟,然後挖(wa)洞(dong)出來,留(liu)下9.5公(gong)厘(li)(0.375吋(cun))寬的(de)洞(dong)。據(ju)說光(guang)肩(jian)(jian)(jian)星天(tian)牛(niu)(niu)(niu)是跟著貨(huo)板運送(song)到北美,1996年(nian)使紐約蟲(chong)患成(cheng)災,幾年(nian)之(zhi)後又傳到新澤西、伊(yi)利諾(nuo)州的(de)芝加哥(ge)和(he)(he)(he)安大略省的(de)多倫(lun)多。防治(zhi)措施包括移除和(he)(he)(he)銷毀(hui)樹木(mu),隔離受(shou)傳染的(de)疫區、嚴(yan)格管控木(mu)材的(de)運送(song),并(bing)用殺蟲(chong)劑治(zhi)療(liao),把光(guang)肩(jian)(jian)(jian)星天(tian)牛(niu)(niu)(niu)限制在隔離區內。
天(tian)(tian)牛(niu)(niu)(niu)是(shi)人(ren)們(men)熟知(zhi)的(de)(de)一(yi)類(lei)昆(kun)蟲(chong)。很多人(ren)在孩童時期(qi),曾(ceng)經捕捉(zhuo)到(dao)或觀察到(dao)天(tian)(tian)牛(niu)(niu)(niu),對它(ta)們(men)發(fa)生(sheng)興趣(qu)。有(you)(you)(you)趣(qu)的(de)(de)是(shi)當(dang)你(ni)抓住它(ta)時,會發(fa)出“嘎(ga)吱(zhi)嘎(ga)吱(zhi)”聲響(xiang),企圖(tu)掙脫逃命(ming)。如若(ruo)在其(qi)腿上(shang)縛一(yi)根(gen)細線,任其(qi)飛翔,還能聽到(dao)“嚶嚶”之(zhi)聲呢。天(tian)(tian)牛(niu)(niu)(niu)的(de)(de)玩(wan)法很多,如天(tian)(tian)牛(niu)(niu)(niu)賽跑、天(tian)(tian)牛(niu)(niu)(niu)拉車、天(tian)(tian)牛(niu)(niu)(niu)釣魚(yu)(yu)(yu)、天(tian)(tian)牛(niu)(niu)(niu)賽叫(jiao)等等,比起充斥市場(chang)的(de)(de)電動(dong)(dong)玩(wan)具來,玩(wan)這(zhe)種“自然(ran)寵物(wu)”要有(you)(you)(you)趣(qu)得(de)多。不過在這(zhe)里要提醒大(da)家,在玩(wan)的(de)(de)時候,當(dang)心別被天(tian)(tian)牛(niu)(niu)(niu)強壯(zhuang)的(de)(de)上(shang)顎咬著手(shou)! 在民間(jian)流行一(yi)種“天(tian)(tian)牛(niu)(niu)(niu)釣魚(yu)(yu)(yu)”的(de)(de)游(you)戲,十(shi)分逗(dou)人(ren)開懷。方(fang)法是(shi)在一(yi)盛(sheng)水(shui)(shui)的(de)(de)盆中,置(zhi)一(yi)魚(yu)(yu)(yu)形(xing)小(xiao)(xiao)片,穿孔(kong)系線,另(ling)一(yi)頭(tou)系在天(tian)(tian)牛(niu)(niu)(niu)角上(shang),線長適(shi)度,將(jiang)天(tian)(tian)牛(niu)(niu)(niu)置(zhi)于另(ling)一(yi)小(xiao)(xiao)木條(tiao)上(shang),浮于水(shui)(shui)面(mian),天(tian)(tian)牛(niu)(niu)(niu)四周(zhou)環水(shui)(shui),局促不安,頻頻揮動(dong)(dong)觸角,形(xing)同釣魚(yu)(yu)(yu),魚(yu)(yu)(yu)若(ruo)離水(shui)(shui),則釣魚(yu)(yu)(yu)成功(gong)。如兩蟲(chong)比賽,以先釣起者(zhe)為勝,十(shi)分有(you)(you)(you)趣(qu)。天(tian)(tian)牛(niu)(niu)(niu)年(nian)齡稍大(da)些(xie)的(de)(de)有(you)(you)(you)手(shou)指那么粗,年(nian)齡小(xiao)(xiao)一(yi)些(xie)的(de)(de)差(cha)不多只有(you)(you)(you)鉛筆一(yi)般細。
天(tian)牛一(yi)般(ban)以幼(you)蟲(chong)(chong)(chong)(chong)(chong)或(huo)(huo)成(cheng)蟲(chong)(chong)(chong)(chong)(chong)在(zai)(zai)樹(shu)(shu)干(gan)內(nei)(nei)越冬(dong)。成(cheng)蟲(chong)(chong)(chong)(chong)(chong)羽化后(hou),有的(de)需進行補(bu)充營(ying)養,取(qu)食(shi)(shi)花粉、嫩(nen)枝、嫩(nen)葉、樹(shu)(shu)皮(pi)、樹(shu)(shu)汁(zhi)或(huo)(huo)果(guo)實(shi)、菌類等(deng),有的(de)不(bu)需補(bu)充營(ying)養。成(cheng)蟲(chong)(chong)(chong)(chong)(chong)壽(shou)命一(yi)般(ban)10余天(tian)至(zhi)1~2個月(yue)(yue);但在(zai)(zai)蛹(yong)室(shi)內(nei)(nei)越冬(dong)的(de)成(cheng)蟲(chong)(chong)(chong)(chong)(chong)可達7~8個月(yue)(yue),雄蟲(chong)(chong)(chong)(chong)(chong)壽(shou)命比雌蟲(chong)(chong)(chong)(chong)(chong)短。成(cheng)蟲(chong)(chong)(chong)(chong)(chong)活(huo)動(dong)時間與復(fu)眼小(xiao)(xiao)眼面(mian)粗、細(xi)(xi)有關,一(yi)般(ban)小(xiao)(xiao)眼面(mian)粗的(de),多在(zai)(zai)晚上(shang)活(huo)動(dong),有趨(qu)光性;小(xiao)(xiao)眼面(mian)細(xi)(xi)的(de),多在(zai)(zai)白天(tian)活(huo)動(dong)。成(cheng)蟲(chong)(chong)(chong)(chong)(chong)產(chan)卵(luan)方式(shi)與口(kou)器(qi)形式(shi)有關,一(yi)般(ban)前(qian)口(kou)式(shi)的(de)成(cheng)蟲(chong)(chong)(chong)(chong)(chong)產(chan)卵(luan)時將(jiang)卵(luan)直接(jie)產(chan)入(ru)粗糙樹(shu)(shu)皮(pi)或(huo)(huo)裂縫中(zhong);下(xia)口(kou)式(shi)的(de)成(cheng)蟲(chong)(chong)(chong)(chong)(chong)先在(zai)(zai)樹(shu)(shu)干(gan)上(shang)咬成(cheng)刻槽(cao),然(ran)后(hou)將(jiang)卵(luan)產(chan)在(zai)(zai)刻槽(cao)內(nei)(nei)。天(tian)牛主要(yao)以幼(you)蟲(chong)(chong)(chong)(chong)(chong)蛀(zhu)(zhu)食(shi)(shi),生活(huo)時間長(chang),對樹(shu)(shu)干(gan)危(wei)害嚴重(zhong)。當(dang)卵(luan)孵(fu)化出幼(you)蟲(chong)(chong)(chong)(chong)(chong)后(hou),初(chu)齡幼(you)蟲(chong)(chong)(chong)(chong)(chong)即蛀(zhu)(zhu)入(ru)樹(shu)(shu)干(gan),最初(chu)在(zai)(zai)樹(shu)(shu)皮(pi)下(xia)取(qu)食(shi)(shi),待齡期(qi)增大后(hou),即鉆入(ru)木質(zhi)部為害,有的(de)種(zhong)類僅(jin)停留(liu)在(zai)(zai)樹(shu)(shu)皮(pi)下(xia)生活(huo),不(bu)蛀(zhu)(zhu)入(ru)木質(zhi)部。幼(you)蟲(chong)(chong)(chong)(chong)(chong)在(zai)(zai)樹(shu)(shu)干(gan)內(nei)(nei)活(huo)動(dong),蛀(zhu)(zhu)食(shi)(shi)隧道的(de)形狀和(he)長(chang)短隨種(zhong)類而(er)異。幼(you)蟲(chong)(chong)(chong)(chong)(chong)在(zai)(zai)樹(shu)(shu)干(gan)或(huo)(huo)枝條(tiao)上(shang)蛀(zhu)(zhu)食(shi)(shi),在(zai)(zai)一(yi)定(ding)距離內(nei)(nei)向樹(shu)(shu)皮(pi)上(shang)開口(kou)作為通氣孔,向外(wai)推出排(pai)泄物和(he)木屑(xie)。幼(you)蟲(chong)(chong)(chong)(chong)(chong)老熟(shu)后(hou)即筑成(cheng)較寬的(de)蛹(yong)室(shi),兩端以纖維和(he)木屑(xie)堵塞,而(er)在(zai)(zai)其中(zhong)化蛹(yong)。蛹(yong)期(qi)約10~20多天(tian)。
天牛(niu)(niu)的(de)幼蟲蛀食樹(shu)干和樹(shu)枝(zhi),影響樹(shu)木的(de)生長發育,使樹(shu)勢衰弱,導致(zhi)病菌侵入,也(ye)易(yi)被(bei)風折(zhe)斷。受害嚴重(zhong)時,整株死亡,木材被(bei)蛀,失(shi)去工藝價值。天牛(niu)(niu)主要是木本植物(wu)的(de)害蟲,在幼蟲期蛀蝕樹(shu)干、枝(zhi)條及(ji)根部(bu)。有一部(bu)分(fen)為害草本植物(wu),幼蟲生活(huo)于莖或根內(nei),如菊天牛(niu)(niu)、瓜藤天牛(niu)(niu)等。個別種類(lei)如棉蒴天牛(niu)(niu),則為害棉蒴。還有少數種類(lei),幼蟲不生活(huo)在植物(wu)組織內(nei),而是在土壤中取食根部(bu),如大(da)牙(ya)及(ji)曲牙(ya)鋸(ju)天牛(niu)(niu)、草天牛(niu)(niu)等等。
關于成蟲(chong)的食(shi)性(xing)(xing)(xing),已知有(you)(you)取食(shi)花粉、嫩(nen)樹皮、嫩(nen)枝(zhi)、葉(xie)、根、樹汁、果實、菌類(lei)等不同習(xi)性(xing)(xing)(xing)。一般說來,花天牛類(lei)常以(yi)花粉為食(shi)。溝脛天牛類(lei)常食(shi)害嫩(nen)樹皮、嫩(nen)枝(zhi)和(he)葉(xie)。其它亞科的成蟲(chong)亦(yi)有(you)(you)取食(shi)的,亦(yi)有(you)(you)一部分(fen)可能并不取食(shi)。在同一亞科內食(shi)性(xing)(xing)(xing)的變(bian)異亦(yi)很大。
天(tian)(tian)牛(niu)(niu)生(sheng)(sheng)(sheng)活(huo)(huo)史的(de)(de)(de)(de)(de)(de)(de)長(chang)短依種(zhong)類(lei)而(er)異,有一(yi)(yi)(yi)年(nian)(nian)(nian)完成(cheng)(cheng)(cheng)1代(dai)或(huo)2代(dai)的(de)(de)(de)(de)(de)(de)(de),也(ye)有二(er)、三(san)年(nian)(nian)(nian)甚(shen)至四(si)、五年(nian)(nian)(nian)完成(cheng)(cheng)(cheng)1代(dai)的(de)(de)(de)(de)(de)(de)(de)。同一(yi)(yi)(yi)種(zhong)類(lei)在(zai)不(bu)(bu)同地域(yu)的(de)(de)(de)(de)(de)(de)(de)生(sheng)(sheng)(sheng)活(huo)(huo)史有時(shi)亦很(hen)(hen)不(bu)(bu)同,如(ru)黃星桑天(tian)(tian)牛(niu)(niu)在(zai)江(jiang)蘇需(xu)三(san)年(nian)(nian)(nian)完成(cheng)(cheng)(cheng)一(yi)(yi)(yi)世(shi)代(dai),而(er)在(zai)廣東(dong)則一(yi)(yi)(yi)年(nian)(nian)(nian)發生(sheng)(sheng)(sheng)兩(liang)代(dai)。由于幼蟲(chong)(chong)(chong)的(de)(de)(de)(de)(de)(de)(de)隱藏生(sheng)(sheng)(sheng)活(huo)(huo),對(dui)它們進生(sheng)(sheng)(sheng)活(huo)(huo)史觀察(cha)很(hen)(hen)有困難。又由于寄主植物的(de)(de)(de)(de)(de)(de)(de)條件如(ru)老(lao)幼、健康(kang)、干濕程(cheng)度等,對(dui)幼蟲(chong)(chong)(chong)的(de)(de)(de)(de)(de)(de)(de)長(chang)發育(yu)影(ying)響很(hen)(hen)大(da)。不(bu)(bu)良條件常引起(qi)幼蟲(chong)(chong)(chong)的(de)(de)(de)(de)(de)(de)(de)滯育(yu)而(er)使生(sheng)(sheng)(sheng)活(huo)(huo)世(shi)代(dai)大(da)大(da)地延(yan)長(chang)。所以(yi)(yi)同-種(zhong)類(lei)在(zai)同一(yi)(yi)(yi)地區內(nei)可(ke)(ke)能呈現不(bu)(bu)同的(de)(de)(de)(de)(de)(de)(de)發育(yu)過程(cheng)。文獻(xian)上有許(xu)多(duo)關(guan)于長(chang)壽(shou)幼蟲(chong)(chong)(chong)的(de)(de)(de)(de)(de)(de)(de)記,這(zhe)些大(da)都(dou)是(shi)根據木材制成(cheng)(cheng)(cheng)了家具后,經(jing)過若干年(nian)(nian)(nian)代(dai),忽然發現其中尚有生(sheng)(sheng)(sheng)存的(de)(de)(de)(de)(de)(de)(de)天(tian)(tian)幼蟲(chong)(chong)(chong),或(huo)者天(tian)(tian)牛(niu)(niu)忽然羽化而(er)此證明它在(zai)木器內(nei)已(yi)生(sheng)(sheng)(sheng)活(huo)(huo)了很(hen)(hen)多(duo)年(nian)(nian)(nian)代(dai)。已(yi)有很(hen)(hen)多(duo)這(zhe)樣的(de)(de)(de)(de)(de)(de)(de)例子,證明天(tian)(tian)牛(niu)(niu)幼蟲(chong)(chong)(chong)可(ke)(ke)以(yi)(yi)生(sheng)(sheng)(sheng)活(huo)(huo)到(dao)一(yi)(yi)(yi)、二(er)十年(nian)(nian)(nian),而(er)最高的(de)(de)(de)(de)(de)(de)(de)2個(ge)(ge)記錄是(shi)40年(nian)(nian)(nian)和45年(nian)(nian)(nian)。天(tian)(tian)牛(niu)(niu)一(yi)(yi)(yi)般(ban)(ban)以(yi)(yi)幼蟲(chong)(chong)(chong)越冬(dong)(dong),或(huo)以(yi)(yi)成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong)在(zai)蛹室(shi)內(nei)越冬(dong)(dong),即上一(yi)(yi)(yi)年(nian)(nian)(nian)秋冬(dong)(dong)之際羽化的(de)(de)(de)(de)(de)(de)(de)成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong),留在(zai)蛹室(shi)內(nei)到(dao)翌年(nian)(nian)(nian)春夏間(jian)才(cai)出來。成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong)的(de)(de)(de)(de)(de)(de)(de)壽(shou)命一(yi)(yi)(yi)般(ban)(ban)不(bu)(bu)長(chang),十數天(tian)(tian)到(dao)一(yi)(yi)(yi)、二(er)個(ge)(ge)月,但在(zai)蛹室(shi)內(nei)越冬(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong)可(ke)(ke)能達到(dao)七(qi)、八個(ge)(ge)月。雄蟲(chong)(chong)(chong)壽(shou)命一(yi)(yi)(yi)般(ban)(ban)較(jiao)雌蟲(chong)(chong)(chong)為(wei)短。成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong)活(huo)(huo)動(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)時(shi)間(jian)在(zai)各種(zhong)類(lei)間(jian)也(ye)各有不(bu)(bu)同,有的(de)(de)(de)(de)(de)(de)(de)在(zai)白天(tian)(tian)日光下活(huo)(huo)動(dong)(dong),活(huo)(huo)躍的(de)(de)(de)(de)(de)(de)(de)是(shi)花天(tian)(tian)牛(niu)(niu)類(lei);有的(de)(de)(de)(de)(de)(de)(de)則在(zai)夜(ye)晚(wan)(wan)或(huo)陰天(tian)(tian)活(huo)(huo)動(dong)(dong),或(huo)整晚(wan)(wan)都(dou)能活(huo)(huo)動(dong)(dong)。
產(chan)卵(luan)(luan)(luan)方式(shi):主要(yao)有(you)兩(liang)種,一種是(shi)雌蟲在(zai)(zai)產(chan)前先(xian)用上顎咬(yao)破樹皮(pi)(特別是(shi)溝(gou)脛(jing)天牛(niu)), 然后(hou)用產(chan)卵(luan)(luan)(luan)管插入,每孔(kong)產(chan)卵(luan)(luan)(luan)一粒,也有(you)產(chan)多粒的(de)(de)。這樣形成的(de)(de)產(chan)卵(luan)(luan)(luan)孔(kong),其形狀(zhuang)大小在(zai)(zai)各種類(lei)間常有(you)不(bu)同(tong),有(you)的(de)(de)很顯著(zhu),在(zai)(zai)防治上可作搜滅蟲卵(luan)(luan)(luan)的(de)(de)指示。另一種產(chan)卵(luan)(luan)(luan)方式(shi)不(bu)先(xian)咬(yao)孔(kong),而(er)是(shi)直接用產(chan)卵(luan)(luan)(luan)管在(zai)(zai)樹皮(pi)縫隙內產(chan)卵(luan)(luan)(luan)。在(zai)(zai)少數情(qing)況下(xia),也有(you)產(chan)在(zai)(zai)枝干光滑部(bu)分(fen)的(de)(de)。士居種類(lei)產(chan)卵(luan)(luan)(luan)于土壤內。
初(chu)孵的(de)(de)(de)(de)幼(you)(you)蟲(chong)(chong)一般(ban)先在(zai)皮下蛀食,經過或(huo)(huo)長或(huo)(huo)短的(de)(de)(de)(de)時(shi)期后才深入(ru)到木質部分。少數種類(lei)僅在(zai)皮下蛀蝕(shi)。也(ye)有(you)的(de)(de)(de)(de)種類(lei)則穿鑿不(bu)深,僅在(zai)邊材部為害。許(xu)多(duo)種類(lei)侵害基干(gan)或(huo)(huo)粗枝(zhi),有(you)的(de)(de)(de)(de)在(zai)根(gen)干(gan),有(you)的(de)(de)(de)(de)則在(zai)枝(zhi)條蛀蝕(shi)。幼(you)(you)蟲(chong)(chong)蛀蝕(shi)時(shi)穿鑿各種坑道(dao)(dao),或(huo)(huo)上或(huo)(huo)下,或(huo)(huo)左或(huo)(huo)右,或(huo)(huo)彎或(huo)(huo)直,隨種類(lei)而異,但也(ye)有(you)許(xu)多(duo)種類(lei)的(de)(de)(de)(de)坑道(dao)(dao)很不(bu)規(gui)則。在(zai)坑道(dao)(dao)內常(chang)充滿(man)蟲(chong)(chong)糞及纖(xian)維(wei)質木屑.有(you)時(shi)蟲(chong)(chong)糞木屑由蟲(chong)(chong)孔向外排(pai)出(chu),有(you)時(shi)受害處并有(you)樹汁流出(chu)。老熟幼(you)(you)蟲(chong)(chong)常(chang)筑(zhu)成較寬(kuan)的(de)(de)(de)(de)坑道(dao)(dao)作為蛹(yong)室(shi),兩(liang)端以纖(xian)維(wei)木屑封閉(bi),在(zai)其中化蛹(yong)。