天(tian)牛是多食亞目(mu)天(tian)牛科昆蟲的總稱(cheng),咀嚼式口器,有很長的觸角,常常超過(guo)身體(ti)的長度(du),全世界約(yue)有超過(guo)20,000種。有一些種類屬于害蟲,其幼蟲生活于木材中,可能對樹或建筑物造成(cheng)危害。
天牛是(shi)植食(shi)性昆蟲,會危害木本植物,大部(bu)分松、柏、柳、榆、核桃(tao)、柑橘(ju)、蘋果(guo)、桃(tao)和茶等,一部(bu)分棉(mian)、麥、玉米、高(gao)粱、甘蔗和麻(ma)等,少(shao)數木材、建筑、房屋和家具等,是(shi)林業生產(chan)、作物栽培(pei)和建筑木材上(shang)的主(zhu)要害蟲。
鞘翅目(mu)(Coleoptera)天(tian)(tian)(tian)牛科(Cerambycidae)甲(jia)蟲(chong),其英文俗名得自多(duo)數(shu)種(zhong)的(de)極長觸角。分布全球,但熱帶(dai)最多(duo)。長0.4~18cm,不過,若(ruo)把觸角計算在內,長度(du)可增加2~3倍。許(xu)多(duo)成(cheng)蟲(chong)(如歐(ou)洲的(de)蜂形虎天(tian)(tian)(tian)牛〔Clytus arietes〕)采花粉,體(ti)色(se)黃(huang)(huang)、黑(hei)、橙相(xiang)間,酷似黃(huang)(huang)蜂;有些虎天(tian)(tian)(tian)牛屬(Clytus)的(de)熱帶(dai)種(zhong)類貌(mao)似蟻類;非洲的(de)大天(tian)(tian)(tian)牛(Pterognatha gigas)則像一塊帶(dai)有幾(ji)條(tiao)線(xian)(伸出的(de)觸角)的(de)苔蘚或(huo)地衣。
天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)的(de)(de)(de)種(zhong)(zhong)(zhong)類(lei)很多(duo),世界已知22000種(zhong)(zhong)(zhong),中國也有(you)(you)(you)2200種(zhong)(zhong)(zhong)左右,分布廣(guang)泛(fan),為(wei)害普遍,幾(ji)乎每一種(zhong)(zhong)(zhong)樹木,都受不同的(de)(de)(de)天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)種(zhong)(zhong)(zhong)類(lei)所侵害。而受害較多(duo)的(de)(de)(de)樹木,像桑(sang)(sang)樹有(you)(you)(you)天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)28種(zhong)(zhong)(zhong),柳樹和(he)(he)楊樹有(you)(you)(you)25種(zhong)(zhong)(zhong),柑桔類(lei)有(you)(you)(you)18種(zhong)(zhong)(zhong),松(song)樹有(you)(you)(you)23種(zhong)(zhong)(zhong)。天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)中數量多(duo)、常見(jian)的(de)(de)(de)除星天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)和(he)(he)桑(sang)(sang)天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)外,還有(you)(you)(you)光(guang)肩星天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)、桃(tao)紅頸天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)、白(bai)筋天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)、紅緣(yuan)天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)、云(yun)斑白(bai)條(tiao)(tiao)天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)、竹緣(yuan)虎天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)、深山(shan)天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)等。典型(xing)的(de)(de)(de)天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)種(zhong)(zhong)(zhong)類(lei)、身體(ti)(ti)(ti)呈長圓(yuan)筒形,背部(bu)略扁,觸(chu)(chu)角(jiao)(jiao)特長,特別是比(bi)較常見(jian)的(de)(de)(de)幾(ji)種(zhong)(zhong)(zhong),如(ru)星天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)、桑(sang)(sang)天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)、云(yun)斑白(bai)條(tiao)(tiao)天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)等,它們壯碩的(de)(de)(de)軀(qu)體(ti)(ti)(ti)和(he)(he)突出的(de)(de)(de)兩角(jiao)(jiao),使人意識到牛(niu)(niu)(niu)的(de)(de)(de)印象。其實天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)的(de)(de)(de)體(ti)(ti)(ti)形大小也頗(po)有(you)(you)(you)變異,有(you)(you)(you)的(de)(de)(de)觸(chu)(chu)角(jiao)(jiao)較短(duan),有(you)(you)(you)的(de)(de)(de)體(ti)(ti)(ti)呈卵圓(yuan)形或其它形狀(zhuang),有(you)(you)(you)的(de)(de)(de)則摹擬(ni)其它昆蟲的(de)(de)(de)形象,如(ru)薔(qiang)薇天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)屬、花天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)亞科很像蜂類(lei)。天(tian)(tian)(tian)(tian)(tian)(tian)(tian)牛(niu)(niu)(niu)又(you)以色(se)彩美(mei)麗著稱,但很多(duo)種(zhong)(zhong)(zhong)類(lei)或多(duo)或少呈棕褐色(se),或以花斑排(pai)列,和(he)(he)樹干的(de)(de)(de)顏色(se)相橡,而具有(you)(you)(you)隱(yin)匿色(se)或保護色(se)的(de)(de)(de)作用。
大(da)(da)多數(shu)天(tian)牛是大(da)(da)型或中型的種(zhong)類,體長(chang)在15~50mm之間。但亦(yi)有很(hen)大(da)(da)的如(ru)大(da)(da)山鋸天(tian)牛,體長(chang)可達(da)110mm,較小的如(ru)微小天(tian)牛,體長(chang)僅(jin)0.5mm。同種(zhong)個體之間有時大(da)(da)小變(bian)異也很(hen)大(da)(da),如(ru)星天(tian)牛體長(chang)19~39mm,體寬6~14mm。
天牛的(de)幼蟲以及成蟲多喜在(zai)樹木上活動,如桑樹、柳樹和楊樹、柑桔(jie)類、松樹等都有多種天牛種類在(zai)其繁衍。天牛中數(shu)量多,對植被危害較大。
天(tian)(tian)(tian)牛(niu)(niu)(niu)的寄主范圍(wei)在各種類間亦(yi)有不(bu)同(tong),很(hen)多(duo)種類如星天(tian)(tian)(tian)牛(niu)(niu)(niu)、桑天(tian)(tian)(tian)牛(niu)(niu)(niu)、云斑(ban)天(tian)(tian)(tian)牛(niu)(niu)(niu)等,其食性廣泛,能加害多(duo)種不(bu)同(tong)科(ke)的植物(wu);有的則限于同(tong)科(ke)或接近的屬(shu),如大牙和曲牙鋸天(tian)(tian)(tian)牛(niu)(niu)(niu)為害禾本科(ke)植物(wu),樟(zhang)紅(hong)天(tian)(tian)(tian)牛(niu)(niu)(niu)為害樟(zhang)樹和楠木樹。
天牛幼蟲(chong)(chong)淡(dan)黃或白色,天牛成蟲(chong)(chong)體(ti)呈長圓(yuan)(yuan)筒(tong)形(xing) 體(ti)前(qian)端(duan)擴展成圓(yuan)(yuan)形(xing),似頭,故(gu)俗名(ming)圓(yuan)(yuan)頭鉆木(mu)(mu)蟲(chong)(chong),上腭(e)強壯,能鉆入樹內生活兩年以上,破壞木(mu)(mu)材(cai)。化(hua)蛹(yong)前(qian)向(xiang)外鉆一(yi)孔(kong)道(dao),在樹內化(hua)蛹(yong),新羽(yu)化(hua)的成蟲(chong)(chong)經此孔(kong)道(dao)而出。三對足,兩對翅。由于(yu)這種鉆木(mu)(mu)習(xi)性,天牛危害木(mu)(mu)材(cai)和漿材(cai)樹、景觀(guan)樹、果樹以及木(mu)(mu)本觀(guan)賞(shang)植(zhi)物甚巨。
成(cheng)蟲體(ti)(ti)呈長(chang)(chang)圓(yuan)筒形(xing),背部略扁;觸(chu)角著生(sheng)在(zai)額(e)的(de)(de)(de)突起(qi)(稱(cheng)(cheng)觸(chu)角基(ji)瘤)上,具有(you)使觸(chu)角自由轉動(dong)和向(xiang)后覆蓋于蟲體(ti)(ti)背上的(de)(de)(de)功能。爪(zhua)通(tong)常(chang)(chang)呈單齒式,少數(shu)呈附(fu)齒式。除鋸(ju)天(tian)牛(niu)(niu)類外(wai)(wai),中胸(xiong)背板常(chang)(chang)具發音器。幼蟲體(ti)(ti)粗肥,呈長(chang)(chang)圓(yuan)形(xing),略扁,少數(shu)體(ti)(ti)細長(chang)(chang)。頭呈橫(heng)闊(kuo)或(huo)長(chang)(chang)橢圓(yuan)形(xing),常(chang)(chang)縮入(ru)前(qian)胸(xiong)背板很(hen)深。天(tian)牛(niu)(niu)因(yin)(yin)其(qi)(qi)力大如牛(niu)(niu),善(shan)于在(zai)天(tian)空中飛翔,因(yin)(yin)而得天(tian)牛(niu)(niu)之(zhi)(zhi)名;又因(yin)(yin)它發出“咔(ka)嚓、咔(ka)嚓”之(zhi)(zhi)聲,其(qi)(qi)聲很(hen)象是鋸(ju)樹之(zhi)(zhi)聲,故又被稱(cheng)(cheng)作“鋸(ju)樹郎”。此(ci)外(wai)(wai),中國南方有(you)些地(di)區(qu)稱(cheng)(cheng)之(zhi)(zhi)為(wei)“水牯牛(niu)(niu)”、“水牛(niu)(niu)”等(deng)(deng),北方有(you)些地(di)區(qu)稱(cheng)(cheng)之(zhi)(zhi)為(wei)“春牛(niu)(niu)兒”。此(ci)蟲因(yin)(yin)種(zhong)類不同,體(ti)(ti)形(xing)的(de)(de)(de)大小(xiao)差別極大,最(zui)大者體(ti)(ti)長(chang)(chang)可達11cm,而小(xiao)者體(ti)(ti)長(chang)(chang)僅(jin)0.4~0.5cm,此(ci)蟲特(te)別的(de)(de)(de)特(te)征(zheng)(zheng)是其(qi)(qi)觸(chu)角極長(chang)(chang),中國華北有(you)一(yi)種(zhong)叫做長(chang)(chang)角灰天(tian)牛(niu)(niu)的(de)(de)(de),其(qi)(qi)觸(chu)角長(chang)(chang)度(du)可達自身體(ti)(ti)長(chang)(chang)的(de)(de)(de)4~5倍,普通(tong)所(suo)見的(de)(de)(de)天(tian)牛(niu)(niu),其(qi)(qi)觸(chu)須(xu)亦可達10cm左右。另外(wai)(wai)一(yi)個特(te)征(zheng)(zheng)就是它強(qiang)有(you)力的(de)(de)(de)下巴。天(tian)牛(niu)(niu)體(ti)(ti)色(se)大多(duo)為(wei)黑色(se),體(ti)(ti)上具有(you)金(jin)屬的(de)(de)(de)光澤,其(qi)(qi)成(cheng)蟲常(chang)(chang)見于林區(qu)、果(guo)園等(deng)(deng)處,飛行時鞘(qiao)翅張開不動(dong),由內翅扇動(dong),發出“嚶嚶”之(zhi)(zhi)聲。它多(duo)數(shu)為(wei)1年(nian)(nian)(nian)發生(sheng)1代(dai),也有(you)3年(nian)(nian)(nian)2代(dai)或(huo)2年(nian)(nian)(nian)一(yi)代(dai)的(de)(de)(de),是危害楊(yang)、柳(liu)、桑、槐、梧桐、苦楝等(deng)(deng)樹木(mu)的(de)(de)(de)
害蟲。
鋸(ju)天牛(niu)亞科:(Prioninae),鞘翅革質,淡褐色,前胸(頭後面地區(qu))側向擴展,緣有齒突(tu)。該(gai)亞科的松(song)天牛(niu)屬(Parandra,或稱異天牛(niu)屬,有時列入椎(zhui)天牛(niu)科〔Spondylidae〕)生(sheng)于松(song)樹(shu)中(zhong),闊頸鋸(ju)天牛(niu)(Prionus laticollis)的幼蟲生(sheng)活(huo)在葡萄、蘋果、白楊、南方越橘和(he)其他(ta)的果樹(shu)、觀賞樹(shu)等樹(shu)根中(zhong)
花天牛(niu)亞科:(Lepturinae)。包(bao)括接骨木天牛(niu)(Desmocerus palliatus),肩(jian)部似著(zhu)一黃(huang)斗篷,觸角多結(jie)節,故又稱斗篷結(jie)節天牛(niu)(cloaked knotty-horn beetle)。取食接骨木的花和葉,幼蟲鉆(zhan)入莖髓中。
溝(gou)脛(jing)天(tian)牛(niu)(niu)(niu)亞科:(Lamiinae),包(bao)括墨(mo)天(tian)牛(niu)(niu)(niu)屬(Monochamus)的(de)(de)食木蟲(chong)(chong),灰棕色(se),長約30公厘(li)(li)(1.2吋(cun)(cun),不包(bao)括長觸(chu)角)。幼蟲(chong)(chong)在(zai)(zai)松(song)、冷杉樹(shu)(shu)內(nei)鉆孔直徑達10公厘(li)(li)(0.3吋(cun)(cun))。蘋圓(yuan)頭天(tian)牛(niu)(niu)(niu)(Saperda candida)是一(yi)種嚴重的(de)(de)蘋果害(hai)蟲(chong)(chong)。繞枝(zhi)溝(gou)脛(jing)天(tian)牛(niu)(niu)(niu)(Oncideres cingulata,即(ji)割枝(zhi)天(tian)牛(niu)(niu)(niu))產(chan)卵在(zai)(zai)枝(zhi)條(tiao)內(nei),然(ran)後沿枝(zhi)條(tiao)圓(yuan)周割一(yi)溝(gou),後枝(zhi)條(tiao)枯死并斷裂,幼蟲(chong)(chong)在(zai)(zai)枯枝(zhi)中發育。光肩星天(tian)牛(niu)(niu)(niu)(Anoplophora glabripennis),原產(chan)于中國和朝鮮,是許多硬材(cai)樹(shu)(shu)的(de)(de)主(zhu)要害(hai)蟲(chong)(chong),尤其是對楓樹(shu)(shu)、白(bai)蠟槭(qi)、七葉(xie)樹(shu)(shu)(馬栗)、鹿眼樹(shu)(shu)、柳樹(shu)(shu)和榆(yu)樹(shu)(shu)。成蟲(chong)(chong)亮黑色(se),有(you)不規則的(de)(de)白(bai)點,體(ti)大,長1.9~3.8cm(0.75~1.5吋(cun)(cun))。觸(chu)角黑色(se)帶有(you)白(bai)環,長3.8~10.2cm(1.5~4吋(cun)(cun))。在(zai)(zai)夏日數月中,成年雌蟲(chong)(chong)嚼碎樹(shu)(shu)皮產(chan)卵,造成樹(shu)(shu)木一(yi)個直徑約1.3cm(0.5吋(cun)(cun))的(de)(de)明顯深色(se)傷疤。待幼蟲(chong)(chong)孵(fu)出後,移(yi)(yi)棲樹(shu)(shu)心處,在(zai)(zai)那里取食、發育成熟,然(ran)後挖洞(dong)出來,留下9.5公厘(li)(li)(0.375吋(cun)(cun))寬的(de)(de)洞(dong)。據說光肩星天(tian)牛(niu)(niu)(niu)是跟著貨板運(yun)送(song)到(dao)北美,1996年使紐(niu)約蟲(chong)(chong)患成災,幾(ji)年之後又傳到(dao)新澤(ze)西、伊(yi)利諾州(zhou)的(de)(de)芝(zhi)加哥和安大略省的(de)(de)多倫多。防治措施包(bao)括移(yi)(yi)除和銷毀樹(shu)(shu)木,隔(ge)離(li)受(shou)傳染的(de)(de)疫(yi)區(qu)、嚴格管(guan)控木材(cai)的(de)(de)運(yun)送(song),并用殺蟲(chong)(chong)劑治療,把(ba)光肩星天(tian)牛(niu)(niu)(niu)限制在(zai)(zai)隔(ge)離(li)區(qu)內(nei)。
天(tian)(tian)牛(niu)是人們熟(shu)知的(de)一(yi)(yi)(yi)(yi)(yi)(yi)類昆蟲。很多(duo)(duo)(duo)人在(zai)孩(hai)童(tong)時(shi)期,曾經捕捉到或觀察到天(tian)(tian)牛(niu),對它(ta)們發(fa)(fa)生興(xing)趣(qu)。有趣(qu)的(de)是當你抓住它(ta)時(shi),會發(fa)(fa)出“嘎吱嘎吱”聲響,企圖掙脫逃命(ming)。如(ru)(ru)若在(zai)其腿上(shang)(shang)縛(fu)一(yi)(yi)(yi)(yi)(yi)(yi)根細(xi)線(xian),任其飛翔,還能聽到“嚶嚶”之聲呢(ni)。天(tian)(tian)牛(niu)的(de)玩法很多(duo)(duo)(duo),如(ru)(ru)天(tian)(tian)牛(niu)賽(sai)(sai)(sai)跑、天(tian)(tian)牛(niu)拉車、天(tian)(tian)牛(niu)釣(diao)魚(yu)(yu)、天(tian)(tian)牛(niu)賽(sai)(sai)(sai)叫等等,比起(qi)充斥市場(chang)的(de)電動(dong)玩具(ju)來,玩這(zhe)種“自然(ran)寵(chong)物”要有趣(qu)得多(duo)(duo)(duo)。不(bu)過在(zai)這(zhe)里要提醒大家(jia),在(zai)玩的(de)時(shi)候,當心(xin)別被天(tian)(tian)牛(niu)強(qiang)壯的(de)上(shang)(shang)顎(e)咬著(zhu)手! 在(zai)民間(jian)流行一(yi)(yi)(yi)(yi)(yi)(yi)種“天(tian)(tian)牛(niu)釣(diao)魚(yu)(yu)”的(de)游戲,十分(fen)逗人開(kai)懷。方法是在(zai)一(yi)(yi)(yi)(yi)(yi)(yi)盛水(shui)(shui)的(de)盆中(zhong),置(zhi)一(yi)(yi)(yi)(yi)(yi)(yi)魚(yu)(yu)形小片,穿孔系(xi)線(xian),另(ling)一(yi)(yi)(yi)(yi)(yi)(yi)頭系(xi)在(zai)天(tian)(tian)牛(niu)角上(shang)(shang),線(xian)長適度,將天(tian)(tian)牛(niu)置(zhi)于(yu)另(ling)一(yi)(yi)(yi)(yi)(yi)(yi)小木條上(shang)(shang),浮(fu)于(yu)水(shui)(shui)面,天(tian)(tian)牛(niu)四周環水(shui)(shui),局促不(bu)安,頻頻揮動(dong)觸角,形同釣(diao)魚(yu)(yu),魚(yu)(yu)若離水(shui)(shui),則(ze)釣(diao)魚(yu)(yu)成功。如(ru)(ru)兩蟲比賽(sai)(sai)(sai),以(yi)先釣(diao)起(qi)者為勝,十分(fen)有趣(qu)。天(tian)(tian)牛(niu)年(nian)齡(ling)(ling)稍大些(xie)的(de)有手指那(nei)么粗,年(nian)齡(ling)(ling)小一(yi)(yi)(yi)(yi)(yi)(yi)些(xie)的(de)差不(bu)多(duo)(duo)(duo)只有鉛筆(bi)一(yi)(yi)(yi)(yi)(yi)(yi)般細(xi)。
天牛(niu)一(yi)般(ban)(ban)以(yi)幼(you)蟲(chong)(chong)或成(cheng)(cheng)(cheng)(cheng)蟲(chong)(chong)在(zai)樹(shu)(shu)干(gan)(gan)內(nei)越冬。成(cheng)(cheng)(cheng)(cheng)蟲(chong)(chong)羽化后(hou),有的(de)(de)(de)(de)(de)需(xu)進行補充營養,取食(shi)(shi)花粉(fen)、嫩(nen)枝、嫩(nen)葉、樹(shu)(shu)皮、樹(shu)(shu)汁(zhi)或果實、菌類等,有的(de)(de)(de)(de)(de)不(bu)需(xu)補充營養。成(cheng)(cheng)(cheng)(cheng)蟲(chong)(chong)壽命一(yi)般(ban)(ban)10余(yu)天至(zhi)1~2個月;但在(zai)蛹室內(nei)越冬的(de)(de)(de)(de)(de)成(cheng)(cheng)(cheng)(cheng)蟲(chong)(chong)可達7~8個月,雄蟲(chong)(chong)壽命比雌蟲(chong)(chong)短。成(cheng)(cheng)(cheng)(cheng)蟲(chong)(chong)活動時(shi)間與復眼小眼面(mian)粗、細有關(guan),一(yi)般(ban)(ban)小眼面(mian)粗的(de)(de)(de)(de)(de),多在(zai)晚(wan)上活動,有趨光(guang)性;小眼面(mian)細的(de)(de)(de)(de)(de),多在(zai)白天活動。成(cheng)(cheng)(cheng)(cheng)蟲(chong)(chong)產(chan)卵(luan)(luan)方式(shi)與口器(qi)形式(shi)有關(guan),一(yi)般(ban)(ban)前(qian)口式(shi)的(de)(de)(de)(de)(de)成(cheng)(cheng)(cheng)(cheng)蟲(chong)(chong)產(chan)卵(luan)(luan)時(shi)將卵(luan)(luan)直(zhi)接產(chan)入粗糙(cao)樹(shu)(shu)皮或裂縫中(zhong);下口式(shi)的(de)(de)(de)(de)(de)成(cheng)(cheng)(cheng)(cheng)蟲(chong)(chong)先(xian)在(zai)樹(shu)(shu)干(gan)(gan)上咬成(cheng)(cheng)(cheng)(cheng)刻槽,然(ran)后(hou)將卵(luan)(luan)產(chan)在(zai)刻槽內(nei)。天牛(niu)主(zhu)要以(yi)幼(you)蟲(chong)(chong)蛀食(shi)(shi),生(sheng)活時(shi)間長(chang),對樹(shu)(shu)干(gan)(gan)危害嚴(yan)重。當卵(luan)(luan)孵(fu)化出幼(you)蟲(chong)(chong)后(hou),初(chu)齡幼(you)蟲(chong)(chong)即(ji)蛀入樹(shu)(shu)干(gan)(gan),最初(chu)在(zai)樹(shu)(shu)皮下取食(shi)(shi),待齡期(qi)(qi)增大后(hou),即(ji)鉆(zhan)入木(mu)質(zhi)部為害,有的(de)(de)(de)(de)(de)種類僅停留在(zai)樹(shu)(shu)皮下生(sheng)活,不(bu)蛀入木(mu)質(zhi)部。幼(you)蟲(chong)(chong)在(zai)樹(shu)(shu)干(gan)(gan)內(nei)活動,蛀食(shi)(shi)隧道(dao)的(de)(de)(de)(de)(de)形狀(zhuang)和(he)長(chang)短隨種類而異。幼(you)蟲(chong)(chong)在(zai)樹(shu)(shu)干(gan)(gan)或枝條(tiao)上蛀食(shi)(shi),在(zai)一(yi)定距(ju)離內(nei)向樹(shu)(shu)皮上開口作為通(tong)氣孔,向外推出排(pai)泄(xie)物和(he)木(mu)屑。幼(you)蟲(chong)(chong)老熟(shu)后(hou)即(ji)筑成(cheng)(cheng)(cheng)(cheng)較寬的(de)(de)(de)(de)(de)蛹室,兩端以(yi)纖維和(he)木(mu)屑堵塞,而在(zai)其(qi)中(zhong)化蛹。蛹期(qi)(qi)約10~20多天。
天(tian)(tian)(tian)牛(niu)(niu)的幼蟲(chong)蛀食樹(shu)干(gan)和(he)樹(shu)枝,影響樹(shu)木(mu)(mu)的生(sheng)(sheng)長發育,使樹(shu)勢(shi)衰(shuai)弱,導致病菌(jun)侵入(ru),也易(yi)被風折斷。受害嚴(yan)重時,整株死亡,木(mu)(mu)材(cai)被蛀,失(shi)去工藝價值。天(tian)(tian)(tian)牛(niu)(niu)主要是木(mu)(mu)本植(zhi)物(wu)的害蟲(chong),在(zai)幼蟲(chong)期蛀蝕樹(shu)干(gan)、枝條及(ji)根(gen)部。有一部分為(wei)害草本植(zhi)物(wu),幼蟲(chong)生(sheng)(sheng)活于莖或根(gen)內,如(ru)菊天(tian)(tian)(tian)牛(niu)(niu)、瓜藤天(tian)(tian)(tian)牛(niu)(niu)等(deng)。個別種類如(ru)棉蒴天(tian)(tian)(tian)牛(niu)(niu),則為(wei)害棉蒴。還有少(shao)數種類,幼蟲(chong)不生(sheng)(sheng)活在(zai)植(zhi)物(wu)組織內,而(er)是在(zai)土壤(rang)中取食根(gen)部,如(ru)大牙及(ji)曲牙鋸天(tian)(tian)(tian)牛(niu)(niu)、草天(tian)(tian)(tian)牛(niu)(niu)等(deng)等(deng)。
關于成蟲(chong)的(de)(de)食(shi)(shi)性,已知(zhi)有(you)取(qu)食(shi)(shi)花粉(fen)、嫩樹(shu)皮、嫩枝、葉、根、樹(shu)汁、果實、菌(jun)類等不同習性。一般說來,花天牛類常以(yi)花粉(fen)為食(shi)(shi)。溝脛天牛類常食(shi)(shi)害嫩樹(shu)皮、嫩枝和葉。其它(ta)亞(ya)科(ke)的(de)(de)成蟲(chong)亦(yi)有(you)取(qu)食(shi)(shi)的(de)(de),亦(yi)有(you)一部分可能(neng)并不取(qu)食(shi)(shi)。在同一亞(ya)科(ke)內食(shi)(shi)性的(de)(de)變異亦(yi)很(hen)大。
天(tian)牛(niu)(niu)生(sheng)(sheng)活(huo)(huo)(huo)史(shi)的(de)(de)(de)(de)長短依種類(lei)(lei)(lei)而(er)(er)異,有(you)(you)(you)一(yi)(yi)年(nian)完(wan)(wan)成(cheng)(cheng)(cheng)1代或(huo)(huo)(huo)2代的(de)(de)(de)(de),也有(you)(you)(you)二(er)(er)、三(san)年(nian)甚至四、五年(nian)完(wan)(wan)成(cheng)(cheng)(cheng)1代的(de)(de)(de)(de)。同(tong)(tong)一(yi)(yi)種類(lei)(lei)(lei)在(zai)不(bu)(bu)同(tong)(tong)地域的(de)(de)(de)(de)生(sheng)(sheng)活(huo)(huo)(huo)史(shi)有(you)(you)(you)時亦很(hen)不(bu)(bu)同(tong)(tong),如黃(huang)星桑天(tian)牛(niu)(niu)在(zai)江蘇(su)需三(san)年(nian)完(wan)(wan)成(cheng)(cheng)(cheng)一(yi)(yi)世代,而(er)(er)在(zai)廣東則(ze)一(yi)(yi)年(nian)發生(sheng)(sheng)兩代。由于(yu)(yu)幼蟲(chong)(chong)(chong)(chong)的(de)(de)(de)(de)隱藏生(sheng)(sheng)活(huo)(huo)(huo),對(dui)它們(men)進生(sheng)(sheng)活(huo)(huo)(huo)史(shi)觀察很(hen)有(you)(you)(you)困難。又由于(yu)(yu)寄主植物(wu)的(de)(de)(de)(de)條件如老幼、健(jian)康、干濕程度(du)等,對(dui)幼蟲(chong)(chong)(chong)(chong)的(de)(de)(de)(de)長發育影響很(hen)大。不(bu)(bu)良條件常引(yin)起幼蟲(chong)(chong)(chong)(chong)的(de)(de)(de)(de)滯(zhi)育而(er)(er)使生(sheng)(sheng)活(huo)(huo)(huo)世代大大地延長。所以(yi)同(tong)(tong)-種類(lei)(lei)(lei)在(zai)同(tong)(tong)一(yi)(yi)地區內可(ke)能(neng)呈現(xian)不(bu)(bu)同(tong)(tong)的(de)(de)(de)(de)發育過(guo)程。文獻上有(you)(you)(you)許多(duo)(duo)關于(yu)(yu)長壽(shou)幼蟲(chong)(chong)(chong)(chong)的(de)(de)(de)(de)記(ji),這些大都(dou)是根據木材制成(cheng)(cheng)(cheng)了家具后(hou),經過(guo)若(ruo)干年(nian)代,忽(hu)然發現(xian)其中尚有(you)(you)(you)生(sheng)(sheng)存(cun)的(de)(de)(de)(de)天(tian)幼蟲(chong)(chong)(chong)(chong),或(huo)(huo)(huo)者天(tian)牛(niu)(niu)忽(hu)然羽(yu)化而(er)(er)此(ci)證明它在(zai)木器內已生(sheng)(sheng)活(huo)(huo)(huo)了很(hen)多(duo)(duo)年(nian)代。已有(you)(you)(you)很(hen)多(duo)(duo)這樣的(de)(de)(de)(de)例子,證明天(tian)牛(niu)(niu)幼蟲(chong)(chong)(chong)(chong)可(ke)以(yi)生(sheng)(sheng)活(huo)(huo)(huo)到(dao)一(yi)(yi)、二(er)(er)十(shi)年(nian),而(er)(er)最高的(de)(de)(de)(de)2個記(ji)錄是40年(nian)和45年(nian)。天(tian)牛(niu)(niu)一(yi)(yi)般以(yi)幼蟲(chong)(chong)(chong)(chong)越冬,或(huo)(huo)(huo)以(yi)成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong)(chong)在(zai)蛹室(shi)內越冬,即上一(yi)(yi)年(nian)秋(qiu)冬之(zhi)際羽(yu)化的(de)(de)(de)(de)成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong)(chong),留在(zai)蛹室(shi)內到(dao)翌年(nian)春夏間才出(chu)來。成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong)(chong)的(de)(de)(de)(de)壽(shou)命一(yi)(yi)般不(bu)(bu)長,十(shi)數天(tian)到(dao)一(yi)(yi)、二(er)(er)個月(yue),但在(zai)蛹室(shi)內越冬的(de)(de)(de)(de)成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong)(chong)可(ke)能(neng)達到(dao)七、八(ba)個月(yue)。雄蟲(chong)(chong)(chong)(chong)壽(shou)命一(yi)(yi)般較(jiao)雌蟲(chong)(chong)(chong)(chong)為短。成(cheng)(cheng)(cheng)蟲(chong)(chong)(chong)(chong)活(huo)(huo)(huo)動(dong)的(de)(de)(de)(de)時間在(zai)各種類(lei)(lei)(lei)間也各有(you)(you)(you)不(bu)(bu)同(tong)(tong),有(you)(you)(you)的(de)(de)(de)(de)在(zai)白天(tian)日光(guang)下(xia)活(huo)(huo)(huo)動(dong),活(huo)(huo)(huo)躍的(de)(de)(de)(de)是花天(tian)牛(niu)(niu)類(lei)(lei)(lei);有(you)(you)(you)的(de)(de)(de)(de)則(ze)在(zai)夜晚(wan)或(huo)(huo)(huo)陰天(tian)活(huo)(huo)(huo)動(dong),或(huo)(huo)(huo)整(zheng)晚(wan)都(dou)能(neng)活(huo)(huo)(huo)動(dong)。
產(chan)(chan)卵(luan)(luan)(luan)方式(shi):主要有(you)兩種(zhong),一(yi)種(zhong)是雌蟲在(zai)產(chan)(chan)前先用上顎咬破樹皮(特別是溝(gou)脛天牛(niu)), 然后(hou)用產(chan)(chan)卵(luan)(luan)(luan)管插入,每孔(kong)產(chan)(chan)卵(luan)(luan)(luan)一(yi)粒,也有(you)產(chan)(chan)多粒的(de)。這樣形成的(de)產(chan)(chan)卵(luan)(luan)(luan)孔(kong),其形狀大小(xiao)在(zai)各種(zhong)類間常有(you)不同,有(you)的(de)很(hen)顯著,在(zai)防治上可作搜滅蟲卵(luan)(luan)(luan)的(de)指示(shi)。另一(yi)種(zhong)產(chan)(chan)卵(luan)(luan)(luan)方式(shi)不先咬孔(kong),而是直接用產(chan)(chan)卵(luan)(luan)(luan)管在(zai)樹皮縫隙(xi)內(nei)產(chan)(chan)卵(luan)(luan)(luan)。在(zai)少(shao)數情況下(xia),也有(you)產(chan)(chan)在(zai)枝干(gan)光滑部分的(de)。士居(ju)種(zhong)類產(chan)(chan)卵(luan)(luan)(luan)于土壤內(nei)。
初孵(fu)的(de)幼(you)蟲(chong)一般先(xian)在(zai)(zai)(zai)皮下蛀食,經過或長或短(duan)的(de)時期后才(cai)深(shen)入到木(mu)質(zhi)部(bu)分。少數種(zhong)(zhong)類(lei)僅(jin)(jin)在(zai)(zai)(zai)皮下蛀蝕。也有(you)(you)(you)的(de)種(zhong)(zhong)類(lei)則穿鑿不(bu)(bu)深(shen),僅(jin)(jin)在(zai)(zai)(zai)邊材部(bu)為害(hai)。許多種(zhong)(zhong)類(lei)侵害(hai)基干或粗枝(zhi),有(you)(you)(you)的(de)在(zai)(zai)(zai)根(gen)干,有(you)(you)(you)的(de)則在(zai)(zai)(zai)枝(zhi)條(tiao)蛀蝕。幼(you)蟲(chong)蛀蝕時穿鑿各種(zhong)(zhong)坑(keng)道(dao),或上或下,或左或右,或彎或直,隨種(zhong)(zhong)類(lei)而(er)異,但也有(you)(you)(you)許多種(zhong)(zhong)類(lei)的(de)坑(keng)道(dao)很(hen)不(bu)(bu)規則。在(zai)(zai)(zai)坑(keng)道(dao)內(nei)常充滿(man)蟲(chong)糞(fen)及纖維質(zhi)木(mu)屑.有(you)(you)(you)時蟲(chong)糞(fen)木(mu)屑由蟲(chong)孔向外排出(chu),有(you)(you)(you)時受害(hai)處(chu)并有(you)(you)(you)樹汁流出(chu)。老熟幼(you)蟲(chong)常筑(zhu)成較寬(kuan)的(de)坑(keng)道(dao)作為蛹室,兩(liang)端(duan)以纖維木(mu)屑封閉,在(zai)(zai)(zai)其中(zhong)化蛹。