七星瓢蟲(學名:Coccinella septempunctata)是瓢蟲科、瓢蟲屬昆蟲。成蟲體(ti)長5.2-6.5毫米,寬4.0-5.6毫米;身(shen)體(ti)卵圓形(xing),背(bei)(bei)部(bu)拱起,呈水(shui)瓢狀;頭(tou)黑(hei)(hei)(hei)(hei)(hei)色(se)(se)(se)、復眼黑(hei)(hei)(hei)(hei)(hei)色(se)(se)(se),內側(ce)(ce)凹(ao)入處各有(you)(you)(you)一淡黃(huang)(huang)色(se)(se)(se)點;觸(chu)角(jiao)褐色(se)(se)(se);口器黑(hei)(hei)(hei)(hei)(hei)色(se)(se)(se);上(shang)額外側(ce)(ce)為黃(huang)(huang)色(se)(se)(se);前(qian)(qian)胸(xiong)背(bei)(bei)板(ban)黑(hei)(hei)(hei)(hei)(hei),前(qian)(qian)上(shang)角(jiao)各有(you)(you)(you)1個較大的(de)近方形(xing)的(de)淡黃(huang)(huang)地(di);小盾(dun)(dun)片黑(hei)(hei)(hei)(hei)(hei)色(se)(se)(se);鞘翅紅色(se)(se)(se)或橙(cheng)黃(huang)(huang)色(se)(se)(se),兩側(ce)(ce)共有(you)(you)(you)7個黑(hei)(hei)(hei)(hei)(hei)斑(ban),左右(you)兩側(ce)(ce)各有(you)(you)(you)3個黑(hei)(hei)(hei)(hei)(hei)點,接合處前(qian)(qian)方尚有(you)(you)(you)一個更大的(de)黑(hei)(hei)(hei)(hei)(hei)點;翅基部(bu)在小盾(dun)(dun)片兩側(ce)(ce)各有(you)(you)(you)1個三角(jiao)形(xing)白(bai)斑(ban);體(ti)腹(fu)及足黑(hei)(hei)(hei)(hei)(hei)色(se)(se)(se)。
七(qi)星(xing)瓢(piao)(piao)蟲(chong)(chong)一生要經過卵、幼蟲(chong)(chong)、蛹和(he)(he)(he)成(cheng)蟲(chong)(chong)4個不(bu)同發育階(jie)段,各蟲(chong)(chong)態的(de)發育歷期,主要受食(shi)物(wu)和(he)(he)(he)溫度的(de)影響。七(qi)星(xing)瓢(piao)(piao)蟲(chong)(chong)是遷飛性昆(kun)蟲(chong)(chong),成(cheng)蟲(chong)(chong)和(he)(he)(he)幼蟲(chong)(chong)的(de)覓食(shi)行為(wei)屬于(yu)廣域搜(sou)索與區(qu)域集中搜(sou)索行為(wei)的(de)轉換。七(qi)星(xing)瓢(piao)(piao)蟲(chong)(chong)主要以蚜蟲(chong)(chong)為(wei)食(shi),有時還取食(shi)小土粒、真(zhen)菌(jun)孢子和(he)(he)(he)一些小型昆(kun)蟲(chong)(chong),秋天(tian)還常(chang)常(chang)取食(shi)植物(wu)的(de)花粉。廣泛分布于(yu)非(fei)洲、歐(ou)洲、亞洲。
七星瓢蟲的名(ming)稱由其(qi)鞘翅(chi)上(shang)(shang)的7個黑色斑點而來,但(dan)是其(qi)身上(shang)(shang)的斑點數量(liang)是各不相(xiang)同的。
七星(xing)瓢蟲(chong)幼(you)(you)(you)蟲(chong)與異(yi)色(se)(se)(se)(se)瓢蟲(chong)幼(you)(you)(you)蟲(chong)相似。區別在于七星(xing)瓢蟲(chong)幼(you)(you)(you)蟲(chong)淡藍灰(hui)色(se)(se)(se)(se),異(yi)色(se)(se)(se)(se)瓢蟲(chong)幼(you)(you)(you)蟲(chong)灰(hui)黑(hei)色(se)(se)(se)(se)。七星(xing)瓢蟲(chong)幼(you)(you)(you)蟲(chong)腹部背(bei)面(mian)(mian)和側(ce)面(mian)(mian),每節(jie)生(sheng)有(you)六(liu)個短(duan)刺;第(di)(di)一、四(si)兩節(jie)背(bei)面(mian)(mian)兩側(ce),各(ge)有(you)一對黃色(se)(se)(se)(se)短(duan)刺;其余各(ge)節(jie)短(duan)刺皆為黑(hei)色(se)(se)(se)(se)。異(yi)色(se)(se)(se)(se)瓢蟲(chong)幼(you)(you)(you)蟲(chong)腹部背(bei)面(mian)(mian)兩側(ce),每節(jie)生(sheng)有(you)六(liu)個分(fen)枝(zhi)(zhi)的枝(zhi)(zhi)刺,第(di)(di)四(si)兩節(jie)的背(bei)面(mian)(mian)兩側(ce),各(ge)有(you)一對桔(jie)紅色(se)(se)(se)(se)枝(zhi)(zhi)刺,其中(zhong)第(di)(di)一節(jie)的兩個枝(zhi)(zhi)刺基部相連,形成一個桔(jie)紅色(se)(se)(se)(se)大斑。
某(mou)些(xie)金花蟲類的(de)卵(luan),如柳(liu)(liu)葉(xie)甲的(de)卵(luan)和(he)七(qi)(qi)(qi)星瓢(piao)蟲的(de)卵(luan)很(hen)相(xiang)似(si),常(chang)被誤(wu)認為七(qi)(qi)(qi)星瓢(piao)蟲卵(luan),但(dan)兩者是有(you)明顯區別的(de):①兩者產卵(luan)習性不同,柳(liu)(liu)葉(xie)甲常(chang)在(zai)柳(liu)(liu)葉(xie)上產卵(luan),而七(qi)(qi)(qi)星瓢(piao)蟲通常(chang)不在(zai)樹葉(xie)上產卵(luan);②柳(liu)(liu)葉(xie)甲卵(luan)粒(li)是長圓形,卵(luan)塊排列疏(shu)松而不整齊(qi),七(qi)(qi)(qi)星瓢(piao)蟲的(de)卵(luan)粒(li)是梭形,排列緊密而整齊(qi)。
七星(xing)瓢蟲廣泛分(fen)布于(yu)北美洲、歐(ou)洲、亞洲。在(zai)中(zhong)國分(fen)布于(yu)東(dong)(dong)北、華北、華中(zhong)、西(xi)北、華東(dong)(dong)和西(xi)南地區。
中文名(ming)(ming) 拉丁學名(ming)(ming) 命名(ming)(ming)者及年代
七星瓢蟲(chong)日本(ben)亞(ya)種 Coccinella septempunctata brucki Mulsant,1866
七星瓢蟲指名亞種 Coccinella septempunctata septempunctata Linnaeus,1758
七星瓢(piao)蟲(chong)體長5.2-7.0毫米,寬(kuan)4.0-5.6毫米。蟲(chong)體卵圓(yuan)形,背面光滑(hua)并拱超呈半球(qiu)狀。剛羽(yu)化(hua)的成蟲(chong)柔(rou)軟,嫩黃色(se),2-3小(xiao)時后,整個(ge)體軀和鞘翅(chi)變(bian)硬(ying),顏色(se)由黃變(bian)紅(hong),同時鞘翅(chi)上出(chu)現7個(ge)黑色(se)斑點。
七(qi)(qi)星瓢(piao)蟲和(he)其它昆蟲一(yi)樣,體軀分(fen)為(wei)(wei)頭(tou)(tou)(tou)、胸、腹(fu)(fu)(fu)(fu)(fu)三部(bu)分(fen)。各部(bu)分(fen)均由若干個體節(jie)組(zu)成。頭(tou)(tou)(tou)部(bu)生有(you)(you)一(yi)對(dui)(dui)觸角(jiao),一(yi)對(dui)(dui)復(fu)眼和(he)口(kou)(kou)器,口(kou)(kou)器兩側(ce)有(you)(you)一(yi)對(dui)(dui)下(xia)(xia)顎須。頭(tou)(tou)(tou)部(bu)較小,經(jing)常后(hou)縮在(zai)發達的(de)(de)前(qian)(qian)胸背(bei)板之下(xia)(xia),胸部(bu)生有(you)(you)兩對(dui)(dui)翅(chi),三對(dui)(dui)足。腹(fu)(fu)(fu)(fu)(fu)部(bu)八節(jie),但(dan)腹(fu)(fu)(fu)(fu)(fu)面(mian)只能(neng)看到6一(yi)7節(jie)。腹(fu)(fu)(fu)(fu)(fu)部(bu)末端有(you)(you)外生殖器和(he)肛門。胸部(bu)和(he)腹(fu)(fu)(fu)(fu)(fu)部(bu)側(ce)面(mian)生有(you)(you)氣孔,是呼(hu)吸時(shi)氣體進出(chu)的(de)(de)通道,七(qi)(qi)星瓢(piao)蟲和(he)許多有(you)(you)硬翅(chi)鞘(qiao)的(de)(de)昆蟲(分(fen)類學上稱鞘(qiao)翅(chi)目)一(yi)樣,有(you)(you)一(yi)對(dui)(dui)角(jiao)質(zhi)堅硬的(de)(de)前(qian)(qian)翅(chi)。平時(shi),這一(yi)對(dui)(dui)的(de)(de)翅(chi)并合,覆蓋在(zai)胸腹(fu)(fu)(fu)(fu)(fu)部(bu)的(de)(de)背(bei)上。后(hou)翅(chi)為(wei)(wei)半透明的(de)(de)膜(mo)質(zhi),平時(shi)折疊(die),匿(ni)于(yu)前(qian)(qian)翅(chi)之下(xia)(xia)。七(qi)(qi)星瓢(piao)蟲的(de)(de)下(xia)(xia)顎須末節(jie)呈斧狀,足的(de)(de)咐節(jie)是四節(jie),但(dan)第(di)三節(jie)特別(bie)小,并匿(ni)于(yu)第(di)二節(jie)的(de)(de)兩個分(fen)葉之間,粗看很象是三節(jie)。
七(qi)星(xing)瓢蟲(chong)雌雄(xiong)形態,斑(ban)紋相同,雌蟲(chong)常較雄(xiong)蟲(chong)大(da)些。兩者可(ke)靠的(de)鑒(jian)別(bie)特征是(shi)雄(xiong)蟲(chong)腹(fu)部腹(fu)面末端(duan),有一小的(de)橫的(de)凹陷,而(er)雌蟲(chong)則平坦而(er)光滑,無此(ci)凹陷。
七星瓢蟲幼(you)蟲體(ti)(ti)表有(you)一(yi)(yi)層較堅硬的(de)(de)(de)表皮(pi),它的(de)(de)(de)伸展性有(you)限(xian),所以(yi)生(sheng)長(chang)到一(yi)(yi)定階段,必須蛻(tui)去老皮(pi),著生(sheng)新皮(pi),才(cai)能繼(ji)續(xu)成長(chang)。每蛻(tui)一(yi)(yi)次(ci)(ci)皮(pi),就增(zeng)加一(yi)(yi)個(ge)齡(ling)期(qi),幼(you)蟲共蛻(tui)三(san)次(ci)(ci)皮(pi),有(you)四(si)(si)個(ge)齡(ling)期(qi)。初孵幼(you)蟲(一(yi)(yi)齡(ling))身體(ti)(ti)很小,只有(you)2-3毫米(mi),孵化后,就聚(ju)集(ji)在原卵塊的(de)(de)(de)殘殼上,約(yue)經8-12小時(shi),開(kai)始(shi)分散取食。約(yue)兩(liang)(liang)(liang)天后,蛻(tui)皮(pi)變為二齡(ling),此時(shi)體(ti)(ti)長(chang)已(yi)增(zeng)大一(yi)(yi)倍多,腹部第(di)一(yi)(yi)節背面兩(liang)(liang)(liang)側,出現兩(liang)(liang)(liang)個(ge)黃(huang)色肉瘤(liu),三(san)齡(ling)幼(you)蟲除體(ti)(ti)長(chang)加大外,腹部第(di)一(yi)(yi)、四(si)(si)兩(liang)(liang)(liang)節的(de)(de)(de)背面兩(liang)(liang)(liang)側,各有(you)一(yi)(yi)對(dui)黃(huang)色肉瘤(liu),但第(di)四(si)(si)節的(de)(de)(de)肉瘤(liu)不(bu)很明(ming)顯(xian),要用(yong)放大鏡才(cai)能看清楚,到四(si)(si)齡(ling)時(shi),這兩(liang)(liang)(liang)對(dui)肉瘤(liu)都非常明(ming)顯(xian)。當(dang)幼(you)蟲老熟時(shi),體(ti)(ti)形變粗,最后以(yi)尾端(duan)固著在植株等附著物上,準備化蛹(yong)。
體(ti)長7毫米,寬5毫米。體(ti)黃色(se)。前(qian)(qian)胸背(bei)(bei)板(ban)前(qian)(qian)緣有(you)4個(ge)黑(hei)點,中(zhong)央2個(ge)呈三角(jiao)形,前(qian)(qian)胸背(bei)(bei)板(ban)后緣中(zhong)央有(you)2個(ge)黑(hei)點,兩側(ce)角(jiao)有(you)2個(ge)黑(hei)斑。中(zhong)胸背(bei)(bei)板(ban)有(you)2個(ge)黑(hei)斑。腹(fu)部第2-6節背(bei)(bei)面左右有(you)4個(ge)黑(hei)斑。腹(fu)末帶有(you)末齡幼蟲的(de)黑(hei)色(se)蛻皮。
七星瓢(piao)(piao)蟲(chong)(chong)(chong)的(de)(de)(de)(de)下(xia)顎須是它的(de)(de)(de)(de)主(zhu)要(yao)觸覺(jue)(jue)和嗅覺(jue)(jue)器官。七星瓢(piao)(piao)蟲(chong)(chong)(chong)經常(chang)在(zai)(zai)蚜蟲(chong)(chong)(chong)的(de)(de)(de)(de)寄主(zhu)植物上(shang)爬動(dong)、搜索,當下(xia)顎須觸到蚜蟲(chong)(chong)(chong)時(shi),能迅速地用上(shang)顎咬(yao)住(zhu),將蚜蟲(chong)(chong)(chong)吞(tun)食(shi)。如(ru)果(guo)下(xia)顎須沒有觸到,即使蚜蟲(chong)(chong)(chong)就在(zai)(zai)它的(de)(de)(de)(de)眼前,似(si)乎(hu)也不能發(fa)現。七星瓢(piao)(piao)蟲(chong)(chong)(chong)成(cheng)蟲(chong)(chong)(chong)和幼(you)蟲(chong)(chong)(chong)雖都取食(shi)蚜蟲(chong)(chong)(chong),但因(yin)蟲(chong)(chong)(chong)態不同(tong),口(kou)(kou)器結構不同(tong),取食(shi)方法也有差別。成(cheng)蟲(chong)(chong)(chong)取食(shi)時(shi),通常(chang)將蚜蟲(chong)(chong)(chong)咬(yao)住(zhu),經過口(kou)(kou)器的(de)(de)(de)(de)簡單咀嚼后,將蚜蟲(chong)(chong)(chong)軀體(ti)、附(fu)肢等完全吞(tun)下(xia)。大齡幼(you)蟲(chong)(chong)(chong)取食(shi)基本上(shang)和成(cheng)蟲(chong)(chong)(chong)一樣。但初齡幼(you)蟲(chong)(chong)(chong)因(yin)口(kou)(kou)器小(xiao)(xiao),吞(tun)食(shi)力差,取食(shi)時(shi)常(chang)在(zai)(zai)蚜蟲(chong)(chong)(chong)體(ti)上(shang)咬(yao)一個孔,吸(xi)食(shi)汁液,最后留(liu)下(xia)蚜體(ti)殘(can)殼。一頭七星瓢(piao)(piao)蟲(chong)(chong)(chong)的(de)(de)(de)(de)成(cheng)蟲(chong)(chong)(chong),平均一天吃(chi)棉(mian)蚜100-120頭,吃(chi)菜蚜147頭,吃(chi)杏(xing)蚜59頭。幼(you)蟲(chong)(chong)(chong)食(shi)蚜量則因(yin)齡期(qi)的(de)(de)(de)(de)大小(xiao)(xiao)而不同(tong),齡期(qi)小(xiao)(xiao)吃(chi)的(de)(de)(de)(de)少,齡期(qi)大吃(chi)的(de)(de)(de)(de)多。
七(qi)星瓢蟲(chong)有吃(chi)卵(luan)和(he)互相捕(bu)食(shi)(shi)的(de)(de)習性。在食(shi)(shi)物不(bu)足的(de)(de)情況下(xia),七(qi)星瓢蟲(chong)成(cheng)蟲(chong)很(hen)容易吃(chi)掉(diao)(diao)已產下(xia)的(de)(de)卵(luan)塊。即使有充足的(de)(de)蚜蟲(chong),它們也(ye)喜歡吃(chi)卵(luan);幼(you)蟲(chong)則(ze)常互相捕(bu)食(shi)(shi)。同一卵(luan)塊早孵(fu)出的(de)(de)個體(ti),常吃(chi)掉(diao)(diao)尚未孵(fu)化的(de)(de)卵(luan)粒。大齡(ling)(ling)(ling)幼(you)蟲(chong)常吃(chi)掉(diao)(diao)小齡(ling)(ling)(ling)幼(you)蟲(chong)。蛹也(ye)常被(bei)成(cheng)蟲(chong)和(he)大齡(ling)(ling)(ling)幼(you)蟲(chong)吃(chi)掉(diao)(diao)。
七(qi)星(xing)(xing)瓢蟲(chong)(chong)(chong)(chong)雖然主要是吃蚜蟲(chong)(chong)(chong)(chong),但并不(bu)僅僅限于以蚜蟲(chong)(chong)(chong)(chong)為食(shi)。中國(guo)北京(jing)的金山腳下(xia),在秋天蒿草和荊(jing)條上并沒有蚜蟲(chong)(chong)(chong)(chong),七(qi)星(xing)(xing)瓢蟲(chong)(chong)(chong)(chong)成蟲(chong)(chong)(chong)(chong)卻(que)群集其上,數量很多。經過仔(zi)細觀察和消化道解(jie)削并在顯微鏡下(xia)檢查,發現七(qi)星(xing)(xing)瓢蟲(chong)(chong)(chong)(chong)在早春不(bu)僅吃蚜蟲(chong)(chong)(chong)(chong),還取食(shi)小(xiao)土粒、真菌孢(bao)子和一些小(xiao)型昆蟲(chong)(chong)(chong)(chong)。秋天,七(qi)星(xing)(xing)瓢蟲(chong)(chong)(chong)(chong)則常(chang)常(chang)取食(shi)植物的花(hua)粉。
七星(xing)瓢(piao)(piao)蟲(chong)(chong)一生經過(guo)卵、幼蟲(chong)(chong)、蛹(yong)、成(cheng)蟲(chong)(chong)等四(si)個發(fa)育(yu)階段。七星(xing)瓢(piao)(piao)蟲(chong)(chong)各蟲(chong)(chong)態的(de)發(fa)育(yu)歷期(qi)(qi),主要(yao)受食物(wu)和(he)溫(wen)(wen)度(du)(du)的(de)影響(xiang)(xiang)。在(zai)(zai)(zai)適宜的(de)食物(wu)條件(jian)下,溫(wen)(wen)度(du)(du)不(bu)同,發(fa)育(yu)的(de)速率(lv)(lv)也(ye)不(bu)相同。幼蟲(chong)(chong)期(qi)(qi)在(zai)(zai)(zai)15℃條件(jian)下,長(chang)達44.1天(tian),而在(zai)(zai)(zai)24-26℃時(shi)(shi)只有(you)(you)8-9.4天(tian)。高于30℃發(fa)育(yu)速率(lv)(lv)又逐(zhu)漸降(jiang)低,33℃時(shi)(shi)幼蟲(chong)(chong)期(qi)(qi)又延長(chang)到16.2天(tian)。溫(wen)(wen)度(du)(du)不(bu)適宜時(shi)(shi)發(fa)育(yu)緩慢的(de)原(yuan)因,除直(zhi)接受溫(wen)(wen)度(du)(du)影響(xiang)(xiang)外,取(qu)食速率(lv)(lv)低也(ye)有(you)(you)關系。一頭(tou)四(si)齡(ling)幼蟲(chong)(chong)在(zai)(zai)(zai)25℃左右時(shi)(shi),每天(tian)取(qu)食一百(bai)多頭(tou)蚜蟲(chong)(chong),而在(zai)(zai)(zai)15℃時(shi)(shi),僅取(qu)食十幾頭(tou)。
七星瓢蟲(chong)(chong)以(yi)成(cheng)蟲(chong)(chong)越(yue)冬(dong)(dong),多選擇較干燥、溫(wen)暖的(de)枯枝(zhi)落葉(xie)下(xia)(xia)、雜草基部(bu)近地(di)面的(de)土塊下(xia)(xia)、土縫中(zhong)、樹皮裂(lie)縫處潛(qian)伏,蟄伏越(yue)冬(dong)(dong)后,若遇(yu)溫(wen)度(du)回暖,又(you)爬出越(yue)冬(dong)(dong)場所活動。出蟄后的(de)七星瓢蟲(chong)(chong)迅速在林木、雜草和(he)作(zuo)物之間活動,特別是帶蚜蟲(chong)(chong)的(de)作(zuo)物與(yu)開花果木上(shang)。七星瓢蟲(chong)(chong)是遷飛性(xing)昆蟲(chong)(chong),成(cheng)蟲(chong)(chong)和(he)幼蟲(chong)(chong)的(de)覓(mi)食(shi)行為(wei)屬于廣域搜索與(yu)區(qu)域集中(zhong)搜索行為(wei)的(de)轉換。
七星瓢蟲有(you)著驚人的(de)(de)避敵本(ben)領。只要有(you)天敵來擾或受到(dao)外(wai)界突然的(de)(de)刺(ci)(ci)激(ji),它就(jiu)(jiu)會發生一(yi)種叫(jiao)做“神(shen)經休(xiu)克”現象,有(you)點像失(shi)去(qu)(qu)知覺似的(de)(de)一(yi)動不動。“休(xiu)克”過后,受到(dao)刺(ci)(ci)激(ji)的(de)(de)神(shen)經系統恢復正常(chang),它又(you)清醒過來,開始爬行。這(zhe)種“死去(qu)(qu)活來”的(de)(de)舉止,人們(men)稱它“假死”。如果用手去(qu)(qu)捏它,它就(jiu)(jiu)會使出(chu)(chu)第二招(zhao)避敵本(ben)領,在它6條足上的(de)(de)各(ge)關節中間,滲出(chu)(chu)一(yi)種黃色汁液來,這(zhe)些汁液散發出(chu)(chu)來的(de)(de)辣臭味,可使人聞之感到(dao)膩煩,就(jiu)(jiu)連鳥(niao)類(lei)聞到(dao)這(zhe)種怪(guai)味,也(ye)“退(tui)避三(san)舍(she)”。
七(qi)星(xing)瓢(piao)(piao)(piao)蟲(chong)(chong)(chong)(chong)(chong)在(zai)不同季節(jie)的(de)(de)(de)活(huo)動場(chang)所不一樣。冬天(tian),七(qi)星(xing)瓢(piao)(piao)(piao)蟲(chong)(chong)(chong)(chong)(chong)在(zai)小麥和油(you)菜(cai)的(de)(de)(de)根(gen)莖間越冬,也有(you)的(de)(de)(de)在(zai)向陽的(de)(de)(de)土塊、土縫中(zhong)過(guo)冬。春(chun)天(tian),一旦氣溫(wen)升到10℃以上(shang)(shang),越冬的(de)(de)(de)七(qi)星(xing)瓢(piao)(piao)(piao)蟲(chong)(chong)(chong)(chong)(chong)就蘇醒過(guo)來,開始(shi)活(huo)動,在(zai)麥類(lei)和油(you)菜(cai)植物株上(shang)(shang)能找到它。夏天(tian),隨著氣溫(wen)升高(gao)和食(shi)物增多,七(qi)星(xing)瓢(piao)(piao)(piao)蟲(chong)(chong)(chong)(chong)(chong)大量繁殖,凡是有(you)蚜蟲(chong)(chong)(chong)(chong)(chong)和蚧蟲(chong)(chong)(chong)(chong)(chong)寄生的(de)(de)(de)植物,如棉花(hua)、柳(liu)樹、槐樹、榆樹、豆類(lei)等植株上(shang)(shang),都(dou)能找到七(qi)星(xing)瓢(piao)(piao)(piao)蟲(chong)(chong)(chong)(chong)(chong),有(you)時(shi)甚至出現(xian)大批七(qi)星(xing)瓢(piao)(piao)(piao)蟲(chong)(chong)(chong)(chong)(chong)聚集(ji)的(de)(de)(de)景象(xiang)。秋天(tian),田間七(qi)星(xing)瓢(piao)(piao)(piao)蟲(chong)(chong)(chong)(chong)(chong)的(de)(de)(de)數量減(jian)少,它常在(zai)玉米、蘿卜和白(bai)菜(cai)等處(chu)產卵(luan),這時(shi)候,早晚的(de)(de)(de)氣溫(wen)較低,七(qi)星(xing)瓢(piao)(piao)(piao)蟲(chong)(chong)(chong)(chong)(chong)往往隱(yin)蔽(bi)起來,不易發現(xian),需在(zai)上(shang)(shang)午7點鐘以后至太陽下山之前(qian)采集(ji)。
越冬的(de)(de)七(qi)星瓢蟲不食不動,只要(yao)找到,捕(bu)捉很方(fang)便(bian),用手就能捉住。其(qi)他季節的(de)(de)七(qi)星瓢蟲善爬(pa)能飛,可以利用它假死習性,用塑料袋(dai)迅(xun)速套住棲息著七(qi)星瓢蟲的(de)(de)枝條(tiao),抖動一下,七(qi)星瓢蟲立即掉落(luo)在袋(dai)里,接(jie)著,把(ba)枝條(tiao)抽出,扎緊口袋(dai),就可以帶回實驗室。
人工飼(si)養(yang)七星瓢(piao)蟲(chong)(chong),首先要解決飼(si)料(liao)(liao)問題。可以(yi)到野外采(cai)集天然飼(si)料(liao)(liao)蚜(ya)(ya)蟲(chong)(chong),但這種方法費工多,有時(shi)還不易采(cai)到。所以(yi)用人工培(pei)養(yang)大量(liang)(liang)蚜(ya)(ya)蟲(chong)(chong),滿足(zu)七星瓢(piao)蟲(chong)(chong)食用。可用蠶(can)豆苗人工培(pei)養(yang)蚜(ya)(ya)蟲(chong)(chong)。當分栽的蠶(can)豆苗長(chang)出(chu)3-4厘米(mi)高時(shi),把野外采(cai)集的少量(liang)(liang)蚜(ya)(ya)蟲(chong)(chong)放在(zai)(zai)豆苗上,在(zai)(zai)室(shi)溫20-30℃、相對濕度60-70%的條(tiao)件(jian)下(xia)培(pei)養(yang)10-15天,蚜(ya)(ya)蟲(chong)(chong)就能(neng)大量(liang)(liang)繁(fan)殖(zhi),這時(shi)就可用蚜(ya)(ya)蟲(chong)(chong)作七星瓢(piao)蟲(chong)(chong)的飼(si)料(liao)(liao)。
將(jiang)蛹(yong)或成(cheng)(cheng)蟲(chong)(chong)(chong)放入(ru)成(cheng)(cheng)蟲(chong)(chong)(chong)飼(si)(si)(si)養籠(long)(long)(long)內(nei)(nei),每籠(long)(long)(long)放雌蟲(chong)(chong)(chong)500-750頭(tou),并搭(da)配1/4的(de)(de)雄(xiong)蟲(chong)(chong)(chong)。成(cheng)(cheng)蟲(chong)(chong)(chong)喂(wei)人工飼(si)(si)(si)料或蚜蟲(chong)(chong)(chong),每天喂(wei)飼(si)(si)(si)料和(he)加(jia)水(shui)。新羽化的(de)(de)成(cheng)(cheng)蟲(chong)(chong)(chong),經過幾天的(de)(de)取食,逐(zhu)步達(da)到性成(cheng)(cheng)熟,便交尾(wei)產卵(luan)。產卵(luan)時(shi)(shi)間多在晚(wan)上(shang)7-9點鐘。卵(luan)產在籠(long)(long)(long)頂(ding)和(he)內(nei)(nei)側的(de)(de)紙上(shang),收卵(luan)時(shi)(shi),將(jiang)籠(long)(long)(long)內(nei)(nei)的(de)(de)紙取出,換上(shang)新鮮的(de)(de)紙就成(cheng)(cheng)了。收卵(luan)每天1-2次(ci),同時(shi)(shi)換飼(si)(si)(si)料和(he)水(shui)。收卵(luan)時(shi)(shi)先準(zhun)備(bei)一批空飼(si)(si)(si)養籠(long)(long)(long),籠(long)(long)(long)底打(da)開(kai),頂(ding)面(mian)向光,然(ran)后將(jiang)有(you)蟲(chong)(chong)(chong)的(de)(de)籠(long)(long)(long)底面(mian)紗布拆(chai)開(kai),籠(long)(long)(long)底對準(zhun)籠(long)(long)(long)底,成(cheng)(cheng)蟲(chong)(chong)(chong)馬上(shang)向有(you)光的(de)(de)方向集中,進(jin)入(ru)新的(de)(de)籠(long)(long)(long)內(nei)(nei)。
成(cheng)(cheng)蟲(chong)飼養時(shi),如食料不足,就不產卵。成(cheng)(cheng)蟲(chong)在黑暗條件下(xia)活躍,晚(wan)上可適當加光照,減少成(cheng)(cheng)蟲(chong)活動,避免相(xiang)互碰傷(shang)。
七星(xing)瓢蟲(chong)(chong)(chong)(chong)大量繁殖(zhi)后(hou),可(ke)以(yi)放(fang)(fang)到(dao)田(tian)(tian)(tian)間(jian)(jian),幫助人類消滅蚜(ya)蟲(chong)(chong)(chong)(chong)和蚧(jie)蟲(chong)(chong)(chong)(chong)。如棉(mian)田(tian)(tian)(tian)出現大量蚜(ya)蟲(chong)(chong)(chong)(chong)危害(hai),這時(shi)可(ke)以(yi)把七星(xing)瓢蟲(chong)(chong)(chong)(chong)散(san)(san)(san)放(fang)(fang)到(dao)棉(mian)田(tian)(tian)(tian)里(li),它就(jiu)能將(jiang)蚜(ya)蟲(chong)(chong)(chong)(chong)吃(chi)掉。散(san)(san)(san)發(fa)時(shi),在棉(mian)田(tian)(tian)(tian)邊走(zou)(zou)邊放(fang)(fang)七星(xing)瓢蟲(chong)(chong)(chong)(chong),走(zou)(zou)幾步放(fang)(fang)幾只(zhi),以(yi)求散(san)(san)(san)放(fang)(fang)均勻:①掌握好散(san)(san)(san)放(fang)(fang)時(shi)間(jian)(jian),以(yi)傍(bang)晚時(shi)散(san)(san)(san)放(fang)(fang)為宜。因為傍(bang)晚氣溫較(jiao)低,光線(xian)較(jiao)暗,七星(xing)瓢蟲(chong)(chong)(chong)(chong)活動(dong)性(xing)較(jiao)弱(ruo),不(bu)易遷(qian)(qian)飛;②采用成蟲(chong)(chong)(chong)(chong)和幼蟲(chong)(chong)(chong)(chong)混(hun)放(fang)(fang)。因為幼蟲(chong)(chong)(chong)(chong)沒(mei)有遷(qian)(qian)飛能力,不(bu)會逃逸,而它也有吃(chi)蚜(ya)蟲(chong)(chong)(chong)(chong)的本領;③散(san)(san)(san)發(fa)前(qian)一天停(ting)止(zhi)喂食(shi),再(zai)進行散(san)(san)(san)放(fang)(fang),可(ke)以(yi)降低七星(xing)瓢蟲(chong)(chong)(chong)(chong)遷(qian)(qian)飛活動(dong)能力;④散(san)(san)(san)放(fang)(fang)后(hou)兩天內,不(bu)進行中(zhong)耕和其他田(tian)(tian)(tian)間(jian)(jian)管理,以(yi)免使七星(xing)瓢蟲(chong)(chong)(chong)(chong)受驚遷(qian)(qian)逃。
七(qi)星瓢(piao)蟲(chong)卵(luan)通常成(cheng)塊(kuai)地產在莖葉或土塊(kuai)上。卵(luan)粒梭形,豎(shu)立,整齊地排列(lie)成(cheng)塊(kuai)。每個卵(luan)塊(kuai)一般(ban)30粒左右。最多可達百(bai)余粒,少的則僅有幾粒。剛產下(xia)的卵(luan)淡黃色,后逐漸變(bian)為杏(xing)黃色。將孵化時,呈黑渴(ke)色。
新羽(yu)化(hua)的(de)七星(xing)瓢蟲(chong)(chong)成(cheng)蟲(chong)(chong),待(dai)體軀和翅鞘硬化(hua)后(hou)(hou)(hou),便開始(shi)活動(dong)取(qu)食(shi)(shi),3-4天(tian)后(hou)(hou)(hou)交(jiao)尾。七星(xing)瓢蟲(chong)(chong)有多次交(jiao)尾習性,但(dan)經一次交(jiao)尾,雌(ci)蟲(chong)(chong)所產(chan)的(de)卵(luan)(luan)(luan)(luan)(luan)就(jiu)都能孵(fu)化(hua)。秋(qiu)季越(yue)冬代成(cheng)蟲(chong)(chong)交(jiao)尾后(hou)(hou)(hou),雖(sui)活動(dong)取(qu)食(shi)(shi),但(dan)卵(luan)(luan)(luan)(luan)(luan)巢并(bing)不(bu)發育,翌春活動(dong)取(qu)食(shi)(shi)后(hou)(hou)(hou)才開始(shi)產(chan)卵(luan)(luan)(luan)(luan)(luan)。非(fei)越(yue)冬代成(cheng)蟲(chong)(chong)交(jiao)尾3-5天(tian)后(hou)(hou)(hou),便開始(shi)產(chan)卵(luan)(luan)(luan)(luan)(luan)。產(chan)卵(luan)(luan)(luan)(luan)(luan)開始(shi)以(yi)后(hou)(hou)(hou),幾(ji)天(tian)內(nei)就(jiu)達到了(le)(le)高(gao)峰,產(chan)卵(luan)(luan)(luan)(luan)(luan)盛期持(chi)續一個(ge)月左右。在盛期的(de)33天(tian)里,產(chan)下了(le)(le)全部卵(luan)(luan)(luan)(luan)(luan)粒的(de)95%以(yi)上(shang)。產(chan)卵(luan)(luan)(luan)(luan)(luan)盛期,一頭雌(ci)蟲(chong)(chong)一天(tian)可產(chan)好幾(ji)個(ge)卵(luan)(luan)(luan)(luan)(luan)塊(kuai)。七星(xing)瓢蟲(chong)(chong)因取(qu)食(shi)(shi)的(de)蚜蟲(chong)(chong)種類(lei)不(bu)同(tong),產(chan)卵(luan)(luan)(luan)(luan)(luan)量大(da)小也不(bu)同(tong)。取(qu)食(shi)(shi)它喜(xi)歡吃(chi)的(de)蚜蟲(chong)(chong)時,產(chan)卵(luan)(luan)(luan)(luan)(luan)量就(jiu)大(da),取(qu)食(shi)(shi)不(bu)害歡吃(chi)的(de)蚜蟲(chong)(chong)時,產(chan)卵(luan)(luan)(luan)(luan)(luan)量就(jiu)小。
七星瓢蟲(chong)(chong)卵(luan)期長短和溫度有關系,當(dang)16-17℃時,卵(luan)期8天,24-26℃時,卵(luan)期僅(jin)2-3天。七星瓢蟲(chong)(chong)成蟲(chong)(chong)壽命因世代(dai)不(bu)同而有較大差(cha)異。越冬代(dai)成蟲(chong)(chong)壽命一(yi)般都較長,可達8-10個(ge)月,非越冬代(dai)成蟲(chong)(chong)一(yi)般可活2-3個(ge)月。
七(qi)星(xing)瓢蟲(chong)的(de)(de)(de)生殖滯(zhi)育(yu)(yu)突出地表現于2個方面(mian):①種群中(zhong)產(chan)(chan)(chan)卵雌(ci)蟲(chong)所占的(de)(de)(de)比例(li),簡稱(cheng)為產(chan)(chan)(chan)卵率(lv),無(wu)(wu)滯(zhi)育(yu)(yu)時(shi)達100%;如越冬后(hou)蚜蟲(chong)充足時(shi)便(bian)是如此。而其(qi)(qi)第二代則因有生殖滯(zhi)育(yu)(yu),產(chan)(chan)(chan)卵率(lv)下降。②成蟲(chong)羽(yu)化(hua)后(hou)產(chan)(chan)(chan)卵前期延長(chang)的(de)(de)(de)程度(du),這主要(yao)由卵巢發(fa)育(yu)(yu)緩慢或暫時(shi)停頓所造成。顯(xian)示出這種差異的(de)(de)(de)是雌(ci)蟲(chong)。而雄蟲(chong)在滯(zhi)育(yu)(yu)期間其(qi)(qi)行為、趨(qu)性(xing)和(he)生殖附腺的(de)(de)(de)分泌活動雖(sui)與生殖期有所不同,但(dan)仍可交尾,睪(gao)丸(wan)中(zhong)有成熟精(jing)子。雌(ci)蟲(chong)滯(zhi)育(yu)(yu)時(shi)卵巢管停止于原(yuan)卵區階(jie)段,濾泡(pao)不進行發(fa)育(yu)(yu)。這時(shi)咽側體(ti)及其(qi)(qi)細胞體(ti)積(ji)均(jun)小,無(wu)(wu)合(he)成保幼(you)激素(su)的(de)(de)(de)活性(xing)。體(ti)內積(ji)累(lei)較(jiao)多的(de)(de)(de)營(ying)養物質,脂肪體(ti)雖(sui)很發(fa)達,但(dan)不合(he)成卵黃原(yuan)蛋白。
早春田間采集(ji)的(de)(de)越冬(dong)代七星瓢(piao)蟲,因(yin)其發育(yu)階段不同,一般采回飼養1-7天(tian)后(hou)即開始產卵(luan)(luan)(luan)(luan)(luan)。瓢(piao)蟲產卵(luan)(luan)(luan)(luan)(luan)沒(mei)有(you)固定的(de)(de)時間,產卵(luan)(luan)(luan)(luan)(luan)的(de)(de)地點也沒(mei)有(you)嚴格的(de)(de)選擇性(xing),在(zai)盒(he)壁及植(zhi)物上(shang)都可產卵(luan)(luan)(luan)(luan)(luan),為(wei)了集(ji)卵(luan)(luan)(luan)(luan)(luan)的(de)(de)方便,可以裁一長(chang)22厘米、寬5厘米的(de)(de)薄(bo)紙(zhi),卷成紙(zhi)筒,襯在(zai)紙(zhi)盒(he)內(nei)或玻璃器內(nei),使其盡(jin)量(liang)緊貼(tie)在(zai)紙(zhi)盒(he)內(nei)壁,這樣(yang)(yang)卵(luan)(luan)(luan)(luan)(luan)多產在(zai)襯紙(zhi)上(shang)。采卵(luan)(luan)(luan)(luan)(luan)時,可將(jiang)(jiang)襯紙(zhi)取(qu)出,將(jiang)(jiang)有(you)卵(luan)(luan)(luan)(luan)(luan)粒(li)(li)(li)部位的(de)(de)紙(zhi)剪下(xia),放另外的(de)(de)空(kong)紙(zhi)盒(he)中,然后(hou)再(zai)用(yong)紙(zhi)片補(bu)好襯紙(zhi),仍(reng)放盒(he)內(nei)再(zai)用(yong)。取(qu)卵(luan)(luan)(luan)(luan)(luan)時應仔細檢查盒(he)內(nei)植(zhi)物上(shang)有(you)無卵(luan)(luan)(luan)(luan)(luan)粒(li)(li)(li),特(te)別在(zai)氣(qi)候干(gan)燥時,植(zhi)物常(chang)(chang)常(chang)(chang)干(gan)縮,卵(luan)(luan)(luan)(luan)(luan)粒(li)(li)(li)常(chang)(chang)隱藏(zang)其中,如(ru)發現卵(luan)(luan)(luan)(luan)(luan)粒(li)(li)(li),應將(jiang)(jiang)帶有(you)卵(luan)(luan)(luan)(luan)(luan)粒(li)(li)(li)的(de)(de)部位剪下(xia)。如(ru)果用(yong)瓶(ping)養,瓢(piao)蟲卵(luan)(luan)(luan)(luan)(luan)產在(zai)瓶(ping)壁上(shang),取(qu)卵(luan)(luan)(luan)(luan)(luan)時可用(yong)毛筆(bi)沾少(shao)許(xu)清水,將(jiang)(jiang)卵(luan)(luan)(luan)(luan)(luan)濕潤,經數秒(miao)鐘后(hou),再(zai)用(yong)毛筆(bi)尖輕(qing)輕(qing)將(jiang)(jiang)卵(luan)(luan)(luan)(luan)(luan)撥(bo)下(xia),放在(zai)涂有(you)少(shao)許(xu)稀(xi)漿糊的(de)(de)紙(zhi)上(shang),只要(yao)卵(luan)(luan)(luan)(luan)(luan)粒(li)(li)(li)保持(chi)完整,仍(reng)然正常(chang)(chang)孵化。但這樣(yang)(yang)取(qu)卵(luan)(luan)(luan)(luan)(luan),很難保證全部卵(luan)(luan)(luan)(luan)(luan)粒(li)(li)(li)完整無損(sun),且操作(zuo)費時,因(yin)此在(zai)大(da)規(gui)模飼養瓢(piao)蟲寸,仍(reng)以紙(zhi)盒(he)為(wei)宜。
瓢蟲成蟲有取食卵(luan)(luan)粒的(de)習性,產卵(luan)(luan)后,應及時(shi)(shi)將(jiang)卵(luan)(luan)粒取走(zou)。每(mei)日取卵(luan)(luan)的(de)時(shi)(shi)間,可結合(he)兩次(ci)喂食同時(shi)(shi)進行(xing),邊(bian)換飼料、邊(bian)取卵(luan)(luan)。產卵(luan)(luan)高峰期,最(zui)好能每(mei)日取卵(luan)(luan)三次(ci)。
七星瓢(piao)蟲的卵是一(yi)(yi)粒粒豎立成排,形(xing)成整齊的卵塊,由(you)飼養盒(he)中取出(chu)(chu)以后堆放(fang)在(zai)一(yi)(yi)起(qi),很容易彼此摩(mo)擦,影響孵(fu)化(hua)率。七星瓢(piao)蟲的卵在(zai)20℃時(shi)(shi),只需(xu)5-6天即(ji)(ji)可孵(fu)化(hua)。25℃時(shi)(shi)只需(xu)3天即(ji)(ji)可孵(fu)化(hua)。如果長(chang)時(shi)(shi)間堆放(fang)在(zai)一(yi)(yi)起(qi),不(bu)僅(jin)降(jiang)低孵(fu)化(hua)率,而且(qie)幼蟲孵(fu)化(hua)以后,也不(bu)便(bian)于收集(ji)飼養。因此,每次取出(chu)(chu)卵粒以后,應及時(shi)(shi)進行處(chu)理。可通過制(zhi)取卵卡(ka)解決(jue)以上問題。
七(qi)星瓢蟲(chong)的產(chan)(chan)卵(luan)(luan)(luan)期可長達20-30天(tian),產(chan)(chan)卵(luan)(luan)(luan)的高(gao)峰(feng)期亦(yi)(yi)有(you)7-10天(tian),因此(ci),收集的卵(luan)(luan)(luan)塊必(bi)須(xu)立即(ji)進行低(di)溫(wen)(wen)保(bao)(bao)存,以(yi)防(fang)止逐日孵化(hua)(hua)不(bu)便集中使用。加之(zhi)自然氣候(hou)的變化(hua)(hua)或(huo)人工(gong)飼(si)養瓢蟲(chong)的條件改變,都會(hui)造成瓢蟲(chong)的產(chan)(chan)卵(luan)(luan)(luan)高(gao)峰(feng)期、卵(luan)(luan)(luan)的孵化(hua)(hua)期與田間(jian)(jian)蚜蟲(chong)發生的時間(jian)(jian)不(bu)相(xiang)配合,也常需要對(dui)卵(luan)(luan)(luan)做低(di)溫(wen)(wen)保(bao)(bao)存。保(bao)(bao)存的時間(jian)(jian)長短,溫(wen)(wen)度高(gao)低(di)都有(you)一(yi)定的限(xian)度。在(zai)0℃時保(bao)(bao)存3天(tian),其(qi)孵化(hua)(hua)率(lv)(lv)(lv)仍(reng)能達到70%以(yi)上(shang)。超過3天(tian),孵化(hua)(hua)率(lv)(lv)(lv)大為(wei)降低(di)。如在(zai)4℃時,可保(bao)(bao)存7天(tian),孵化(hua)(hua)率(lv)(lv)(lv)在(zai)70%以(yi)上(shang)。在(zai)11-13℃之(zhi)間(jian)(jian),卵(luan)(luan)(luan)可保(bao)(bao)存20天(tian),其(qi)孵化(hua)(hua)率(lv)(lv)(lv)仍(reng)然達到80%左右(you)。實驗(yan)表明(ming),七(qi)星瓢蟲(chong)發育起(qi)點溫(wen)(wen)度為(wei)10℃左右(you),低(di)于這個(ge)溫(wen)(wen)度,瓢蟲(chong)卵(luan)(luan)(luan)雖可短時間(jian)(jian)保(bao)(bao)存,但其(qi)成活率(lv)(lv)(lv)不(bu)高(gao)。如保(bao)(bao)存在(zai)發育起(qi)點溫(wen)(wen)度之(zhi)上(shang),保(bao)(bao)存天(tian)數較長,孵化(hua)(hua)率(lv)(lv)(lv)亦(yi)(yi)高(gao)。因此(ci),卵(luan)(luan)(luan)的保(bao)(bao)存溫(wen)(wen)度以(yi)10-12℃為(wei)宜。
卵(luan)(luan)(luan)的(de)(de)孵(fu)(fu)化(hua)(hua)要求有一定的(de)(de)溫(wen)濕(shi)(shi)(shi)度(du)條件。在(zai)(zai)發(fa)育起點溫(wen)度(du)以上(shang),卵(luan)(luan)(luan)雖然可(ke)以孵(fu)(fu)化(hua)(hua),但(dan)其最適宜的(de)(de)溫(wen)度(du)是20-25℃,相對濕(shi)(shi)(shi)度(du)70-80%。因(yin)(yin)此(ci)在(zai)(zai)卵(luan)(luan)(luan)需要孵(fu)(fu)化(hua)(hua)時(shi)(shi),應(ying)由貯存處取回,放(fang)于室(shi)溫(wen)中進(jin)行。一般在(zai)(zai)棉蚜開(kai)始遷(qian)飛棉田時(shi)(shi),日平均溫(wen)度(du)皆在(zai)(zai)15℃左右(you),均能滿(man)足卵(luan)(luan)(luan)的(de)(de)孵(fu)(fu)化(hua)(hua)溫(wen)度(du)條件,孵(fu)(fu)化(hua)(hua)的(de)(de)關鍵(jian)條件就在(zai)(zai)于濕(shi)(shi)(shi)度(du)。如濕(shi)(shi)(shi)度(du)在(zai)(zai)80%以上(shang),小(xiao)(xiao)幼蟲很容(rong)易由卵(luan)(luan)(luan)殼內孵(fu)(fu)出,但(dan)在(zai)(zai)干燥低濕(shi)(shi)(shi)的(de)(de)條件下,小(xiao)(xiao)幼蟲常(chang)在(zai)(zai)卵(luan)(luan)(luan)口處掙扎,不易脫出。嚴(yan)重時(shi)(shi),甚(shen)至不孵(fu)(fu)化(hua)(hua)。因(yin)(yin)此(ci)大量(liang)的(de)(de)卵(luan)(luan)(luan)需要孵(fu)(fu)化(hua)(hua)時(shi)(shi),應(ying)創造(zao)高濕(shi)(shi)(shi)條件。孵(fu)(fu)化(hua)(hua)時(shi)(shi)可(ke)在(zai)(zai)孵(fu)(fu)化(hua)(hua)室(shi)內地面(mian)潑水,掛濕(shi)(shi)(shi)布(bu)等,增加(jia)室(shi)內濕(shi)(shi)(shi)度(du);亦(yi)可(ke)同(tong)時(shi)(shi)在(zai)(zai)盛(sheng)放(fang)卵(luan)(luan)(luan)卡的(de)(de)容(rong)器內放(fang)濕(shi)(shi)(shi)棉球,容(rong)器頂部再蓋(gai)以濕(shi)(shi)(shi)布(bu),增加(jia)卵(luan)(luan)(luan)卡周(zhou)圍水分的(de)(de)蒸發(fa)條件,經過(guo)這樣處理以后(hou),卵(luan)(luan)(luan)的(de)(de)孵(fu)(fu)化(hua)(hua)時(shi)(shi)間較(jiao)快(kuai),孵(fu)(fu)出后(hou)小(xiao)(xiao)幼蟲生命力較(jiao)強。
卵孵化時(shi),應(ying)加強檢查(cha)與管(guan)理,每日(ri)至少(shao)檢查(cha)4次,發現幼蟲孵出后,應(ying)及時(shi)取出。在卵的孵化高峰(feng)時(shi),應(ying)3-4小(xiao)時(shi)檢查(cha)一次,并(bing)且要求日(ri)夜(ye)有人(ren)看(kan)管(guan)。