周曉榕,韓鳳陽,昊 翔,龐保平*,楊曉東,張 鵬
(1. 內(nèi)蒙古農(nóng)業(yè)大學(xué)草原昆蟲研究中心,呼和浩特 010019;2. 內(nèi)蒙古草原工作站,呼和浩特 010020)
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變溫和恒溫對沙蔥螢葉甲發(fā)育速率的影響
周曉榕1,韓鳳陽1,昊 翔1,龐保平1*,楊曉東2,張 鵬2
(1. 內(nèi)蒙古農(nóng)業(yè)大學(xué)草原昆蟲研究中心,呼和浩特 010019;2. 內(nèi)蒙古草原工作站,呼和浩特 010020)
沙蔥螢葉甲為近年來在內(nèi)蒙古草原猖獗成災(zāi)的新害蟲,為明確溫度對其發(fā)育速率的影響,分別設(shè)置5個(gè)變溫組合(8/20℃, 11/23℃, 14/26℃, 17/29℃和20/32℃)和6個(gè)恒溫(13℃,17℃,21℃,25℃,29℃和33℃),比較了變溫和恒溫對沙蔥螢葉甲幼蟲和蛹發(fā)育速率的影響。結(jié)果表明,不同變溫組合和恒溫對沙蔥螢葉甲幼蟲和蛹的發(fā)育速率有顯著的影響。發(fā)育歷期隨溫度的升高而縮短,在變溫條件下,1齡幼蟲期、2齡幼蟲期、3齡幼蟲期、總幼蟲期和蛹期分別從最低溫度組合(8/20℃,平均15℃)的11.00,13.44,23.18,46.42和16.89 d,縮短至最高溫度組合(20/32℃,平均27℃)的4.92,4.63,9.17,17.83和5.83 d;在恒溫條件下,13℃下幼蟲不能發(fā)育和存活,1齡幼蟲期、2齡幼蟲期、3齡幼蟲期、總幼蟲期和蛹期分別從17℃的14.50,10.75,20.63,45.50和11.00 d,縮短至33℃的6.10,5.47,10.60,22.17和5.33 d。在變溫條件下,幼蟲和蛹的發(fā)育起點(diǎn)溫度分別為7.44℃和8.48℃,有效積溫分別為344.82日度和113.52日度;在恒溫條件下,幼蟲和蛹的發(fā)育起點(diǎn)溫度分別為0.64℃和5.11℃,有效積溫分別為714.28日度和147.06日度。變溫促進(jìn)了沙蔥螢葉甲幼蟲和蛹的發(fā)育,本研究結(jié)果為沙蔥螢葉甲的預(yù)測預(yù)報(bào)及綜合防控提供了科學(xué)依據(jù)。
沙蔥螢葉甲;變溫;恒溫;發(fā)育速率;發(fā)育起點(diǎn)溫度;有效積溫
昆蟲是變溫動(dòng)物,環(huán)境溫度對其活動(dòng)、分布和多度的影響可能高過任何一種非生物因素(Harrisonetal., 2012)。溫度對昆蟲生長發(fā)育、繁殖、存活及行為的影響一直以來受到人們的高度重視。然而,目前絕大多數(shù)研究都是在恒溫條件下進(jìn)行的,而昆蟲總是生活在溫度變化的環(huán)境條件下,因而對變溫環(huán)境更加適應(yīng)。已有研究表明,在恒溫和變溫條件下,昆蟲在發(fā)育速率(劉樹生,1991;Niedereggeretal., 2010; Baharetal., 2012)、繁殖率和存活率(Fantinouetal., 2003; Fischeretal., 2011; Carringtonetal., 2013; Htweetal., 2013)以及生命表參數(shù)(王海鴻等,2014)等方面存在顯著差異。沙蔥螢葉甲Galerucadaurica(Joannis) 是一種近年來在內(nèi)蒙古草原上猖獗成災(zāi)的新害蟲,從2009 年開始在內(nèi)蒙古草原上突然大面積暴發(fā)成災(zāi),呈現(xiàn)逐年加重的趨勢。然而,目前有關(guān)沙蔥螢葉甲的研究很少,只有馬崇勇等(2012)對該蟲在呼倫貝爾市的發(fā)生為害及生活史進(jìn)行了初步調(diào)查,李浩等(2014)和昊翔等(2014)分別對其抗寒性和寄主植物對其生長發(fā)育及取食進(jìn)行了研究。該蟲發(fā)生區(qū)均處于高緯度、高海拔的草原地區(qū),晝夜溫差大,特別是幼蟲發(fā)生為害的春季,晝夜溫差通常在12℃以上。因此,作者根據(jù)沙蔥螢葉甲主要發(fā)生危害區(qū)—錫林郭勒盟錫林浩特市和阿巴嘎旗草原的實(shí)際晝夜溫度變化,設(shè)計(jì)了一系列變溫組合,比較了變溫和恒溫對該蟲發(fā)育速率的影響,以便為沙蔥螢葉甲的預(yù)測預(yù)報(bào)提供可靠的信息。
1.1 供試蟲源
2014年4月15日從阿巴嘎旗草原采回沙蔥螢葉甲越冬卵,將卵置于溫度25℃±1℃、RH 75%±10%的PRX-350C智能型人工氣候箱(寧波海曙塞福實(shí)驗(yàn)儀器廠)中培養(yǎng),備用。
1.2 試驗(yàn)方法
將當(dāng)天孵化的幼蟲放于指形管(3齡后換入培養(yǎng)皿)中,用濕棉球塞住管口,以保濕和防止幼蟲逃逸。每日定時(shí)更換食物(野韭),同時(shí)觀察記載幼蟲脫皮、死亡情況。使用MGC-300B光照培養(yǎng)箱(上海一恒科學(xué)儀器有限公司)控制溫度,共設(shè)5個(gè)變溫和6個(gè)恒溫處理。變溫:8/20℃(平均15)、11/23℃(18)、14/26℃(21)、17/29℃(24)及20/32℃(27)(每個(gè)變溫組合中高溫光照處理14 h,低溫黑暗處理10 h);恒溫:13℃、17℃、21℃、25℃、29℃和33℃。每個(gè)溫度處理50頭幼蟲。
1.3 數(shù)據(jù)統(tǒng)計(jì)與分析
1.3.1 發(fā)育起點(diǎn)溫度和有效積溫的估計(jì)
根據(jù)發(fā)育速率(V)與溫度(T)的線性關(guān)系擬合直線回歸方程V=a+bT,然后根據(jù)公式C=-a/b和K=1/b,求出沙蔥螢葉甲各齡幼蟲和蛹的發(fā)育起點(diǎn)溫度(C)和有效積溫(K)。
1.3.2 數(shù)據(jù)分析
應(yīng)用DPS 9.5統(tǒng)計(jì)軟件,采用單因素方差分析和LSD多重比較測定不同變溫和恒溫下發(fā)育歷期間的差異顯著性。
2.1 變溫和恒溫條件下沙蔥螢葉甲的發(fā)育歷期
從表1和表2可知,不同變溫和恒溫條件下沙蔥螢葉甲各齡幼蟲和蛹的發(fā)育歷期存在顯著的差異(P< 0.05),發(fā)育歷期隨著溫度的升高而縮短。在各變溫和恒溫條件下,3齡幼蟲發(fā)育歷期均顯著長于1齡或2齡發(fā)育歷期。在變溫條件下,幼蟲期從最低溫度(平均15℃)的43.42 d縮短至最高溫度(平均27℃)的17.83 d,蛹期從16.89 d 縮短至5.83 d。在恒溫條件下,在13℃的低溫條件下幼蟲只發(fā)育到1齡就全部死亡,幼蟲期從較低溫度(17℃)的45.50 d縮短到最高溫度(33℃)的25.25 d。在相同的平均溫度(21℃)下,各齡幼蟲和蛹在變溫下的發(fā)育速率均快于恒溫下的發(fā)育速率,甚至在變溫的平均溫度低于恒溫的情況下,變溫下的發(fā)育速率仍快于恒溫下的發(fā)育速率。說明變溫促進(jìn)了沙蔥螢葉甲幼蟲和蛹的發(fā)育。
表1 在不同變溫條件下沙蔥螢葉甲的發(fā)育歷期(d)
注:表中數(shù)據(jù)為平均數(shù)±標(biāo)準(zhǔn)誤,同行數(shù)據(jù)后不同字母表示差異顯著(P<0.05,LSD法)。下表同。Note: Data are mean±SE, and different letters in the same row indicate significant difference (P<0.05, LSD). As the same to tables below.
表2 在不同恒溫條件下沙蔥螢葉甲的發(fā)育歷期(d)
2.2 變溫和恒溫條件下沙蔥螢葉甲的發(fā)育速率、發(fā)育起點(diǎn)溫度和有效積溫
根據(jù)表1和表2分析結(jié)果,將發(fā)育歷期轉(zhuǎn)換成發(fā)育速率,建立發(fā)育速率與溫度的關(guān)系(圖1和圖2)。結(jié)果表明,在恒溫17℃-33℃和變溫15℃-27℃范圍內(nèi),沙蔥螢葉甲發(fā)育速率與溫度呈顯著的直線關(guān)系。隨著溫度的升高,沙蔥螢葉甲各齡幼蟲和蛹的發(fā)育速率逐漸加快。
根據(jù)發(fā)育速率與溫度的線性關(guān)系,求出沙蔥螢葉甲各齡幼蟲和蛹的發(fā)育起點(diǎn)和有效積溫(表3)。從表3可知,不論是在變溫還是恒溫條件下,各齡幼蟲和蛹的發(fā)育起點(diǎn)溫度和有效積溫均不相同。在變溫條件下,1齡幼蟲的發(fā)育起點(diǎn)溫度最低為5.15℃,2齡幼蟲最高為8.84℃;2齡幼蟲所需的有效積溫最低為81.71日度,3齡幼蟲最高為173.06日度;整個(gè)幼蟲期的發(fā)育起點(diǎn)溫度為7.34℃,所需有效積溫為363.30日度。在17℃-33℃的恒溫范圍內(nèi),3齡幼蟲發(fā)育起點(diǎn)溫度最低為-0.93℃,蛹最高為5.11℃;蛹所需的有效積溫最低為147.06日度,3齡幼蟲最高為370.37日度;整個(gè)幼蟲期的發(fā)育起點(diǎn)溫度為0.64℃,所需有效積溫為714.28日度。上述結(jié)果表明,變溫下得出的發(fā)育起點(diǎn)溫度高于恒溫,而有效積溫是變溫下遠(yuǎn)小于恒溫。
圖1 在不同變溫條件下沙蔥螢葉甲的發(fā)育速率Fig.1 Developmental rates of Galeruca daurica at different fluctuating temperatures
圖2 在不同恒溫條件下沙蔥螢葉甲的發(fā)育速率Fig.2 Developmental rates of Galeruca daurica at different constant temperatures
發(fā)育階段Developmentalstage變溫Fluctuatingtemperature恒溫Constanttemperature發(fā)育起點(diǎn)溫度CDevelopmentalthresholdtemperature有效積溫KEffectiveaccumulatedtemperature決定系數(shù)R2Determinationcoefficient發(fā)育起點(diǎn)溫度CDevelopmentalthresholdtemperature有效積溫KEffectiveaccumulatedtemperature決定系數(shù)R2Determinationcoefficient1齡幼蟲1stinstar5041111109539??2571785709219??2齡幼蟲2ndinstar884819709861??1051785709618??3齡幼蟲3rdinstar7161785709915??-0933703709819??幼蟲Larva7443448209986??0647142809875??蛹Pupa8481135209890??5111470609437??
昆蟲自然種群長期生活于晝夜溫度波動(dòng)的環(huán)境下,經(jīng)過長期的進(jìn)化,昆蟲適應(yīng)了溫度變動(dòng)的環(huán)境條件,適溫范圍內(nèi)的變溫可能更有利于昆蟲的生長發(fā)育。本文結(jié)果表明,變溫促進(jìn)了沙蔥螢葉甲幼蟲和蛹的發(fā)育,發(fā)育速率加快。其他研究者也獲得了相同的結(jié)果,如:波動(dòng)的溫度促進(jìn)了小菜蛾P(guān)lutellaxylostella及其天敵—彎尾姬蜂Diadegmainsulare的生長發(fā)育(Baharetal., 2012),波動(dòng)溫度使麻蠅Sarcophagaargyrostoma和亮綠蠅Lucilliaillustris的發(fā)育加快(Niedereggeretal., 2010),變溫使西花薊馬Frankliniellaoccidentalis卵—蛹的歷期縮短(王海鴻等,2014)。但也有研究表明,與恒溫(13℃)相比,變溫(5-29℃,平均13℃)使紅頭麗蠅Calliphoravicina和黑頰麗蠅C.vomitoria的發(fā)育延長1 d(Niedereggeretal., 2010)。造成研究結(jié)果不同的原因可能與昆蟲種類以及變溫設(shè)置范圍有關(guān),變溫范圍超出了該種昆蟲的適宜范圍就會(huì)對其生長發(fā)育造成不利的影響(Carringtonetal., 2013)。本文設(shè)置變溫的最低溫度為8℃,最高為32℃,變溫處理的平均溫度為15℃-27℃,上述溫度范圍。均為昆蟲生長發(fā)育的適宜溫度范圍,也未超出沙蔥螢葉甲幼蟲和蛹發(fā)生時(shí)的實(shí)際溫度范圍Niederegger等(2010)設(shè)置的最低溫度過低(5℃)不適合紅頭麗蠅和黑頰麗蠅的發(fā)育,可能是造成變溫使兩種麗蠅發(fā)育延長1 d的主要原因。另外,作者沒有進(jìn)行差異顯著性分析,僅相差1 d是否有顯著差異?值得商榷。
溫度與昆蟲生長發(fā)育模型可用于研究溫度對昆蟲發(fā)育速率的影響(時(shí)培建等,2011)。本文根據(jù)有效積溫法則計(jì)算了沙蔥螢葉甲幼蟲和蛹的發(fā)育起點(diǎn)溫度和有效積溫。在變溫條件下,沙蔥螢葉甲幼蟲和蛹的發(fā)育起點(diǎn)溫度分別為7.34℃和8.48℃;而在恒溫條件下,分別為0.64℃和5.11℃。作者實(shí)時(shí)記錄了2014年錫林浩特的氣溫,沙蔥螢葉甲幼蟲孵化高峰期4月下旬至5月上旬的日平均溫度為7.7℃,與變溫下估計(jì)的發(fā)育起點(diǎn)溫度較為吻合,而與恒溫下估計(jì)的發(fā)育起點(diǎn)溫度相差較大。在恒溫條件下,幼蟲在13℃下只發(fā)育到1齡就全部死亡。這說明恒溫條件下的實(shí)驗(yàn)并不能真實(shí)地反映昆蟲發(fā)育與溫度的關(guān)系,根據(jù)有效積溫法則計(jì)算的發(fā)育起點(diǎn)溫度和有效積溫也不適合用于定量預(yù)測(Wuetal., 2014)。
本文比較了變溫和恒溫對沙蔥螢葉甲幼蟲和蛹發(fā)育速率的影響。結(jié)果表明,變溫促進(jìn)了幼蟲和蛹的生長發(fā)育,根據(jù)發(fā)生地實(shí)際溫度波動(dòng)情況設(shè)置的變溫實(shí)驗(yàn)獲得的發(fā)育歷期、發(fā)育起點(diǎn)溫度和有效積溫等信息更符合實(shí)際情況,為沙蔥螢葉甲的預(yù)測預(yù)報(bào)提供了更可靠的信息。但是,由于該蟲1年發(fā)生1代,冬季以卵滯育越冬,成蟲夏季羽化后即進(jìn)入滯育越夏,給研究工作帶來很大的困難,有關(guān)溫度對卵和成蟲生長發(fā)育的影響有待于今后進(jìn)一步研究。
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Effects of alternating and constant temperatures on the developmental rate ofGalerucadaurica(Coleoptera: Chrysomelidae)
ZHOU Xiao-Rong1, HAN Feng-Yang1, HAO Xiang1, PANG Bao-Ping1*, YANG Xiao-Dong2, ZHANG Peng2
(1. Research Center for Grassland Entomology, Inner Mongolia Agricultural University, Hohhot 010019,China; 2. Inner Mongolia Grassland Station, Hohhot 010020,China)
Galerucadaurica(Joannis) is a new pest causing great damages in Inner Mongolia grasslands in recent years. This study aims to understand the effects of alternating and constant temperatures on the individual developmental rate. We compared the influence of five combinations of alternating temperatures (8/20℃, 11/23℃,14/26℃,17/29℃ and 20/32℃) and six constant temperatures (13℃,17℃,21℃,25℃,29℃ and 33℃) on the developmental rates ofG.dauricalarvae and pupae. The results showed that both alternating and constant temperatures affected significantly the developmental rates ofG.dauricalarvae and pupae. The developmental durations of various instar larvae and pupae shortened as the temperature increased. The developmental durations of 1stinstar, 2ndinstar, 3rdinstar, larvae and pupae shortened from 11.00, 13.44, 23.18, 46.42 and 16.89 d at the lowest combination of alternating temperature (8/20℃, average at 15℃) to 4.92, 4.63, 9.17, 17.83 and 5.83 d at the highest combination (20/32℃, average at 27℃), respectively. The larvae could not develop and died in the 1stinstar at constant temperature of 13℃. The developmental durations of 1stinstar, 2ndinstar, 3rdinstar, larvae and pupae shortened from 14.50, 10.75, 20.63, 45.50 and 11.00 d at constant temperature of 17℃ to 6.10, 5.47, 10.60, 22.17 and 5.33 d at 33℃, respectively. At the alternating temperatures, the developmental threshold temperatures of larvae and pupae were 7.44℃ and 8.48℃, respectively, and the effective accumulated temperatures were 344.82 and 113.52 degree-days, respectively. At the constant temperatures, the developmental threshold temperatures of larvae and pupae were 0.64℃ and 5.11℃, respectively, and the effective accumulated temperatures were 714.28 and 147.06 degree-days, respectively. The alternating temperature can promote the development ofG.dauricalarvae and pupae. These results provide a scientific basis for the forecasting and integrated management of this pest.
Galerucadaurica; alternating temperature; constant temperature; developmental rate; developmental threshold temperature; effective accumulated temperature
國家自然科學(xué)基金(31360441)
周曉榕,女,副教授,主要從事昆蟲生態(tài)學(xué)研究,E-mail: rong62722@163.com
*通訊作者Author for correspondence, E-mail: pangbp@imau.edu.cn
Received:2015-09-02;接受日期Accepted:2015-10-07
Q968.1;S433.5
A
1674-0858(2016)05-0931-05