中华通草蛉复眼光感受性

运用视网膜电位（Electroretinogram,ERG）技术,对中华通草蛉Chrysopa sinica Tjedar成虫复眼在暗适应过程中对单色光和白光刺激的光感受变化进行了测定。结果表明：（1）在340～605 nm光谱范围内该草蛉的光反应表现3个峰,其中最高峰位于562 nm,次峰在524 nm,第3峰在460 nm;（2）一定光强度（LogI=4.5～0）范围内,其复眼ERG值随光强度的增强而增大,呈近线性增长式样;（3）暗适应时间影响其复眼的ERG值大小,在暗适应100 min时其ERG值达到稳定;（4）中华通草蛉复眼ERG的波形由4个部分组成：开光反应、正相电位、持续负电位和闭光反应。     

光电诱导作用下蝗虫的光谱和光强反应行为研究

目的:研究不同色光和白光刺激下蝗虫成虫和虫蝻的趋光、避光行为反应及其与光强度之间的关系,为蝗虫的光电诱导治理提供理论基础.方法:将蝗虫放置于行为反应试验箱中,运用行为试验方法,观察测定不同光谱和光强下蝗虫的波长选择响应及其运动速度.结果:①蝗虫的趋光、避光反应行为具有相反的波长选择机制,在紫光、蓝光、绿光等短波段趋光性较强,在红光、橙光等长波段趋光性较弱;②低光强度范围内,蝗虫的趋光反应率随光强度的增强而增大,至一定光强度时增加变缓,并趋于稳定;③不同种群、生长阶段对蝗虫的波长、光强度行为反应均有一定影响,东亚飞蝗比亚洲小车蝗有更强的趋光反应率和光强可适应性,成虫比虫蝻的趋光反应率和光强适应性高.结论:光电诱导作用下,蝗虫具有明显的光谱选择行为和光强度行为反应.     

光谱和光强度对西花蓟马雌虫趋光行为的影响

利用行为学方法研究了光谱、光强对西花蓟马Frankliniella occidentalis (Pergande)雌成虫的趋、避光行为的影响。结果显示：（1）在340~605nm波谱内14个波长其光谱趋光行为反应为多峰型,峰间主次较明显。趋光行为反应中,蓝绿区498~524nm有一较宽峰,趋光率20.31%;其它各峰依大小次序分别位于紫光380nm、蓝光440nm;（２）避光行为反应中,蓝光440nm处略高,避光率17.19%;紫外340nm处亦有一峰,避光率15.63%;（３）随光强增强其趋光反应率增大,白光、380nm和524nm刺激时其光强趋光行为反应呈一倒“L”型式样,498nm为峰型,440nm时为一较缓的平直线型;光强最弱时仍均有一定趋光率 ,最强时均未出现高端平台;（４）随光强增强其避光反应率增大,440nm为较平缓直线;340nm刺激时为较缓波动线。结果表明：光谱对其趋光行为有很大影响,光强度的影响较大且影响大小与波长因素有关。     

光谱和光强度对龟纹瓢虫成虫趋光行为的影响

利用行为学方法研究了光谱、光强对龟纹瓢虫Propylea japonica(Thunberg)成虫的趋、避光行为的影响.结果显示:(1)在340～605nm波谱内其光谱趋光行为反应为多峰型,峰间主次不明显,紫外340nm处峰最高,趋光反应率达21%,其它各峰依大小次序分别位于绿光524nm、蓝光400～440nm和483nm处;(2)随光强增强其趋光反应率增大,白光和483nm刺激时其光强趋光行为反应呈一倒"L"型式样,524nm时呈一阶梯型,340nm时为一较平直的线型;光强最弱时仍均有一定趋光率,最强时均未出现高端平台;(3)性别对其光谱和光强度行为反应均有一定影响,但影响不大;(4)龟纹瓢虫无明显的避光反应,其避光行为可能是趋光行为衍生或其随机活动造成.结果表明:光谱对其趋光行为有一定影响,光强度的影响较大且其影响大小与波长因素有关;其复眼可感受的光强范围更宽.     

棉铃虫成虫复眼的光谱敏感性及超极化后电位的研究

采用胞内记录方法研究了雄性棉铃虫小网膜细胞对光刺激的反应特性。结果如下：（１）小网膜细胞对５６２ｎｍ的光最敏感,另外对４００ｎｍ、４８３ｎｍ光也较敏感;（２）对这三种敏感光的光强度反应曲线（Ｖ／ＬｏｇＩｃｕｒｖｅ）与对白光的类似,在一定范围内,随光强度的增加反应增大,呈近似“Ｓ”形曲线;（３）超极化后电位的幅值随闪光刺激强度的增大、刺激时程的延长、对刺激光的敏感程度的增加而增大;（４）感受器的去极化电位与超极化后电位的比值不受刺激强度及光谱的影响,但随闪光刺激时程的延长而逐渐减小。     

大草蛉对桃蚜和夹竹桃蚜的捕食作用研究

大草蛉在我国分布广泛,能捕食多种农作物害虫。本试验首先研究了大草蛉一龄幼虫对桃蚜、大草蛉二龄幼虫对桃蚜和夹竹桃蚜的捕食功能反应。三个反应的最大捕食量Namax分别为144．93、303．03和151．51（头）,瞬时攻击率a分别为0．7428、0．8654和0．6644。大草蛉一龄幼虫有较强的种内干扰反应,随着捕食者密度的增加,捕食作用率（E）依次为0．2025、0．1185、0．0866、0．0694和0．0584;对桃蚜的捕食作用率（E）与自身密度（P）的函数关系式为E=0．2025P^-0.7727。在桃蚜和夹竹桃蚜的混合种群中,大草蛉二龄幼虫对桃蚜的选择效应大于夹竹桃蚜。     

棉铃虫蛾复眼光反应特性

用视网膜电位图(electroretinogram,ERG)技术研究了棉铃虫Helicoverpa armigera蛾暗适应过程中对单色光和白光刺激的光感受性变化。结果显示：(1)依ERG振幅大小(峰-峰值),在340～605 nm波谱内有3个大小不等的峰-主峰位于绿 黄光区562 nm,次峰在蓝光区483 nm,第3个峰在近紫外区400 nm,显示其至少有3种感受器;(2)性别、日龄及暗适应时间长短对其光谱敏感性有影响,低龄时雄蛾对单色光刺激较雌蛾敏感,高日龄时相反;1～5日龄内, 3日龄蛾的视网膜电位(ERP)值最高;随暗适应时间延长,其复眼对近紫外区400 nm敏感性明显增加;(3)一定光强度范围内,随单色光和白光光强度增强该蛾复眼的ERP值增大,初期增加较缓,中期较快,呈近似S型曲线,显示其复眼具有较强的光强度自调节和适应机制。     

光谱和光强度对棕榈蓟马雌成虫行为反应的影响

室内研究了光谱、光强度对棕榈蓟马雌成虫的趋、避光行为的影响。结果显示:在340—605 nm波谱内棕榈蓟马雌成虫对14个单色光刺激的趋光行为反应为多峰型。其中蓝光483 nm处峰最高,趋光反应率达34.96%,其次为绿光498—524 nm、562—582 nm、紫外光340 nm处;其避光行为反应共有3个峰,其中紫外光380 nm处最高,避光率18.08%,另外2个峰分别在橙光605 nm、紫光420 nm处。在趋光率较高的单色光(340、483、524、582 nm)和避光率较高的单色光(380、605 nm)以及白光刺激下,棕榈蓟马雌成虫的趋光率随光强增强的增强而提高,而避光率则随着光强的增强而降低;光强最弱时仍均有一定趋光率,最强时均未出现高端平台。因此:棕榈蓟马雌成虫对不同单色光具有明显的选择性,光谱和光强度对其趋光行为和避光行为有较大影响,光强度的影响作用与波长因素有关。     

棉铃虫[Helicoverpa armigera(Hübner)]蛾复眼视网膜电位研究

运用视网膜电位（Ｅｌｅｃｔｒｏｒｅｔｉｎｏｇｒａｍ , ＥＲＧ） 技术研究了棉铃虫［ Ｈｅｌｉｃｏｖｅｒｐａ ａｒｍｉｇｅｒａ（Ｈüｂｎｅｒ）］ 成虫在暗适应过程中对单色光和复合光（ 即白光） 刺激的光感受性变化, 并初步分析了ＥＲＧ 的波形成分组成及影响因素。结果显示：（１） 依ＥＲＧ 振幅大小（ 峰－ 峰值） ,棉铃虫蛾的光谱敏感曲线在３４０ － ６０５ｎｍ 波谱内有三个大小不等的峰,其中第一峰位于绿－ 黄光区的５６２ｎｍ ,第二峰位于蓝光区的４８３ｎｍ ,第三个峰在近紫外区的４００ｎｍ ,显示其复眼至少具有三种感受器类型。（２） 一定光强度范围内, 一定日龄的棉铃虫蛾的ＥＲＧ 值随单色光和白光刺激光强度的增强而增大, 至一定光强度时增加变缓,呈近似Ｓ 型曲线式样。表明该蛾复眼具有较强的光强度自调节和适应机制。（３） 棉铃虫蛾复眼的ＥＲＧ 波形成分由４ 个部分组成：开光反应、正相电位、持续负电位和闭光反应,波长、光强度及光刺激时程对其各成分有不同影响。     

两种草蛉对取食棉花的扶桑绵粉蚧的嗅觉反应（英文）

捕食性的普通草蛉Chrysoperla sp.（carnea group） 和安平草蛉Mallada desjardinsi（Navas）（脉翅目:草蛉科）的寄主-生境定位取决于其觅食行为以及对各阶段释放的植物气味的行为反应.本研究调查了这两种交配的草蛉成虫以及取食棉花的扶桑绵粉蚧Phenacoccus solenopsis的反应,以便了解它们之间的三重营养关系.结果表明：草蛉雄虫和雌虫均能感受到棉花植株释放的绿叶挥发物;植株的各个阶段均可使捕食性昆虫和绵粉蚧定位.在受绵粉蚧为害的棉叶上饱和烃含量高,说明草蛉成虫的反应更为强烈;在植株受为害期和开花期释放捕食性昆虫,可提高田间捕食性昆虫的作用.这些结果提示有效的生物防治取决于捕食性昆虫在植株上的天然定殖能力以及对害虫的吞食能力.     

铜绿丽金龟对圆偏振光的行为和视网膜电位反应

圆偏振光在地球环境中是很少见的, 来自珠宝金龟甲体壁反射圆偏振光是稀有的自然资源之一。铜绿丽金龟Anomala corpulenta Motschulsky与其他珠宝金龟甲一样其体壁能够反射左旋圆偏振光。为了解铜绿丽金龟对圆偏振光的感知能力, 本研究利用室内行为、 田间诱集与视网膜电位(electroretinogram, ERG)等方法研究了铜绿丽金龟对圆偏振光的响应。室内行为研究结果表明, 铜绿丽金龟对左旋圆偏振光与右旋圆偏振光的趋光反应明显低于非偏振光, 避光反应明显大于非偏振光, 且对左旋圆偏振光的趋、 避光反应均大于右旋圆偏振光。田间选择试验结果显示, 铜绿丽金龟对左旋和右旋圆偏振光的选择明显低于非偏振光, 且右旋大于左旋圆偏振光。电生理学研究结果表明, 左旋和右旋圆偏振光与非偏振光一样, 均能引发铜绿丽金龟的ERG反应, 且无明显差异。这些研究结果表明铜绿丽金龟体壁能够反射产生左旋圆偏振光, 且能够感知和区分左旋和右旋圆偏振光, 说明铜绿丽金龟存在偏振视觉, 具有圆偏振光敏感性。     

铜绿丽金龟对不同光谱的行为反应

【目的】旨在获得铜绿丽金龟 Anomala corpulenta Motschulsky敏感的波谱范围及性别差异。【方法】本研究利用室内行为学的方法,测试了在波长为340~610 nm的14个单色光刺激下铜绿丽金龟的趋、避光行为反应,并计算趋、避光反应率曲线。【结果】观测显示,各单色光均能引起铜绿丽金龟产生一定的趋、避光反应,其雌雄虫的趋光敏感光区位于紫外光（405 nm）、蓝光（460 nm）和绿光区（505和570 nm）,性别对趋光行为有一定的影响,但是仅存在于趋光反应率曲线波峰的大小,而对波峰的位置没有影响。铜绿丽金龟的避光行为反应,在雌雄之间无明显的性别分化,其避光敏感光谱为紫外光（380 nm）、蓝光（440 nm）和绿光区（492和505 nm）。【结论】铜绿丽金龟成虫对不同波长光的趋性存在差异,性别对其光谱行为反应有一定的影响。该研究结果为铜绿丽金龟光视觉的深入研究奠定必要的理论基础,也为利用其趋光性对该金龟甲进行综合治理提供科学依据。     

光谱对东亚小花蝽趋光行为的影响

利用行为学方法研究了340—605nm波谱内14个单色光对东亚小花蝽Orius sauteri(Poppius)成虫的趋、避光行为的影响。结果显示:(1)各单色光均能引起东亚小花蝽成虫趋光行为反应,雌、雄虫的趋光行为反应曲线均为多峰型,峰间主次明显。趋光行为反应率较高的区域有3个,分别是紫外区(340、360 nm和380 nm)、绿光区(524 nm)和橙红光区(582 nm雄虫此处不高、605 nm);(2)各单色光都能引起东亚小花蝽成虫避光行为反应,雌虫避光行为反应曲线为多峰型,避光行为反应率最高的区域为蓝光近紫外区(400 nm),雄虫避光行为曲线为波浪形,避光行为反应率最高的区域为蓝光区(483 nm)。(3)性别对趋光行为反应趋势影响不大,但对趋、避光反应率有较大影响。雌虫趋光反应率最高为47.50%(380 nm),雄虫最高为35.00%(360 nm);雌虫避反应率最高为19.17%(400 nm),雄虫避光反应率最高为11.25%(483 nm)。结果表明:光谱对其趋光行为有一定影响,不同波长之间有较大差异;性别对其光谱行为反应有较大影响。     

Phototactic behaviour of Pachyneuron aphidis (Hymenoptera: Pteromalidae) – hyperparasitoid of Myzus persicae (Hemiptera: Aphidiae)

We investigated the spectral sensitivity and response to light intensity of Pachyneuron aphidis (Hymenoptera: Pteromalidae), which is a common hyperparasitoid of Aphidius gifuensis (Hymenoptera: Braconidae), a key natural enemy of the green peach aphid, Myzus persicae (Hemiptera: Aphididae). To do so, we used 15 monochromatic lights (emitting various specific wavelengths from 340 to 649 nm) and white light. P. aphidis adults are diurnal insects that show a positive phototaxis to a broad spectrum of light. Significant differences were found between sexes in the phototactic responses of P. aphidis to different monochromatic lights. Female P. aphidis showed four peaks of sensitivity at 380, 450, 504 and 589 nm. Male P. aphidis show two peaks of sensitivity, one at 450 nm and second at 628 nm. P. aphidis adults showed an increased phototactic response at low intensities and a decreased phototactic response at high intensities for both UV light and blue light. This experiment will help provide a scientific basis for the development of colour traps for insect pest management.     

Phototaxis by the Dinoflagellate Gymnodinium splendens Lebour*

A microscope-television system was used to monitor quantitatively the behavior of Gymnodinium splendens Lebour in response to light. The predominant behavioral sequence upon stimulation is (a) an initial 2–5 sec cessation of movement (stop-response) followed by (b) positive phototaxis. The action spectra for each response are identical, having maxima at 450 and 280 nm. Upon measuring the percent response to a range of stimulus intensities, it is apparent that a stop-response is not a behavioral prerequisite for phototaxis. An identical circadian rhythm in photoresponsiveness is observed for phototaxis and for the stop-response with greatest light sensitivity occurring during the first 4 hr of the entrained light period. The implication of phototactic sensitivity and the phototactic circadian rhythm in diurnal vertical migration is discussed.     

How 5000 independent rowers coordinate their strokes in order to row into the sunlight: Phototaxis in the multicellular green alga <Emphasis Type="Italic">Volvox</Emphasis>

Background

The evolution of multicellular motile organisms from unicellular ancestors required the utilization of previously evolved tactic behavior in a multicellular context. Volvocine green algae are uniquely suited for studying tactic responses during the transition to multicellularity because they range in complexity from unicellular to multicellular genera. Phototactic responses are essential for these flagellates because they need to orientate themselves to receive sufficient light for photosynthesis, but how does a multicellular organism accomplish phototaxis without any known direct communication among cells? Several aspects of the photoresponse have previously been analyzed in volvocine algae, particularly in the unicellular alga Chlamydomonas.

Results

In this study, the phototactic behavior in the spheroidal, multicellular volvocine green alga Volvox rousseletii (Volvocales, Chlorophyta) was analyzed. In response to light stimuli, not only did the flagella waveform and beat frequency change, but the effective stroke was reversed. Moreover, there was a photoresponse gradient from the anterior to the posterior pole of the spheroid, and only cells of the anterior hemisphere showed an effective response. The latter caused a reverse of the fluid flow that was confined to the anterior hemisphere. The responsiveness to light is consistent with an anterior-to-posterior size gradient of eyespots. At the posterior pole, the eyespots are tiny or absent, making the corresponding cells appear to be blind. Pulsed light stimulation of an immobilized spheroid was used to simulate the light fluctuation experienced by a rotating spheroid during phototaxis. The results demonstrated that in free-swimming spheroids, only those cells of the anterior hemisphere that face toward the light source reverse the beating direction in the presence of illumination; this behavior results in phototactic turning. Moreover, positive phototaxis is facilitated by gravitational forces. Under our conditions, V. rousseletii spheroids showed no negative phototaxis.

Conclusions

On the basis of our results, we developed a mechanistic model that predicts the phototactic behavior in V. rousseletii. The model involves photoresponses, periodically changing light conditions, morphological polarity, rotation of the spheroid, two modes of flagellar beating, and the impact of gravity. Our results also indicate how recently evolved multicellular organisms adapted the phototactic capabilities of their unicellular ancestors to multicellular life.

     

Phototactic Responses of Cell Population to Repeated Pulses of Yellow Light in a Phytoflagellate Cryptomonas sp

Positive phototaxis in cell populations of a phytoflagellate Cryptomonas sp. was recorded photoelectrically when the duration and intensity of repeated pulses of monochromatic yellow light (570 nm) interspersed with darkness were varied. Irrespective of the duration of the light pulses, phototactic responses to repeated pulses were as great as those to continuous irradiation and were linearly dependent on the logarithm of total incident light energy when the dark interval was shorter than 60 milliseconds. Under these conditions, reciprocity between duration and intensity held well. In contrast, when the dark interval exceeded 250 milliseconds, the responses were remarkably reduced regardless of light duration and were not affected by increasing the intensity of actinic light pulses.

The present results clearly indicate that continuous stimulation with actinic light is not essential for the maximum effect, but that the length of dark interval is crucial in phototactic response.

     

Characterization of the Eyespot Regions of "Blind"Chlamydomonas Mutants after Restoration of Photophobic Responses

Chlamydomonas reinhardtii exhibits photophobic and positive and negative phototactic responses that can be defined for cell populations using computerized cell tracking and motion analysis. Mutants CC-2359 and FN68 are pigment deficient mutants that are blocked in carotenoid synthesis and lack these photo responses. In particular, neither mutant exhibits flash-induced photophobic responses to visible light stimuli to which wild-type gametic cells exhibit a strong response, with several behavioral stages. Upon addition of all-trans retinal to these mutants, the photophobic responses are restored with minor quantitative differences from wild-type populations. Using both light and electron microscopy, we have compared the ultrastructural characteristics of wild-type C. reinhardtii to those of both mutants. As previously described, wild-type cells contain an eyespot consisting of 2–4 layers of pigmented granules encased within thylakoid membranes, located between the distal extremities of the flagellar root. This structure is also visible as an orange-red spot in light microscopy. The photoreceptor is thought to be concentrated in the plasma membrane above the eyespot. The mutant, CC-2359, lacks this eyespot as seen by both light and electron microscopy, even when the photophobic response has been restored. FN68-like mutants studied earlier by Morel-Laurens and Feinlieb and others contain an eyespot which can be seen only by electron microscopy. In FN-68, the eyespot generally has the same dimensions as in wt cells, differing mainly in pigment granule appearance. Consistent with these findings, several laboratories have shown that the full range of phototactic responses can be reconstituted in FN68 and CC-2359, but that negative phototaxis requires a significantly stronger light stimulus in the latter strain. We confirm the suggestion that the eyespot is not necessary for the photophobic response, and is not critical for the appropriate assembly and function of the photophobic response receptor in the membrane. Furthermore, the locus of reconstitution of the functional receptor is not the eyespot. Because of the definitive demonstration of the absence of the eyespot in CC-2359, however, the eyespot may play a role in negative phototaxis.     

Ciliary behavior of a negatively phototactic Chlamydomonas reinhardtii

With an instrument that can record the motion of both cilia of the unicellular alga Chlamydomonas reinhardtii for many hours, the behavioral differences of its two cilia have been studied to determine their specific role in phototaxis. The organism was held on a fixed micropipette with the plane of ciliary beating rotated into the imaging plane of a quadrant photodetector. The responses to square-wave light patterns of a wide range of temporal frequencies were used to characterize the responses of each cilium. Eighty-one cells were examined showing an unexpectedly diverse range of responses. Plausible common signals for the linear and nonlinear signals from the cell body are suggested. Three independent ciliary measures--the beat frequency, stroke velocity, and phasing of the two cilia--have been identified. The cell body communicates to the cilia the direction of phototaxis the cell desires to go, the absolute light intensity, and the appropriate graded transient response for tracking the light source. The complexity revealed by each measure of the ciliary response indicates many independent variables are involved in the net phototactic response. In spite of their morphological similarity, the two cilia of Chlamydomonas respond uniquely. Probably the signals from the cell body fan out to independent pathways in the cilia. Each cilium modifies the input in its own way. The change in the pattern of the effective and recovery strokes of each cilium associated with negative phototaxis has been demonstrated and its involvement in phototactic turning is described.