芦毒蛾蛹、卵期的发育起点温度和有效积温的测定及应用

<正> 芦毒蛾Laelia coenosa candida Leech是危害获、芦苇的暴食性叶面害虫。此虫1年发生3代,以幼虫啃食获、芦苇叶片。为了及时准确地作好预测预报,我们对该虫蛹,卵期的发育起点温和有效积温常数进行了测定,经1990年和1991年两年验证,预测的结果与实际发生期基本相符。     

三化螟发生期近期预测误差原因探讨

<正> 根据田间三化螟幼虫的化蛹率,参考天气预报,加相应温度下的蛹历期,预测发蛾期,是目前三化螟发生期近期预测的常用方法。在本地,除幼虫滞育比例很高的第三代以外,对其他世代发蛾期的预测都适用。但据我站1965-1980年田间幼虫化蛹高峰期和实际发蛾高峰期资料检验,这一方法的预测结果,比实际发蛾高峰期显著偏迟。检验方法是以剥查化蛹高峰     

马尾松毛虫幼虫发生高峰期的三种预测模型

【目的】为了科学确定马尾松毛虫Dendrolimus punctatus防治适期,提高防治效果。【方法】采用平稳时间序列法、马尔科夫链法和BP神经网络法研究安徽省潜山县1983-2014年马尾松毛虫幼虫发生的高峰期预测模型,并用2015年和2016年发生资料进行验证。【结果】显示:平稳时间序列法、马尔科夫链法、BP神经网络法模型预测2015年和2016年1代幼虫高峰期均为6月5日,2代高峰期均为9月6日,两年的1、2代实际发生期也是6月5日和9月6日,预测值与实际值完全一致。平稳时间序列法预测1代幼虫高峰期结果,若以大于2 d为误差标准,则1983-2014年的历史符合率为96.77%;若以小于和等于1 d为误差标准,历史符合率为74.19%,2代幼虫高峰的预测结果的历史符合率与1代相同。BP神经网络法预测结果若以1 d为误差标准,1983-2014年则1、2代预测结果的历史符合率均为100%。【结论】在3种方法中,平稳时间序列法适用于害虫发生过程符合平稳时间序列的情况;马尔科夫链法预报量的分级标准科学与否直接影响预测结果的准确性;BP神经网络法可用于自变量与预报量非线性关系的研究,是一种比较理想的预报方法。     

甘蓝夜蛾发育起点温度和有效积温常数的研究

作者1989～1990年利用回归直线法对变温条件下甘蓝夜蛾各虫态发育起点温度和有效积温常数进行了研究,井与实际发生情况作了初步验证。测定结果各虫态发育起点温度卵<幼虫<蛹<雌虫产卵前期,并提出了防治适期的预测式。     

基于外部形态特征量化分析判别菱角水螟幼虫龄期

【目的】本实验拟为田间准确快速判别菱角水螟Parapoynx crisonalis(Walker)幼虫龄期提供一种新方法,以便监测其发生规律、预测其发生时间。【方法】本研究通过对幼虫头壳宽、复眼距、体宽和体长4项外部形态指标的测量,运用Crosby生长法则和线性回归分析方法,结合各项指标的频次分布进行分析。【结果】各龄幼虫头壳宽平均值的变异系数和Crosby指数最小,为判别幼虫龄期的最佳分龄指标,幼虫期共分为5龄,1~5龄的头壳宽分别为(0.2493±0.0053)、(0.3454±0.0018)、(0.5079±0.0031)、(0.7419±0.0190)和(1.1287±0.0369)mm,其与龄期数呈线性关系。通过实验室饲养观察菱角水螟幼虫蜕皮次数验证该虫幼虫期分为5个龄期。【结论】头壳宽为判定菱角水螟幼虫龄期的最佳指标,复眼距次之。     

荔枝蒂蛀虫幼虫龄数及各发育阶段在不同温度下的发育历期

【目的】荔枝蒂蛀虫 Conopomorpha sinensis Bradley是荔枝龙眼上的主要害虫,以幼虫蛀果为害。本研究旨在明确荔枝蒂蛀虫幼虫龄数及不同温度下各虫态和各龄幼虫的发育历期,为该虫发生规律、预测预报和防控技术研究提供基础生物学数据。【方法】定期收集处于不同发育时期的荔枝蒂蛀虫幼虫,测量幼虫头壳宽度,对其进行频次分析,Crosby指数验证和曲线回归分析,以确定幼虫龄数。通过室内群体饲养的方法,测定了17~38℃区间8个温度梯度下荔枝蒂蛀虫各虫态和各龄幼虫的发育历期,并采用线性日度模型对其发育速率与温度的关系进行回归分析。【结果】根据荔枝蒂蛀虫幼虫头壳宽度频次分布图,其头壳宽度的频次分布可明显分为5个区域,说明其幼虫分5个龄期,符合Dyar定律。1-5龄幼虫的头壳宽度分别为：0.092~0.120, 0.140~0.206, 0.217~0.319, 0.356~0.523和0.582~0.728 mm。温度对荔枝蒂蛀虫卵、各龄幼虫和蛹的发育历期有明显影响,其发育历期均随温度的升高而缩短,其发育速率均与温度呈显著正相关,并符合线性回归模型。在20~32℃,荔枝蒂蛀虫可完成世代发育;在17℃时,该虫只能发育至3龄幼虫;在35℃时,蛹多不能羽化;在38℃时,卵多不能孵化。在20~32℃,其世代历期为41.16~19.34 d,蛹期为12.74~5.38 d,而产卵前期为4.75~4.22 d,温度对产卵前期无明显影响。在20~35℃,荔枝蒂蛀虫幼虫可正常发育,其1龄幼虫龄期为4.50~1.17 d,2龄幼虫期为2.09~1.40 d,3龄幼虫期为2.84~1.00 d,4龄幼虫期为3.41~1.18 d,5龄幼虫期为3.00~1.37 d,预蛹期为2.41~0.69 d。在17~35℃,荔枝蒂蛀虫卵可正常孵化,其卵期为7.73~2.09 d。【结论】荔枝蒂蛀虫幼虫分5个龄期,不同于前人所报道的4个龄期。在20~32℃温度范围内,卵、各龄幼虫和蛹的发育历期均随温度升高而缩短。本研究结果有助于荔枝蒂蛀虫预测预报方案的制定和实施。     

茶黑毒蛾的发生规律与预测预报

2010-2012年对云南省普洱市茶黑毒蛾Dasychira baibarana Matsumura的发生规律开展了系统调查,结果表明, 茶黑毒蛾在云南普洱市一年发生5代, 6-10月为茶黑毒蛾幼虫的发生高峰期,3-4代为主害代。茶黑毒蛾幼虫历期以第1代最长,平均33-34 d,其次是第5代,平均为26 d。第2、3、4代幼虫历期为20-21 d。7-9月为茶黑毒蛾成虫的主要发生期。此外, 研究发现, 根据茶园茶黑毒蛾的发蛾高峰日,采用历期法预测防治时期基本可行,可按照预测的时间进行防治或适当提前进行防治。      

茶毛虫各龄幼虫的发育起点温度和有效积温

在16～26℃范围内5个恒温下的饲养结果表明,茶毛虫EuproctispseudoconspersaStrand1～7龄幼虫和整个幼虫期的发育起点温度分别为4.57,8.38,7.00,8.86,7.10,4.84,3.80,6.05℃,有效积温分别为114.45,80.94,91.28,82.23,94.54,117.83,129.46,722.95日·度。用这些结果分龄预测茶毛虫防治适期和茶毛虫病毒室内大量繁殖中幼虫的饲毒日期,与实际情况基本相符。     

旋毛虫丝氨酸蛋白酶基因的结构与功能分析

目的：运用生物信息学原理,对由旋毛虫新生幼虫（NBL）差减文库调取的新生幼虫期特异性基因进行分析。方法：通过对BLASTn核酸数据库及BLASTp蛋白数据库的相似性检索,登陆PROSITE数据库进行蛋白位点和序列模式分析,并采用AN-THEPROT4.3软件包对其理化特性进行分析。结果：相似性检索及序列模式分析显示,该基因为胰蛋白酶家族丝氨酸蛋白酶的编码基因,并对其编码蛋白的理化特性,疏水性,抗原性,信号肽及其二级结构进行了预测,登陆SWISS-MODEL自动蛋白质同源建模服务器,搜索,优化后预测了其3D结构模型。结论：该期特异性基因为旋毛虫新生幼虫胰蛋白酶家族丝氨酸蛋白酶的编码基因。     

冀西北农牧交错区草地螟寄生蜂及其控害作用

【目的】寄生蜂是草地螟Loxostege sticticalis L.卵期和幼虫期的重要天敌,但冀西北地区的发生种类、控害作用尚不明确。【方法】通过1997年以来历年田间调查,结合多年室内饲养。【结果】明确了当地草地螟寄生蜂共14种,其中卵期1种,幼虫期13种,1~5龄幼虫各龄期均有不同种寄生蜂寄生,寄生蜂种类多,种群数量大,寄生率高,控害和压低草地螟种群作用显著。【结论】该调查研究为开展草地螟预测预报,保护利用天敌资源和综合治理提供了科学依据。     

In vitro rearing of the screwworm fly Wohlfahrtia magnifica

Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae) is the main agent of traumatic myiasis in many European, African and Asian countries. Although it can be reared in vivo without technical difficulty, such rearing presents ethical problems. Studies were therefore made of in vitro rearing to facilitate development of laboratory colonies that could be used in a wide range of biological, physiological and applied studies of W. magnifica, particularly in the long period of the year when natural populations of the fly are unavailable for study. Parental colonies of W. magnifica were established from larvae collected from natural infestations of sheep and cattle in central Hungary. First stage larvae were harvested from gravid females and were reared in groups of 5-20 on one of six artificial diets. The diets were based on various combinations of five to seven of eight ingredients: water, agar, blood (heparinized or dried), ground meat, egg yolk, low-fat milk powder, yeast and 10% formol. The larvae were incubated on the diets at 37 degrees C. There was no mortality of first stage larvae, which appeared to feed together in foci, in a natural manner. However, during the second stage, and especially after renewal of diet associated with disturbance of the larvae, many larvae began to disperse, crawling over the surface of the media and feeding less intensively. Mortality of larvae during all larval stadia was 64-98%, compared to 33% in batches of third stage larvae collected from natural infestations. The mean weights of puparia from artificial diets ranged from 38.7 to 59.3 mg, compared to 92.2 mg of puparia from larvae collected from natural infestations. There was a high mortality in the pupal stage, from 61 to 100%. Only a maximum of 6% of first stage larvae were successfully reared to the adult stage. Further studies are needed to identify factors present or absent in the diets that contributed to the present poor development of W. magnifica in vitro.     

Defection by plants in the yucca–yucca moth association: a test of the cheater plant hypothesis for Yucca treculeana

In mutualisms, an underlying conflict of interests may select for defection from providing benefits. In the obligate mutualism between yuccas and yucca moths, where pollination service and seeds for pollinator larvae are traded, it has been suggested that some individuals in a population of Y. baccata may defect by preventing pollinator egg or larvae from development. We tested this hypothesis in Y. treculeana , another species suggested to contain cheater plants. Five specific predictions were tested during two years of study. A prediction that a surplus of plants without pollinator larvae should be present was met. Predicted existence of two distinct fruit morphs was rejected, and none of several highly variable morphological traits were linked to presence/absence of larvae. Predicted excess of intact seeds in the fruits of plants without larvae was not found; in fact, such plants produced fewer seeds, contrary to the hypothesis. A suggestion that inverse frequency-dependent fitness could explain the pattern was rejected. Contrary to prediction, distribution of larvae of a closely related cheater yucca moth was positively associated with pollinator larvae, even though it would not be affected by the proposed killing mechanism. The results together provide strong support against the existence of cheater plants in Y. treculeana .     

The bionomics of the free-living larvae and the transmission of Dictyocaulus filaria between lambs in North-East England.

The bionomics of the free-living larvae of Dictyocaulus filaria on pasture, and the transmission of infection between lambs, were studied during different seasons of the year in North-East England. The rate of development of first-stage larvae to the third stage took 4-9 days in late spring and summer, 1 1/2-4 weeks in autumn and 5 1/2-7 weeks in winter. The proportion of first-stage larvae developing to the third stage ranged from 10-28% in autumn and winter, and 2-25% in spring and summer. The rate of mortality of the third-stage larvae was approximately logarithmic in nature, although the survival time was shorter in spring and summer than in autumn and winter. Third stage larvae were able to survive from autumn until the spring of the following year in sufficient numbers to perpetuate transmission but not to cause clinical disease. In a transmission study, the survival of the infective larvae on the experimental plot was poor in summer, but the larval population increased in the autumn and then declined slowly throughout the winter. Infection in the susceptible lambs was related to the level of infection on the herbage increasing in severity from early summer to late autumn. However, those lambs infected in the summer were resistant to the heavy autumn challenge of larvae on pasture.     

Development of Angiostrongylus cantonensis in the lung of Achatina fulica (author's transl)

Twenty-four Achatina fulica from Pai-sha of the Pescardores Islands, where no Angiostrogylus cantonensis has been found in A. fulica(4), were inoculated with the first stage larvae of A cantonensis. One snail was killed every day after 24 days following inoculation. The lung of each snail was separated and examined for larvae under microscope. The same lung was then digested with pepsin. The larvae recovered after pepsin digestion were examined for more detailed morphology. This study confirmed that the first stage larvae of A. cantonensis passed through the respiratory pore to the lung of A. fulica and developed into infectious form (3rd stage larvae) in the lung. The second and third stage larvae were found in the lung on the 7th and 17th day respectively after inoculation. Worm capsules were found in the lung on the 12th day after inoculation and the size of capsule was in proportion to the duration of the infection.     

Weather and the ecology of bursate nematodes

The free-living stages of bursate nematodes are affected in different ways by meteorological factors. The eggs and 1st and 2nd stage larvae live in the feces, and these factors act on them through the feces. The embryo in the egg is protected by the eggshell. The 1st and 2nd stage larvae feed on micro-organisms, and are affected by the species of microorganisms and their metabolic products. The 3rd stage, infective larvae do not feed but leave the feces and migrate onto the vegetation, where they are more directly affected by meteorological factors than the earlier stages. They are partially protected by their sheath. The degree day concept can be used to predict the length of time required for development to the infective stage. Under constant conditions at 100% relative humidity and 20–35° C,Trichostrongylus colubriformis requires 90–115 degree days (temperature times number of days) to reach the infective stage, andHaemonchus contortus requires 95–144 degree days. The great majority of eggs dies within the 1st day after reaching pasture, altho most of them would develop to the infective stage in the laboratory. Only 0.03% ofH. contortus andT. colubriformis eggs placed on pasture were recovered from the vegetation as infective larvae. When larvae ofH. contortus were placed on pasture, 1.6% (about 50 times as many but still only aout 1/30 of their potential) were later recovered. The cause of this die-off is unknown. Two types of potential worm burden prediction must be made-general and specific. The former can be made on the basis of temperature and moisture, but the latter requires information on many modifying factors.Presented at the Eighth International Congress of Biometeorology, 9–14 September 1979. Shefayim, Israel.     

Skeletal morphogenesis in the urodele skull: II. Effect of developmental stage in thyroid hormone-induced remodeling

This study investigates the effect of developmental stage on thyroid hormone (TH)-mediated remodeling in the skeletal tissues of hemidactyliine plethodontid urodeles. Rate of morphogenesis was quantified in 17 metamorphic tissues for three different size-age classes of Eurycea bislineata larvae immersed in a metamorphic dosage of T₄. Extent of morphogenesis after a 3-week immersion was also quantified in these tissues plus four larval ones for the full size range of E. bislineata larvae and for less complete size ranges of E. wilderae, E. longicauda guttolineata, Gyrinophilus porphyriticus, and Pseudotriton ruber larvae. Although all tissues respond more slowly with decreasing size/age, two tissue-specific effects are evident in all species. Larval ossifications are less inducible than metamorphic ossifications, and progressive metamorphic events are more retarded and, in some cases, more prone to abnormal morphogenesis than regressive ones. The first effect agrees with the prediction that tissues that naturally remodel at metamorphosis are more responsive to a metamorphic dosage of TH than those that respond at a larval stage and lower TH. The second effect agrees with the prediction that progressive morphogenesis is more likely to be impaired at small size than regressive morphogenesis, although the frequent discrepancies between individuals of similar size implicate developmental age more than size in this effect. Collectively, these two effects provide only equivocal support for the hypothesis that direct development in plethodontids evolved via precocious TH activity. However, the unexpected transition from ceratobranchial replacement to ceratobranchial shortening in medium-sized larvae suggests that the former pathway requires a longer period of cell specification at low TH. Since ancestral plethodontids appear to have been distinguished by an exceptionally long larval period with exceptionally low TH activity, this developmental prerequisite may in turn be partly responsible for their singular evolution of ceratobranchial replacement. © 1995 Wiley-Liss, Inc.     

Parent–Offspring Conflict over the Transition to Independence in Nicrophorus vespilloides: Parental Chemical Cues and Offspring Begging

In species where parents provide their offspring with food, the offspring must undergo a transition from nutritional dependency to independence. Parent–offspring conflict theory predicts that the optimal timing for this transition will differ between parents and offspring and that the realised timing depends on each party’s ability to control the transition. The burying beetle Nicrophorus vespilloides is an excellent species for studying conflict over the transition to independence; the larvae beg for pre‐digested carrion from their parents until they cease begging around 72 h after hatching. The cessation of begging is not associated with changes in parental behaviour, suggesting that the transition is mostly under offspring control. However, recent work has demonstrated that caring parents express distinct chemical cues that stimulate larval begging, the expression of which varies between breeding and non‐breeding beetles, suggesting that parents might exert control over the transition to independence by altering these cues throughout development. If so, we predict that begging larvae should behave differently towards parental chemical cues from different stages of development and that larvae of different ages should behave similarly towards parental chemical cues from the same stage of development. We found no evidence for either prediction: begging larvae did not behave differently towards parental chemical cues from different stages of development, and larvae of different ages still behaved differently towards parental chemical cues from the same stage of development. Our results provide no support for the hypothesis that parents can control the transition to nutritional independence by altering their chemical profiles.     

Seasonal distribution and duration of the planktonic stage of Dover sole, Solea solea, larvae in the Bay of Biscay: an hypothesis

The possibility of deriving a prediction about the effect of seasonal variations in the duration of the planktonic larval phase on the dispersal of larval Dover sole was investigated. During six cruises, from February to May 1992, the distribution of sole larvae was studied along a 100-km transect, from the offshore spawning grounds to the coastal nurseries of the Bay of Biscay (France). Samples ( n = 189) were collected with a suprabenthic sampler, and vertical profiles of water temperature and salinity were recorded simultaneously. Counts of otolith increments of larval stage 4b (onset of metamorphosis) were used to estimate the duration of the planktonic life. Duration of the larval phase decreases by about 15 days (37%) with water temperature increase (between 8° in February and 11.2° C in May). Sole larvae occur from the coastal area to 100 km offshore. Within the same cruise, no difference in the duration of the planktonic life was observed between the larvae caught in the onshore and the offshore area. In spite of seasonal differences in abundance, the extent and the shape of the larval distributions during the period of study suggest that the seasonal variations in the duration of the planktonic life did not affect the larval distribution.     

Behavioural Correlations May Cause Partial Support for the Risk Allocation Hypothesis in Damselfly Larvae

Prey animals are often confronted with situations that differ in predation risk. According to the risk allocation hypothesis, prey animals should adaptively allocate antipredator behaviour in accordance with the magnitude and frequency of those risk situations. According to the first prediction prey animals should increase foraging in the safe situations and decrease foraging in the dangerous situations as these situations become relatively more dangerous. The second prediction is that with increased time spent in the dangerous situations, progressively more foraging effort is shown in both the dangerous and safe situations, especially in the safer ones. Prey animals may, however, show maladaptive behaviour due to behavioural correlations across risk situations. Here we test for the first time both predictions generated by the risk allocation hypothesis while considering behavioural correlations. We reared larvae of the damselfly Ischnura elegans, from the egg stage, under five rearing risk conditions: (i) in isolation, (ii) in the presence of conspecific larvae, (iii) in the presence of one fish, (iv) in the presence of two fish, and (v) in the presence of two fish for 50% of the time. For each rearing risk condition, we scored their behaviour in the absence and in the presence of fish. In accordance with the first prediction, in the absence of a predator, larvae reared under increasing risk conditions increased their level of foraging. In accordance with the second prediction, in the absence of a predator, larvae that were more frequently exposed to fish during rearing, increased foraging. However, opposite to the predictions from the risk allocation hypothesis, foraging increased both with increasing rearing risk, and with increased predator exposure frequency. The observed positive behavioural correlation of foraging activity across test situations with and without fish, may generate the combination of adaptive patterns in the absence of fish and the maladaptive patterns in the presence of fish. Former studies of the risk allocation hypothesis also found, at best, mixed support, and we hypothesize that behavioural correlations across risk situations, if present, will likely cause partial deviations from model predictions.     

The influence of cooling rate,developmental stage,and the addition of sugar on the cryopreservation of larvae of the pearl oyster Pinctada fucata martensii

This paper examines the effects of cooling rate, developmental stage, and the addition of sugar on the cryopreservation of the larvae of the pearl oyster, Pinctada fucata martensii. The survival rates of frozen-thawed trochophores was 43.1% at a cooling rate of 1.0 degrees C/min. The survival rate of frozen-thawed larvae increased with developmental stage, except for umbo stage larvae, and the late D-shaped larvae showed a survival rate as high as 91%. The addition of sugar (0.2M glucose or sucrose) improved the survival rate of larvae. These results indicate that the preferred cooling rate, developmental stage, and sugar for the cryopreservation of pearl oyster larvae are 1 degrees C/min, late D-shaped larvae and 0.2M glucose or sucrose.