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1.
【目的】本研究旨在明确松墨天牛 Monochamus alteratus 成虫及越冬幼虫体型大小的差异,探讨该虫越冬后成虫体型大小和越冬幼虫体重大小关系及原因。【方法】于2014年5月1日至10月31日在浙江富阳野外诱捕松墨天牛,通过测量野外诱捕到的松墨天牛成虫体长、体宽,确定林间松墨天牛成虫体型的差异;松墨天牛越冬幼虫的采集和称重测量明确越冬幼虫的组成和体重大小差异;进而通过对越冬幼虫单头跟踪饲养至化蛹、羽化,确定越冬幼虫体重大小与发育所得蛹和成虫大小的关系,阐明林间松墨天牛成虫体型差异的原因。【结果】浙江富阳野外诱捕发现,松墨天牛的活动期间很长,从5月中旬到10月初一直能诱捕到松墨天牛成虫,高峰期在6和7月份。松墨天牛雌雄成虫体型差异很大,雌虫平均体长和体宽分别为20.59±0.19和6.59±0.06 mm;雄虫平均体长和体宽分别为19.90±0.26 和6.44±0.08 mm; 雌虫的平均体长明显高于雄虫,但二者体宽没有显著差异;并且雌雄成虫体长和体宽呈显著正相关。越冬幼虫的头宽测定表明头宽的变化很大,最小为2.20 mm,最大为4.24 mm,经比对越冬幼虫由4龄和5龄幼虫组成;幼虫体重差异大,平均体重为304.2 mg, 介于71.6~858.0 mg之间,其中5龄越冬幼虫显著重于4龄越冬幼虫。进一步将越冬幼虫单管饲养跟踪研究发现,越冬幼虫体重大小决定蛹和羽化后的成虫的大小,二者存在显著的正相关,并且由4龄越冬幼虫发育所得的蛹和成虫显著轻于由5龄幼虫发育所得的蛹和成虫。【结论】松墨天牛成虫体型差异很大,这与越冬幼虫体重差异相关;越冬幼虫的体重大小决定了其化蛹后的蛹重和羽化后成虫的体型和体重的大小;造成越冬幼虫体重差异的可能原因包括松墨天牛成虫扬飞周期长导致的产卵期长而使得天牛发育进度不一致以及寄主不同部位营养的差异。  相似文献   

2.
It is often proposed that the morphometric shape of animals often evolves as a correlated response to selection on life-history traits such as whole-body growth and differentiation rates. However, there exists little empirical information on whether selection on rates of growth or differentiation in animals could generate correlated response in morphometric shape beyond that owing to the correlation between these rates and body size. In this study genetic correlations were estimated among growth rate, differentiation rate, and body-size-adjusted head width in the green tree frog, Hyla cinerea. Head width was adjusted for size by using the residuals from log-log regressions of head width on snout-vent length. Size-adjusted head width at metamorphosis was positively genetically correlated with larval period length. Thus, size-independent shape might evolve as a correlated response to selection on a larval life-history trait. Larval growth rate was not significantly genetically correlated with size-adjusted head width. An additional morphometric trait, size-adjusted tibiofibula length, had a nonnormal distribution of breeding values, and so was not included in the analysis of genetic correlations (offspring from one sire had unusually short legs). This result is interesting because, although using genetic covariance matrices to predict long-term multivariate response to selection depends on the assumption that all loci follow a multivariate Gaussian distribution of allelic effects, few data are available on the distribution of breeding values for traits in wild populations. Size at metamorphosis was positively genetically correlated with larval period and larval growth rate. Quickly growing larvae that delay metamorphosis therefore emerge at a large size. The genetic correlation between larval growth rate and juvenile (postmetamorphic) growth rate was near zero. Growth rate may therefore be an example of a fitness-related trait that is free to evolve in one stage of a complex life cycle without pleiotropic constraints on the same trait expressed in the other stage.  相似文献   

3.
人工注射Dnmt3 siRNA对意大利蜜蜂雌蜂发育的影响   总被引:2,自引:0,他引:2  
为了研究人工注射DNA甲基化转移酶3 (DNA methyltransferase3, Dnmt3) siRNA对意大利蜜蜂Apis mellifera ligustica雌蜂的Dnmt3酶活性、 Dnmt3 mRNA表达量、 dynactin p62基因甲基化水平以及蜜蜂形态指标之间的影响和关系, 分别给3组3日龄的意大利蜜蜂幼虫人工注射50 ng Ringer, uth siRNA和Dnmt3 siRNA溶液。在幼虫的发育过程中, 测定每组幼虫头部的Dnmt3酶活性、 Dnmt3 mRNA表达量、 dynactin p62基因甲基化水平以及刚羽化雌性蜜蜂的初生重、 体长、 前翅长、 前翅宽、 吻长、 第3背板长等形态指标。结果表明: 人工注射Dnmt3 siRNA不仅可以显著降低意大利蜜蜂幼虫头部Dnmt3酶活性、 Dnmt3 mRNA表达量和dynactin p62基因整体甲基化水平, 同时显著提高了刚羽化雌性蜜蜂的初生重、 体长、 第3背板长。结果说明Dnmt3的改变可以影响雌性意蜂幼虫的发育。  相似文献   

4.
绿豆象幼虫虫龄的划分及末龄幼虫头部形态和感器观察   总被引:1,自引:0,他引:1  
【目的】明确绿豆象Callosobruchus chinensis幼虫的龄期,了解其末龄幼虫头部感受器的种类、形态和分布。【方法】测量绿豆象幼虫体长、头壳宽和上颚宽,根据所得数据的频次分布图、关系拟合结果和戴氏法则确定绿豆象最佳分龄指标,明确幼虫虫龄数,并利用Crosby生长法则和线性回归的方法进行验证;采用扫描电镜对末龄幼虫头部形态及感受器进行观察。【结果】绿豆象体长、头壳宽和上颚宽的频次分布均呈显著的4个峰,因此推断绿豆象幼虫为4个虫龄。各龄的体长变幅分别为1.581~2.556, 2.406~3.381, 3.381~4.281和4.206~4.881 mm,头壳宽度变幅分别为0.444~0.689, 0.654~0.934, 0.934~1.179和1.144~1.389 mm,上颚宽变幅分别为0.080~0.256, 0.234~0.344, 0.322~0.542和0.542~0.652 mm。体长、头壳宽和上颚宽均符合戴氏法则和Crosby生长法则,并呈现明显的线性关系,因此体长、头壳宽和上颚宽可作为绿豆象幼虫龄期划分的重要指标。头壳宽的Crosby指数均小于体长和上颚宽的Crosby指数,且头壳宽与体长测量值的对数值与幼虫龄期的相关系数要优于上颚宽测量值的对数值与幼虫龄期的相关系数,因此可将头壳宽作为最佳分龄指标。绿豆象末龄幼虫头部感器共有锥形感器、毛形感器、瓶形感器、刺形感器、板形感器、栓锥形感器和坛形感器7种感器,主要分布于触角、下颚须、上唇和上颚。【结论】绿豆象幼虫分龄形态指标和头部形态观察为研究其行为活动及综合防治提供理论基础。  相似文献   

5.
6.
周斌  周国英  杨权  董文统  李小敏  周莎  何苑皞 《昆虫学报》2015,58(11):1253-1261
【目的】棕斑澳黄毒蛾Orvasca subnotata Walker是于降香黄檀Dalbergia odorifera T. Chen人工林中新发现的一种食叶害虫,其生物学特性描述和龄期判定是虫害预测预报与林间防治的重要依据。【方法】本研究通过定期林间采样的方法,对棕斑澳黄毒蛾不同发育阶段的形态特征及生活史和生活习性进行调查; 并通过测量头宽、前胸毛瘤宽和体长3项分龄指标,测定棕斑澳黄毒蛾幼虫的龄期。【结果】本文报道了棕斑澳黄毒蛾不同发育阶段的形态特征、生活史和生活习性。研究结果表明,棕斑澳黄毒蛾幼虫随龄期增长,前胸逐渐变黑,腹部背线和翻缩腺颜色逐渐加深,特征逐渐变得明显。通过频次分析统计,测得棕斑澳黄毒蛾幼虫龄数为5龄。头宽和前胸毛瘤宽可作为分龄指标,头宽优于前胸毛瘤宽,且前胸毛瘤宽与头宽呈直线关系(y=0.994x-0.114,R=0.999)。体长经统计检验,符合Dyar氏法则,但区域重叠明显,不宜作为分龄指标。【结论】本研究确定了棕斑澳黄毒蛾的生物学特性及幼虫虫龄,可为林间防治提供参考依据。  相似文献   

7.
为掌握白蜡外齿茎蜂Stenocephus fraxini幼虫的龄数和发育历期,本文测量了幼虫体长、头宽、体宽(胸部第3节)、尾铗长和尾铗基径宽等5项指标.经频次分布和回归分析,结果表明:白蜡外齿茎蜂幼虫可分5龄.头宽和尾铗基径宽均可作为分龄指标.各龄头宽值分别为:0.414±0.002、0.526±0.002、0.71...  相似文献   

8.
This study investigated the biological effects of various dietary essential fatty acids levels to sea scallop larvae, Placopecten magellanicus. Scallop larvae were fed three diets from D-veliger to settlement. Diet A consisted of Isochrysis sp. and Pavlova lutheri, diet B was a mix of Isochrysis sp. and Chaetoceros muelleri and diet C consisted of the same two species, but C. muelleri was grown under silicate deprivation to alter the fatty acid composition. Pediveligers (28 days old) were sampled prior to settlement for fatty acid analysis, growth measurement and survival assessment. Survival and settlement success were measured at the end of the experiment (day 40). Our results show that feeding regime greatly influenced larval size, settlement and fatty acid composition. Diet A was severely deficient in arachidonic acid (20:4n-6, AA), leading to the poorest larval growth, survival and lipid content. Nevertheless, larvae fed diet A selectively accumulate AA by a factor three compared to the dietary amount. Shell size of 28-day-old larvae was positively correlated with AA content and negatively correlated with eicosapentaenoic acid (20:5n-3, EPA)-AA ratio, thus suggesting that these two variables are of major interest for the optimisation of larval growth in sea scallops. Finally, larvae fed diet C displayed 20% higher shell size at day 28 than larvae fed diet A and B, likely in relation to the dietary amount of saturated fatty acid (SFA). However, the moderate survival and settlement success of these groups of larvae might be associated with a relative deficiency in docosahexaenoic acid (22:6n-3, DHA). This study underlines that the overall balance between polyunsaturated fatty acid (PUFA) needs to be considered to adequately fed sea scallop larvae.  相似文献   

9.
Pseudopimelodidae are Neotropical catfishes characterized by having slightly to strongly depressed body in fully developed specimens. The largest species of the family with 500 mm SL, Lophiosilurus alexandri, experiences impressive changes in body shape during development, becoming extremely depressed when fully developed. Accordingly, Lophiosilurus alexandri is an ideal species to observe the morphological changes during ontogeny, and to seek solid interpretations on the polarity of characters. Specimens of distinct larval periods (yolk sac, flexion and postflexion; n = 186 specimens) and juvenile stages (n = 20) were analyzed. Changes in body shape, position of mouth and eye, morphology of fins and pigmentation were observed during the development of Lophiosilurus. Larvae (5.7–11.2 mm standard length) had pigmentation concentrated on the head and parts of body, eyes small and pigmented, short barbels, and well-developed finfold. Juveniles (15.9–28.1 mm standard length) had body shape similar to adult, with head depressed and bearing bony ridges, large mouth, dorsally-oriented eyes, small barbels and well-developed shoulder bulges (cleithral width). The greatest morphological changes in the development of L. alexandri occurred during the postflexion larval stage. Relative to standard length, measurements of snout length, head depth and body depth are smaller in juveniles than in larvae, but body width is larger. New interpretations on the phylogenetic characters related to these changes are provided in view of the two alternative hypotheses of the evolution of Pseudopimelodidae.  相似文献   

10.
In fish species with alternative male mating tactics, sperm competition typically occurs when small males that are unsuccessful in direct contests steal fertilization opportunities from large dominant males. In the grass goby Zosterisessor ophiocephalus, large territorial males defend and court females from nest sites, while small sneaker males obtain matings by sneaking into nests. Parentage assignment of 688 eggs from 8 different nests sampled in the 2003–2004 breeding season revealed a high level of sperm competition. Fertilization success of territorial males was very high but in all nests sneakers also contributed to the progeny. In territorial males, fertilization success correlated positively with male body size. Gonadal investment was explored in a sample of 126 grass gobies collected during the period 1995–1996 in the same area (61 territorial males and 65 sneakers). Correlation between body weight and testis weight was positive and significant for sneaker males, while correlation was virtually equal to zero in territorial males. That body size in territorial males is correlated with fertilization success but not gonad size suggests that males allocate much more energy into growth and relatively little into sperm production once the needed size to become territorial is attained. The increased paternity of larger territorial males might be due to a more effective defense of the nest in comparison with smaller territorial males.  相似文献   

11.
The incidence of superparasitism in field populations of Diachasmimorpha longicaudata (Ashmead), a solitary larval–pupal endoparasitoid, attacking Anastrepha fruit fly species was determined. From 14,550 fruit fly larvae infesting mango fruits in the field, 68.9% (10,038) survived to the pupal stage. Of these pupae, 3780 (37.7%) were parasitized, of which 2075 (54.9%) were superparasitized. The number of oviposition scars per pupa ranged between 1 and 29, although high numbers were rare. The presence of one or two scars per host was frequent, but only 8.6% of pupae had more than three scars. Fruit size was positively related to the level of infestation by Anastrepha spp. and was significantly correlated with the numbers of parasitized and superparasitized pupae by D. longicaudata. The length and width of host pupae were positively related to superparasitism, and superparasitism was positively correlated with a sex ratio biased toward females. Our data show that superparasitism is present in natural populations of D. longicaudata at remarkable rates and confers some advantageous features such as a female-biased sex ratio. These findings favor the election of this species as a viable biocontrol agent for augmentative releases because the favorable proportion of adult females emerging from superparasitized pupa should contribute to better pest control.  相似文献   

12.
To fully understand odonate life cycles, it is vital to analyse the patterns of larval growth, which are tightly associated with variations in environmental factors. However, the identification of larval instars is often difficult, especially for early development stages. We hypothesise that pond hydroperiod influences odonate larval growth, and test this idea with novel information about the environmental characteristics of 12 study ponds in Terceira Island (Azores). This study, which represents the first analysis of larval development of Odonata in the Azores, involved determining the instars of development and growth ratios. We measured the morphological characteristics of 898 Odonata larvae, and found that they significantly differed between temporary and permanent ponds. To estimate the larval instars, we used two methods: frequency distribution methods and correlation diagrams between body characteristics. The first method was the most effective, allowing the estimation of 17 instars for Anax imperator, 13 for Sympetrum fonscolombii and 10 for Ischnura hastata, as well as growth ratios between instars for head width, total length, abdomen length, wings and antenna length. Our results also suggest that a combination of the two methods is the most appropriate strategy for estimating the number of instars and growth ratios during larval development.  相似文献   

13.
The slipper shell snail Crepidula fornicata forms dense assemblages along much of the European coast, where it co-occurs with oysters. We examined the susceptibility of slipper shell larvae to predation by suspension-feeders, including adults of their own species. In particular, we compared filtration rates on phytoplankton with those on larvae, and determined the extent to which consumption of larvae varied with adult size, larval size, and with the presence of alternative food (phytoplankton). We also examined the ability of competent larvae to metamorphose successfully in the presence of feeding adults. For each experiment, adults were held in plastic jars with seawater or phytoplankton suspension and allowed to graze on larvae (101 larvae per jar) for 4-6 h at room temperature (21-23 °C); larvae were kept in circulation with gentle aeration. Adults of C. fornicata ingested substantial numbers of larvae over the complete range of sizes tested, about 450-850 μm shell length. Ingestion rates were reduced by 43-50% in the presence of phytoplankton, and were not correlated with adult shell length. The rates at which larvae were removed by adult slipper shells were generally lower than predicted from the rates at which the same adults ingested phytoplankton, suggesting either some ability of larvae to avoid capture or some difficulty of adults in consuming larvae entrained into their feeding currents. Slipper shell larvae were also readily consumed by adult oysters (Ostrea edulis and Crassostrea gigas), and indeed oysters consumed larvae at faster rates than predicted from their phytoplankton ingestion rates. Nevertheless, substantial numbers of competent larvae managed to metamorphose successfully during the test periods, either on the sides of the jars they were in or on the adults' shells, suggesting that recruitment probably continues in the field even when suspension-feeding adults are at high concentrations in the benthos.  相似文献   

14.
The diet, feeding success (prey number and total volume per gut, and maximum prey width) and trophic niche width of the labrisomid blenny Auchenionchus variolosus (Valenciennes, 1836) was studied during its larval development (3.93–17.26 mm standard length). Individuals were collected in October 2012 and October 2013 in nearshore waters (<500 m offshore) from Bahía Valparaíso, central Chile with Bongo nets. When compared to the same length range, larval A. variolosus collected during 2013 showed larger upper jaw‐at‐sizes than those from 2012. This coincided with a reduction in relative importance (%IRI) of the main prey item, copepod nauplii, from ~90 to ~73%. Feeding incidence (FI) was high throughout larval development, varying from 97.3 to 100%, being similar throughout the larval development. Prey items per gut (PIPG) ranged from 0 to 35 prey, showing no differences among years. Total volume per gut (TVPG) was positively correlated with larval length, and at given larval size, TVPG ingested by larval A. variolosus was larger during 2013 (0.0607 mm3) than during 2012 (0.0301 mm3). Prey width range was 47.47–700.94 μm and was positively correlated with standard length (SL). Niche breadth was independent of larval size and did not change during larval development in 2012 or 2013. The study helps to understand the trophic interactions occurring in nearshore waters off rocky reef environments from mid‐latitudes of the Southeast Pacific coasts.  相似文献   

15.
Stag beetle larvae generally feed on decaying wood; however, it was unknown whether they can use wood-rotting fungi alone as food. Here, to clarify this, newly hatched larvae of Dorcus rectus (Motschulsky) (Coleoptera: Lucanidae) were reared for 14 days on artificial diets containing a fixed amount of freeze-dried mycelia of the following fungi: Bjerkandera adusta, Trametes versicolor, Pleurotus ostreatus, and Fomitopsis pinicola. The mean incremental gain in larval body mass was greatest on diets containing B. adusta, followed by T. versicolor, P. ostreatus, and F. pinicola. The growth rate of body mass correlated positively with mycelial nitrogen content of the different fungi. It also correlated positively with the mycelial content of B. adusta in the diet. Addition of antibiotics to diets with mycelia nearly halved larval growth, indicating that larvae were able to use fungal mycelia as food without the assistance of associated microbes although the microbes positively affected larval growth. Four newly hatched larvae reared on artificial diets containing B. adusta mycelia developed to the second instar in 21-34 days; and one developed to the third (=final) instar. This study provides evidence that fungi may constitute the bulk of the diet of D. rectus larvae.  相似文献   

16.
SUMMARY. 1. Food availability during instar F-3 affected duration of instar F-3 of larval Ischnura vertiealis (Say) maintained in the laboratory but did not affect the increase in head width at the moult to instar F-2.
2. Food availability during instar F-2 altered both duration in instar F-2 and weight per unit head width of newly moulted F-l larvae, but not the increase in head width at the moult to instar F-1.
3. Food availability during instar F-3 had no effect on instar duration, weight per unit head width, or increase in head width of F-2 larvae at the moult to instar F-l.
4. Survival of larval Coenagrion resolution (Hagen) reared in the laboratory was dependent on mean number of Daphnia offered per day. In addition, larvae fed less frequently, but on the same mean number of Daphnia per day. had lower survival rates than larvae fed more frequently.  相似文献   

17.
Granivorous ground beetles (Coleoptera: Carabidae) are ubiquitous throughout temperate agricultural systems, and reduce weed seedbanks. However, trade-offs may exist between tillage frequency and ecosystem services of invertebrate seed predators, especially those in the larval stages, which have relatively poor resistance to disturbance. While much research has focused on adult activity patterns and the conservation biocontrol services they provide, almost nothing is known about carabid biology and habitat requirements during larval stages, despite the fact that adult recruitment is determined by factors that promote larval survival. We present data on larval and adult Harpalus pennsylvanicus Dej., a common weed seed predator across North America, from two experiments examining its activity density across tillage and cover-cropping treatments in organic tomato systems. Larvae emerged 4–6 weeks after the adult activity peak, and larval activity density was up to 10 times higher in no-till crop environments than in cultivated areas. After a long disturbance interval, seasonal cultivation had no effect on foraging activity of adults, but reduced larval activity density in both experiments. Additionally, larvae positively correlated with living weed biomass in no-till treatments, suggesting the importance of plant-based resources in oviposition site choice. Compared with adults, larvae are relatively immobile and vulnerable to disturbance; thus, weed management strategies that rely on frequent cultivation may undermine the ecosystem services provided by granivorous insects.  相似文献   

18.
Present study was performed to know the infection status of Gnathostoma sp. larvae in swamp eels from Cambodia. We purchased total 30 Asian swamp eels, Monopterus albus, from local markets in Pursat and Takeo Provinces and Phnom Penh on May and November 2017 and May 2018. All collected eels were transferred to our laboratory with ice and each of them was examined by artificial digestion method. A total of 15 larval gnathostomes (1–5 larvae) were detected from 55.6% (5/9) swamp eels in Pursat Province. No larval gnathostomes were found in 21 swamp eels in Takeo Province and Phnom Penh. The advanced third-stage larvae (AdL3) detected were 2.575–3.825 (3.250) mm in length and 0.375–0.425 (0.386) mm in width. They had the characteristic head bulb (av. 0.104×0.218 mm) with 4 rows of hooklets, long muscular esophagus (1.048 mm), and 2 pairs of cervical sacs (0.615 mm). The number of hooklets in 4 rows on the head bulb was 41, 44, 47, and 50. In scanning electron microscopy, characteristic features were 4 rows of hooklets on the head bulb, cervical papillae, tegumental spines regularly arranged in transverse striations, and anus. The larval gnathostomes were identified as AdL3 of Gnathostoma spinigerum based on the morphological characters. By the present study, it has been confirmed that G. spinigerum larvae are infected in Asian swamp eels, M. albus, in Pursat Province, Cambodia.  相似文献   

19.
明确圆柏大痣小蜂Megastigmus sabinae Xu et He(1989)幼虫的最佳分龄指标、幼虫龄数与各虫龄龄期,为探明圆柏大痣小蜂幼虫期的生长规律奠定基础。本研究通过测量圆柏大痣小蜂幼虫上颚关节宽、头宽、体宽和体长4个形态指标,利用频次分布推测幼虫龄数,运用Crosby生长法则和线性回归的方法判断圆柏大痣小蜂幼虫的最佳分龄指标并验证幼虫的龄数。将最佳分龄指标作为龄期判断依据,根据测量结果对其幼虫龄期进行划分。圆柏大痣小蜂幼虫共划分为5个龄期,上颚关节宽为圆柏大痣小蜂幼虫龄期划分的最佳形态指标,各龄幼虫的历期约为30 d、200 d、30 d、30 d、15 d,共305 d,主要以2龄越冬。  相似文献   

20.
Males of several animals increase their reproductive success by territorial behaviour. In butterflies, males may defend a territory (i.e., territorial perching tactic), but this is assumed to be an energetically costly way to locate mates. Limitations of the energy budget may affect fight performance, and may, consequently, force males to adopt an alternative non-territorial searching behaviour (i.e., patrolling tactic) to maximize reproductive success. In this study, we tested to what extent behavioural tactics adopted by adult males of the butterfly Pararge aegeria (L.) were affected by the nutritional conditions during the larval stage. We compared the occurrence of territorial versus patrolling behaviour, lipid mass, flight muscle ratio, metabolic rate and spermatophore production of low quality males that were reared as a larva on drought-stressed host plants and control, high quality males. Low quality males were less likely to adopt the territorial perching tactic and emerged as adults with lower lipid mass than high quality males, but they were able to restore their lipid mass through adult feeding (and perhaps the breakdown of flight muscles). Host plant quality also affected spermatophore size. Independent of the larval food treatment, territorial perching males metabolised more lipids than non-territorial males, produced larger spermatophores and copulated for longer than males adopting non-territorial behaviour. We discuss the results relative to the co-existence of the behavioural tactics (perching and patrolling).  相似文献   

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