若干种天牛幼虫外部形态结构与危害特性的适应关系

本研究在观察比较隶属于鞘翅目天牛科3亚科16种天牛幼虫的外部形态特征的基础上,从结构与功能的角度,初步总结了天牛幼虫外部形态特征与危害特性的关系。结果表明:天牛亚科幼虫的上颚为圆凿型,沟胫天牛亚科和幽天牛亚科的幼虫上颚则为楔型。上颚圆凿型的天牛幼虫,外露上颚部分占头部面积比例值越小,上颚越发达;上颚楔型的天牛幼虫,外露上颚部分占头部面积比例值越大,上颚越发达。及时将粪屑排出蛀道外的幼虫之前胸背板、背腹部步泡突较发达,具有粗大的瘤突,气门相对面积比例较大;相反,不及时排出粪屑类的幼虫之前胸背板、背腹部泡突不发达,多具细皱纹,气门相对面积比例较小。     

二种萤火虫幼虫捕食行为及头部功能性结构观察比较

对短角窗萤Diaphanes sp.和胸窗萤Pyrocoelia pectoralis Olivier幼虫的捕食行为进行观察。发现短角窗萤捕食蚯蚓而胸窗萤则捕食蜗牛。利用扫描电镜对短角窗萤和胸窗萤幼虫的头部及口器进行观察比较。发现2种幼虫均具有1对侧单眼,1对发达的、左右对称的3节触角。2种幼虫口器非常发达,具1对锋利的、中空的镰刀状上颚,1对下颚须,1对下唇须,1对内颚叶。2种萤火虫口器最具特别的结构在于:短角窗萤上颚的2/3处内侧着生1个球形结构,上面着生1层齿状结构,而胸窗萤则在上颚基部内侧弯曲成齿状突起。     

蚊幼虫体表微细结构的扫描电镜观察及分类学研究

本文用扫描电镜观察、比较了14种库蚊和6种其他蚊属的幼虫颅壳、呼吸管及尾节的体表微细结构,发现在颅壳上的微棘排列成多角形,在呼吸管和尾节上的微棘则排列成直线.这些微棘在不同区域排列有变化,但在固定的区域却很稳定,具有种内稳定性和种间差异,可以作为分类特征.本文共对20种蚊幼虫的体表微棘图式进行了描述,并以组为单位,对同组内各近似种的微棘图式进行比较和小结,提出它们的区别特征,用于鉴别近似种;根据体表图式,对库蚊个别种类的分类位置提出了不同的看法,讨论了体表微棘的起源及其分类的意义.     

星天牛幼虫龄期的划分

本文测量了人工饲养的星天牛Anoplophora chinensis(Forster)幼虫的9个形态结构数据,运用频次分布、均差分析和回归分析对测量数据进行统计分析,结果表明,星天牛幼虫可分5龄,其额宽是最佳的分龄结构,其次是上颚长和上颚宽。     

大叶黄杨斑蛾Pryeria sinica Moore幼虫上颚的一种畸形构造

最近作者在进行斑蛾科幼虫外形比较研究时,曾在185个大叶黄杨斑蛾幼虫中发现有一个幼虫具有畸形构造的上颚。下面把它和正常的上颚加以比较和叙述。 正常上颚的基部具有一个关节突(图1,Cd1)和一个关节臼Col。由这种关节突和头部腹面的关节盂构成杵臼关节。关节臼和头部的突起也构成同样的关系,上颚的尖端具有3个齿状构造。整个上颚的中面低凹,并有隆起脊3条(图1,A)。上颚的侧面拱曲,具有刚毛两根(图1,B)。     

绿豆象幼虫虫龄的划分及末龄幼虫头部形态和感器观察

【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。     

胸窗萤幼虫对灰巴蜗牛的捕食机制初探

本文对胸窗萤Pyrocoelia pectoralis Oliver 4龄幼虫捕食灰巴蜗牛Bradybaena ravida Benson的机制进行了初步探索。通过解剖幼虫消化道进行观察,发现幼虫的食道在与上颚基部骨化结构相连处分为2支,呈Y型结构,分别与2个上颚的中空管道相通;无毒腺结构存在。将幼虫头部及消化道各部分提取液注射到灰巴蜗牛体内后发现中肠提取液对蜗牛的致死效果显著高于头部和消化道其它部分提取液对蜗牛的致死效果(df=68,P<0.05),比较不同浓度中肠提取液对蜗牛致死效果的差异后发现,浓度为5 mg/mL的中肠提取液对蜗牛的致死时间(15.96±4.48)min与幼虫正常捕食的时间(14.47±2.32)min最为相近。     

1954年长沙市蚊虫初步调查报告

一.1954年3—10月,在长沙市初步调查蚊虫,共採得蚊种9属26种。其中有按蚊属1种、拟三翅蚊属1种、Uraunotaenia属2种、Orthopodomyia属1种、番蚊属1-种、曼蚊属1种、阿蚊属土种、蚊属3种及库蚊属15种(其中2种未定名)。所採得的9属26种蚊虫中,有树竹拟三翅蚊、Uranotaenia bimaculata、Orthopodo-myia anopheloides及罗宗番蚊4种,在湖南尚系首次报告。 二.长沙市蚊种的分佈,郊區有25种、中心區有13种。较为常见者有致乏库蚊、三 带喙库蚊、中华按蚊、白纹伊蚊貪食库蚊及骚扰阿蚊六种。 三.”长沙市各种成蚊的停歇处,主要是山陵、住宅、郊野及猪、牛栏。 四.在长沙市所发现的蚊虫中,只发现17种幼虫。各蚊种幼虫孳生地的范围是有差别的。致乏库蚊及贫食库蚊范围最广;Uranotaenia bimaculata、othopodomyiaanopheloides、黑足伊蚊的幼虫,只在树洞渍水中发现。 五.各蚊种幼虫间共生情况,已在文中讨论。 六.在调查的过程中,发现黑足伊蚊在傍晚时吸吮人血。 七.将湖南省已肢知蚊虫编为俭索表,以便有关工作人员之参考。     

四川省雅安地区蚊类越冬情况的调查

1955年至1984年对四川雅安地区25种蚊类越冬情况作了初步调查,结果发现以成蚊越冬者6种;以成、幼虫越冬者1种;以成虫及卵越冬者2种,以幼虫越冬者4种,以幼虫及卵越冬者1种;以卵越冬者2种;无明显越冬期,冬季仍能繁殖发育者9种,各蚊种的越冬情况记述如下。     

致乏库蚊抗药性的研究——Ⅱ.几种不同抗性水平的致乏库蚊幼虫各年龄对DDT敏感度的变化

一、前言 一般认为蚊幼虫的年龄增加,对杀虫剂的敏感度会随之降低。作者曾于探讨幼虫抗药性的适宜年龄工作中,测定过具有不同抗性水平的致乏库蚊2、3和4龄幼虫对杀虫剂敏感度的变化,结果显示出3和4龄幼虫敏感度的降低,除因年龄增长外,还与抗性水平有一定关系。本文选择了几种不同抗性水平的室内、外品系,系统地测定各年龄幼虫对DDT敏感度的变化,希望进一步地证实抗性水平对年龄间敏感度变化的影响。     

The Morphology of the Mandibles in Zoea I Larvae of the Burrowing Shrimp Genera <Emphasis Type="Italic">Upogebia</Emphasis> (Gebiidea) and <Emphasis Type="Italic">Nihonotrypaea</Emphasis> (Axiidea)

The mandibles in the first zoeal stage of five species of the burrowing shrimp genera Upogebia (infraorder Gebiidea) and Nihonotrypaea (infraorder Axiidea) have been examined by scanning electron microscopy. The general shape of the mandibles in Upogebia zoeae is similar to that in Anomura larvae; in Nihonotrypaea, it is intermediate between the mandibles of anomuran and caridean shrimp larvae. The asymmetry of the mandibles, which is more pronounced in Nihonotrypaea, is confirmed. Species-specific features of the structure of the incisor process are found in three Upogebia species, while two Nihonotrypaea species almost do not differ in the mandible structure in their zoea I larvae. The morphological features of the mandibles indicate differences in the diet of Upogebia and Nihonotrypaea larvae. Under natural conditions, zoea I of the studied Nihonotrypaea species may feed on diatoms, which should be taken into account when rearing these decapod larvae in the laboratory.     

Chromosomal Evidence on the Sporogony of Amblyospora californica (Microspora: Amblyosporidae) in Culex tarsalis (Diptera: Culicidae)

ABSTRACT. Amblyospora californica is a polymorphic, eukaryotic microsporidian. Three types of sporogony producing three types of spores occur in male larvae and female adults of its mosquito host, Culex tarsalis , and an alternate copepod host, Acanthocyclops vernalis. Development of A. californica in male larvae includes merogony and sporogony. Karyogamy and meiosis was observed in sporogony in male larvae but not in the female adult or in the copepod. Chromosomal evidence showed that sporogony included two consecutive meiotic divisions and a subsequent mitosis forming an octosporont, ultimately containing eight haploid, uninucleate mature spores. In this species, the haploid number of chromosomes is nine. Macrosporoblasts and macrospores, containing 1, 2 or more nuclei, can be seen in infected male larvae. The stage of sporogony in which cytokinesis was arrested seems to determine the number of nuclei. Those with only one nucleus, we believe are due to failed nuclear division at meiosis. Although A. californica displayed a process of karyogamy and meiosis similar to that of the species from Cx. salinarius , they may not be the same species because of the difference in their chromosome numbers.     

Intraguild predation among ladybeetles and a green lacewing: do the larval spines of Curinus coeruleus(Coleoptera: Coccinellidae) serve a defensive function?

Laboratory experiments examined interspecific interactions between larvae of three coccinellid species, Curinus coeruleus Mulsant (Chilocorinae), Harmonia axyridis Pallas and Olla v-nigrum (Mulsant) (Coccinellinae), and between these and larvae of the green lacewing, Chrysoperla rufilabris (Burmeister). Larvae of C. coeruleus, although defended on their dorsal surface with long spines, had the smallest mandibles, were the slowest-moving, and the least successful in interspecific larval combat. The long spines of third instar C. coeruleusappeared to reduce their palatability as food to H. axyridis and O. v-nigrum larvae in choice tests with dead larvae, but were not an effective defence against these species in Petri dish arenas. Larvae of O. v-nigrum had a smooth dorsal surface, were intermediate in terms of mandible size, but were the fastest moving, a trait that benefited their survival in intraguild combat. Larvae of H. axyridis were intermediate with respect to dorsal spines and speed of movement, but had the largest mandibles. This species was the most effective intraguild combatant among the coccinellids and the only one to successfully compete against C. rufilabris larvae of similar age. The speed, manoeuverability and long mandibles of C. rufilabris enabled them to impale coccinellid larvae at a relatively safe distance. The spines of C. coeruleus larvae impeded laterally oriented attacks by C. rufilabris, but did not provide sustained protection from repeated attacks. Success in these interactions appeared largely a function of offensive weaponry (mandible size and morphology) and speed of movement, although the role of dorsal spines as defensive structures was not ruled out. Rates of larval cannibalism were highest for C. rufilabris and largely mirrored the level of aggression observed in interspecific combat for each species.     

Modulation in the feeding prey capture of the ant-lion, Myrmeleon crudelis

Ant-lions are pit-building larvae (Neuroptera: Myrmeleontidae), which possess relatively large mandibles used for catching and consuming prey. Few studies involving terrestrial arthropod larva have investigated prey capture behavior and kinematics and no study has shown modulation of strike kinematics. We examined feeding kinematics of the ant-lion, Myrmeleon crudelis, using high-speed video to investigate whether larvae modulate strike behavior based on prey location relative to the mandible. Based on seven capture events from five M. crudelis, the strike took 17.60 ± 2.92?msec and was characterized by near-simultaneous contact of both mandibles with the prey. Modulation of the angular velocity of the mandibles based on prey location was clearly demonstrated. M. crudelis larvae attempted to simultaneously contact prey with both mandibles by increasing mean angular velocity of the far mandible (65 ± 21?rad?sec(-1) ) compared with the near mandible (35 ± 14?rad?sec(-1) ). Furthermore, kinematic results showed a significant difference for mean angular velocity between the two mandibles (P<0.005). Given the lengthy strike duration compared with other fast-striking arthropods, these data suggest that there is a tradeoff between the ability to modulate strike behavior for accurate simultaneous mandible contact and the overall velocity of the strike. The ability to modulate prey capture behavior may increase dietary breadth and capture success rate in these predatory larvae by allowing responsive adjustment to small-scale variations in prey size, presentation, and escape response.     

Comparative morphology of terminal-instar larvae of Cynipoidea: phylogenetic implications

We describe the external morphology of the terminal-instar larvae of 30 species of Cynipoidea (Hymenoptera), with special reference to the head capsule and mouthparts. Twenty-five of the species belong to the Cynipidae and are gall inducers or phytophagous inquilines (guests) in galls, while five represent different insect-parasitic lineages of the Cynipoidea. Although we find only limited variation in body shape, the head sclerites and mandibles offer many characters of potential phylogenetic value. For instance, the mandibles of the parasitoids have one large pointed tooth, with several smaller dents along the inner margin in core figitids, whereas the phytophagous gall inducers and inquilines have mandibles with two or three blunt teeth of subequal size. The mandibles of inquiline larvae are unique in being covered by vertical striations and in having a dominating, broad second tooth. We summarize the qualitative variation among the studied terminal-instar larvae in terms of 33 morphological characters and one life-history trait and examine the phylogenetic implications of these data by running parsimony analyses under uniform character weights and under implied weights (Goloboff weights). The analysis under uniform weights is poorly resolved but the relationships suggested by the implied-weights analysis are largely congruent with previous analyses of adult morphology and molecular data. The larval data support inclusion of the genus Liposthenes in the Neaylax – Isocolus clade, in agreement with the molecular data but in weak conflict with adult morphology. However, the larval data agree with adult morphology and conflict with the molecular data in supporting monophyly of the inquilines.     

A new microsporidian parasite of the mosquito Aedes taeniorhynchus

A new species of microsporidium is described from the mosquito Aedes taeniorhynchus. This microsporidium is vertically transmitted and exhibits dimorphic development with one sequence leading to formation of short pyriform, uninucleate spores in male fourth instar larvae, pupae, and adults, and the other sequence leading to formation of diplocaryotic stages and cylindrical spores in adult females. Vertical transmission is apparently limited to a single generation, and the uninucleate spores are not transmissible per os to larvae.     

Tadpoles of three common anuran species from Thailand do not prey on mosquito larvae

Tadpoles are often considered to be predators of mosquito larvae and are therefore beneficial for the control of certain disease vectors. Nevertheless, only a few species have actually been recorded to prey on mosquito larvae. The mosquito larvae predation rates of tadpoles of three common Thai anuran species (Bufo melanostictus, Kaloula pulchra and Hylarana raniceps) were experimentally tested. Tadpoles in varying developmental stages were used to assess a size/age effect on the predation rate. In addition, different instars of Culex quinquefasciatus were used in order to assess a prey size effect on the predation rates. All three species failed to show any evidence of mosquito larvae predation. Neither small nor large tadpoles fed on mosquito larvae. Prey size also did not affect predation. Although tadpoles do not feed on mosquito larvae, there may be other direct or indirect inter‐specific interactions that adversely impact the development of larvae in shared habitats with tadpoles.