Surface structures of the antenna of Mantophasmatodea (Insecta)

The cuticular fine structure of the antenna in Mantophasmatodea (Austrophasmatidae: Hemilobophasma montaguense, Austrophasma gansbaaiense) is described based on SEM images. The armature of sensilla (=s.) on the basiflagellum (14 basal flagellomeres, the distal ones of which are subdivided) and distiflagellum (7 distal flagellomeres) differs strongly. A basiflagellomere has a sporadic vestiture of prominent s. chaetica B as well as distal s. scolopidia and scattered s. coeloconica. The distiflagellum also bears scattered s. chaetica B and s. coeloconica but is also densely covered with sensilla of various other types: numerous s. trichodea and s. basiconica, sporadic s. coelocapitula, and a probably new type of branched sensilla; the distiflagellum is probably the main sensory region, including gustatory and olfactory chemoreception, mechanoreception, and hygroreception. The scape and pedicel also bear s. chaetica B, and s. chaetica A arranged in 4 (scape) or 2 (pedicel) hair-plates. Terminal s. campaniformia are only found on the pedicel. A ‘dark spot’ is present apically on distiflagellomeres 6 (as reported previously) and 1. The two spots are of similar structure and are possibly associated with glands; each comprises a complicated external aperture and a larger internal pouch enclosing a cavity; projections protrude from the pouch walls into the cavity. The surface structure of the basiflagellomeres shows differences that are possibly species specific. An overview is given on antennal apomorphies in Mantophasmatodea.     

SPORANGIAL FRAGMENTS REFERRED TO DICTYOPHYLLUM IN TRIASSIC CHERT FROJVI SARAWAR

Sporangial fragments of several Mesozoic fern taxa are organically preserved in a Triassic (Norian) chert from Sarawak. The more nearly entire annuli in the deposit are divided into two size classes. Structural features of the smaller annuli (capsule diam 0.26-0.3R mm) suggest affinities with the Gleicheniaceae, Matoniaceae, and Dipteridaceae. The three-dimensional preservation of the larger annuli (capsule diam 0.50-0.63 mm) reveals features of annular structure and stomial detail which are usually obscured in compressed specimens. Sporangia featuring these larger annuli were probably more-or-less pyriform and sessile, and they exhibited an oblique, uninterrupted annulus with greatly reduced induration in the stomial and hypostomial regions. The large size of these sporangia and their probable large spore number indicate that they are not conspecific with the Triassic Clathropteris meniscoides Brongn., also reported from Sarawak. On the basis of general morphology and their unusually large size, these sporangia are tentatively referred to Dictyophyllum exile (Brauns) Nathorst.     

Structure and development of antennae in a moth,Manduca sexta

The antenna of the moth, Manduca sexta, comprises two small basal segments and a long (2 cm) flagellum, which is divided into nearly 80 annuli. The annuli bear cuticular scales and small sensory organs, sensilla. A trachea, a blood vessel, and two nerve trunks run through the lumen of the antenna and into the head. Sensilla are arranged in an orderly pattern that is repeated on each flagellar annulus. Each flagellum bears about 10⁵ sensilla, which contain about 2.5 × 10⁵ primary sensory neurons. Clumps of undifferentiated cells (imaginal disks), present in the larva, form pupal antennae during the larval-pupal molt. During the subsequent metamorphic development of the adult, cell divisions, changes in cell shape, and cellular differentiation transform pupal into adult antennae. Sensilla and scales arise and differentiate in the antenna during metamorphosis; regions in which sensilla and scales will arise can be recognized before overt differentiation occurs. All of the flagellar annuli develop synchronously. The dense innervation and neuronal simplicity of antennal flagella, as well as their synchronous development at a late and accessible stage in the animal's life cycle, suit them for studies of neuronal differentiation.     

Separation of cat flea (Siphonaptera: Pulicidae) instars by individual rearing and head width measurements

Two methods to verify whether head width measurements fit Dyar's rule were evaluated for the separation of instars of the cat flea, Ctenocephalides felis (Bouché). Individual rearing was a reliable method of determining larval instar but was labor-intensive. The mean observed head widths were significantly different for each instar (first instar, 0.164 mm; second instar, 0.201 mm; third instar, 0.260 mm) and showed no sexual dimorphism. Head capsule width increased roughly 25% from instar to instar with geometrically progressing growth in accordance with Dyar's rule. However, head capsule width cannot be used to determine the instar of randomly selected larvae because the measurements overlap broadly between instars.     

Acetylcholinesterase activity in antennal receptor neurons of the sphinx moth Manduca sexta

Summary We have used a cytochemical technique to investigate the distribution of acetylcholinesterase (AChE) activity in the antenna of the sphinx moth Manduca sexta. High levels of echothiophate-insensitive (presumably intracellular) AChE activity were found in six different types of antennal receptors localized in specific regions of the three antennal segments of the adult moth. Mechanosensory organs in the scape and pedicel, the Böhm bristles and Johnston's organ, are innervated by AChE-positive neurons. In each annulus of the antennal flagellum, AChE-positive neurons are associated with six sensilla chaetica and a peg organ, probably a sensillum styloconicum. At least 112 receptor neurons (8–10 per annulus) innervating the intersegmental membranes between the 14 distalmost annuli also exhibit high levels of echothiophate-resistant AChE. In addition, each annulus has more than 30 AChE-positive somata in the epidermis of the scale-covered (back) side of the flagellum, and 4 AChE-positive somata reside within the first annulus of the flagellum. Since none of the olfactory receptor neurons show a high level of echothiophateresistant AChE activity, and all known mechanoreceptors are AChE-positive, apparently intracellular AChE activity in the antenna correlates well with mechanosensory functions and is consistent with the idea that these cells employ acetylcholine as a neurotransmitter.     

Head structures of Karoophasma sp. (Hexapoda, Mantophasmatodea) with phylogenetic implications

External and internal head structures of adults of Karoophasma sp. were examined and described. The results are compared with conditions found in other representatives of Mantophasmatodea and members of other lower neopteran groups. The X-shaped apodeme of the frons, the unpigmented oval area enclosed by apical branches of the anterior tentorial arms, the oval sclerotisation at the base of the labrum, the sclerotized rounded apical part of the galea, and the loss of M. labroepipharyngalis are probably autapomorphic for Mantophasmatodea. Plesiomorphic features (groundplan of Neoptera) are the orthognathous condition, the absence of parietal ridges, the absence of a gula, the absence of a 'perforation of the corpotentorium', the multisegmented antennae inserted between the compound eyes, the general arrangement of the mouthparts, the shape and composition of the maxillae and labium, and the nearly complete set of muscles. The presence of a transverse muscle connecting the antennal ampullae is a potential synapomorphy of Orthoptera, Phasmatodea and Dictyoptera. Character states suggesting affinities with Grylloblattodea are the absence of ocelli, the elongation of the corpotentorium, and the very similar mandibles with widely separated bases and completely reduced molae. Whether predacious habits are a synapomorphic feature of Mantophasmatodea and Grylloblattodea is uncertain. The retained orthognathous condition in Mantophasmatodea and Mantodea is likely related with different specialized preying techniques in both groups, i.e. rapid forward pushes of the head–prothorax complex, and the use of raptorial legs, respectively.     

Effect of host age on life cycle and morphological characteristics of Glyptapanteles liparidis (Hymenoptera: Braconidae), a parasitoid of Acronicta rumicis (Lepidoptera: Noctuidae)

The life cycle of Glyptapanteles liparidis was 23.75 ± 1.26, 21.95 ± 2.44 and 20.83 ± 0.78 days when fed on the first, second and third instar larvae of Acronicta rumicis, respectively. Although insufficient numbers hindered statistical analysis, the life cycle of G. liparidis appeared to be shortest, 19 days, when fed on fourth instar larvae. The life cycle of G. liparidis tends to shorten as the larvae of A. rumicis fed upon are more advanced. The body length, forewing length and head capsule width of female G. liparidis fed on first instar larvae of A. rumicis were greater than those of males, while the antennae of males were longer than those of females. When fed on second instar larvae, there was no difference in body length and head capsule width between males and females, but the male antennae were longer than the female, and the female forewings were longer than the male. When fed on third instar larvae, there was no significant difference in head capsule width between the sexes, but female body length and forewing length were greater than the male, and the male antennae were longer than the female. On the whole, females were bigger than males in terms of body length and forewing length, while antennae of the males were longer than those of the females. There was no difference in head capsule width between males and females. Body length, antenna length, forewing length and head capsule width of male and female G. liparidis were relatively larger when fed on first instar larvae of A. rumicis than when fed on second and third instar larvae.     

人工饲养背摇蚊幼虫龄数和龄期的测定

本文采用了人工饲养定期取样的方法,测定了背摇蚊Chironomus dorsalis(Anderson)幼虫的龄数以及各龄的龄期。分别测量不同发育阶段幼虫的头壳长、颏中齿顶端至冠突前缘间距离、头壳宽、颏宽、颏中齿宽、触角长、触角基节长、触角比(触角基节与其余各节的长度之比)等8项指标,以期得到区分和判定幼虫虫龄的最佳形态特征及指标。运用频次分布、均差分析和回归分析对8项指标测量数据进行统计分析,结果表明,背摇蚊幼虫可分4龄,触角长可作为理想的分龄特征和分龄指标,其次是颏中齿顶端至冠突前缘间距离和颏宽。利用种群众数龄期法计算1-4龄幼虫的平均龄期分别为1.32 d、2.00 d、7.51 d和8.39 d,幼虫期共为19.22 d。     

On the head morphology of Grylloblattodea (Insecta) and the systematic position of the order,with a new nomenclature for the head muscles of Dicondylia

External and internal head structures of adults of Galloisiana yuasai (Grylloblattodea) are described. The results are compared with conditions found in representatives of other lower neopteran lineages, notably in Austrophasma and Karoophasma (both Mantophasmatodea). Sutures and ridges of the head capsule are discussed. A new nomenclature for head muscles is presented for the entire Dicondylia (= Zygentoma + Pterygota). Galloisiana (like its sister taxon Grylloblatta) is mostly characterized by plesiomorphic features, such as the largely unspecialized orthopteroid mouthparts, the multisegmented filiform antennae, the presence of trabeculae tentorii, the absence of muscles associated with the antennal ampullae, the presence of musculus stipitalis transversalis (0mx11) and the presence of musculus tentoriofrontalis anterior (0te2). Autapomorphies of Grylloblattodea are: (i) compound eyes composed of only 60 ommatidia or less; (ii) a lacinia with a proximal tooth; (iii) a rounded submentum; (iv) loss of musculus craniohypopharyngealis (0hy3); and (v) loss of musculus labroepipharyngealis (0lb5). The phylogenetic evaluation of 104 characters of the head yields a branching pattern with Grylloblattodea as a sister group of Mantophasmatodea in clade Xenonomia. Putative synapomorphies of both taxa are: (i) a distinct angle (more than 60°) between the submentum and the mentum; (ii) posteriorly oriented labial palpi; (iii) a flat and lobe‐like hypopharynx with a suspensorium far ventrad of the anatomical mouth opening; (iv) loss of musculus tentorioparaglossalis (0la6); and (v) a connection between the antennal ampulla and the supraoesophageal ganglion containing nuclei. Xenonomia is placed in a clade with the two dictyopteran terminals. Another monophyletic group is Embioptera + Phasmatodea. Most branches of the single tree obtained in our analysis are weakly supported. The results clearly show that more data and a much broader taxon sampling are required to clarify the phylogenetic interrelationships of the lower neopteran orders. However, our results narrow down the spectrum of possible solutions, and represent a starting point for future phylogenetic analyses, with an extensive concatenated dataset.     

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。     

An adaptive bivariate kernel smoothing method for determining instars of Austrosimulium tillyardianum (Diptera: Simuliidae) larvae

1. In insects, instar determination is generally based on the frequency distribution of sclerotised body part measurements. Commonly used univariate methods, such as histograms and univariate kernel smoothing, are not sufficient to reflect the distribution of the measurements, because development of sclerotised body parts is multidimensional. 2. This study used an adaptive bivariate kernel smoothing method, based on 10 pairs of separating variables, to differentiate instars of Austrosimulium tillyardianum (Diptera: Simuliidae) larvae in two‐dimensional space. A variable bandwidth matrix was used and separation lines between instars were defined. Using the Crosby growth ratio, Brooks' rule and the new standard recently proposed, larvae were separated into nine instars. It was found that, using the bivariate kernel smoothing method, the clustering accuracy and determination of separation lines as instar class limits were higher than those associated with the univariate kernel smoothing method. With the exceptions of the paired separating variables, head capsule length and antennal segment 3 length (AS3L), the mean probabilities of correct classifications was > 85%. The pair of separating variables that yielded the greatest classification accuracy comprised mandible length (ML) and AS3L, which had mean probabilities of 0.8984. The clustering accuracy was higher for early‐ and late‐instar larvae, but lower for instars 6 and 7. The adaptive bivariate kernel smoothing method was better than univariate methods for instar determination, especially in the detection of divisions between instars and identification of a larval instar.     

Morphogenesis and cellular proliferation pattern in the developing antennal lobe of Drosophila melanogaster

The adult antennal lobe of Drosophila melanogaster emerges from a precursor, the larval antennal lobe. Pulse and pulse-chase labelling of dividing cells in larvae and pupae with bromodeoxyuridine confirmed previous data that some of the interneurons of the adult antennal lobe derive from a lateral neuroblast which starts to divide early in the first larval instar. However, the majority of these interneurons originate from neuroblasts that initiate mitosis at later stages, with a peak of about 10–12 pairs of dividing neuroblasts in the late third larval instar. No clustering of adult antennal lobe neurons according to their birthdates was observed. In contrast to neurons, terminal divisions of glia in the antennal lobe reach their maximum only 12 h after puparium formation.     

Numerical allometric growth of the ommatidia,antennal sensilla,and teeth of foretibial combs in the milkweed bug Oncopeltus fasciatus Dallas (Heteroptera : Lygaeidae)

Oncopeltus fasciatus (Heteroptera : Lygaeidae), the milkweed bug, was bred in captivity. Sampling showed that individuals grow exponentially through their 6 developmental stages with an average linear increase per molt of 42% for the females and 41% for the males. The number of ommatidia per eye grows with negative allometry from an average of 30 in the first instar to 860 in the male and 820 in the female adult. The total number of sensilla on the 2 flagellar segments of an antenna increases with negative allometry during the 5 nymphal stages from a mean of 239 in the first instar to 2462 in the last. At this point, this allometric growth pattern is sharply broken by distinct numerical increase to 7163 on the adult flagellum. The number of teeth composing the foretibial comb, the tool for grooming the distal flagellar segment, grows with negative allometry through all 6 developmental stages. Calculations using previously published data from the migratory locust, Locusta migratoria, revealed the same growth pattern of antennal sensilla: uniform allometric growth during the nymphal development, broken by a conspicuous upward jump to the adult number of sensilla. In the American cockroach, Periplaneta americana, this growth pattern of antennal sensilla holds only for the male; the female continues the nymphal allometric growth into the adult stage. These observations on allometric growth fit three theoretical explanations: 1. Smooth allometric growth is evidence for an aut-adaptation to increasing size. 2. Ex-adaptations to novel ecological niches cause breaks in allometric growth patterns. 3. Chapman's rule, which states that increased mobility correlates with greater olfactory sensitivity, correctly predicts the observed breaks in the allometric growth patterns in the abundance of antennal sensilla.     

A proposal to regard the former family Naididae as a subfamily within Tubificidae (Annelida, Clitellata)

A new species of Placobdelloides is described from crocodiles and river turtles in the Singapore Zoological Gardens. Placobdelloides stellapapillosa is three annulate, has one pair of eyes on somite I or II, six pairs of testisacs, two annuli between the gonopores, one post anal annulus, seven pairs of lobed crop caeca and 12–14 unique star-shaped papillae on the dorsal surface of each annulus. Star-shaped papillae on annulus a2 are typically larger and more pronounced than on annuli a1 and a3. Additional minute cone-shaped papillae may occur between the larger star-shaped papillae or may replace these papillae on annuli a1 and a3. Eggs and young (100–200) are attached by their posterior suckers directly to the ventral surface of the parent.     

麦长管蚜虫龄鉴别特征

【目的】为明确麦长管蚜Sitobion avenae (Fabricius)虫龄鉴别特征, 达到快速鉴别的目的。【方法】在成像观察的基础上, 测定无翅型和有翅型个体不同虫龄的体长、 体宽、 头壳宽、 触角长、 腹管长和后足胫节长6项指标。【结果】麦长管蚜不同翅型个体的体长、 体宽、 头壳宽、 触角长、 腹管长和后足胫节长在虫龄间均存在显著差异, 其中体长、 体宽、 头壳宽和触角长在相邻虫龄之间重叠程度大, 后足胫节长的重叠百分比极小或无重叠; 除有翅型个体4龄若蚜和成蚜之间存在13.93%的重叠外, 腹管长在不同翅型的其他相邻虫龄之间重叠百分比均极小或无重叠, 说明后足胫节长和腹管长可作为虫龄鉴定的主要特征。翅、 触角和尾片的其他外部形态特征在虫龄间也存在一定差异： 3-4龄有翅型若蚜和成蚜虫个体前胸的膨大程度及其翅的长度明显大于同一龄期的无翅型个体, 可用于蚜虫翅型的分辨以及3-4龄有翅若蚜和成蚜的鉴别; 麦长管蚜1和2龄若蚜触角均为5节, 3-4龄若蚜和成蚜的触角均为6节; 同时, 除了成蚜具有完整的尾片外, 1-4龄若蚜尾片均不发达, 说明触角的节数和尾片的发达程度可作为麦长管蚜不同龄期形态鉴别的辅助特征。【结论】以腹管和后足胫节作为麦长管蚜虫龄鉴别的主要特征, 配合其他辅助特征, 如翅的大小、 触角的节数以及尾片的发达程度等, 可达到快速鉴别不同翅型不同龄期蚜虫的目的。     

Effects of temperature on the development of overwintering immature stages of the near‐threatened butterfly Leptalina unicolor (Bremer & Grey) (Lepidoptera: Hesperiidae)

Overwintering larvae of multivoltine and univoltine populations of Leptalina unicolor were reared under various constant and fluctuating temperatures superimposed on a photoperiod of either 12 h of light and 12 h of darkness (LD 12:12) or LD 15:9. Diapause of the larvae terminated in midwinter (by early February). All the larvae of both populations pupated after two molts without feeding and the head capsule width of the final instar larvae was smaller than that of the penultimate instar ones. The photoperiod did not significantly affect larval development, but long‐day conditions (LD 15:9) hastened pupal development. The thermoperiod had a significant effect on the development of the multivoltine population. When multivoltine population larvae were kept under a low fluctuating temperature regime (cryophase/thermophase = 14/20°C), the period until adult eclosion was shorter than that under a constant temperature of 17°C. On the contrary, when larvae were kept under a high fluctuating temperature regime (24/30°C), the period until adult eclosion was longer than that under a constant temperature of 27°C. However, the univoltine population did not show such a reaction to the fluctuating temperature. The durations of final instar larva and pupa of the multivoltine population were shorter than those of the univoltine population. The developmental zeros of penultimate and final instar larvae and pupae of the univoltine population were lower than those of the multivoltine population. The head capsule width of penultimate instar larvae and the forewing length of adults of the univoltine population were larger than those of the multivoltine population for both sexes.     

Life history and bionomics of Arctopsyche grandis (Trichoptera) in a Central Idaho stream

Arctopsyche grandis was studied for two years In a cold stream in central Idaho. Larvae have a one year life cycle consisting of five instars. Three to four instars are present in most months. Growth is rapid in summer with instar I and II passing to IV and V in 30 d or less. Little or no growth occurs during winter. Maximum larval densities were 547 (1977) and 2060 m⁻² (1978) of planar rock surface area. Populations fitted a negative exponential survivorship curve with similar exponents (−0.0078, −0.0103) in both years. Larval growth was generally isometric with head capsule width (403–2197 μm) and weight (0.05–16.23 mg AFDW) increasing by a factor of 1.5 between instars. Net dimensions correlated with head capsule width and nets were made by all instars and maintained throughout the year. Larvae fed preferentially on animals and diatoms avoiding vascular plant detritus. No differences were detected in diet among the instars.     

Morphogenetic and physiological effects of a juvenile hormone analogue on the light brown apple moth,Epiphyas postvittana (Lepidoptera: Tortricidae)

Abstract

The juvenile hormone analogue ZR-619—ethyl 11-methoxy-3,7,11-trimethyl-(2E,4E-dodecadienethiolate) —produced morphological and physiological effects when fed via artificial diet to larvae of Epiphyas postvittana (Walker). Morphological effects included changes in larval head and antennal structures after instar V (supernumerary instars); deformation of pupal and adult structures, particularly in genitalia and wings; and development of individuals with varying mixtures of larval and pupal structures. Physiological effects included prolongation of larval life, increase in larval weight, increase in larval instars, and decrease in fecundity. Effects were directly related to dosage concentrations.     

Descriptions of Four New Species of Criconematoidea (Tylenchina: Nemata) from Southern Chile

Four new species of Criconematoidea are described from Hoste Island, Chile. Criconema certesi n. sp. is distinguished by the fine, spine-like, cuticular extensions on body annuli; projection of annuli into rows of scales on posterior part of body; single, smooth, labial annulus set off by short collar from second (first body) annulus which is about same diameter as first (labial) annulus. Male with prominent caudal alae, slender curved spicules, and four incisures in lateral field. Ogma terrestris n. sp. is distinguished by small scales with rounded tips bearing minute, short bristles; scales number 21 at mid-body; and first (labial) annulus rounded, not retrorse, not set off from succeeding annuli, narrower in diameter from second (first body) annulus. Hemicycliophora macrodorata n. sp. is distinguished by its large size (L = 1.52 [1.28-1.72] mm); large stylet (146 [127-161] μm); annuli = 297 (280-315); tail slightly spicate, lateral field with or without interruptions of incisures, occasional anastomoses; and males with U-shaped spicules. Paratylenchus fueguensis n. sp. is distinguished by its prominent stylet with large, rounded knobs (4-5 μm across); cephalic region rounded not at all set off; lateral field with four incisures; lateral vulvar membranes present; and male tail short, strongly curved (almost 180°) ventrad.