肥须亚麻蝇幼虫不同发育阶段气门形态学变化

为了满足实际工作中利用蝇类幼虫日龄推断尸体死后间隔时间的需求,本文采用显微镜观察不同龄期肥须亚麻蝇 Parasarcophaga crassipalpis (Macquart)幼虫气门的形态学变化,通过计算机图像分析系统对幼虫的前、后气门等可用于判断幼虫生长发育的形态学指标进行测量。结果表明：肥须亚麻蝇幼虫前、后气门随时间而发生规律性的变化,幼虫前气门色素管部的平均光密度及其长宽比,以及后气门的平均光密度这 3 项指标是推算幼虫日龄较理想的指标,对法医学中尸体死亡时间的推测具有重要的指示意义。此外,叠龄期作为幼虫发育的必经阶段,可为特殊时间点的推测提供可靠依据。     

The application of scanning electron microscopy to the systematics of the neotropical Peripatidae (Onychophora)

The taxonomy of the New World Peripatidae is poorly known both because of their rarity and difficulty in the determination of specimens. The distribution of papillae on the dorsal integument is an important taxonomic; character but is difficult to interpret under the light microscope. In this study the integument of a range of New World onychophoran species was studied using scanning electron microscopy. Twenty-one species were examined. Three species of Peripatopsidae were also studied for comparison. This technique revealed (a) the pattern of distribution of papillae on the integument, and (b) the morphology of the papillae. A pattern of three smaller papillae between two large was common to many species. Differences observed in some species were probably modifications of this basic pattern. There was interspecific variation in the number of scales in the apical and basal pieces of the papillae. The specimens examined fell into two main groups: (1) species with more than three scale ranks in the apical piece ( Oroperipatus and Peripatus ) and (2) species with three or fewer scale ranks ( Epiperipatus, Macroperipatus and others). The results thus support a distinction between Epiperipatus and Peripatus . However Macroperipatus is shown not to be a natural group. The relationships of some species which did not fit into this pattern are discussed. This paper shows scanning electron microscopy to be a potentially useful technique in a revision of the New World Peripatidae.     

Ootaxonomy and eggshell ultrastructure of Phlebotomus sandflies

The eggshell structure of four sandfly species: Phlebotomus perniciosus Newstead, P.perfiliewi Parrot, P.papatasi Scopoli and P.duboscqi Neveu-Lemaire, was examined by scanning and transmission electron microscopy (SEM and TEM). At the TEM level, the eggshell appears to have a homogeneous vitelline envelope and a thick chorion. At SEM level, the eggshell of all species is characterized by the outer chorion forming a series of fifteen to twenty longitudinal sinuous ridges, cross-linked in places to form a pattern of polygons, each line of the chorion consisting of columns arranged in a palisade. The aeropyle region of the egg is described for the first time in phlebotomine sandflies. Specific characters of the eggshell topography are described for distinguishing between these and other species of Phlebotomus.     

Posterior spiracles of fourth instar larvae of four species of phlebotomine sand flies (Diptera: Psychodidae) under scanning electron microscopy

In the present study, posterior spiracles of laboratory-reared fourth instar larvae of Lutzomyia longipalpis, L. migonei, L. lenti, and L. whitmani (Diptera: Psychodidae) of the State of Ceará, Brazil, were examined under scanning electron microscopy. The number of papillae of spiracles examined varied according to the species examined, but no intraspecific differences were found. The importance of this structure to sand fly larva identification and phylogeny is commented.     

八种散白蚁和一种异白蚁翅面微刻点的扫描电镜观察──(等翅目:鼻白蚁科)

用扫描电镜观察八种散白蚁和一种异白蚁有翅成虫翅面微刻点．结果表明,除了观察到文献中已报道的微刻点类型（舌状乳突、尖头状乳突和粉刺状突起）外,还发现有小刺突和毛．而且同一种白蚁翅背、腹面的微刻点类型存在明显的差异．根据微刻点类型就细颚异白蚁的分类地位作了初步探讨．     

Ultrastructural observations of Beauveria bassiana infection in Xylotrechus rusticus larvae

In the present study we investigated the infection process of Beauveria bassiana on Xylotrechus rusticus larvae using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM results showed that B. bassiana spores germinated on the surface of the larval body and invaded the larva as an appressorium. The hyphae then germinated from the spores and spread throughout the larval body. After the death of the larva, conidiophores formed at one end of the hypha on the surface of the larval body and prepared for a new round of infection. The TEM results showed severe damage to the larval cuticle after hyphae infection. The structure of the cuticle became thinner and eventually flocculent; muscle tissues were dissociated and eventually stuck to the hyphae, and the corpus adiposum was loose and deformed, and eventually degraded.     

Ultrastructure aspects of Brycon gouldingi (Teleostei,Characidae) related to swimming ability and feeding during larval development

The larval ultrastructure of Brycon gouldingi related to swimming and feeding from hatching to total yolk absorption is described from scanning electron micrographs. Newly hatched larvae (time zero) had no mouth opening, undefined optic vesicles, an olfactory plate visible as a shallow depression, rudimentary gill arches, neural groove, embryonic fin and a primary neuromast in the dorsal region of the head. At the time of yolk absorption, 55 h post hatching, the larvae presented an optic vesicle comprising an optic cup and crystalline lens; a mouth with tongue, tapered teeth and taste buds; a ciliated olfactory cavity; branched gill arches; filled neural groove signalling central nervous system development; caudal, pectoral, dorsal and anal fins; and neuromasts distributed throughout the head and body. These characters are related to prey capture and swimming ability, key aspects of survival during the larval stage. The results of this study provide important information for exploitation and aquaculture of B. gouldingi.     

Larval morphology of the lesser housefly, Fannia canicularis

The morphology of all larval instars of Fannia canicularis (Linnaeus) (Diptera: Fanniidae) is documented using a combination of light and scanning electron microscopy. The following structures are documented for all instars: antennal complex; maxillary palpus; facial mask; cephaloskeleton; ventral organ; anterior spiracle; Keilin's organ; posterior spiracle; fleshy processes, and anal pad. Structures reported for the first time for all instars include: two pairs of lateral prominences on the prothoracic segment; additional ventrolateral prominences on the second thoracic segment, and a papilla at the base of the posterior spiracle. Other structures reported for the first time are anterior spiracles in the first instar and a serrated tip on the mouthhook in the second instar. A trichoid sensillum on the posterior spiracular plate, representing a sensory organ otherwise unknown in the Calyptratae, is described in the second and third instars. Results are discussed and compared with existing knowledge on dipteran larval morphology.     

Morphological development of larval cobia Rachycentron canadum and the influence of dietary taurine supplementation

The morphological development of larval cobia Rachycentron canadum from 3 days post hatch (dph) until weaning (27 dph) was examined using S.E.M. Two groups of fish were studied: a control group (CF), reared under standard feeding protocol, and a group in which prey items were enriched with supplemental taurine (4 g l(-1) day(-1) ; TF). TF fish grew faster (P < 0·001), attained greater size (mean ±s.e. 55·1 ± 1·5 v. 33·9 ± 1·0 mm total length) and had better survival (mean ±s.e. 29·3 ± 0·4 v. 7·1 ± 1·2 %) than CF fish. Canonical variance analysis confirmed findings with respect to differences in growth between the treatment groups with separation being explained by two cranial measurements. S.E.M. revealed that 3 dph larvae of R. canadum (in both groups) possess preopercular spines, superficial neuromasts on the head and body, taste buds in the mouth, an olfactory epithelium which takes the form of simple concave depressions, and primordial gill arches. Gill filaments start to form as early as 6 dph and lamellae buds are visible at 8 dph in both groups. In CF fish, the cephalic lateral line system continues its development at 12-14 dph with invagination of both supra- and infraorbital canals. At the same time, a thorn-like or acanthoid crest forms above the eye. At 14 dph, invaginations of the mandibular and preopercular canals are visible and around 22 dph enclosure of all cranial canals nears completion. In CF larvae, however, completely enclosed cranial canals were not observed within the course of the trial, i.e. 27 dph. In TF larvae, grooves of the cephalic lateral line system form 4 days earlier than observed in CF larvae of R. canadum (i.e. at 8 dph), with enclosure commencing at 16 dph, and completed by 27 dph. Along the flanks of 6 dph larvae of either treatment, four to five equally spaced neuromasts delineate the future position of the trunk lateral line. As myomeres are added to the growing larvae, new neuromasts appear such that at 16 dph a neuromast is associated with each myomere. By 27 dph, the trunk lateral line starts to invaginate in CF larvae, while it initiates closure in TF larvae. These findings elucidate important features of the larval development of R. canadum and show that dietary taurine supplementation benefits larval development, growth and survival in this species. Moreover, they suggest a conditional requirement for taurine in larval R. canadum.     

Morphology of the tongue dorsal surface in white sea bream (Diplodus sargus sargus)

In the present study, the tongue dorsal surface of the white sea bream Diplodus sargus sargus (Linnaeus, 1758) (teleosts, Sparidae) was studied, to give a support to the knowledge of the anatomical characteristics of the oral cavity of a species with a future potential use in aquaculture. The feeding habits in captivity are one of the critical steps in the species of commercial interest, strictly related to the morphological characteristics of the oropharyngeal cavity. This study was undertaken, using light and scanning electron microscopy, to analyse the morphology of the dorsal tongue surface to show whether relationships are present between the anatomy and the nutritional habits and choices of this farmed species. Three zones, an apex, a body and a root, can be clearly distinguished, with a pouch partially covering the apex. In the pouch, cylindroid and mucosal ridges were observed. Along the whole tongue surface, from the apex to the root, on the medial and lateral parts, many papillae are present, with a fungiform, cylindroid and cone‐like aspect. Taste buds are showed on the dorsal surface of some papillae.     

Caudal polymorphism and cephalic morphology among first-stage larvae of Parelaphostrongylus odocoilei (Protostrongylidae: Elaphostrongylinae) in Dall's sheep from the Mackenzie Mountains, Canada

We demonstrate polymorphism in the structure of the tail among first-stage larvae of Parelaphostrongylus odocoilei (Protostrongylidae). Two distinct larvae, both with a characteristic dorsal spine, include (1) a morphotype with a kinked conical tail marked by 3 distinct transverse folds or joints and a symmetrical terminal tail spike and (2) a morphotype with a digitate terminal region lacking folds or joints and with an asymmetrical, subterminal tail spike. These divergent larval forms had been postulated as perhaps representing distinct species of elaphostrongyline nematodes. Application of a multilocus approach using ITS-2 sequences from the nuclear genome and COX-II sequences from the mitochondrial genome confirmed the identity of these larvae as P. odocoilei. Additionally, based on scanning electron microscopy (low-temperature field emission), the cephalic region of these larvae consisted of a cuticular triradiate stoma surrounded by 6 single circumoral papillae of the inner circle, 10 papillae of the outer circle (4 paired and 2 single), and 2 lateral amphids. Our's is the first demonstration of structural polymorphism among larval conspecifics in the Metastrongyloidea and Strongylida. The basis for this polymorphism remains undetermined, but such phenomena, if discovered to be more widespread, may contribute to continued confusion in discriminating among first-stage larvae for species, genera, and subfamilies within Protostrongylidae.     

Morphology and development of <Emphasis Type="Italic">Pteromalus cerealellae</Emphasis> (Ashmead) (Hymenoptera: Pteromalidae) on <Emphasis Type="Italic">Callosobruchus maculatus</Emphasis> (F.) (Coleoptera: Chrysomelidae)

Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae) is an ectoparasitoid of several stored-product insect pests. Very little information has been published on its biology and development in host larvae, which typically are concealed within seeds. We documented the development of P. cerealellae within fourth instar larvae of its concealed host, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) infesting cowpea seeds. The preimaginal life stages of the parasitoid were characterized for the first time using morphological structures revealed by microscopic techniques including scanning electron microscopy. Pteromalus cerealellae produces hymenopteriform eggs and larvae. Eggs hatch into 13-segmented first instar larvae with peripneustic condition of spiracles. The larvae have simple, tusk-like mandibles, whereas the mandibles of the pupae and the adults are of the conventional toothed types. Using statistical analyses of the sizes of the larval mandibles and head capsules in conjunction with reliable characters such as the number of exuviae on the body of parasitoid larvae, cuticular folding, and excretion of the meconium, we recorded four larval instars for P. cerealellae. The data showed significant positive correlations between larval mandible lengths and widths of larval head capsules, as well as between mandible lengths and larval instars, suggesting that mandible length is a good predictor of the number of instars in P. cerealellae. Developmental time from egg to adult emergence was ∼12 d for females and ∼11 days for males at 30 ± 1°C, 70 ± 5% r.h. and 12L:12D photoperiod.     

Functional morphology of the copulatory system of box crabs with long second gonopods (Calappidae,Eubrachyura, Decapoda,Crustacea)

Male True Crabs use two pairs of gonopods to deliver mating products during copulation. Commonly, the second pair is shorter than the first pair, and most research to date has focused on species with short second gonopods. We investigated male and female copulatory organs in Calappula saussurei and Calappa pelii, two species of box crabs (Calappidae) with second gonopods which are longer than the first pair. Scanning electron microscopy and histological cross sectioning show that the female copulatory system is unique in several aspects: the genital duct is part concave and part simple type. The seminal receptacle is divided into two chambers, a ventral chamber of ectodermal and mesodermal origin, and a dorsal chamber of ectodermal origin. This dorsal chamber is the location of spermatophore reception during copulation. A sperm plug closes the dorsal chamber off. We propose that long second gonopods deliver male mating products directly into the dorsal chamber. To date, spermatophore reception has been associated with the mesodermal tissue of the seminal receptacle. The copulatory system of box crabs with long second gonopods shows novel deviations from this general pattern. J. Morphol. 276:77–89, 2015. © 2014 Wiley Periodicals, Inc.     

Larval Gnathostoma hispidum detected in the red banded odd-tooth snake, Dinodon rufozonatum rufozonatum, from China

A total of 205 larval gnathostomes were collected from 18 (22.5%) of 80 red banded odd-tooth snakes, Dinodon rufozonatum rufozonatum, which had been smuggled from China and confiscated at Customs in Busan, Republic of Korea. In order to identify the species, some of the larvae were observed by a light microscope and a scanning electron microscope (SEM). The larvae were 2.18 x 0.29 mm in average size, and had a pair of lips at the anterior end, a muscular esophagus, 2 pairs of cervical sacs, and brownish intestines. The head bulb was characteristically equipped with 4 rows of hooklets; the average number of hooklets in each respective row was 38.6, 40.5, 41.5, and 43.7. In SEM views, the mouth evidenced a pair of lateral lips of equal size in a half-moon shape. Each lip featured a couple of labial papillae and a small amphid located between the 2 papillae. The hooklets on the head bulb had single-pointed, posteriorly-curved tips. The cuticular spines were larger and more densely distributed on the anterior part of the body, and decreased gradually in size and number toward the posterior body. On the basis of these morphological characteristics, the larvae were identified as the third stage larvae of Gnathostoma hispidum.     

Morphology of floral papillae in Maxillaria Ruiz & Pav. (Orchidaceae)

BACKGROUND AND AIMS: The labellar papillae and trichomes of Maxillaria Ruiz & Pav. show great diversity. Although papillae also occur upon other parts of the flower (e.g. column and anther cap), these have not yet been studied. Labellar trichomes of Maxillaria are useful in taxonomy, but hitherto the taxonomic value of floral papillae has not been assessed. The aim of this paper is to describe the range of floral papillae found in Maxillaria and to determine whether papillae are useful as taxonomic characters. METHODS: Light microscopy, histochemistry, low-vacuum scanning and transmission electron microscopy. KEY RESULTS: A total of 75 taxa were studied. Conical papillae with rounded or pointed tips were the most common. The column and anther cap usually bear conical, obpyriform or villiform papillae, whereas those around the stigmatic surface and at the base of the anther are often larger and swollen. Labellar papillae show greater diversity, and may be conical, obpyriform, villiform, fusiform or clavate. Papillae may also occur on multiseriate trichomes that perhaps function as pseudostamens. Labellar papillae contain protein but most lack lipid. The occurrence of starch, however, is more variable. Many papillae contain pigment or act as osmophores, thereby attracting insects. Rewards such as nectar or a protein-rich, wax-like, lipoidal substance may be secreted by papillae onto the labellar surface. Some papillae may have a protective role in preventing desiccation. Species of diverse vegetative morphology may have identical floral papillae, whereas others of similar vegetative morphology may not. CONCLUSIONS: Generally, floral papillae in Maxillaria have little taxonomic value. Nevertheless, the absence of papillae from members of the M. cucullata alliance, the occurrence of clavate papillae with distended apices in the M. rufescens alliance and the presence of papillose trichomes in some species may yet prove to be useful.