Effect of cibarial armature of mosquitoes (Diptera,Culicidae) on blood-meal haemolysis

Cibarial armatures of mosquitoes act mechanically on the ingested erythrocytes producing the haemolysis of part of the blood meal. The extent of haemolysis, in blood meals examined immediately after ingestion, is less than 5% in mosquitoes without cibarial armature or with “primitive” types of cibarial armature, while up to 50% haemolysis is observed in mosquitoes with more highly evolved types of cibarial armature. Such high levels of haemolysis are produced by the passage of the blood through the mosquito head but not by the incubation of the blood with salivary gland and midgut homogenates from the same mosquito or by injection of the blood into the intestine via the anus.     

Structure and function of the cibarial armature in Simuliidae

Abstract. Cibarial armature morphology in adult female blackflies (Diptera: Simuliidae) is described using scanning electron microscopy. Three distinct types of armature are recognized, comprising those with teeth, e.g. Simulium ochraceum, S. ornatum, S. veracruzanum and S. vorax ; those with spicules, e.g. Austrosimulium bancrofti, S.damnosum, S.exiguum, S.metallicum and S.neavei; and those lacking these projections, e.g. Prosimulium rufipes and S.lineatum.
Whereas the armature is poorly developed in vectors of human onchocerciasis such as S. damnosum, S. exiguum, S. metallicum and S. neavei , the well-developed armature in S. ochraceum, S. veracruzanum and S. vorax does not prevent these species becoming infected with Onchocerca spp. (Nematoda: Onchocercidae). Hence the armature is not primarily a mechanism to counteract microfilaria superinfection.
Since cibarial armatures are more developed in the haematophagous females than in the males of certain Families of flies, e.g. Ceratopogonidae, Culicidae, Phlebotominae and Simuliidae in the sub-order Nematocera, evidently the armature has evolved in response to the blood-feeding habit. As the suction of imbibed blood by the cibarial pump may require a valve mechanism to prevent back-flow, it is suggested that the armature is primarily for this purpose. Secondarily, the cibarial armature presents a damaging barrier against ingested microfilariae.     

Phylogeny of the Pyretophorus Series of Anopheles subgenus Cellia (Diptera: Culicidae)

A cladistic analysis based on morphological characters is presented for the Pyretophorus Series of subgenus Cellia of Anopheles. The cibarial armature was investigated for the first time since the pioneering work of Christophers (1933) , which is still used to define taxonomic series within Cellia, and for the first time ever using scanning electron microscopy. Christophers’ observations of characters of the cibarial armature were corroborated and several novel characters discovered. Despite difficulties in delimiting and encoding morphological characters at the species level, the analysis provided insights into relationships within the Pyretophorus Series. The data support the monophyly of the Series and establish the Oriental species as a monophyletic group. The Afrotropical species are basal and paraphyletic relative to the Oriental species, with Anopheles christyi placed in the most basal position. The pattern of relationships suggests that the capacity to transmit malaria is an ancestral condition subsequently lost independently in several lineages.     

Cibarial morphology in Psorophora Robineau-Desvoidy subgenera (Diptera: Culicidae)

We describe the cibarial morphology in eight Psorophora species Robineau-Desvoidy: Ps. (Grabhamia) cingulata (Fabricius), Ps. (Gra.) confinnis (Lynch Arribálzaga), Ps. (Janthinosoma) ferox (Humboldt), Ps. (Jan.) albipes (Theobald), Ps. (Jan.) cyanescens (Coquillett), Ps. (Psorophora) lineata (Humboldt), Ps. (Pso.) cilipes (Fabricius), y Ps. (Pso.) ciliata (Fabricius). The species belonging to subgenus Grabhamia Theobald are characterized by palatal papillae in central position and the presence of cibarial armature. The teeth in Ps. cingulata are equal meanwhile in Ps. confinnis the internal row is spatulate with apex denticulate. In Janthinosoma Lynch Arribálzaga we observed six palatal papillae (the fore pair with less size to others) and armature absent, instead we observe small spicules toward posterior plate: abundant in Ps. ferox, and few in Ps. albipes and Ps. cyanescens. The subgenus Psorophora presents four equal size palatal papillae, cibarial armature absent, also distinctive number of trichoid sensilla (12-17), in comparison to other two subgenera (5-10). We suggest to include those diagnostic characters in the future taxonomic and systematic studies in the genus Psorophora.     

Comparative morphology of the pyloric armature of adult mosquitoes (Diptera: Culicidae)

The structure of the pyloric armature, hypothesized to aid in blood-meal digestion or parasite resistance, was compared quantitatively among the following 8 species in 5 genera of adult mosquitoes from the southeastern United States: Aedes albopictus, Aedes japonicus, Aedes triseriatus, Anopheles punctipennis, Culex pipiens s.l., Culex restuans, Orthopodomyia signifera, and Toxorhynchites rutilus. Females differed significantly among species in the structure of spines composing the armature, with Aedes spp. forming one general group, Culex spp. another, and An. punctipennis and Or. signifera a third. Relationships of species based on structural characters of the armature were consistent with recent culicid phylogenies. Although pyloric armature has been noted in mosquitoes and other insects, this is the first quantitative investigation of the mosquito pyloric armature.     

Phlebotomine sandflies from Madagascar (Diptera: Psychodidae). IV--Description of Sergentomyia (Rondanomyia) goodmani n. sp. Reinstatement of the subgenus Rondanomyia Theodor

This work is the fourth related to species recently described from Madagascar. The authors describe Sergentomyia goodmani on females and males. The female has tubular spermathecae with internal spines. It has an aspect, in Canada balsam, of transversally striped spermatheca, without being completely segmented. The spermathecal ducts share a proximal common part. The pharynx is narrow. The cibarial armature is comb-like. Based on these characters, the authors consider that S. goodmani belongs to the subgenus Rondanomyia. They reinstate this subgenus and consider Neophlebotomus sensu Lewis, 1977 as invalid. Considering Grassomyia as a genus, this is the first record of Sergentomyia in Madagascar.     

Morphological fine tuning of the feeding apparatus to proboscis length in Hesperiidae (Lepidoptera)

The form and function of the hesperiid feeding apparatus was studied in detail. The butterflies in the family Hesperiidae are of particular interest because the longest proboscis ever recorded in Papilionoidea was found in the Neotropical genus Damas. We focused on the functional morphology by comparing proboscis morphology as well as size and composition of both the stipes pump and the cibarial suction pump in skippers with short and extremely long proboscis. Results revealed that all studied Hesperiidae have the same proboscis micromorphology and sensilla endowment regardless of the proboscis length. However, the numbers of internal muscles of the proboscis, the morphology of the stipes pump as well as the pumping organs for nectar uptake are related to the proboscis length. We conclude that the low number of tip sensilla compared to proboscis length is responsible for remarkably longer manipulation times of long‐proboscid species during flower visits. The organs for proboscis movements and nectar uptake organs are well tuned to the respective proboscis length and are accordingly bigger in species with a proboscis that measures twice the body length.     

中国云南蚁蛛属一新种记述(蜘蛛目,跳蛛科)

记述了产于我国云南的蚁蛛1新种:环蚁蛛 Myrmarachne circulus sp.nov.,标本采自云南勐腊,保存在湖南师范大学生命科学院,量度单位为mm.新种与黄蚁蛛Myrmarachne plataleoides(Cambridge,1869)相似,但有以下区别:1)雄蛛螯肢外侧近平直,后者呈"P"形;2)生殖球肥大,后者较细小;3)贮精管粗大,半环形,后者较细小,呈"S"形;4)兜位于外雌器中下部,后者位于下部.     

The status of Simulium oyapockense and S.limbatum as vectors of human onchocerciasis in Brazilian Amazonia

In an attempt to explain the current distribution of onchocerciasis in the forests of northern Brazil (Moraes et al., 1979, 1986), and its potential for dispersal to other areas, this study compares the vector status of Simulium oyapockense Floch and Abonnenc, 1946 in both a hypoendemic and an onchocerciasis free area with that of S. limbatum Knab, 1915 in the latter area. Both species allowed the full development of Onchocerca volvulus (Leuckart) to the infective L3 stage after experimental infection with microfilariae. Their vector competence was significantly lower than for other efficient vector species in South America and Africa because of the lethal effect of the cibarial armature on ingested microfilariae. The low vector capacity of S. oyapockense, together with the low prevalence and intensity of infection of O. volvulus, probably explains why onchocerciasis has not significantly increased in intensity over the last 10 years in the hypoendemic part of the Amazonian focus. Omnipresence of both vector species in the adjacent savanna region, however, could facilitate the spread of onchocerciasis if human population movements continue from the hyperendemic part of the onchocerciasis focus.     

雌蚊翅振音及其在蚊虫防治中的应用

蚊虫飞翔时 ,翅上下拍打会形成连续的翅振音。雌蚊翅振音频率会随蚊种、蚊体长和日龄及环境温度而变化 ,一般在 3 0 0～ 5 0 0Hz之间。同种个体间翅振音频率变化较小 ,常在平均频率± 5 0Hz范围内。雄蚊只对基本频率的雌蚊翅振音起反应 ,雌蚊翅振音的偶然变化不会降低其对雄蚊的引诱力。雄蚊对雌蚊翅振音具有敏感反应的主要原因是其听觉器官对雌蚊翅振音形成了良好的适应性。因此 ,许多蚊虫研究者希望利用雌蚊翅振音来防治蚊虫。因该方法对环境安全 ,在今后蚊虫防治中其重要性将会日益显现。     

中国湖北赵氏合跳蛛记述(蜘蛛目,跳蛛科)

记述了产于我国湖北的跳蛛l新种：赵氏合跳蛛Synagelides zhaoi sp.nov。新种的主要特征及其与近似种的区别在文中都有详细的论述,量度单位为mm。     

Why are there no small species among xylem-sucking insects?

Xylem-sucking herbivores must cope with negative tension and extremely low nutrient concentration of xylem fluid. We test the hypothesis that the energetic cost of xylem fluid extraction grows with decreasing body size, as small species have relatively high metabolic rates and small feeding apparatus. The suction pressure gradient needed for feeding (P), calculated using Poiseuilles Law, and the cibarial pump load (L), estimated as xylem fluid volume per unit volume of cibarial muscles, were used to quantify energetic costs associated with feeding. Interspecific relationships between body size and frontoclypeus (cibarial pump) volume, proboscis length and food canal diameter were quantified using the structural relations model and model I (ordinary) regressions applied on species as data points (phylogeny ignored), and on independent (intrageneric) contrasts (taxonomy used as a surrogate of phylogeny). All the dimensions of feeding apparatus changed approximately isometrically with body volume. In consequence, the suction pressure gradient P (body volume)–0.21, and the cibarial pump load L (body volume)–0.17. These relationships result in an allometric change in energetic costs associated with xylem feeding. Energy needed to overcome the resistance of feeding apparatus (P) becomes negligible for any species longer than about 8mm, and there is an important decrease in the L values in species over about 17mm in body length. These allometric trends can result in large species having a wider range of potential (energetically profitable) host plants than small species. Analysis of body size distributions in xylem-feeding insects, which all belong to the Auchenorrhyncha (Hemiptera), showed that xylem feeders tend to be larger than phloem feeders, especially in terms of the minimum body size. Two evolutionary transitions from phloem to xylem feeding in Hemiptera were associated with an increase in the minimum body size. A possibility that the evolution of minimum body size in xylem feeders is energetically constrained is discussed.     

Description of a new trypanorhynch species (Cestoda) from Indonesian Borneo, with the suppression of Oncomegoides and the erection of a new genus Hispidorhynchus

A new species of Oncomegas Dollfus, 1929 is described from the cowtail stingray, Pastinachus atrus (Macleay), collected in the Makassar Strait, Indonesian Borneo. Oncomegas trimegacanthus n. sp. possesses 2 oval bothria, gland cells within the bulbs, prebulbar organs, a distinctive basal armature with a single macrohook on the bothrial surface of the asymmetrical basal swelling, and a heteroacanthous, heteromorphous metabasal armature with 10 hooks per principle row. It differs from congeners by its possession of additional enlarged hooks at the base of the tentacle. Because of apparent morphological similarities, we suppress the genus Oncomegoides Beveridge & Campbell, 2005 with Oncomegas, and place the type and only species, Oncomegoides celatus Beveridge & Campbell, 2005 , within Oncomegas as Oncomegas celatus n. comb. Three species of Oncomegas , namely, Oncomegas paulinae Toth, Campbell & Schmidt, 1992, Oncomegas australiensis Toth, Campbell & Schmidt, 1992, and Oncomegas aetobatidis Campbell & Beveridge, 2009, differ from other species, possessing testes posterior to the ovary and a metabasal armature consisting of tiny, relatively homeomorphous hooks, with more than 14 hooks per principle row. Based on these morphological differences, a new genus, Hispidorhynchus n. gen., is erected, with Hispidorhynchus australiensis n. comb. as the type species.     

Gustatory feedback affects feeding related motor pattern generation in starved 3rd instar larvae of Calliphora vicina

Gustatory feedback allows animals to distinguish between edible and noxious food and adapts centrally generated feeding motor patterns to environmental demands. In reduced preparations obtained from starved Calliphora larvae, putatively appetitive (ethanol), aversive (sodium acetate) and neutral (glucose) gustatory stimuli were applied to the anterior sense organs. The resulting sensory response was recorded from the maxillary- and antennal nerves. All three stimuli increased the neural activity in both nerves. Recordings obtained from the antennal nerve to monitor the activation pattern of the cibarial dilator muscles, demonstrated an effect of gustatory input on the central pattern generator for feeding. Ethanol consistently enhanced the rhythmic activity of the CDM motor neurons either by speeding up the rhythm or by increasing the burst duration. Ethanol also had an enhancing effect on the motor patterns of a protractor muscle which moves the cephalopharyngeal skeleton relative to the body. Sodium acetate showed a state dependent effect: in preparations without spontaneous CDM activity it initiated rhythmic motor patterns, while an ongoing CDM rhythm was inhibited. Surprisingly glucose had an enhancing effect which was less pronounced than that of ethanol. Gustatory feedback therefore can modify and adapt the motor output of the multifunctional central pattern generator for feeding.     

中国蛤莫蛛属一新种记述(蜘蛛目,跳蛛科)

记述了采自中国湖南张家界境内的蛤莫蛛属Harmochirus 1新种:松林蛤莫蛛Harmochirus pineus sp.nov..新种与鳃蛤莫蛛Harmochirus brachiatus(Thorell,1877)相似,但有以下几点不同:1)新种后齿堤一齿不分叉,后者分两叉;2)两者雄蛛第Ⅰ步足胫节刺着生位置有区别,新种的3对胫节刺着生于胫节远端2/3下方,后者3对胫节刺等距离着生于胫节下方;3)新种雌蛛Ⅰ胫节背面无羽状毛;4)二者腹部背面斑纹有明显区别.     

External sense organs in freshwater oligochaetes (Annelida, Clitellata) revealed by scanning electron microscopy

Freshwater oligochaetes have at least two kinds of external sense organs: multiciliate organs of short cilia (also present in earthworms) and sense organs with one to three long cilia (unknown in earthworms and possibly acting as rheoreceptors). Ciliate sense organs of freshwater oligochaetes are distributed over their entire body surface, including the clitellum. They are scattered on the prostomium and pigidium and are arranged into a transversal chaetal row and dispersed or forming a few other discrete transversal rows on chaetal segments. Three species display very prominent sense organs (sensory buds in Protuberodrilus tourenqui and papillae in Ophidonais serpentina and Spirosperma velutinus). The number of cilia per organ at the prostomium of freshwater families appears to be fewer than that of terrestrial ones. It is suggested that the total number of cilia at the prostomium of the freshwater species could be related to their habitat, evolving from an epibenthic to an endobenthic way of life.     

Diversity,distribution, abundance,and feeding pattern of tropical ornithophilic mosquitoes

Bird–biting mosquitoes act as bridge vectors of diverse pathogens of emerging infectious diseases. In this study, we report for the first time the abundance, diversity, distribution, and feeding pattern of bird‐biting mosquitoes on an island where avifaunal diversity is rich. Monthly mosquito collections were done at six different habitats in three different climatic zones using bird‐baited traps over a year. Collected mosquitoes were identified using morphological and molecular tools. A total of 2,655 bird‐biting mosquitoes of eight genera and 25 species were identified. Of these, 52% were Culex species, which represents 35% of the Culex species in the country. The most abundant species were Culex sitiens, Cx. pseudovishnui, Cx. nigropunctatus and Cx. quinquefasciatus, whereas the latter two were common to all habitats. The highest abundance was reported in lowland forests (49.6%), while it was lowest in highland forests (22.3%). Highest species similarity was reported from highland forests. Seasonal variations of the most abundant species were significantly different in selected habitats (p< 0.05). Two distinct biting peaks were identified, from 06:00 to 21:00 and 22:00 to 02:00. The biting nature of identified ornithophilic mosquitoes suggests the potential vector status of these mosquitoes.