Immature stages of the bee fly Ligyra satyrus (F.) (Diptera: Bombyliidae): A hyperparasitoid of canegrubs (Coleoptera: Scarabaeidae)

We describe the third- and fourth-instar larva, pupa and biology of the hyperparasitoid bee fly Ligyra satyrus (Fabricius). The larval and pupal morphology of the bee fly is typical for members of the subfamily Anthracinae. The bee fly larvae are found inside cocoons of the scoliid Campsomeris tasmaniensis Saussure, an external parasite of canegrubs (Coleoptera: Scarabaeidae) in sugarcane fields at Ayr and Bundaberg, Queensland. Ligyra satyrus has been recorded attacking only C. tasmaniensis . Ligyra and its relatives are all parasites of predatory and parasitic, ground-nesting aculeate Hymenoptera such as Sphecidae, Pompilidae, Tiphiidae and Scoliidae. Larval morphology of the hyperparasite is similar to other ectoparasitic Bombyliidae and pupal morphology is compared to that of species in the same and related subfamilies. Rates of hyperparasitism at Gordonvale reported in the early 1900s are relatively high, but our results show that currently they are very low at Ayr and Bundaberg. These results suggest that the impact of the bee fly on natural control of the canegrubs by scoliids varies considerably.     

Early collapse of Vespa simillima (Hymenoptera, Vespidae) colonies in central Japan

During the past 15 years in the Ina Valley, Japan, mature fifth instar larvae of the yellow hornet, Vespa simillima, have been occasionally ejected from colonies during September. During 2005, this unusual behavior was particularly widespread, and collection of several V. simillima colonies confirmed that very few fifth instar larvae were present. When compared with an average colony, constructed from 41 colonies collected 20 years previously, colonies in 2005 had 80% fewer fifth instar larvae, despite queen egg‐laying rates remaining similar. It may be that the amount of food provided to the larvae by workers is less than the amount of larval secretions received by workers, which is causing the larvae to become emaciated and preventing them from pupating. This phenomenon normally occurs naturally at the end of the colony cycle in November, when prey abundance decreases and larval secretions or other sources of carbohydrates, for example from ripe fruit, tree sap, or aphid secretions, are needed by sexuals to build up fat reserves. However, another possibility is that the unexplained appearance of this phenomenon in September, which is causing colonies to collapse without producing any or very few sexuals, is due to foragers feeding the larvae prey that are contaminated with insect growth regulators, via pesticides, which are known to prevent successful pupation.     

Anatomical and functional characterisation of the stomatogastric nervous system of blowfly (Calliphora vicina) larvae

The anatomy and functionality of the stomatogastric nervous system (SNS) of third-instar larvae of Calliphora vicina was characterised. As in other insects, the Calliphora SNS consists of several peripheral ganglia involved in foregut movement regulation. The frontal ganglion gives rise to the frontal nerve and is connected to the brain via the frontal connectives and antennal nerves (ANs). The recurrent nerve connects the frontal- to the hypocerebral ganglion from which the proventricular nerve runs to the proventricular ganglion. Foregut movements include rhythmic contractions of the cibarial dilator muscles (CDM), wavelike movements of crop and oesophagus and contractions of the proventriculus. Transections of SNS nerves indicate mostly myogenic crop and oesophagus movements and suggest modulatory function of the associated nerves. Neural activity in the ANs, correlating with postsynaptic potentials on the CDM, demonstrates a motor pathway from the brain to CDM. Crop volume is monitored by putative stretch receptors. The respective sensory pathway includes the recurrent nerve and the proventricular nerve. The dorsal organs (DOs) are directly connected to the SNS. Mechanical stimulation of the DOs evokes sensory activity in the AN. This suggests the DOs can provide sensory input for temporal coordination of feeding behaviour.     

Comparative analysis of the excretory-secretory proteome of the muscle larva of Trichinella pseudospiralis and Trichinella spiralis

The nematodes Trichinella spiralis and Trichinella pseudospiralis are both intracellular parasites of skeletal muscle cells and induce profound alterations in the host cell resulting in a re-alignment of muscle-specific gene expression. While T. spiralis induces the production of a collagen capsule surrounding the host-parasite complex, T. pseudospiralis exists in a non-encapsulated form and is also characterised by suppression of the host inflammatory response in the muscle. These observed differences between the two species are thought to be due to variation in the proteins excreted or secreted (ES proteins) by the muscle larva. In this study, we use a global proteomics approach to compare the ES protein profiles from both species and to identify individual T. pseudospiralis proteins that complement earlier studies with T. spiralis. Following two-dimensional gel electrophoresis, tandem mass spectrometry was used to identify the peptide spots. In many cases identification was aided by the determination of partial peptide sequence from selected mass ions. The T. pseudospiralis spots identified included the major secreted glycoproteins and the secreted 5'-nucleotidase. Furthermore, two major groups of T. spiralis-specific proteins and several T. pseudospiralis-specific proteins were identified. Our results demonstrate the value of proteomics as a tool for the identification of ES proteins that are differentially expressed between Trichinella species and as an aid to identifying key parasite proteins that are involved in the host-parasite interaction. The value of this approach will be further enhanced by data arising out the current T. spiralis genome sequencing project.     

松阿扁叶蜂越冬幼虫体内氨基酸含量的测定分析

本文测定了不同时期松阿扁叶蜂Acantholyda posticalis Matsumura越冬幼虫虫体、血淋。巴内氨基酸含量,并对影响幼虫抗寒的氨基酸进行了探讨。对越冬幼虫体内17种氨基酸的研究结果表明,从越冬初期至越冬期,氨基酸种类并没有发生变化,但各种氨基酸含量变化不同,丙氨酸、谷氨酸、脯氨酸、精氨酸和胱氨酸随着温度的下降呈增加趋势。幼虫虫体总氨基酸含量增幅最大的为丙氨酸,比越冬初期增加了28.8%,其次是脯氨酸、酪氨酸、苯丙氨酸,分别比越冬初期增加了9.4%、6.4%和5.4%,其他氨基酸增加不明显;幼虫血淋巴内游离氨基酸中的丙氨酸、胱氨酸和谷氨酸含量分别比越冬初期增加了94.6%、80.2%和19.6%。因此认为体内这些氨基酸含量的变化可能与低温抗寒密切相关。     

Larval Gnathostoma spinigerum Detected in Asian Swamp Eels,Monopterus albus,Purchased from a Local Market in Yangon,Myanmar

The present study was performed to determine the infection status of swamp eels with Gnathostoma sp. larvae in Myanmar. We purchased total 37 Asian swamp eels, Monopterus albus, from a local market in Yangon in June and December 2013 and 2014. All collected eels were transferred with ice to our laboratory and each of them was examined by the artificial digestion technique. A total of 401 larval gnathostomes (1-96 larvae/eel) were detected in 33 (89.2%) swamp eels. Most of the larvae (n=383; 95.5%) were found in the muscle. The remaining 18 larvae were detected in the viscera. The advanced third-stage larvae (AdL₃) were 2.3-4.4 mm long and 0.25-0.425 mm wide. The characteristic head bulb (0.093 × 0.221 mm in average size) with 4 rows of hooklets, muscular long esophagus (1.025 mm), and 2 pairs of cervical sacs (0.574 mm) were observed by light microscopy. The average number of hooklets in the 1st, 2nd, 3rd, and 4th rows was 41, 45, 48, and 51, respectively. As scanning electron microscopic findings, the characteristic 4-5 rows of hooklets on the head bulb, a cervical papilla, tegumental spines regularly arranged in the transverse striations, and an anus were well observed. Based on these morphological characters, they were identified as the AdL₃ of Gnathostoma spinigerum. By the present study, it has been confirmed for the first time that Asian swamp eels, M. albus, from Yangon, Myanmar are heavily infected with G. spinigerum larvae.     

Coding characters from different life stages for phylogenetic reconstruction: a case study on dragonfly adults and larvae,including a description of the larval head anatomy of Epiophlebia superstes (Odonata: Epiophlebiidae)

The exclusive use of characters coding for specific life stages may bias tree reconstruction. If characters from several life stages are coded, the type of coding becomes important. Here, we simulate the influence on tree reconstruction of morphological characters of Odonata larvae incorporated into a data matrix based on the adult body under different coding schemes. For testing purposes, our analysis is focused on a well‐supported hypothesis: the relationships of the suborders Zygoptera, ‘Anisozygoptera’, and Anisoptera. We studied the cephalic morphology of Epiophlebia, a key taxon among Odonata, and compared it with representatives of Zygoptera and Anisoptera in order to complement the data matrix. Odonate larvae are characterized by a peculiar morphology, such as the specific head form, mouthpart configuration, ridge configuration, cephalic musculature, and leg and gill morphology. Four coding strategies were used to incorporate the larval data: artificial coding (AC), treating larvae as independent terminal taxa; non‐multistate coding (NMC), preferring the adult life stage; multistate coding (MC); and coding larval and adult characters separately (SC) within the same taxon. As expected, larvae are ‘monophyletic’ in the AC strategy, but with anisopteran and zygopteran larvae as sister groups. Excluding larvae in the NMC approach leads to strong support for both monophyletic Odonata and Epiprocta, whereas MC erodes phylogenetic signal completely. This is an obvious result of the larval morphology leading to many multistate characters. SC results in the strongest support for Odonata, and Epiprocta receives the same support as with NMC. Our results show the deleterious effects of larval morphology on tree reconstruction when multistate coding is applied. Coding larval characters separately is still the best approach in a phylogenetic framework. © 2015 The Linnean Society of London     

中国亚洲玉米螟发育历期的地理变异

广布种昆虫可调节其生活史以适应栖息地的条件变化,如可以通过调节自身的生长发育和繁殖期,使其发生与栖息地的物候(如食料、气温和降雨等)同步,这对昆虫在栖息地的繁衍具有十分重要的意义。亚洲玉米螟Ostrinia furnacalis为玉米主要害虫,在中国从南到北都有分布,栖息地气候也不同,不同地理种群生活史发生了分化,如化性、临界光周期、滞育后羽化时间、体重和体型、繁殖力和抗寒力等均不同。然而该虫发育历期的地理变异尚未见系统报道。为此,详细比较了来自5个亚洲玉米螟不同地理种群即广西阳朔(YS)、江西南昌(NC)、山东泰安(TA)、河北廊坊(LF)和黑龙江哈尔滨(HEB)在20—31℃下卵、幼虫、蛹发育历期及其与栖息地纬度的关系。结果表明:不同温度下的不同地理种群的卵期不存在显著差异,在20、22和25℃下,卵期从南到北稍有延长,卵期与其栖息地纬度呈正相关;但在28℃下,不同地理种群的卵期基本相等,与纬度相关性不显著。在31℃下,不同地理种群的幼虫期不存在显著差异,而在其他温度下,不同地理种群的幼虫期存在显著差异;在22、25和28℃下,幼虫期与其栖息地纬度呈正相关,而在20和31℃下,幼虫期与其栖息地纬度呈负相关,在20、22和25℃下,最北的哈尔滨种群的幼虫期变幅不大,而其他4个种群的幼虫期随着温度的升高明显缩短。各地理种群20℃下的雌蛹、28℃下的雄蛹和31℃下的雌雄蛹期差异均不显著,其他雌或雄蛹期差异显著;各温度下的雌雄蛹期与其栖息地纬度存在正相关关系。这些研究结果揭示了广布种昆虫可以调节其自身发育历期以适应栖息地环境条件。     

Identification of Aedes albopictus larval index thresholds in the transmission of dengue in Guangzhou,China

Entomological indices have been used to quantitatively express vector density, but the threshold of larval indices of Aedes albopictus in dengue epidemics is still undefined. We conducted a case‐control study to identify the thresholds of Aedes albopictus larval indices in dengue epidemics. Two unit levels of analysis were used: district and street. The discriminative power of the indices was assessed by receiver operating characteristic (ROC) curves. The association between the entomologic indices and dengue transmission was further explored by a logistic regression model. At the district level, there was no significant difference in the Breteau index (BI) between districts that reported cases and those did not (t=0.164, p>0.05), but the Container index (CI) did show a significant difference (t=2.028, p<0.01). The AUC (Area Under the Curve) of BI, CI, and prediction value were 0.540, 0.630, and 0.533, respectively. Predicting at the street level, the AUC of BI, CI, and prediction values were 0.684, 0.660, and 0.685, respectively, and 0.861, 0.827, and 0.867 for outbreaks. BI=5.1, CI=5.4, or prediction value =0.491were suggested to control the epidemic efficiently with the fewest resources, where BI=4.0, CI=5.1, or PRE =0.483 were suggested to achieve effectiveness.