Internal reproductive organs of the female humpbacked fly,Megaselia scalaris Loew (Diptera : Phoridae)

The female reproductive system of the humpbacked fly Megaselia scalaris Loew (Diptera : Phoridae) was examined in whole mount preparations and serial sections. The system includes 2 ovaries, paired lateral oviducts, a common oviduct, and a genital chamber, opening externally through a gonopore, anteriad and ventrad to the anus. The ducts of the 2 accessory glands open independently into the dorsal region of the genital chamber. The terminal duct of a 2-armed spermatheca joins the right posterior and ventral wall of the genital chamber, immediately inside the gonopore. Passing dorally, the spermathecal duct lies immediately ventral to the duct of the right accessory gland. A short distance posteriad, it divides into two branches, each supplying an arm of the spermatheca. The genital chamber extends both anteriorly and posteriorly from its junction with the common oviduct, creating anterior and posterior compartments. In the right lateral wall of the genital chamber, a distinctive loop-shaped thickening (plate) resembles a darkened thread when it is observed through the integument. Features likely to have taxonomic utility include the posterior and ventral location of the terminal portion of the spermathecal duct; and the asymmetrically arranged, loop-shaped plate.     

Observations on first and second-instar larvae of Megaselia scalaris (Loew) (Diptera: Phoridae).

The ultrastructure of the first and second-instar larvae of Megaselia scalaris (Loew) was studied using scanning electron microscopy (SEM). Significant changes in morphological features were observed in the anterior and posterior spiracles, but only minimal changes in the labium and mouthhooks were seen. The ultrastructure of M. scalaris larvae not only provides chronological transformation of their larval instars, but it can also be used to explain their feeding behavior and mode of respiration. In addition, morphological structures useful for specific identification of first or second-instar larvae collected from human corpses may be used in forensic investigations.     

Lygus hesperus （Heteroptera： Miridae） tolerates high concentrations of dietary nickel

Nickel hyperaccumulator plants contain unusually elevated levels of Ni （〉 1 000 μg Ni/g）. Some insect herbivores, including Lygus hesperus （Western tarnished plant bug）, have been observed feeding on the California Ni hyperaccumulator Streptanthus polygaloides. This bug may be able to utilize S. polygaloides as a host either through its feeding behavior or by physiological tolerance of Ni. This experiment determined the Ni tolerance of L hesperus by offering insects artificial diet amended with 0, 0.4, 1, 2, 4.5, 10, 20 and 40 mmol Ni/L and recording survival. Survival varied due to Ni concentration, with diets containing 10 mmol Ni/L and greater resulting in significantly lower survival compared to the control （0 mmol Ni/L） treatment. Insects tolerated diet containing as much as 4.5 mmol Ni/L, a relatively elevated Ni concentration. I conclude that L hesperus can feed on S. polygaloides because it is Ni-tolerant, probably due to physiological mechanisms that provide it with resistance to plant chemical defenses including elemental defenses such as hyperaccumulated Ni.     

中国海南异蚤蝇属一新种记述(双翅目:蚤蝇科)

五指异蚤蝇Megaselia wuzhiensis,新种（图1～3） 雄性：额宽0．42mm,黑色,稀布细毛,纵沟细。触角上鬃4根,下对稍短;上对和下对间距分别是额宽的1／4和1／6。前额间鬃低于前额眶鬃及上触角上鬃,距眼缘和纵沟的距离比为1：3～1：2。后额间鬃低于后额眶鬃,四根鬃等距排列。触角第三节黑褐：芒亚端生,具微毛。下颚须黄色,具鬃5～7根。胸黑色。背中鬃2根;小盾片鬃2根,小毛2根：中侧片具毛,缺单鬃。翅长2．6mm。前缘脉指数0．53,各段比2．6：2．9：1,纤毛（最长）0．：24mm。腋区鬃3～6根。平衡棒黄褐色。足褐色,前足胫节0．68mm,跗节细长,各节长大于宽。中足胫节栅毛列伸达胫节端部1／5;后背纤毛7～9根。前背纤毛弱。后足股节1．2mm,腹缘细毛8～12根。胫节栅毛列完整,后背纤毛9～11根,强大：缺前背纤毛。腹部暗黑。背板Ⅱ和Ⅵ较长,其余背板近等长。背板稀被毛,两侧和后缘较多。尾器黑褐色,生殖背板两侧中部具鬃状毛;端部具小毛。肛管黄褐色。体长2．13～2．38mm。 正模：♂,海南五指山,1992—Ⅳ-16,刘广纯、王敏采：副模：5♂♂,同正模。 本种与缅甸产的M.atricornis Beyer相似,但后者前缘脉第二段短于第一段,额前侧鬃低于上触角上鬃。新种模式标本存于沈阳大学生物与环境工程学院标本室。     

中国异蚤蝇属一新种及二新记录种记述(双翅目:蚤蝇科)

A new Megaselia species: Megaselia angustirostris Fang & Liu, sp. nov., is described and illustrated and two species of the genus, M. nigra (Meigen) and M. albicaudata (Wood), are reported for the first time from China. The type specimens are deposited in College of Biological and Environmental Engineering, Shenyang University.     

Scuttle flies (Diptera: Phoridae) from Ardabil province in Iran,with description of a new species of Megaselia Rondani

our named species of scuttle flies were collected from Ardabil province-Iran, during 2013–2014. A new species of the genus Megaselia Rondani 1856, M. ardabilensis n. sp., is described from the region and Megaselia producta (Schmitz) is recorded from the country for the first time. Geographical distributions and supplementary figures are given.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:B28C521B-2BFE-44F3-9041-1656341F29B6     

A new species group in Megaselia,the lucifrons group,with description of a new species (Diptera,Phoridae)

With 1,400 described species, Megaselia is one of the most species-rich genera in the animal kingdom, and at the same time one of the least studied. An important obstacle to taxonomic progress is the lack of knowledge concerning the phylogenetic structure within the genus. Classification of Megaselia at the level of subgenus is incomplete although Schmitz addressed several groups of species in a series of monographs published from 1956 to 1981. Another problem is the lack of molecular phylogenetic analyses to support morphology-based conclusions. As a contribution towards addressing these problems, we here circumscribe a previously unrecognized monophyletic lineage of Megaselia consisting of species similar to Megaselia lucifrons. We base this taxonomic decision on morphological study of an extensive phorid material from Sweden, complemented by molecular analyses of select exemplars using two markers (COI and 28S). We name the clade the lucifrons species group, and show that it contains three distinct species. Our results also demonstrate that Megaselia subnitida Lundbeck, 1920, previously treated as a synonym of Megaselia lucifrons Schmitz, 1918, is a separate species, and we remove it from synonymy. The third species in the group was previously unknown; we describe it here as Megaselia albalucifrons sp. n.     

Control of the mushroom pests Lycoriella auripila (Diptera: Sciaridae) and Megaselia halterata (Diptera: Phoridae) by Steinernema feltiae (Nematoda: Steinernematidae) in field experiments

The nematode Steinernema feltiae (Nematoda: Steinemematidae) was tested for its ability to control two main mushroom pests i.e. the sciarid Lycoriella auripila (Diptera: Sciaridae) and the phorid Megaselia halterata (Diptera: Phoridae) in growing-rooms filled with spawned compost. A clear difference between female and male sciarid control was observed. A nematode application 1 day after casing preceded by an application 1 day before casing on the compost caused an almost complete control (97%) of the F1-generation of female sciarids. The F2-generation of females was similarly controlled (95%) by an application 7 days after casing. A dosage of 1 × 10⁶nematodes m^-2was found to be equally effective as higher dosages. Diflubenzuron remained active throughout entire the cropping period with high sciarid mortality rates varying from 72% to 99%. Phorid control was variable and seemed to depend on the presence of sciarids. In one occasion the control rate of F2-generation phorid larvae was 75% and was possibly caused by the presence of new infective juvenile nematodes recycled in F2-generation sciarid larvae. Diflubenzuron did not significantly reduce phorid numbers.     

Species richness estimations of the megadiverse scuttle fly genus Megaselia (Diptera: Phoridae) in a wildfire‐affected hemiboreal forest

Abstract The species richness of the scuttle fly (Diptera: Phoridae) genus Megaselia was estimated by various non‐parametric estimators from EstimateS, Species Prediction And Diversity Estimation (SPADE) and Ws2m, based on material from a Swedish hemiboreal forest area recently affected by major wildfires, Tyresta National Park and Nature Reserve (TNPNR), south of Stockholm. A total of 21 249 individuals were collected in Malaise traps, of which males constituted 16 976 and females 4 273. The analysed dataset represents 37 samples containing 18 549 specimens sorted into 330 species (184 described, 146 are either undescribed or of unsettled taxonomic status). It was not possible to estimate the total species richness using all samples due to heterogeneity caused by inclusion of different communities and temporal incoherencies between samples within and between years. Even with material obtained from a sampling program that was not designed for species richness estimates, it was possible to obtain reliable results when sample heterogeneity was minimized. By dividing the data into community‐specific datasets – for bog, forest and wildfire – it was possible to obtain asymptotic curves for the smaller of the two wildfire datasets. A total estimate of 357–439 (95% CI) was attained by using the smaller wildfire dataset and adding the 85 unique species from the samples not included in the estimation analysis. TNPNR has one of the richest known scuttle fly communities in Europe, consisting of almost 50% of the currently named Megaselia species; 48 of these species are reported as new records for Sweden in this study.     

The structure and surface properties of the eggshell of Megaselia imitatrix Borgmeier (Diptera, Phoridae) in relation to the respiration of the embryo

The role of the chorion in the mechanism of respiration is examined for the egg of Megaselia imitatrix. An air layer in the chorion is not essential for respiration, and oxygen can be absorbed through a hydrophilic pathway in the chorion by diffusion from the surrounding water. A model based on the diffusion of oxygen through the surface layer of the water down to the depth of the egg is proposed and presented in detail.     

Copper kinetics and hepatic metallothionein levels in the frog Rana ridibunda, after exposure to CuCl2

Adult female frogs Rana ridibunda were exposed to 50 and 100 ppm of Cu (as CuCl₂) dissolved in water for 5, 15 and 30 days. We measured the Cu content in the liver, kidneys, ventral skin, and large intestine. Hepatic metallothionein (MT) was also measured and we identified by elution the type of proteins bound to copper. Gross morphological characteristics of the frogs were not affected by Cu accumulation. Cu uptake took place first across the skin, then accumulated first in the large intestine, and then in the liver which was continuously accumulating Cu at all exposure concentrations and times. The highest concentration of the metal was recorded in the kidneys at 30 days and 100 ppm exposure. It appears that the kidneys act as the secondary route of Cu detoxification, probably after a Cu overload of liver. The concentration of hepatic MT increased with the increase of Cu concentration in liver at the 5^th and 15^th day of exposure but we observed a decrease by the end of the experiment. Cu was observed in the MT-fraction, and in the high-molecular weight protein fraction.     

取食重金属铜对棕尾别麻蝇亲代及子代生长发育与繁殖的影响

为了评估取食含重金属铜饲料对棕尾别麻蝇Boettcherisca peregrine亲代及子代的生长发育与繁殖的影响,在室内给棕尾别麻蝇初产幼虫饲喂含不同浓度（200, 400,800和1 600 µg/g）Cu²⁺的饲料直至化蛹,并对亲代和子代的生长发育和繁殖有关指标进行了观察和分析。结果表明：低浓度的Cu²⁺（200 µg/g）对其体重和体长起促进作用,但对幼虫历期、化蛹率、蛹历期、羽化率、性比、交配率和产仔量无显著作用;较高浓度的Cu²⁺ 则有抑制作用,且Cu²⁺处理浓度越高,亲代幼虫、蛹和雌雄成虫的体重越轻,幼虫和蛹的体长越短,化蛹率、羽化率、交配率和产仔量越低,幼虫历期和蛹期越长,成虫寿命越短。但Cu²⁺处理对成虫性比则无显著的影响。相比之下,经Cu²⁺处理后雌虫所产的子代若不再经Cu²⁺处理,其子代生存、生长发育与繁殖则基本不受影响,说明Cu²⁺对亲代的影响不能遗传至子代。此外,还探讨了该蝇亲代与子代体内Cu²⁺含量在其变态过程中的变化。     

重金属Cd2+对棕尾别麻蝇血细胞数量、包囊作用和形态结构的影响

为了揭示重金属对昆虫细胞免疫的影响及其机理,本文采用血细胞计数、台盼蓝染色、延展与包囊率测定, 以及显微与超微结构观察等方法,以经重金属Cd²⁺（浓度为150 μg/g）处理的棕尾别麻蝇Boettcherisca peregrina及其对照为研究对象,分别测定了处理组与对照组血细胞的数量与存活率、延展与包囊率,观察其形态结构,并比较了两组间的差异。结果表明： 棕尾别麻蝇初产幼虫经连续喂饲含Cd²⁺的饲料24,48,72和96 h后,与对照相比其血细胞总数和存活率显著下降,而血细胞的延展率和包囊作用的显著下降则分别出现于取食72和48 h之内,此后则下降不显著;由Cd²⁺处理幼虫发育形成蛹的血细胞包囊作用也显著低于对照。形态结构观察结果表明,Cd²⁺处理对幼虫的原血细胞、浆血细胞、颗粒血细胞和类绛色血细胞的显微形态影响不大,但可导致部分浆血细胞不能产生伪足;但均能导致各类血细胞的超微结构发生不同程度的变化,其中主要变化包括：细胞膜受损或破裂,染色质呈现凝聚, 线粒体和内质网等细胞器明显减少,以及胞质内出现空囊泡。结果说明重金属Cd²⁺对棕尾别麻蝇的血细胞可具有毒害作用。     

重金属在拟水狼蛛体内的分布及对其体内抗氧化酶活性的影响

为了探明重金属在拟水狼蛛Pirata subpiraticus体内的分布及对其体内抗氧化酶活性的影响,本研究于2009年6月在河南南阳地区5种不同生境下,共采集50份土壤样本和300头拟水狼蛛样本,采用原子吸收光谱法测定了5种不同生境下雄雌拟水狼蛛体内重金属的分布、GSH含量以及GST,CAT和SOD的活性。结果表明：5个采集样点（S1, S2, S3, S4和S5） 拟水狼蛛体内重金属（Cd,Pb,Cu和Zn）的含量差异显著（P<0.05）。同一地点拟水狼蛛体内重金属（Cd,Pb,Cu和Zn）的含量不同身体部位差异显著（P<0.05）,头胸部>足部>腹部,同一地点雄性拟水狼蛛重金属含量显著高于雌性（P<0.05）。在重金属胁迫下,重金属含量高（S1,S2,S3和S4）的拟水狼蛛体内GSH 含量显著高于参照组（S5）,雄性GSH 含量高于雌性（P<0.05）。对于不同身体部位,GSH 含量差异显著,头胸部GSH 含量最高,其次为足部,腹部含量最低;GSH 含量与重金属含量显著正相关（r2=0.9854,P<0.05）。对于GST,CAT和SOD,重金属含量高则酶活性低,雄性酶活性显著低于雌性,不同身体部位酶活差异不显著;GST,CAT和SOD酶活性与重金属（Cd和Pb或者Pb）含量显著负相关。因此检测拟水狼蛛不同身体部位的酶活性变化就可知环境中重金属的污染程度,拟水狼蛛可以作为重金属污染的重要监测指示生物。     

Larval mouthpart deformities in Procladius paludicola Skuse (Diptera: Chironomidae) from the Murray and Darling Rivers,Australia

A high incidence of ligula (mouthpart) deformities is reported for the larvae of Procladius paludicola Skuse (Diptera: Chironomidae) collected from sites on the Murray and Darling Rivers, Australia. This is the first report of deformities in Australian freshwater insects, and is discussed in relation to known toxic pollutants within the catchment.     

河南南阳不同生境土壤重金属含量及其对拟水狼蛛生物学特性的影响

为了探明重金属含量对拟水狼蛛Pirata subpiraticus生物学特性的影响, 本研究于2008年7月在河南南阳地区5种不同生境下, 共采集50份土壤样本和150头拟水狼蛛样本, 采用原子吸收光谱法测定了5种不同生境下雌拟水狼蛛体内重金属含量, 并测定了雌蛛头胸甲宽、体重、卵袋重量、卵数目和卵体积等生物学指标。结果表明：不同样点拟水狼蛛重金属含量与土壤重金属含量显著正相关, 4个重金属污染区与宝天曼自然保护区（Baotianman, BTM）拟水狼蛛体内Cd、Cu和Zn的含量差异极显著(P<0.001), 桐柏铜矿（Tongbai Tongkuang, TBTK）和南阳油田(Nanyang Youtian, NYYT) 的Pb含量与BTM的差异极显著(P<0.001), 主成分分析表明Cd、Cu和Zn是反应重金属污染的主要指标。在重金属胁迫下, 4个重金属污染区与保护区的拟水狼蛛头胸甲宽、雌体重量、卵袋重量、卵数目和卵体积差异均达到极显著（P<0.001）或显著水平（P<0.05）, 主成分分析表明背胸甲宽、卵袋重量和卵体积是重要生物学指标。 拟水狼蛛的背胸甲宽、卵袋重量和卵的体积与重金属含量显著相关, 重金属含量高的地方拟水狼蛛背胸甲宽较小, 雌性体重、卵袋重量和卵数目较小, 卵的体积大, 因此说明拟水狼蛛处在逆环境中时, 动物为保持总的繁殖力不变的前提下, 后代个体的大小与数目间满足某种平衡, 即达到协同进化的目的, 拟水狼蛛可以作为重金属污染的监测指示生物。     

Seasonal dynamics and larval drift of Chironomus riparius (Diptera) in a metal contaminated lowland river

Chironomus riparius is one of the insect species which inhabit polluted rivers in large densities, indicating a high adaptive capacity. Previous studies showed that this capacity is expressed by the occurrence of adapted strains in metal polluted rivers. Differences in life history between metal-exposed and non-exposed midges have been demonstrated in laboratory experiments, and therefore a comparative field study of seasonal dynamics was carried out at two metal polluted sites and one reference site. Just downstream from a massive metal discharge, seasonal dynamics were almost identical to the upstream reference site. Circa four generations per year were produced. Further downstream, lower larval densities were recorded, especially during the second half of the sampling period. The influx of upstream C. riparius larvae into polluted sites was estimated by measuring larval drift just upstream from the point source of metal contamination and indicated a massive input to the standing stock downstream. It is concluded that drift of non-tolerant larvae is dominating the seasonal dynamics of midges downstream. Accordingly, genetic uniformity of chironomids inhabiting upstream and downstream sites is expected most of the time. However, research performed during the last decade, demonstrated that genetically adapted strains of C. riparius may develop at certain stages in the seasonal cycle. However, a stable metal-adapted C. riparius population at the first downstream site, is most likely present on rare occasions only.