The karyotype of threeCryptochironomus species of West Siberia,USSR

Karyotype characteristics C. ussouriensis and two species of C. gr. defectus from the main and special lobe cells of the salivary gland are presented in detail in this paper for the first time. C. ussouriensis has two main chromosome markers, nucleolus in chromosome II and large Balbiani ring adjacent to the centromeric band in chromosome I. Balbiani ring is developed only in the main lobe cells and is absent in the special lobe cells. Each of two chromosomes of C. gr. defectus (C. obreptans) has a nucleolus and a Balbiani ring. They are well developed in the main lobe cells but in the special lobe cells the only nucleolus in chromosome II are functioning. The karyotype of C. gr. defectus (karyotype 1) is characterized with a large number of functionally active regions: nucleoli, BRs and puffs. Two BRs (in region 10 of chromosome I and in region 8 of chromosome III) functioning in the main lobe cells are absent in the special lobe cells. Since the pattern of nucleoli, BRs and puffs are of great importance in the karyotype characteristic of the different Cryptochironomus species, a comparative study of chromosomes from the different salivary gland lobes is needed.     

不同虫态及虫龄大草蛉与七星瓢虫之间的集团内互作

【目的】为明确新疆棉田棉蚜 Aphis gossypii 捕食性天敌之间的集团内捕食效应及其对蚜虫数量的控制作用。【方法】本研究以优势天敌昆虫大草蛉 Chrysopa pallens 和七星瓢虫 Coccinella septempunctata 为对象,以棉蚜为猎物,在温室中利用盆栽棉花,首先观察了2种天敌昆虫之间各虫态及虫龄配对的19个处理在无蚜植株上共存24 h后的存活数,然后观察了2种天敌昆虫配对处理下棉苗上棉蚜数量随时间的变化趋势。【结果】在无蚜棉株上2种捕食性天敌昆虫共存24 h后的存活结果表明：（1）在发育阶段相同的配对组合中,若是成虫则均存活,若是１龄幼虫则大草蛉存活较多,若是末龄幼虫则七星瓢虫存活较多;（2）在有卵的组配中,除七星瓢虫卵不被大草蛉成虫所捕食外,其他5个组配处理中卵均被捕食;（3）在有蛹的配对组合中,除七星瓢虫蛹被大草蛉末龄幼虫捕食外,其他处理下蛹均不被捕食;（4）在成虫与幼虫的配对组合中,七星瓢虫成虫捕食较多的大草蛉1龄幼虫,但不捕食大草蛉末龄幼虫,而大草蛉成虫与七星瓢虫1龄或末龄幼虫之间不发生捕食;(5）在不同龄期幼虫的配对组合中,大草蛉末龄幼虫捕食七星瓢虫1龄幼虫,而七星瓢虫末龄幼虫捕食大草蛉1龄幼虫。在有蚜植株上2种捕食性天敌共存对棉蚜数量具有不同的控制作用：（1）2种捕食昆虫的幼虫各自单独存在（对照）下,蚜虫密度随时间而降低;（2）大草蛉幼虫与七星瓢虫幼虫或成虫配对处理下,棉蚜密度随时间而增大;（3）大草蛉成虫与七星瓢虫幼虫或成虫配对处理下,棉蚜密度随时间而减小。【结论】研究结果说明,大草蛉与七星瓢虫之间存在集团内捕食,但２种天敌共存对棉蚜的控制作用取决于大草蛉虫态, 若大草蛉为幼虫,可使蚜虫密度增大,若为成虫,则使蚜虫密度减小。     

Effect of buprofezin on survival of immature stages of Harmonia axyridis, Stethorus punctum picipes (Coleoptera: Coccinellidae), Orius tristicolor (Hemiptera: Anthocoridae), and Geocoris spp. (Hemiptera: Geocoridae)

The effect of buprofezin, a chitin synthesis inhibitor, on development and survival of immature stages of Harmonia axyridis (Pallas), Stethortus punctum picipes Casey, Orius tristicolor (White), Geocoris pallens St?l, and Geocoris punctipes (Say), was examined in a series of laboratory bioassays. Very few H. axyridis larvae (3.1%) treated with buprofezin reached adulthood, although 65% of treated pupae emerged successfully. Buprofezin caused no mortality to eggs of S. punctum picipes but 71.1% of treated early instar larvae failed to complete development. Eighty percent of treated late instars and 92.3% of pupae produced viable adults. Early instar nymphs of O. tristicolor were unaffected by buprofezin, whereas 47.7 and 85% of G. punctipes and G. pallens nymphs, respectively, failed to complete development. Treated eggs of G. pallens hatched successfully. The use of buprofezin in integrated pest management in Washington state wine grapes is discussed.     

Characteristics of palinurids (Decapoda; Crustacea) in larval culture

Complete development of phyllosomas wasaccomplished in Palinurus elephas, Panulirus japonicus, Jasus edwardsii and J. verreauxi. Larval development differsbetween species in duration and moult frequency aswell as morphology. The highest percent survival was obtained during the phyllosoma stage forJ. verreauxi. Phyllosomas of P. elephas were the mostdifficult to cultureregardless of the fact that they hatch at arelatively advanced stage. Culture experiments werecarried out to improve the percent survival of P. elephas. First instars of P. elephasexhibited vigorous predation upon the larvae ofJapanese sandfish Arctoscopus japonicus.Duration of the first instar was shorter at 12.8days when reared at 18 °C and percent survival wasapproximately 30%. Better results were obtainedfor first instars cultured in water inoculated withChaetoceros sp. and fed enriched Artemianauplii. Phyllosomas of J. edwardsii and P. japonicus were cultured without particulardifficulty. Most distinguishing features of P. elephasis the heavily setose six or seven longspines on the distal edges of the scaphognathite ofthe second maxillae while only four long spines arefound in other species. These facts suggest thatphyllosomas of P. elephas are initiallyplankton feeders and from first instar becomerapacious predators.     

Weight gain of the predator Podisus distinctus (Heteroptera: Pentatomidae) with combinations of the preys Tenebrio molitor (Coleoptera: Tenebrionidae) and Musca domestica (Diptera: Muscidae)

Little is known about Podisus distinctus (Stal) (Heteroptera: Pentatomidae) one of the Asopinae species with good possibilities for mass rearing and releasing against defoliator caterpillars in eucalyptus reforested areas in Brazil. We evaluated the impact of prey combinations on weight of nymphs and adults of P. distinctus. The prey were Musca domestica L. (Diptera: Muscidae) and Tenebrio molitor L. (Coleoptera: Tenebrionidae). The experiment was developed under 25 +/- 0.5 degrees C, 60 +/- 10% R.H. and photophase of 14 hr, with nymphs of P. distinctus individualized in Petri dishes and fed as: T1-larvae of M. domestica during its whole nymphal phase: T2-larvae of M. domestica during its II instar and of T. molitor during the other instars: T3-larvae of M. domestica during II and III instars and of T. molitor during the other instars: T4-larvae of M. domestica during II, III and IV instars and of T. molitor during the V instar; T5- larvae of T. molitor during all instars. P. distinctus presents lower weight when fed with larvae of M. domestica. For this reason it is recommended to feed P. distinctus with T. molitor during its whole nymphal phase or with larvae of M. domestica only during II and III instars and T. molitor during IV and V instars.     

A comparison of mosquito predation by the fish Pseudomugil signifier Kner and Gambusia holbrooki (Girard) in laboratory trials.

Using larval Cx. annulirostris mosquitoes, this study compared the predation rate of Pseudomugil signifer and Gambusia holbrooki for four larval instars, three prey densities, and three vegetation densities. There was no significant difference in the quantity of first, second, and third instar larvae consumed by the two fish species after 24 h. There was a significant negative relationship between the predation rate and both larval instar and prey density for both fish species. In simulated vegetation trials, P. signifer performed marginally better than G. holbrooki in medium to high density vegetation (0.3 stems/cm 2 and 0.6 stems/cm2, respectively).     

两种蚜小蜂对烟粉虱寄主的产卵选择性(英文)

双斑恩蚜小蜂和桨角蚜小蜂是华南地区烟粉虱的两种优势种寄生蜂。本文研究了两种寄生蜂对不同龄期烟粉虱寄主的产卵选择特性。结果表明:两种寄生蜂均可寄生烟粉虱的1~4龄若虫。当只有1个龄期的烟粉虱若虫存在时,双斑恩蚜小蜂更多地寄生3龄和4龄若虫,较少寄生1龄和2龄若虫;而桨角蚜小蜂则更多地寄生3龄和2龄若虫,较少寄生1龄和4龄若虫。在4个龄期若虫同时存在时,双斑恩蚜小蜂会明显增加对3龄和4龄若虫的产卵寄生,降低对1龄和2龄若虫的寄生;而桨角蚜小蜂则增加对2龄和3龄若虫的寄生,减少对1龄和4龄若虫的寄生。寄主植物的差异不影响这二种蚜小蜂对各龄期烟粉虱若虫的产卵选择倾向。结果提示,烟粉虱若虫3龄和4龄是双斑恩蚜小蜂最适宜的寄主,而桨角蚜小蜂最适宜的寄主是烟粉虱2龄和3龄若虫。     

Developmental changes in the structure and function of mouthparts of phyllosoma larvae of the packhorse lobster, Jasus verreauxi (Decapoda: Palinuridae)

Mouthpart morphology and feeding behaviour of Jasus verreauxi phyllosomas (instars 1-13) were examined using scanning electron microscopy and video analysis, respectively, to better understand ingestion and processing mechanisms and to identify developmental changes in feeding biology. The density, robustness and complexity of mouthpart setation increased with development, oral field increased and there were a greater number of spinose projections on maxillae 1 in mid and late instar phyllosomas. The second and third maxillipeds were able to sweep a larger area due to their increased length, which effectively increased the size of the oral field. Changes in feeding behaviour were consistent with these morphological differences between instars. In late instars, the shredding and tearing efficiency of maxillae 1 increased, larger pieces of prey were pushed between the mandibles, and the mandibles were able to effectively grind food due to a slight rotation away from the transverse plane. Both morphological and behavioural observations suggests that the absolute size range of prey increases with phyllosoma body size and the prey processing (i.e. ability to capture, manipulate and grind prey) becomes more efficient with development. We suggest early instar phyllosoma are most suited to a diet comprising softer prey items, whereas later-instar phyllosoma are better equipped to deal with larger, fleshier prey.     

First report of Gyrodactylus spp. (Platyhelminthes: Monogenea) in the western Mediterranean Sea: molecular and morphological descriptions

The Gyrodactylus spp. fauna on species of gobies, Pomatoschistus, Gobiusculus, and Knipowitschia (Gobiidae: Teleostei), from the western Mediterranean and Adriatic seas is strikingly similar to that found in the Baltic Sea and eastern Atlantic Ocean, both in morphology and in internal transcribed spacer (ITS) rRNA. The fauna consisted of Gyrodactylus branchialis, G. ostendicus, G. gondae, G. rugiensis, G. rugiensoides, and G. arcuatus. No new species have been found. A morphometric comparison between G. branchialis from the Mediterranean and Adriatic seas and its type locality in Ostend (Belgium) showed significant differences in ventral bar and marginal hook features. The morphometric variation was lower in G. rugiensis, whereas no significant differences were found in G. ostendicus. Gyrodactylus branchialis and G. ostendicus collected on P. microps were slightly different in the ITS rDNA (-0.6%) compared with specimens on the closely related P. marmoratus, probably reflecting ongoing speciation. A hybrid zone was identified in the Vaccarès lagoon complex (France) where both host species are sympatric. There was no clear geographic or host-related pattern in the variation found in the ITS2 rDNA in G. arcuatus sampled from P. microps, G. flavescens, Pungitius pungitius, K. panizzae, and its original host Gasterosteus aculeatus (2 polymorphic sites). Of all studied species, only G. arcuatus, G. rugiensis, and G. rugiensoides showed minor intraspecific variation in the ITS rDNA. Hence, the physical separation by a shoreline of more than 10,000 km is hardly reflected in the parasite ITS rDNA.     

Morphological diversity of first instar larvae in Miltogramma subgenus Pediasiomyia (Diptera: Sarcophagidae, Miltogramminae)

The morphology of first instar larvae of three species of Miltogramma Meigen subgenus Pediasiomyia Rohdendorf is described using SEM and light microscope techniques. Miltogramma chrysochlamys (Rohdendorf), Miltogramma margiana (Rohdendorf) and Miltogramma przhevalskyi (Rohdendorf) share with other satellite flies the presence of an elongated sensillum basiconicum of the maxillary palpus and numerous longitudinal cuticular ridges on the integument of all segments; and they share with other Miltogramma spp. a maxillary palpus situated on a more or less raised base. While the first instar M. margiana is very similar to first instars of Miltogramma (sensu stricto), first instars of M. chrysochlamys and M. przhevalskyi share several features unique among Miltogramminae: antennal dome situated on a flat or indistinct basal ring, antennal dome flattened, border between pseudocephalon and first thoracic segment with a pair of fleshy processes, and basal ring with trichoid sensillum. First instars of M. chrysochlamys and M. przhevalskyi are unique in having both sb1 and sb2 of the sensilla basiconica of the maxillary palpus elongated, and M. przhevalskyi has an unpaired, median proleg on most abdominal segments.     

External morphology of the two cypridiform ascothoracid-larva instars of Dendrogaster: The evolutionary significance of the two-step metamorphosis and comparison of lattice organs between larvae and adult males (Crustacea, Thecostraca, Ascothoracida)

We describe the external morphology of the two cypridiform larval instars (first and second ascothoracid-larvae, or “a-cyprids”) of the ascothoracidan genus Dendrogaster. Ascothoracid-larvae of five species were studied with light and scanning electron microscopy, including both ascothoracid-larval instars in Dendrogaster orientalis Wagin. The first and second instars of the ascothoracid-larvae differ in almost all external features. The carapace of instar 1 has a smooth surface and lacks pores, setae, and lattice organs, while instar 2 has all these structures. The antennules of the first instar have only a rudimentary armament, the labrum does not encircle the maxillae, thoracopods 2-3 are not armed with a plumose coxal seta, and the abdomen is four-segmented (versus five-segmented in instar 2). Thus, the first ascothoracid-larva of Dendrogaster represents a transitional, generally brooded stage between the naupliar stages and the dispersive and fully functional second ascothoracid-larva that accomplishes settlement. The presence of two instars of ascothoracid-larvae (a-cyprids) in members of the order Dendrogastrida differs from the single cypridiform instar found in the Cirripedia (cyprid) and Facetotecta (y-cyprid), and we discuss the evolutionary significance of these ontogenies. We found lattice organs in both the second ascothoracid-larvae and in adult males of Dendrogaster. We could not observe both ascothoracid-larvae and males in any single species, but our data suggests that the lattice organs change significantly at the molt between these two instars. The lattice organs of second ascothoracid-larvae have no distinct keel and are situated in wide, shallow pits, whereas they have the ground pattern “crest-in-a-trough” morphology in adult males of two additional species examined for comparison. The positions of the terminal pores of lattice organs 1 and 2 also seem to change during maturation. These findings show that comparative data on lattice organ morphology for phylogenetic purposes must derive from strictly homologous instars, viz., the second ascothoracid-larva (a-cyprid) of the Ascothoracida, the y-cyprid of the Facetotecta, and the cyprid of Cirripedia. The ascothoracid-larvae of Dendrogaster and those of the family Ascothoracidae have four pairs of lattice organs, which suggests that this genus and family form a monophylum, to the exclusion of Ulophysema, which then brings into question the monophyly of the Dendrogastridae. Ulophysema is currently placed in the Dendrogastridae, but its second ascothoracid-larva has lattice organs of different and more plesiomorphic number and morphology. We briefly review lattice organ morphology across the Thecostraca. These organs are normally considered structures of the cypridiform larva and their presence in adult (males) Ascothoracida is unique in the Thecostraca. The continued morphological modification of these sensory structures in males compared to ascothoracid-larvae may suggest that they originated in adult thecostracans, but have come to be functional in the cypridiform larvae as well.     

单宁酸对淡色库蚊抗氰戊菊酯品系和敏感品系幼虫生长发育的影响

单宁酸是一种植物次生代谢物, 为探索其用于蚊幼虫防治的可能性,在室内测定了其对淡色库蚊Culex pipiens pallens抗氰戊菊酯品系和敏感品系1～4龄幼虫的毒性,并观察了其对存活幼虫生长发育的影响。结果表明,淡色库蚊敏感品系幼虫对单宁酸的敏感性比抗氰戊菊酯品系的要高,1～4龄幼虫分别高6.4、4.9、4.7和2.0倍。4个龄期幼虫中,无论是敏感品系还是抗氰戊菊酯品系,均是1龄幼虫对单宁酸的敏感性最高,3龄幼虫最低。在1 000 mg/L单宁酸持续作用下,敏感品系和抗氰戊菊酯品系各龄幼虫的存活率,均随处理时间延长而降低。与对照相比,饲养在100 mg/L～500 mg/L单宁酸溶液中的存活幼虫发育历期延长,敏感品系和抗氰戊菊酯品系发育历期分别延长了34.5～38.3 h和59.2～93.4 h。其中,125 mg/L浓度处理的敏感品系1～4龄幼虫,其发育历期与对照的差异达到了显著水平(P<0.05);抗性品系则在250 mg/L作用下也达到了差异显著水平(P<0.05)。但100～250 mg/L单宁酸处理淡色库蚊抗氰戊菊酯品系和敏感品系1龄幼虫,对其存活幼虫的化蛹率、羽化率和成虫性比均无显著影响。表明单宁酸对淡色库蚊幼虫的影响主要是延迟其生长发育,且影响程度与蚊虫对氰戊菊酯的敏感性有关。     

两种蚜小蜂对烟粉虱寄主的产卵选择性（英文）

双斑恩蚜小蜂和桨角蚜小蜂是华南地区烟粉虱的两种优势种寄生蜂。本文研究了两种寄生蜂对不同龄期烟粉虱寄主的产卵选择特性。结果表明: 两种寄生蜂均可寄生烟粉虱的1～4龄若虫。当只有1个龄期的烟粉虱若虫存在时,双斑恩蚜小蜂更多地寄生3龄和4龄若虫,较少寄生1龄和2龄若虫;而桨角蚜小蜂则更多地寄生3龄和2龄若虫,较少寄生1龄和4龄若虫。在4个龄期若虫同时存在时,双斑恩蚜小蜂会明显增加对3龄和4龄若虫的产卵寄生,降低对1龄和2龄若虫的寄生;而桨角蚜小蜂则增加对2龄和3龄若虫的寄生,减少对1龄和4龄若虫的寄生。寄主植物的差异不影响这二种蚜小蜂对各龄期烟粉虱若虫的产卵选择倾向。结果提示,烟粉虱若虫3龄和4龄是双斑恩蚜小蜂最适宜的寄主,而桨角蚜小蜂最适宜的寄主是烟粉虱2龄和3龄若虫。     

Effect of white grub developmental stage on susceptibility to entomopathogenic nematodes

The pathogenicity of the entomopathogenic nematodes Heterorhabditis bacteriophora Poinar and Steinernema scarabaei Stock & Koppenh?fer against different developmental stages of the Japanese beetle, Popillia japonica Newman, and the oriental beetle, Anomala (=Exomala) orientalis Waterhouse, were studied under laboratory conditions. The efficacy of S. scarabaei did not differ between second and third instars in P. japonica or A. orientalis or between small (young) and large (older) third instars in A. orientalis. However, H. bacteriophora efficacy decreased from first over second to third instar and also from small third instars to large third instars in A. orientalis but did not differ significantly between P. japonica larval stages. Once A. orientalis third instars had purged their intestines in preparation for pupation, no significant mortality by S. scarabaei and H. bacteriophora was observed. In contrast, P. japonica susceptibility to both nematode species gradually decreased from stage to stage from actively feeding third instars to pupae. In two additional experiments, we found no difference in Steinernema glaseri (Steiner) susceptibility between second and third instars of A. orientalis but an increase in S. scarabaei susceptibility from the second to third instar of Asiatic garden beetle, Maladera castanea (Arrow). Our observations combined with those of previous studies with other nematode and white grub species show that nematode efficacy against white grub developmental stages varies with white grub and nematodes species, and no generalization can be made.     

Interaction of a solitary larval endoparasitoid, Microplitis mediator, with its host, Mamestra brassicae: host acceptance and host suitability

Abstract:  Microplitis mediator (Haliday) (Hym., Braconidae) is an important parasitoid of early instar larvae of the European cabbage moth, Mamestra brassicae L. (Lep., Noctuidae). In the laboratory, we examined attack responses of female M. mediator to the first three larval instars of M. brassicae . Females were presented with M. brassicae larvae either one individual at a time in a no-choice experiment, or three individuals, one from each instar, simultaneously in a choice experiment. Whether or not there was choice, naïve female parasitoids attacked a high proportion of larvae and did not discriminate among instars. In the no-choice experiment, attacked larvae were reared, and parasitoid cocoons were produced from about 76% of larvae attacked as first and second instars, but from only 19% of larvae attacked as third instars. Dissections of attacked larvae from the choice experiment showed that about 79% of attacks on first and second instars resulted in oviposition compared with only 49% for third instars. When given choice, frequency and number of attacks on first instar larvae increased with increasing parasitoid experience. Our results suggest that first and second instar larvae of M. brassicae are suitable hosts for M. mediator , but that third instar larvae are suboptimal both because oviposition attempts were frequently unsuccessful and because immature parasitoids failed to complete development. Nevertheless, naïve attacking parasitoids exhibited minimal discrimination among instars, although experienced parasitoids most frequently attacked first instar larvae. The host selection behaviour of M. mediator is discussed in the context of optimal foraging theory and implications for biological control.     

Biology of Microplitis kewleyi (Hymenoptera: Braconidae): A parasite of Agrotis ipsilon (Lepidoptera: Noctuidae) larvae

Microplitis kewleyi Muesebeck is a gregarious internal parasite of larvae of the black cutworm Agrotis ipsilon (Hufnagel). Studies of the biology of the parasite revealed that there was an inverse relationship between host instar and parasite preference. Duration of development from egg to pupa ranged from 18 days at 27°C to 68.7 days at 16°C. Development from egg to pupa took 13.5–21.6 days when fourth and first instar host larvae, respectively, were parasitized. A larger number of parasites emerged from hosts parasitized in the fourth instar (22.4) than the first instar (11.5). Parasite pupation occurred when the host was in the fifth/sixth instar, depending on the instar parasitized. Thirty‐nine per cent of host larvae exposed as first instars to parasites died before parasite emergence. This decreased to 0% for host larvae exposed as fourth instars. The sex ratio was 1:1.2 (M:F). Thirty‐seven per cent of hosts exposed diurnally were stung, compared to 24% exposed nocturnally. Mean daily progeny was highest (12) on the first day, decreasing to zero after 20 days. Percent host parasitism was also highest on the first day (35%) decreasing to nearly 0% after 18 days. There appear to be three parasite larval instars. Host larvae often remained alive after parasite emergence.     

Water quality and the occurrence of Chironomus riparius Meigen (Diptera: Chironomidae) in a stream receiving sewage effluent

SUMMARY. The effects of a sewage effluent in Moat Brook, Staffordshire, were determined from regular collections of water and biological samples from directly comparable stations above and below the sewage outfall.
The eutrophic conditions below the outfall result in the replacement of Polypedilum laetum by Chironomus riparius (except in the spring) as the dominant member of the Chironominae. Continuous recruitment of first instar larvae to the population of C. riparius in summer and autumn results in much overlap of generations, but emergence trap captures suggest at least five generations in the year.
The usefulness of C. riparius as an indicator of enriched conditions in lotic ecosystems should be considered in relation to oviposition behaviour and the occurrence and seasonal variation in density of the adults and aquatic stages (including the more conspicuous third and fourth instar larvae).