Host preferences of introduced and native parasites (Hymenoptera: Braconidae) of phytophagous plant bugs (Hemiptera: Miridae) in alfalfa-grass fields in the northeastern USA

During an eight-year field study at two widely-separated locations (NJ & DE, USA), seven species of phytophagous mirid plant bugs were found in alfalfa and alfalfa-grass fields grown for animal forage. Five species of parasites were reared from these mirids. Two parasite species introduced from Europe killed significantly higher proportions of nymphs of the two important mirid pests of alfalfa than did native parasites. The introduced Peristenus digoneutis Loan parasitized an average of 31% of first and second generation tarnished plant bugs, Lygus lineolaris, a native insect; and the introduced Peristenus conradi parasitized 22% of first generation alfalfa plant bugs, Adelphocoris lineolatus, an introduced species. In addition, Peristenus pallipes significantly parasitized nymphs of Trigonotylus caelestialium (43%) and Leptopterna dolabrata (37%); both mirids are immigrant species. Because the parasite P. pallipes significantly attacked only these two non-native mirids, and is present in Europe, it also may be an accidental introduction to North America. A native wasp, Leiophron uniformis, heavily parasitized (49%) the native garden fleahopper, Halticus bractatus. A third native species, P. pseudopallipes, occasionally parasitized a few Lygus lineolaris in alfalfa at one location. Two other mirids, Stenotus binotatus and Megaloceroea recticornis, both accidently-introduced grass-feeding species, were not parasitized by native or introduced species. It is noteworthy that the effective host ranges of all the parasites in alfalfa-grass fields were limited: four of the five parasite species significantly parasitized only one of the seven mirid species, and the other parasite significantly parasitized only two mirids. Activity of the four common parasites was correlated with the mirids' host plant: three species principally parasitized alfalfa-feeding mirids, and one species principally parasitized grass-feeding mirids.     

Lethal and sub-lethal effects of acid, aluminium and lime on Gammarus pulex during repeated simulated episodes in a Welsh stream

SUMMARY. 1. A soft-water stream in upland mid-Wales was dosed with sulphuric acid, aluminium sulphate and limestone slurry to produce a zone of aluminium at low pH. and one of aluminium, low pH and added lime.
2. Three episodes of 24-h duration were induced, each separated by a 12-h inter-dosing period, and the responses of the crustacean Gammarus pulex monitored throughout.
3. G. pulex parasitized by the acanthocephalan Pomphorhynchus laevis were significantly more sensitive than unparasitized individuals.
4. Liming significantly reduced mortality during dosing but postexposure deaths were greatest for animals which had been exposed in the time zone.
5. The disruption of precopulalory behaviour in G. pulex was rapid and liming did not mitigate this response.     

The infection of nymphal Baetisbicaudatus by the mermithid nematode Gasteromermis sp.

1. This study reports the infection in nymphs of a bivoltine mayfly host ( Baetis bicaudatus ) in a high-elevation watershed by the mermithid nematode Gasteromermis sp. Infection by Gasteromermis causes mortality in two ways. Fifty per cent of the infections do not successfully develop beyond the initial stage of penetration and result in the early death of both host and parasite.
2. Infected hosts that survive this initial stage are rendered completely sterile by the infection (reproductively dead). In addition to complete sterility, the emergence size of parasitized nymphs is reduced and development time lengthened compared with unparasitized nymphs.
3. Parasite infection levels are stable from year to year at one site, but with a higher incidence of infection in the mayfly summer generation. Size differences between the generations at the time of infection may account for their different susceptibilities.
4. Within a year infection levels vary seasonally and spatially from 1 to 71%. Seasonally, there is a condensation of parasitized hosts towards the end of development as unparasitized nymphs emerge earlier. Spatially, infection levels show a downstream decline that may result from upstream dispersal by infected hosts or differential parasite survivorship at different elevations.     

Beetles, parasitoids and tropical morning glories: a study in host discrimination

Abstract. 1. The common cassidid beetle, Stolas sp., feeds as both larva and adult on the leaves of the vine, Ipomoea asarifolia , a wild relative of the sweet potato.
2. In the region around Manaus (Amazonas State, Brazil) an average of 86% of the egg clutches were completely parasitized by the eulophid, Emersonella niveipes.
3. The wasp is phoretic on female beetles. In comparison with field beetles that lacked phoretic wasps, beetles associated with wasps produced eggs sooner, laid more egg clutches, and had a shorter laboratory life expectancy.
4. Host discrimination by the wasp is probably an active process rather than a passive association with randomly encountered beetles.
5. Emersonella niveipes also attacks Chelymorpha cassidea , a pest of sweet potato. Adults of Stolas sp. do not feed on sweet potato foliage nor occur in sweet potato fields, so they could provide a useful innocuous alternate host for Emersonella niveipes.
6. As some species in the Convovulaceae are important weeds in field crops, foliage-feeding cassidid beetles may play a useful role in weed suppression. Any biological control programme for the suppression of sweet potato pests may favour the spread of those noxious weeds that share the herbivore fauna of sweet potatoes.     

Limitation of superparasitism by Aphidius rhopalosiphi: a consequence of aphid defensive behaviour

Abstract. 1. The behavioural mechanisms limiting superparasitism by Aphidius rhopalosiphi (DeStefani-Perez) are described.
2. A.rhopalosiphi did not discriminate between parasitized and unparasitized aphids, or avoid attacking and ovipositing in previously parasitized aphids.
3. Aphid defensive behaviour was increased for a short period after a parasite stabbing attack. In response to this behaviour the number of parasite stabbing attacks subsequently undertaken declined.
4. Once a stabbing attack had been initiated, parasite oviposition success was unaffected by aphid defensive behaviour.
5. It is concluded that applied defensive behaviour, by limiting the number of stabbing attacks undertaken by A.rhopalusiphi , effectively limits the number of parasite eggs laid and the extent to which super parasitism occurs.     

Competition, resource partitioning and coexistence of an endoparasitoid Encarsia perniciosi and an ectoparasitoid Aphytis melinus of the California red scale

Abstract. 1. Laboratory experiments and field studies were conducted to explain the coexistence of an endoparasitoid, Encarsia perniciosi Tower, and an ectoparasitoid, Aphytis melinus DeBach, both of which were introduced into California to control the California red scale, Aonidiella aurantii (Mask.).
2. Encarsia parasitized all scale stages but it preferred first and second instar scales. This is in contrast to Aphytis melinus , in which previous studies have shown that it parasitizes second and third instar females and second instar males but prefers third instar female scales. Encarsia developed most rapidly when it parasitized an early second instar and slowest when it parasitized the mature female scale. However, on early second instar scales it was about 80% as fecund as a wasp that emerged from a mature female scale.
3. Second instar scales parasitized by Encarsia were accepted by Aphytis as readily as unparasitized scales.
4. Encarsia did not distinguish between unparasitized hosts and those previously parasitized by Aphytis.
5. Encarsia always outcompeted by Aphytis when both species parasitize the same host.
6. Encarsia prefers scale on stems whereas Aphytis prefers those on leaves and fruits. This, too, may be a result of interspecific competition with Aphytis.
7. The partitioning of the scale resource by the two species explains why they coexist in coastal southern California but it does not explain why Encarsia disappeared from citrus groves in the inland valleys coincident with the introduction of Aphytis melinus into southern California.     

Malarial Parasites of the "Jesu Cristo" Lizard Basiliscus basiliscus (Iguanidae) in Panama

SYNOPSIS. The iguanid lizard Basiliscus basiliscus in Panama is parasitized by Plasmodium basilisci and P. achiotense sp. nov. P. basilisci in this host is characterized by schizonts containing 4–14 merozoites, with schizonts parasitizing proerythrocytes containing more merozoites than those in erythrocytes. Asexual parasites lack cytoplasmic projections, while mature gametocytes are round or oval with regular margins.
P. achiotense is characterized by the combination of prominently pigmented, large schizonts containing 36–56 merozoites and oval or round gametocytes which are about 1/3 larger than those of P. basilisci.
EE-schizonts of P. basilisci were observed commonly in thrombocytes and occasionally in lymphocytes, and appeared early in experimental infections induced by blood inoculation.     

Factors influencing aggregation between nymphs of the lime aphid, Eucallipterus tiliae (L.)

Abstract. 1. Aggregation in the lime aphid is influenced by the newly-born nymphs staying close to their mother.
2. The aggregations are brought about by gregariousness between the first instar nymphs and their reluctance to move far from their birthplace.
3. As the nymphs mature they become more wide-ranging and leave the aggregation. Dispersal is also promoted by a lack of gregariousness between different instars.
4. Such aggregations remain intact only as long as the adult continues to reproduce the relatively sedentary first instars.
5. The significance of this behaviour in the spacing of the lime aphid is discussed.     

Chondrichthyans from the Lower Carboniferous of Yakutia,Russia

Paleontological Journal - Teeth of Cladodoides cf. wildungensis (Jaekel), fin spines of Ctenacanthus cf. angulatus Newberry et Worthen and Ctenacanthus sp. occur in the Lower Carboniferous Emyaksin...     

The effect of the acanthocephalan parasite (Pomphorhynchus laevis) on the drift of its intermediate host (Gammarus pulex)

SUMMARY 1. The drift of Gammarus pulex in a population in which approximately 20% of adults are infected with the acanthocephalan parasite Pomphorhynchus laevis was monitored at margin and mid-river sites in the River Teme, England over a 24-h period in mid-summer.
2. Drift densities showed a diurnal pattern with a large increase at night, independent of parasite burden.
3. There was no significant effect of site (margin or mid-river) on the proportion of parasitized and unparasitized G. pulex found in the drift or the benthos.
4. The drift of parasitized G. pulex was significantly greater than unparasitized animals. Gammarids harbouring only one parasite were found in significantly higher proportions in the drift than those with two or more parasites.
5. At both sites (margin and mid-river) the proportion of unparasitized adult G. pulex in the drift was significantly lower than that in the benthos. However, there was a significantly higher proportion of parasitized animals in the drift than in the benthos.     

Lime treatment and its effects on the chemistry and biota of hardwater eutrophic lakes

1. The main focus of this study was to investigate the effects of single and multiple moderate doses of lime (slaked lime, Ca(OH)₂, and/or calcite, CaCO₃) on eutrophic hardwater lakes. This information would contribute to strategies to manage phytoplankton and macrophyte biomass in eutrophic lakes.
2. Water chemistry and biota were monitored for up to 7 years after initial lime treatment and results were compared with reference systems.
3. Complementary studies investigated the effect of lime on macrophytes in ponds, irrigation canals and microcosm experiments.
4. When water pH was kept within its natural range (≤ 10), single and multiple lime applications to lakes and ponds controlled macrophyte biomass, without negatively affecting invertebrate communities.
5. Single lime treatments at moderate dosages of lakes and ponds resulted in variable and mostly temporary changes in chlorophyll a (chl a ) and phosphorus (P) concentration. Although sediment P release was reduced in single-dose lakes during the first winter following treatment, reductions appeared temporary.
6. Multiple treatments of lakes and ponds were effective at reducing both chl a and P concentrations over longer periods. Mean winter P release rate was also reduced after initial treatment.
7. In laboratory studies, sediment cores were incubated with eight different treatments to assess P release. Redox-sensitive treatments were no more effective at lowering total P concentration in overlying water than some redox-insensitive treatments. Lime reduced total P concentrations, but was not as effective as treatments with alum.
8. The use of lime in managing macrophyte and phytoplankton biomass in shallow, hardwater lakes and ponds may be preferable over other treatments, because lime is economical and non-toxic as long as pH is kept within a natural range.     

Mayfly locomotory responses to endoparasitic infection and predator presence: the effects on predator encounter rate

SUMMARY. 1. The effects of predaceous stoneflies and endoparasilism by mermithid nematodes on the locomotory behaviour of individual mayflies were studied in the laboratory. The effects of predator- and parasite-induced changes in activity on predator encounter, attack and capture rates were also examined.
2. In response to predator presence non-parasitized mayflies decreased activity, while parasitized mayflies increased activity, in comparison to a control group. As a result, the faster-moving parasitized individuals encountered stonefly predators much more frequently. The frequency of attacks per encounter did not change.
3. In view of this and other studies, two predator-avoidance strategies based on mayfly locomotory and defensive capabilities are proposed: (a) Mayflies that are able effectively to flee a predator's attack and those able to employ a behavioural defence may decrease their mean velocity when a predator is detected, thereby reducing the likelihood of an encounter while allowing foraging to continue; (b) Slower-moving or otherwise defenceless mayflies may immediately move away from the area in which a predator is perceived in order to avoid an encounter.
4. In the absence of a predator, parasitized mayflies demonstrated greatly increased activity. This probably reflects increased foraging in response to the nutritional deficit imposed by the endoparasite. A decrease in upstream movement by parasitized mayflies may also indicate a parasite-imposed energy stress.     

Evidence of mycoparasitism and hypermycoparasitism in Early Cretaceous amber

Evidence of mycoparasitism and hypermycoparasitism is demonstrated in Early Cretaceous Burmese amber. The agaric, Palaeoagaracites antiquus gen. sp. nov., is parasitized by the mycoparasite, Mycetophagites atrebora gen. sp. nov., which in turn is parasitized by the hyperparasite, Entropezites patricii gen. sp. nov. This discovery shows that sophisticated patterns of fungal parasitism were well developed some 100 Myrago.     

The window of vulnerability and its effect on relative parasitoid abundance

Summary. 1. The length of time that a gall-forming midge, Rhopalomyia califomica , was vulnerable to attack by four parasitoid species was measured in the field at two locations.
2. The midge had a restricted window of vulnerability to each of the parasitoid species, but similar windows of vulnerability were found at the two sites.
3. A stage-structured model was used to illustrate that the length of the vulnerable window should have no effect on the fraction parasitized by a single parasitoid species if that species is the only parasitoid attacking the host in a coupled host-parasitoid interaction. However, the length of the window of vulnerability can have a positive effect on the fraction parasitized by a species in competition with other parasitoid species.
4. The length of the window of vulnerability can help explain the relative field abundance of four of the common parasitoid species of R.californica.     

Saurian Malarial Parasites in Eastern Panama

SYNOPSIS Plasmodium gonatodi sp. nov. is described from Gonatodes albogularis fuscus of eastern Panama. It is characterized by elongate gametocytes and polymorphic schizonts containing 12-46 nuclei when apparently mature. Both proerythrocytes and erythrocytes are commonly parasitized, host cells are hypertrophied and distorted, and their nuclei are displaced. Prematuration sexual stages may be irregularly shaped and larger than mature gametocytes.
Plasmodium diploglossi Aragão and Neiva , 1909 is reported from Mabuya mabouya in eastern Panama, and Plasmodium morulum sp. nov. is described from this host. P. morulum usually parasitizes immature erythrocytes, and is characterized by lenticular or oval to round gametocytes, and schizonts with 14-40 nuclei usually arranged in a globular mass. Host cells are slightly hypertrophied and distorted, and their nuclei are usually displaced. Inoculation of infected blood into clean hosts produces numerous schizonts in white cells as well as in the erythrocyte series.
Pigment in both P. gonatodi and P. morulum , if present, consists of a few minute dark dots which do not meet the polarized light test for hemozoin.     

青海湖裸鲤体腔寄生蠕虫群落研究

青海湖裸鲤体腔为三种寄生蠕虫寄生,即裂头绦虫裂头蚴,舌状绦虫裂头蚴和对盲囊缄虫的三期幼虫,这几种蠕虫不同大小的青海湖裸鲤中数量差异很大,将其看作一个组分群落,并根据其发生数量进行模糊聚类和极点排序,结果将其分为二个亚组分群落,即体长小于１５０ｍｍ的青海湖裸鲤体腔蠕虫亚组分群落和体长大于１５０ｍｍ的个体的体腔蠕虫亚组分群落。这与宿主的行为和食性改变有密切关系,舌状绦虫与另两种蠕虫间有显著负协调关系。     

山东莱芜地区晚寒武世炒米店组牙形石生物地层学研究

本文报道了山东莱芜地区黄羊山剖面炒米店组的牙形石生物地层学研究成果。在该剖面上寒武统的炒米店组建立了9个牙形石带,自上而下分别是Cordylodusangulatus带,C.lindstromi带,C.intermedius带,C.proavus带,Eoconodontusnotchpeakensis带,Proconodontusmuelleri带,P.posterocostatus带,P.tenuiserratus带和Prooneotodusrotundatus-Muelleroduserectus带。牙形石动物群的面貌显示该地区炒米店组顶部在时代上已属早奥陶世,表明该地区的寒武-奥陶界线与三山子组白云岩的底界并不一致,后者在层位上稍高。建立并描述了一副牙形石新种Westergaardodinahuangyangshanensissp.nov.。     

中国全肿腿蜂属种类记述(膜翅目,肿腿蜂科)

系统研究了我国全肿腿蜂属HolepyrisKieffer,190 4的种类 ,记录 7新种中国 2新纪录种和 1已知种共 10种 ,包括采自山东、浙江、福建、台湾和贵州的热海全肿腿蜂H .atamiensis (Ashmead) ,采自河南的瘦全肿腿蜂H .macilentussp .nov .,采自福建的角唇全肿腿蜂H .angulatussp .nov .,采自山东的黄足全肿腿蜂H .fulvussp .nov .,采自浙江和甘肃的褐足全肿腿蜂H .fuscussp .nov .,采自浙江和福建的惹全肿腿蜂H .yambaruTerayama ,采自浙江的古田山全肿腿蜂H .gutianshanensissp .nov .,采自浙江和福建的中华全肿腿蜂H .sinensissp .nov .,采自山东的细胸全肿腿蜂H .susanowoTerayama和采自浙江的伊文思全肿腿蜂H .evansisp .nov .。全部模式标本保存于浙江大学植物保护系寄生蜂标本室。热海全肿腿蜂Holepyrisatamiensis (Ashmead ,190 4)(图 1～ 2 )分布 :中国 (山东 ,浙江 ,福建 ,台湾 ,贵州 ) ;日本。瘦全肿腿蜂 ,新种Holepyrismacilentussp .nov .(图 3～ 4,9)分布 :中国 (河南 )。鉴定标本 :正模♀ ,1998 0 7 14,河南内乡宝天曼 ,陈学新采 ,编号 98873 1。角唇全肿腿蜂 ,新种Holepyrisangulatussp .nov.(图 5～ 6)分布 :中国 (福建 )。鉴定标本 :正模♂ ,1994 0 7 14,福建武夷山桐木 ,陈学新采 ,编号 94     

Interference by the mantispid Mantispa uhleri with the development of the spider Lycosa rabida

Abstract. 1. The larvae of Mantispa uhleri Banks (Neuroptera: Mantispidae) board spiders to await the production of an egg sac containing their obligate developmental food. While aboard the spider, larvae maintain themselves by feeding on spider blood. This parasitic behaviour was investigated by allowing larvae to board sixth instar Lycosa rabida Walckenaer (Araneae: Lycosidae). Larval parasitism has a direct and indirect effect on the developmental physiology of the spider.
2. The direct effect, equal in both spider sexes, is an increase in development time and a decrease in adult size.
3. The indirect effect on development time and adult size is brought about by the loss of an instar in female spiders only. Parasitized females were mature at nine or ten instars; control females at ten or eleven. Male instar number was not affected; both control and parasitized males were mature at nine or ten instars.
4. The net result is that parasitized female spiders are even smaller than would be predicted from the direct effect alone, but actually mature faster than control females. In males there is only the direct effect. The adaptive significance of this sexually dimorphic response is discussed.     

Nature and bioactivities of endolichenic fungi in Pseudocyphellaria sp., Parmotrema sp. and Usnea sp. at Hakgala montane forest in Sri Lanka

Aim:  The aim of this study was to investigate the nature and bioactivities of endolichenic fungi in three abundant lichens, Pseudocyphellaria sp., Usnea sp. and Parmotrema sp. in the lower elevation of Hakgala montane forest in Sri Lanka.
Methods and Results:  Endolichenic fungal strains, fungi that live asymptomatically in the lichen thallus, much the same way as endophytic fungi live within healthy plant tissues, were isolated from three abundant lichen species, Pseudocyphellaria sp., Usnea sp. and Parmotrema sp., at Hakgala montane forest in Sri Lanka, using the surface sterilization method. Nine endolichenic fungal strains were isolated from Parmotrema sp. and Usnea sp. separately, while 11 endolichenic fungi were recovered from the lichen Pseudocyphellaria sp. Isolation of endolichenic fungus Chrysosporium sp. 2 was common to all three lichen species. Substrate utilization patterns and antifungal activities of eight endolichenic fungal species were evaluated and the results revealed that all the test fungi were able to produce at least one enzyme to utilize the test substrates. Nigrospora sp., Chrysosporium sp. 1 and 2 and Cladosporium sp. showed antifungal activities on growth of some selected plant pathogenic fungi.
Conclusions:  Endolichenic fungal strains (29) were isolated from the lichens Parmotrema sp., Usnea sp. and Pseudocyphellaria sp. in Sri Lanka. Chrysosporium sp. 2 was common in all three lichens. Some of these endolichenic fungal strains showed antifungal activities against common plant pathogenic fungi and they are capable of utilizing the substrates by producing specific enzymes.
Significance and Impact of the Study:  The diversity and prevalence of the endolichenic fungi have not been studied extensively and this is the first report of isolation and identification of endolichenic fungi in lichens available in Sri Lanka.