Aphis fabae and Myzus persicae (Hemiptera: Aphididae) are insect pests that damage sugar beet and bean crops. Both are responsible for losses in yield and transmission of viral diseases, and may be present on the same host at the same time. Three parasitoid species, Aphidius colemani, Lysiphlebus testaceipes and Lysiphlebus fabarum (Hymenoptera: Braconidae: Aphidiinae) have the potential to be used as biological control agents against at least one of these species of aphids. As a first step prior to the implementation of a biological control program, our aim was to understand the host selection behaviour of the parasitoids, particularly when both aphids are present. We recorded the host acceptance (number of insertions of the ovipositor / number of antennal contacts), suitability (number of mummies / the number of insertions of the ovipositor) and emergence (number of adults emerging from mummies) of these three aphid parasitoids when parasitizing the two aphids. We also analyzed the effect of the host plant on the host preference of the parasitoid. Females of each parasitoid species (n = 15) were exposed to 20 aphids of A. fabae or M. persicae, or a mixture of these two species of aphids, for 15 min, on a leaf disc of each of the two host plants, sugar beet and bean. Higher host acceptance and suitability were recorded for A. colemani attacking both species of aphid: A. fabae (43 and 46%) and M. persicae (43 and 46%) on beet and bean plants respectively, compared to L. testaceipes and L. fabarum. L. testaceipes and L. fabarum showed a clear preference for A. fabae. L. fabarum accepted M. persicae on both plants only when it was mixed with A. fabae, probably due to a confusion effect. We found that the host plant played a significant role in host acceptance, host suitability. We conclude that A. colemani is the better of the three parasitoids studied for the biological control in bean, and particularly, sugar beet crops. and Loulou Albittar, Mohannad Ismail, Claude Bragard, Thierry Hance.
Myxobolus filamentum sp. n. was found infecting gill filaments of three of 39 Brycon orthotaenia Günther specimens examined (8%), which were taken from the river São Francisco in Minas Gerais state, Brazil. Plasmodia of the parasite were white and long, measuring 5 mm in lenght. Mature spores of M. filamentum sp. n. were oval from the frontal view and biconvex from the lateral view, measuring 7.5-9.7 µm (9.0 ± 0.3 µm) in length and 5.2-7.3 µm (6.2 ± 0.4 µm) in width. The polar capsules were elongated and equal in size, measuring 3.8-5.5 µm (4.7 ± 0.3 µm) in length and 1.3-2.2 µm (1.7 ± 0.1 µm) in width. The development of the parasite led to compression of the adjacent tissues and inflammatory infiltrate with granulocytic cells. Ultrastructural observation revealed that the plasmodia were delimited by two membranes, which had numerous and extensive pinocytotic channels extending into the wide ectoplasm zone. The plasmodial wall exhibited abundant villi-like projections and a thin layer of granular material prevented direct contact between the plasmodial wall and the host tissue. Phylogenetic analysis, based on 18S rDNA, showed M. filamentum sp. n. as a sister species of Myxobolus oliveirai Milanin, Eiras, Arana, Maia, Alves, Silva, Carriero, Ceccarelli et Adriano, 2010, a parasite of other fish species of the genus Brycon Müller et Troschel from South America., Juliana Naldoni, Suellen A. Zatti, Kassia R.H. Capodifoglio, Tiago Milanin, Antônio A.M. Maia, Marcia R.M. Silva, Edson A. Adriano., and Obsahuje bibliografii
Quantitative community-wide moth surveys frequently employ flight-interception traps equipped with UV-light emitting sources as attractants. It has long been known that moth species differ in their responsiveness to light traps. We studied how the settling behaviour of moths at a light trap may further contribute to sampling bias. We observed the behaviour of 1426 moths at a light tower. Moths were classified as either, settling and remaining still after arrival, or continually moving on the gauze for extended periods of time. Moths that did not move after settling may not end up in the sampling container of the light trap and therefore are under-represented in automated trap samples relative to their true proportions in the community. Our analyses revealed highly significant behavioural differences between moths that differed in body size. Small moths were more likely to remain stationary after settling. As a corollary, representatives of three taxa, which in Europe are predominantly small species (Nolidae, Geometridae: Eupitheciini, Erebidae: Lithosiini), usually settled down immediately, whereas most other moths remained active on or flying around the trap for some time. Moth behaviour was also modulated by ambient temperature. At high temperatures, they were less likely to settle down immediately, but this behavioural difference was most strongly apparent among medium-sized moths. These results indicate the likely extent of the sampling bias when analysing and interpreting automated light-trap samples. Furthermore, to control for temperature modulated sampling bias temperature should always be recorded when sampling moths using flight-interception traps. and Mirko Wölfling, Mira C. Becker, Britta Uhl, Anja Traub, Konrad Fiedler.
Copepods of the genus Achtheinus Wilson, 1908 (Pandaridae) are parasites of elasmobranchs that attach to their fins, gill slits and around the nostrils. Specimens of Achtheinus pinguis Wilson, 1912 were collected and examined using histology and scanning electron microscopy to determine their way of attachment to the host and the possible effect on the host. They insert their antennae deep into the dermis of the shark's skin, which causes the most damage due to possible tissue compression and/or fibrosis as well as rupture of the connective tissue. Additionally, the presence of the copepod on the skin causes cell erosion of the epidermal cells and thus reduces the number of epidermal layers. The maxillipeds are used to attach to the placoid scales that cover the shark's skin and probably serve to keep the copepod and inserted antennae in position. This is accomplished by the insertion of the placoid scales into the flaccid corpus of the maxillipeds. Observed damage seems to be negligible to the shark apart from the possibility of secondary infection., Susan M. Dippenaar, Anine Jordaan., and Obsahuje bibliografii
The whipworms, i.e. parasitic nematodes of the genus Trichuris Roederer, 1761, infect a variety of mammals. Apparently low diversity of primate-infecting species of Trichuris strongly contrasts with the high number of species described in other mammalian hosts. The present study addresses the diversity of whipworms in captive and free-ranging primates and humans by analysing nuclear (18S rRNA, ITS2) and mitochondrial (cox1) DNA. Phylogenetic analyses revealed that primate whipworms form two independent lineages: (i) the Trichuris trichiura (Linnaeus, 1771) clade comprised of genetically almost identical whipworms from human and other primates, which suggests the ability of T. trichiura to infect a broader range of primates; (ii) a clade containing primarily Trichuris suis Schrank, 1788, where isolates from human and various primates formed a sister group to isolates from pigs; the former isolates thus may represent of more species of Trichuris in primates including humans. The analysis of cox1 has shown the polyphyly of the genera Trichuris and Capillaria, Zeder, 1800. High sequence similarity of the T. trichiura isolates from humans and other primates suggests their zoonotic potential, although the extent of transmission between human and other non-human primates remains questionable and requires further study., Jana Doležalová, Miroslav Oborník, Eva Hajdušková, Milan Jirků, Klára J. Petrželková, Petra Bolechová, Cristina Cutillas, Rocio Callejón, Jozef Jaroš, Zuzana Beránková, David Modrý., and Obsahuje bibliografii
The sex determination cascades in insects are diversified at the top of the cascade, where different primary molecular signals are employed, while at the bottom of the cascades, particularly the doublesex genes, are highly conserved. Here, we identified the doublesex ortholog (Btau-dsx) of Bactrocera tau, a pumpkin fruit fly, and found that Btau-dsx is composed of six exons and five introns with an additional short "m" exon located in the second intron. Btau-dsx is different from its orthologs in most dipteran insects: Its pre-mRNA is sex-specifically spliced to yield three (two male and one female) instead of two transcript variants. The two deduced proteins produced by the male-specific transcripts are a functional (Btau-DSXM1) and a truncated (Btau-DSXM2) protein, while the female-specific transcript produces the functional Btau-DSXF protein. These three proteins contain all conserved domains except Btau-DSXM2 which has no OD2 domain. The female-specific transcript is detected in both fertilized and unfertilized eggs and in both somatic and germ cells of the adult females, while the male-specific transcript is detected only in fertilized eggs and in the abdominal tissues and testes of adult males. The presence of the Btau-dsxM1 transcript in fertilized eggs at the early syncytium stage suggests that in XY embryos, the Y-linked M factor gene may function quite soon after fertilization to alter the splicing pattern of Btau-dsx pre-mRNA from the female-specific to the male-specific mode. Injection of Btau-dsxF dsRNA into recently emerging females can reduce the expression of vitellogenin (Btau-Vg) and causes some defects in the ovaries, indicating that Btau-dsxF works upstream of Btau-Vg., Thanaset Thongsaiklaing, Hataichanok Passara, Mingkwan Nipitwathanaphon, Lertluk Ngersiri., and Obsahuje bibliografii
Macrocentrus cingulum is an important polyembryonic endoparasitic wasp that attacks larvae of the Asian corn borer, Ostrinia furnacalis (Guenée) and the European corn borer, O. nubilalis (Hübner). Parasitoids use antennae as the main sensory organ to recognize herbivore-induced plant volatiles as host searching cues. The antennal olfaction proteins, odorant receptors (ORs) and ionotropic receptors (IRs) are involved in olfactory signal transduction pathway as a sensory neuron response. In the present study, we constructed a cDNA library from the male and female antennae for identifying the olfaction-related genes in M. cingulum. For that, we sequenced 3160 unique gene sequences and annotated them with gene ontology (GO), cluster of orthologous groups of proteins (COG), and KEGG ontology (KO). Through the homology search, we identified 9 odorant receptors (ORs), 3 ionotropic receptors (IRs) and 1 odorant binding protein (OBP) genes from the cDNA library sequences. Additionally, the expression patterns of these ORs and IRs in different tissues (antennae, heads, thoraxes, abdomens, and legs) were demonstrated by RT-PCR. The qualitative gene expression analyses showed that most of the OR genes were more highly expressed in female than male antennae; whereas IRs, unlike ORs, were more expressed in various male than females tissues. We are the first to report ORs and IRs in M. cingulum, which should help in deciphering the molecular basis of olfaction system in this wasp., Tofael Ahmed, Tian-Tao Zhang, Zhen-Ying Wang, Kang-Lai He, Shu-Xiong Bai., and Obsahuje bibliografii
Tapinoma melanocephalum is a worldwide distributed, highly invasive ant species. It lives in close association with human societies and its distribution is human-mediated in large measure. The geographical origin of this ant species is unknown, but its introduction in areas previously devoided of its presence can represent a threat to the native biota, act as an agricultural pest or as a pathogen vector. To investigate the genetic structure and phylogeography of this species we identified 12 new polymorphic microsatellite markers, and in addition, we tested and selected 12 ant-universal microsatellites polymorphic in T. melanocephalum. We genotyped 30 individuals from several islands of Micronesia and Papua-New Guinea. All 24 loci exhibited strong homozygosity excess (45-100%, mean = 86%), while the number of alleles per locus reached usual values (2-18, mean = 6.5), resulting in levels of expected heterozygosity much higher than observed. Based on several robust tests, we were able to exclude artefacts such as null alleles and allelic dropout as a possible cause of the observed pattern. Homozygosity excess might be a consequence of founder effect, bottleneck and/or inbreeding. As our sample population was composed of individuals from several distinct localities, the Wahlund effect might have contributed to the increased homozygosity as well. Despite the provisionally observed deviation from the Hardy-Weinberg equilibrium, the newly developed microsatellites will provide an effective tool for future genetic investigations of population structure as well as for the phylogeographic study of T. melanocephalum., Jan Zima Jr., Ophélie Lebrasseur, Michaela Borovanská, Milan Janda., and Obsahuje bibliografii
Animals, including human beings, tend to respond more strongly to stimuli that are associated with the highest relative rewards. This applies not only to food rewards but also to reproductive success. In the present review article this issue is discussed for insects in connection with intersexual communication and flower-visiting behaviour. Implications of the preference for supernormal visual releasing stimuli are examined from a sensory and evolutionary perspective, including a consideration of the choice of potential mates and recognition of the most rewarding flowers., Karl Kral., and Obsahuje bibliografii
Parasitic organisms inhabiting the alimentary canal should permanently resist the destructive action of host digestive enzymes. The intestinal parasites were shown to produce specific protease inhibitors protecting them from proteolysis. However, little is known about this adaptive mechanism in cestodes so far, especially for the tapeworms dwelling inside the fish intestines. Here, we explored the ability to inactivate proteolytic enzymes in the fish tapeworm Eubothrium rugosum (Batsch, 1786) (Bothriocephalidea) parasitising the intestine of wild burbot, Lota lota (Linnaeus). The assays were conducted with different concentrations of commercial trypsin and homogenate of intestinal mucosa both being the sources of proteinases. The incubation of live E. rugosum in trypsin solutions of two different concentrations caused a significant decrease in the enzyme activity. The extent of activity reduction was dependent on trypsin concentration. At the same time, the inhibitory effect of the worm incubation medium turned out to be statistically insignificant. These findings suggest partial adsorption of the enzyme to the tegument surface, with its further inactivation. In contrast to the incubation medium, the worm extract suppressed over 80% of trypsin activity and nearly half of the proteolytic activity in the mucosa homogenate. Notably, the inhibitory activity of the tapeworms hardly depended on their size characteristics. Finally, the research has demonstrated secretion of proteinase inhibitor in E. rugosum, which appears to be essential for its survival in enzymatically hostile environment., Galina I. Izvekova, Tatyana V. Frolova, Evgeny I. Izvekov., and Obsahuje bibliografii