Search results for "class"
showing 10 items of 38174 documents
Effects of two acanthocephalan parasites on the fecundity and pairing status of female Gammarus pulex (Crustacea: Amphipoda)
2002
Acanthocephalan parasites are known to alter the reproductive biology and physiology of their hosts in various ways. In this study we investigated the influence of two acanthocephalan parasites, Pomphorhynchus laevis and Polymorphus minutus, on the fecundity and pairing success of female Gammarus pulex. The results show that P. laevis and P. minutus affect female intermediate host reproduction in different ways. Females infected with P. minutus were totally castrated, whereas those infected with P. laevis only showed reduced fecundity. The oocytes of P. laevis-infected females showed a similar structure to those of uninfected females, although infected females had a higher proportion of ooc…
Identification and characterization of five polymorphic microsatellite loci in the freshwater copepod Hemidiaptomus gurneyi (Copepoda: Calanoida: Dia…
2016
Hemidiaptomus diaptomid copepods are known to be excellent biological indicators for the highly biodiverse crustacean communities inhabiting Mediterranean temporary ponds (MTPs), an endangered inland water habitat whose conservation is considered a priority according to the “Habitat Directive” of the European Union. This study reports on the characterization of five polymorphic microsatellite loci in Hemidiaptomus gurneyi, to be used as markers for fine-scale studies on the population genetic structure and metapopulation dynamics of a typical and obligate MTP dweller. The five selected loci proved to be polymorphic in the species, with three to five polymorphic loci per studied population. …
Are mussels able to distinguish underwater sounds? Assessment of the reactions of Mytilus galloprovincialis after exposure to lab-generated acoustic …
2016
This study examined the effects of lab-generated acoustic signals on the behaviour and biochemistry of Mediterranean mussels (Mytilus galloprovincialis). The experiment was carried out in a tank equipped with a video-recording system using six groups of five mussels exposed to five acoustic treatments (each treatment was replicated three times) for 30 min. The acoustic signals, with a maximum sound pressure level of 150 dB rms re 1 μPa, differed in frequency range as follows: low (0.1–5 kHz), mid-low (5–10 kHz), mid (10–20 kHz), mid-high (20–40 kHz) and high (40–60 kHz). The exposure to sweeps did not produce any significant changes in the mussels' behaviour. Conversely, the specimens expos…
Species composition and richness of aphid parasitoid wasps in cotton fields in northern China
2017
AbstractThe cotton aphid, Aphis gossypii (Hemiptera: Aphididae), is a serious pest of cotton across the globe, particularly in the cotton agroecosystems of northern China. Parasitic wasps are deemed to be important natural enemies of A. gossypii, but limited information exists about their species composition, richness and seasonal dynamics in northern China. In this study, we combine sampling over a broad geographical area with intensive field trials over the course of three cropping seasons to describe parasitoid-hyperparasitoid communities in cotton crops. We delineate a speciose complex of primary parasitoids and hyperparasitoids associated with A. gossypii. Over 90% of the primary paras…
Chemical composition, herbicidal and antifungal activity of Satureja cuneifolia essential oils from Spain
2016
The chemical composition of essential oils from Satureja cuneifolia growing in east Spain was analyzed by GC, GC/MS. Forty-five compounds accounting for 99.1% of the total oil were identified. Camphor (47.6%), followed by camphene (13.6%) were the main compounds. Their herbicidal and antifungal activity was tested in vitro against three weeds (Amaranthus hybridus, Portulaca oleracea and Conyza canadensis) and eleven common pathogenic or saprophytic fungi (Phytophthora citrophthora, P. palmivora, Pythium litorale, Verticillium dahlia, Rhizoctonia solani, Penicillium hirsutum, Colletotrichum gloeosporioides, Phaeoacremonium aleophilum, Phaemoniella chlamydospora, Cylindrocarpon liriodendri a…
Neighbouring plants and perception of predation risk modulate winter browsing by white-tailed deer (Odocoileus virginianus)
2018
The presence of neighbouring plants and predation risk can affect trophic interactions between plants and herbivores. We hypothesized that the relative preference for neighbouring species would determine winter herbivory and that predation risk would modulate browsing pressure. We tested these hypotheses using feeding trials in two regions with high white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) densities: Outaouais and Anticosti Island (Quebec, Canada). In each, we selected a species of interest and compared browsing rates and time spent foraging with neighbours relatively preferred or avoided. In a subexperiment, we included coyote (Canis latrans Say, 1823) urine to test f…
Host plant use by the Heath fritillary butterfly, Melitaea athalia : plant habitat, species and chemistry
2008
We present a study of habitat use, oviposition plant choice, and food plant suitability for the checkerspot butterfly Melitaea athalia Rottemburg (Lepidoptera: Nymphalidae) in Aland, Finland. We found that in Aland, unlike in the mainland of Finland and many parts of its range, M. athalia flies mainly in open meadows. When offered an array of plants in a large (32 × 26 m) field cage, they predominately oviposited upon Veronica chamaedrys L., V. spicata L. and Plantago lanceolata L. (Plantaginaceae), which grow in open meadows. The relative abundance of the butterfly in Aland, and its habitat and host plant use there, may reflect local adaptation to land use practices and geology that mainta…
The Plant as a Habitat for Entomophagous Insects
2017
International audience; Populations of herbivorous insects are naturally consumed by other predacious or predatory insect species. These entomophagous insects are thus plant-dwelling organisms that use the plant for several vital functions and are affected by plant traits at the evolutionary, organism and population levels. Many entomophagous species are used for the biological control of insect pests worldwide. The aim of this chapter is to provide an exhaustive review of mechanisms underlying the interactions between plants and entomophagous insects, including those governing life history traits at the individual level, as well as those acting on population and community structure and dyn…
Variation in Hsp70 Levels after Cold Shock: Signs of Evolutionary Responses to Thermal Selection among Leptinotarsa decemlineata Populations
2012
Individuals of widely spread species are expected to show local adaption in temperature tolerance as they encounter a range of thermal conditions. We tracked thermal adaptations of the Colorado potato beetle (Leptinotarsa decemlineata) that invaded Europe within the last 100 years. It has occupied various conditions although, like the majority of invasive species, it lost a measurable amount of neutral genetic variation due to bottleneck effect when it invaded Europe. We exposed diapausing beetles originated from three different latitudes (54°N, 59°N, 60°N) to cold shock (−5°C, 1.5 hrs) in order to test if beetles from the northern populations express differential levels of cold-induced and…
An annotated checklist of freshwater Copepoda (Crustacea, Hexanauplia) from continental Ecuador and the Galapagos Archipelago.
2019
An annotated checklist of the free-living freshwater Copepoda recorded in different regions in Ecuador (including the Amazon, the Andes, the coastal region, and the Galapagos Islands) is here provided. We revised all published records, critically evaluated the validity of each taxon and provided short taxonomic and biogeographical remarks for each one. A total of 27 taxa have been reported, including species and records at the generic level only. The species and taxa identified only up to the generic level belong to five families and 14 genera. The Cyclopoida is the most diverse group with 16 records belonging to species (or identified to the generic level only) and eight genera, followed b…