Search results for "range"

Disentangling higher trophic level interactions in the cabbage aphid food web using high-throughput DNA sequencing

2017

International audience; The lack of understanding of complex food-web interactions has been a major gap in the history of biological control. In particular, a better understanding of the functioning of pest food-webs and how they vary between native and invaded geographical ranges is of prime interest for biological control research and associated integrated pest management. Technical limitations associated with the deciphering of complex food-webs can now be largely overcome by the use of high throughput DNA sequencing techniques such as Illumina MiSeq. We tested the efficiency of this next generation sequencing technology in a metabarcoding approach, to study aphid food-webs using the cab…

Three chromosomal rearrangements promote genomic divergence between migratory and stationary ecotypes of Atlantic cod

2016

AbstractIdentification of genome-wide patterns of divergence provides insight on how genomes are influenced by selection and can reveal the potential for local adaptation in spatially structured populations. In Atlantic cod – historically a major marine resource – Northeast-Arctic- and Norwegian coastal cod are recognized by fundamental differences in migratory and non-migratory behavior, respectively. However, the genomic architecture underlying such behavioral ecotypes is unclear. Here, we have analyzed more than 8.000 polymorphic SNPs distributed throughout all 23 linkage groups and show that loci putatively under selection are localized within three distinct genomic regions, each of sev…

Phenological and intrinsic predictors of mite and haemacoccidian infection dynamics in a Mediterranean community of lizards

2021

Ectotherms are vulnerable to environmental changes and their parasites are biological health indicators. Thus, parasite load in ectotherms is expected to show a marked phenology. This study investigates temporal host–parasite dynamics in a lizard community in Eastern Spain during an entire annual activity period. The hosts investigated were Acanthodactylus erythrurus, Psammodromus algirus and Psammodromus edwardsianus, three lizard species coexisting in a mixed habitat of forests and dunes, providing a range of body sizes, ecological requirements and life history traits. Habitat and climate were considered as potential environmental predictors of parasite abundance, while size, body conditi…

Through the eye of a lizard: hue discrimination in a lizard with ventral polymorphic coloration.

2017

Colour polymorphisms are thought to be maintained by complex evolutionary processes some of which require that the colours of the alternative morphs function as chromatic signals to conspecifics. Unfortunately, a key aspect of this hypothesis has rarely been studied: whether the study species perceives its own colour variation as discrete rather than continuous. The European common wall lizard (Podarcis muralis) presents a striking colour polymorphism: the ventral surface of adults of both sexes may be coloured orange, white, yellow, or with a mosaic of scales combining two colours (orange-white, orange-yellow). Here we use a discrimination learning paradigm to test if P. muralis is capable…

Twig and Shoot Dieback of Citrus, a New Disease Caused by Colletotrichum Species

2021

(1) Background: This study was aimed at identifying the Colletotrichum species associated with twig and shoot dieback of citrus, a new syndrome occurring in the Mediterranean region and also reported as emerging in California. (2) Methods: Overall, 119 Colletotrichum isolates were characterized. They were recovered from symptomatic trees of sweet orange, mandarin and mandarin-like fruits during a survey of citrus groves in Albania and Sicily (southern Italy). (3) Results: The isolates were grouped into two distinct morphotypes. The grouping of isolates was supported by phylogenetic sequence analysis of two genetic markers, the internal transcribed spacer regions of rDNA (ITS) and β-tubulin …

DNA Taxonomy Confirms the Identity of the Widely-Disjunct Mediterranean and Atlantic Populations of the Tufted Ghost Crab Ocypode cursor (Crustacea: …

2019

The distribution area of the tufted ghost crab Ocypode cursor includes two widely separate sub-areas, i.e. the tropical and subtropical Atlantic coasts of Africa and Macaronesia, and the central-eastern Mediterranean basin. The current disjunct distribution of the species is possibly the remnant of a previous wider and continuous distribution area that was fragmented during the Pleistocene, with the disappearance of the species from the temperate Atlantic Ocean and the western Mediterranean basin, and its survival in the warmer areas of the eastern Atlantic and the Mediterranean Sea. Such disjunction is thus compatible with an ancient isolation between the Mediterranean and Atlantic populat…

Do mosses really exhibit so large distribution ranges? Insights from the integrative taxonomic study of the Lewinskya affinis complex (Orthotrichacea…

2019

The strikingly lower number of bryophyte species, and in particular of endemic species, and their larger distribution ranges in comparison with angiosperms, have traditionally been interpreted in terms of their low diversification rates associated with a high long-distance dispersal capacity. This hypothesis is tested here with Lewinskya affinis (≡ Orthotrichum affine), a moss species widely spread across Europe, North and East Africa, southwestern Asia, and western North America. We tested competing taxonomic hypotheses derived from separate and combined analyses of multilocus sequence data, morphological characters, and geographical distributions. The best hypothesis, selected by a Bayes …

How ants acclimate: Impact of climatic conditions on the cuticular hydrocarbon profile

2017

1.Organisms from temperate zones are exposed to seasonal changes and must be able to cope with a wide range of climatic conditions. Especially ectotherms, including insects, are at risk to desiccate under dry and warm conditions, the more so given the changing climate. 2.To adjust to current conditions, organisms acclimate through changes in physiology, morphology and/or behaviour. Insects protect themselves against desiccation through a layer of cuticular hydrocarbons (CHC) on their body surface. Hence, acclimation may also affect the CHC profile, changing their waterproofing capacity under different climatic conditions. 3.Here, we investigated the acclimation response of two Temnothorax a…

2020

During winter insects face energetic stress driven by lack of food, and thermal stress due to sub-optimal and even lethal temperatures. To survive, most insects living in seasonal environments such as high latitudes, enter diapause, a deep resting stage characterized by a cessation of development, metabolic suppression and increased stress tolerance. The current study explores physiological adaptations related to diapause in three beetle species at high latitudes in Europe. From an ecological perspective, the comparison is interesting since one species (Leptinotarsa decemlineata) is an invasive pest that has recently expanded its range into northern Europe, where a retardation in range expa…

Getting there and around: Host range oscillations during colonization of the Canary Islands by the parasitic nematode Spauligodon

2016

Episodes of expansion and isolation in geographic range over space and time, during which parasites have the opportunity to expand their host range, are linked to the development of host-parasite mosaic assemblages and parasite diversification. In this study, we investigated whether island colonization events lead to host range oscillations in a taxon of host-specific parasitic nematodes of the genus Spauligodon in the Canary Islands. We further investigated whether range oscillations also resulted in shifts in host breadth (i.e., specialization), as expected for parasites on islands. Parasite phylogeny and divergence time estimates were inferred from molecular data with Bayesian methods. H…