Search results for "sympatric speciation"
showing 10 items of 101 documents
Maintenance of male reaction to the congeneric song in the Hippolais warbler hybrid zone
1999
Both hybridization and competition may induce character shift on communication systems in hybrid zones, leading either to convergence or divergence. Melodious warblers Hippolais polyglotta and Icterine warblers H. icterina are interspecifically territorial and hybridize along a narrow contact zone. This spatial distribution is favoured by a reaction to the congeneric song. A character displacement, e.g. a decrease of the reaction, was expected within the hybrid zone because of reproduction costs lower than in allopatry. We investigated the pattern of variation of the interspecific reaction by comparing allopatric and sympatric populations. However, our data did not support the hypothesis ch…
Selection on size and secondary sexual characters of the damselfly Calopteryx splendens when sympatric with the congener Calopteryx virgo
2011
Male mating success is often determined by body size or secondary sexual characters because of female mate choice or competition for females. In addition to intraspecific interactions, interspecific interactions may interfere with intraspecific selection. In this study, we investigated sexual selection on size and sexual characters of male banded demoiselle ( Calopteryx splendens (Harris, 1780)) in wild populations sympatric with the beautiful demoiselle ( Calopteryx virgo (L., 1758)). As secondary sexual characters, male C. splendens have pigmented wing spots whose size appears to be under positive selection. Male C. virgo resemble male C. splendens that have the largest wing spots, leadi…
Phylogeographic patterns of host-race evolution in Tephritis conura (Diptera: Tephritidae)
2006
Host-race evolution is a prime candidate for sympatric speciation because host shifts must take place in the presence of both hosts. However, the geographic context in which the shift takes place may have strong allopatric or peripatric components if the primary host within a localized area is scarce or even goes extinct. Inference of the relative importance of the geographic mode of speciation may be gained from phylogeographic imprints. Here, we investigate the phylogeography of host races of the tephritid fly Tephritis conura from sympatric, parapatric and allopatric populations of Cirsium heterophyllum and Cirsium oleraceum (Asteraceae) in Europe, for addressing the age and direction, a…
Review paper: Ecological genetics of Brachionus sympatric sibling species
1998
In this paper we review previous studies on sympatric Brachionus populations in Torreblanca Marsh as a model of evolutionary and ecological relationships between closely related species. The marsh is a wetland on the Mediterranean coast of Spain with high spatial and temporal heterogeneity. Allozyme and morphometric analysis showed that Brachionus group plicatilis (formerly, Brachionus plicatilis and currently split into B. plicatilis and B. rotundiformis) was composed of three groups of genotypes with no evidence of gene flow between them (B. plicatilis, B. rotundiformis SM and B. rotundiformis SS). Correlations between seasonal and spatial distributions, on one hand, and temperature and s…
Crossed induction of sex in sympatric congeneric rotifer populations
2009
The transition from asexual to sexual reproduction in rotifers of the genus Brachionus (Monogononta) is triggered by a chemical signal produced and released by the rotifers themselves; the signal accumulates in the environment as population density increases. The response to this signal has been hypothesized to be speciesspecific. If not, the timing of sex and final diapausing egg production of a species might not be optimized. In this study, a set of experiments—based on individual and mass culture approaches—was carried out to investigate the differentiation in sex induction signals between sympatric and allopatric congeneric Brachionus populations by analyzing the capability of the mediu…
Reviergesänge und Speziesdifferenzierung in der Klappergrasmücken-GruppeSylvia [curruca]
1997
Territorial songs of the nearly trans-PalaearcticSylvia curruca complex recorded in various area parts of the three major taxa groups (curruca, althaea, minula) are analyzed. Playback experiments substantiate the differences between the three groups. In view of their locally sympatric distribution and distinct territorial songs thecurruca, althaea andminula groups are considered different species of superspeciesSylvia [curruca].
Speciation via Differential Host–Plant Use in the Tephritid Fly Tephritis conura
2010
The close association between phytophagous insects and host plants and the possibility for specialization on new plants make phytophagous insects prime candidates for sympatric speciation via host-race evolution. In this chapter, we summarize results addressing host-race evolution in the tephritid fly Tephritis conura (Tephritidae) infesting Cirsium heterophyllum and C. oleraceum (Asteraceae). Host plant distributions in allopatry, sympatry and parapatry, and different infestation patterns enabled us to test geographic speciation scenarios, investigate adaptations, and address the importance of plant population history for diversification of T. conura.
LOCAL ADAPTATION, RESISTANCE, AND VIRULENCE IN A HEMIPARASITIC PLANT-HOST PLANT INTERACTION
2000
Coevolution may lead to local adaptation of parasites to their sympatric hosts. Locally adapted parasites are, on average, more infectious to sympatric hosts than to allopatric hosts of the same species or their fitness on the sympatric hosts is superior to that on allopatric hosts. We tested local adaptation of a hemiparasitic plant, Rhinanthus serotinus (Scrophulariaceae), to its host plant, the grass Agrostis capillaris. Using a reciprocal cross-infection experiment, we exposed host plants from four sites to hemiparasites originating from the same four sites in a common environment. The parasites were equally able to establish haustorial connections to sympatric and allopatric hosts, and…
Disentangling canid howls across multiple species and subspecies: Structure in a complex communication channel
2016
Wolves, coyotes, and other canids are members of a diverse genus of top predators of considerable conservation and management interest. Canid howls are long-range communication signals, used both for territorial defence and group cohesion. Previous studies have shown that howls can encode individual and group identity. However, no comprehensive study has investigated the nature of variation in canid howls across the wide range of species. We analysed a database of over 2000 howls recorded from 13 different canid species and subspecies. We applied a quantitative similarity measure to compare the modulation pattern in howls from different populations, and then applied an unsupervised clusteri…
Confrontation of cryptic diversity and mate discrimination within Gammarus pulex and Gammarus fossarum species complexes.
2014
16 pages; International audience; Freshwater amphipods Gammarus fossarum and Gammarus pulex are widespread in Europe, with some evidence of cryptic diversity in the former. We used DNA barcoding to assess genetic diversity within and among amphipod populations and examined mate discrimination and pre-copulatory pair formation between genetically divergent individuals. Eight distinct G. fossarum and four distinct G. pulex molecular operational taxonomic units (MOTUs) were detected. Among the 33 amphipod populations sampled, 11 contained a single MOTU, 11 had two and 11 were composed of three sympatric MOTUs. Genetic divergences between sympatric MOTUs (G. fossarum and G. pulex MOTUs combined…