Browsing by Author "Balanika, Katerina"
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- Comparative phylogeography of endemic Azorean arthropodsPublication . Parmakelis, Aristeidis; Rigal, François; Mourikis, Thanos; Balanika, Katerina; Terzopoulou, Sofia; Rego, Carla; Amorim, Isabel R.; Crespo, Luís C.; Pereira, Fernando E. A.; Triantis, Kostas A.; Whittaker, Robert J.; Borges, Paulo A. V.BACKGROUND: For a remote oceanic archipelago of up to 8 Myr age, the Azores have a comparatively low level of endemism. We present an analysis of phylogeographic patterns of endemic Azorean island arthropods aimed at testing patterns of diversification in relation to the ontogeny of the archipelago, in order to distinguish between alternative models of evolutionary dynamics on islands. We collected individuals of six species (representing Araneae, Hemiptera and Coleoptera) from 16 forest fragments from 7 islands. Using three mtDNA markers, we analysed the distribution of genetic diversity within and between islands, inferred the differentiation time-frames and investigated the inter-island migration routes and colonization patterns. RESULTS: Each species exhibited very low levels of mtDNA divergence, both within and between islands. The two oldest islands were not strongly involved in the diffusion of genetic diversity within the archipelago. The most haplotype-rich islands varied according to species but the younger, central islands contributed the most to haplotype diversity. Colonization events both in concordance with and in contradiction to an inter-island progression rule were inferred, while a non-intuitive pattern of colonization from western to eastern islands was also inferred. CONCLUSIONS: The geological development of the Azores has followed a less tidy progression compared to classic hotspot archipelagos, and this is reflected in our findings. The study species appear to have been differentiating within the Azores for <2 Myr, a fraction of the apparent life span of the archipelago, which may indicate that extinction events linked to active volcanism have played an important role. Assuming that after each extinction event, colonization was initiated from a nearby island hosting derived haplotypes, the apparent age of species diversification in the archipelago would be moved closer to the present after each extinction-recolonization cycle. Exploiting these ideas, we propose a general model for future testing.
- Development of 28 polymorphic microsatellite markers for the endemic Azorean spider Sancus acoreensis (Araneae, Tetragnathidae)Publication . Parmakelis, Aristeidis; Balanika, Katerina; Terzopoulou, Sofia; Rigal, François; Beasley, Rochelle R.; Jones, Kenneth L.; Lance, Stacey L.; Whittaker, Robert J.; Triantis, Kostas A.; Borges, Paulo A. V."We isolated and characterized a total of 28 microsatellite loci from Sancus acoreensis. Loci were screened in 26 individuals originating from seven (Flores, Faial, Pico, São Jorge, Terceira, São Miguel, and Santa Maria) out of the nine islands of the Azores. The number of alleles per locus ranged from 2 to 14, observed heterozygosity ranged from 0.040 to 0.708, and the probability of identity values ranged from 0.02 to 0.97. Sancus acoreensis is a Laurel forest specialist species, endemic to the Azores, and is facing a great extinction risk due to the severe fragmentation of its habitat. The newly developed microsatellite loci will aid in detecting signs of population bottlenecks and pinpoint the island populations that are facing the greatest risk of extinction. […]".