Reproductive Isolation and Ecological Niche Partition among Larvae of the Morphologically Cryptic Sister Species Chironomus riparius and C. piger

摘要: Background One of the central issues in ecology is question what allows sympatric occurrence closely related species same general area? The non-biting midges Chironomus riparius and C. piger, interbreeding laboratory, have been shown to coexist frequently despite their close relatedness, similar high morphological similarity. Methodology/Principal Findings In order investigate factors shaping niche partitioning these cryptic sister species, we explored actual degree reproductive isolation field. Congruent results from nuclear microsatellite mitochondrial haplotype analyses indicated complete absence interspecific gene-flow. Autocorrelation analysis showed a non-random spatial distribution two species. Though not dispersal limited at scale study area, occurred less often than expected site, indicating past or present competition. Correlation multiple regression suggested repartition available habitat along water chemistry gradients (nitrite, conductivity, CaCO3), ultimately governed by differences summer precipitation regime. Conclusions We show that morphologically partition niches due certain ecological distinctness total coexistence provides suitable model system for investigation related,