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- Jouventin, P A, et al.
(författare)
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Genetic isolation and divergence in sexual traits: evidence for the northern rockhopper penguin Eudyptes moseleyi being a sibling species
- 2006
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Ingår i: Molecular Ecology. - 0962-1083. ; 15:11, s. 3413-3423
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Tidskriftsartikel (refereegranskat)abstract
- The taxonomic status of populations of rockhopper penguins (Eudyptes chrysocome) is still enigmatic. Northern populations differ from southern ones in breeding phenology, song characteristics and head ornaments used as mating signals. We conducted a molecular analysis using mitochondrial DNA sequencing to test if there is a gene flow barrier between northern (subtropical) populations and southern (subantarctic) populations in relation to the Subtropical Convergence, a major ecological boundary for marine organisms. Sequences of the control region and the ND2 gene were analysed in rockhopper penguins and in the macaroni penguin (Eudyptes chrysolophus), a closely related species. Genetic distances and phylogenetic analyses showed a clear split into three clades, two rockhopper clades and the macaroni penguin. Moreover, Theta(ST) and gene flow estimates also suggested genetic structuring within the northern rockhoppers. Our results add further support to the notion that the two rockhopper penguin taxa, often considered as two subspecies, can be recognized as two species E. chrysocome and E. moseleyi. The divergence in mating signals found between these two taxa seems to have occurred recently and relatively rapidly. Thus, the behavioural changes may have been enough to isolate these taxa without the need for morphological differentiation. The findings have important conservational implications, since E. moseleyi is far less abundant than E. chrysocome, but more populations may warrant an uplisting to endangered status if full species status should be recognized for more subpopulations.
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- Pakanen, V. M., et al.
(författare)
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Low frequencies of supernormal clutches in the Southern Dunlin and the Temminck's Stint
- 2019
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Ingår i: Ardea. - : Netherlands Ornithologists' Union. - 0373-2266. ; 107:1, s. 61-74
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Tidskriftsartikel (refereegranskat)abstract
- Supernormal clutches are found across bird species. Such clutches often result from more than one female laying eggs in the same nest and can reflect different behaviours from parasitism to laying mistakes. Enlarged clutches are readily visible among waders due to a maximum maternal clutch size of four eggs, yet surprisingly little is known about this phenomenon. Since supernormal clutches are rare, large sample sizes are required to reliably quantify their natural frequencies. We used a large dataset to estimate the frequency of supernormal clutches in the polygamous Temminck's Stint Calidris temminckii and the monogamous Southern Dunlin C. alpina schinzii, and examine the timing of supernormal clutches in relation to the general distribution of nest initiation dates. While supernormal clutches were very rare, they were over four times more common in the Temminck's Stint (0.50%, n = 1594) than in the Southern Dunlin (0.11%, n = 2766). Dunlin show among the lowest frequency of supernormal clutches reported for waders. In the Temminck's Stint, supernormal clutches were found in the middle of the season, while in the Southern Dunlin such clutches occurred in late season replacement nests. The higher rate and timing of enlarged clutches in Temminck's Stints probably relates to the species' breeding system, which can include simultaneous courtship of multiple partners, but more work is needed to assess the relative influence of different factors. We argue that intraspecific nest parasitism is unlikely to be a primary reproductive tactic in small sandpipers.
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