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title: "Are hybrid albatrosses the result of rape?  The case of Laysan and Black-foots in the Northern Pacific"
---

# Are hybrid albatrosses the result of rape?  The case of Laysan and Black-foots in the Northern Pacific

Sievert Rohwer (Department of Biology and [Burke Museum of Natural History](http://www.burkemuseum.org/), University of Washington, Seattle, USA) and colleagues have “pre-published” in the on-line open-access resource [*PeerJPrePrints*](https://peerj.com/preprints/)on the link between hybridization and rape in Black-footed *Phoebastria nigripes *and Laysan *P. immutabilis*Albatrosses.

 The paper’s abstract follows:

 “Conspecific rape often increases male reproductive success.  However, the haste and aggression of forced copulations suggests that males may sometimes rape heterospecific females, thus making rape a likely, but undocumented, source of hybrids between broadly sympatric species.  We present evidence that heterospecific rape may be the source of hybrids between Black-footed and Laysan Albatrosses (*Phoebastria nigripes,* and *P. immutabilis,* respectively).  Extensive field studies have shown that paired (but not unpaired) males of both of these albatross species use rape as a supplemental reproductive strategy.  Between species differences in size, timing of laying, and aggressiveness suggest that Black-footed Albatrosses should be more successful than Laysan Albatrosses in heteropspecific [sic] rape attempts, and male Black-footed Albatrosses have been observed attempting to force copulations on female Laysan Albatrosses.  Nuclear markers showed that six hybrids we studied were F1s and mitochondrial markers shoed that male Black-footed Albatrosses sired all six hybrids.  The siring asymmetry found in our hybrids may have long persisted because an IM analysis suggests that long-term gene exchange between these species has been from Black-footed Albatrosses into Laysan Albatrosses.  If hybrids are sired in heterospecific rapes, they presumably would be raised and sexually imprinted on Laysan Albatrosses, and two unmated hybrids in a previous study courted only Laysan Albatrosses.

 ![](https://www.acap.aq/images/stories/acap/Birds/Albatrosses/B/Black_footed/black-foot_laysan_hybrid_lindsay_young.jpg)

 Laysan-Black-footed Albatross hybrid, photograph by Lindsay Young

 [Click here](http://www.acap.aq/index.php/en/news/latest-news/1651-looking-a-little-odd-for-the-camera-hybrid-black-footed-and-laysan-albatrosses-illustrated) and [here](http://www.acap.aq/index.php/en/news/news-archive/24-2011-news-archive/810-who-gets-the-last-dance-mmhybrid-black-footed-and-laysan-albatrosses-on-the-northwestern-hawaiian-islands) to read two previous postings in *ACAP Latest New*s on hybrid Black-footed and Laysan Albatrosses.

 **Reference:**

 Rohwer, S., Harris, R.B. & Walsh, H.E. 2014.  Rape and the prevalence of hybrids in broadly sympatric species: a case study using albatrosses.  [*PeerJPrePrints*  27 pp](https://peerj.com/preprints/384v1.pdf).

 *John Cooper, ACAP Information Officer, 21 May 2014*