Upper: Hypselodoris bullocki and H. apolegma mating. Photo: Phil Slosberg.
Lower: Halgerda carlsoni and H. diaphana mating. Photo: Mitsuo & Ayumi Murakami.
One definition of a species is that it is a group of animals which mate with each other and produce viable off-spring. One consequence of that is that many species have evolved elaborate behavioural and anatomical barriers so that species mate only with their own kind. When two apparently different species are observed mating it is an event of some interest. It means either that our definition of the species involved is faulty, or that the methods these species use to identify their own kind is faulty. A number of such observations have been made by Forum contributors and links to their messages are listed below. See also some general messages below.
• Chelidonura amoena & C. electra - Possible hybrid
• Chromodoris annae & C. cf. colemani mating?
• Hypselodoris bullocki and H. apolegma mating.
• Hypselodoris sp and H. apolegma mating.
• Risbecia tryoni & R. pulchella trailing. message 1, message 2.
• Halgerda carlsoni and H. diaphana mating. [see second message.]
• Phyllidia ocellata - colour forms? mating
• Phyllidia ocellata & P. babai mating.
Rudman, W.B., 2003 (April 7) Cross-species matings. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/abmating
Re: Cross-species breeding
From: Cynthia Trowbridge, April 26, 2006
Cross-species breeding - Sea Hares
From: Jasmine Peters, March 8, 2006
From: Bill Rudman, April 9, 2003
From: Samuel K. Moore, March 8, 2003
Re: Mating behaviour
From: Hans Tibboel, March 3, 2003
From: Hans Tibboel, February 25, 2003
Re: H. bullocki 'colour forms' mating
From: Erwin Koehler, August 6, 2002