Cichlid fish diversity threatened by eutrophication that curbs sexual selection

Science

Volumn 277, Issue 5333, 1997, Pages 1808-1811

  Seehausen, Ole ^a   Van Alphen, Jacques J M ^a   Witte, Frans ^a  

^a LEIDEN UNIVERSITY   (Netherlands)

Author keywords

[No Author keywords available]

Indexed keywords

COLOUR MORPH; EUTROPHICATION; HUMAN ACTIVITY; MATE CHOICE; SEXUAL SELECTION; SPECIES DIVERSITY; TURBIDITY;

ARTICLE; BIODIVERSITY; COLOR VISION; EUTROPHICATION; FISH; GENETIC ANALYSIS; NONHUMAN; PHYLOGENY; PREDATION; PRIORITY JOURNAL; REPRODUCTION; RESOURCE ALLOCATION; SEX DIFFERENTIATION;

AFRICA, LAKE VICTORIA;

EID: 0030874938     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.277.5333.1808     Document Type: Article

References (65)

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22. 2 hybrids as well as in both parental species. M. D. Crapon de Caprona and B. Fritzsch [Neth. J. Zool. 34, 503 (1984)] found no difference in fertility between Astatotilapia nubila × Haplochromis "black lividus" hybrids and the parent species. Three further laboratory hybridizations that we did and three done elsewhere [M. D. Crapon de Caprona, Ann. Mus. R. Afr. Cent. Sci. Zool. 251, 117 (1996)] yielded viable and, where tested (two intergeneric crosses in our lab), fertile offspring. Successful hybridization between genera of haplochromine cichlids, resulting in viable offspring, has also been reported from Lake Malawi [J. R. Stauffer, N. J. Bowers, T. D. Kocher, K. R. McKaye, Copeia (1996), p. 203].
23. 2 hybrids as well as in both parental species. M. D. Crapon de Caprona and B. Fritzsch [Neth. J. Zool. 34, 503 (1984)] found no difference in fertility between Astatotilapia nubila × Haplochromis "black lividus" hybrids and the parent species. Three further laboratory hybridizations that we did and three done elsewhere [M. D. Crapon de Caprona, Ann. Mus. R. Afr. Cent. Sci. Zool. 251, 117 (1996)] yielded viable and, where tested (two intergeneric crosses in our lab), fertile offspring. Successful hybridization between genera of haplochromine cichlids, resulting in viable offspring, has also been reported from Lake Malawi [J. R. Stauffer, N. J. Bowers, T. D. Kocher, K. R. McKaye, Copeia (1996), p. 203].
24. 2 hybrids as well as in both parental species. M. D. Crapon de Caprona and B. Fritzsch [Neth. J. Zool. 34, 503 (1984)] found no difference in fertility between Astatotilapia nubila × Haplochromis "black lividus" hybrids and the parent species. Three further laboratory hybridizations that we did and three done elsewhere [M. D. Crapon de Caprona, Ann. Mus. R. Afr. Cent. Sci. Zool. 251, 117 (1996)] yielded viable and, where tested (two intergeneric crosses in our lab), fertile offspring. Successful hybridization between genera of haplochromine cichlids, resulting in viable offspring, has also been reported from Lake Malawi [J. R. Stauffer, N. J. Bowers, T. D. Kocher, K. R. McKaye, Copeia (1996), p. 203].
25. All haplochromines, the retina of which has been studied, have one absorbance peak on blue and one on yellow to red [H. J. van der Meer and J. K. Bowmaker, Brain Behav. Evol. 45, 232 (1995)].
26. We have recorded seven sympatric blue/yellow-red sibling species pairs in three genera of rock-restricted haplochromines (7) and many more in eight genera that inhabit other habitats [for example, R. J. C. Hoogerhoud, F. Witte, C. D. N. Barel, Neth. J. Zool. 33, 283 (1983)]. We have also found blue and yellow-red sympatric male color morphs in 11 rock-restricted species of five genera (7).
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54. We compared the male coloration of the H. nyererei population at Nyegezi rocks (Mwanza Gulf) in 1986 with that of the same population in 1993 through 1995. The red/blue ratio [610 nm/515 nm (31)] was significantly higher in the earlier year (1.18, SE = 0.14, n = 6 versus 0.75, SE = 0.17, n = 11;Z = -1.96, P = 0.05). Two males photographed in 1978 had an even higher red/blue ratio than those from 1986. Between 1986 and 1995 the water transparency at Nyegezi rocks had dropped from 3.2 to 1.2 m (11).
55. 2 = 0.82, P = 0.002.
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65. We thank the Tanzanian Government and P. O. J. Bwathondi for research permits; the Mwanza center of TAFIRI (E. F. B. Katunzi) for hospitality and support; M. Kayeba, R. Enoka, A. Samwel Terry, and M. Haluna for assistance; L. Assembe for technical realization; L. Schadhauser, A. Samwel Terry, H. Nielsen, R. Kiteri, H. G. Mbilinyi, C. C. Schaefer, G. De Leeuw, P. Swelderwaard, R. Stawikowski, and R. R. Mapunda for logistic support; T. Reimchen for discussion; K. Barel, N. Bouton, P. Brakefield, S. Collins, G. Fryer, F. Galis, J. Deutsch, T. Goldschmidt, I. Hardy, R. Lande, P. Mayhew, H. Proehl, U. Schliewen, J. Sevenster, H. Slabbekoorn, J. de Visser, and an anonymous reviewer for comments on the manuscript; and M. Brittijn for the figures. We particularly acknowledge J. Yoshimura for stimulating discussions. Supported by grants from the Netherlands Foundation for the Advancement of Tropical Research, German Cichlid Association, TETRA, EHEIM, and with diving equipment from SCUBAPRO and SEAWAY.