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African Cichlids - How do they Communicate? - II

by George J. Reclos

As far as Hap breeding is concerned, color patterns play a key role. Males will either pronounce their bars, blotches or dots or make them disappear when in their nuptial dress. Thus, Sciaenochromis fryeri, Aulonocara stuartgranti “mbenji” and Placidochromis electra use to emphasize their melanin patterns while in their nuptial dress. Other species, like Fossorochromis rostratus, Nimbochromis venustus, N. polystigma, N. livingstoni, Chilotilapia euchilus just get an overall color cast (usually blue – with the exception of N. venustus which gets an overall yellow color) which covers (partially or totally) their melanin pattern. This change can take place in an instant – which proves that it is a “communication” signal (see photos of Placidochromis electra, taken only seconds apart). Although this is by no means a generally accepted rule, most of the Malawi non-mbuna cichlids I have kept follow two different codes. Fish with vertical bars intensify them when displaying while fishes with horizontal bars or blotches shed them and reveal a uniform appearance. It is interesting to note that some species (e.g. Scieanochromis fryeri, most Aulonocara sp. and Buccochromis lepturus) only show their vertical bars when displaying. In contrast, Cyrtocara moorii, a fish which normally shows no melanine pattern shows some blue blotches when displaying. This visual “code” has been evolved in every cichlid habitat in its own independent way. Thus, while all cichlids do some things in common or react to some stimuli with the same reaction, cichlids from different habitats seem to be largely unable to fully “understand” the code of each other. This is particularly evident in tanks which house cichlids from the New world and cichlids from the East African rift lakes.

Nimbochromis livingstoni male in the usual, not breeding dress. The blotches are clearly visible.

The same fish in nuptial dress. Note the complete absence of blotches.

Placidochromis electra in the normal, not displaying dress.

The same fish, less than 20 seconds later, diplaying. Note the intensity of the bars and the appearance of more bars on its side.

Since cichlids communicate basically by vision, do all cichlids see the same things? In species which have males (or females) which look almost identical in terms of color and shape, how do the correct pairs form? A study was recently performed9 to investigate known differences in the visual pigment spectral sensitivity of the Lake Malawi cichlids, Maylandia zebra (with peak sensitivity at 368, 488, and 533 nm) and Dimidiochromis compressiceps (peak sensitivity at 447, 536, and 569 nm). In this study it was shown that Maylandia zebra (as well as Labeotropheus fuelleborni) express a complement of genes which give them UV-shifted visual pigments, while Dimidiochromis compressiceps expresses a different set to produce a red-shifted visual system. It should be noted that further examination proved that this is not due to different genes (genetic material) but rather a result of preferential expression of different “parts” of it (subsets) by those species.

Therefore it is possible that two species which have females (or males) that look almost identical to us, may look very different to their mating pairs. Furthermore, one would expect that M.zebra and L.fuelleborni are able to see better in the blue / deep blue region (which is the color of their predators) while D.compressiceps is better “equipped” to see objects colored yellow, orange or red (which is usually the color of its pray). In the Lake this makes a tremendous difference because a red or yellow cichlid will look much “brighter” (better visible) in the eyes of a D.compressiceps when searching over Vallisneria plants for its pray. However, for us, the hobbyists two things are evident : firstly, we don’t see what our cichlids see and second, in the confinements of an aquarium, the cichlids can’t see what they are supposed to see for many reasons, lighting being one of them. It should be understood that the visual system of those fishes has been “calibrated” by mother nature to perform at its best at a range of depths, a specific surrounding, available pray and mates and of course a constant light source, the sun.

I hope this short article gives an insight to the big issue of how those beauties communicate between them. It also provides some evidence that some nasty things about the behavior are due to their genetic background and should be accepted as that by the hobbyists. Finally, it makes clear that providing them with an aquascape and overall conditions resembling as close as possible their natural habitat is not a “luxury” but a need for them.

Many thanks are due to Dr. Michael K. Oliver, Dr. Simona Santini and Andreas Iliopoulos for critically reviewing this article and for their invaluable comments.

  1. Coleman R. Cichlids and Science : Feeding Frenzy. Cichlid News, 10(1): 32-34, 2001.
  2. Boughman J.W.. Divergent sexual selection enhances reproductive isolation in sticklebacks. Nature, 411: 944-7, 2001.
  3. Ryan M.J.. Food, Song and Speciation. Nature, 409: 139-140, 2001.
  4. Dieckemann U. and Doebeli M. On the origin of species by sympatric speciation. Nature, 400: 354-7, 1999.
  5. Wirtz P. Mother species – father species : unidirectional hybridization in animals with female choice. Animal Behaviour, 58: 1-12, 1999.
  6. Orr M.R. and Smith T.B. Ecology and Speciation. Tree 13(12): 502-6, 1995
  7. Coleman R. Cichlid and Science : Speculating about species. Cichlid News, 8(4): 32-34, 1999.
  8. Seehausen O., van Alphen J.J.M. and Witte E. Cichlid Fish diversity threatened by eutrophication that curbs sexual selection. Science 277: 1808-11, 1997.
  9. Carleton KL, Kocher TD. Cone opsin genes of african cichlid fishes: tuning spectral

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