Usually lizards are considered to be insect eating. But in desert areas, the extreme climatic conditions and the fluctuating amount of food often result in interesting adaptations and relations between plants and animals, and their environment. The following is a report on one such case involving flower predation by lizards.

On the 14th November, 1973, we were camped on the few hundred metres wide coastal plain at Paposo (Lat. 25°05‘ South, Long. 70°30‘, approx.), which lies between the sea and the steeply rising coastal mountain range in the Atacama desert, Chile. Because of the extremely interesting vegetation at Paposo, various writers have published further information, such as Philippi (1860), Reiche (1907), Johnston (1929), Kummerow (1961), Follmann & Weisser (1966) and Rundel & Mahu (1975). This coastal plain is inhabited mainly by a dense population of the cactus Copiapoa haseltoniana of which the cylindrical stems are generally oriented north­wards (Mooney et. al. (1975), see figure 1).

 

Fig. 1. Copiapoa haseltoniana Backeberg in its habitat at Papaso. The ochre wool of the pad distinguishes this species from Copiapo cinerea (Phil.) Backeberg. The yellow flowers are not only visited by insects, but also predated by lizards, probably Lio/aemus p/atei platei. The lizard can be seen on the upper right plant head.

As is common in areas such as this, with coastal desert climate, the early morning was overcast. By the middle of the morning however, the cloud cover had begun to dissipate, with the sun breaking through the gaps warming the ground below. Stimulated by the warmer temperatures and/or light, the lizards came out of their hiding-places, and could be seen perch­ing on rocks where they warmed themselves in the sun‘s rays. Now insect life was also more active, with many wild bees, ants, and flies paying visits to the bright yellow flowers of the Copiapoa haseltoniana plants.

The lizards, which appeared to be Liolaemus platei platei, Ortiz (1975), soon began to visit the C. haseltoniana plants, moving agilely in between the rows of spines on the ribs. When the first lizard approached a flower of C. haseltoniana it was expected that it would remain there and prey on visiting insects. Much to our surprise, the lizard moved right onto the flower and began eating parts of it, especially the pollen laden stamens (Fig. 2). This preference could be related to a possible high nutrient (proteins?) content of the pollen. We observed the lizards repeatedly, and at no stage did they attempt to catch any of the insects that passed close by them.

Fig. 2. The herbivorous lizard on the C. haseltoniana flower. They seem to prefer to eat the stamens, but occasionally they also grasp a petal such as can be seen in the photo­graph. The lizard has a petal in its mouth. An ant can be seen at the base of the flower. While we watched, no at­tempt was made by the lizard to take this ant or any other visiting insects.

Considering the large quantity of seed still produced, together with the low germination and establishment rate that Copiapoa haseltoniana normally exhibits in its natural environ­ment, the overall impact of the predation of flowers by cf. Liolaemus platei plaitei on the population of Copiapoa haseltoniana is probably low.

Herbivory by lizards has been reported to take place in other deserts, in montane areas and higher latitudes in Chile, as well as under laboratory conditions. Liolaemus nigromaculatus has been observed eating flower buds at the localities Los Molles and Zapallar in Central Chile (F.R. Fuentes (1975)). Nevertheless, this is, to our knowledge, the first time that flower predation by lizards is reported from the Atacama Desert, and it is probable that it is a much more common phenomenon than is at present realized. Another animal which we observed feeding on flowers of C. haseltoniana were goats, which (in spite of the protection by the spine barrier) were able to successfully remove complete flowers with their tongues. The shiny black seeds are harvested by ants and sometimes the fruits are completely emptied by them. (See also Weisser (1973) and Speta (1967)).

Summary

Flower predation by lizards, Liolaemus plalei platei (lguanidae), on Copiapoa haseltoniana (Cactaceae) is reported from the locality of Paposo, Atacama Desert, Chile.

Acknowledgements

We wish to acknowledge the support received from the Facultad de Ciencias, Universidad de Chile, Santiago, from the Botanical Research Institute, Pretoria, and to our travelling com­panions Prof. H. Mooney and Mrs S. Gulmon. For their valuable suggestions we want to thank Dr F.R. Fuentes, Prof. J.C. Ortiz, and Mr T. Arnold.

References

Backeberg, C. (1970). Das Kakteenlexikon. Ed. G. Fischer Verlag, Jena.

Donoso Barros, R. (1966). Reptiles de Chile. Ed. Universidad de Chile, Santiago (in Ortiz 1973)).

Follmann, G., & Weisser, P.J. (1966). Oasis de neblina en eI Norte de Chile. Bol. Univ. de Chile 67:34—38.

Fuentes, F. R. (1975). Personal communication.

Johnston, I.M. (1929). The coastal flora of the Departments of Chañaral and Taltal. Contr. Gray Herb. 85:1—1 80.

Kummerow, J. (1961). Nebelpflanzen am Rande der Wüste Atacama. Kosmos 7:319—323.

Mooney, H.A., P.J. Weisser & S.L. Gulmon (1975). Environmental adaptations of the Atacama Desert Cactus Copiapoa haseltoniana. Unpublished manuscript.

Ortiz, J.C. (1973). Nota distributional sobre Liolaemus platei platei Werner (S—uamata: Iguanidae). Anales del Museo de Historia Natural de Valparaiso 6:75—77.

Ortiz, J.C. (1975). Personal communication. Philippi, R.A. (1860). Viaje al desierto de Atacama hecho por orden del Gobierno de Chile en eI verano 1853—54. I-IV: l-236.

Rundel. P.W. & M. Mahu (1975). Community Structure and Diversity in a Coastal Fog Desert in Northern Chile. Unpublished manuscript.

Reiche. K. (1907). Grundzüge der Pflanzenverbreitung in Chile. In: Engler, A. & Drude O. Die Vegetation der Erde VIII: I —374. Leipzig.

Speta, F. (1967). Möglichkeiten der Samenverbreitung bei Cactaceen mit besonderer Berücksichtigung der Myrmekochorie. Kakt. u. a. Sukk. 10:196—198.

Weisser, P.J. (1973). Morfologia externa de las semillas de algunas cactäceas chilenas y su utilitdad en taxonomia. Anales del Museo de Historia Natural de Valparaiso 6:27—40.

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