I tested predictions of the hypothesis that a longer seed passage time through the gut of the lizard Podarcis lilfordi enhances germination performance in the plant Withania frutescens. I compared germination success and germination time between seeds that were ingested by lizards and control seeds that were not. I also explored relationships between natural variation in seed passage time and germination performance. Germination success did not differ between ingested (63%) and non-ingested seeds (56%); there was no significant relationship between germinability and retention time. Germination time did not differ between ingested and non-ingested seeds, and was unrelated to retention time. Hence, I found no support for the hypothesis that prolonged retention times should improve germination performance. In addition, this is a pilot study stressing the importance of reptiles as seed dispersers, at least in certain habitats. (C) 2000 Editions scientifiques et medicales Elsevier SAS.

This work was supported by the Project DGICYT, PB96-0860 and PB97-1174 (to Dr A. Traveset), and by contracts of the Spanish National Science Foundation (IMEDEA, C.S.I.C.) and MEC.

Peer Reviewed