Is Glue Production by Seeds of Salvia Columbariae a Deterrent to Desert Granivores?

With a few notable exceptions (Borchert and Jain 1978, Inouye et at. 1980, O'Dowd and Hay 1980, Hay and Fuller 1981), most ecological studies on seed-granivore interactions in arid communities have concentrated on the adaptations and ecology of the granivores and not on characteristics of the seeds that may deter granivory. Since a large portion of the annual seed crop of many desert ephemerals is lost to seed predators (Chew and Chew 1970, French et al. 1974, Nelson and Chew 1977, Brown et al. 1979), characteristics that significantly reduce losses to granivores should be strongly selected. In this paper we show that under natural conditions seeds of the desert annual Salvia columhariae produce a glue-like substance when wetted that strongly binds sand grains to the seeds, and that seeds thus covered by sand suffer significantly less loss to desert granivores.