Effects of insect infestation on Quercus aliena var. acuteserrata acorn dispersal in the Qinling Mountains, China

摘要

The nutritious acorns produced by oak trees (Quercus spp.) are attacked frequently by insects that feed on seed reserves. However, previous studies have partly considered the effects of insect infestations on animal seed dispersal and subsequent plant regeneration. In this study, we tested whether the effects of insect infestations on seed dispersal were frequency dependent (i.e., ratio of noninfested to infested acorns). We tracked the seed dispersal of plastic-tagged noninfested and insect-infested Q. aliena var. acuteserrata acorns with different frequencies in the Qinling Mountains in central China. Our results demonstrated that noninfested acorns were removed more rapidly, regardless of the infestation rates. Insect-infested acorns were also more likely to be eaten in situ, whereas noninfested acorns were more likely to be scatter-hoarded independent of infestation rates. Moreover, noninfested acorns were dispersed further and had higher survival rates than insect-infested acorns. Our findings suggest that the seed dispersal advantages of noninfested acorns compared with infested acorns was not frequency dependent, thereby indicating a consistently higher dispersal likelihood of noninfested acorns.