Study on Pre-Dispersal Seed Predation by Insects in the Broad-Leaved Korean Pine Mixed Forest,Changbai Mountain
Seed predation by insects is one of the main causes of seed mortality,affecting plant population renewal and community composition.Studies of pre-dispersal seed insect predation are relatively sparse and mostly short-term studies on individual dominant species,and thus limit the understanding of pre-dispersal seed predation at community level.In this study,we analysed seed rains from 2020-2021 in the 25 hm2 broad-leaved Korean pine mixed forest plot in Changbai Mountain to investigate seed predation rates and their influencing factors.All the five studied tree seeds were subjected to insect seed predation,with large variations in seed predation rates by insects(0-33.33%)among species and collections.The annual seed predation rates by insects were 8.76%and 14.39%,respectively.The variation in seed predation rates by insects was mainly influenced by fruit type,interannual coefficient of variation in seed yield and seed mass.Fruit type had the highest model contribution value(R2=32.29%),with significantly lower insect predation rates on the seeds of fleshy fruits compared to those of dry fruits(df=1,χ2=20.76,P<0.001).The interannual coefficient of seed yield variation was significantly negatively correlated with seed predation rates by insects(df=1,χ2=13.01,P<0.001;R2=8.85%),and lighter seeds had higher predation rates(df=1,χ2=10.54,P=0.001;R2=3.79%).Moreover,tree height had a significant effect on seed predation rate by insects(df=1,χ2=6.94,P=0.008),especially in 2021,where the taller plants suffered higher seed predation rates(df=1,χ2=8.27,P=0.004).The insect predation rate on mature seeds was slightly higher than that on immature seeds(df=1,χ2=3.74,P=0.053),whereas the model contribution values for these two variables were all relatively low(all R2<1%).The effects of seed number and year on insect predation rate were not significant.This study demonstrates that pre-dispersal seed insect predation is widespread in broad-leaved Korean pine mixed forest community,further reveals the influencing factors and discusses potential operating mechanisms,and thus improves our understanding of pre-dispersal seed predation by insects and associated ecological and evolutionary significances.
seed/fruit-eating insectspre-dispersal seedsseed predationmastingseed predation rate by insects
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