Warming, nitrogen deposition and provenance shift above-belowground insect interactions and host compensatory growth

Above-belowground insect herbivore interactions and plant compensatory
growth are crucial for reshaping the fitness of invasive plants, and it is
likely that climate warming, nitrogen (N) deposition, and plant provenance
influence this interaction and growth in a complex way. We performed an
experiment with Solidago canadensis from home and introduced ranges,
leaf-chewing Spodoptera litura, and root-feeding Protaetia brevitarsis
under climate warming and N deposition, and addressed how these abiotic
stressors and plant provenance jointly shaped the reciprocal effects
between S. litura and P. brevitarsis and the compensatory growth of S.
canadensis after herbivory. Under ambient conditions, S. litura and P.
brevitarsis inhibited each other on the basis of growth; warming, N
addition or warming plus N addition shifted or even reversed this
competition depending on provenance. While the survival-based
above-belowground interactions differed from growth-based ones, warming or
warming plus N addition also shifted or even reversed the neutralism or
amensalism detected under ambient conditions depending on provenance.
Solidago canadensis from its home range was more tolerant of herbivory
than from its introduced range under ambient conditions; warming, N
addition or warming plus N addition decreased the plant compensatory
growth of native S. canadensis, but increased that of invasive S.
canadensis relative to ambient conditions. These findings suggest that
climate warming and N deposition could enhance positive above-belowground
insect interactions, increasing insect pressures on S. canadensis, and
that plant provenance might be important in mediating climate change
effects on insect interactions and host compensatory growth under plant
invasions.