How may climate warming affect the interspecific competition between native and invasive Pieris butterflies on two common host plants?
Date Issued
2015
Date
2015
Author(s)
Lin, Zheng-Hong
Abstract
Climate warming can affect plant-herbivore interactions directly or indirectly. Numerous studies have demonstrated direct or indirect warming effects separately, but relative few studies examine direct and indirect warming effects simultaneously on plant-herbivore interactions. Besides warming, invasive species also significantly affect plant-herbivore interactions, such as via their competition against native herbivores for food resource. However, little is known about how the competition between native and invasive species might be affected by climate warming. To understand how warming will directly and indirectly affect plant-herbivore interactions, and whether warming will change the competitive status between native and invasive herbivores, this study examined two competing butterfly species of Taiwan (the native Pieris canidia and the invasive P. rapae) on their two common host plants- variableleaf yellowcress (Rorippa indica) and cabbage (Brassica oleracea var. capitata) in 3 environmental chambers (18.5, 21.5, 24.5°C). The chamber at 18.5 °C served as control, reflecting the average monthly temperature when both butterflies became abundant in the field; the one at 21.5 or 24.5 °C simulated 3 or 6 °C warming, respectively. Each chamber included four treatments, allowing us to examine the intra- and inter-specific competition: a) 4 P. canidia, b) 2 P. canidia and 2 P. rapae, c) 4 P. rapae larvae on a host plant, and d) a host plant only. As for the results in plant traits, warming affected the quantity and quality of both host plants in a similar or different fashion. For example, warming increased the leaf number in both R. indica and B. oleracea plants. However, warming reduced the C/N ratio (an important plant quality index for herbivore performance) in R. indica but not in B. oleracea. As for the performance of each herbivore species, warming effects were host plant dependent. In the R. indica plant system, warming increased the developmental rate and body size of both Pieris species. The larger body size could be contributed by an indirect warming effect (i.e. warming increased plant nitrogen content and consequently, indirectly benefited Pieris). In the cabbage plant system, warming, however, increased the developmental rate of both Pieris and reduced the body size of P. canidia.. As for herbivore competition, warming effects was host plant dependent. In the R. indica plant system, the native P. canidia, facing stronger intraspecific than interspecific competition, had a competitive advantage over the invasive P. rapae under ambient temperature. However, the advantage for the native Pieris disappeared under warming. In the cabbage plant system, the invasive P. rapae had a competitive advantage over the native P. canidia. The advantage for the invasive Pieris sustained under warming, differently from the pattern in Rorippa indica plant system. This study shows that warming may affect performance of herbivores (i.e. Pieris) directly via growth and development, and indirectly via host plant quality or the competitive outcome against other herbivores. This study also suggests that warming could shift the current competitive status between native and invasive herbivores (e.g. P. canidia vs. P. rapae), likely changing many plant and animal communities worldwide.
Subjects
Brassica oleracea var. capitata
climate warming
invasive species
Pieris canidia
Pieris rapae
Rorippa indica
interspecific competition
SDGs
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-104-R00b44014-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):bc45decf30a39c35cef42692b6879af0