## 3 Results
### Parasitism of Planthopper and Leafhopper Eggs  
Egg laying by planthopper was not affected by variety and was consistent between the two seasons that we used sentinel plants (Table S1). BPH laid 100.15 \(\pm\) 4.03 eggs per plant; WBPH laid 65.92 \(\pm\) 5.25 eggs per plant. All three hoppers tended to lay more eggs in nitrogen-fertilized plants, but the effects were only significant for GLH (\(\chi^{2}\) = 8.372, \(p\) < 0.01). During our experiments, GLH laid significantly fewer eggs during the wet season experiments (DS = 101.53 \(\pm\) 15.00; WS = 19.93 \(\pm\) 3.75: \(\chi^{2}\) = 62.987, \(p\) < 0.001) (Table S1). Eggs maintained in the screenhouse were not parasitized, indicating that all reported parasitism occurred during field exposures.  
Egg parasitoids caused 31.04 \(\pm\) 4.01% mortality of BPH eggs during the dry season and 38.88 \(\pm\) 2.96% during the wet season exposures. There was no effect of nitrogen (\(\chi^{2}\) = 3.110, \(p\) > 0.05) on parasitism levels. There was a significant season-variety interaction (4.293, \(p\) = 0.038) because of higher parasitism of eggs in IR64 than IR62 during the wet season exposure, but not during the dry season (Figure 2A,B).  
Parasitism of WBPH eggs was lower in the dry season (23.63 \(\pm\) 3.98%) than the wet season (51.96 \(\pm\) 4.81%) (\(\chi^{2}\) = 12.666, \(p\) < 0.001: Figure 2B,C). There was a tendency toward higher parasitism of WBPH eggs in high-nitrogen plots. However, the three-way [season-variety-nitrogen] interaction was significant (\(\chi^{2}\) = 4.871, \(p\) = 0.027) (Figure 2C,D).  
Parasitism of GLH eggs was low during the dry season exposure (7.08 \(\pm\) 2.23%), with a non-significant increase during the wet season exposure (26.83 \(\pm\) 6.71%: \(\chi^{2}\) = 1.607, \(p\) = 0.209) (Figure 2E,F). _Oligosita_ spp. (mainly \(O\). sp. nr _aesopi_) were the main parasitoids. In both seasons, egg parasitism was higher on IR62 plants under low nitrogen, but higher on IR64 plants under high nitrogen (\(\chi^{2}\) = 15.852, \(p\) < 0.001: Figure 2C,D). We will not consider  
Figure 2: Effects of nitrogen (0 or 150 kg ha\({}^{-1}\) of nitrogen) and variety (IR62: resistant and IR64: susceptible) on percentage parasitism of BPH (**A**,**B**), WBPH (**C**,**D) and GLH (**E**,**F) eggs in rice field plots. Experiments were conducted during the dry (**A**,**C**,**E) and wet (**B**,**D**,**F) seasons of 2013. Standard errors are indicated (N = 6); results of GLM are indicated as ns = \(p\) > 0.05, \({}^{*}\) = \(p\)\(\leq\) 0.05 and \({}^{***}\) = \(p\)\(\leq\) 0.001. BPH = brown planthopper, WBPH = whitebacked planthopper, and GLH = green leafhopper; S = season, N = nitrogen and V = variety.  
parasitism of GLH eggs further in this study because of low parasitism rates during the dry season exposure and low numbers of eggs laid in sentinel plants in the wet season (Table S1).  
Parasitism rates of WBPH (\(\chi^{2}\) = 32.814, \(p\) \(<\) 0.001) and BPH (\(\chi^{2}\) = 13.168, \(p\) \(<\) 0.001) eggs by _Anagrus_ spp. were significantly higher during the wet season compared to the dry season exposure (\(\chi^{2}\) = 13.168, \(p\) \(<\) 0.001: Figure 3A,B). A higher proportion of BPH eggs were parasitized on IR64 compared to IR62 (\(\chi^{2}\) = 6.527, \(p\) \(<\) 0.01), but the same variety effect did not occur for WBPH eggs (\(\chi^{2}\) = 0.570, \(p\) \(>\) 0.5: Figure 3A,B).  
Parasitism of WBPH eggs by _Oligosita_ spp. was marginally higher in the high-nitrogen plots (\(\chi^{2}\) = 4.454, \(p\) \(<\) 0.05), but the same effect did not occur for BPH eggs (\(\chi^{2}\) = 0.389, \(p\) \(>\) 0.05: Figure 3C,D). Egg parasitism by _Oligosita_ spp. was not affected by season, variety or interactions during sampling (Figure 3C,D).