1. The developmental stages of leaf beetle Agelastica coerulea
The Indirect Effect of Ozone on Feeding Preferences of the Leaf Beetle Larvae Agelastica coerulea
(Coleoptera: Chrysomelidae) Fed White Birch (Betula platyphylla var. japonica)
Abu ElEla Shahenda1,2, Evgenios Agathokleous1,Cong SHI 1, Takayoshi Koike1
1.Silviculture & Forest Ecological Studies, Hokkaido University, Sapporo , Japan
2.Department of Entomology, Faculty of Science, Cairo University, Cairo 12613, Egypt　
1. Introduction
3. Conclusion
Tropospheric ozone (O₃) concentrations are increasing in East Asia because of the rapid increase of economics (Ohara, 2011)
The present O₃ concentration in Japan has a negative impact on the growth of forest tree species (Watanabe et al., 2010)
Stressed plants are more vulnerable to herbivory and lead to increase nutritional value or decrease in plant chemical defenses (White, 1974, 1984).
ozone-mediated changes in quality of leaves can result in increased or decreased herbivore performance, depending on the (Agrell et al., 2005).
Little attention has been given to the indirect effect of ozone on plant-insect interactions and leaf beetle performance.
Ozone had positive effect on the development and feeding performance of the leaf beetle larvae raised on white birch leaves.
Ozone change the palatability of the stressed plant and therefore make it susceptible to herbivore.
Finally, not all insects respond negatively to the changes in plant phenotype that are mediated by elevated ozone.
4. Results and discussion
- Nutritional indices of the 2nd, 3rd , 4th , 5th , 6th and 7th instars were calculated using standard gravimetric procedures described by WALDBAUER (1968).
Nutritional indices
The developmental stages of leaf beetle Agelastica coerulea
- Efficiency conversion of ingested food(ECI) = (G/C) × 100
- Consumption index (CI) = F/TA
■Ambient　■O₃ Error bar: SE *:p<0.05
Egg mass
Larva
Prepupa
Pupa
Adult
Experimental Location
Hokkaido University, Sapporo research forest
experiment nurseries N43.07, E141.38, 15 m a.s.l
Experimental Design
We employed 2 Ozone levels x 2 soil typesx 3 rings with 3 individual seedlings in each condition.
O3 treatment
- Free-air O₃ exposure experiment
- Ozone fumigation started from 2014
with concentration pbb.
Experimental Period
・June 2016 ～ August 2016
Experimental Insect
leaf beetle Agelastica coerulea (Coleoptera: Chrysomelidae)
Larvae were reared On White birch leaves Betula platyphylla
var. japonica from 2nd to 7th instar larvae.
Plant Material
Japanese white birch (Betula platyphylla var. japonica)
Soil Type
two soil types:
brown forest soil (BF)
volcanic ash soil (VA)
No-choice Experiment
larvae were reared inside plastic cups
(diameter 80 mm) 10 larvae/cup (3 replicates for each treatment) -
After fasting for 12 hours, they were fed one whole leaf for 24 hrs.
Fresh weight of larvae, fresh weight of leaf, weight of leaf consumed and fresh weight of faeces were recorded by analytical balance (mg)
Nutritional indices of the 2nd, 3rd , 4th , 5th , 6th, and 7th instars were calculated using Waldbaur (1968) equations.
Percentage hatchability from (May - July ) and Larval duration were recorded.
Statistics
All data were presented as mean ± SD. Data were analysed using one-way analysis of variance (ANOVA) and Duncan’s multiple range test. using SAS program (SAS INSTITUTE, 2002).
2. Materials and Methods
- Growth rate (GR) = G/TA
- Efficiency conversion of digested food (ECD) = (G/C-F) × 100
Nutritional indices
- Elevated ozone significantly (p<0.05)
decease the Growth Rate in 4th and 5th instar larvae.
The consumption index (CI) decreased gradually with advanced instars in both Ambient and elevated ozone.
- The enhanced (GR) could be due to the increased efficiency of food eaten (ECI and ECD).
- Approximate digestibility (AD) = 100 × (C-F)/C
Larval duration
Larvae fed on ozone fumigated birch leaves have comparatively prolonged larval duration under elevated ozone compared to that of the control.
Percentage hatchability
- Higher percentages (100%) of hatchability were observed during June under control condition.
Acknowledgment:
I would like to express my sincere gratitude to the Mission Sector and the Cultural Office (Embassy of Egypt, Tokyo, Japan) for funding and supporting the project. With deepest gratitude to Hokkaido University for their kind hospitality and facilities during my research. I would like also to express also my deepest appreciations to all the lab members for their keen and kind assistance.