Attractiveness Of Carbon Dioxide To White Grub And Molecular Events

Holotrichia parallela and Anomala corpulenta cause serious damages to crops in China. Treatment of grubs is mainly used chemical control, which is prone to resistance, causes soil pollution, water pollution and series of environmental problems. The new types of pollution-free methods to solve this the problem is in urgent need. We test the attractiveness of CO₂ to those beetles and their respiratory rate those share the same eating habits. Analyzed gustatory receptors of H. parallela and A. corpulenta in their gene transcript. Protaetia brevitarsis is also tested to understand their saprophagous character.Y-tube olfactometer tests were conducted to investigate taxis responses of white grub（Holotrichia parallela, Anomala corpulenta and Protaetia brevitarsis） to different concentration of CO₂ and the optimal concentration versus peanut plants. The results indicates CO₂ has the ability to lure the larvae, this behavior may relate to their eating habit. H. parallela and A. corpulenta show more interests in low concentration, P. brevitarsis can be attracted by both low and high concentration of CO₂, CO₂ is a weak attraction to attract larvae in peanut root systems.As H. parallela and A. corpulenta interests in different range of low concentration of CO₂, we take a further research in their respiratory rate under different environment control. We test their respiratory rate under 0℃、5℃、10℃、15℃、20℃、25℃、30℃ and in CO₂ concentration of 1%、6% 、 11% 、 16% 、 20%. The breathing pattern of H. parallela and A. corpulenta is the variable-amplitude oscillated type. Temperature is the main reason influencing the respiratory rate, larvae can adapt CO₂ concentration in certain limits, reduce their respiratory rates facing extreme condition. Reactions of H. parallela and A. corpulenta in different environment are similar.Data analysis based on gene transcript of H. parallela and A. corpulenta, we get 45,810 and 97,378 Unigene respectively. The Unigene length distribution proportion nearly the same, the largest length range is between 300 to 499 bp and accounted close to 50%. Comparing the Unigene number annotated to NR, Swissprot, KEG and KEGG Database, H. parallela annotated 9,913 and A. corpulenta annotated 22,042 in four Database simultaneously, and Unigene annotated in NR best-hit seemed mostly to Tribolium castaneum. According to Gene Ontology classification of the two larvae in biological process and molecular functions, they demonstrated a remarkable overall similarity. Phylogenetic tree of gustatory receptor（GRs） show three CO₂ receptors of Holotrichia parallela and two of Anomala corpulenta, which has great resemblance to Tribolium castaneum.