Research On Influence Of Temperature,Humidity And Food Color On Body Color Of Lepidopteran Noctuidae Larvae

It's a common natural phenomenon that insect body color changes with environmental conditions. Lots of researchers think that it's a result of organic evolution and natural selection, its meaning is to enhance the ability of avoiding predators, trapping food and resisting the hostile environment, and then increasing the competitive strength of the organism itself. Although, there are many studies reported that environment is the important reason which changes the insect body color, there are few studies to research the relationship between environmental parameters and body color. The study taking the Helicoverpa armigera and Spodoptera litura larva as an example, ascertains by measuring separately the color component value (red, green, blue and lightness value) of each individual using central composite design method, by using the computer vision technology and color component technology, and study the quantitative analysis of the relationship between the color components value and the temperature, humidity, food color. The research study the influence on three environmental parameters to the body color of Helicoverpa armigera and Spodoptera litura larva, the result shows:1. The temperature has influence on the body color differentiation of the Helicoverpa armigera larva. The larvae body color value decreased with the increase of age in the suitable temperature (30.5 ?) condition. The larvae R, G, B and L value increased with the increase of temperature at age of 1-3. It shows a linear relationship.2. The R, G, L value of Helicoverpa armigera larvae body color has the significant difference under the different humidity, but there was no significant difference on the B value of color. The larvae body color increased with the increase of temperature at age of 1-3; in the higher age of larva, all indexes of larvae color value will decrease to a stable level in the high humidity environment, larvae color value will increase with the increase of age in the low humidity environment.3. When they are under the high temperature, Helicoverpa armigera larva have similar value of body colors and when under the appropriate temperature and humidity, their body color varies. Temperature, humidity and stadium has different influence in value of larva's body colors and the contribution rate sequence of regression equation is:Temperature> stadium>humidity. In a other word, temperature has biggest influence in the value of larva's body.4. Change of Spodoptera litura larva body color was also affected by food colors, and the significant impact was observed at 1-7 days. Red prototypical food r:g:b=(128?251): (3-129):(6-96) affected the most various parts of larvae body color, compared with yellow, green and purple prototypical food; being fed on different color of food, the order of coefficient of variation in different parts of the larvae was:zebra> chest and abdomen> head> dorsal mid-line.