Effects Of Different Foods On Life Table Parameters And Digestive Enzyme Activities Of Frankliniella Occidentalis(Thysanoptera:Thripidae)

Frankliniella occidentalis is an important invasive pest in agricultural production.It has the characteristics of small size,strong concealment,short generation cycle and omnivorous.It has caused serious damage to horticultural crops such as vegetables and flowers.Thrips has a wide range of hosts.It can feed on tender shoots and young leaves of plants,as well as plant flowers.F.occidentalis especially prefers to feed the pollen and nectar of flowers.The rose petal,rose flower（including pollen nectar）,10%honey solution+kidney bean pod and kidney bean pod（control）were chosen as foods,the effects of different foods on the growth and development,survival rate,adult lifespan,fecundity and life parameters of F.occidentalis were studied.The differences in the nutrient contents of different foods,and the changes of digestive enzymes and nutrient contents in F.occidentalis feeding different foods with short-term and multiple generations respectively were studied too.The results of the study were as follows:1.Effects of different foods on the life parameters of F.occidentalisDifferent foods had significant effect on the growth and development,adult lifespan and oviposition of F.occidentalis at F₁,F₂,and F₃ generations.The results showed that the immature period was shorter when F.occidentalis feeding other 3 kind foods compared to feeding kidney bean pod,and the decrease degree became larger with the increase of the generation.The longevity of female adult increased too compared with thrips feeding kidney bean pod.There was not significant change among different generations when fed the same food.The developments of thrips were rose flower<10%honey solution+kidney bean pod<rose petal<kidney bean pod in each generation.The lifespan of female adults was the shortest in feeding on bean pods.The lifespan of female adults was significantly prolonged,and the lifespan of female adults was the longest when fed on rose flower and 10%honey solution+kidney bean pod.There was no significant difference in the lifespan of the male adults between feeding on rose petal and the bean pods,but the lifespan of the male adults was shorter than that of the rose flower.The fecundity of F.occidentalis feeding on different foods was in the order of rose flower>10%honey solution+kidney bean pod>rose petal>kidney bean pod.The population life parameters of the net reproductive rate（R₀）,intrinsic rate of increase（r）,and finite rate of increase（λ）of the offspring of F.occidentalis feeding on rose petal and bean pods were lower than those of feeding on rose flower and 10%honey solution+kidney bean pod.2.Effects of different foods on activity of digestive enzymes in F.occidentalisThe digestive enzyme activity in F.occidentalis changed significantly after feeding different foods at short time（1,3,6,9,12,24 and 48 h）and multiple generations（F₁,F₂,F₃,F₅,F₇ generations）.The activities ofα-amylase and trypsin in F.occidentalis feeding on the most favorite rose flower were the highest,and the activities of two enzyme were the lowest when thrips feeding rose petal at most time.The changes of chymotrypsin in F.occidentalis had no obvious regulation in a short period of time.After thrips feeding at multiple generations,theα-amylase and trypsin activities were the lowest in the 2nd instar nymphs and adults thrips fed on rose petal.In most cases,there wasn’t significant different inα-amylase and trypsin activities between thrips fed on rose flower and 10%honey solution+kidney bean pod between both 2nd instar nymph and adult.The chymotrypsin activities in 2nd instar nymph and adult thrips fed on rose flower were the highest in the F₁ and F₂ generations.The activities of chymotrypsin weren’t significant difference in 2nd instar nymph among 3 kinds of foods at the F₃,F₅ and F₇generations.The chymotrypsin activity in adult was the lowest when thrips feeding 10%honey solution+kidney bean pod.In general,the digestive enzyme activity of F.occidentalis kept stability after 3 generations of adaptation to new foods.3.Effects of different foods on the nutrients in F.occidentalisThere were different nutrient contents at different foods.10%honey solution+kidney bean pod had the highest soluble sugar content,while rose flower had the highest amino acid content.10%honey solution+kidney bean pod and rose flower had the highest protein content.The changes in nutrients in F.occidentalis feeding on different foods were obvious at a short period of time（1,3,6,9,12,24,and 48 h）and multiple generations（F₁,F₂,F₃,F₅,F₇generations）.In most time,there was the lowest soluble sugar content in thrips adult feeding rose petal for a short time.The soluble sugar contents were not significantly different in thrips adult between feeding rose flower and 10%honey solution+kidney bean pod.Protein content was the highest in thrips feeding 10%honey solution+kidney bean pod.The contents of protein content was at the second when F.occidentalis feeding rose flower,and it was the lowest feeding the rose petal in most time.The changes of fat content were no specific pattern among feeding 3 kinds of foods.After thrips feeding multiple generations,the soluble sugar content in2nd instar nymphs and adults of F.occidentalis had the regulation of feeding 10%honey solution+kidney bean pod>feeding rose flower>feeding rose petal.The protein content of adult was the lowest in 2nd instar nymphs feeding rose petal.The protein content in adult thrips had the regulation of feeding on rose flower>10%honey solution+kidney bean pod.The fat content in 2nd instar nymphs was the highest when thrips fed rose flowers in most generations.The content in thrips adult had the follows of that feeding rose flower>10%honey solution+kidney bean pod>rose petal.There is no significant difference in the nutrient content in thrips after F.occidentalis feeding for 2 generations,which had the adaptation to different foods.