The Mode Of Reproductive And The Development Characteristics Of Ovarian Of Cotton Mealybug Phenacoccus Solenopsis Tinsley

Phenacoccus solenopsis was found a pest which invaded our country in recent years.This pest is great potential dangerous to our country agricultural product,and threat safety production of many ornamental plants and economic crops,especialy cotton safety production.P.solenopsis possess high reproducibility and there are controversy in the mode of reproduction of mealybug.Most studies suggest that cotton mealybug can produce offspring by both parthenogenesis and bisexual by ecological observation.Other studies indicate that it can only be bisexual and cannot produce offspring by parthenogenesis.We studies the mode of reproduction of mealybug through ecological observation and anatomical observation under the microscope,and are described the growth dynamic of its ovarian under mated、delayed mating and unmated.Results are as follows:The parthenogenetic treatment of P.solenopsis was carried out by ecological observation:For 5 consecutive generations of parthenogenetic treatment of P.solenopsis were bom to produce offspring,we found that mealybug can produce both female and male offsprings.So the mode of reproduction of P.solenopsis is facultative deuterotoky.The number of preoviposition,fecundity,number of offspring females and offspring males were compared between the offspring of each generation.The results showed that the first generation,and the second generation are only one female produce offspring,the third generation of 3,the fourth generation of 11,the fifth generation of 5 female;the preoviposition were 10 d,9 d,13.3±1.5 d,16.1±1.2 d,13.6±2.0 d,respectively;fecundity were 407 eggs,587,364.3±91.9,342.8±54.8,339.0±23.4,respectively;the number of offspring females were 229,298,189.7±40.2,166.1 ±26.9,182.2±25.4,respectively;the number of offspring males were 178,289,174.7±54.6,167.9±25.6,155.8±10.5,respectively.There are no significant difference among preoviposition,fecundity,number of offspring females and offspring males,so each generation of parthenogenetic parents has a stable reproductive capacity.P.solenopsis female adults are dissected,microscopic observation showed that the reproductive system femaleP.solenopsis consists of a pair of ovaries,a pair of lateral oviduct,a common oviduct,a pair of accessory gland and a spermatheca.Each ovary was composed of hundreds of terminal telotrophic ovarioles.Mated female P.solenopsis adults that matured 1-30 day are dissected.According to the developmental degree of eggs female P.solenopsis adult ovaries,the ovaries of P.solenopsis were divided into three stages:early developing stage,developmental stage,late development stage.At the early development stage,the female ovaries were wrapped by immature oocytes which was not egg yolk accumulation.Eggs are oval and egg yolk is rapidly accumulating after fertilization,and the number increased rapidly.There were hundreds of embryos in the ovaries with different stages of development.Accompanied by the head,chest,abdominal differentiation at the developmental stage.Differentiation of complete embryos away from the maternal,undifferentiated complete embryo continue to divide,the entire developmental stage lasted 30 days.There were no or very litter oocytes in the ovaries at the late development stage.Delayed mating 15 day female P.solenopsis adults that matured 1-30 day are dissected.According to the developmental degree of eggs female P.solenopsis adult ovaries,the ovaries of P.solenopsis were divided into three stages:early developing stage,developmental stage,late development stage.In the whole early developing stage,each eggs in the ovaries had a globular trophoblast cells at the top of the egg to the ovaries where trophoblast cells are absorbed by oocytes.And the last the embryo within eggs finish the head,chest,and abdomen of the complete differentiation process.Differentiation of complete embryos in the developmental stage away from the maternal,undifferentiated complete embryo continue to divide,the entire spawning period lasted 18 days.There were no or very litter oocytes in the ovaries at the developmental stage.Unmated female P.solenopsis adults that matured 1-30 day are dissected.Its ovary length and adult development days,there was no significant linear relationship.According to the developmental degree of oocytes female P.solenopsis adult ovaries,the ovaries of P.solenopsis were divided into four stages:early developing stage,developmental stage,late development stage and apoptotic stage.The oocytes of theearly development of the ovaries were immature,and the shape of tears like no yolk deposition;the yolk of the developmental oocytes was gradually accumulate,and spherical and transparent nurse cell were appeared up on top of the developmental oocytes,in the development of the number of oocytes increased;late development of oocytes continue to develop,but spherical nurse cell seemed to be in the stagnation stages of development;the number of apoptotic oocytes began to decline,the ovaries began to shrink,there is only a small amount of oocytes in the ovaries.