Demographic analysis of the immature stages of the parasitoid Diachasmimorpha longicaudata under mass rearing conditions

Resumen

Objective: To analyze the mortality of the immature stages of the parasitoid D. longicaudata using demographic parameters from a life table. 

Design/methodology/approach: Evaluations were carried out with three cohorts, each with a different level of superparasitism: puparia from 1 to 5, 6 to 10, and 11 to 15 scars (oviposition or attempted oviposition). The analysis of data was performed by life table parameters.

Results: Mortality was very noticeable in the egg stage and the first larval stage. Mortality was higher in hosts with high levels of superparasitism. After the second stage, mortality was reduced. The parameters of mortality in one day in proportion to the number of the cohort (dx) and mortality per day (qx), had their highest values between the 3rd and 4th of parasitoid development. Life expectancy at baseline was 7, 5.3 and 4.9 days at the three corresponding levels of superparasitism. After the second instar, life expectancy increased, with a steady drop until the 15th day of development. The highest emergence of adults was obtained at the average level of superparasitism (58.33%) and the lowest when the levels of superparasitism were higher (44.66%).

Limitations on study/implications:

Findings/conclusions: Intraspecific competition, host mortality due to trauma and possibly infections can be considered as the main causes of mortality in immature stages in proportions that may explain the emergence percentages obtained in mass rearing.