Parasitism of Tuta absoluta (Lepidoptera, Gelechiidae) by Pseudapanteles dignus (Hymenoptera, Braconidae) under Laboratory Conditions.

LUNA, MARÍA G.; SÁNCHEZ, NORMA E.; PEREYRA, PATRICIA C.

ENVIRONMENTAL ENTOMOLOGY

Entomological Society of America

Año: 2006

0046-225X

Laboratory studies were conducted to determine some life history traits and the functional response of the parasitoid Pseudapanteles dignus (Muesebeck), a major enemy of Tuta absoluta (Meyrick) in tomato crops in South America. Newly mated P. dignus females were individually exposed to 10 host larvae installed in mines, over a 24-h period. We determined developmental time from egg to pupa and pupal duration, mated parasitoid adult female life span, fecundity, reproductive period, daily parasitism rate, and offspring sex ratio. For functional response, treatments consisted of six host densities: 3, 5, 7, 10, 15, 20 and 30 larvae. The number and proportion of parasitized hosts were calculated for each density and the shape of the functional response curve was analyzed by means of logistic regressions. P. dignus females attacked hosts daily, exhibiting modest lifetime fecundity and a female-biased offspring sex ratio. Female life span lasted 36 days. The functional response curve fitted a type I. The mean number of parasitized hosts increased linearly with host density. Females detect and parasitize the host, within a wide range of densities, including low densities. The mean number of parasitized host reached an asymptote at a mean density of nearly six hosts per day, and the maximum number of parasitized host in a 24 h period was 14. P. dignus percentage of parasitism in the present study was about 30%. Ecological implicances of the results in relation to the potential of P. dignus for the biological control of T. absoluta in tomato are discussed. Keywords: Pseudapanteles dignus, Tuta absoluta, host-parasitoid interaction, functional response, biological control.