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

LUNA, M.G.; SANCHEZ, N.E.; PEREYRA, P.C.

ENVIRONMENTAL ENTOMOLOGY

Entomological Society of America

Año: 2007 vol. 36 p. 887 - 893

0046-225X

Laboratory studies were conducted to measure selected 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 in mines for 24 hours. We determined developmental time from egg to pupal formation and pupal stage duration, female adult life span, fecundity, reproductive period, daily parasitism rate, and sex ratio of offspring. For the functional response experiment, treatments consisted of six host densities: 3, 5, 7, 10, 15, 20 or 30 larvae. The number and proportion of parasitized hosts were calculated for each density. The shape of the functional response curve was analyzed by logistic regression. Pseudapanteles dignus females attacked hosts daily, exhibiting modest lifetime fecundity (ca. 32 parasitized hosts per female) and a female-biased offspring sex ratio. Female adult life span was 36 days. Pseudapanteles dignus showed a Type I functional response within the range of host densities tested. We observed that females detect and parasitize the host within a wide range of densities, including low densities. The functional response curve reached an asymptote at a mean density of 6 hosts per day and seemed not to be egg-limited. Percent parasitism was about 30%. The ecological implications of the results in relation to the potential of P. dignus for the biological control of T. absoluta in tomato are discussed.