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

• Published in: Environmental entomology 2007-08, Vol.36 (4), p.887-893
• Main Authors: Luna, María G, Sánchez, Norma E, Pereyra, Patricia C
• Format: Article
• Language: English
• Subjects: Animals; BEHAVIOR; Biological and medical sciences; Biological control; biological control agents; Braconidae; Control; fecundity; Female; functional response; Fundamental and applied biological sciences. Psychology; host density; Host-Parasite Interactions; host-parasite relationships; host–parasitoid interaction; Hymenoptera - physiology; insect development; insect reproduction; Larva - parasitology; Life Cycle Stages; life history; longevity; Male; Moths - parasitology; parasitism; parasitoids; Pest Control, Biological; Phytopathology. Animal pests. Plant and forest protection; Protozoa. Invertebrates; Pseudapanteles dignus; sex ratio; Tuta absoluta
• ISSN: 0046-225X; 1938-2936
• DOI: 10.1603/0046-225X%282007%2936%5B887%3APOTALG%5D2.0.CO%3B2

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 h. 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. P. dignus females attacked hosts daily, exhibiting modest lifetime fecundity (≈32 parasitized hosts per female) and a female-biased offspring sex ratio. Female adult life span was 36 d. P. 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 six hosts per day and seemed not to be egg-limited. Percent parasitism was ≈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.