Parasitism of T. absoluta by P. dignus (Luna et al, 2007)Submitted by Lunam on 28th Apr 2010
Environ. Entomol. 36(4): 887-893 (2007) ABSTRACT Laboratory studies were conducted to measure selected life history traits and thefunctional response of the parasitoid Pseudapanteles dignus (Muesebeck), a major enemy of Tutaabsoluta (Meyrick) in tomato crops in South America. Newly mated P. dignus females were individuallyexposed to 10 host larvae in mines for 24 h.Wedetermined 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 parasitizedhosts 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.Weobserved thatfemales 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 inrelation to the potential of P. dignus for the biological control of T. absoluta in tomato are discussed.