Efecto de la planta hospedera (Brócoli, col, rábano), sobre el polimorfismo de Plutella. xylostella BBC ambatense bajo condiciones de laboratorio

Abstract

The present investigation proposes to know if the polymorphism from larvae of population af Plutella xylostella BBC ambatense is explained by the feeding on the host plant in which it is bred, five individuals with good development were photographed in their fourth instar randomly selected from the population of P. xylostella BBC ambatence. The photographs were digitally analyzed with a code developed on "R" software which allowed extracting RGB pixel intensity (RED GREEN BLUE) from images. The obtained data were analyzed with non-parametric analysis of conglomerates and variance. It was observed from the population at P. xylostella BBC ambatence, three polymorphisms intensity of green color, dark tones (brown) and light tones (yellowish). This polymorphism was determined by host plant with which the larva was fed, not by inheritance of the parental phenotype of their parents. In a conglomerate analysis for color, two groups were identified; larvae that were fed with Brassica oleracea var. capitata and larvae that were fed with Brassica oleracea var. italica and Raphanus raphanistrum subsp. sativus The dark colored larvae were less resistant to the chemical insecticide Chlorpyrifos, than the green colored larvae. It was observed that the larvae fed with Brassica oleracea var. Itálica had a larger size compared with the larvae fed with Brassica oleracea var. capitata and Raphanus raphanistrum subsp. sativus . In oder to explain these results, it is hypothesized: 1. that t color polymorphism of P. xylostella larva BBC ambatence is a cryptic capacity to color of the host plant. 2. That this cryptic capacity is related to avoiding predation and parasitism. In addition, 3. This critical capacity of larvae from P. xylostella BBC ambatence present fitness cost for the resistance chemical insecticide chlorpyrifos. Keywords: POLIMORFISM, LARVAS PLAGA, COST OF ADAPTATION, HOSPEDERA PLANT, CRIPTIC CAPACITY.