Population ecology of Leptinotarsa undecimlineata Stal (Coleoptera: Chrysomelidae) and their effects on Solanum lanceolatum Cav in Honduras
Abstract
A 1.5-year study on the population ecology of Leptinotarsa undecimlineata Stal was conducted in Honduras. The objectives were to detect important mortality factors that can be evaluated for the control of the Colorado potato beetle, L. decemlineata Say and to understand the relationship of the beetle and its host plant. The research was carried out in Honduras, a country that forms part of the aboriginal home of the Leptinotarsa. Life tables of L. undecimlineata were constructed using populations of L. undecimlineata found on one of its native hosts, Solanum lanceolatum Cav (Solanales: Solanaceae). In addition, the plant-herbivore relationship was studied by subjecting the plant to different beetle pressures, which were obtained by protecting some of the plants. The species L. undecimlineata has two distinct generations per year, the largest one coinciding with the rainy season lasting from August to November. The highest mortality was found in the egg stage and was caused by predators. The most common predators observed were Lebia sp. (Coleoptera: Carabidae), Cycloneda sanguinea L. (Coleoptera: Coccinellidae) and Perillus splendidus (Uhler) (Heteroptera: Pentatomidae). The pupal stage also had significant mortality, which was caused by a complex of parasitoids belonging to the genus Myiopharus. (Diptera: Tachinidae). The study revealed that L. undecimlineata is the most important defoliator of S. lanceolatum. Most of the protected plants were able to grow and reproduce. A large number of plants not protected suffered high defoliation rates and were in general, not able to produce flowers and fruits. This study has shown there is a significant influence of natural enemies on L. undecimlineata populations, particularly from predators. New species have been identified and could potentially become part of the arsenal used against the Colorado potato beetle. The study has also shown L. undecimlineata exerts significant defoliation pressures on S. lanceolatum and is probably an important agent of selection. Further refinement of our understanding of S. lanceolatum-L. undecimlineata interactions awaits additional study of their co-evolutionary dynamics and meta-population ecology.
Degree
Ph.D.
Advisors
O'Neil, Purdue University.
Subject Area
Entomology|Ecology|Agriculture
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