Effects of host-plant density on herbivores and their parasitoids: A field experiment with a native perennial legume

Abstract

Professor Krishnaswamy Jayachandran, Major ProfessorSenna mexicana chapmanii (Fabaceae: Caesalpinoideae), an attractive and threatened species native to pine rocklands of southern Florida, is consumed by folivorous caterpillars of Sulfur butterflies (Lepidoptera: Pieridae). Caterpillars may be deterred or eaten by predators, but also very important are parasitoids, both flies and wasps. This study investigated the effects of plant density on Sulfur caterpillar numbers and rates of parasitization.Senna mexicana chapmanii plantations were established at agricultural and urban areas; both sites are adjacent to protected pine rockland areas. Sulfur butterfly immature stages were collected and reared to glean information regarding number of herbivores and rates of parasitization. Continuing this weekly monitoring protocol over the course of a year provided data to determine that higher plant density has an effect on levels of parisitization and is correlated with the number of herbivores. Elucidating these patterns has important implications understanding the factors that regulate interactions in this plant/herbivore/parasitoid system.

Weeds Enhance Pollinator Diversity and Fruit Yield in Mango

“…Further studies should clarify how field and surrounding weedy vegetation affects insect biodiversity and mango fruit yield, as well as soil abiotic and biotic functions and nutrition. Using other sources of insectary plants, such as sweet alyssum [9], or native herbs such as the Bahama Senna [63] could be an alternative for farmers to garner beneficial insects in South Florida. Additionally, farms in this area are surrounded by an increasingly urbanized landscape, and the relationship among urbanization, pollinator resource distribution, pollinator abundance, and pollination service provision are uncertain [64].…”