<p>  </p> <p>Invasive species are a prominent problem throughout the world due to the high economic and ecological impact they have on environments. The spongy moth, <em>Lymantria dispar</em>, is a well-known and intensely studied invasive species within the United States because of the high environmental (<em>e.g.</em>, defoliation) and economic (<em>e.g.</em>, management efforts) costs. Originally introduced in Massachusetts in 1869 their range now covers much of the Northeast and Midwest, with the potential to disperse much further. </p> <p><br></p> <p>The goal of this study is to determine how the landscape has influenced <em>L. dispar</em>’s invasion rate through least-cost resistance modeling. Resistance modeling is a technique that combines the biology of <em>L. dispar </em>and landscape connectivity to potentially explain the invasion rate. Landscape connectivity has varying effects on invasion dynamics depending on the spatial scale. Monitoring efforts for <em>L. dispar</em> have occurred at a small spatial scale throughout the entire range for many years, which now provides the opportunity to look at invasion dynamics at small spatial scales. Identifying the landscape’s influence on invasion dynamics at these scales can assist in targeting management efforts to areas that have a high likelihood of being invaded soon based on the landscape connectivity within the area. This targeted management strategy can potentially help to slow <em>L. dispar</em>’s establishment and dispersal ability and reduce management and monitoring costs.</p>

The Geometrinae, commonly known as emerald moths, are a diverse group of Lepidoptera with over 450 Neotropical species. However, Caribbean Geometrinae have received relatively little attention compared to the Geometrinae of mainland Central and South America. Using the method of Lee and Brown (2006), whole body mounts of descaled specimens of both Caribbean and mainland Neotropical Geometrinae were prepared. Morphological variation of exo- and endoskeletal characters among species, genera, and tribes of Neotropical Geometrinae is described. A faunistic study of Caribbean Geometrinae was also conducted using material from museums and private collections. The study includes definitions of species of Caribbean Geometrinae, descriptions of new species, and illustrations of adult imagos, genitalia, and other external characters. A key to the species of Caribbean Geometrinae is also provided.

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Field studies were conducted to evaluate the effect of mating disruption on the mating success of the gypsy moth, Lymantria dispar (L), in low-density populations. The gypsy moth is an insect pest of hardwood forests in many regions of the world. The discovery of the sex pheromone disparlure (cis-7,8-epoxy-2-methyloctadecane) produced by females marked the start of a new era in the control and management of gypsy moth populations. Sex pheromones, like disparlure, have been used for detecting new populations, monitoring the spread of populations and for population control based on the disruption of mating communication. Although mating disruption has been used against populations of insect pests in agricultural and forest systems, considerable information about the use of this method for managing gypsy moths is still lacking. Studies, therefore, were designed and carried out specifically to improve current understanding of the mechanism of mating success, to evaluate existing techniques for mating disruption, and to develop methods that would improve the application of pheromone used for mating disruption so as to reduce the costs associated with the use of this management tactic. The first study was conducted to compare the mating success and mortality of gypsy moth females in low-density populations in Virginia and Wisconsin because of differences, which have been observed in the population dynamics and the impact of management strategies between these two states. The results suggested that the higher rate of population spread in Wisconsin might be due to the increased mating success of females compared with Virginia, which may be due in part to increased long-distance dispersal of males and increased longevity of females. The effect of artificial pheromone applied at various doses and formulations on mating success in low-density gypsy moth populations also was studied. Dose-response relationships were obtained for pheromone doses ranging from 0.15 to 75 g a.i./ha. The doses of 37.5 and 15 g a.i./ha of pheromone were shown to effectively disrupt mating and, therefore, have been recommended for operational use. The results also showed that the disruption of mating and attraction of males to pheromone-baited traps as a result of application of pheromone formulated in plastic flakes (Disrupt® II, Hercon Environmental, Emigsville, PA) was stronger and lasted longer than for the pheromone formulated as microcapsule (3M Canada Co., London, Ontario, Canada) and in liquid (Shin-Etsu Chemical Co. Ltd, Tokyo, Japan). Another study was carried out to improve the use and efficacy of the pheromone for mating disruption by reducing the amount of pheromone that was sprayed and the flight distance during aerial application. This study showed that in mountainous landscapes the effect of disparlure along the valley between mountains could be observed at a larger distance (633 ± 63 m) from the treated area than across the valley (104 ± 22m). In a relatively flat area, the effective distance for mating disruption was similar to the effective distance across the valley in a mountainous area (67 ± 17m). These dispersal characteristics of the pheromone provided further evidence that it could be used effectively in mating disruption treatments. Finally, a portable Electroantennogram (EAG) device was evaluated for its ability to detect disparlure sprayed for mating disruption in gypsy moth populations. The study found no relationship between the dose of artificial airborne pheromone and response of gypsy moth antenna as measured by the voltage ratio. The inability to detect differences between airborne pheromone concentrations in the plots treated for mating disruption might have been due to high variability among antennae and also by the inability of the EAG device to detect the low concentration of airborne pheromone used operationally for mating disruption. Further studies are required to improve the sensitivity of the portable EAG device before it can be recommended for use in the field. / Ph. D.