Date of Award

Spring 2018

Document Type

Honors Thesis



First Advisor

Dr. Meghann Jarchow

Second Advisor

Dr. Robert Bagchi

Third Advisor

Dr. Leone Brown


Invasive species, fragmentation, Lymantria dispar, gypsy moth


Lymantria dispar(Gypsy moths) are an invasive species inNorth America thatdevastate forestsbycausingmass defoliation. WhileL. disparpopulations persist eachyearin an expanding range, defoliation eventsare most extremeduring outbreak years.Two non-native pathogensare known to help controlL. disparpopulationsin NorthAmerica:the fungusEntomophaga maimaiga,and virusLymantria disparnucleopolyhedrovirus(LdNPV).Both pathogens and their hostL. disparare found intheheavily fragmented forests ofeasternConnecticut, wherethis study was conducted.Because forestfragmentsof different sizes vary in microclimate and other attributes,controlofL. disparby these pathogens may also vary.For instance, as a fungus,Entomophagamay be more likely to spread in larger forest fragmentsthathave highermoisture and vegetation density than smaller fragments.LdNVP spreads at a higher ratewith increased populationdensity,butthe relationship betweenL. disparpopulationdensity and forest fragment size is not documented.I reareda sample of fifteenindividuals ofL. disparfromeach ofthirty-two forest fragmentsandfoundthat mortalityfrombothEntomophagaandLdNPVis higherin large forest fragmentsthansmallfragments(Χ2= 12.64,df= 1,p< 0.0004). Thissuggests thatforestconditions that varywith fragment size may influence pathogen spreadandinhibit control ofL.disparbythese pathogens.



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