Tachinid Fly (Lespesia archippivora) Parasitism of Monarch Butterfly Larvae (Danaus plexippus) Kaitlyn Creasey February 14, 2007

University of Minnesota Dr. Karen Oberhauser

Tachinid Fly (Lespesia archippivora) Photo by Author

Armyworm

Monarch Butterfly Larva (Danaus plexippus) Photo by Author

Life Cycle of Tachinid Flies Photos by Author and Dr. Karen Oberhauser

Life Cycle of Tachinid Flies Photos by Author and Dr. Karen Oberhauser

Life Cycle of Tachinid Flies Photos by Author and Dr. Karen Oberhauser

Life Cycle of Tachinid Flies Photos by Author and Dr. Karen Oberhauser

Life Cycle of Tachinid Flies Photos by Author and Dr. Karen Oberhauser

Life Cycle of Tachinid Flies Photos by Author and Dr. Karen Oberhauser

Monarch Instars Photo used with permission of Dr. Karen Oberhauser

Egg Photo used with permission of Dr. Karen Oberhauser

First-instar Photo used with permission of Dr. Karen Oberhauser

Second-instar Photo used with permission of Dr. Karen Oberhauser

Third-instar Photo used with permission of Dr. Karen Oberhauser

Fourth-instar Photo used with permission of Dr. Karen Oberhauser

Fifth-instar Photo used with permission of Dr. Karen Oberhauser

Focus of Project Continue Oberhauser study ( ) on wild monarch tachinid parasitism Study correlations of sex, mass, and length of pupation of tachinid pupae Successfully parasitize monarch larvae with laboratory-raised tachinid flies

Photo by Author

Background Goal 2: Find correlation between tachinid pupae sex, mass, and duration of pupal stage of tachinid flies Cardoza et al. (1997)

Hypotheses Female tachinid pupae would be larger than male tachinid pupae and duration of pupal stage would be longer for females Number of tachinid larvae laid on a monarch larva would affect the mass of tachinid pupae

Solutions for Problems Encountered After 24 hours, monarch larvae had died before any tachinid larvae could emerge

Solutions for Problems Encountered After 24 hours, monarch larvae had died before any tachinid larvae could emerge Echegaray (1975)

Solutions for Problems Encountered After 24 hours, monarch larvae had died before any tachinid larvae could emerge Echegaray (1975) Dissection showed an average of 20 tachinid fly larvae in a single dead monarch larvae

Superparasitized Monarch Larva

Solutions for Problems Encountered Larvae exposure time to the flies was shortened in order to avoid super parasitism and allow tachinid larvae to fully develop

Tachinid Fly Parasitized Wild Monarch Larvae Survey Percent healthy adults Percent parasitized by tachinid flies Percent died from other causes 70.9 (n=61)7.0 (n=6)22.1 (n=19)

Tachinid Fly Parasitized Wild Monarch Larvae Survey Percent healthy adults Percent parasitized by tachinid flies Percent died from other causes 70.9 (n=61)7.0 (n=6)22.1 (n=19)

Percent Parasitized Monarch Larvae at each Site

Percent Monarch Larvae vs. Instar at Collection (chi square value=11.296, df=6, 0.10>p>0.05)

Mean Tachinid Pupa Mass vs. Sex (p=0.0001; standard error for females =9.31 x ; standard error for males =1.97 x )

Tachinid Sex vs. Tachinid Duration of Pupal Stage (p=0.0001; standard error for females =0.31; standard error for males =0.18)

Number of Tachinid Larvae per Monarch Larva

Number of Tachinid Larvae per Monarch Larvae vs. Mean Tachinid Pupae Mass (p=4.29E-4, standard error for 1-4 = 3.77E-5; standard error for 5-8 = 1.60E-5)

Monarch Parasitisms by Tachinid Flies Monarch instarNumber of tachinid larvae First2 Fourth3

Conclusion 7% wild monarch larvae parasitized

Conclusion 7% wild monarch larvae parasitized Male tachinid pupae were statistically heavier than females and remained in the pupal stage longer than females

Conclusion 7% wild monarch larvae parasitized Male tachinid pupae were statistically heavier than females and remained in the pupal stage longer than females When a larger number of tachinid larvae emerged from host monarch larvae, the average mass of the tachinid pupae was significantly less

Future Work Continuing the study of percent of parasitized monarch larvae

Future Work Continuing the study of percent of parasitized monarch larvae Maintaining a population of tachinid flies in the laboratory

Future Work Continuing the study of percent of parasitized monarch larvae Maintaining a population of tachinid flies in the laboratory Continuing the study of the relationships between tachinid flies and monarch larvae

Acknowledgements Dr. Karen Oberhauser Roger Moon Lois Fruen Research Class

Tachinid Fly (Lespesia archippivora) Parasitism of Monarch Butterfly Larvae (Danaus plexippus) Kaitlyn Creasey February 14, 2007