Discipline: Biological Sciences
Yumary Vasquez - California State University San Marcos
Co-Author(s): Hannah Vansant, California State University San Marcos, CA; Arun Sethuraman, California State University San Marcos, CA
Dinocampus coccinellae (Hymenoptera:Braconidae) is a parasitoid wasp that affects more than 40 species of predatory lady beetles (Coleoptera:Coccinellidae). Braconid wasps tend to be highly host-specific, which brings into question the potential diversification due to host-specific adaptations of D. coccinellae and its origins and evolutionary history have never been studied. Coccinellidae are commonly utilized as natural enemies in augmentative biocontrol in the United States. With host survival rates of less than 25% following parasitization by D. coccinellae, the increasing co-occurrence of wasps and their host is predicted to have implications on both the ecosystem as well as the biocontrol industry. This study attempts to delineate diversity and differentiation at the morphological and genomic levels in populations of field collected D. coccinellae, parasitizing 6 different species of Coccinellidae. Specifically, we are interested in (a) potentially plastic or adaptive evolutionary trait variation of wasp morphology in response to the size of its host, and (b) quantifying the phylogenomic diversity of D. coccinellae to identify potential sub-species. 40 parasitoid wasps and their hosts were field-collected in the states of Kentucky, Illinois, New York, Arizona and Kansas and shipped for analyses to our lab. Wasps and hosts were stored in 95% ethanol at -20℃ once the wasp eclosed from pupation. Specimens were photographed in two separate rounds and weights of wasps and host were recorded separately on an analytical balance after air-drying the ethanol for 2 minutes. Several morphological characteristics (of both wasps and hosts) were recorded in millimeters using ImageJ software. Preliminary results indicate significance (P value < 0.05) and a positive correlation (R2 = 0.181) between the parasitoid weight and their host weight. This is suggestive of parasitoid size being a plastic trait, which could be due to a number of factors including food availability and life-history stage of the host. One-way Analysis of variance (ANOVA), testing the null hypothesis that there is no variation in means of measured morphological variables in the wasp between their corresponding host species indicates significant (P < 0.05) differences only in abdominal lengths. All other variables were not significant (P > 0.05).These results indicate the need for further analysis for these parasitoid wasps beyond morphological differences, specifically through genomic analyses. Continuing research involves whole genome sequencing of D. coccinellae to determine signatures of adaptive evolution involved in host-switching and host-specificity, as well as quantifying their recent phylogenomic history in the United States. References: Obrycki, John J. “Parasitization of Native and Exotic Coccinellids by Dinocampus Coccinellae (Schrank) (Hymenoptera: Braconidae).” 1989 Strand, Michael R., and John J. Obrycki. “Host Specificity of Insect Parasitoids and Predators.” 1996Abstract.pdf
Funder Acknowledgement(s): This work was supported by a GPSM grant from the Office of Graduate Studies and Research at CSUSM to Arun Sethuraman The San Diego Foundation
Faculty Advisor: Arun Sethuraman, email@example.com
Role: I recorded the wasp and host weight as well as assist in taking the images for each round. I created the macro shortcuts used in ImageJ for the measurement of the morphological variable. I calculated the statistics in this research and created the graphs using R studio. I have primarily been working on extracted the DNA from the wasp and preparing them for whole genome sequencing.