Life history of Pterostichus melanarius (Coleoptera: Carabidae) and its importance for biological control in field crops

Open Access
Author:
Busch, Anna Katherine
Graduate Program:
Entomology
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
June 03, 2016
Committee Members:
  • John Frazier Tooker, Thesis Advisor
  • Heather D Karsten, Committee Member
  • Mary Ellen Barbercheck, Committee Member
Keywords:
  • Carabidae
  • Pterostichus melanarius
  • slugs
  • Deroceras reticulatum
  • conservation tillage
  • no-till
  • non-consumptive effects
  • biological control
Abstract:
Pterostichus melanarius (Coleoptera: Carabidae) is a Palearctic generalist predator native to Europe that was introduced to North America in the 1920’s and has since become widespread in the United States. This beetle is non-native to the U.S., yet appears to have little to no negative effect on native carabids and is a critical natural enemy in agricultural systems, especially because it feeds on the invasive gray garden slug Deroceras reticulatum. My thesis begins with a review that compiles in one publication the details of P. melanarius distribution, life history, diet, and factors that influence its populations. I used ecological niche modeling to determine the current potential range of P. melanarius in the United States and found that annual mean temperature and precipitation of the driest month were the most important factors to determine probable habitat suitability. My second chapter investigates the effects of crop rotation and integrated pest management on pests and natural enemies in no-till cropping systems in central Pennsylvania. Overall, I found that diversified rotations that implemented continuous crop cover with perennial forages and cover crops and incorporated IPM enhanced the abundance of natural enemies early in the growing season and can suppress pests to similar levels attained by simple rotations managed with Bt hybrids, pesticidal seed treatments, and prophylactic pesticide application. I also found that protecting and increasing carabid abundance, especially P. melanarius, is important for slug control and can be achieved by reducing tillage, increasing crop species diversity, and using integrated pest management. Lastly, I examined the predator-prey relationship between ground beetles and slugs by investigating non-consumptive effects of P. melanarius on D. reticulatum behavior and physiology. I found that combined physical and chemical cues of P. melanarius induced fear behavior in D. reticulatum that resulted in increased hiding and decreased foraging by D. reticulatum. Due to the ineffectiveness of radioimmunoassays, I could not determine a physiological fear response. Nevertheless, there appear to be non-consumptive effects, which suggest that the pest management value of ground beetle predators such as Pterostichus melanarius may be underestimated in agricultural systems.