Spatial and temporal patterns of carabid beetle (Coleoptera: Carabidae) assemblages in winter wheat factor into their potential as biocontrol agents
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Authors
Franklin, Emily
Issue Date
2012
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
An alternative to pesticide use in agriculture is the use of natural enemies such as
predators as a pest control technique, also known as biocontrol. This technique requires
an understanding of the enemies and their interactions with the environment. In order for
a predator to be an effective biocontrol agent in agriculture it must be present throughout
the field for the entire season, especially early in the season when the first pest colonizers
appear. This study looks at the spatial and temporal abundances of carabid beetles
(Coleoptera: Carabidae) in winter wheat over a growing season to assess their potential as
biocontrol agents of grain aphids. Carabids were collected for eight weeks by pitfall
traps placed in the edges and centers of wheat fields. The total abundance of carabids
and the abundance of the three most common species of carabid beetles were analyzed as
a factor of time and location. A total of 54 carabid species were identified out of the
3,437 individual carabid beetles collected. The three most abundant carabid species were
Amara aenea, Pterostichus melanarius, and Agonum placidum in descending order. The
general carabid population inhabited the entire wheat field (center and edge) however the
population did not inhabit wheat in great abundances during the first half of the season.
Separately, each species had its own distributional pattern. A. placidum individuals were
found in the center more often than the edge. During the early season P. melanarius were
more abundant in the edge, but were more abundant in the center late in the season. A.
aenea showed a more even distribution throughout the wheat fields. All three species
peaked in the late season, however A. placidum also peaked at the beginning of the
growing season. Although each individual species would not be very effective at
controlling grain aphids alone, each species’ unique density patterns complements the
other to provide better control of pest populations. A diverse assemblage of carabid beetles has the potential for successful biocontrol especially with the addition of climbing
predators such as lady beetles and habitat modifications providing overwintering sites for
predators.
Description
v, 23 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.