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Document Type

Thesis - University Access Only

Award Date

2012

Degree Name

Master of Science (MS)

Department

Plant Science

First Advisor

Louis Hesler

Abstract

Of roughly 450 species of native North American coccinellids (Coleoptera: Coccinellidae), at least three have dramatically declined in recent decades. The three species have been found recently in western South Dakota and western Nebraska, but their habitat _associations there are poorly understood. The objectives of this research were to identify whether extant populations of declining species still exist in southwestern South Dakota and northwestern Nebraska, and if so, to what extent are they present, which land-use types are they present within, and where are they reproducing. In addition to declining species, this study tested four sampling techniques (yellow sticky traps + sucrose, yellow sticky traps, sweepnetting, and visual searches) across three land-use types (pasture, alfalfa, and small grain) at four locations in western South Dakota and Nebraska from late May to early August 2010 and 2011 in hopes of characterizing resource use and sampling efficiency for all sampled coccinellids. Opportunistic visual searches for coccinellids among roadside vegetation supplemented systematic sampling at each site. Adults and larvae of the ninespotted lady beetle (Coccinella novemnotata Herbst), one of the declining species, were found in alfalfa and pasture in 2010, and composed 0.11 % of all coccinellids sampled. In 2011, the ninespotted lady beetle was found in all three habitats and composed 2.75% of all coccinellids sampled. The other two species in decline were never found at any location either year. Regarding all species, most coccinellid adults-and larvae were captured in small grain fields, intermediate numbers were found in alfalfa, and fewest were captured in pasture. Two yellow sticky trap methods captured the most adult coccinellids. Sweepnetting was more effective than visual searches and consistently less effective than sticky traps for sampling adults but rivaled sticky traps when larvae were included. In 2010 and 2011, a total of 30 Coccinella novemnotata and 14 Coccinella transversoguttata richardsoni Brown adults, two species of conservation concern, were observed in roadside vegetation. Continued surveillance of declining and stable native populations and increasing adventive populations is essential for comprehending shifts that are occurring within these coccinellid communities in western South Dakota and western Nebraska.

Library of Congress Subject Headings

Coccinella -- South Dakota Coccinella -- Nebraska Ladybugs

Format

application/pdf

Number of Pages

99

Publisher

South Dakota State University

Rights

In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/

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