Theses and Dissertations

Date of Award

7-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Dr. Rupesh Kariyat

Second Advisor

Dr. Bradley Christoffersen

Third Advisor

Dr. Nirakar Sahoo

Abstract

Pollination and herbivory are two major interactions in insect-plant ecology. Specialized pollination systems such as buzz pollination where pollen grains have to be extracted by bees with special thoracic vibrations and indirect flight muscles, is observed in ~6% of all flowering plants. Breeding and research programs in these species demand artificial pollination, but natural buzz pollinators are unreliable for this purpose. To find an alternative, we tested the pollen extraction efficiency of using inexpensive electric toothbrush over tuning fork (another commonly used device) in two buzz-pollinated species (Tomato and Silverleaf nightshade) at different buzzing frequencies and multiple buzzing time intervals. Our results show that species and extraction time significantly influenced pollen extraction, while there were no significant differences for the different vibration frequencies and more importantly, the use of a toothbrush over tuning fork. We conclude that electric toothbrushes can be used as a viable and inexpensive alternative to tuning forks for pollen extraction. As the second most important insect mediated species interaction, herbivory, is one of the major threats in crop production and food security. Although synthetic chemicals and pesticides are used to manage insect-pests, their use have led to major concerns of resistance development, pest resurgence as well as toxicity to non-target organisms. Plant-based bioactive compounds are good alternatives, but their use is limited by complicated and expensive extraction and purification methods. We tested the effects of polyphenol rich purple corn pericarp extract (extracted inexpensively) on the growth and development of Manduca sexta, a damaging herbivore. We found that pericarp extract negatively affects egg hatching, mass gain, developmental time and these effects cascade through pupal, adult and next generation offspring suggesting its potential suitability as a biopesticide. Taken together, our findings of inexpensive pollen extraction and sustainable pest management methods can have implications in improving agricultural practices.

Comments

Copyright 2020 Mandeep Tayal. All Rights Reserved.

https://go.openathens.net/redirector/utrgv.edu?url=https://www.proquest.com/dissertations-theses/insect-mediated-species-interactions-examining/docview/2454639502/se-2?accountid=7119

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