Cascading effects of polyphenol-rich purple corn pericarp extract on pupal, adult, and offspring of tobacco hornworm (Manduca sexta L.)

ABSTRACT

A major bottleneck in the commercialization of plant-based pest management compounds is that the extraction methods are complex, time-consuming, and even highly expensive. Using a recently developed inexpensive extraction and quantification methodology to isolate polyphenols (including anthocyanins and condensed tannins) from purple corn pericarp, we examined their effects on Manduca sexta, a common insect herbivore. Following up on our previous work which demonstrated the negative impacts of polyphenol-rich extract on larval stages, we further examined whether there are any cascading effects on subsequent life stages (pupal and adult) including any possible transgenerational effects. Our results show that polyphenol-rich purple corn extract-fed caterpillars had significantly lower pupal mass and survival. Moreover, adult moths also had lower mass when eclosed from caterpillars reared on the extract diet. To test whether there were any transgenerational effects, we allowed male and female adults fed on purple corn extract diet and control diet to mate and lay eggs in a full factorial experiment. We found that purple corn extract-fed adult pair laid a lower number of eggs compared to other treatments. In addition, we also found that second instar M. sexta caterpillars hatched from eggs laid by any mating combination with at least one parent reared on purple corn extract gained significantly lower mass compared to caterpillars with both parents reared on the control diet. Taken together, our results show that there are cascading negative effects for feeding purple corn pericarp extract on pupal, adult, and second generation of M. sexta, reaffirming its potential application as a cost-effective and environmentally friendly pest deterrent.

KEYWORDS:

• Tobacco hornworm
• polyphenols
• purple corn
• herbivore
• growth and development
• pupal mass

Acknowledgments

We kindly acknowledge Dr. Bradley Christoffersen for reviewing and providing valuable comments throughout the manuscript. We are also thankful to Priscilla Trujillo, Karliza Garza, Sukhman Singh, and Andrea Roman for their assistance in data collection.

Authors’ contributions

MT, PS, and RK designed the study. MT, IR, and LM carried out experiments and data collection. RK and MT analyzed the data. MT and RK wrote the manuscript and all authors contributed with edits and revisions.

Disclosure statement

The authors declare no competing interests.

Consent for publication

All authors agree to the publication.

Availability of data and material

Data is available online in the Dropbox (https://www.dropbox.com/s/lorty5vyvt5h9sj/CIB%20Data%202020.xlsx?dl=0).

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

The project was funded by the following grants awarded to Dr. Rupesh Kariyat: UTRGV Transforming the world-Strategic plan award, UT system Rising Star Award, and Startup funds; UTRGV Transforming the world-Strategic plan award [NA]; UT Rising Star Award [NA].