Survival and fecundity of single and grouped clonal sorghum aphids and a novel aphid marking technique

Authors: CAREY, CAMILLE - OKLAHOMA STATE UNIVERSITY; HOBACK, WYATT - OKLAHOMA STATE UNIVERSITY; ARMSTRONG, JOHN; HAYASHIDA, RAFAEL - OKLAHOMA STATE UNIVERSITY; ZARRABI, ALI - OKLAHOMA STATE UNIVERSITY

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2023
Publication Date: 7/14/2023
Citation: Carey, C., Hoback, W., Armstrong, J.S., Hayashida, R., Zarrabi, A. 2023. Survival and fecundity of single and grouped clonal sorghum aphids and a novel aphid marking technique. Southwestern Entomologist. 48(2):303-311. https://doi.org/10.3958/059.048.0202.
DOI: https://doi.org/10.3958/059.048.0202

Interpretive Summary: Aphids species have one of the highest reproductive capacities of all insects. Life history characterizations of aphids such as reproductive measurements are used in determining host-plant resistance traits in the development of resistant crops. We compared life history and reproduction capacity of a single sorghum aphid clone with life history parameters of groups of 10 females on susceptible sorghum. Some literature comparing single versus groups of reproducing females provided information that slightly favored a higher reproductive rate for groups over single aphid reproduction. Our replicated experiment showed there was no difference in the reproductive rate of single sorghum aphids versus groups of ten. We investigated using non-toxic permanent markers (black, blue, green and red) by marking aphids with colored dots on each individual to identify which clan they belonged to. Survival and reproduction of marked individuals was similar to controls and marks were readable for at least two weeks, demonstrating that permanent markers can be used when an experiment requires following individuals or cohorts that are mixed. “The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at [phone] (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, or call [phone] (voice) or [phone] (TDD). USDA is an equal opportunity provider and employer.”

Technical Abstract: Aphids have high intrinsic rates of increase because clonal females can reproduce parthenogenetically. Studies to investigate host-plant resistance often measure life history characteristics of an individual on the test cultivar. However, aphid lifespan, fecundity, and intrinsic rate of increase could be influenced by the presence and feeding effects of multiple individuals, potentially overestimating antibiosis when a single individual is monitored. We compared life history traits of a single sorghum aphid, Melanaphis sorghi, with life history parameters of groups of 10 females on susceptible sorghum. There were no significant differences between the single and grouped aphids for longevity (P= 0.08; F= 3.67), the number of offspring produced (P=0.59, F =0.31), the time spent in reproduction (P= 0.08; F= 3.74) or the number of offspring per day (P=0.35, F=0.93). Demographics parameters (fecundity rate (Dm) and intrinsic rate of increase (rm) were also not different. Overall, our results indicate that single aphids are suitable to investigate host plant resistance, including antibiosis. When investigations require using groups of aphids, it can be difficult to identify individuals. We investigated using non-toxic permanent markers (black, blue, green and red) to place colored dots on individuals. Survival and reproduction of marked individuals was similar to controls and marks were readable for at least two weeks, demonstrating that permanent markers can be used when an experiment requires following individuals or cohorts that are mixed. USDA is an equal opportunity provider and employer.