Effects of Diaphorina citri population density on daily timing of vibrational communication calls: Potential benefits in finding forage

Authors: Mankin, Richard; PATEL, RIKEN - University Of Virginia; GRUGNALE, MASON - Former ARS Employee; JETTER, ETHAN - University Of Florida

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2020
Publication Date: 3/13/2020
Citation: Mankin, R.W., Patel, R., Grugnale, M., Jetter, E. 2020. Effects of Diaphorina citri population density on daily timing of vibrational communication calls: Potential benefits in finding forage. Insects. 11(3):182. https://doi.org/10.3390/insects11030182.
DOI: https://doi.org/10.3390/insects11030182

Interpretive Summary: The Asian citrus psyllid (ACP) is an important invasive pest in citrus growing regions of the US which vectors bacteria that causes Huanglongbing disease. Huanglongbing kills citrus trees and reduces the economic viability of citrus production. This pest aggregates and forages on young shoots of citrus flush, especially in the Spring and Summer months. ACP communicates for mating through vibrational calls carried from psyllid to psyllid along the branches of the host citrus trees. Efforts to understand and manipulate ACP vibrational calls are being conducted to reduce ACP populations and the spread of Huanglongbing. Students at the University of Florida and University of Virginia, in collaboration with scientists at the USDA-ARS Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, Florida, discovered that the rate and timing of ACP vibrational calls is affected by the population density in aggregations on citrus flush. At low ACP densities there is potential that the broadcast of synthetic calls can disrupt mating as well as how psyllids find young citrus flush on which they need to forage. This study shows that vibrational disruption of both mating and foraging may be feasible option for control of ACP.

Technical Abstract: Adult Diaphorina citri (ACP) use visual and chemical cues to locate young citrus flush shoots on which they forage and oviposit, and they use vibrational communication duetting calls as cues to help locate mates. For individual pairs, calling and mating usually peaks between 10:00 and 15:00. To explore whether call rates (calls per hour per ACP) are affected by interactions with nearby conspecifics, calls were compared in small citrus trees on which either 5 or 25 ACP female/male pairs had been released. Calls were monitored for 16 h from sunrise (06:00), after which the final positions were noted. Call rates were similar in both treatments during normal mating hours. However, call rates were significantly higher for low density than high density treatments near sunrise, suggesting that calling during this period may be affected by conspecific density. Aggregations on flush were observed at both densities. We discuss the potential that ACP producing calls near sunrise, outside of normal mating hours, might benefit from gains in reproductive fitness in low-density contexts if they call not only to locate mates but also to locate preferred flush, in which case, vibrational disruption of both mating and foraging may be feasible.