Effects of insect longevity and drought conditions on aster leafhopper (Hemiptera: Cicadellidae) fecundity

Authors: ROMERO, BERENICE - University Of Saskatchewan; ENTZ, LAWRENCE - University Of Saskatchewan; Wallis, Christopher; PRAGER, SEAN - University Of Saskatchewan

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/3/2025
Publication Date: 7/2/2025
Citation: Romero, B., Entz, L., Wallis, C.M., Prager, S.M. 2025. Effects of insect longevity and drought conditions on aster leafhopper (Hemiptera: Cicadellidae) fecundity. Environmental Entomology. https://doi.org/10.1093/ee/nvaf068.
DOI: https://doi.org/10.1093/ee/nvaf068

Interpretive Summary: Aster leafhoppers are important vectors of aster yellows phytoplasma, which causes infections of barley that sustainably reduces yield where present. Key to managing aster yellows is to keep aster leafhopper populations under control, and this involves complete understanding of insect reproduction especially factors affecting fecundity. Thus, the impact of water deficit stress on aster leafhopper fecundity was observed, both in terms of the number of eggs and nymphs from individual females as well as the preferences of which plants were fed upon. Amino acid levels also were to shed light on these findings. Knowledge gained from this study will assist in developing improved aster leafhopper population models that are used in integrated management programs.

Technical Abstract: Insect population dynamics profoundly affect the potential for a given species to serve as a pest, highlighting the importance of proper quantification and monitoring of insect reproduction. Important measurements of reproduction include individual female egg load and realized fecundity, which can be affected by insect longevity and host quality. Previous work on age-specific fecundity seemed to indicate that fecundity decreased over time. To evaluate this using aster leafhoppers (Macrosteles quadrilineatus Forbes), newly emerged pairs were caged onto plants, and egg and nymph numbers were determined on a weekly basis until females died. Moreover, water deficit can affect amino acid concentrations in phloem sap, and in turn, render plants more or less palatable and nutritious for insect herbivores. To examine the relationship between water deficit and reproductive potential, aster leafhoppers were reared on water-stressed and unstressed barley plants until adult emergence. Pairs with all possible combinations of leafhoppers from each water stress condition were made and caged onto plants for seven days, after which they were removed, and plants were kept for further analysis. Individual female egg load was determined prior to the start of the experiment, following the seven-day mating period, and following adult emergence of the new generation. Offspring numbers and nymphal development were determined for all crosses. Amino acid concentrations were quantified in water-stressed and unstressed plants. Altogether, findings provide insight into how important factors such as age and abiotic stress on plants can shape aster leafhopper reproduction and population dynamics.