Transmission and temporal dynamics of anther‐smut disease (Microbotryum) on alpine carnation (Dianthus pavonius). (13th March 2017)

• Record Type: Journal Article
• Authors: Bruns, Emily L.; Antonovics, Janis; Carasso, Valentina; Hood, Michael
• Editors: Power, Alison
• Is Part Of: Journal of ecology. Volume 105:Number 5(2017:Sep.)
• Page Start: 1413
• Page End: 1424
• Publication Date: 2017-03-13
• Subjects: age‐specific resistance -- demography -- epidemiology -- frequency‐dependent transmission -- mixed transmission -- plant pathogen -- sterilizing disease -- vector transmission; Plant ecology -- Periodicals; 577.05
• DOI: 10.1111/1365-2745.12751
• Languages: English
• ISSNs: 0022-0477

Abstract

Summary: Theory has shown that sterilizing diseases with frequency‐dependent transmission (characteristics shared by many sexually transmitted diseases) can drive host populations to extinction. Anther‐smut disease (caused by Microbotryum sp.) has become a model plant pathogen system for studying the dynamics of vector‐ and sexually transmitted diseases: infected individuals are sterilized, producing spores instead of pollen, and the disease is spread between reproductive individuals by insect pollinators. We investigated anther‐smut disease in a heavily infected population of Dianthus pavonius (alpine carnation) over an 8‐year period to determine disease impacts on host population dynamics. Over the 8 years, disease prevalence remained consistently high (>40%), while the host population numbers declined by over 50%. The observed rate of vector transmission to reproductive, adult hosts was inadequate to explain the high disease prevalence. Additional density‐dependent aerial transmission to highly susceptible juveniles, indicated from experimental field and greenhouse studies, is likely to play a key role in maintaining the high disease prevalence. Epidemiological models that accounted for the mixed transmission mode predicted an eventual decline in disease. Synthesis . Our results demonstrate that high prevalence of a sterilizing disease does not necessarily drive host populations towards extinction and also highlights the importance of demographic studies for establishing the presence of alternative transmission modes. Abstract : We studied the transmission dynamics of vector‐borne sterilizing disease in a heavily diseased natural plant population for 8 years. Our results demonstrate that high disease prevalence does not necessarily drive host populations towards extinction and also highlights the importance of demographic studies for establishing the presence of alternative transmission modes.