Probability model for the postflight fecundity of viviparous alatae infected preflight by the obligate aphid pathogen Pandora neoaphidis

Flight dispersal enables aphids to locate suitable plants and is regarded as a possible means to allow the dissemination of obligate aphid-pathogenic fungi among hosts. To quantify postflight colonization and fecundity potential of pathogen-infected alates, 688 alates of Myzus persicae and Sitobion avenae were exposed to conidial showers of the common aphid pathogen Pandora neoaphidis, allowed to fly for 0.01–10.2 km in a flight mill system, and then individually reared to monitor their performance under laboratory conditions. Cumulative probabilities [P (m ⩽ N)] for the counts of infected alates producing m nymphs per capita (m ⩽ N) before they became mycosed and of uninfected alates of each aphid species during the same period of colonization fit a logistic model P (m ⩽ N) = 1/[1 + exp (a + rm)] (r2 ⩾ 0.98), yielding a solution to the probability of alates with a specific fecundity, pm = P (m ⩽ N)–P [m ⩽ (N − 1)]. The fitted models indicate that, prior to mycosis, infected alates of both aphid species can produce sufficient progeny for initiation and transmission of mycosis in new colonies although their postflight fecundity potential was greatly reduced due to infection by P. neoaphidis.