Demographic Statistics for the Pea Aphid (Homoptera: Aphididae) in Wisconsin and a Comparison with Other Populations

Publisher Website
Google Scholar
Abstract
The relationship between temperature and nymphal developmental rate for Wisconsin populations of the pea aphid, Acyrthosiphon pisum (Harris), was studied in the laboratory and the field. Laboratory studies provided estimates of both lower (2.73°C) and upper (26.02°C) thresholds for development. Age-specific life table parameters were also estimated for two apterous cohorts and one alate cohort exposed to field temperatures. Population growth statistics varied with rearing temperature but, for apterous cohorts, converged when a physiological time scale (“instar periods”) was used. Although stable stage (instar) distributions for the apterous cohorts varied on a physiological time scale, ca. 50% of the individuals in each cohort were first instars, whereas adults accounted for only 7.6 to 13.1% of the total population. Developmental thresholds and population statistics for A. pisum in Wisconsin were similar to an Ontario (Canada) population established in a climate similar to Wisconsin's, but were dissimilar to a British Columbia population established in a warm, arid region. The relevance of these results to the study of A. pisum population dynamics in the field is discussed.