Premium
Inter‐ and intra‐population differences in the effects of temperature on postdiapause development of Delia radicum
Author(s) -
Turnock W. J.,
Boivin G.
Publication year - 1997
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1046/j.1570-7458.1997.00223.x
Subject(s) - biology , population , degree (music) , ecology , demography , physics , sociology , acoustics
Canadian populations of D. radicum differ in their response to temperature during postdiapause development. Populations that are primarily of the early‐emerging type ( ≤256 DD 04 ) (St‐Jean, Quebec; London, Ontario) have high values for the parameters describing this response: R m = 12.7–13.3; T m = 28.0–31.8 °C; T σ = 10.3–14.2 ( R m , the maximum developmental rate at the temperature, T m [ °C ] where the developmental rate is highest, and T σ , the parameter which gives the shape of the truncated normal curve fitted to the data), a low degree‐day requirement for emergence ( 160–232 DD 04 ), and may lack a developmental delay at temperatures above ca. 21 °C. Populations of the late‐emerging type (Kildare, Prince Edward Island) have low parameter values ( R m = 2.5, T m = 19.3 °C; T σ = 6.4 ), high degree‐day requirements ( 530 DD 04 ), and a developmental delay at high temperatures. The parameters for the early‐emergers in the population from Winnipeg, Manitoba (74% early) were intermediate ( R m = 9.1, T m = 27.1 °C, T σ = 10.7, DD 04 = 246 ), but resembled the early rather than the late type. This population varied from 31 to 90% early type over a 10‐year period and the rate of postdiapause development at 20 °C was directly related to the percentage early. In the year with the most rapid development (90% early), development was significantly slower than in the populations from other locations with predominantly early populations, and the year with the slowest development (31% early) showed significantly faster development than that from Kildare, Prince Edward Island (100% late). Therefore the parameters for early and late types of development will not be accurate for use in mixed populations, and the parameters in mixed populations will change among years. Populations of D. radicum in North America and Europe (67 locations by years) varied from 0–100% early. At Winnipeg, the percentage early was directly related to the annual temperature accumulation ( DD 05 ) during the growing season. The calculation of developmental parameters for the early‐emergers of mixed populations provides a more accurate basis for estimating the times of first emergence and the first peak of emergence than parameters based on the whole population. Since postdiapause developmental rates vary both among and annually within locations, developmental models should be designed to include such variations.