Temperature/development relationships in bluegreen lucerne aphid, Acyrthosiphon kondoi Shinji, were studied at 5 constant temperatures between 6°C and 30°C using aphids held individually in stem cages. All biological variables recorded showed strong associations with temperature. Reproduction was clearly modified by temperature, increasing temperature reducing the pre-oviposition period, total reproductive period, and total number of progeny produced; maxima were at 11°C for these variables. No aphids survived at 30°C, and at 25.SoC there was limited reproductive success. There were generally 4 instars, but up to 15% of aphids went through 5 instars. Development rate showed a linear relationship with temperature between 6°C and 20.5°C; extrapolation indicated a lower threshold for development of 2.63°C. Using this threshold value, developmental comparisons expressed in terms of physiological time (day degrees, DO) showed that all instars were similar in duration (38.4 DO each). The rate of generation completion was approximately 3 times as long as doubling time (145 DO, as against 46 DO). Comparison of life tables for progeny from alate and apterous maternal morphs showed significant differences in the intercepts of regression for the intrinsic rate of increase and the doubling rate against temperature. Possible implications of these differences in performance of progeny from the 2 morphs are discussed.

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Pollen germination on excised nashi (Pyrus serotina Rehder var. culta Rehder) styles was compared at six constant temperatures (4, 17, 12, 16, 20, and 25°C). After 24 h pollen germination was highest at 12°C for the cultivar 'Shinsui'. For the cultivars 'Hosui', 'Kosui', 'Nijisseiki', and 'Shinseiki', the optimum temperature for pollen germination was between 16 and 20°C. The (greenskinned) cultivars 'Nijisseiki' and 'Shinseiki' showed higher levels of pollen germination and a higher optimum temperature than the (russeted) cultivars-'Hosui', 'Kosui', and 'Shinsui'. Field temperatures over the flowering period were lower than these in vitro optima, and so may have contributed to the varying levels of seed set observed.