1 3 Appl Entomol Zool (2016) 51:71–80 DOI 10.1007/s13355-015-0372-5 ORIGINAL RESEARCH PAPER Lower development threshold temperatures and thermal constants for four species of Asphondylia (Diptera: Cecidomyiidae) in Japan and their larval developmental delay caused by heat stress Junichi Yukawa 1 · Minami Ichinose 1 · Wanggyu Kim 1 · Nami Uechi 2 · Naohisa Gyoutoku 3 · Tomohisa Fujii 4 Received: 9 July 2015 / Accepted: 28 September 2015 / Published online: 20 October 2015 © The Japanese Society of Applied Entomology and Zoology 2015 infestation range expands every summer and autumn from southern to northern Honshu, where winter–spring hosts have never been detected. The larval development of A. yushimai and A. baca, as well as those of two other uni- voltine congeners, A. aucubae Yukawa and Ohsaki and A. sphaera Monzen, was delayed at temperatures of 26, 28, or 29 °C. Global warming, when it becomes more prominent, will reduce the number of generations and the survival rate of multivoltine gall midges that spend summer without diapause. Keywords Gall midge · Heat stress · Host alternation · Soybean · Summer diapause · Temperature Introduction Among various direct and indirect effects of climate change on insect life (e.g., Ladányi and Horváth 2010), heat stress has been receiving more attention than before because it had not been previously discussed intensively in relation to global warming (e.g., Kingsolver et al. 2013; Kiritani 2012; Kiritani and Yukawa 2010). Bale et al. (2002) stated that the effects of temperature change are frequently con- tradictory. Higher temperatures can help to accelerate the development of individuals and increase the survival rate, but these can be accompanied by lower adult body mass and lower fertility. Musolin et al. (2009) demonstrated that the southern green stinkbug, Nezara viridula (Linnaeus) (Hemiptera: Pentatomidae), suffered heat stress when it was reared from egg to adult in an incubator set at a tem- perature 2.5 °C higher than outdoor ambient temperature. Heat stress affected N. viridula more severely in summer than in other seasons: body size became much smaller than that of outdoor populations, development was delayed, and Abstract Lower development threshold temperatures (LDT) of gall midges (Diptera: Cecidomyiidae) were directly determined by comparing developmental stages before and after incubation of galls for a definite period under a range of temperatures sufficient to cover the bor- ders of the linear response. The LDT was determined to be 15 and 17 °C, respectively, for the soybean-pod gall midge, Asphondylia yushimai Yukawa and Uechi, and the ampelopsis fruit-gall midge, A. baca Monzen. They are host-alternating multivoltine species, but their LDT did not differ between generations on winter–spring and sum- mer–autumn hosts, supporting the hypothesis that the value of LDT is stable and species specific. Based on the LDT and the 50 % emergence dates (ET 50 ) of an overwintered generation, we estimated the thermal constants from first instars to adults to be 47.4 day-degrees for A. yushimai and 164.9 day-degrees for A. baca. The estimated thermal con- stant enables A. yushimai to repeat many generations annu- ally, which may support the possibility that the gall-midge Electronic supplementary material The online version of this article (doi:10.1007/s13355-015-0372-5) contains supplementary material, which is available to authorized users. * Junichi Yukawa JZS02305@nifty.ne.jp 1 Entomological Laboratory, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan 2 NARO Institute of Fruit Tree Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8605, Japan 3 Yamagawa, Kurume, Fukuoka 839-0817, Japan 4 Biosystematics Laboratory, Graduate School of Social and Cultural Studies, Kyushu University, Motooka, Fukuoka 819-0395, Japan