2 1: 1 7-27 ( 2001) Formosa n Entomol. 2 1 : 1 7-27 (2001) (Orgyia posticus) ( ) * (Orgyia posticus (Walker)) 10 15 20 25 30 35 12L : 12D 25 5 10-35 64.1 40.0 26.2 16.2 16.2 21.1 19.6 16.0 8.2 6.9 6.0 10~30 7.1 6.3 7.1 4.8 3.7 300-510 10 15 20 5.9 4.5 1.5 5.1 2.8 77.39 67.03 85.97 70.41 97.03 3.7 411.2 3.3 2.2 120.32 197.19 (Orgyia posticus (Walker)) Tussock moths 8-9 3-5 Notolophus australis posticus Walker (Guan, 1979) 1988b) (Lymantridae) (Chang, 60-70 (Wu, 1997; Zih, 1985) 1988b) (Su, 1985; Zih, 1985) (Wu, 1977; Chang, * e-mail:clcheng@mail.ncyu.edu.tw 17

Zih (1985) 6-13 13-22 8-22 5-10 4-5 17-27 12L : 24-55 30-61 22-25 15-17 Wu (1977) 30 35 30 Guan (1978) 20% 16.8 5.3 4.3 Su (1985) 20 25 30 5 13 14-19 18-36 6-14 5 16 5 6 3-5 6 K = (T - (9 2 cm) 12D 65±5% 10 15 20 25 35 C)D (K: T: C: D: ) (Nelumbo nucifera) mm 300-510 70% 2. 10 15 20 1. ( A) 1 1-4 18

6-8 1.06±0.09~1.21±0.15 cm 3-5 1-2 ( B) (repugnatorial 0.24±0.02~0.28±0.02 cm gland) 0.46±0.05~0.51±0.04 cm ( E) 0.57±0.03 mm 1.18±0.11~1.32±0.25 cm 1.51±0.24~2.52±0.19 cm 1.94±0.12 mm 1-4 4 8 6 8 8 5 5-8 5 9 8 6 1-4 6-8 10 5 1.69±0.23~2.63±0.26 cm 2.25±0.46~4.0±0.17 cm 2.30±0.40 mm 1-7 8 1 2 3.13±0.29~4.0± 9 4 1-3 ( C) 3. 0.51±0.03~0.55±0.04 cm 1.1 cm 0.65±0.03~0.75±0.26 cm 1.5cm 0.81±0.05 mm ( G) 1-7 2 2.04±0.29~2.17±0.28 cm 1-2 8 4. ( H) 1.28± 0.08~1.54±0.05 cm 2.5 cm 1.24±0.07 mm 8 6-7 ( F) 0.17 cm 2.25±0.46~2.81±0.39 cm 1.53±0.13~1.65±0.25 cm ( D) 0.68±0.04~0.98±0.11 cm 19

A. B. C. D. E. F. G. H. Fig. 1 Orgyia posticus (Walker) A. Eggs; B. First-instar larvae; C. A second-instar larva; D. A third-instar larva; E. A fourth-instar larva; F. A fifth-instar larva; G. A cocoon; H. Adults, left: female, right: male. 20

1/3 2/3 30 16.2 35 2/3 21.1 10 64.1 1.41±0.12~1.72±0.10 cm multiple range test) 10 15 20 25 30 35 25 30 ) 10 30ºC 3.5 ( ) 18.0 2.8 12.4 2.9 25 5.0±1.22 8.4 2.6 10.4 2.2 11.1 95% 35 10 15 20 30 ( ) 3.1 12.5 4.8 13.7 10-30ºC 60.2 10 35ºC 37.7 23.5 14.7 14.8 67.5 41.6 28.8 18.1 17.4 3.4 18.6 2.8 12.5 3.0 9.3 2.9 11.6 3.5 12.1 30ºC 10~35ºC 64.1 40.0 26.2 (Duncan s new ( 3.3 19.6 2.8 12.4 3.1 10.0 25 35ºC 16.2 16.2 21.1 25 11.1 18.5 9.1 30 4.3% Table 1. The developmental period of larval stages of Orgyia posticus at different temperatures Temp. ( ) Developmental period ( days) (x ±SD) 1 st instar 2 nd instar 3 rd instar 4 th instar 5 th instar Total 10 15 20 25 30 35 18.6±0.5 a 8.4±0.3 b 6.1±0.1 c 3.4±0.6 d 3.4±0.2 d 3.4±0.3 d 12.5±0.3 a 6.8±0.3 b 4.3±0.2 c 2.9±0.1 d 2.8±0.1 d 2.9±0.3 d 9.3±0.6 a 6.8±0.4 b 4.8±0.3 c 3.5±0.1 d 3.0±0.7 d 3.6±0.4 d 11.6±0.8 a 8.6±0.3 b 5.2±0.2 c 3.1±0.3 e 2.9±0.2 e 4.1±0.4 d 12.1±1.4 a 9.4±1.1 b 5.8±0.2 c 3.5±0.4 d 3.9±0.7 d 6.7±1.0 c 64.1±3.5 a 40.0±1.0 b 26.2±0.7 c 16.2±0.3 e 16.2±0.5 e 21.1±1.5 d 1) Means with the same letter in the same column do not significantly differ at the significance leavel of 5% according to Duncan s new multiple range test. 21

30% 10ºC 13.3% 2.17±0.26 2.17±0.28 2.04±0.25 2.10±0.21 ( ) 20 30 2.04 cm 10 35 15 2.17 cm 100% 10-30 ( ) 35 19.6 16.0 8.2 6.9 6.0 30 6 10 19.6 15 30 ( ) 10 15 20 25 ( ) 10 30 10 30 22.9 19.9 1.54±0.01 9.4 7.9 7.4 16.5 1.45±0.03 1.42±0.03 1.31±0.03 1.29±0.04 13.4 6.3 4.7 4.8 30 cm 1.72±0.04 7.4 10 22.9 25 4.7 10 16.5 10 30 10 1.72 cm 25 30 1.40 cm 1.60±0.15 1.56±0.19 1.53±0.13 1.65±0.25 1.55±0.22 cm 2.04±0.29 cm 20 1.53 cm 25 1.65 100% 20 25 6.7 6.9% 10 10-30 ( ) ( : ) 1:1.1 1.64±0.02 1.52±0.03 1.40±0.10 1.40±0.08 cm 10 1.54 cm 30 1.29 cm Table 2. Effects of the temperature on the developmental period of larvae and pupae of Orgyia posticus in different sexes Temp. Developmental period ( days) (x ±SD) ( ) 1 st instar 2 nd instar 3 rd instar 4 th instar 5 th instar Larval period Pupal period 10 18.0±1.1 12.4±1.2 8.4±1.5 10.4± 2.6 11.1± 2.9 60.2± 3.5 22.9± 4.3 19.6±2.9 12.4±1.2 10.0±2.1 12.5± 1.1 13.7± 2.0 67.5± 3.5 16.5± 1.7 15 8.5±1.4 6.7±1.7 6.6±0.9 7.9± 1.2 7.9± 2.8 37.7± 0.8 19.9± 1.4 8.4±0.6 6.9±1.4 7.4±1.3 8.9± 0.9 10.0± 0.9 41.6± 1.2 13.4± 1.2 20 6.2±0.9 4.1±0.8 4.4±0.9 4.2± 1.1 4.6± 1.4 23.5± 0.9 9.4± 1.4 6.0±0.7 4.5±0.6 5.1±0.9 6.1± 1.3 7.1± 1.5 28.8± 1.0 6.3± 0.9 25 3.5±0.5 2.8±0.5 3.6±0.5 2.6± 0.7 2.2± 1.1 14.7± 0.6 7.9± 0.9 3.3±0.5 3.1±0.6 3.4±0.5 3.6± 0.5 4.8± 0.7 18.1± 0.7 4.7± 0.7 30 3.6±0.6 2.8±0.5 2.9±0.8 3.1± 0.6 2.9± 1.4 14.8± 0.4 7.4± 0.8 3.5±0.5 2.8±0.4 3.1± 0.6 3.1± 0.5 4.8± 0.8 17.4± 0.8 4.8± 0.8 22

Table 3. Mortaity of larvae and pupae of Orgyia posticus at different temperatures Temp. Mortality(%) ( ) 1 st instar 2 nd instar 3 rd instar 4 th instar 5 th instar Pupa 10 13.3 7.7 0 0 8.3 0 15 0 0 0 0 3.4 0 20 0 0 0 3.3 0 6.7 25 0 0 0 0 0 6.9 30 0 0 0 0 0 0 35 11.1 18.5 9.1 30 4.3 100 Table 4. Pupal period and adult longevity of Orgyia posticus at different temperatures Adult longevity (days) Famale Male Average 10 19.6±0.6 a (22) 6.7±0.9 a (11) 7.4±0.4 b (11) 7.1±3.5 a (22) 15 16.0±1.8 b (29) 6.6±0.4 a (17) 6.6±1.0 bc (12) 6.3±2.4 b (29) 20 8.2±0.4 c (28) 5.8±1.1 a (12) 8.7±1.7 a (16) 7.1±1.9 a (28) 25 6.9±0.9 cd (27) 4.2±0.2 b (9) 5.8±0.3 c (18) 4.8±1.2 c (27) 30 6.0±0.4 d (30) 3.8±0.7 b (16) 4.0±0.5 d (14) 3.7±1.1 d (30) 1) Means with the same letter in the same column do not significantly differ at the significance level of 5% according to Duncan s new multiple range test. 2) Number in parenthesis represents no. of samples. 6.7 30 3.8 10 20 8.7 30 4.0 15 20 25 30 10 15 25 30 20 25 30 25 20 30 ( ) 10-30 7.1 6.3 7.1 4.8 3.7 10 20 7.1 30 (r) 3.7 0.964 0.984 10 10 15 20 0.995 0.972 23

Table 5. Relationship between developmental rate and temperature, and low threshold temperature and effective accumulated temperature for the immature stage of Orgyia posticus Stage Regression equations Correlation coefficient (r) Low development threshold ( ) Thermal summation K(DD) 1 st instar Y=-0.077+0.013X 0.964 5.9 77.39 2 nd instar Y=-0.068+0.015X 0.984 4.5 67.03 3 rd instar Y=-0.018+0.012X 0.995 1.5 85.97 4 th instar Y=-0.077+0.015X 0.972 5.1 70.41 5 th instar Y=-0.028+0.010X 0.920 2.8 97.03 Larval stage Y=-0.011+0.003X 0.972 3.7 411.20 Male pupa Y=-0.011+0.005X 0.957 2.2 197.19 Female pupa Y=-0.030+0.009X 0.947 3.3 120.32 0.920 0.957 0.947 25 ( ) 5.9 4.5 1.5 10 35 5.1 2.8 77.39 10 15 67.03 85.97 70.41 97.03 20 25 30 3.7 35 411.2 2.7 10 35 159.74 64.1 40.0 2.2 3.3 26.2 16.2 16.2 21.1 10 30 197.19 120.32 Su(1985) 20 10 15 25 30 11.29 7.0 6 25 90% 67.5 41.6 28.8 18.1 17.4 10 15 20 25 30 60.2 37.7 23.5 14.7 14.8 25 5.0 95% 35 25 30 16.2±0.3 16.2±0.5 20 25 30 Su (1985) 20 25 30 Su (1985) 32.99 24.70 22.37 24

26.28 19.43 16.63 10 30 Su (1985) 20 25 30 31% 20 3.3% 7.4 6.6 8.7 5.8 4.0 35 20 ( 60%) 35 Su (1985) 20 25 25 30 30 5.10 4.58 6.9 6 3.15 5.70 5.33 25~30 5.61 10 30 16.5 13.4 6.3 4.7 4.8 22.9 19.9 9.4 7.9 7.4 Su (1985) 20 25 30 5.9 1.5 11.35 5.63 5.17 97.03 13.00 8.28 7.92 67.03 3.3 2.2 120.32 Su 197.19 Su (1985) 15.08 11.23 10~30 55.86 114.03 0 0 6.7 6.9 0% Su (1985) 6.7 6.6 5.8 4.2 3.8 20 20 25 30 6 4 4% 35 100% 25

Su, C. Y. 1985. Influence of temperature on Chang, C. P. 1988a. The investigation on insect and other animal pests on grapevine and their seasonal occurrences in Taiwan. Chinese J. Entomol. 8(1): 39-49 (in Chinese). Chang, C. P. 1988b. The ecology and control of insects and other animal pests on grapevine. Chinese J. Entomol., Special Publ. 2: 11-31 (in Chinese). Guan, C. J. 1979. Notolophus australis posticus Walker pp.338-340. In: Forest Entomology. Li-Ming Cultural. Enterprises, Taipei 554 pp. (in Chinese). life stages and leaf consumption of Porthesia taiwana and Orgyia posticus on soybean leaf. Chinese J. Entomol. 5(1): 53-61 (in Chinese). Wu, L. L. 1977. A survey study of the injurious insects of grape-vine in Taiwan. Plant Prot. Bull. 19(2): 78-100 (in Chinese). Zih, S. T. 1985. Notolophus australis posticus Walker. pp.121-123. In: Economical Entomology. Cheng Chung Book Co., Taipei, 464 pp. (in Chinese). 2000 11 13 2000 12 27 26

Morphology of Orgyia posticus (Lepidoptera: Lymantridae) and the Effects of Temperatures on Its Development Chiou-Ling Cheng *, Shwn-Miin Yang and Ming-Fa Cheng Department of Biological Resource s, National Chiayi University. Chiayi, 60083, Taiwan, R.O.C. ABSTRACT Orgyia posticus (Walker) is one of the important insect pests of Lymantridae in Taiwan. The development of O. posticus was investigated at various temperatures in a 12L : 12D photoperiod with the leaves of Nelumbo nucifera. The egg stage required 5 days at 25. Under 10, 15, 20, 25, 30, and 35, the larval development took 64.1, 40.0, 26.2, 16.2, 16.2, and 21.1 days, respectively. While pupal development took 19.6, 16.0, 8.2, 6.9, and 6.0 days, respectively. The longevity of adults was 7.1, 6.3, 7.1, 4.8, and 3.7 days from 10 to 30. The number of eggs laid by a female was 300-501. O. posticus needed 33 days to complete a life cycle at 25. On average, the egg, larva, pupa, and adult took 5, 16.2, 6.9, and 4.8 days to complete its stage, respectively. Larvae have color dimorphism: the winter form showed from 10 to 15, and the summer form showed from 20 to 35. The temperatures of the development threshold for 1 st -, 2 nd -, 3 rd -, 4 th -, and 5 th -instar larvae were estimated to be 5.9, 4.5, 1.5, 5.1, and 2, respectively. The sums of the effective accumulated temperature for 1 st -, 2 nd -, 3 rd -, 4 th - and 5 th -instar larvae were 77.39, 67.03, 85.97, 70.41, and 97.03 degree-days (DD), respectively. The threshold temperature and effective accumulated temperature for larvae were 3.7 and 411.2 degree-days. The threshold temperature of female and male pupae were 3.3 and 2.2, and effective accumulated temperatures were 120.32 and 197.19 degree-days, respectively. External morphology in each stage of this moth are also described and illustrated in the paper. Key words: Orgyia posticus, morphology, life cycle, temperature of development threshold, effective accumulated temperature. 27