Temperature-dependent demography of Aulacaspis yasumatsui (Hemiptera: Diaspididae).

Aulacaspis yasumatsui Takagi continues to threaten the extinction of the endemic and endangered Cycas taitungensis (Shen et al.) in Taiwan. Failure to understand its population demographic parameters in detail will continue to hinder the success of pest management practices. An in-depth knowledge of the development, survival, and fecundity of A. yasumatsui under different environmental conditions is necessary to understand its' population growth. The demography of A. yasumatsui was studied in the laboratory based on the age-stage, two-sex life table at 20, 23, 25, 28, and 31 degrees C, 70% relative humidity, and a photoperiod of 16:8 (L:D) h. The intrinsic rate of increase (r) under these temperatures was 0.06, 0.07, 0.09, 0.10, and 0.08 d(-1), respectively. The net reproductive rate (R0) was 46.27, 47.78, 69.50, 96.08, and 56.65 offsprings per individual and the mean generation time (T) was 65.60, 55.81, 47.82, 44.15, and 51.42 d, respectively. A. yasumatsui does well at warmer temperatures (25-28 degrees C); however, its performance is disrupted at lower temperatures. This study provides insight on how to minimize growth and destruction of A. yasumatsui and conservation of Cy. taitungensis; new cycad reserves should be set up in cooler areas in Taiwan.

Temperature-dependent demography of Chilades pandava peripatria (Lepidoptera: Lycaenidae).

Chilades pandava peripatria Hsu and its host plant Cycas taitungensis Shen, Hill, Tsou & Chen are both endemic species to Taiwan. Ch. pandava peripatria has a specific association with buds and soft leaves of cycad plants. The introduced species, Cy. revoluta, have prolonged budding periods and extensive auxiliary buds that extensively contribute to the outbreak of Ch. pandava peripatria. An in-depth knowledge of the development, survival, and fecundity of Ch. pandava peripatria under different environmental conditions is necessary to understand the population growth of Ch. pandava peripatria. The demography of Ch. pandava peripatria was studied based on the age-stage, two-sex life table at 20, 23, 25, 28, and 31 degrees C, 70% RH, and a photoperiod of 16:8 (L:D) h under laboratory conditions. Ch. pandava peripatria completed its development under tested temperatures but did not produce offsprings at 23 degrees C. Because of the high egg mortality at 20 degrees C, the data at this given temperature were excluded from this study. The intrinsic rate of increase (r) under these tested temperatures was 0.1846, 0.2919, and 0.1412 d(-1), respectively. The net reproductive rate (H(o)) was 165.47, 262.32, and 56.68 offsprings per individual and the mean generation time (T) was 27.72, 19.10, and 28.67 d, respectively. Our results indicated that Ch. pandava peripatria is highly adaptable to environments where temperature ranges from 25 to 31 degrees C.

Effects of irradiation on Planococcus minor (Hemiptera: Pseudococcidae).

Irradiation has been recognized and endorsed as a potential phytosanitary measure that could be an alternative to current quarantine treatments. Dosages of 50, 100, 150, 200, and 250 Gy were used to irradiate three different life stages (eggs, immatures, and adults) of Planococcus minor (Maskell) (Hemiptera: Pseudococcidae), focusing on females due to its parthenogenesis ability, with an aim to find the most tolerant stage and the most optimal dose to control P. minor. Cobalt 60 was the source of irradiation used. Irradiation of 150-250 Gy has a significant effect on all life stages of P. minor, decreasing its survival rate, percentage of adult reproduction, oviposition, and fertility rate. The adult was the most tolerant life stage in both mortality and fertility rate. All the different irradiated target life stage groups oviposited eggs, but none of the F2 eggs hatched at the most optimal dosage of 150-250 Gy.