A new collembolan species (Paranura rosea) which was native to Korea was selected for evaluating the effect of temperature on their biology. Development, and reproduction of P. rosea were investigated at 15, 20, 25 and 30℃ Hatchability of egg was not affected by experimental temperature, and the lower threshold temperature for development of P. rosea was estimated to be 7.53℃. The temperature reduced the juvenile and adult (maturity period). The intrinsic rate of natural increase and finite rate of increase per week at 20℃ which are maximum values showed significant difference with other experimental temperatures. Survival rate, cumulative reproduction and head capsule width was fitted by several models. Especially, the model which fitted for estimating head capsule width was used to determine their life stage. Estimated head capsule width of P. rosea at the initial oviposition varied with temperature from 0.36 ± 0.007 to 0.45 ± 0.007 with maximum at 20℃ and minimum at 30℃, and significant difference was observed at all the experimental temperature (P<0.05). However, estimated head capsule width at the last oviposition showed different statistically result at only 30℃. Molting frequency per week of one P. rosea was increased as the temperature increased. Based on this study, temperature greatly influenced on their life stage and reproduction. Therefore, relationship between temperature and P. rosea is very important for understanding their biology.

In this study, the toxic effects of fenoxycarb on biological traits of nontarger arthropod P. rosea, Collembola. The tests were assessed in the OECD artificial soil under two different exposure condtions, one was exposed in the bulk soil, and the other was exposed in the compacted soil which unidirectional force was applied to the soil surface. In the bulk system, survived adults and hatched juveniles were counted after 28-day exposures, and in the compact system, survived adults, eggs, hatched juveniles and molts were counted everyday until no more hatching. The toxic effect of fenoxycarb on survival and juvenile production of P. rosea in the bulk system was more toxic than that of the compact system. Juveniles and eggs were seriously affected as compared with toxic effect for adults. Particularly, toxic effect on hatching rate (3.75 mg/kg EC50juvenile) were very higher than that on oviposition (200.868 mg/kg EC50egg) or survival rate of adults ( >1200 mg/kg LC50). The molting freauency of P. rosea was decreased in a concentration dependent manner. These results suggest that the IGRs fenoxycarb exhibit significant impacts on the biological traits of non-target organisms P. rosea and its toxic effects are differently assessed depending on the exposure conditions.

The use of insect growth regulators (IGRs) has been gaining popularity as an environmentally friendly option to improve existing integrated pest management (IPM) strategies. Although IGRs have a selective effect on target organisms, they may exert a more selective effect on non-target organisms. In this study, the toxic effects of teflubenzuron on biological traits of P. rosea, Collembola, were assessed in the OECD artificial soil under two different exposure conditions, one was exposed in the bulk soil, and the other was exposed in the compacted soil which unidirectional force was applied to the soil surface. After 28 days of exposure, the toxicity of teflubenzuron on the survival and juvenile production of P. rosea in the bulk system was more toxic than that of the compact system. Moreover, not only the egg production but also the hatching rate and molting frequency of P. roseas was decreased in a concentration dependent manner. These results suggest that the IGRs teflubenzuron exhibit significant impacts on the biological traits of non-target organisms P. rosea and its toxic effects are differently assessed depending on the exposure conditions.

In Korea very few studies have been conducted in relation to collembola sensitivity to pollutants in populations exposed to soil contaminants in particular heavy metals. The objective of the current research were to study the thermal effects of selected heavy metals on the survival and reproduction of P. rosea in order to assess its applicability as a test species. Petri dishes (87 mm diameter, 15 mm height) were used for compact soil toxicity test and were filled to a depth of 0.5 mm with 6 g artificial soil and 3.5 mL distilled water was added. 20 adults (6 weeks from egg stage) were introduced to each petri dish and placed in two incubators set at 20℃ and 25℃, respectively under continuous darkness. The 28 days EC50s for cadmium in compact soil at 20℃ and 25℃ were 48.9031 and 91.3585 mg/kg, respectively. This thermal toxicity test of P. rosea is advantageous for various environmental sudies, such as toxicity tests.

In this study, egg hatching and larval development of Paranura rosea were experimented at different temperature conditions. The development was studied at four different temperatures, ranging from 15 to 30℃ (in 5℃ intervals), under a dark. As a result, the egg hatching time decreased from 21.67±1.99 to 6.57±1.96 days as the temperature increased from 15 to 30℃. The highest egg hatching rate was 49.27±20.69% at 25℃, where as the lowest rate was 27.97±23.06% at 15℃. The developmental rate increased gradually with temperatures from 15 to 30℃, and the developmental rate was highest at 30℃. The survival rate was highest at 15℃ (85.27 %) and lowest at 30℃ (57.53 %). This wide thermal adaptation in egg hatching and larval development of Paranura rosea is advantageous for various environmental sudies, such as toxicity tests.

Determining age distributions of insect is required for many basic ecological studies. Most of insect developmental studies, the head capsule width and other developmental traits have been widely used to distinguish the instars. Unlike to other insect species, collembolan continues to molt after they reach sexual maturity. So these traits sometimes make it difficult to conduct developmental studies. Model animal used in this study was Paranura rosea a native collembolan speciese. To determine the age groups of P. rosea, we periodically (1week) made digital images of P. rosea (over 100 different images) under the magnifier (DIMIS-M) for consecutive 20 week. And then the head capsule width and the surface area of P. rosea were analyzed using a image software (ImageJ). In this test the head capsule widths and surface area were set as developmental parameters. Both two developmental parameters showed time-dependent increase patterns. And they gave good agreements between predicted developmental parameters and observed parameters (r2=0.83 and 0.71). Based on the reproducibility of juveniles and statistical mean separation tests (tukey's test), both two developmental parameters could be divided into 3 age groups. The information given this study will be used as a basis for understanding the population dynamics and other ecological research.

As a fundamental study for chronic test (definitive test), the range finding test must have been done prior to conducting chronic test. The aims of this study were 1) to search the effective concentration range of two different heavy metals (cadmium and nickel) to indigenous collembolan species (Paranura rosea) 2) to compare the toxicity of cadmium and nickel depending on exposure durations. Toxicity tests were conducted in accordance with the standardized toxicity test proposed by OECD. In this study, there were no mortality occurred at all test concentrations for 7-days exposure. In contrast to 7-days exposure, there were slight increases in mortalities were observed at the concentration higher than 400 mg/kg for both heavy metals for 14-days exposure. The estimated LC50s for cadmium and nickel were 3980.65 (2036.08-64668.61) and 1597.85 (1087.87-3817.61) mg/kg, respectively. The results of this study may be used as a fundamental toxicity data for two heavy metals to proceed in chronic test in the future study.