Browsing by Author "Saska, Pavel"

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Bias Introduced by the Simplified Method for the Estimation of the Intrinsic Rate of Increase of Aphid Populations: a Meta-Analysis
(E Schweizerbartsche verlagsbuchhandlung, 2021) Saska, Pavel; Ozgokce, Mehmet Salih; Skuhrovec, Jiri; Atlihan, Remzi; Guncan, Ali; Zamani, Abbas Ali; Tuan, Shu-Jen
The intrinsic rate of increase, denoted as r or r(m), describes the rate of population growth. Simplified formulas for estimating r have been developed to reduce labour and avoid complicated computations. The aim of this paper was to demonstrate and quantify the systematic bias in estimates of the intrinsic rate of increase provided by the simplified method (Wyatt & White 1977) compared to the age-stage, two-sex life table theory using a set of independently collected aphid life tables and meta-analytical approaches. The factors behind the variation in the bias across the studies were also explored. We analysed 112 aphid life tables from 24 independent experiments. The simplified method provided significantly greater estimates of the intrinsic rate of increase than the age-stage, two-sex life table theory in 98 out of 112 life table studies, and the difference was, on average, 27.6 % (95% CI: 24.0-31.3 %). The magnitude of the log-ratio of the two approaches was positively influenced by the pre-reproduction mortality and by variations in the duration of the total pre-reproduction period within a cohort. We concluded that although using simplified methods may be appealing because it saves time during the data collection phase and analysis, researchers, reviewers and journal editors should critically evaluate whether using the simplified method(s) is worthwhile, taking into account that such data are inaccurate and potentially lead to false conclusions. Current advances in the life-table theory and computer capacity have eliminated the need for simplified methods in population ecology.
Fast Population Growth in Physogastry Reproduction of Luciaphorus Perniciosus (Acari: Pygmephoridae) at Different Temperatures
(Oxford Univ Press inc, 2017) Bussaman, Prapassorn; Sa-uth, Chirayu; Chandrapatya, Angsumarn; Atlihan, Remzi; Gokce, Ayhan; Saska, Pavel; Chi, Hsin
Luciaphorus perniciosus Rack is one of the most serious pests of several cultivated mushroom species including Ganoderma lucidum (Fr.), Flammulina velutipes Karst., Auricularia polytricha (Mont.) Saac., Lentinus polychrous Lev., and Lentinus squarrosulus (Mont.) Singer in Thailand. Adult female Lu. perniciosus produce offspring inside their physogastric hysterosomas, with all embryos developing through to the adult stage while remaining in the abdomen. Once the abdomen ruptures, the female parent dies and the offspring consisting of mostly fertilized female adults along with a few male adults continue to emerge from the cadaver of the mother for a period of several days. This peculiar type of reproduction after the death of the mother is a special case for life table analysis and has not been discussed previously in demographic analyses. In this study, the life table data of this mite fed on Le. squarrosulus were collected at 25, 30, and 35 degrees C and analyzed by using the agestage, two-sex life table. The standard errors of population parameters were estimated by using the bootstrap technique (200,000 bootstraps). At 25, 30, and 35 degrees C, females started reproduction at ages 9, 5, and 3 d, respectively; the net reproductive rates (R-0) were 192.27, 253.81, and 234.11 offspring. Due to their rapid development and high fecundity, the r values were as high as 0.4189, 0.8653, and 1.0892 d (1) at 25, 30, and 35 degrees C, respectively. Computer projection indicated that the mushroom mites Lu. perniciosus is capable of a threefold daily increase at 35 degrees C.
Survival and Reproductive Strategies in Two-Spotted Spider Mites: Demographic Analysis of Arrhenotokous Parthenogenesis of Tetranychus Urticae (Acari: Tetranychidae)
(Oxford Univ Press inc, 2016) Tuan, Shu-Jen; Lin, Yung-Hsiang; Yang, Chung-Ming; Atlihan, Remzi; Saska, Pavel; Chi, Hsin
Tetranychus urticae Koch is a cosmopolitan pest whose rapid developmental rate enables it to produce colonies of thousands of individuals within a short time period. When a solitary virgin female colonizes a new host plant, it is capable of producing male offspring through the arrhenotokous parthenogenesis; once her sons mature, oedipal mating occurs and the female will produce bisexual offspring. To analyze the effect of arrhenotokous reproduction on population growth, we devised and compared separate life tables for arrhenotokous and bisexual populations ofT. urticae using the age-stage, two-sex life table theory. For the cohort with bisexual reproduction, the intrinsic rate of increase (r), finite rate (lambda), net reproductive rate (R-0), and mean generation time (T) were 0.2736 d(-1), 1.3146 d(-1), 44.66 offspring, and 13.89 d, respectively. Because only male eggs were produced during the first 8 d of the oviposition period and the cohort would soon begin bisexual reproduction, it would be theoretically wrong to calculate the population parameters using the survival rate and fecundity of an arrhenotokous cohort. We demonstrated that the effect of arrhenotokous reproduction could be accurately described and evaluated using the age-stage, two-sex life table. We also used population projection based on life table data, quantitatively showing the effect that arrhenotokous reproduction has on the growth potential and management ofT. urticae.