The effect of temperature on development and fecundity of Scymnus levaillanti

Development and fecundity of Scymnus levaillanti (Mulsant) were recorded at five constant temperatures ranging from 15 to 35 ± 1 °C in 5 °C increments, 60 ± 5% RH and 16 h of artificial light (5000 Lux). Developmental time (egg to adult) of S. levaillanti significantly decreased with increasing temperatures, ranging from 63.9 days at 15 °C to 11.1 days at 35 °C. Development from egg to adult required 305.2 DD above a developmental threshold estimated as 11.7 °C. Oviposition periods lasted 86.5, 76.1, 47.2, and 31.5 days at 20, 25, 30 and 35 °C, respectively. No eggs were deposited at 15 °C. Higher temperatures resulted in shorter generation times (TO) and in decreased net reproductive rates (RO) of the coccinellid. S. levaillanti kept at 30 °C produced 0.151 females/female/day, the highest per capita rate of population growth (rm). The 'functional response' of larvae and adults of S. levaillanti matches well that described by Holling (1959) as Type 2. Daily number of eggs deposited by females increased to a plateau with increasing prey density, Results obtained here provide information about the biology of S. levaillanti, and its feeding capacity indicates that it may act as an important control agent

Age-stage, two-sex life table: The basis of population ecology, biological control and pest management [Yaş ve döneme özgü, iki eşeyli yaşam çizelgesi: Populasyon ekolojisi, biyolojik savaş ve zararlı yönetiminin temeli]

Because they are capable of providing an integrated and comprehensive description of numerous biological parameters (survival, development, fecundity, etc.) of a population, life tables are one of the most powerful tools available for biologists and other researchers conducting research on population ecology, biological control, and pest management. Since the traditional female age-specific life tables ignore the male population and stage differentiation, their use often results in errors and inaccuracies. This article was prepared to discuss the reasons and advantages of using the age-stage, two-sex life table. © 2018, Centenary University. All rights reserved

Host plants mixture and fitness of Kolla paulula: with an evaluation of the application of Weibull function

WOS: 000400943500001The xylem-feeding leafhopper Kolla paulula (Walker), a vector of Pierce's disease, occurs primarily on weeds in and around fruit and ornamental crop orchards in Taiwan. Because our preliminary studies showed that K. paulula performed poorly when reared on pilose beggarticks (Bidens pilosa L. var. radiata) (PB) or trilobate wedelia (Wedelia triloba (L.)) (TW) alone, we collected the life table data of K. paulula reared on a mixture of both host plants to determine the effect at the population level. During their lifespan, 95.6% of feeding time was spent on the major host plant (PB) and only 4.4% on the minor host plant (TW). The intrinsic rate of increase (r), finite rate of increase (), net reproduction rate (R-0) and mean generation time (T) of K. paulula were 0.0487, 1.0500day(-1), 35.86 offspring and 73.4days, respectively. Because more than 95% of the insects have been observed feeding on both plants, this would indicate that the minor host plant may play an important role in the fitness of K. paulula regardless of the short feeding time. We calculated the percentage contribution to the population parameters made by females that had fed on both PB and TW and compared these with the values obtained for offspring of females that had fed solely on PB. We also evaluated the usefulness of applying the Weibull distribution in demographic studies. We demonstrated that when there is a higher mortality in specific life stages, the fitted Weibull distribution would be inaccurate in describing the survival curve and that application of the fitted curve to the calculation of life expectancy or other statistics would result in significant discrepancy to the actual curve.Bureau of Animal and Plant Health Inspection and Quarantine, Taiwan [99AS-9.3.1-BQ-B2(4), 100AS-9.3.1-BQ-B1 (7), 101AS-10.2.1-BQ-B4(1)]; MOST [102-2313-B-005-028, 103-2923-B-005-003]; Czech Science Foundation: CSF [14-13119J]We are grateful to Dr. Hsien-Tzung Shih, Taiwan Agricultural Research Institute, COA, for his assistance in rearing techniques for K. paulula. This project was partly supported by grants from the Bureau of Animal and Plant Health Inspection and Quarantine, Taiwan (99AS-9.3.1-BQ-B2(4); 100AS-9.3.1-BQ-B1 (7); 101AS-10.2.1-BQ-B4(1)), and partly by MOST 102-2313-B-005-028, MOST 103-2923-B-005-003 to SJ Tuan, and Czech Science Foundation: CSF grant 14-13119J to Pavel Saska

Host plants mixture and fitness of Kolla paulula: with an evaluation of the application of Weibull function

The xylem‐feeding leafhopper Kolla paulula (Walker), a vector of Pierce's disease, occurs primarily on weeds in and around fruit and ornamental crop orchards in Taiwan. Because our preliminary studies showed that K. paulula performed poorly when reared on pilose beggarticks (Bidens pilosa L. var. radiata) (PB) or trilobate wedelia (Wedelia triloba (L.)) (TW) alone, we collected the life table data of K. paulula reared on a mixture of both host plants to determine the effect at the population level. During their lifespan, 95.6% of feeding time was spent on the major host plant (PB) and only 4.4% on the minor host plant (TW). The intrinsic rate of increase (r), finite rate of increase (λ), net reproduction rate (R0) and mean generation time (T) of K. paulula were 0.0487, 1.0500 day−1, 35.86 offspring and 73.4 days, respectively. Because more than 95% of the insects have been observed feeding on both plants, this would indicate that the minor host plant may play an important role in the fitness of K. paulula regardless of the short feeding time. We calculated the percentage contribution to the population parameters made by females that had fed on both PB and TW and compared these with the values obtained for offspring of females that had fed solely on PB. We also evaluated the usefulness of applying the Weibull distribution in demographic studies. We demonstrated that when there is a higher mortality in specific life stages, the fitted Weibull distribution would be inaccurate in describing the survival curve and that application of the fitted curve to the calculation of life expectancy or other statistics would result in significant discrepancy to the actual curve