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

Abstract

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.

Demography and Mass Rearing of the Medicinal Blister Beetle Epicauta impressicornis (Pic) (Coleoptera: Meloidae) at Different Temperatures

“…However, due to its unusual life history and reproduction, there are still many unknown features that need to be understood when attempting to rear the species. Similar to the leafhopper, Kolla paulula (Walker) (Hemiptera: Cicadellidae) (Tuan et al 2017), E. impressicornis showed good fitness when reared on a mixture of leaves from V. faba leaf and S. nigrum along with fruit from C. moschata including beans and melons. However, the physiological mechanism involved in feeding mixed host plants needs further study.…”

Age-stage two-sex life table analysis ofEristalinus aeneus(Diptera, Syrphidae) reared with two different larval media

“…Although the highest life expectancy is commonly associated with the first day of the population, in these two media the highest peaks are found after noteworthy mortality events (Tuan et al, 2017), for instance on the 4th day (figs 2 and 3), one day after the critical mortality detected in the first larval instar in both populations, especially when SOG was used. The population reared with BSG stands out for being the one in which the male adults present the highest life expectancy since this was the long-lived stage.…”

Population characteristics of Macrocheles glaber (Acari: Macrochelidae) and Stratiolaelaps scimitus (Acari: Laelapidae) reared on a mushroom fly Coboldia fuscipes (Diptera: Scatopsidae)

“…The variances and standard errors of the development time, longevity, fecundity and population parameters were analyzed by the bootstrap method with 200 000 bootstraps (Efron & Tibshirani, ; Polat‐Akköprü et al ., ; Tuan et al ., ). The differences between two predator mites were compared by the paired bootstrap test (Efron & Tibshirani, ; Polat‐Akköprü et al ., ).…”