Seasonality in neotropical populations of Plutella xylostella (Lepidoptera): resource availability and migration |
| |
Authors: | Wellington Garcia Campos José H. Schoereder Og F. DeSouza |
| |
Affiliation: | (1) Universidade Federal de São João del Rei, 36301-160 São João del Rei, Brazil;(2) Universidade Federal de Viçosa, Viçosa, Brazil |
| |
Abstract: | The present study aimed to verify (1) whether seasonal increases in neotropical populations of Plutella xylostella are directly provoked by regular influxes of migrants, and (2) whether temporal variation in food availability is the ecological process behind such predictable events. Over 3 years, plants that P. xylostella prefers were cultivated and irrigated in order to provide a continuous and abundant supply of food. Nevertheless, seasonal oscillations in the population of the herbivore still occurred. The hypothesis of seasonal availability of host plants could not explain the population pattern. In April, when the insect was practically extinct from the area, an artificial infestation (immigration) with 10,000 pupae established a precocious population. Therefore, the start of the natural cycles of population growth, during July–August, seems to be due to external factors, rather than an improvement in local conditions for resident individuals. In the beginning of the natural cycles, the increase in the density of adults significantly preceded the increase in immatures. Plutella xylostella does not diapause, and therefore immigration is the proximate cause of the seasonal population increases. Hypotheses about local factors are suggested to explain the decreasing phase of the predictable population cycles. |
| |
Keywords: | Brassicaceae Diamondback moth Dispersal Herbivore Insect Population dynamics Seasonal |
本文献已被 SpringerLink 等数据库收录! |
|