Effect of temperature on life table parameters of Leptocybe invasa (Hymenoptera: Eulophidae).
Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae) first described in 2004, is a new eucalyptus pest of global importance. A thorough understanding of pest biology is essential for development of a reliable pest population prediction system and management strategies, but little is known about this pest. Therefore, we quantified the development, fecundity, fertility, longevity, morphometrics (length, width, and hind tibia length of adults), and other life table parameters of L. invasa in relation to temperature and to provide an experimental basis for developing an overall wasp population model. The results showed that ranging from 20 to 32°C (five constant temperatures were 20, 23, 26, 29 and 32°C, respectively), the developmental period of immatures (egg to adult) was shortest at 29°C but longest at 20°C; the number of eggs per female in the oviduct and survival rate of immatures were greatest at 29°C but smallest at 32°C. The effect of temperature on morphometrics was more pronounced for females than males. When L. invasa was fed with a 40% honey solution, maximum longevity was at 23°C (9.0 days for females and 12.8 days for males). The intrinsic rate of natural increase (rm) was largest (0.0477) at 29°C, and the sex ratio of L. invasa was extremely female-biased. The intrinsic rate of natural increase (rm) indicates that L. invasa population growth is likely to be greatest at 29°C. The developmental zero temperature (t) and the effective cumulative temperature (k) of egg, larva and pupa were 13.0, 19.7 and 17.1°C, and 128.1, 284.2 and 201.2°C, respectively. For L. invasa, 19.1°C (t) and 563.5°C (k) were indispensable for completing development from egg to adult. Therefore, farmers or managers of forests could predict the population dynamics of the wasp and adopt physical or chemical methods to control it according to the temperature.