Thermal biology of Tuta absoluta: demographic parameters and facultative diapause

The South American tomato pinworm, Tuta absoluta, (SATP) is now a devastating pest worldwide of crops in the family Solanaceae. Most prior studies of SATP’s thermal biology were based on populations from tropical regions, and proved unsuitable for explaining its invasion of large areas of the Palearctic. A more holistic approach to the analysis of its thermal biology is essential background for developing models to assess its invasive potential. Our studies found that SATP has lower and upper thermal thresholds (θL = 5.37 °C and θU = 35.69 °C, respectively) than South American populations used in prior studies (θL = 7.38 °C and θU = 33.82 °C). Age-specific life tables were used to estimate the effects of temperature on its demographic parameters. Diapause in SATP had not been characterized prior to our study. We found facultative diapause in pupae developing from larvae exposed to relatively low temperatures (i.e., 2 and 5 °C) and short-day length for different exposure periods. The strength of diapause was measured as an increase in post-treatment developmental times of pupae (i.e., degree days) that on average were 2.45–3-fold greater than of pupae reared at favorable temperatures. A lower developmental threshold and a facultative diapause increase the invasive potential of SATP in temperate areas. Knowledge of this thermal biology is essential for predicting the potential geographic spread of this pest and to develop management and control strategies.

Campos M.R., Béarez P., Amiens-Desneux E., Ponti L., Gutierrez A.P., Biondi A., Adiga A., Desneux N., 2020. Thermal biology of Tuta absoluta: demographic parameters and facultative diapause. Journal of Pest Science, https://doi.org/10.1007/s10340-020-01286-8 | Open Access

Percentage diapause (color legend) on temperatures (2 and 5 °C) and exposure times (days).


Comments

Post a Comment

Popular posts from this blog

Risk assessment for tiger mosquito in Europe

Image
The Asian tiger mosquito ( Ae. albopictus ) is indigenous to the oriental region, but is now widespread throughout the world. It is an aggressive mosquito, which causes nuisance and is well known vector of important human disease. It is one of the world’s most invasive species and is now invading Europe by both natural means and human assisted dispersal. Currently, there is no consensus on the limits of its potential geographic distribution in Europe. For this reason, studying the role that environmental driving variables, mainly temperature, play in determining the spatial variation of the potential population abundance of the mosquito should be considered a high priority. To assess the risk posed by Ae. albopictus to Europe, a lattice model based on the temperature-dependent physiologically based demographic modelling approach has been developed and is being tested against field observations. The area of potential distribution of this insect is simulated as driven by current climate
Read more

Impact of low temperature and host plant on Tuta absoluta

Image
Alternative host plants are among the key factors influencing the spread of invasive pests because they are utilized as a food source and provide shelter in unfavorable conditions. The South American tomato pinworm (SATP), Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), has a high behavioral and physiological plasticity enabling it to rapidly spread in several countries. Among the multiple strategies used by SATP in the invasion process is the use of alternative host plants including black nightshade (BNS), Solanum nigrum L. (Solanaceae), a perennial plant widely distributed across all habitats worldwide. Besides the life table and behavioral parameters of SATP on tomato, its survival and reproduction in low temperatures on alternative host plants should be assessed to evaluate the likely spread in temperate regions with harsh winters. In our study, comparing solanaceous species through generations, the primary difference was in the mean generation time with SATP reared on BNS, whe
Read more

Invasive potential of tropical fruit flies in temperate regions under climate change

Image
Tropical fruit flies are considered among the most economically important invasive species detected in temperate areas of the United States and the European Union. Detections often trigger quarantine and eradication programs that are conducted without a holistic understanding of the threat posed. Weather-driven physiologically-based demographic models are used to estimate the geographic range, relative abundance, and threat posed by four tropical tephritid fruit flies (Mediterranean fruit fly, melon fly, oriental fruit fly, and Mexican fruit fly) in North and Central America, and the European-Mediterranean region under extant and climate change weather (RCP8.5 and A1B scenarios). Most temperate areas under tropical fruit fly propagule pressure have not been suitable for establishment, but suitability is predicted to increase in some areas with climate change. To meet this ongoing challenge, investments are needed to collect sound biological data to develop mechanistic models to predict
Read more