Integrating Temperature-Dependent Life Table Data into a Matrix Projection Model for Drosophila suzukii Population Estimation

Abstract

Temperature-dependent fecundity and survival data was integrated into a matrix population model to describe relative Drosophila suzukii Matsumura (Diptera: Drosophilidae) population increase and age structure based on environmental conditions. This novel modification of the classic Leslie matrix population model is presented as a way to examine how insect populations interact with the environment, and has application as a predictor of population density. For D. suzukii, we examined model implications for pest pressure on crops. As case studies, we examined model predictions in three small fruit production regions in the United States (US) and one in Italy. These production regions have distinctly different climates. In general, patterns of adult D. suzukii trap activity broadly mimicked seasonal population levels predicted by the model using only temperature data. Age structure of estimated populations suggest that trap and fruit infestation data are of limited value and are insufficient for model validation. Thus, we suggest alternative experiments for validation. The model is advantageous in that it provides stage-specific population estimation, which can potentially guide management strategies and provide unique opportunities to simulate stage-specific management effects such as insecticide applications or the effect of biological control on a specific life-stage. The two factors that drive initiation of the model are suitable temperatures (biofix) and availability of a suitable host medium (fruit). Although there are many factors affecting population dynamics of D. suzukii in the field, temperature-dependent survival and reproduction are believed to be the main drivers for D. suzukii populations.

Economic Impact of the Introduction and Establishment of Drosophila suzukii on Sweet Cherry Production in Switzerland

“…While adult captures are only a poor indicator of actual crop infestation risk [22] and thus do not replace the more laborious fruit checks, traps provide early warning of fly activity and insight into the temporal variation of D. suzukii population dynamics. Ongoing research efforts towards developing modelling tools that describe and forecast D. suzukii populations will improve future management practices by predicting pest pressure independent of trap captures and samples of infested fruit [1,23,24]. In the meantime, however, the surveillance measures currently in use remain the key to a more appropriate scheduling of control measures, in particular to more rational insecticide use strategies.…”

Invasion biology of spotted wing Drosophila (Drosophila suzukii): a global perspective and future priorities

“…In this section, we review two demographic models for SWD: a stage-specific Leslie-matrix model , and a distributed maturation time, physiologically based demographic model (PBDM) in a GIS context (Gutierrez, Plantamp, and Ponti, see Supplemental Material). Wiman et al (2014) used a degree-day approach for time and age within a Leslie-matrix modeling structure. The model is based on temperature-dependent developmental, survival, and fecundity data from Tochen et al (2014).…”

“…Asplen, personal observation). More importantly, it suggests that older SWD populations may be better able to maintain relatively high pest pressures on susceptible fruit than other drosophilids Wiman et al 2014). …”

“…Despite isolated early reports of SWD-related damage in Asia (Kanzawa 1939;Tan et al 1949), first reports of the pest in North America and Europe date back only to the late 2000s (see below), followed by rapid range expansion within these continents. This leaves many unanswered questions related to putative invasion corridors and dispersal modes, thermal constraints on SWD biology, and the absence of effective levels of natural biological control in the invaded regions (Cini et al 2014;Wiman et al 2014).…”

An invader supported by a parasite: Mistletoe berries as a host for food and reproduction of Spotted Wing Drosophila in early spring

“…In temperate climates, SWD is a winter-active species when mean temperatures allow flight activity. Although exact data on temperature-dependent flight are not available, seasonal catches from diverse regions during winter indicate that flight activity seems to be still possible when mean daily temperatures are around 5°C (Harris et al 2014;Wiman et al 2014;Briem et al 2015;Shearer, pers. communication).…”