Assessing the lower thermal limits for development, fecundity, and survival in <em>Anisandrus maiche</em> (Kurentzov)

Anisandrus maiche is an emerging ambrosia beetle pest that attacks forest, ornamental, and fruit and nut trees, yet little is known about its developmental biology or thermal thresholds for reproduction. Characterizing thermal ranges for insect pests is critical for understanding range expansion, guiding management strategies, and building predictive models. Single female A. maiche were placed in artificial diet rearing tubes and allowed to develop for up to ten weeks at constant 10 °C, 14 °C, or 18 °C. No development occurred at 10 °C, although foundress females survived for up to eight weeks under these conditions. At 14 °C, only a single egg was recovered at five weeks, with no other developmental stages observed. Complete development occurred at 18 °C, with eggs appearing as early as two weeks post-introduction and all life stages appearing at eight weeks, indicating that some development occurs at 14 °C, whereas full development occurs somewhere between 14 °C and 18 °C. Results from this experiment define thermal minimums required for A. maiche development and reproduction. This information is the first step for understanding the developmental biology of A. maiche and can be used to support degree-day-based models and improve management timing for this emerging ambrosia beetle pest. Methods Single female Anisandrus maiche were placed in artificial diet rearing tubes and allowed to develop for up to ten weeks at constant 10 °C, 14 °C, or 18 °C. Three diet tubes were dissected twice per week to assess weekly development under constant temperatures. No development occurred at 10 °C, although foundress females survived for up to eight weeks under these conditions. At 14 °C, only a single egg was recovered at five weeks, with no other developmental stages observed. Complete development occurred at 18 °C, with eggs appearing as early as two weeks post-introduction and all life stages appearing at eight weeks, highlighting key thermal thresholds for reproduction and survival. Results from this experiment define thermal minimums required for A. maiche development and reproduction.