Effects of temperature on instar number and larval development in the endangered longhorn beetle Callipogon relictus (Coleoptera: Cerambycidae) raised on an artificial diet

Abstract

Callipogon relictus Semenov (Coleoptera: Cerambycidae) is currently listed in the Red Data Books (Category I) of Russia and South Korea and, in 2006, was designated by the South Korean government as the first invertebrate priority target species in a restoration project. However, the species is also classified as an invasive quarantine pest by the Canadian Food Inspection Agency. Due to the five-year to seven-year life cycle of the species, experimental information about instar numbers has been poorly documented. Therefore, the goal of the present study was to document the instar numbers of non-diapause Callipogon relictus larvae reared on an artificial diet. Under conditions of 30 degrees C, 60% relative humidity, and constant dark (0:24 hour light-dark photoperiod), developmental pathways of 8, 10, and 12 instars were observed. The effect of temperature (20, 25, and 30 degrees C) on the duration of larval development was also examined to identify the optimum temperature for producing Callipogon relictus for conservational purposes. Larvae reared at 30 degrees C and 60% relative humidity, without a chill period, developed in seven to eight months, which is about one-tenth the duration of C. relictus development under natural conditions and the most rapid development of C. relictus observed to date.