Philippine Journal of Science
148 (1): 87-93, March 2019
ISSN 0031 – 7683
Date Received: 07 Aug 2018

Sotero S. Resilva1*, Brian N. Barnes2, and Glenda B. Obra1

*Corresponding author: ssresilva@yahoo.com

 

ABSTRACT

Pupal age is critical when sterilizing pupae of a different strain of Mediterranean fruit fly, Ceratitis capitata (Wiedemann), for a sterile insect technique (SIT) program. Pupal age is usually determined using pupal eye color, which is optimally dark brown for C. capitata prior to sterilizization. This color is achieved at 9 days of pupal age, 2 days before adult emergence, and upon maturity at 25 ºC. However, it is often necessary to use different pupal holding temperatures in order to manipulate pupal development, especially when unforeseen problems occur during the C. capitata rearing procedure. Holding pupae at lower temperatures delays pupal development and slows down the progression of eye color changes; at higher temperatures, the opposite occurs. The pupal eye color of C. capitata was documented at different ages at different holding temperatures. When maturing pupae at 17, 20, 25 (standard holding temperature), and 28 ºC, the developmental duration of pupae was 28, 17, 11, and 9 days, respectively. Using this eye color as the reference guide for timing the irradiation of pupae, the optimum pupal age for irradiation when held at 17, 19, and 28 ºC was 23–26, 14–15, and 8 days old, respectively. Documented and close-up photographs of pupal eye color for different pupal holding temperatures are presented here can be used as a reference guide to determine the best time for the irradiation of pupae in an SIT program.