The ladybug, Cryptolaemus montrouzieri (Mulsant) (Coleoptera: Cocccinellidae)(Mulsant)(Coleoptera: Cocccinellidae), is a highly efficient predator in controlling mealybug populations and is considered an effective agent for controlling the papaya mealybugs (Paracoccus marginatus) (Williams & Granara de Willink) (Hemiptera: Pseudococcidae). Various criteria have been proposed for evaluating predator effectiveness, with the consumption rate of prey by individual predators, specifically the functional response, emerging as a common and crucial metric. This study evaluated the functional responses of third- and fourth-instar larvae, as well as male and female adults (<48 h old) of C. montrouzieri to adult females of P. marginatus at 3 different temperatures (22 °C, 28 °C, and 35 °C) with 70% ± 5% RH and a 12L:12D h photoperiod. Prey densities were 2, 4, 8, 16, 32, 45, or 60 papaya mealybugs per predator for all tests. The response to prey density by third- and fourth-instar larvae or both sexes of adult C. montrouzieri was a type II at all temperatures. The highest attack rate and lowest handling time were estimated at 28 °C in males and 35 °C in females, respectively. The highest daily prey consumption rate occurred at 35 °C in both the immature and adult stages of C. montrouzieri. These findings support the potential of C. montrouzieri in controlling the papaya mealybug, especially in tropical and subtropical regions, given its search efficiency at high temperatures tested in this study. However, additional field investigations are needed to ascertain the control efficacy of C. montrouzieri for this mealybug in biocontrol programs.

UDP-N-acetylglucosamine pyrophosphorylase (UAP) is an essential enzyme in the insect chitin biosynthesis pathway; however, little is known regarding its molecular functions in Oedaleus asiaticus Bey-Bienko (Orthoptera: Acrididae). Here, two UAP genes, OaUAP1 and OaUAP2, were identified and characterized in O. asiaticus. The effects of exogenous treatments, including the molting hormone 20-hydroxyecdysone (20E) and the chitin biosynthesis inhibitor validamycin (VA), were assessed on chitin synthesis. Sequence analyses have shown that the cDNA and deduced amino acid sequences of O. asiaticus share over 90% identity with UAPs in Locusta migratoria. OaUAP1 and OaUAP2 are widely expressed in many tissues and developmental stages but exhibit different expression patterns: OaUAP1 shows higher expression in the epidermis and fifth-instar nymphs, while OaUAP2 is primarily expressed in the fat body and in the fifth-instar nymphs and adults. The functional analysis of two OaUAPs revealed that OaUAP2 was crucial in molting; moreover, its implication also exists in other biosynthetic processes since nymphs maintained normal growth and development. Both OaUAP expressions were upregulated by 20E and downregulated by VA in the chitin biosynthesis pathway. Our findings provide a vital molecular insight into the chitin biosynthesis pathway of O. asiaticus and lay a solid foundation for developing environmentally safe biological insecticides.