Nuclear receptors (NRs), which are typical transcription factors, are proteins found in all living organisms that enable responses to internal developmental processes or external environmental stimuli by controlling the transcription of different molecular networks [1,2]. In insects, NRs sense and respond to ecdysone titer. After an insect ingests food, a series of catalyzed reactions and unknown reactions termed the “black box” to synthesis and conversion the ecdysone to activate 20-hydroxyecdysone (20E) [3,4]. The 20E signaling pathway is activated when it binds to the ecdysone receptor complex, which is a heterodimer consisting of ultraspiracle (USP) and ecdysone receptor protein (EcR) [5]. The ecdysone receptor complex binds to the ecdysone response elements with high affinity by as transcription factors and then activates the expression of “early genes” such as E75, Br-C, and E74 [6]. The “early genes” products were trigger the differential expression of the downstream “early-late genes” such as HR4, HR3, and HR38 [6,7]. Then, the expression of these components co-interact including the “late genes” FTZ-F1. For example, the protein products of E75 and HR3 coordinate to regulate the expression levels of FTZ-F1 [8].

Numerous NR genes have been identified in many insect species. For example, the 21 NRs were identified in Tribolium castaneum [9], Drosophila melanogaster [10] and Bactrocera dorsalis [11], 20 in Bemisia tabaci [12] and Aedes aegypti [13] and 19 in Acyrthosiphon pisum [14], Bombyx mori [15] and Spodoptera litura [16]. Based on phylogenetic analysis and sequence similarity, the NRs were divided into seven subfamilies: NR0, NR1, NR2, NR3, NR4, NR5 and NR6 [8,10]. All of the predicted NR proteins contain a conserved ligand-binding domain (LBD) and zinc finger DNA-binding domain (DBD) [17]. As ligand-regulated transcription factors in insects, NRs have diverse important functions during growth and development. For example, RNA interference (RNAi)-mediated knockdown of NRs causes molting defects in Locusta migratoria [[18], [19], [20]], Besimia tabaci [12], Sitobion avenae [21] and Leptinotarsa decemlineata [22]. Mutation of USP in D. melanogaster delayed developmental timing and reduced body size [23]. In T. castaneum, seven NRs (HR3, E75, USP, EcR, FTZ-F1, HR4 and SVP) are critical for oogenesis and vitellogenesis, and seven other NRs (HR51, HR96, HR39, HR38, TLL, KNI-like and DSF) are required for embryogenesis [9]. In Rhodnius prolixus, suppressing the expression of FTZ-F1, E74, and E75 can impair egg production and hatchability [24]. In D. melanogaster, RNAi and genetic rescue experiments revealed that HR39 regulates male reproduction by influencing the expression of key fertility genes in the accessory glands [25]. HR83 was associated with resistance to chlorpyrifos in Nilaparvata lugens [26] and FTZ-F1, EcR, DSF and HR3 genes are involved in Spodoptera litura tolerance to flavone and xanthotoxin [16]. NRs also play critical roles in regulating the immune response [27,28], sex pheromone–oriented flight [29,30] and circadian rhythm [31].

The cigarette beetle, Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae), is a destructive pest of stored products. It causes substantial damage to stored grain, herbarium specimens, plants used in traditional Chinese herbal medicine and dry tobacco leaves [[32], [33], [34]]. Control of L. serricorne mainly relies on using fumigation with pesticides such as phosphine and by application of pyrethroids [35,36]. Due to toxic insecticide residues and the development of insecticide resistance in L. serricorne, alternative control strategies are needed. Previous studies indicated that decreasing the expression of HR3 and FTZ-F1 disrupted the larval metamorphosis of L. serricorne and suggested that this approach might lead to the development of pest control products [37,38]. However, a systematic functional analysis of NR genes in L. serricorne has not been completed. In this study, we report: (1) the cDNAs of 16 transcripts that are potential homologues of nuclear receptors in L. serricorne, (2) the expression patterns of NR genes in temporal and spatial, (3) the functional analysis of NR genes by RNAi in larva–pupa–adult transitions, and (4) the knockdown effects of NR genes on 20E synthesis, cuticle formation and chitin metabolism. These genes could be molecular targets for the RNAi-based control of L. serricorne.