Cheyletus malaccensis Oudemans is a predatory mite inhabiting grain depots in China. The relationship between temperature and the population growth rate of C. malaccensis is useful for predicting its population dynamics. Age-stage, two-sex life tables of the predator, C. malaccensis, reared on Acarus siro were constructed under laboratory conditions at 22, 24, 28, 30, and 32 °C, 75% relative humidity, and a 0:24 h (L:D) photoperiod. Increasing temperature shortened the development time of the immature stages. The complete generation time of C. malaccensis ranged from 11.10 d to 27.50 d. Life table parameters showed that 28 °C was the optimum temperature for the growth and development of C. malaccensis; populations could increase rapidly at this temperature. The highest net reproductive rate (R0 = 290.25) and highest fecundity (544.52) occurred at 28 °C. Temperature significantly affected the intrinsic rate of increase (r), fecundity, and finite rate of increase (λ). The values of age-specific fecundity (high to low) were 28 °C > 24 °C > 30 °C > 32 °C > 22 °C, while the values of age-stage-specific fecundity had the same trend.

Carpophilus dimidiatus (Fabricius, 1792) and Carpophilus pilosellus Motschulsky are two sibling species and economically important storage pests worldwide. The first complete mitochondrial (mt) genomes of both were sequenced using next-generation sequencing. The mt genomes of C. dimidiatus and C. pilosellus are circular, with total lengths of 15,717 bp and 15,686 bp, respectively. Gene order and content for both species are similar to what has been observed in ancestral insects and consist of 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a control region. Comparing the mt genome data of C. dimidiatus and C. pilosellus, they are similar in organization, arrangement patterns, GC contents, transfer RNA (tRNA) secondary structures, and codon usage patterns. Small differences were noted with regards to the nucleotide similarity of coding regions and the control region. This is the first publication of the complete mitochondrial genomes of two sibling species. The mt genome sequences can supplement the nuclear markers of the Carpophilus genus in research species identification, system evolution, and population genetic structure, and also will be valuable molecular marker for further genetic studies.

Cheyletus malaccensis Oudemans and Cheyletus eruditus (Schrank) are predators of stored-grain pests in China. The psocid Liposcelis bostrychophila Badonnel is prone to outbreaks in depots. To assess the potential of large-scale breeding with Acarus siro Linnaeus and the biological control potential of C. malaccensis and C. eruditus against L. bostrychophila, we determined the development times of different stages at 16, 20, 24, and 28 °C and 75% relative humidity (RH) while feeding on A. siro, as well as the functional responses of both species’ protonymphs and females to L. bostrychophila eggs at 28 °C and 75% RH. Cheyletus malaccensis had a shorter development time and longer adult survival time than C. eruditus at 28 °C and 75% RH and could establish populations faster than C. eruditus while preying on A. siro. The protonymphs of both species showed a type II functional response, while the females showed a type III functional response. Cheyletus malaccensis showed a higher predation ability than C. eruditus, and the females of both species had a higher predation ability than the protonymphs. Based on the observed development times, adult survival times, and predation efficiency, Cheyletus malaccensis has much greater biocontrol potential than C. eruditus.

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The predatory mite Cheyletus malaccensis (Acari: Cheyletidae), commonly occurring in stores of various food commodities, is an important natural enemy of stored product pests. Disentangling the mt genome sequence of C. malaccensis at molecular level can decrease uncertainties during morphological identification and is useful in reconstructing the phylogeny of Acariformes group. In this study, the complete mitogenome of C. malaccensis was sequenced by the next-generation sequencing. After assembly and annotation, we found the circular 14,732 bp mitogenome of C. malaccensis, containing 13 protein coding genes, 2 ribosomal RNA (rRNA) genes and 22 transfer RNA (tRNA) genes. Compared with the ancestral mitogenome organization of arthropods, most of tRNA were truncated without D-arm or/and TψC-arm. Rearrangement was found in 12 mitogenome genes. Phylogenetic analyses based on the mitogenome data from other 29 mite species were inferred by Bayesian and maximum likelihood methods, which strongly supported the closer relationship between C. malaccensis and Tetranychidae than other mites. The obtained results represent the first complete mitochondrial genome record for Cheyletidae group. It may help improve molecular phylogenetic relationship and population genetics of the Cheyletidae.