The life table of the green lacewing, Chrysopa pallens (Rambur), was studied at 22°C, a photoperiod of 15:9 (L:D) h, and 80% relative humidity in the laboratory

Background: The interactions of fig wasps and their host figs provide a model for investigating co-evolution. Fig wasps have specialized morphological characters and lifestyles thought to be adaptations to living in the fig's syconium. Although these aspects of natural history are well documented, the genetic mechanism(s) underlying these changes remain(s) unknown. Fig wasp olfaction is the key to host-specificity. TheOr83bgene class, an unusual member of olfactory receptor family, plays a critical role in enabling the function of conventional olfactory receptors. FourOr83borthologous genes from one pollinator (PFW) (Ceratosolen solmsi) and three non-pollinator fig wasps (NPFWs) (Apocrypta bakeri, Philotrypesis pilosaandPhilotrypesissp.) associated with one species of fig (Ficus hispida) can be used to better understand the molecular mechanism underlying the fig wasp's adaptation to its host. We made a comparison of spatial tissue-specific expression patterns and substitution rates of one orthologous gene in these fig wasps and sought evidence for selection pressures.Results: A newly identifiedOr83borthologous gene was namedOr2. Expressions ofOr2were restricted to the heads of all wingless male fig wasps, which usually live in the dark cavity of a fig throughout their life cycle. However, expressions were widely detected in the antennae, legs and abdomens of all female fig wasps that fly from one fig to another for oviposition, and secondarily pollination. Weak expression was also observed in the thorax of PFWs. Compared with NPFWs, theOr2gene inC. solmsihad an elevated rate of substitutions and lower codon usage. Analyses using Tajima'sD, Fu and Li'sD*andF*tests indicated a non-neutral pattern of nucleotide variation in all fig wasps. Unlike in NPFWs, this non-neutral pattern was also observed for synonymous sites ofOr2within PFWs.Conclusion: The sex- and species-specific expression patterns ofOr2genes detected beyond the known primary olfactory tissues indicates the location of cryptic olfactory inputs. The specialized ecological niche of these wasps explains the unique habits and adaptive evolution ofOr2genes. TheOr2gene inC. solmsiis evolving very rapidly. Negative deviation from the neutral model of evolution reflects possible selection pressures acting onOr2sequences of fig wasp, particularly on PFWs who are more host-specific to figs.

Chrysoperla nipponensis (Okamoto), which has the unique diapause phenotype distinguishable from nondiapause adult, is an ideal model organism for studying the mechanism of reproductive diapause. However, there is no reliable and effective reference genes used for the reproductive diapause study of C. nipponensis. Therefore, in this study, we evaluated the expression stability of 10 candidate reference genes (Tub1, Arpc5, EF1a, 128up, RpS5, RpS26e, GAPDH, Arp3, Actin, α-Tub) in adults under diapause and nondiapause induction conditions using four statistical algorithms including GeNorm, NormFinder, Bestkeeper, and ∆CT method. Results showed that Arp3 and Tub1 were the most stable reference genes in all samples and in the adult tissues group. Arp3 and RpS5 were the most stable reference genes in the development degree group. α-Tub and EF1a were unstable reference genes under the conditions of this study. Meanwhile, to verify the reliability of the reference genes, we evaluated the relative expression levels of Vg and VgR in different treatments. Significant upregulation and downregulation in expression level of two genes in response to diapause termination and diapause fat body tissue was, respectively, observed when using Arp3 as the reference gene but not when using an unstable reference gene. The reference genes identified in this work provided not only the basis for future functional genomics research in diapause of C. nipponensis and will also identify reliable normalization factors for real-time quantitative real-time polymerase chain reaction data for other related insects.

The oriental fruit moth, Grapholita molesta, is an important pest in many commercial orchards including apple, pear and peach orchards, and responsible for substantial economic losses every year. To help in attaining a comprehensive and thorough understanding of the ecological tolerances of G. molesta, we collected life history data of individuals reared on apples under different constant temperature regimes and compared the data with moths reared under a variable outdoor temperature environment. Because G. molesta individuals reared at a constant 25°C had the heaviest pupal weight, the highest survival rate from egg to adult, highest finite rate of increase, and greatest fecundity, 25°C was considered as the optimum developmental temperature. The G. molesta population reared at a constant 31°C had the shortest development time, lowest survival rate and fecundity, resulting in population parameters of r < 0, λ < 1, lead to negative population growth. The population parameters r and λ reared under fluctuating temperature were higher than that reared under constant temperatures, the mean generation time (T) was shorter than it was in all of the constant temperatures treatments. This would imply that the outdoor G. molesta population would have a higher population growth potential and faster growth rate than indoor populations raised at constant temperatures. G. molesta moths reared under fluctuating temperature also had a higher fertility than moths reared under constant temperatures (except at 25°C). Our findings indicated that the population raised under outdoor fluctuating temperature conditions had strong environment adaptiveness.

In insects, neuropeptides and their receptors not only play a critical role in insect physiology and behavior but also are the potential targets for novel pesticide discoveries. Aphidius gifuensis is one of the most important and widespread aphid parasitoids, and has been successfully used to control aphid. In the present work, we systematically identified neuropeptides and their receptors from the genome and head transcriptome of A. gifuensis. A total of 35 neuropeptide precursors and 49 corresponding receptors were identified. The phylogenetic analyses demonstrated that 35 of these receptors belong to family-A, four belong to family-B, two belong to leucine-rich repeat-containing GPCRs, four belong to receptor guanylyl cyclases, and four belong to receptor tyrosine kinases. Oral ingestion of imidacloprid significantly up-regulated five neuropeptide precursors and four receptors whereas three neuropeptide precursors and eight receptors were significantly down-regulated, which indicated that these neuropeptides and their receptors are potential targets of some commercial insecticides. The RT-qPCR results showed that dopamine receptor 1, dopamine receptor 2, octopamine receptor, allatostatin-A receptor, neuropeptides capa receptor, SIFamide receptor, FMRFamide receptor, tyramine receptor and short neuropeptide F predominantly were expressed in the head whilst the expression of ion transport peptide showed widespread distribution in various tissues. The high expression levels of these genes suggest their important roles in the central nervous system. Taken together, our study provides fundamental information that may further our understanding of neuropeptidergic signaling systems in the regulation of the physiology and behavior of solitary wasps. Furthermore, this information could also aid in the design and discovery of specific and environment-friendly insecticides.

Serangium japonicum Chapin (Coleoptera: Coccinellidae) is a predominant predator with a preference for Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). To date, the orientational behavior of S. japonicum toward B. tabaci-infested plants has seldom been reported. In this study, greenhouse cage experiments and bioassays with wind tunnels, a Y-tube olfactometer and B. tabaci-induced plant volatiles were executed to clarify this behavior. In greenhouse cage experiments, B. tabaci adults significantly preferred eggplant, cucumber and tobacco to cotton and tomato, whereas S. japonicum adults preferred B. tabaci-infested eggplant, cucumber and cotton to tobacco and tomato. In wind tunnel bioassays, B. tabaci showed a clear preference for eggplant, cucumber and tobacco. Compared with B. tabaci-infested eggplant, cucumber or cotton, B. tabaci-infested tobacco was rarely visited by S. japonicum. In Y-tube bioassays, S. japonicum did not distinguish between B. tabaci-infested and uninfested eggplant. Nine common plant volatiles were detected in different plant species, suggesting that these volatiles may play an important role in the process by which S. japonicum looks for prey. In light of the current results, we discuss the implications of our findings and put forward to a new strategy—i.e., an eggplant + B. tabaci + S. japonicum system—to control B. tabaci damage in the integrated management of whitefly.