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Background: Aphis gossypii (Hemiptera: Aphididae) is a worldwide polyphagous phloem-feeding agricultural pest, and it can produce offspring by sexual or asexual reproduction. Compared with dozens of generations by parthenogenesis, sexual reproduction is performed in only one generation within one year, and little is known about the sexual reproduction of A. gossypii. In this study, sexual females of A. gossypii were successfully obtained through a previously established induction platform, and the morphological characteristics, developmental dynamics, and temporal gene expression were examined. Subsequently, signaling pathways potentially involved in regulating the growth, development, and reproduction of sexual females were investigated. Results: The morphological observation showed that from the 1st instar nymph to adult, sexual females exhibited a gradually deepened body color, an enlarged body size, longer antennae with a blackened end, and obviously protruding cauda (in adulthood). The anatomy found that the ovaries of sexual females developed rapidly from the 2nd instar nymph, and the embedded oocytes matured in adulthood. In addition, time-course transcriptome analysis revealed that gene expression profiles across the development of sexual females fell into 9 clusters with distinct patterns, in which gene expression levels in clusters 1, 5, and 8 peaked at the 2nd instar nymphal stage with the largest number of up-regulated genes, suggesting that the 2nd instar nymph was an important ovary development period. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that a large number of genes in the sexual female adult were enriched in the TGF-beta signaling pathway and Forkhead box O (FoxO) signaling pathway, highlighting their important role in sexual female adult development and reproduction. Conclusion: The morphological changes of the sexual female at each developmental stage were revealed for the first time. In addition, time-course transcriptomic analyses suggest genes enriched in the TGF-beta signaling pathway and FoxO signaling pathway probably contribute to regulating the development and oocyte maturation of sexual females. Overall, these findings will facilitate the regulating mechanism research in the growth and development of sexual females by providing candidate genes. [ABSTRACT FROM AUTHOR]

Abstract Background Aphis gossypii (Hemiptera: Aphididae) is a worldwide polyphagous phloem-feeding agricultural pest, and it can produce offspring by sexual or asexual reproduction. Compared with dozens of generations by parthenogenesis, sexual reproduction is performed in only one generation within one year, and little is known about the sexual reproduction of A. gossypii. In this study, sexual females of A. gossypii were successfully obtained through a previously established induction platform, and the morphological characteristics, developmental dynamics, and temporal gene expression were examined. Subsequently, signaling pathways potentially involved in regulating the growth, development, and reproduction of sexual females were investigated. Results The morphological observation showed that from the 1st instar nymph to adult, sexual females exhibited a gradually deepened body color, an enlarged body size, longer antennae with a blackened end, and obviously protruding cauda (in adulthood). The anatomy found that the ovaries of sexual females developed rapidly from the 2nd instar nymph, and the embedded oocytes matured in adulthood. In addition, time-course transcriptome analysis revealed that gene expression profiles across the development of sexual females fell into 9 clusters with distinct patterns, in which gene expression levels in clusters 1, 5, and 8 peaked at the 2nd instar nymphal stage with the largest number of up-regulated genes, suggesting that the 2nd instar nymph was an important ovary development period. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that a large number of genes in the sexual female adult were enriched in the TGF-beta signaling pathway and Forkhead box O (FoxO) signaling pathway, highlighting their important role in sexual female adult development and reproduction. Conclusion The morphological changes of the sexual female at each developmental stage were revealed for the first time. In addition, time-course transcriptomic analyses suggest genes enriched in the TGF-beta signaling pathway and FoxO signaling pathway probably contribute to regulating the development and oocyte maturation of sexual females. Overall, these findings will facilitate the regulating mechanism research in the growth and development of sexual females by providing candidate genes.

Simple Summary: The host-alternating aphid Semiaphis heraclei (Hemiptera: Aphididae) is the dominant pest of its primary host plant—honeysuckle (Lonicera japonica). As the initial generation on honeysuckles each year, the sexual generation is a key target in aphid control. Understanding the mechanism underlying chemical communication between sexual aphids could be helpful for exploring olfactory stimulus-based male trapping techniques. In this study, the morphology of antennae and the types, sizes, numbers, and distribution of sensilla on the male and sexual female antennae of S. heraclei were investigated by means of scanning electron microscopy. The male antennae were dramatically longer than those of sexual females and the flagellum length contributed to the different antennal length between the two sexes. Four of five sensillum types or subtypes present in both sexes were enlarged in males. In addition, trichoid sensilla subtype I were more abundant on male antennae than on sexual female antennae. In particular, secondary rhinaria were found to be male specific. These sex-biased traits could be of great importance in the perception of sex pheromones. Our findings provide insight into the olfactory sensing mechanism of sexual individuals to assist in pest control. Sexual generation is an important generation in the life cycle of host-alternating aphids, and its population size determines the intensity of the peak in the next spring. Although male trapping techniques based on olfactory stimuli have been successfully established in the field, the biological basis of olfactory perception in males is unclear. In this study, we compared the morphology of antennae and the types, sizes, numbers, and distribution of sensilla between males and sexual females in the host-alternating aphid Semiaphis heraclei (Hemiptera: Aphididae). We found that flagellum length differentiation contributed to the majority of the sexual dimorphism of antennae. Most sensillum types or subtypes, including trichoid sensilla subtype I, campaniform sensilla, and primary rhinaria subtypes I and II, were enlarged in males. In addition, males bore more trichoid sensilla subtype I than sexual females. In particular, secondary rhinaria were present in males only and could not be detected in sexual females. These results revealed the structural basis of male olfactory perception. Our findings provide insight into the mechanism underlying chemical communication between sexual aphids and could thus be useful for pest control. [ABSTRACT FROM AUTHOR]

Sexual generation is an important generation in the life cycle of host-alternating aphids, and its population size determines the intensity of the peak in the next spring. Although male trapping techniques based on olfactory stimuli have been successfully established in the field, the biological basis of olfactory perception in males is unclear. In this study, we compared the morphology of antennae and the types, sizes, numbers, and distribution of sensilla between males and sexual females in the host-alternating aphid Semiaphis heraclei (Hemiptera: Aphididae). We found that flagellum length differentiation contributed to the majority of the sexual dimorphism of antennae. Most sensillum types or subtypes, including trichoid sensilla subtype I, campaniform sensilla, and primary rhinaria subtypes I and II, were enlarged in males. In addition, males bore more trichoid sensilla subtype I than sexual females. In particular, secondary rhinaria were present in males only and could not be detected in sexual females. These results revealed the structural basis of male olfactory perception. Our findings provide insight into the mechanism underlying chemical communication between sexual aphids and could thus be useful for pest control.

The study included the effect of two types of citrus in some aspects of the biology of the oriental spider mite Eutetranychus orientalis (Klein), lemon Citrus limon, Var. Mahali and grapefruit Citrus paradisi, var. Duncan at temperature (25 ± 2°C), relative humidity (50-60%) and 12-hour light duration to 12 hours of darkness at the graduate insect laboratory at the college of Agricultural Engineering Sciences/University of Baghdad. Results showed that the food preference of the host species had a direct effect on the growth period of the immature stages of the oriental spider mite survival rate when arise on those species, it recorded the shortest period of egg incubation and larval and nymph development and life cycle and highest survival rate for spider mite stages arise on lemon were recorded 4.03 days, 6.97 days, 11.00 days and 65.97%, respectively. While, the longest duration of egg incubation, larval and nymph development and the lowest survival rate of spider mite stages arise on grapefruit were 4.93 days, 7.96 days, 12.89 days and 57.60%, respectively. The biological and reproductive parameters of the spider mite adults were arise on the lemons and grapefruit. It recorded the longest age of female and male adults, the shortest pre-egg laying period, the longest duration of egg laying and post egg laying and the largest total egg and the number of eggs per day, the largest percentage of egg hatch, the shortest length of the generation and the highest percentage of sexual adult eggs grown on lemons with 13.4, 8.0, 1.67, 8.2, 3.53 days, 39.09, 4.77 eggs, 69.5%, 12.63 days and 1.3:3 respectively. Whereas, It recorded the shortest age of female and male adults, the longest pre-egg laying period, the shorter duration of egg laying and post egg laying and the smallest total egg and the number of eggs per day, the smallest percentage of egg hatch, the longest length of the generation and the lowest percentage of sexual adult eggs grown on lemons with 12.23, 7.33, 1.87, 7.37, 3.0 days, 29.46, 4.0 eggs, 64.3%, 14.76 days and 1: 2 respectively. Thus, sour lemon is the most preferred and appropriate to nourish the oriental spider mite and its growth and development than of grapefruit. [ABSTRACT FROM AUTHOR]

Moina micrura is a kind of small-bodied water flea within the family Moinidae. Similar to Daphnia, M. micrura could also switch its reproduction mode from parthenogenetic female (PF) to sexual female (SF) to adapt to the external environment. To uncover the mechanisms of reproductive switching in M. micrura, we used both RNA-Seq and iTRAQ analyses to investigate the differentially expressed genes (DEGs) and their protein products between SF and PF in M. micrura. A total of 1665 DEGs (702 up-regulated, 963 down-regulated) and 600 differentially expressed proteins (DEPs) (102 up-regulated, 498 down-regulated) were detected in SF. Correlation analyses indicated that 31 genes were expressed significantly differentially at both transcriptomic and proteomic levels, including 15 up-regulated genes and 16 down-regulated genes in SF. Meanwhile, our data also showed that 528 DEPs have discordant expression at transcript level, implying post-transcriptional (including translational) regulation. These top up-regulated genes and their protein products in SF were mainly grouped into the globin-related family, vitellogenin-related family, cuticle-related family, Hsp-related family and methyltransferases-related family, which were all involved in the reproductive switching in Daphnia. In contrast, a cluster of orthologous groups revealed that up-regulated genes and their protein products in PF were strongly associated with the metabolic process, which may be responsible for rapid population proliferation in M. micrura.

Moina micrura is a kind of small-bodied water flea within the family Moinidae. Similar to Daphnia, M. micrura could also switch its reproduction mode from parthenogenetic female (PF) to sexual female (SF) to adapt to the external environment. To uncover the mechanisms of reproductive switching in M. micrura, we used both RNA-Seq and iTRAQ analyses to investigate the differentially expressed genes (DEGs) and their protein products between SF and PF in M. micrura. A total of 1665 DEGs (702 up-regulated, 963 down-regulated) and 600 differentially expressed proteins (DEPs) (102 up-regulated, 498 down-regulated) were detected in SF. Correlation analyses indicated that 31 genes were expressed significantly differentially at both transcriptomic and proteomic levels, including 15 up-regulated genes and 16 down-regulated genes in SF. Meanwhile, our data also showed that 528 DEPs have discordant expression at transcript level, implying post-transcriptional (including translational) regulation. These top up-regulated genes and their protein products in SF were mainly grouped into the globin-related family, vitellogenin-related family, cuticle-related family, Hsp-related family and methyltransferases-related family, which were all involved in the reproductive switching in Daphnia. In contrast, a cluster of orthologous groups revealed that up-regulated genes and their protein products in PF were strongly associated with the metabolic process, which may be responsible for rapid population proliferation in M. micrura. [ABSTRACT FROM AUTHOR]

Moina micrura is a kind of small-bodied water flea within the family Moinidae. Similar to Daphnia , M. micrura could also switch its reproduction mode from parthenogenetic female (PF) to sexual female (SF) to adapt to the external environment. To uncover the mechanisms of reproductive switching in M. micrura , we used both RNA-Seq and iTRAQ analyses to investigate the differentially expressed genes (DEGs) and their protein products between SF and PF in M. micrura . A total of 1665 DEGs (702 up-regulated, 963 down-regulated) and 600 differentially expressed proteins (DEPs) (102 up-regulated, 498 down-regulated) were detected in SF. Correlation analyses indicated that 31 genes were expressed significantly differentially at both transcriptomic and proteomic levels, including 15 up-regulated genes and 16 down-regulated genes in SF. Meanwhile, our data also showed that 528 DEPs have discordant expression at transcript level, implying post-transcriptional (including translational) regulation. These top up-regulated genes and their protein products in SF were mainly grouped into the globin-related family, vitellogenin-related family, cuticle-related family, Hsp-related family and methyltransferases-related family, which were all involved in the reproductive switching in Daphnia . In contrast, a cluster of orthologous groups revealed that up-regulated genes and their protein products in PF were strongly associated with the metabolic process, which may be responsible for rapid population proliferation in M. micrura .