Effects of supplemental nutrients on ovarian development and oviposition in Conogethes punctiferalis (Lepidoptera: Crambidae).

Conogethes punctiferalis is a serious pest in China affecting a wide variety of field crops, fruits, and forest trees. Many insects require supplemental nutrients after emergence to compensate for insufficient nutrients at the larval stage. In this study, to better understand the determinants of C. punctiferalis survival and reproduction, the impact of supplemental nutrition was examined. In particular, the effects of 11 treatments (5% sucrose, 10% sucrose, 15% sucrose, 5% sophora honey, 10% sophora honey, 15% sophora honey, 5% wild honey, 10% wild honey, 15% wild honey, distilled water, and blank control) on adult longevity and oviposition were evaluated, with detailed morphological analyses of ovarian development in the 10% sucrose, distilled water, and blank control groups. Conogethes punctiferalis required supplementary nutrition after emergence. Supplementary nutrition improved fecundity (number of eggs laid) and longevity, and 10% sucrose water had the greatest effects. The preoviposition period and oviposition period of C. punctiferalis females were longer, and the numbers of eggs in female ovarian tubes and eggs laid by females were higher in the 10% sucrose water group than in other groups. Females supplemented with distilled water laid a small number of eggs. Without nutrient supplementation, females did not lay eggs. In conclusion, supplemental nutrition was beneficial for ovarian development in female moths, prolonging the oviposition period and lifespan, and was an important factor affecting population dynamics. These results lay a foundation for further analyses of the nutritional requirements for C. punctiferalis in the field and provide a reference for indoor population feeding.

Maternal genetic history of ancient Tibetans over the past 4,000 years.

The settlement of the Tibetan Plateau epitomizes human adaptation to a high-altitude environment that poses great challenges to human activity. Here, we reconstruct a 4,000-year maternal genetic history of Tibetans using 128 ancient mitochondrial genome data from 37 sites in Tibet. The phylogeny of haplotypes M9a1a, M9a1b, D4g2, G2a'c, and D4i show that ancient Tibetans shared the most recent common ancestor (TMRCA) with ancient Middle and Upper Yellow River populations around the Early and Middle Holocene. In addition, the connections between Tibetans and Northeastern Asians varied over the past 4,000 years, with a stronger matrilineal connection between the two during 4,000-3,000 BP, and a weakened connection after 3,000 BP, that were coincident with climate change, followed by a reinforced connection after the Tubo period (1,400-1,100 BP). Besides, an over 4,000-year matrilineal continuity was observed in some of the maternal lineages. We also found the maternal genetic structure of ancient Tibetans was correlated to the geography and interactions between ancient Tibetans and ancient Nepal and Pakistan populations. Overall, the maternal genetic history of Tibetans can be characterized as a long-term matrilineal continuity with frequent internal and external population interactions that were dynamically shaped by geography, climate changes, as well as historical events.

Morphologic Characters of the Rostrum in Two Weevils, Eucryptorrhynchus scrobiculatus Motschulsky and E. brandti Harold (Coleoptera: Curculionidae: Cryptorrhychinae).

(1) Eucryptorrhynchus scrobiculatus and E. brandti (Coleoptera: Curculionidae: Cryptorrhychinae) are both pests of Ailanthus altissima, found in China. During ovipositing, gravid females of the two weevils need to excavate a cavity in the oviposition substrate with their rostrum, while their oviposition sites are different. (2) In this study, to explore the boring mechanism of E. scrobiculatus and E. brandti during ovipositing, the morphologic characters of the rostra of two weevils were studied in detail by scanning electron microscopy and micro-CT. (3) Their rostra appear similar, but the rostrum surface of E. scrobiculatus is rougher than that of E. brandti; their fine structures of rostrum and sensilla distribution are similar, but the sensilla twig basiconica 3 is distributed at the apex of labial palpus in E. brandti females, while not at the apex of labial palpus in E. scrobiculatus females; their rostra are hollow and their cuticle thickness is constantly changing, but the proportion of the whole rostrum tube cuticle in E. scrobiculatus is significantly larger than that of E. brandti. The above structural differences make E. scrobiculatus more conducive to oviposition in the soil and E. brandti more conducive to oviposition in the trunk of A. altissima. (4) Overall, this study not only plays an important role in exploring the excavating mechanism during the oviposition of the two weevils, but also provides new insights into the coexistence of two weevil species on the same host A. altissima.

Ancient Mitogenomes Reveal the Origins and Genetic Structure of the Neolithic Shimao Population in Northern China.

Shimao City is considered an important political and religious center during the Late Neolithic Longshan period of the Middle Yellow River basin. The genetic history and population dynamics among the Shimao and other ancient populations, especially the Taosi-related populations, remain unknown. Here, we sequenced 172 complete mitochondrial genomes, ranging from the Yangshao to Longshan period, from individuals related to the Shimao culture in northern Shaanxi Province and Taosi culture in southern Shanxi Province, Middle Yellow River basin. Our results show that the populations inhabiting Shimao City had close genetic connections with an earlier population in the Middle Neolithic Yangshao period of northern Shaanxi Province, revealing a mostly local origin for the Shimao Society. In addition, among the populations in other regions of the Yellow River basin, the Shimao-related populations had the closest maternal affinity with the contemporaneous Taosi populations from the Longshan period. The Shimao-related populations also shared more affinity with present-day northern Han populations than with the minorities and southern Han in China. Our study provides a new perspective on the genetic origins and structure of the Shimao people and the population dynamics in the Middle Yellow River basin during the Neolithic period.

Structural comparison of the rostra of two species of weevils coexisting on Ailanthus altissima: the response to ecological demands of egg deposition.

BACKGROUND: Elongated rostra play an important role in the egg-laying of weevils, and its emergence plays a key role in the adaptive radiation of weevils. Eucryptorrhynchus scrobiculatus Motschulsky and E. brandti Harold co-occur on the same only host Ailanthus altissima, while their oviposition sites are different. In order to understand the adaptation between the rostra of the two weevils and their oviposition sites, the structural differentiation of the rostra in E. scrobiculatus and E. brandti was compared. RESULTS: The present study reveals that: (1) The rostra length of E. scrobiculatus and E. brandti was found to be correlated with body size, larger weevils have a correspondingly longer rostrum. The increase of rostra length may be a byproduct of larger weevils. (2) There were significant differences in the external shape of the two rostra, especially the shape of the mandibles of the mouthparts at the apex of the rostra used to excavate an oviposition cavity. (3) There was no difference in the size of the abductor muscles that control the extension of the mandibles, but there were significant differences in the size of the adductor muscles that control the contraction of the mandibles. CONCLUSIONS: These structural differences reflect the functional potential ovipositional tactics of rostra, which is considered to be a response to the ecological demands of egg deposition, and also provide new insights into the coexistence of two weevil species in the same host A. altissima.

Neurochemical regulation of Aedes aegypti salivary gland function.

The salivary gland of hematophagous arthropods is critical for blood meal acquisition, blood vessel localization, and secretion of digestive enzymes. Thus, there is significant interest in the regulation of salivary gland function and mechanisms driving the secretion of saliva and digestive proteins. We aimed to gain a broader understanding of the regulatory role of aminergic, cholinergic, and octopaminergic neuromodulators to saliva and protein secretion from the female A. aegypti salivary gland. Quantification of saliva after injection with neuromodulators showed that dopamine, serotonin, and pilocarpine increased the secretory activity of the salivary gland with potency rankings dopamine = serotonin > pilocarpine. No change in saliva secretion was observed with octopamine or ergonovine, which indicates the A. aegypti salivary gland may be regulated by dopaminergic, serotonergic, and cholinergic systems, but are not likely regulated by octopaminergic or tryptaminergic systems. Next, we studied the regulatory control of dopamine-mediated salivation. Data indicate extracellular calcium flux, but not neural function, is critical for dopamine-mediated salivation, which suggests epithelial transport of ions and not neuronal control is responsible for dopamine-mediated salivation. For regulation of protein secretion, data indicate dopamine or serotonin exposure facilitates amylase secretion, whereas serotonin but not dopamine exposure increased apyrase concentrations in the secreted saliva. General immunoreactivity to anti-rat D1-dopamine receptor antibody was observed, yet immunoreactivity to the anti-rat D2-receptor antibody was identified in the proximal regions of the lateral lobes and slight immunoreactivity in the distal portion of the lateral lobe, with no expression in the medial lobe.

Oviposition Behavior and Distribution of Eucryptorrhynchus scrobiculatus and E. brandti (Coleoptera: Curculionidae) on Ailanthus altissima (Mill.).

(1) Eucryptorrhynchus scrobiculatus Motschulsky (Coleoptera: Curculionidae: Cryptorrhychinae) is a major quarantine forest pest in China. It often co-occurs with E. brandti (Coleoptera: Curculionidae: Cryptorrhychinae) on a single host Ailanthus altissima (Mill.) Swingle (tree of heaven). (2) In this study, to explain the coexistence of the two weevils on a single host, we investigated the oviposition behavior of E. scrobiculatus and oviposition sites of E. scrobiculatus and E. brandti under afield and laboratory conditions. (3) The characteristic behaviors of E. scrobiculatus females prior to oviposition included searching, locating, excavation, turning, locating the oviposition cavity, egg deposition, and hiding. (4) The oviposition sites used by E. scrobiculatus and E. brandti differed. Eucryptorrhynchus scrobiculatus females laid eggs in the soil near A. altissima and compound leaf petioles, while E. brandti females laid eggs in A. altissima trunks. The eggs in compound leaf petioles did not hatch in the field. (5) Eucryptorrhynchus scrobiculatus and E. brandti utilized different oviposition sites and these differences in habitat use may reduce the competition for resources between species during the larval period, thus facilitating their coexistence on A. altissima.

Effects of Trap Color and Shape on the Capture of Eucryptorrhynchus scrobiculatus (Coleoptera: Curculionidae).

Eucryptorrhynchus scrobiculatus (Coleoptera:Curculionidae) is an important pest in China that specifically damages Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae). Trembler grid lamps and food attractant traps frequently were used to monitor and control E. scrobiculatus; however, the effect of these methods is poor in actual application. The purpose of this study was to develop a new monitoring method. Traps of seven colors and two shapes were compared with respect to the attraction of E. scrobiculatus adults, and a field trapping test was performed. We found that E. scrobiculatus adults were most sensitive to red (16.11 ± 7.72) and black traps (14.44 ± 8.07) and to tall vertical black shapes in the laboratory. In the field, red (70.50 ± 5.74) and black traps (60.75 ± 8.22) were most effective at catching E. scrobiculatus, and traps with color and attractant still were more attractive to E. scrobiculatus than traps with colors only. These results provide a reference for monitoring E. scrobiculatus adults.

Supplementary Nutrition of Eucryptorrhynchus brandti (Coleoptera: Curculionidae: Cryptorrhychinae): Effect of Ailanthus altissima Host Tissues on Ovary Maturation and Oviposition.

Eucryptorrhynchus brandti is a trunk-boring pest that causes severe damage to its single host, Ailanthus altissima in China. Eucryptorrhynchus brandti adults require supplementary nutrition to achieve sexual maturity. Adults feed on petioles, shoots, 2- to 3-yr-old branches, and stems of A. altissima, but prefer to feed on stems. The effects of different host plant tissues on ovary development and oviposition in E. brandti are unclear. Thus, we examined the effects of the consumption of A. altissima petioles, shoots, branches, and stems on ovary development of E. brandti. Using ovaries of different ages, we also evaluated the differentiation of ovarioles, presence and appearance of follicular relics, number of eggs, cuticle hardness, and fat body quantity over time. We found the reproductive system was composed of two ovaries, lateral oviducts, a common oviduct, and spermatheca. The physiological age of ovaries was divided into three nulliparous and three parous stages. Females fed on stems had mature ovaries and successfully oviposited; females fed on other tree tissues or water had no functional ovaries and did not lay eggs. We found virgin females must obtain sufficient nutrition, as evidenced by the immature ovaries in females fed the water. We also found that only stems of A. altissima contribute to egg development; however, the other tree tissues do not contribute to egg development. These findings improve our understanding of the feeding preference of E. brandti from the perspective of ovary development as well as optimal host tissues for ovary development.

Projecting potential distribution of Eucryptorrhynchus scrobiculatus Motschulsky and E. brandti (Harold) under historical climate and RCP 8.5 scenario.

Ailanthus altissima (Mill.) Swingle and its variant A. altissima var. Qiantouchun are notorious invasive weeds. Two weevils, Eucryptorrhynchus scrobiculatus (ESC) and E. brandti (EBR) are considered as candidates for biological control of A. altissima. The aim of this study was to model the potential distributions of ESC and EBR using CLIMEX 4.0. The projected potential distributions of ESC and EBR included almost all current distribution areas of A. altissima, except Southeast Asia. Under historical climate, potential distribution area of EBR is larger than that of ESC, 46.67 × 106 km2 and 35.65 × 106 km2, respectively. For both ESC and EBR, climate change expanded the northern boundary of potential distributions northward approximately 600 km by the middle of 21st century, and 1000 km by the end of 21st century under RCP 8.5. However, the suitable range decreased to the south in the Southern Hemisphere because of heat stress. The modelled potential distributions of ESC and EBR in the United States demonstrated that the climate was suitable for both weevils. Therefore, considering only climate suitability, both ESC and EBR can be considered as potential biological control agents against A. altissima with some confidence that climatic conditions are likely suitable.