Genetic evidence for the origin of Aedes aegypti,the yellow fever mosquito,in the southwestern Indian Ocean

Aedes aegypti is among the best‐studied mosquitoes due to its critical role as a vector of human pathogens and ease of laboratory rearing. Until now, this species was thought to have originated in continental Africa, and subsequently colonized much of the world following the establishment of global trade routes. However, populations of this mosquito on the islands in the southwestern Indian Ocean (SWIO), where the species occurs with its nearest relatives referred to as the Aegypti Group, have received little study. We re‐evaluated the evolutionary history of Ae. aegypti and these relatives, using three data sets: nucleotide sequence data, 18,489 SNPs and 12 microsatellites. We found that: (a) the Aegypti Group diverged 16 MYA (95% HPD: 7–28 MYA) from its nearest African/Asian ancestor; (b) SWIO populations of Ae. aegypti are basal to continental African populations; (c) after diverging 7 MYA (95% HPD: 4–15 MYA) from its nearest formally described relative (Ae. mascarensis), Ae. aegypti moved to continental Africa less than 85,000 years ago, where it recently (<1,000 years ago) split into two recognized subspecies Ae. aegypti formosus and a human commensal, Ae. aegypti aegypti; (d) the Madagascar samples form a clade more distant from all other Ae. aegypti than the named species Ae. mascarensis, implying that Madagascar may harbour a new cryptic species; and (e) there is evidence of introgression between Ae. mascarensis and Ae. aegypti on Réunion, and between the two subspecies elsewhere in the SWIO, a likely consequence of recent introductions of domestic Ae. aegypti aegypti from Asia.     

鳞翅目昆虫抗病毒免疫反应的研究进展

鳞翅目昆虫种类繁多,对农业生产和人类生活产生重大影响,宿主昆虫与病毒相互关系的研究对于利用病毒杀虫剂进行害虫治理和益虫病毒性疾病的预防具有重要意义.因此,鳞翅目昆虫与病毒的互作研究显得尤为重要,宿主昆虫的免疫系统在抗病毒感染过程中发挥着关键作用,对病毒产生不同程度的免疫反应.本文综述了昆虫围食膜和中肠对病毒入侵的防御作用,病毒进入体腔后昆虫所产生的细胞免疫和体液免疫反应,以及RNAi、细胞的自噬与凋亡、Toll、Imd、JAK-STAT和STING信号通路等相关的抗病毒免疫途径,并对昆虫抗病毒免疫研究的制约因素和未来鳞翅目昆虫抗病毒免疫的研究重点进行了讨论,以期为害虫的生物防治和益虫疾病的防控提供理论依据.     

双斑蟋营养成分分析及评价

由于具有较好的营养价值以及较高的食物转化效率,食用昆虫特别是蟋蟀受到普遍关注。在双斑蟋（Gryllus bimaculatus,GB）营养成分测定的基础上,对比家蟋（Acheta domesticus,AD）和黑蟋（Gryllus testaceus,GT）的营养及含量,分析评价了双斑蟋的使用价值。结果显示：双斑蟋水分含量71.0%、粗蛋白含量58.60%（干重）、粗脂肪含量28.90%（干重）、粗纤维含量7.23%（干重）、灰分4.93%（干重）;蛋白含量与黑蟋相当而高于家蟋,粗脂肪和灰分含量要高于家蟋和黑蟋;双斑蟋含有17种氨基酸,总氨基酸含量51.03%（干重）,必需氨基酸含量24.76%（干重）、占总氨基酸的48.3%,氨基酸含量低于其他两种蟋蟀;双斑蟋中常量元素含量最高的为钾（6 416 mg/kg,干重）、含量最低的是钙（92 mg/kg,干重）,微量元素中锌含量较高（241 mg/kg,干重）;双斑蟋油脂中不饱和脂肪酸的相对含量为65.33%,以亚油酸（37.05%）和油酸（25.86%）为主、饱和脂肪酸以棕榈酸（25.44%）和硬脂酸（8.74%）为主。双斑蟋的脂肪酸组成、含量与家蟋相近,而与黑蟋的脂肪酸组成差别较大,三种蟋蟀中含量最高的饱和脂肪酸为棕榈酸,而含量最高的不饱和酸为亚油酸。结果表明,双斑蟋的必需氨基酸组成符合FAO/WHO推荐的氨基酸构成比例的蛋白条件,具有较高的营养价值和食用价值。     

Growth performance and feed conversion of Ruspolia differens on plant-based by-product diets

The use of food industry by-products in insect feeds has gained increasing attention recently. However, the understanding of how well the economically valuable edible insect Ruspolia differens (Serville) (Orthoptera: Tettigoniidae) can grow and develop with plant-based by-product feeds is currently lacking. It is important to determine the nutritional requirements, especially protein demand, of this species before developing artificial feeds for mass-rearing. We reared R. differens with four control diets and 12 plant-based by-product diets in which the major protein source came from food industry by-products, including potato-protein, barley mash, barley feed, turnip rape, a mix of broad bean and pea, and a mix of potato, carrot, and apple. We asked whether the performance (development time, survival, and weight), feed conversion, and fatty acid composition and content differed among diet treatments. Furthermore, the 12 experimental by-product diets were designed to reach six protein levels. We found that R. differens can be reared with various by-product diets, but development time, survival, and weight differed among diets. Barley feed, barley mash, and potato protein diets seem to be good options for rearing, and potato glycoalkaloids do not affect the performance of R. differens. Individuals fed on the various by-product diets also differed in their fatty acid composition and content. Increasing protein levels in diet up to 17% enhanced growth, development time, and survival, but no further enhancements were seen when fed diets with protein levels higher than this. The high protein levels decreased feed conversion rate. Our results can be valuable for designing feeds for insect mass-rearing technology. The use of food industry by-products in the diets for R. differens could increase the re-use of local resources and enhance circular economy.     

Revision of fossil Metretopodidae (Insecta: Ephemeroptera) in Baltic amber – Part 2: Description of a new species of Metretopus Eaton, 1901

In the second part of the revision of fossil Metretopodidae, a new species of the genus Metretopus Eaton, 1901 is described and illustrated based on a male imago. Metretopus dividussp. nov. is the second fossil species of the genus. Distinguishing characters for its separation from other fossil and recent representatives of Metretopus are discussed. http://www.zoobank.org/urn:lsid:zoobank.org:act:BCC5CB69-8014-4DA1-A0DA-DCF714969081     

Environmental Cues,Endocrine Factors,and Reproductive Diapause in Male Insects

Environmental cues, mostly photoperiod and temperature, mediated by effects on the neuroendocrine system, control reproductive diapause in female insects. Arrest of oocyte development characterizes female reproductive diapause, which has two major adaptive functions: It improves chances of survival during unfavorable season(s), and/or it confines oviposition to that period of the year that is optimal for survival of the eggs and progeny. Although reproductive diapause is less well studied in male insects, there may be no sex-dependent differences in regard to the first of these functions. The second one, however, is not valid for the male; instead, selection pressure directs the male's reproductive strategy toward maximum chances of fertilization of the female's eggs with minimum waste of energy. Therefore, in species with female reproductive diapause, the males may or may not exhibit diapause, but if they do, their diapause must be adapted to that existing in conspecific females. Male reproductive diapause is defined as a reversible state of inability of the male to inseminate receptive females. In relation to reproductive diapause, there are several patterns of coadaptations between male reproductive strategy and timing of female receptivity, (a) In some insects, the females are receptive in the early part of their diapause; mating occurs during this period and there is no diapause in the male. The male dies shortly after copulation and the female stores the sperms to fertilize the eggs that develop after termination of the female's diapause, (b) In some species, as in the grasshopper Anacridium aegyptium, females are receptive during diapause; though oocyte development is arrested, copulation occurs and the stored sperms fertilize the eggs when the female's diapause ends. Males were claimed to have no diapause, but recent studies have revealed the presence of a reproductive diapause in a proportion of the males. This and other cases show that female receptivity during reproductive diapause may or may not be accompanied by male reproductive diapause. If there is a reproductive diapause in the male, it is controlled by the same endocrine mechanism, the corpora allata (CA), as in the females, (c) In many species females are refractory during their diapause. In these cases, males exhibit reproductive diapause, which may be light, as in the beetle Oulema melanopus, or well established, as in certain grasshoppers, butterflies, and beetles. In the latter cases, male diapause is controlled by similar environmental cues (photoperiod, temperature) and by the same intrinsic mechanism (neuroendocrine system, especially CA) as female diapause. Nevertheless, male diapause is less intense; the environmental cues leading to its termination are less complex and/or less extreme, so male diapause terminates before that of the females. Presumably, male diapause is under two antagonistic selection pressures: A male should not waste energy by courting dia-pausing refractory females, but he should be ready to copulate as soon as the females become receptive, otherwise he may lose in the competition between males for females. Some further strategies, which do not seem to fit the above patterns, are also outlined.     

The fine structure of the sperm bundles of the coccid,Aspidiotus perniciosus Cumst., and sperm movement

The mature sperm of A. perniciosus are organized into bundles, about 350 μm long by 9–10 μm wide. Each bundle contains 32 sperm enclosed by a common sheath. The sperm contains an elongated ‘central core’, representing nuclear material, surrounded by a spiral microtubular sheath and cytoplasm. The electron-dense nuclear material is localized in the more pointed half of the sperm. The spiral microtubular sheath is composed of 30— 100 microtubules (depending on the cross-sectional level), situated parallel to the longitudinal axis of the sperm. On the basis of this ultrastructural organization, the motility of the sperm and sperm bundle as a whole is discussed. The sperm of A. perniciosus provide strong evidence that the microtubules arranged asymmetrically represent the elements directly involved in sperm motility.     

New records of Cynipidae (Hymenoptera) from Italy

New records of Cynipid gall wasps and inquilines for the Italian peninsula and Sicily and their new host plants for the Palaearctic Region are listed and commented on. Among them we find: Cerroneuroterus cerrifloralis (Müllner 1901) as new for Italy and new for the Palaearctic region as host on Quercus suber; Andricus multiplicatus Giraud 1859 on Q. suber, as new host for the Palaearctic region; Aylax papaveris (Perris 1839), reported in Italy over a century ago, but later overlooked; Cerroneuroterus minutulus (Giraud 1859), also reported more than a century ago from Sicily, but later overlooked. Among the inquilines are here listed: Synergus variabilis Mayr 1872, emerged from Janetia cerris (Kollar 1850) galls (Diptera Cecidomyiidae), and found for the first time in the Palaearctic Region as host on Q. suber; Saphonecrus haimi (Mayr 1872) and Saphonecrus barbotini Pujade-Villar & Nieves-Aldrey 1986, are new records for Italy.     

Dufour’s gland secretion,sterility and foraging behavior: Correlated behavior traits in bumblebee workers

Bombus terrestris colonies go through two major phases: the “pre-competition phase” in which the queen is the sole reproducer and aggression is rare, and the “competition phase” in which workers aggressively compete over reproduction. Conflicts over reproduction are partially regulated by a group of octyl esters that are produced in Dufour’s gland of reproductively subordinate workers and protect them from being aggressed. However, workers possess octyl esters even before overt aggression occurs, raising the question of why produce the ester-signal before it is functionally necessary?In most insect societies, foragers show reduced aggression and low dominance rank. We hypothesize that ester production in B. terrestris is not only correlated with sterility but also with foraging, signaling cooperative behavior by subordinate workers. Such a signal helps to maintain social organization, reduce the cost of fights between reproductives and helpers, and increase colony productivity, enabling subordinates to gain greater inclusive fitness. We demonstrate that foragers produce larger amounts of esters compared to non-foragers, and that their amounts positively correlate with foraging efforts. We further suggest that task performance, potential fecundity, and aggression are interlinked, and that worker–worker interactions are involved in regulating foraging behavior.B. terrestris, being an intermediate phase between primitive and derived eusocial insects, provides an excellent model for understanding the evolution of early phases of eusociality. Our results, combined with those in primitively eusocial wasps, suggest that at early stages of social evolution, reproduction was regulated by a “primordial division of labor”, that comprised foragers and reproducers, which further evolved to a more complex division of labor, a hallmark of eusociality.