Winged Forms Research Articles

Application of artificial neural network for description of the Earth remote sensing data to identify natural habitats used by European elk, Alces alces (Linnaeus, 1758), in autumn-winter period 2023

The paper presents the results of using neural networks of pixel-by-pixel image classification to decipher multichannel space images obtained by the Landsat 8 satellite. Natural habitats were identified based on differences in phytocenotic characteristics of land areas. The level of use of areas by elk was determined by the occurrence of elk presence indicators, which were the density of winter excrement piles (in spring) and the abundance of winged forms of the monoxenous ectoparasite of elk, Lipoptena cervi (Linnaeus, 1758), as measured by the number of individuals attacking the census taker (in the summer-autumn period). The material that forms the basis for deciphering was obtained by the route census method in different areas of the Leningrad Province. High values of the measured parameters were recorded in reforestation areas, in wet pine and birch forests, in aspen forests, on the edges of raised bogs and in overgrown fields – typical elk winter feeding habitats. Based on the data on the maximum values of the measured parameters, a positive correlation was established for the first time between the abundance of winged forms of L. cervi and the physiological activity of the host (the density of the piles of “winter” excrement). The paper also provides a valid reference to the material of schematic maps developed for a part of the territory of the Leningrad Province and Saint Petersburg. The scheme of the use of areas by elk is compiled on the basis of the relative index calculated from the measured parameters of the survey. Field observation areas and territories close to them were most reliably identified (90–95% accuracy). For areas not covered by field observations, the paper provides comments on the main inaccuracies of the schemes and the reasons for the identified discrepancies, based on an analysis of literary sources devoted to similar research topics. The results of the study indicate that the frequency of attacks of winged forms of L. cervi can be used as an additional criterion for assessing the stationary preferences of elk in the winter period using information on the period of active flight, and the decoding method mentioned in the paper can be used in limited areas of specific territories, including reserves, areas of hunting farms and district forestries.

New morphological and biological contributions to adults and immature forms of Pissonotusparaguayensis (Fulgoromorpha, Delphacidae) in wetlands of Argentina.

In the search for insects as biological control agents for the water primrose, the delphacid Pissonotusparaguayensis (Delphacidae) was found on Ludwigiagrandiflorasubsp.hexapetala (Onagraceae) in a wetland of Central East Argentina. The morphology of the unknown females (brachypterous and macropterous) and immature stages are described and illustrated. Adults and nymphs were collected in wetlands of Del Plata River Basin, from Buenos Aires to the northeastern part of Argentina. A rearing methodology was developed to perform biological studies. Both winged forms and structural features of the female genitalia are described for the first time at the genus level. Eggs and immature stages are described and keyed; fifth nymphal instars may be easily recognised by the yellowish colouration, blackish on dorsal of head, thorax and abdomen with conspicuous yellowish pits, ventrally only darkened on base of frons extended to lower level of eyes and dorsal surface of antennomeres I and II, and legs with distinctive black marks at femoro-tibial joint and apex. The geographical distribution is updated, expanding its range into Argentina, making Buenos Aires the southernmost limit of the genus in America. Biological information of the species is also reported here: life cycle, fecundity, oviposition behaviour, and host plant. Field observations showed that P.paraguayensis breeds, feeds, and causes damage to L.g.subsp.hexapetala. This delphacid presents a certain degree of specificity to the Ludwigia species in the Jussiaea section in host specificity tests. More studies are required to test this species as a potential biological control agent.

АКТИВНОСТЬ ТЛЕЙ-ПЕРЕНОСЧИКОВ ВИРУСОВ КАРТОФЕЛЯ В АРХАНГЕЛЬСКОЙ ОБЛАСТИ

The research was carried out to study the activity of aphids that carry viruses on potato plantings in the southern part of Arkhangelsk region, to assess the degree of their prevalence and the need to apply plant protection measures. The work was carried out in 2018-2022. The catching of winged forms of aphids in potato plantings was carried out using yellow water traps. In total, over a five-year period, 834 aphids were caught visiting potato plantings, which belonged to 30 different species. The most effective carriers of potato viruses are 7 of them - Acyrthosiphum pisum Harr., Aphis fabae Scop., Aphis nasturtii Kalt., Aulacorthum solani Kalt., Hyperomyzus lactucae L., Macrosiphum euphorbiae Thomas and Rhopalosiphum padi L. These species were present on plantings annually (with the exception of M. euphorbiae Thomas), and their numbers varied from 82 (in 2020) to 181 (in 2021) individuals. At the same time, the share of aphids that carry viruses in their total number ranged from 56% (in 2022) to 82% (in 2018). Over the entire period of research, not a single individual of the aphid species Myzus persicae Sulz, the most harmful to potato plantings, was identified. The prevalence of virus-carrying aphids was insignificant; there were from 21 to 46 winged insects per 1 water trap during the growing season in different years. Aphids capable of transmitting potato viruses were present on the plantings throughout the entire growing season, which indicates the need for preventive and exterminatory measures to protect plants, based on systematic annual monitoring, which makes it possible to monitor changes in the species composition, numbers and flight dynamics of aphids.

First record of Melanaphis donacis (Passerini, 1861) (Hemiptera: Aphididae) in México

The aphid Melanaphis donacis (Passerini, 1861) (Hemiptera: Aphididae) is recorded in Mexico in seven locations in the Valley of Mexico Basin on the Poaceae Arundo donax, one of the most common host plants. Both the aphid and the host plant are species considered exotic to Mexico; especially A. donax is referred to as one of the hundred most important invasive alien species in the world and is also officially cited in Mexico. Observations and collections of both the aphid colonies and the host plant began in October 2022 to February 2023. The work includes the taxonomic determination of both the aphid and the host plant. Also reviewed of websites (www.naturalista.mx) where in two sites it was referred to in a preliminary way, without taxonomic certainty by a specialist. In addition to the worldwide distribution of the aphid species and its host plants. Parthenogenetic wingless and winged forms are presented and described in vivo, as well as in mounts of microscope slides. In all the cases observed in the field, a symbiotic association with ants of the species Linepithema humile Mayr, 1868 (Hymenoptera: Formicidae) is documented. Some natural enemies were obtained, such as Harmonia axididis (Palas, 1773) (Coleoptera: Coccinellidae); Scymninae, Chamaemyiidae and Syrphidae larvae, yet to be determined. It is suggested to increase the search both in other localities and in hosts potentially present in Mexico.

Step-by-step Dissection Protocol of Apicotermitinae Worker (Blattaria: Isoptera)

Apicotermitinae are soldierless termites highly abundant in tropical forests. The taxonomy of this subfamily is based on characters of worker cast and winged forms when present. However, the procedures necessary to dissect termite workers to observe their external and internal morphological characteristics are not well detailed in any study. Here, we describe a step-by-step protocol for worker dissection of soldierless termite species. We suggest the use of Polyvinyl Alcohol (PVA) for cleaning and visualization of the gizzard and enteric valve, and glycerin to remove tergites and sternites and describe in detail the dissection of the gizzard and enteric valve, and how visualize the insertion of Malpighian tubules.

Blood meal digestion and changes in lipid reserves are associated with the post-ecdysis development of the flight muscle and ovary in young adults of Rhodnius prolixus

Rhodnius prolixus is a hemimetabolous, hematophagous insect, and both nymphs and adults feed exclusively on blood. The blood feeding triggers the molting process and, after five nymphal instar stages, the insect reaches the winged adult form. After the final ecdysis, the young adult still has a lot of blood in the midgut and, thus, we have investigated the changes in protein and lipid contents that are observed in the insect organs as digestion continues after molting. Total midgut protein content decreased during the days after the ecdysis, and digestion was finished fifteen days later. Simultaneously, proteins and triacylglycerols present in the fat body were mobilized, and their contents decreased, whereas they increased in both the ovary and the flight muscle. In order to evaluate the activity of de novo lipogenesis of each organ, the fat body, ovary and flight muscle were incubated in the presence of radiolabeled acetate, and the fat body showed the highest efficiency rate (around 47%) to convert the taken up acetate into lipids. The levels of de novo lipid synthesis in the flight muscle and ovary were very low. When 3H-palmitate was injected into the young females, its incorporation by the flight muscle was higher than by the ovary or the fat body. In the flight muscle, the 3H-palmitate was similarly distributed amongst triacylglycerols, phospholipids, diacylglycerols and free fatty acids, while in the ovary and fat body it was mostly found in triacylglycerols and phospholipids. The flight muscle was not fully developed after the molt, and at day two no lipid droplets were observed. At day five, very small lipid droplets were present, and they increased in size up to day fifteen. The diameter of the muscle fibers also increased from day two to fifteen, as well as the internuclear distance, indicating that muscle hypertrophy occurred along these days. The lipid droplets from the fat body showed a different pattern, and their diameter decreased after day two, but started to increase again at day ten. The data presented herein describes the development of the flight muscle after the final ecdysis, and modifications that occur regarding lipid stores. We show that, after molting, substrates that are present in the midgut and fat body are mobilized and directed to the ovary and flight muscle, for the adults of R. prolixus to be ready to feed and reproduce.

Identification and reproductive isolation of Euborellia species (Insecta, Dermaptera, Anisolabididae) from East and Southeast Asia.

Euborellia (Anisolabididae: Anisolabidinae) is one of the most speciose genera of earwigs (Dermaptera), and its species-level classification is difficult. To settle the classification of brachypterous species with abbreviated tegmina recorded from East and Southeast Asia, we examined the morphology and reproductive isolation of three tentative Euborellia species, and analyzed the DNA barcoding region of the mitochondrial cytochrome oxidase subunit I (COI) gene. The observed complete reproductive isolation among the three Euborellia taxa and considerable differentiation in the COI sequences clearly show that each should be treated as a separate species. Based on morphology, distribution and the DNA sequence, we identify Euborellia sp. 1 of Malaysia as E.annulata (Fabricius), a circumtropical cosmopolitan with no records of a fully winged form. Samples from Ioto Island (= Iwo-jima Island: Ogasawara Islands, southern Japan) were also identified as this species. Euborellia sp. 3, from the main islands of Japan, was generally larger and lacked a Y-shaped pigmented area on the penis lobe, which is characteristic of Euborellia sp. 1. We propose reinstating E.pallipes (Shiraki) as the oldest name for this taxon. Euborellia sp. 2, even the brachypterous form, can be distinguished from these two species by its paler coloration (particularly the femora), ecarinate post-abdomen, and the shape of the male genitalia (parameres). We tentatively identify this species as E.philippinensis Srivastava based on the morphology of the brachypterous form, although the macropterous form cannot be distinguished from E.femoralis (Dohrn).

Развитие свекловичной тли (Aphis fabae Scop.) в зависимости от различных фотопериодических условий

Among the sucking pests of sugar beet crops in Azerbaijan, black bean aphid (Aphis fabae Sсop.), which occurs on beet seedlings from the moment of development of true leaves, causes significant damage. Based on this, the task of our study was to study the main life processes of beet aphids depending on photoperiodic conditions. The work was carried out in the Laboratory of Ecology and Physiology of Insects and the Center for Applied Zoology of Azerbaijan National Academy of Science in 2013–2019. The experiments were carried out in special photo thermostats with automatic control of temperature and light. The results obtained show that the light factor is of secondary importance for the duration of the larval, reproductive periods and for the entire development cycle compared to temperature. It should be noted that winged forms (about 50%) appear in aphid colonies during a 12-hour photoperiod at a temperature of 17 °C. Under the conditions of Azerbaijan, such photoperiod is observed at the end of March and at the beginning of October, when aphids migrate from primary to intermediate plants and vice versa in autumn (early October) from intermediate to primary. The length of the day established in the experiments, which causes the appearance of winged forms, is consistent with the phenology of this species.

Description of a new species of Hamamelistes forming galls on Fothergilla spp. (Hamamelidaceae) and the generic limits of Hormaphidini (Sternorrhyncha: Aphididae: Hormaphidinae).

Hamamelistes and Hormaphis aphids of the tribe Hormaphidini are distributed disjunctly in eastern North America and Eurasia. Host-alternating species have life cycles encompassing generations in a gall on witch-hazel (Hamamelis spp.) and generations on leaves of birch (Betula spp.). In Hamamelistes, generations on witch-hazel induce globular pouch galls on flower or leaf buds. Herbarium specimens of a related Hamamelidaceae genus, Fothergilla, contain large galls in place of the seed head. We obtained a fresh sample of these elongate pouch galls collected from F. milleri in Alabama, USA. The galls were formed in place of fruiting structures and contained numerous aphids. Examination of morphology and the cytochrome oxidase subunit I barcode DNA sequence confirmed that the aphids are an undescribed species of Hamamelistes. Here, we describe the new species, Hamamelistes blackmani Dederich von Dohlen sp. n., from the morphology of foundresses, immatures, and winged forms in the gall. The life cycle is presumed monoecious. In addition, we review the evidence for including other genera in Hormaphidini and recommend that this tribe be restricted to Hamamelistes and Hormaphis.

Homeopathic solutions induce production of winged forms in aphid

The aphids control (Brevicoryne brassicae L.) in kale (Brassica oleracea L. var. acephala) is one of the main challenges for its production. This obstacle becomes greater in agroecological production systems. Thus, the objective of this study was to verify the formation of winged individuals in colonies of B. brassicae aphids, when exposed to kale treated with homeopathic solutions. The treatments were resistant 5CH, susceptible attacked 5CH, aphid nosode 30CH, and the controls that are water (without dynamization) and distilled water + 70% ethanol 5CH, being applied every day for 15 days. Kale plants were inoculated with aphids and irrigated using homeopathic solutions. After 15 days of inoculation, the plants were removed from the bag and the number of winged forms and nymphs of B. brassicae was counted. Homeopathic preparation Resistant 5CH provided a smaller number of winged individuals and a larger number of nymphs per colony. The plants treated with the susceptible attacked 5CH homeopathy showed a higher number of winged aphids, but a reduced number of nymphs. Aphid nosode 30CH treatment was promising to Brevicoryne brassicae control in kale plants, as it induced polymorphism, presenting a greater number of winged aphids and a reduced number of nymphs per colony.

Cucumber mosaic virus epidemiology in pepper: Aphid dispersal, transmission efficiency and vector pressure

AbstractCucumber mosaic virus (CMV) causes significant damage and yield losses in peppers. The objective of this study is to determine the efficiency of prevalent aphid species occurring in pepper fields to transmit this virus within pepper plants and to identify their vector pressure in order to target the critical species implicated in CMV epidemics spread. Alatae and apterae were monitored in an experimental pepper field in northern Tunisia for 3 years. Sixty‐eight species were captured in winged form in yellow water traps. The most abundant species were Myzus persicae, Aphis gossypii, Aphis fabae, Aphis spiraecola, Acyrthosiphon pisum, Metopolophium dirhodum, Rhopalosiphum maidis, Aphis craccivora, Aphis nerii, Hyalopterus pruni, Sitobion avenae and Rhopalosiphum padi constituting 90% of aphid populations in the field. Their temporal dynamic showed a high period of flight activity from April to June and a second peak in September was registered. Two of these species, M. persicae and A. gossypii were also found in their wingless form on pepper leaves with a prevalence of 99.5% and 0.5%, respectively. The 12 most abundant aphid species were tested for their transmission efficiency of CMV (CMV‐pepp2 isolate) with A. gossypii as a reference vector. All aphids tested, including colonizing and non‐colonizing species on pepper, were verified to be vectors of this isolate. However, significant differences in the transmission efficiency were found between the aphid species (p < .001, SE = 7.29). M. persicae (60%) scored the highest transmission efficiency rate. Additionally, A. fabae solanella (50%) had higher transmission efficiency than the reference vector, A. gossypii (40%). H. pruni (16.67%) was documented as a new CMV vector to pepper. The single‐aphid transmission probabilities ranged from 0.7% to 16.7%. The calculated mean Vector Pressure Index (VPI) for these 12 species showed a stronger relationship with the specific aphid population variance (R = 0.89, p < .01) than the variation of the specific single‐aphid transmission probabilities (R = 0.62, p < .05). Indeed, for alate non‐colonizer vectors, A. spiraecola has recorded the highest mean VPI (27.5), despite its moderate transmission efficiency (23.33%). Nevertheless, for colonizer vectors in both winged and wingless forms, M. persicae had the highest mean VPI (49.26) of all vector species and was mostly present in its apterous form. The 12 vector species contributed to a total mean VPI of 133.48 during the surveyed periods. This research determined key features of CMV epidemiology in pepper crops that might be helpful for CMV disease management at an early stage.

Aphis spiraecola and Aphis (Toxoptera) citricidus differently manipulate plant metabolism to gain fitness in terms of population abundance or dispersal

AbstractThe response of plant cultivars to infestation by single aphid species has been widely reported, whereas the response of plants to multiple aphid species, and the mechanisms by which various aphids benefit from the induced changes, has been largely ignored. Here we analyzed the symptoms and physiological responses of sweet orange, Citrus sinensis (L.) Osbeck (Rutaceae), as affected by Aphis spiraecola Patch and Aphis (Toxoptera) citricidus (Kirkaldy) (Hemiptera: Aphididae). We further compared the feeding behavior, population abundance, and proportion of winged morph of the two aphid species when separately feeding on sweet orange. Results showed that feeding by A. spiraecola, but not A. citricidus, caused leaf curling, reduced shoot length, shoot fresh weight, and chlorophyll concentration. In addition, A. spiraecola feeding increased the concentration of essential amino acids in leaves when compared with A. citricidus and uninfested control plants. Electrical penetration graph‐studies showed that A. citricidus gained faster access and acceptance of phloem, and spent more time ingesting phloem sap, than A. spiraecola. Furthermore, after 2 weeks of infestation, A. spiraecola produced more winged morphs, whereas A. citricidus achieved higher population abundance. Thus, our results indicate that the two citrus aphids utilize divergent strategies to manipulate host metabolism, and gain fitness benefits in population abundance or winged form production. The results could improve our understanding of varied adaptive strategies of co‐existing insects and extend our knowledge of aphid‐plant interactions.

Riqueza e composição de Térmitas (Blattodea, Isoptera) em manguezais do litoral amazônico

Among the varieties of insects present in mangroves, termites can easily colonize mangrove forests by their winged forms, and thus, build arboreal nests. In view of the presence of this order in mangroves, this work presents the results of a sampling of Termites (Blattaria, Isoptera) in mangrove forests on the Amazon coast, as well as highlighting ecological aspects of these insects. Two collections were carried out during an annual cycle (dry and rainy) at six sampling sites located in the mangroves of Soure on Marajó Island, Pará. In each sampling site, a 100 mx 3 m transection was delimited, subdivided into 10 plots of land. 5 mx 3 m, with an interval of 5 m between each plot, with a sampling effort of 1h / person in each plot in search of termites in the different microhabitats present in the mangrove. A total of seven species distributed in three genera and three families were found over an annual cycle. The most abundant species were Nasutitermes corniger (Motschulsky, 1855) (38.70%), Nasutitermes nigriceps (Haldeman, 1853) (25.00%) and Nasutitermes surinamensis (Holmgren, 1910) (20.16%). The xylophagous termites were dominant and the dry season the number of species and specimens was higher.

Comparing the Individual and Combined Effects of Ant Attendance and Wing Formation on Aphid Body Size and Reproduction

AbstractSpecies employ multiple strategies to deal with stressful environments, but these strategies often incur costs. Aphids frequently utilize multiple predator avoidance strategies, including attracting mutualist ants for protection and dispersing by producing winged forms. While both strategies can be physiologically costly, the magnitudes of these costs have not been previously compared. In this study, we experimentally manipulated ant attendance in the field and measured the individual and interactive effects of ant attendance and wing formation on body size and reproduction of the ant-tended aphid Cinara schwarzii (Wilson) (Hemiptera: Aphididae). Aphid adult body size was smaller in the presence of ants (18%), but controlling for body size, there were no differences in embryo number or size. In contrast, wing formation did not affect adult body size but strongly reduced embryo number (46%) and size (8%). Although ant attendance reduced C. schwarzii wing formation, ant attendance and wing formation acted independently on aphid body size and reproduction. For comparison, we confirmed that the manipulation of ant presence had no effect on body size or reproduction of the untended co-existing congener Cinara solitaria (Gillette and Palmer) (Hemiptera: Aphididae). Complementing our empirical study, a meta-analysis of 78 responses from 24 publications showed that wing formation consistently and significantly reduces aphid body size and reproduction (37%), while the effects of ant attendance showed a mean positive effect (9%) that did not significantly differ from zero. Together, our empirical study and meta-analysis provide strong evidence for costs of wing formation but not ant attendance for aphids.

Применение ловушек Малеза для изучения фауны жуков-фитофагов (coleoptera: chrysomeloidea, curculionoidea) Карадагского природного заповедника (республика Крым)

Analysis of the collection of beetles obtained using three Malaise traps during the field season of 2019 in the Karadag Nature Reserve revealed 46 species of phytophagous beetles from 6 families. Of these, 20 species for the fauna of Karadag were first indicated. Two species – Bruchus tristiculus (Bruchidae) and Alcidodes karelinii (Curculionidae) were first listed for the fauna of Crimea. In addition, according to an extensive series of specimens, the poorly studied winged form Longitarsus succineus (Foudras, 1860) (var. perfectus Weise, 1893) (Chrysomelidae) was first recorded in Crimea. In the sample is dominated by West-Central-Palaearctic species and West Palaearctic subboreal species, 9 species have Mediterranean or Pontic ranges (Luperus armeniacus, Phyllotreta aerea, Bruchus rufipes, B. tristiculus, Bruchidius dispar, Bradybatus seriesetosus, Otiorhynchus balcanicus, Polydrusus astutus, Eusomostrophus elongatus). Altogether, beetles from 27 families were collected by tent traps, while phytophagous beetles quantitatively prevailed over other groups of the order. The use of Malaise traps in different biotopes as an additional method for the stationary study of the local fauna of phytophagous beetles is recommended.

MODELING THE GROWTH RATES OF ALIEN INSECTS SPECIFIED DIFFERENTIATED BY STAGES OF ONTOGENESIS

Our studies are devoted to various aspects of invasive processes in biosystems. When invading aggressive insects, the resistance of the biotic environment is significant, but the final time may be completely absent. Under conditions of high specific fecundity, there will be non-stationary regimes of changes in the abundance of individuals in the population. An outbreak with a phase of explosive growth is realized, so we modeled one particular variant of an outbreak of populations earlier. Outbreaks are associated with a number of changes in physiological regulation that are observed in ecodynamics under extreme conditions of the species and environment. A classic example of changes is the appearance of migratory winged forms in the locust and the usually flightless leaf beetle introduced in the Stavropol Territory Zygogramma suturalis during the formation of a population wave front with a huge density of individuals. Traditional mathematical models for describing the rates of average weight gain for individuals of a generation cannot consider situations of rapid invasions, where competition and survival factors at different stages of insect development are very different, since the density of generations varies by orders of magnitude. Effect on growth of local congestion value may not be constant in ontogenesis. The factor of the total number is reflected differently at different stages of life. The purpose of the simulation is to obtain a bistable and flexible dynamic system. The article proposes a model for a differentiated description of weight gain at three stages of development of insects with an incomplete cycle of transformations by three differential equations conjugated by initial conditions. As a result, a continuously discrete dynamic system with a hybrid representation of time on the life cycle interval is implemented. We will use the model when supplementing the hybrid computing structure for calculating the rate of decline of individuals of generations. Mortality changes dramatically with the launch and attenuation of an invasive outbreak. Here, the deviation of growth rates from optimal values plays a role. The idea of the work is that all processes: changes in numbers or growth for insects should be simulated by the stages of development of their ontogenesis.

Transcriptome profiling of maternal stress-induced wing dimorphism in pea aphids.

Wing dimorphism, that is, wingless and winged forms, can be induced by maternal stress signals and is an adaptive response of aphids to environmental changes. Here, we investigated the ecological and molecular effects of three kinds of stress, namely crowding, predation, and aphid alarm pheromone, on wing dimorphism. These three stressors induced high proportion of up to 60% of winged morphs in offspring. Transcriptome analysis of stress‐treated female aphids revealed different changes in maternal gene expression induced by the three stressors. Crowding elicited widespread changes in the expression of genes involved in nutrient accumulation and energy mobilization. Distinct from crowding, predation caused dramatic expression changes in cuticle protein (CP) genes. Twenty‐three CP genes that belong to CP RR2 subfamily and are highly expressed in legs and embryos were greatly repressed by the presence of ladybird. By contrast, application of alarm pheromone, E‐β‐farnesene, caused slight changes in gene expression. The three factors shared a responsive gene, cuticle protein 43. This study reveals the adaptive response of aphids to environmental stresses and provides a rich resource on genome‐wide expression genes for exploring molecular mechanisms of ecological adaptation in aphids.OPEN RESEARCH BADGES This article has earned an Open Data Badge for making publicly available the digitally‐shareable data necessary to reproduce the reported results. The data is available at https://doi.org/10.5061/dryad.55b2b15.

A glance at the deep past history of insects

A glance at the deep past history of insects

A reaction-diffusion-advection model for Aedes aegypti mosquitoes in a time-periodic environment

In this paper we consider a reaction–diffusion–advection model in a heterogeneous time-periodic environment to understand the dynamical behaviors of the Aedes aegypti mosquitoes, which are divided into two sub-populations: the winged form and an aquatic population. The left and right free boundaries are utilized to represent the expanding fronts of the habitat. The spatial–temporal threshold R0F(t) depending on spatial heterogeneity, temporal-periodicity, spatial diffusion and advection is introduced and investigated. Sufficient conditions for the vanishing or spreading of the mosquitoes are given and the long-time dynamical behavior of the solution when spreading occurs is discussed. Our analytical results show that small rate of oviposition and big mortality rates tend to enhance the eradication of the Aedes aegypti mosquitoes.

Survivability of Imaginal Forms of Deer Louse Flies (Diptera, Hippoboscidae)

The purpose of the research is to study the lifespan of Lipoptena cervi imaginal forms under exposure of different temperature conditions and humidity. Materials and methods. L. cervi caught in natural habitats and taken off from marals’ skin served as the material for the research. Overall, 38 samplings have been conducted, 18 thousand L. cervi have been sampled. Caught imagoes were put into mattresses after suffocation with ether-chloroform mixture; the most viable insects were used in experiments. Research for L. cervi lifespan except host of volatiles (not fed) and taken off from marals were conducted under exposure of different temperature conditions and humidity as well as in different types of cages, in wool on skins that were taken off. L. cervi were kept in small quantities in free cages made of capron mesh. Results and discussion. The winged forms under mid-mountain zone conditions of the Republic of Altai can be seen from June up to October; wingless forms (on the feeders’ body) can be seen from June of the current year up to June of the following year and including. Chrysalides are present in nature throughout the year, as L. cervi can’t hatch out from chrysalides of the previous year generation fast enough in June and July before the chrysalides of the new generation begin to appear. The weight of the hatched out L. cervi is 7.9-11.5 mg, they die if the weight is decreased up to 3.0-3.9 mg. It would appear that, the energy and water reserve is 4.9-7.6 mg per one insect. Young not fed L. cervi live rather longer than sexually mature insects. The L. cervi lifespan reliably increases without food as the humidity increases. The longest lifespan is when the humidity is about 60-80% and temperature is about 14-16°С. In laboratory conditions, at the air temperature of about 20-25°C, the humidity of about 60-80%, and moderate airing the chrysalis development lasts for 90 days on the average.