Insect Migration Research Articles

Influence of seasonal migration on evolution of insecticide resistance in Plutella xylostella.

The diamondback moth, Plutella xylostella (L.), is one of the most destructive migratory pest species of cruciferous vegetables worldwide and has developed resistance to most of the insecticides used for its control. The migration regularity, migratory behavior, and relationship between flight and reproduction of P. xylostella have been widely reported. However, the effect of migration on insecticide resistance in this pest is still unclear. In this study, the effect of migration on P. xylostella resistance to seven insecticides was investigated using populations across the Bohai Sea that were collected in the early and late seasons during 2017-2019. The bioassay results showed that the early season populations of P. xylostella from south China possessed much higher resistance to insecticides because of intensive insecticide application; alternatively, the late season populations migrated from northeast China, where the insecticides were only used occasionally, showed much lower insecticide resistance. The genome re-sequencing results revealed that, among the eight mutations involved in insecticide resistance, the frequencies of two acetylcholinesterase mutations (A298S and G324A) responsible for organophosphorus insecticide resistance were significantly decreased in the late season populations. The results indicated that P. xylostella migration between tropical and temperate regions significantly delayed the development of insecticide resistance. These findings illustrated the effect of regional migration on the evolution of insecticide resistance in P. xylostella, and provided foundational information for further research on the relationship between migration and insecticide resistance development in other insects.

ENTOMOLOGICAL SENSORS FOR CONSERVATION TECHNOLOGIES OF CROP CULTIVATION IN FIELD CROP ROTATIONS OF THE FOREST-STEPPE OF UKRAINE

In 2010-2022, in the field crop rotations of the Forest-Steppe of Ukraine, using the latest chemicals, the peculiarities of biology, ecology and distribution of soil and other harmful arthropod species were clarified. In particular, the technologies for the production of high-quality grain through the use of tank mixtures of plant protection products and relatively high rates of fertilizers influenced the formation of the structure of the entomocomplex with the prevalence of certain species of grasshoppers, blackflies, scoopers and plateworms. According to the phenophases of cultivated plants, this feature was accompanied by both the state of bioresources and crop production technologies in general with the optimisation of phytosanitary, environmental and economically sound resource-saving methods of phytophage number control. It has been established that in cultural ecosystems with intensive technologies as part of modern biological resources, the number of organisms, both flora and fauna, in particular, harmful insect phytophages, changes significantly in the early stages of formation and development of grain crops. During the years of observation, it was noted that the biodiversity of agrocenoses is quite numerous in terms of species and quantity, mainly against the background of organic-mineral systems and under conditions of relatively low rates of fertiliser application. This makes it possible to model such processes using entomological and zoological objects as sensors, in particular from the standpoint of systematic monitoring and forecasting, as well as sustainable management on a resource-saving basis. At the same time, the long-term dynamics of the factors of entomocomplexes formation was taken into account, with the influence of basic and fractional feeding systems, soil cultivation and measures to protect cereals and other crops being clarified, and the dominant species were identified from the theological point of view. Based on the results of the research, some biocenotic relationships of cultivated plants and their pests under different nutrition systems of wheat, corn, soybeans, chickpeas, sunflower in periods of drought and relatively optimal weather conditions were clarified, with the levels of trophic chains of primary and secondary cenoses determined. The structure of arthropods under the latest systems of liquid fertiliser application was clarified, as well as the impact of tank mixtures of agrochemicals on the migration and survival of phytophagous insects in short rotation crop rotations was assessed. The new parameters of grain crop protection systems with biologically oriented complexes based on entomological and zoological test objects of the factors of crop production intensification are substantiated.

Estimating Insect Body Size From Radar Observations Using Feature Selection and Machine Learning

For insect radar observations, exploiting radar echoes from insects to accurately estimate size parameters such as body mass, length, and width of insects can help to identify insect species. At present, the commonly used method for estimating insect body size parameters in insect radar is to use the monotonic mapping relationship between insect RCS parameters of a single frequency (mainly 9.4 GHz) and body size, and obtain the empirical formula for body size estimation by polynomial fitting. However, the useful information used by the traditional methods is limited (1 to 2 features), and these retrieval methods are simple and with limited estimation accuracy. This paper proposed a feature-selection-based machine learning method for insect body size estimation, which could effectively improve the body size parameter estimation accuracy of insect radars. First of all, based on the published insect scattering dataset (9.4GHz, 366 specimens of 76 species), stepwise regression was used to select the optimal feature combinations for body size estimation, then three machine learning methods, Random Forest Regression (RFR), Support Vector Regression (SVR) and Multilayer Perceptron (MLP), were adopted to achieve estimation of insect body size. Among them, RFR has the best performance (mass 18.83%, length 11.37%, width 16.87%). Subsequently, based on the measured dataset of migratory insects (5532 specimens of 23 species), the influence of the estimation error of insect body size on the identification accuracy of migratory insect species was analyzed. When incorporating the estimation error of the feature-selection-based RFR method, the insect identification rate of 83.68% was reached.

Joint Association and Registration in a Multiradar System for Migratory Insect Track Observation

The migration of insects is an important way of material and energy transfer in nature. The accurate multitargets’ tracks are beneficial for studying insect flight mechanisms. Radar has been widely used in insect observation. Compared with a single radar system, a multiradar system can provide measurements from more dimensions and produce more accurate flight tracks. However, for insect observation, there are lots of targets and outliers in the measurement sets, which may challenge the measurement-to-measurement association between different radars. In addition, sensor bias estimation is needed to achieve good association and fusion results. We propose a joint association and registration method to simultaneously acquire bias estimates and association results for insect observation. The Gaussian-Seidel method is applied to solve the nonlinear least square bias estimate problem without any approximation. The Cramér-Rao bound is derived in the article. The simulation results show that our method can achieve the best association performance for different scenarios among the competing approaches, and bias estimation results are insensitive to the bias values, that can improve the accuracy of the fusion tracks.

Adaptation to the hottest spot on earth: Dietary ecology of an enigmatic desert gecko based on DNA metabarcoding

The Lut Desert, southeastern Iran, regularly has the largest contiguous area of surface temperatures above 65°C compared to anywhere else on Earth. Despite these harsh conditions, some specialized species thrive in this extreme habitat. Misonne's spider gecko, Rhinogecko misonnei de Witte, 1973 (Reptilia, Squamata, Gekkonidae) is an endemic species that is native to the central part of the Lut Desert. This research aimed to explore the dietary gut content and ecology of Misonne's spider gecko populations inhabiting the Lut Desert. A DNA metabarcoding approach was applied to obtain data from the stomach content of six collected specimens. A total of 147,451 amplicon reads representing a total of 94 OTU (=Operational Taxonomic Units) for the CO1-5P barcode region were sequenced. Of 94 OTUs, 50 (53.2%) identically matched ≥97% with BOLD and/or NCBI database and were identified at the genus level. Blasting in both databases revealed the presence of three phyla including Chordata (55.23%), Arthropoda (44.72%), and Annelida (0.05). 99.54% of Chordata DNA belonged to Rhinogecko misonnei mainly coming from stomach tissue of the examined specimens. Within the arthropods, 87.64% of the OTUs matched Insecta and 12.08% Arachnida. Our findings indicate that Rhinogecko misonnei is a generalist gecko that feeds on a variety of food items. About 81% of Rhinogecko food items in the central Lut are migratory insects that come from adjacent areas of the Lut District, although the arachnid food items originate from the central Lut. This study emphasizes the importance of the insect fauna of adjacent areas of the Lut Desert for the stability of the Desert food web.

Hoverflies use a time-compensated sun compass to orientate during autumn migration.

The sun is the most reliable celestial cue for orientation available to daytime migrants. It is widely assumed that diurnal migratory insects use a ‘time-compensated sun compass’ to adjust for the changing position of the sun throughout the day, as demonstrated in some butterfly species. The mechanisms used by other groups of diurnal insect migrants remain to be elucidated. Migratory species of hoverflies (Diptera: Syrphidae) are one of the most abundant and beneficial groups of diurnal migrants, providing multiple ecosystem services and undergoing directed seasonal movements throughout much of the temperate zone. To identify the hoverfly navigational strategy, a flight simulator was used to measure orientation responses of the hoverflies Scaeva pyrastri and Scaeva selenitica to celestial cues during their autumn migration. Hoverflies oriented southwards when they could see the sun and shifted this orientation westward following a 6 h advance of their circadian clocks. Our results demonstrate the use of a time-compensated sun compass as the primary navigational mechanism, consistent with field observations that hoverfly migration occurs predominately under clear and sunny conditions.

Design of Insect Target Tracking Algorithm in Clutter Based on the Multidimensional Feature Fusion Strategy

Entomological radar is an effective means of monitoring insect migration, and can realize long-distance and large-scale rapid monitoring. The stable tracking of individual insect targets is the basic premise underlying the identification of insect species and the study of insect migration mechanisms. However, the complex motion trajectory and large number of false measurements decrease the performance of insect target tracking. In this paper, an insect target tracking algorithm in clutter was designed based on the multidimensional feature fusion strategy (ITT-MFF). Firstly, multiple feature parameters of measurements were fused to calculate the membership of measurements and target, thereby improving the data association accuracy in the presence of clutter. Secondly, a distance-correction factor was introduced to the probabilistic data association (PDA) algorithm to accomplish multi-target data association with a low computational cost. Finally, simulation scenarios with different target numbers and clutter densities were constructed to verify the effectiveness of the proposed method. The tracking result comparisons of the experimental data acquired from a Ku-band entomological radar also indicate that the proposed method can effectively reduce computational cost while maintaining high tracking precision, and is suitable for engineering implementation.

Increasing temperature reduces cuticular melanism and immunity to fungal infection in a migratory insect

1. Few studies have considered how global warming affects disease resistance. Many ectotherms depress the melanisation of exposed surfaces to reflect more sunlight in warmer habitats. Because phenoloxidase (PO) enhances both cuticular melanisation and the innate immune response to invasion, we asked: is decreased melanism in response to higher temperatures associated with less PO activity and greater vulnerability to entomopathogenic fungal attack?2. We measured spontaneous PO activity from wounding and circulating total PO activity before topical application ofBeauveria bassianafungus and 2 days following inoculation.3.Melanoplus sanguinipesgrasshoppers reared in higher temperatures were paler, and had lower spontaneous PO activity and total PO both before and after the fungal attack. They were also more susceptible toBeauveria bassianafungal attack than those reared in cooler temperatures. Hence, thermoregulatory benefits of decreased melanism for growth, reproduction, and survival can be compromised by reduced PO activity and the immune response to fungal infection.4. As the Earth warms, these two functions of PO, thermoregulation and immunity, are likely to remain associated with one another, which may cause thermal melanism to be detrimental to an insect population's resilience to climate change.

Male nutritional status does not impact the reproductive potential of female Cnaphalocrocis medinalis moths under conditions of nutrient shortage.

In addition to sperm, some accessory substances transferred to females during copulation act as nuptial gifts by passing on valuable nutrients in many insect species. The nutritional status of the males can thus have a great effect on the mating behavior, fecundity and even the longevity of females. However, little is known about the effect of male nutritional status on the female reproductive traits in migratory insect species, particularly when females experience nutrient shortage and have to choose between reproduction and migration. Here, Cnaphalocrocis medinalis, a migratory rice pest in Asia, was studied to explore this issue. Our results showed that in male moths fed with honey solution, their gonads had higher energy content than gonads of starved males, resulting in increased energy content of the bursa copulatrix of females after mating with fed males. Such females showed increased mating frequency, fecundity and longevity compared to females mating with starved males, indicating that male moths deliver nuptial gifts to females and improve their reproductive performance. However, when females were starved, only about 45% mated, with just a single copulation, regardless of male nutritional status. Starved females showed lower fecundity, and a longer pre-oviposition period (indicating a greater propensity to migrate), compared to fed females. However, copulation still significantly extended their longevity. These results suggest that starved females invest in migration to escape deteriorating habitats, rather than investing the nuptial gift to increased fecundity. Our results further our understanding of the reproductive adaptability of migratory insects under conditions of food stress.

Integrated Management of Phthorimaea operculella (Zeller) Infesting Solanum tuberosum L. in Storage in MT Elgon Region, Kenya

The production of potato, a second major staple food crop in Kenya is being constrained by an insect pest potato tuber moth (PTM), Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae). The present study investigated two Integrated Pest Management techniques which would reduce (PTM) population in potato storage, four potato cultivars and two botanical quantities were used in storage in Mt Elgon region of Western Kenya. The insecticidal efficacy of Lantana camara L. and Azandiracta indica A. Jusss (Sapindales: Meliaceae) and in storage at Kapsokwony and Chemoremo villages were investigated in the present study years. In each of the studied site the experiment was laid down in randomized block Design (RBD) in a split plot arrangement at room temperature of 27 ± 2. Four cultivars (Tigoni, Sherekea, Mayan gold and Asante) were the first factor and treatments (L. camara and A. indica leaves powder and control) as the second factor, each of which was repeated three. The room was partitioned at the center into two (3m x3m) using a PVC sheet to separate two portions for the two botanical and to prevented insect migration. We set up 4 caring bags per cultivar per botanical. We placed 2 kg PTM-free tubers per each cultivar in one caring bag hence 4 caring bags/split/ cultivar and 16 caring bags / block, therefore the total number of caring bags was (4 x 4)= 16 bags per cultivar hence (16 x 4) = 64 caring bags/ botanical. The splits had four 2kg caring bags hence (2x4) = 8 kg per split and (8x16) = 32kg/cultivar hence N =128kg. The caring bags were covered with a layer of the botanicals at a rate 100g, 150g, 200g, and untreated control respectively. Twenty (10♀ + 10♂) newly emerged moths were introduced inside the storage. We assessed for week one number of tubers infested and tunnels of PTM larvae, at week two for number of tubers infested and tunneling length. Week three number of tubers infested, tunneling length in tubers and number of second generation larva. Analysis was done by comparison of the means and there mean differences using R software. Results indicated use of 200g/ 2kg of the botanicals significantly reduced number of PTM larvae. Lantana camara was the most effective insecticide followed by Azadrachta indica compared to the controlled tubers. Thus the use of 200g of L. camara and Tigoni cultivar may be promising components of IPM strategies for reducing P. operculella population in potato fields and storage.

Vertical Migration of Adult Plecoptera and Trichoptera above Forested Headwater Streams.

Simple SummaryStream insects are essential components of aquatic and terrestrial ecosystems, but fewer studies have examined the terrestrial stage compared to the aquatic stage. Most adult stream insects are flight capable, which allows for short- and long-distance movements away from the stream channel into riparian or upland habitats. This study examined if adult stream insects migrate vertically into riparian forest canopies above the stream. We found a meaningful number of adult Trichoptera and Plecoptera in the forest canopy above the stream that was comparable to horizontal migrations. This result demonstrated that adult stream insects utilize riparian forest canopies and that numerous avenues for additional basic and applied research on terrestrial–aquatic linkages exist. Discovering how riparian canopy habitats are important for stream insects and how stream insects are linked to canopy ecosystems can inform restoration and conservation actions.Stream insects are essential components of aquatic and terrestrial ecosystem structure and function. Terrestrial stages are important components of terrestrial food webs, and flight-capable individuals are responsible for long-distance dispersal. Horizontal migrations by flying or crawling adults away from stream channels that link insects to riparian food webs and movements across catchment boundaries are well established through empirical research, but studies examining vertical migration of adult stream insects into forest canopies are generally lacking. This study focused on differences in adult Plecoptera and Trichoptera abundance at ground level versus the riparian canopy and differences in abundances among summer and autumn sampling periods to empirically demonstrate use of canopy ecosystems by stream insects. Malaise traps at ground level and canopy traps placed 8 to 10 m above the stream at four sites in the Mosquito Creek watershed (Pennsylvania) were used to examine vertical migration. Larval assemblages were collected and compared to adult assemblage to investigate patterns of local migration in the catchment. We found significantly more stream insects at ground level than in the forest canopy for Trichoptera, Plecoptera, and all individual plecopteran families, but a meaningful number of individuals were found in the riparian canopy. Canopy abundances were similar to abundances captured in adjacent ground-level habitats in other studies. Comparisons of adult and larval abundances among sites, taxa, and stages indicated site- and taxon-specific patterns for vertical movement into riparian canopies. Demonstrating that adult stream insects utilize riparian forest canopies indicates that riparian forest conservation should be prioritized over reforestation and that several potential research questions exist to inform riparian management.

Unraveling the World’s Longest Non-stop Migration: The Indian Ocean Crossing of the Globe Skimmer Dragonfly

Insect migration redistributes enormous quantities of biomass, nutrients and species globally. A subset of insect migrants perform extreme long-distance journeys, requiring specialized morphological, physiological and behavioral adaptations. The migratory globe skimmer dragonfly (Pantala flavescens) is hypothesized to migrate from India across the Indian Ocean to East Africa in the autumn, with a subsequent generation thought to return to India from East Africa the following spring. Using an energetic flight model and wind trajectory analysis, we evaluate the dynamics of this proposed transoceanic migration, which is considered to be the longest regular non-stop migratory flight when accounting for body size. The energetic flight model suggests that a mixed strategy of gliding and active flapping would allow a globe skimmer to stay airborne for up to 230–286 h, assuming that the metabolic rate of gliding flight is close to that of resting. If engaged in continuous active flapping flight only, the flight time is severely reduced to ∼4 h. Relying only on self-powered flight (combining active flapping and gliding), a globe skimmer could cross the Indian Ocean, but the migration would have to occur where the ocean crossing is shortest, at an exceptionally fast gliding speed and with little headwind. Consequently, we deem this scenario unlikely and suggest that wind assistance is essential for the crossing. The wind trajectory analysis reveals intra- and inter-seasonal differences in availability of favorable tailwinds, with only 15.2% of simulated migration trajectories successfully reaching land in autumn but 40.9% in spring, taking on average 127 and 55 h respectively. Thus, there is a pronounced requirement on dragonflies to be able to select favorable winds, especially in autumn. In conclusion, a multi-generational, migratory circuit of the Indian Ocean by the globe skimmer is shown to be achievable, provided that advanced adaptations in physiological endurance, behavior and wind selection ability are present. Given that migration over the Indian Ocean would be heavily dependent on the assistance of favorable winds, occurring during a relatively narrow time window, the proposed flyway is potentially susceptible to disruption, if wind system patterns were to be affected by climatic change.

A machine learning approach for classifying bird and insect radar echoes with S-band Polarimetric Weather Radar

AbstractThe S-bandWSR-88D weather radar is sensitive enough to observe biological scatterers like birds and insects. However, their non-spherical shapes and frequent collocation in the radar resolution volume create challenges in identifying their echoes. We propose a method of extracting bird (or insect) features by coherently averaging dual polarization measurements from multiple radar scans, containing bird (insect) migration. Additional features are also computed to capture aspect and range dependence, and the variation of these echoes over local regions. Next, ridge classifier and decision tree machine learning algorithms are trained, first only with the averaged dual pol inputs and then different combinations of the remaining features are added. The performance of all models for both methods, are analyzed using metrics computed from the test data. Further studies on different patterns of birds/insects, including roosting birds, bird migration and insect migration cases, are used to further investigate the generality of our models. Overall, the ridge classifier using only dual polarization variables was found to perform consistently well across all these tests. Our recommendation is that this classifier can be used operationally on the US Next-Generation Radars (NEXRAD), as a first step in classifying biological echoes. It would be used in conjunction with the existing Hydrometeor Classification Algorithm (HCA), where the HCA would first separate biological from non-biological echoes, then our algorithm would be applied to further separate biological echoes into birds and insects. To the best of our knowledge, this study is the first to train a machine learning classifier that is capable of detecting diverse patterns of bird and insect echoes, based on dual polarization variables at each range gate.

Resistance Evaluation of Dominant Varieties against Southern Rice Black-Streaked Dwarf Virus in Southern China.

Southern rice black-streaked dwarf virus (SRBSDV), a Fijivirus in the Reoviridae family, is transmitted by the white-backed planthopper (Sogatella furcifera, WBPH), a long-distance migratory insect, and presents a serious threat to rice production in Asia. It was first discovered in China’s Guangdong Province in 2001 and has been endemic in the south of China and north of Vietnam for two decades, with serious outbreaks in 2009, 2010, and 2017. In this study, we evaluated the resistance of 10 dominant rice varieties from southern China, where the virus overwinters and accumulates as a source of early spring reinfection, against this virus by artificial inoculation. The results showed that in all tested varieties there was no immune resistance, but there were differences in the infection rate, with incidence rates from 21% to 90.7%, and in symptom severity, with plant weight loss from 66.71% to 91.20% and height loss from 34.1% to 65.06%. Additionally, and valuably, the virus titer and the insect vector virus acquisition potency from diseased plants were significantly different among the varieties: an over sixfold difference was determined between resistant and susceptible varieties, and there was a positive correlation between virus accumulation and insect vector virus acquisition. The results can provide a basis for the selection of rice varieties in southern China to reduce the damage of SRBSDV in this area and to minimize the reinfection source and epidemics of the virus in other rice-growing areas.

Seasonal spatial dynamics of butterfly migration

AbstractUnderstanding the seasonal movements of migratory species underpins ecological studies. Several hundred butterfly species show migratory behaviour, yet the spatial pattern of these migrations is poorly understood. We developed climatic niche models for 405 migratory butterfly species globally to estimate patterns of seasonal movement and the distribution of seasonal habitat suitability. We found strong seasonal variation in habitat suitability for most migratory butterflies with >75% of pixels within their distributions showing seasonal switching in predicted occupancy for 85% of species. The greatest rate of seasonal switching occurred in the tropics. Several species showed extreme range fluctuations between seasons, exceeding 10‐fold for 53 species (13%) and more than 100‐fold for nine species (2%), suggesting that such species may be at elevated extinction risk. Our results can be used to search for the ecological processes that underpin migration in insects, as well as to design conservation interventions for declining migratory insects.

A Guide for Using Flight Simulators to Study the Sensory Basis of Long-Distance Migration in Insects.

Studying the routes flown by long-distance migratory insects comes with the obvious challenge that the animal’s body size and weight is comparably low. This makes it difficult to attach relatively heavy transmitters to these insects in order to monitor their migratory routes (as has been done for instance in several species of migratory birds. However, the rather delicate anatomy of insects can be advantageous for testing their capacity to orient with respect to putative compass cues during indoor experiments under controlled conditions. Almost 20 years ago, Barrie Frost and Henrik Mouritsen developed a flight simulator which enabled them to monitor the heading directions of tethered migratory Monarch butterflies, both indoors and outdoors. The design described in the original paper has been used in many follow-up studies to describe the orientation capacities of mainly diurnal lepidopteran species. Here we present a modification of this flight simulator design that enables studies of nocturnal long-distance migration in moths while allowing controlled magnetic, visual and mechanosensory stimulation. This modified flight simulator has so far been successfully used to study the sensory basis of migration in two European and one Australian migratory noctuid species.

An insect isoscape of UK and Ireland.

The study of insect migration is problematic due to the small size of insects. Stable isotope analysis can be used to elucidate movement, either by geographic assignment of location of a species, or by simply distinguishing migrant from resident populations. There are few isoscapes of any kind in the UK/Ireland available for interrogation. Thus, I have measured stable isotope ratios (of H, C, N and S) of 299 individuals of the non-migratory Brimstone moth (Opisthograptis luteolata) collected from 93 locations around the UK and Ireland by citizen scientists. After removing lipids, stable isotope ratios were measured by continuous flow isotope ratio mass spectrometry, using either a conventional elemental analyser (C, N and S) or a high-temperature, thermal conversion elemental analyser in reductive mode. Maps (isoscapes) were constructed that illustrate the stable isotope spatial distribution of this insect. These are the first isoscapes of H, C, N and S of biological samples covering both UK and Ireland. The insect isoscape patterns can be explained from what we know of moth diet, climate and geology. Sulfur isotopes may be of particular use for distinguishing individuals from areas of unique geology. Isoscape patterns may (with care) predict isotope compositions of other, herbivorous, non-aquatic, chitinous taxa. Such isoscapes, when extended beyond the UK and Ireland, would provide a useful tool to elucidate insect migration.

Effect of organic farming on the ladybird beetle diversity (Coleoptera: Coccinellidae)

Coccinellidae perform the function of biological control of pests in nature, they eat aphids and other insects, which is important in organic agriculture. The aim of the work was to establish the distribution and species composition of the family Coccinellidae in the organic agro-landscape. The research was conducted at the Skvyra research station of organic production (Kyiv region, Ukraine). Insects were collected by entomological mowing with a net in four stages of plant development. The organic agro-landscape included crops of buckwheat, oats, soybeans and winter wheat. Data from neighbor conventional soybean and winter wheat ecosystems were used for comparison. The agroecosystems of these crops, which included felds, ecotones ”feld – feld protective forest shelter belt”, feld protective forest shelter belts, were studied. The study identifed 10 species of the family Coccinellidae, the number of species ranged from 1 to 89/100 waves, the largest in the ecosystem of organic winter wheat. H. axiridis belonged to the recedents and was found in fve agroecosystems in the amount of 1-7 individuals / 100 waves. The most common species were C. septempunctata, T. sedecimpunctata and larvae of Coccinellidae, which were eudominant in the organic agro-landscape. Species Vibidia sp. was found only in organic agroecosystems of buckwheat and oats. The variety of ladybugs in organic winter wheat was higher than in conventional. Organic soybeans, in contrast, had less variety of Coccinellidae than conventional soybeans, as confrmed by cluster analysis. Species richness in crop ecosystems ranged from 3 to 8 in different study periods. High correlations of insect numbers were found between felds, ecotones and forest shelter belts, as well as between neighbor ecotones and neighbor forest belts, which indicates the migration of insects between these areas. Thus, the diversity and prevalence of Coccinellidae in the organic agro-landscape, compared to the traditional one, has been established. Key words: ladybugs, organic farming, agrolandscape, agroecosystem, crops, species.

Digital Detection and Tracking of Tiny Migratory Insects Using Vertical-Looking Radar and Ascent and Descent Rate Observation

Vertical-looking radar (VLR) is a significant milestone in the development of insect radars with the capability of detecting the behavior of migratory insects and their biological parameters. In current VLRs, high-speed continuous sampling and long-time integration can barely be performed simultaneously, leading to a low detection probability for tiny insects (weight < 10 mg). Based on the large amount of data acquired by our developed high-range resolution insect radar, the insect echo signals and vertical motion characteristics are initially analyzed and demonstrate that the linear-motion mode is dominant in insect migration; also, the echo signal power of most insects follows the gamma distribution. Based on these characteristics, a long-time integration and detection method for detecting migratory insects, especially tiny targets from echo signals that often dip below the noise level, is proposed. The radial target velocity is also measured as one of the output parameters. The theoretical derivation and optimal choice of detection thresholds are also presented. Simulation and experimental results demonstrate that the proposed method exhibits better insect detection performance and effectively increases the detection range compared with conventional methods. In addition, the measured target velocity can be directly applied to current continuous-sampling VLRs for the ascent and descent rate analysis. Many typical insect migration phenomena have been detected effectively utilizing our developed VLR, and the measured ascent and descent rates of insects agree well with typical take-off, cruising, and landing behaviors. This is the first reported successful VLR application on take-off and landing behaviors of migratory tiny and dense insects.

Migration in butterflies: a global overview.

Insect populations including butterflies are declining worldwide, and they are becoming an urgent conservation priority in many regions. Understanding which butterfly species migrate is critical to planning for their conservation, because management actions for migrants need to be coordinated across time and space. Yet, while migration appears to be widespread among butterflies, its prevalence, as well as its taxonomic and geographic distribution are poorly understood. The study of insect migration is hampered by their small size and the difficulty of tracking individuals over long distances. Here we review the literature on migration in butterflies, one of the best-known insect groups. We find that nearly 600 butterfly species show evidence of migratory movements. Indeed, the rate of 'discovery' of migratory movements in butterflies suggests that many more species might in fact be migratory. Butterfly migration occurs across all families, in tropical as well as temperate taxa; Nymphalidae has more migratory species than any other family (275 species), and Pieridae has the highest proportion of migrants (13%; 133 species). Some 13 lines of evidence have been used to ascribe migration status in the literature, but only a single line of evidence is available for 92% of the migratory species identified, with four or more lines of evidence available for only 10 species - all from the Pieridae and Nymphalidae. Migratory butterflies occur worldwide, although the geographic distribution of migration in butterflies is poorly resolved, with most data so far coming from Europe, USA, and Australia. Migration is much more widespread in butterflies than previously realised - extending far beyond the well-known examples of the monarch Danaus plexippus and the painted lady Vanessa cardui - and actions to conserve butterflies and insects in general must account for the spatial dependencies introduced by migratory movements.