Wind-related orientation patterns in diurnal, crepuscular and nocturnal high-altitude insect migrants

Most insect migrants fly at considerable altitudes (hundreds of meters above the ground) where they utilize fast-flowing winds to achieve rapid and comparatively long-distance transport. The nocturnal aerial migrant fauna has been well studied with entomological radars, and many studies have demonstrated that flight orientations are frequently grouped around a common direction in a range of nocturnal insect migrants. Common orientation typically occurs close to the downwind direction (thus ensuring that a large component of the insects' self-powered speed is directed downstream), and in nocturnal insects at least, the downwind headings are seemingly maintained by direct detection of wind-related turbulent cues. Despite being far more abundant and speciose, the day-flying windborne migrant fauna has been much less studied by radar; thus the frequency of wind-related common orientation patterns and the sensory mechanisms involved in their formation remain to be established. Here, we analyze a large dataset of >600,000 radar-detected "medium-sized" windborne insect migrants (body mass from 10 to 70 mg), flying hundreds of meters above southern UK, during the afternoon, in the period around sunset, and in the middle of the night. We found that wind-related common orientation was almost ubiquitous during the day (present in 97% of all “migration events” analyzed), and was also frequent at sunset (85%) and at night (81%). Headings were systematically offset to the right of the flow at night-time (as predicted from the use of turbulence cues for flow assessment), but there was no directional bias in the offsets during the day or at sunset. Orientation "performance” significantly increased with increasing flight altitude throughout the day and night. We conclude by discussing sensory mechanisms which most likely play a role in the selection and maintenance of wind-related flight headings

Predicting insect migration density and speed in the daytime convective boundary layer

Insect migration needs to be quantified if spatial and temporal patterns in populations are to be resolved. Yet so little ecology is understood above the flight boundary layer (i.e. >10 m) where in north-west Europe an estimated 3 billion insects km(-1) month(-1) comprising pests, beneficial insects and other species that contribute to biodiversity use the atmosphere to migrate. Consequently, we elucidate meteorological mechanisms principally related to wind speed and temperature that drive variation in daytime aerial density and insect displacements speeds with increasing altitude (150-1200 m above ground level). We derived average aerial densities and displacement speeds of 1.7 million insects in the daytime convective atmospheric boundary layer using vertical-looking entomological radars. We first studied patterns of insect aerial densities and displacements speeds over a decade and linked these with average temperatures and wind velocities from a numerical weather prediction model. Generalized linear mixed models showed that average insect densities decline with increasing wind speed and increase with increasing temperatures and that the relationship between displacement speed and density was negative. We then sought to derive how general these patterns were over space using a paired site approach in which the relationship between sites was examined using simple linear regression. Both average speeds and densities were predicted remotely from a site over 100 km away, although insect densities were much noisier due to local 'spiking'. By late morning and afternoon when insects are migrating in a well-developed convective atmosphere at high altitude, they become much more difficult to predict remotely than during the early morning and at lower altitudes. Overall, our findings suggest that predicting migrating insects at altitude at distances of ≈ 100 km is promising, but additional radars are needed to parameterise spatial covariance

Evidence for facultative migratory flight behavior in Helicoverpa armigera (Noctuidae: Lepidoptera) in India

Despite its deleterious impact on farming and agriculture, the physiology and energetics of insect migration is poorly understood due to our inability to track their individual movements in the field. Many insects, e.g. monarch butterflies, Danaus plexippus (L.), are facultative migrants. Hence, it is important to establish whether specific insect populations in particular areas migrate. The polyphagous insect, Helicoverpa armigera (Hubner), is especially interesting in this regard due to its impact on a variety of crops. Here, we used a laboratory based flight mill assay to show that Helicoverpa armigera populations clearly demonstrate facultative migration in South India. Based on various flight parameters, we categorized male and female moths as long, medium or short distance fliers. A significant proportion of moths exhibited long-distance flight behaviour covering more than 10 km in a single night, averaging about 8 flight hours constituting 61% flight time in the test period. The maximum and average flight speeds of these long fliers were greater than in the other categories. Flight activity across sexes also varied; male moths exhibited better performance than female moths. Wing morphometric parameters including forewing length, wing loading, and wing aspect ratio were key in influencing long-distance flight. Whereas forewing length positively correlated with flight distance and duration, wing loading was negatively correlated

Impact of weather parameters on the seasonal incidence of Helopeltis antonii (Miridae: Hemiptera) on neem

Neem (Azadirachta indica A. Juss.), known for its extensive therapeutic properties, is susceptible to various pests, notably the tea mosquito bug (Helopeltis antonii Signoret). This study investigates the seasonal incidence of H. antonii on neem across different age classes and explores the correlation between meteorological factors and pest infestation. The survey monitored sixty neem trees categorized into three age groups: Category I (less than 2 years), Category II (2-6 years), and Category III (more than 6 years). Peak nymphal populations occurred in November for Categories I (12.70 nymphs/branch) and III (13.35 nymphs/branch), while Category II peaked in October (12.80 nymphs/branch). Complete drying (100% infestation) was observed from late January to mid-February for Categories I and III, and from early December to mid-February for Category II. Correlation analysis revealed a significant negative relationship between infestation levels and minimum temperature, while maximum relative humidity and sunshine hours positively correlated with pest abundance. Multi-linear regression indicated that over 90% of the variation in infestation rates could be attributed to meteorological factors. This study highlights the persistent threat of H. antonii to neem trees, regardless of age and is the first study to look at the seasonal incidence of H. antonii on different age classes of neem. Further research is required to assess the long-term implications of climate variability on H. antonii dynamics and its broader ecosystem effects.

MOOC on Integrated Pest Management (IPM): A New Online Venture in Agricultural Education System

The landscape of agriculture is changing rapidly due to include agribusiness in supply­chain operations and management. As a result, there is an absolute necessity to empower farmers, women and youth in terms of livelihood and entrepreneurship skills. Innovations in ICT which are playing an important role in bridging the gap could be successfully employed for this purpose. Looking into its importance National Academy of Agricultural Science (NAAS), New Delhi has brought out a policy paper on ‘MOOC for capacity building in Indian agriculture: Opportunities and challenges’ in January 2015. The policy paper emphasises the strength and potential of MOOC in reaching out larger section of the students/faculty/extension personnel in delivering the goods. Encouraged by the policy decision, MOOCs in some of the agricultural subjects were designed and offered in collaboration with NPTEL and IITK of which, IPM was one among them. // Paper ID 47

A Comprehensive Survey on Human Action Recognition

The present The present situation is having many challenges in security and surveillance of Human Action recognition (HAR). HAR has many fields and many techniques to provide modern and technical action implementation. We have studied multiple parameters and techniques used in HAR. We have come out with a list of outcomes and drawbacks of each technique present in different researches. This paper presents the survey on the complete process of recognition of human activity and provides survey on different Motion History Imaging (MHI) methods, model based, multiview and multiple feature extraction based recognition methods.</jats:p

Time/height plots for numbers of insects recorded by a VLR at Cholbolton, Hampshire, UK.

<p>The colour scale bar refers to the number of individually-resolvable insects detected by the radar at each sampling height in each 5-minute period. The X-axis shows time of day (GMT), and the ‘early’ and ‘late’ analysis periods are indicated. A. Insect densities on a warm day (05 September 2004), when air temperatures at 10 m, 150 m and 600 m were 24.7°C, 22.8°C and 18.5°C respectively. B. Insect densities on a much cooler day (15 September 2004), when air temperatures at 10 m, 150 m and 600 m were 15.4°C, 13.2°C and 8.8°C respectively. Substantial density was constrained to time-periods and altitudes where air temperatures were relatively warm. Air temperatures were obtained from the UK Met Office's ‘Unified Model’ <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054202#pone.0054202-Wood1" target="_blank">[14]</a>.</p

Lorenz curves for insect displacement speeds and densities by period.

<p>Lorenz curves for insect displacement speeds and densities by period.</p