Indirect transfer of pyriproxyfen to European honeybees via an autodissemination approach

The frequency of arboviral disease epidemics is increasing and vector control remains the primary mechanism to limit arboviral transmission. Container inhabiting mosquitoes such as Aedes albopictus and Aedes aegypti are the primary vectors of dengue, chikungunya, and Zika viruses. Current vector control methods for these species are often ineffective, suggesting the need for novel control approaches. A proposed novel approach is autodissemination of insect growth regulators (IGRs). The advantage of autodissemination approaches is small amounts of active ingredients compared to traditional insecticide applications are used to impact mosquito populations. While the direct targeting of cryptic locations via autodissemination seems like a significant advantage over large scale applications of insecticides, this approach could actually affect nontarget organisms by delivering these highly potent long lasting growth inhibitors such as pyriproxyfen (PPF) to the exact locations that other beneficial insects visit, such as a nectar source. Here we tested the hypothesis that PPF treated male Ae. albopictus will contaminate nectar sources, which results in the indirect transfer of PPF to European honey bees (Apis mellifera). We performed bioassays, fluorescent imaging, and mass spectrometry on insect and artificial nectar source materials to examine for intra- and interspecific transfer of PPF. Data suggests there is direct transfer of PPF from Ae. albopictus PPF treated males and indirect transfer of PPF to A. mellifera from artificial nectar sources. In addition, we show a reduction in fecundity in Ae. albopictus and Drosophila melanogaster when exposed to sublethal doses of PPF. The observed transfer of PPF to A. mellifera suggests the need for further investigation of autodissemination approaches in a more field like setting to examine for risks to insect pollinators.

First Report of Pestalotiopsis chamaeropis Causing Leaf Spot on Eurya nitida in China

Eurya nitida Korth. belonging to the family Theaceae is an evergreen shrub or small tree and is usually used as a very important ornamental tree and nectar source plant (Khan et al. 1992; Ma et al. 2013). It also has high medicinal values with the treatment of rheumatoid arthritis, diarrhea, innominate inflammatory of unknown origin, ulcer fester and traumatic hemorrhage (Park et al. 2004). In October 2020, symptoms of leaf spot were observed on E. nitida in Meiling Scenic Spot of Nanchang, Jiangxi Province, China (28.78°N, 115.83°E). We surveyed about 300 m2 of the mountain area which holds about 100 trees of E. nitida scattered naturally near the waterside or regularly planted on either side of the mountain road. Most of the infected plants were observed from humid environments or waterside, with 15~20% disease incidence, and the disease severity on a plant basis was determined to be 25% to 30%, depending on the field. Sixty infected leaves were collected from 20 individual trees which have the same symptoms. The symptoms on infected leaves appeared as tiny circular spots that gradually enlarged into brown circular necrotic lesions and then became a light gray with brown borders and black acervuli at the later stages of the disease. Ten leaves of infected tissues randomly selected from collected sixty infected leaves were cut into 4 mm2 pieces, and surface disinfected with 75% ethanol for 30s and 1% hypochlorite for 1 min, rinsed three times with sterile water, plated on potato dextrose agar (PDA), and incubated at 25°C in the dark for 5 to 7 days. Five isolates with similar morphological characteristics were obtained. Colonies developed copious white aerial mycelium covering the entire Petri dish area after 7 to 10 days. Conidiogenous cells were discrete, hyaline, and smooth. Conidia were fusiform, ellipsoid, 4-euseptate and ranged from 21.86 to 29.80 × 5.95 to 9.80 µm. Apical cells were hyaline with 2 to 3 unbranched, tubular apical appendages (mostly 3); basal cell was hyaline, obconic with a truncate base; three median cells doliiform to subcylindrical, brown. The morphological characteristics of all isolates matched features described for Pestalotiopsis chamaeropis Maharachch., K.D. Hyde & Crous (Maharachchikumbura et al. 2014). Two single representatives (JAUCC L001-1 and JAUCC L002) were used for molecular identification, which were verified based on the amplification of DNA sequences of internal transcribed spacer region (ITS) gene and translation elongation factor 1 alpha (TEF1-α) gene, using the primers ITS4/ITS5 (White et al. 1990) and EF1-526F/EF1-1567R (Rehner and Buckley 2005), respectively. The sequenced loci (GenBank accession nos. ITS: MW845761, MW828589 and TEF1-α: MW838967, MZ292464) exhibited over 99% homology with P. chamaeropis strain CBS 186.71 in GenBank (GenBank accession nos. KM199326 and KM199473), confirming the morphological identification. Phylogenetic reconstruction was generated by using the maximum likelihood (ML) method based on the Kimura 2-parameter model, with bootstrap nodal support for 1000 pseudoreplicates in MEGA software, version 7.0. The result showed that our isolates were clustered together with P. chamaeropis at 99% bootstrap values. Based on morphological characteristics and molecular phylogenetic analysis, the isolates were identified as P. chamaeropis. The pathogenicity of one representative isolate (JAUCC L001-1) was tested indoor by inoculating the top leaves of six healthy E. nitida plants. Three plants with three leaves were punctured with flamed needles and sprayed with a conidial suspension (1 × 106 conidia/ml), and other three plants wounded inoculated with mycelial plugs (5 × 5 mm3). Mock inoculations were used as controls with sterile water and non-infested PDA plugs on three leaves each. Treated plants were incubated in an artificial climate box with high relative humidity at 25 °C. After 10 days, symptoms on all wounded inoculated plants were similar to those previously observed with distinct tiny circular spots, whereas no symptoms appeared on inoculated plants. Pestalotiopsis chamaeropis was re-isolated from symptomatic tissues but not from the mock-inoculated plants, and its identity was confirmed by morphological characteristics and molecular data, which confirmed Koch's postulates. Pestalotiopsis chamaeropis was previously reported as the causal agent of leaf blight diseases on Camellia sinensis in China (Chen et al. 2020), Pieris japonica in Japan (Nozawa et al. 2019) and Prostanthera rotundifolia in Australia (Azin et al. 2015). To our knowledge, this is the first report of P. chamaeropis causing a leaf spot disease on E. nitida in China, and this disease may be more widespread than the sampled location. This finds is beneficial to the better protection of E. nitida, a widespread medicinal and nectar source plant with high economic value.

Melittopalynological studies of Apis dorsata honey samples from Kolar District, Karnataka, India

Honeybees, while foraging for nectar on flowers, also gather some pollen which retains in the honey even after extraction. Pollen grains are the essential tools in the analysis of honey. The aim of the present report was to find the Apis dorsata honey floral resources in Kolar district state Karnataka. In the present study, the pollen content of 28 A. dorsata honey samples were collected from 5 different locations of Kolar district, Karnataka, India. Samples were subjected to Melittopalynological studies to identify their honey plant resources and colour, optic density and collection places were documented. A wide variety of pollen types represent their plant sources and their frequency classes were recognized in each honey sample. Among 28 honey samples analysed, 10 samples were identified as multifloral, 18 unifloral with predominant pollen types such as Syzygium cumini, Pongamia pinnata, Eucalyptus sp, Guizotia abyssinica, Psidium guajava and Coriandrum sativum, each count was found above 45%. Pollen spectra indicated a total of 56 pollen types belonging to 27 plant families. Fabaceae was represented as the largest family with 14 species contributing honey production. Among the habit, tree was dominant with 51.78%, followed by herbs (32.14%) and shrubs (16.07%). The economic importance of identified plants with apiculture importance was categorized as medicinal, ornamental, vegetable, timber and oil yielding, weeds, fruits and nuts. A. dorsata depends on wild trees and cultivated plants bloom throughout the year as pollen and nectar source. From the results, it is evident that there is a lot of potential in establishing beekeeping industries in the study area.

Nectar Uptake of a Long-Proboscid Prosoeca Fly (Nemestrinidae)—Proboscis Morphology and Flower Shape

Several Prosoeca (Nemestinidae) species use a greatly elongated proboscis to drink nectar from long-tubed flowers. We studied morphological adaptations for nectar uptake of Prosoecamarinusi that were endemic to the Northern Cape of South Africa. Our study site was a small isolated area of semi-natural habitat, where the long-tubed flowers of Babiana vanzijliae (Iridaceae) were the only nectar source of P. marinusi, and these flies were the only insects with matching proboscis. On average, the proboscis measured 32.63 ± 2.93 mm in length and less than 0.5 mm in diameter. The short labella at the tip are equipped with pseudotracheae that open at the apical margin, indicating that nectar is extracted out of the floral tube with closed labella. To quantify the available nectar resources, measurements of the nectar volume were taken before the flies were active and after observed flower visits. On average, an individual fly took up approximately 1 µl of nectar per flower visit. The measured nectar quantities and the flower geometry allowed estimations of the nectar heights and predictions of necessary proboscis lengths to access nectar in a range of flower tube lengths.

Native and Invasive Ants Affect Floral Visits of Pollinating Honey Bees in Pumpkin Flowers (Cucurbita Maxima)

Global pollinator decline is a major concern. Several factors – climate change, land-use change, the decline of flowers, pesticide use, invasive species – have been suggested as the reasons. The effect of ants on flowers, despite being a potential reason, received less attention. The consequences of ants being attracted to nectar sources in plants vary depending upon factors like the position of the nectar source, the identity of ants, and other mutualists interacting with the plants. We studied the interaction between floral ants and pollinators in Cucurbita maxima and compared the competition exerted by native and invasive ants on the pollinator with the hypothesis that the invasive ants exacerbate more interference competition for pollinators than native ants. The pollinator’s choice, visitation rate and time spent/visit were assessed. Regardless of species and nativity ants negatively influenced all the pollinator visitation traits, such as visitation rate and duration spent on flowers. The invasive ants exerted a higher interference competition on the pollinators than native ants did. Ants despite performing pollination in flowers with generalist pollination syndrome, can be a threat for plant-pollinator mutualism in specialists like monoecious plants. A better understanding of factors influencing pollination will help in implementing better management practices.

Cirsium wallichii DC. (Asteraceae): a key nectar source of butterflies

Butterfly diversity and abundance depend on the diversity of foraging resources and nectar characteristics. Several wild plants of the family Asteraceae often considered as weeds, are important nectar sources for butterflies. The present communication reports Cirsium wallichii as a key nectar source for a large number of butterfly species during the summer season in Benog Wildlife Sanctuary, Mussoorie, western Himalaya. Of the total recorded species of butterflies (62), a maximum species (22) belongs to the Nymphalidae family followed by Hesperiidae (13), and Lycaenidae (11) that visits C. wallichii. Therefore, it is suggested that Cirsium wallichii has an important role in sustaining butterfly diversity. Keywords: Mussoorie, Lepidoptera, .

The Migratory Beekeeping Routing Problem: Model and an Exact Algorithm

Apiculture has gained worldwide interest because of its contributions to economic incomes and environmental conservation. In view of these, migratory beekeeping, as a high-yielding technique, is extensively adopted. However, because of the lack of an overall routing plan, beekeepers who follow the experiential migratory routes frequently encounter unexpected detours and suffer losses when faced with problems such as those related to nectar source capacities and the production of bee products. The migratory beekeeping routing problem (MBRP) is proposed based on the practical background of the commercial apiculture industry to optimize the global revenue for beekeepers by comprehensively considering nectar source allocation, migration, production and sales of bee products, and corresponding time decisions. The MBRP is a new variant of the vehicle routing problem but with significantly different production time decisions at the vertices (i.e., nectar sources). That is, only the overlaps between residence durations and flowering periods generate production benefits. Different sales visits cause different gains from the same products; in turn, these lead to different production time decisions at previously visited nectar source locations and even change the visits for production. To overcome the difficulty resulting from the complicated time decisions, we utilize the Dantzig–Wolfe decomposition method and propose a revised labeling algorithm for the pricing subproblems. The tests, performed on instances and a real-world case, demonstrate that the column generation method with the revised labeling algorithm is efficient for solving the MBRP. Compared with traditional routes, a more efficient overall routing schedule for migratory beekeepers is proposed. Summary of Contribution. Based on the practical background of commercial apiculture industry, this paper proposes a new type of routing problem named the migratory beekeeping routing problem (MBRP), which incorporates the selection of productive nodes and sales nodes as well as the production time decision at the productive nodes on a migratory beekeeping network. To overcome the difficulty resulting from the complicated time decisions, we utilize the Dantzig–Wolfe decomposition method and propose a revised labeling algorithm for the pricing subproblems. The tests, performed on instances and a real-world case, demonstrate that the column generation method with the revised labeling algorithm is efficient for solving the MBRP. Compared with traditional routes, a more efficient overall routing schedule for migratory beekeepers is proposed. Therefore, this paper is congruent with, and contributes to, the scope and mission of INFORMS Journal on Computing, especially the area of Network Optimization: Algorithms & Applications.

Integration of NDVI Imagery and Crop Coverage Registration System for Apiary Schedule

Beekeepers need to establish migratory apiaries to benefit from pollen and nectar source plants as in order to increase honey yield. Thus, following the flowering seasons of honey source plants has vital importance when deciding the route of migration. In this study, MODIS imagery was used to generate weekly NDVI data between 1st April to 31st August 2018, when beekeeping activities start and end in the study area. Although MODIS images have high temporal resolution, low spatial resolution (250 meters) makes them insufficient when deciding the crop types and plants. While detecting plants in natural plant areas requires high spatial resolution NDVI, Crop Coverage Registration System (CCRS) parcel-based crop coverage records can enrich the NDVI data without increasing spatial resolution in agricultural lands. Thus, the CCRS data were integrated with NDVI images for migratory beekeeping in agricultural areas as an innovation. To generate both high temporal and spatial resolution, NDVI and CCRS data were integrated together with a beekeeping suitability map to generate the apiary schedule. The results were verified with 176 existing apiary locations and production dates retrieved from field studies which revealed the existence of three seasons in the study area as early and late apiaries (in natural plant areas) and apiaries in agricultural lands. Accuracy analysis showed that 82% of the apiaries intersected with suitable locations and that apiaries in agricultural areas were detected five days earlier than in field studies and obtained more accurately than natural plant apiaries.