The Use of Honeybee Hives May Boost Yields of Some Crops in Nepal

Many pollination-dependent crops worldwide need bees for the highest productivity. If the crops are not pollinated, a pollination deficit will result. Consequently, low yields of fruit set and seed set of cultivated plants may be expected. Here, we evaluated how pollination with honeybee (Apis mellifera) hives may affect the production of the bittergourd (Momordica charantia), buckwheat (Fagopyrum esculentum), and mustard (Brassica campestris) in tons or quintal per hectare in Nepal. Our experimental design involved three treatments in blocks within selected areas: (i) the effect of the honeybees alone (caged with beehives), (ii) free insect access under natural field conditions, and (iii) blocks restraining insect access (caged without beehives). We also assessed the flower visiting insects within crops using pan traps and identifying insect orders. We found that the productivity of bittergourd, buckwheat, and mustard significantly increased in the treatments with beehives inside the cage. To a lesser extent, the treatment with free access to the flying insects enhanced the production of the selected crops. Proportionally, Hymenoptera (mainly bees) was the most common taxon within bittergourd, buckwheat, and mustard crops, followed by Diptera and Lepidoptera. Hence, the provision of beehives in cultivated areas such as those evaluated here could be considered as a complementary strategy for supporting the long-term productivity of these crops in Nepal.

Butterfly Diversity and Abundance in the Middle Afromontane Area of Northwestern Ethiopia

Butterflies are good indicators of environmental health, and they play a critical role in the food chain. Butterfly diversity and abundance were studied for the first time at three forests and their surrounding habitats in northwestern Ethiopia, a borderline ecosystem between the subtropical savannah and the Ethiopian highlands (Afromontane). Butterfly species richness and abundance were assessed using transects between October 2018 and June 2019. Data were analyzed using analysis of variance, correlation and regression analysis, diversity indices, ordination analysis, cluster analysis, and rarefaction curves. A total of 27,568 butterflies were recorded that belonged to three families, five subfamilies, and eight genera. The forest habitat had more butterfly taxa (abundance and diversity) than other habitats. Belenois spp. and Mylothris agathina were the most abundant in all three study locations. Species common to all study areas include Belenois aurota, Belenois raffrayi, Mylothris agathina, Eronia leda, Junonia terea elgiva, and Phalanta eurytis neuritis. Forest edge and woody forest habitats were the richest in terms of both number of species and number of individuals. Equitability (Pielou's index) showed equal distribution of the species, i.e., 0.8 to 0.9, except at the open grassland at Tara Gedam (0.3). Margalef's index varied between habitats and locations showing differences in species richness (from 0.25 at the woody forest of Mount Bezawit to 0.86 at the forest edge of Tara Gedam). Ordination analyses also showed that associations existed between habitats, locations, and dates of sampling. Rarefaction curves rose quickly at the forest edge and woody forest habitats compared to other forests. The cluster analysis discriminated the different habitats. Populations declined during the dry season (December to April). In conclusion, butterfly species diversity and abundance varied with respect to habitat and sampling date (season), although less diverse than other regions in the country where natural forests still widely exist. Butterfly species must be regularly monitored, and their habitats must be preserved for the health of the entire ecosystem.

Efficacy of Aqueous Extracts from Syzygium aromaticum, Tephrosia vogelii, and Croton dichogamus against Myzus persicae on Brassica oleracea in Northern Tanzania

The effectiveness of 1, 5, and 10% w/v of aqueous extracts of Croton dichogamus, Tephrosia vogelii, and Syzygium aromaticum and their mixture (2.5 and 5%) was evaluated against Myzus persicae on Brassica oleracea under field conditions. The synthetic chemical insecticide, chlorpyrifos, was used as positive control, and water and water plus soap were used as negative controls. Aqueous extracts significantly ( P ≤ 0.05 ) lowered M. persicae population compared with negative controls. The 5% of the aqueous extract from mixed plants and 10% of each plant used in this study significantly ( P ≤ 0.01 ) reduced aphid, M. persicae population comparable to chlorpyrifos in 2019 and 2020. However, the 1 and 5% concentrations of aqueous extracts of C. dichogamus, T. vogelii, and S. aromaticum and 2.5% of aqueous extracts from the mixed plants significantly lowered the population of M. persicae compared with negative controls in 2019 and 2020 wet seasons. The weekly observations revealed that, at weeks 1, 2, 3, 4, and 5 after application of treatments, the population of M. persicae differed significantly ( P ≤ 0.05 ). Also, the aqueous extracts from the mixed plants at 5% concentrations significantly ( P ≤ 0.01 ) reduced M. persicae population as compared with other treatments. It was as effective as synthetic chemical pesticide (chlorpyrifos). Also, 1 and 5% of C. dichogamus, T. vogelii, and S. aromaticum and the 2.5% of aqueous extracts from the mixed plants significantly reduced the population of M. persicae for all 6 weeks of study compared with negative controls. Therefore, these pesticidal plants can be recommended to smallholder farmers for the control of M. persicae in B. oleracea crops.

The Effect of Breeding Habitat Characteristics on the Larval Abundance of Aedes Vector Mosquitoes (Diptera: Culicidae) in Three Localities, Galle District, Sri Lanka

Dengue has become a national burden in Sri Lanka, and the understanding of breeding ecology of vectors, Aedes aegypti Linnaeus and Aedes albopictus Skuse, is the most effective way to control the disease. The present study was undertaken to investigate the relative larval abundance of Ae. aegypti and Ae. albopictus in different types and characteristics of containers in three selected localities in Galle district, Sri Lanka. Totally, 550 containers were positive for both Ae. aegypti and Ae. albopictus larvae. Aedes albopictus showed the high larval abundance in all studied sites. The larval abundance of artificial containers (90.57%) was high than that of natural containers (9.43%) for both Aedes spp. ( P < 0.05 ). The breeding preference for A. aegypti was high in tires (rubber) (17.82%), while plastic cups (28.00%) were the most preferable container type for Ae. albopictus. Dark color containers than light color containers ( P < 0.05 ) and containers with leaf litter accumulated as detritus ( P < 0.05 ) showed high relative larval abundance for both Aedes species. Containers with 50–100 ml volume of water showed the highest relative abundance of both Ae. aegypti (29.28%) and Ae. albopictus (41.79%) ( P > 0.05 ). The high larval abundance of Aedes recorded in ground level containers (1–5 cm) and their abundance decreased significantly with the increasing of height where containers were found (1–20 cm) ( P < 0.05 ). The significantly high relative abundance was observed with the increase of the shady level for Ae. aegypti (57.34%) and Ae. albopictus (61.32%) ( P < 0.05 ). This knowledge will be helpfull to implement dengue surveillance programs in the area.

Toxicity and Oviposition Deterrent Activities of Thyme Essential Oils against Anopheles arabiensis

Background. Malaria is one of the deadliest mosquito-borne diseases in sub-Saharan Africa and Ethiopia. Owing to their costs and environmental issues, synthetic insecticides are poor choices to control mosquitoes. Plant-based products can be considered as safe and biodegradable alternatives. The present study aimed to test the toxicity and oviposition deterrent activities of Thymus serrulatus and Thymus schimperi essential oils (EOs) against Anopheles arabiensis. Methods. Thyme EOs were extracted by hydrodistillation using the Clevenger-type apparatus. They were named Tar, Ala, and Yil after the areas of thyme collection Tarmaber, Alamata, and Yilmana Densa, respectively. Laboratory-based tests were used to determine the larvicidal, adulticidal, oviposition deterrent, and half lethal dose (LD50) of each EO. Results. The concentrations of 100 μl/L and 50 μl/L resulted in complete mortalities of larvae and adults, respectively, for all the three Eos considered. The EOs exhibited high repellency with oviposition activity index of −1 (OAI = −1) at concentrations of 50 μl/L (Tar), 100 μl/L (Ala), and 200 μl/L (Yil). Conclusions. The EOs of T. serrulatus and T. schimperi were effective against larvae and adult mosquitoes at small doses and resulted in oviposition deterrence at doses from 50 to 200 μl/L. Thus, these EOs are promising mosquitocides and oviposition deterrents. But, further tests both in the presence of already known and effective deterrents and field trials are required.

Chemical Composition and Larvicidal Activity of Lavandula angustifolia Subsp. angustifolia and Lavandula dentata Spp. dentata Essential Oils against Culex pipiens Larvae, Vector of West Nile Virus

The Culex pipiens mosquito (Diptera: Culicidae) is highly suspected to be the vector responsible for the spread of several parasitic and viral diseases. The use of synthetic insecticides is generally the preferred method of controlling these mosquitoes’ proliferation. However, it has led to resistance problems in target mosquitoes and environmental damage. Hence, diverse plant extracts could be considered as an alternative and potential source as mosquito control agents. In this study, essential oils of Lavandula angustifolia subsp. angustifolia and Lavandula dentata spp. dentata that are growing in Morocco were examined for their insecticidal effects on Culex pipiens larvae. The bioassay was performed according to a methodology inspired by the standard protocol of the World Health Organization. The mortality rate was determined after 24 hours of exposure, and probit regression analysis was used to calculate LC50 and LC90. The chemical analysis revealed that the principal compounds of L. angustifolia subsp. essential oils include linalool, linalyl acetate, geraniol, lavandulyl acetate, camphor, β-caryophyllene, terpinen-4-ol, β-myrcene, and 1,8-cineole, while the essential oil of L. dentata spp. was mainly composed of 1,8-cineole, camphor, α-pinene, trans-pinocarveol, linalool, and borneol. These volatile compounds have shown a toxic effect against Culex pipiens larvae, with lethal concentrations LC50 and LC90 being, respectively, 140 µg/ml and 450 µg/ml, for the L. angustifolia subsp. essential oil. Meanwhile, they were estimated at 2670 µg/ml and 7400 µg/ml, respectively, for the L. dentata spp. essential oil. These results suggest using essential oils of two species of Lavandula to control the Culex pipiens mosquito. It could be useful for the study of new natural larvicidal compounds.

A Description and Examination of Fluorescence in Nine North American Firefly Species (Coleoptera: Lampyridae)

Fluorescence across the family Lampyridae has been documented sporadically but not comprehensively in formal research. Fireflies (Coleoptera: Lampyridae), best known for their bioluminescence, are also fluorescent. This fluorescence has been documented in several genera within the clade but is still an often overlooked aspect of firefly physiology in the common understanding of the species. To this end, the purpose of this study was to document and describe the fluorescence in nine species of North American fireflies, across three genera. Each species was photographed and a description of the fluorescent pattern was provided, as well as measurements of the specific spectral sensitivity of the fluorescent excitation and emission wavelengths. These data are intended to provide an identification guide of sorts to different firefly fluorescence, as well as documenting definitively its presence in several firefly genera.

The Complete Mitochondrial Genome of the American Palm Cixiid, Haplaxius crudus (Hemiptera: Cixiidae)

Haplaxius crudus Van Duzee is a pest of various economically important palms due to its ability to transmit lethal yellowing, a fatal phytoplasma infection. It is also the putative vector of lethal bronzing in Florida, another lethal phytoplasma disease causing significant economic losses. To date, no mitochondrial genomes for species in the family Cixiidae are sequenced. In this study, the complete mitochondrial genome of H. crudus was sequenced, assembled, and annotated from PacBio Sequel II long sequencing reads using the University of Florida’s HiPerGator. The mitogenome of H. crudus is 15,848 bp long and encodes 37 mitochondrial genes (including 13 protein-coding genes (PCGs), 22 tRNAs, and 2 rRNAs) in addition to a putative noncoding internal control region. The nucleotide composition of H. crudus is asymmetric with a bias toward A/T (44.8 %A, 13.4 %C, 8.5 %G, and 33.3 %T). Protein-coding genes (PCGs) possess the standard invertebrate mitochondrial start codons with few exceptions while the gene content and order of the H. crudus mitogenome is highly similar to most completely sequenced insect mitochondrial genomes. Phylogenetic analysis based on the entire mitogenome shows H. crudus resolving closely to Delphacidae, the accepted sister taxon of Cixiidae. These data provide a useful resource for developing novel primer sets that could aid in either phylogenetic studies or population genetic studies. As more full mitogenomes become available in the future for other planthopper species, more robust phylogenies can be constructed, giving more accurate perspectives on the evolutionary relationships within this fascinating and economically important group of insects.

Diversity and Trophic Relationships of Functional Groups of Bumblebees (Hymenoptera: Apidae, Bombus Latreille, 1802) in Urban Habitats

Species composition, distribution, and trophic relationships of bumblebees are studied in six types of urban habitat: urban parks, botanical gardens, least-disturbed areas within the city, residential areas, and roadsides. Twenty bumblebee species are recorded in the present study. The species composition of bumblebees has changed from 1933 to 2017. Rare species have disappeared from the city—Bombus fragrans, B. cullumanus, and B. jonellus. The core of urban bumblebee communities consists of ecologically plastic species, most of which belong to the functional morphoecological “short-tongued” group (83%). The more specialized “medium-tongued” and “long-tongued” species are less diverse. Their populations make up 14% and 3% of the total bumblebee population. Five most common species, B. lucorum, B. terrestris, B. lapidarius, B. pascuorum, and B. hypnorum, are found at locations of the most noted categories of habitats. One of the main factors affecting the diversity of morphoecological groups of bumblebees in urban conditions is the state of floral resources. The bumblebees are observed feeding on more than 60 plant species of the families Asteraceae, Fabaceae, Lamiaceae, Rosaceae, and Salicaceae in urban environment; however, the insects favored plants of 30 species. The ornamental, ruderal, and some invasive species of plants are significant in bumblebees’ feeding in urban conditions. The resources for bumblebee feeding and sustainable density of nesting sites are rich in quality and quantity only at a few of model urban sites. At these territories, the highest species diversity of bumblebee is recorded, including rare, protected, and vulnerable species. The ecological potential of other studied urban sites is enough to sustain the most ecologically plastic bumblebee species.

Antioviposition and Reduction of Callosobruchus chinensis Pic. 1902 (Coleoptera: Bruchidae) Emergence on Phaseolus vulgaris by Dioscorea sansibarensis Powder and Its Chemical Composition

Callosobruchus chinensis causes damage to the Phaseolus vulgaris seeds. Traditionally, Dioscorea sansibarensis serves as a medicinal plant. Naturally, D. sansibarensis has toxins that protect against herbivores and the surrounding invasive plants in its natural habitat. Phytochemical analysis by thin-layer chromatography (TLC) and laboratory experiments was carried out to determine the activity of D. sansibarensis leaves, bulbils, and yams powders on antioviposition and inhibition of the F1 emergence of C. chinensis. Bioassay data were subjected to nonparametric (Kolmogorov–Smirnov) statistical analysis and a generalized linear model at P ≤ 0.05 . Statistically, the powders had an antioviposition activity of 34.3% (R2 = 0.343). A recommendable activity on antioviposition was displayed by the yams powder; treatment by 0.8 g of yams powder had a Wald Chi-Square value of 1.291, P = 0.26 . Inhibition of F1 emergence was significantly attained by the yams powder; the treatment by 0.6 g of yams powder had a Wald Chi-Square value of 7.72, P = 0.01 . Statistically, the bulbils powder displayed low antioviposition and inhibition of F1 emergence. Observations on the TLC exposed compounds with similar Rf values; saponin with an Rf value of 0.72 was portrayed in the leaves, bulbils, and yams. A terpenoid and a flavonoid with Rf values of 0.37 and 0.71, respectively, were observed in bulbils and yams but absent in leaves. A terpenoid with an Rf value of 0.49 was visualized in leaves and bulbils but not in the yams powder. The study concluded that the D. sansibarensis yams and leaves powders are viable for application by the farmers in the protection of stored legumes against attack by C. chinensis. However, there may be other diverse interests in other storage insects and other methods of phytochemical analysis that have not been investigated.