Identification of stingless bees (Hymenoptera: Apidae) in Kenya using Morphometrics and DNA barcoding

Stingless bees are important pollinators of wild plants and crops. The identity of stingless bee species in Africa has not been fully documented. The present study explored the utility of morphometrics and DNA barcoding for identification of African stingless bee populations, and to further employ these tools to identify potential cryptic variation within species. Stingless bee samples were collected from three ecological zones, namely Kakamega Forest, Mwingi and Arabuko-Sokoke Forest, which are geographically distant and cover high, medium and low altitudes, respectively. Forewing and hind leg morphometric characters were measured to determine the extent of morphological variation between the populations. DNA barcodes were generated from the mitochondrial cytochrome c-oxidase I (COI) gene. Principal Component Analysis (PCA) on the morphometric measurements separated the bee samples into three clusters: (1) Meliponula bocandei; (2) Meliponula lendliana + Plebeina hildebrandti; (3) Dactylurina schmidti + Meliponula ferruginea black + Meliponula ferruginea reddish brown, but Canonical Variate Analysis (CVA) separated all the species except the two morphospecies (M. ferruginea reddish brown and black). The analysis of the COI sequences showed that DNA barcoding can be used to identify all the species studied and revealed remarkable genetic distance (7.3%) between the two M. ferruginea morphs. This is the first genetic evidence that M. ferruginea black and M. ferruginea reddish brown are separate species

Black soldier fly-composted organic fertilizer enhances growth, yield, and nutrient quality of three key vegetable crops in Sub-Saharan Africa

Norwegian Agency for Development CooperationNetherlands Organization for Scientific ResearchWOTRO Science for Global Development (NWO-WOTRO)Australian Centre for International Agricultural Research (ACIAR)Rockefeller Foundatio

Nest architecture as a tool for species discrimination of Hypotrigona species (Hymenoptera: Apidae: Meliponini)

Hypotrigona species are difficult to identify morphologically. Here, we show that nest sites and nest architecture can be used to discriminate three Hypotrigona species found in Kenya. Hypotrigona gribodoi, H. araujoi and H. ruspolii colonies from Kakamega forest and H. gribodoi from Mwingi, were collected and placed in a meliponiary at the International Centre of Insect Physiology and Ecology (ICIPE). The following parameters were recorded: nest sites, internal nest entrances, external nest entrance colour and size, sizes (in terms of volume) of brood cells, honey and pollen pots, arrangement of brood cells and presence or absence of involucrum (cerumen covering brood). It was found that nest sites are specific to species. Hypotrigona gribodoi nests mostly in crevices inmudwalls whileH. ruspolii and H. araujoi nest in cavities in specific tree species, mainly in indigenous forests. The colour of external nest entrances varies between the species. H. araujoi’s is yellowish brown, H. gribodoi’s is white or cream while that ofH. ruspolii is dark brown. There is an internal nest entrance inH. gribodoi, which is absent in the other two Hypotrigona species. Brood cells are clustered in H. gribodoi and H. ruspolii whereas H. araujo’s formvertical semi comb-like layers. The area of the apical opening of the entrance tube and volumes of brood cells, honey and pollen pots differ significantly between the three Hypotrigona species. Therefore, nest sites and nest architecture can be used to discriminate three Hypotrigona species. Furthermore, the study indicates that conservation of indigenous forests, the main habitat for H. araujoi and H. ruspolii is important for their conservation.https://journals.co.za/content/journal/entohj2020Zoology and Entomolog

Nest Architecture as a Tool for Species Discrimination of Hypotrigona Species (Hymenoptera: Apidae: Meliponini)

Hypotrigona species are difficult to identify morphologically. Here, we show that nest sites and nest architecture can be used to discriminate three Hypotrigona species found in Kenya. Hypotrigona gribodoi, H. araujoi and H. ruspolii colonies from Kakamega forest and H. gribodoi from Mwingi, were collected and placed in a meliponiary at the International Centre of Insect Physiology and Ecology (ICIPE). The following parameters were recorded: nest sites, internal nest entrances, external nest entrance colour and size, sizes (in terms of volume) of brood cells, honey and pollen pots, arrangement of brood cells and presence or absence of involucrum (cerumen covering brood). It was found that nest sites are specific to species. Hypotrigona gribodoi nests mostly in crevices inmudwalls whileH. ruspolii and H. araujoi nest in cavities in specific tree species, mainly in indigenous forests. The colour of external nest entrances varies between the species. H. araujoi’s is yellowish brown, H. gribodoi’s is white or cream while that ofH. ruspolii is dark brown. There is an internal nest entrance inH. gribodoi, which is absent in the other two Hypotrigona species. Brood cells are clustered in H. gribodoi and H. ruspolii whereas H. araujo’s formvertical semi comb-like layers. The area of the apical opening of the entrance tube and volumes of brood cells, honey and pollen pots differ significantly between the three Hypotrigona species. Therefore, nest sites and nest architecture can be used to discriminate three Hypotrigona species. Furthermore, the study indicates that conservation of indigenous forests, the main habitat for H. araujoi and H. ruspolii is important for their conservation.https://journals.co.za/content/journal/entohj2020Zoology and Entomolog

Body size as a proxy of probing time and visitation rates on cucumber by two African stingless bees increase fruit quality and seed quantity

Pollinators are of essential importance for sustainable agriculture. However, pollination efficiency depends on interacting factors such as pollinator behaviour and morphology. We compared the effect of probing time length and visit frequency of two distinct body size African stingless bee species (Meliponula bocandei, Dactylurina schmidti) as alternative pollinators to Apis mellifera scutellata on greenhouse cultivated cucumber. We found differences in morphometric characteristics, between a set of 9 body parameters. Bee body size was the morphological feature that varied the most among bee species. On average, body size was largest in honeybees, followed by M. bocandei, and finally D. schmidti, which was the smallest. Glossa length was different between the bee species: A. mellifera scutellata (2.86 ± 0.026 mm), M. bocandei (2.20 ± 0.031 mm), D. schmidti (0.72 ± 0.025 mm). Such differences among bee species in body parameters correspondingly affected nectar probing times during a single flower visit, which were different for the bee species. D. schmidti (3.34 ± 0.56 s) had the longest probing time, while M. bocandei (2.57 s) had the shortest. Fruit quality was strongly positively influenced by the visit duration during a single visit on female flowers. The slope of fruit quality produced was higher in flowers pollinated by M. bocandei. During a single flower visit, heavier and bigger fruits were obtained in the gold standard hand cross pollination and flowers pollinated by M. bocandei. The bee species and the number of visits significantly impacted fruit weight, fruit volume and number of seeds. Subsequent visit performed by M. bocandei positively impacted fruit quality. Three visits on a flower were enough to ensure the production of high-quality fruits. Fruit sweetness depended on the number of visits received by the flower, but not on the bee species that performed the visit. Altogether, our results indicate that the stingless bees M. bocandei is more an efficient pollinator of cucumber than A. m. scutellata and D. schmidti and can be recommended for use under greenhouse cultivation

Resolviendo la ambigüedad taxonómica y la especiación críptica de las especies de Hypotrigona a través de la morfometría y el código de barras de ADN

Stingless bees are important pollinators of cultivated and wild plants, contributing significantly to biodiversity and food security. Conserving pollinator plant interactions is essential to secure these ecosystems services. The use of morphological features in the identification of stingless bees in the genus Hypotrigona is extremely difficult, due to many similarities among species resulting in taxonomic ambiguity. Here, we apply both traditional morphometrics and DNA barcoding as complementary tools for the identification of three Hypotrigona species from Kenya: Hypotrigona gribodoi, H. ruspolii and H. araujoi. Our results show that morphometrics separates H. gribodoi and H. ruspolii from H. araujoi; however there is an overlap between H. gribodoi and H. ruspolii. On the other hand, DNA barcoding separates the three species. There was lower genetic distance between H. araujoi and H. gribodoi from Kakamega (1.4%) than between H. gribodoi collected from Kakamega and H. gribodoi from Mwingi (4.3%). The high genetic distance or intraspecific distance within H. gribodoi strongly suggests cryptic speciation within this species, and that the H. gribodoi collected from Mwingi is a putative new species. Thus the use of morphometrics and molecular taxonomic approaches (DNA barcoding) provide a convenient, robust and reliable way to identify Hypotrigona species. It also indicates the need for a thorough revision of H. gribodoi species.Las abejas sin aguijón son importantes polinizadores de plantas cultivadas y silvestres, contribuyendo significativamente a la biodiversidad y la seguridad alimentaria. La conservación de las interacciones entre plantas polinizadoras es esencial para asegurar estos servicios de los ecosistemas. El uso de las características morfológicas en la identificación de las abejas sin aguijón en el género Hypotrigona es extremadamente difícil, debido a múltiples similitudes entre especies que dan lugar a ambigüedades taxonómicas. Aquí aplicamos tanto la morfometría tradicional como el código de barras de ADN como herramientas complementarias para la identificación de tres especies de Hypotrigona de Kenia: Hypotrigona gribodoi, H. ruspolii y H. araujoi. Nuestros resultados muestran que la morfometría separa a H. gribodoi y H. ruspolii de H. araujoi; sin embargo, existe un solapamiento entre H. gribodoi y H. ruspolii. Por otra parte, el código de barras de ADN separa las tres especies. Hubo una menor distancia genética entre H. araujoi y H. gribodoi de Kakamega (1,4%) que entre H. gribodoi de Kakamega y H. gribodoi de Mwingi (4.3%). La mayor distancia genética o distancia intraespecífica dentro de H. gribodoi sugiere fuertemente la especiación críptica dentro de esta especie, y que H. gribodoi recogida de Mwingi es una nueva especie putativa. Por lo tanto, el uso de la morfometría y los enfoques taxonómicos moleculares (código de barras de ADN) proporcionan una manera conveniente, robusta y confiable de identificar especies de Hypotrigona. También indica la necesidad de realizar una revisión exhaustiva de las especies de H. gribodoi.http://www.tandfonline.com/loi/tjar202019-02-15hj2018Zoology and Entomolog

Seasonal and elevational changes of plant‐pollinator interaction networks in East African mountains

Abstract Across an elevation gradient, several biotic and abiotic factors influence community assemblages of interacting species leading to a shift in species distribution, functioning, and ultimately topologies of species interaction networks. However, empirical studies of climate‐driven seasonal and elevational changes in plant‐pollinator networks are rare, particularly in tropical ecosystems. Eastern Afromontane Biodiversity Hotspots in Kenya, East Africa. We recorded plant‐bee interactions at 50 study sites between 515 and 2600 m asl for a full year, following all four major seasons in this region. We analysed elevational and seasonal network patterns using generalised additive models (GAMs) and quantified the influence of climate, floral resource availability, and bee diversity on network structures using a multimodel inference framework. We recorded 16,741 interactions among 186 bee and 314 plant species of which a majority involved interactions with honeybees. We found that nestedness and bee species specialisation of plant‐bee interaction networks increased with elevation and that the relationships were consistent in the cold‐dry and warm‐wet seasons respectively. Link rewiring increased in the warm‐wet season with elevation but remained indifferent in the cold‐dry seasons. Conversely, network modularity and plant species were more specialised at lower elevations during both the cold‐dry and warm‐wet seasons, with higher values observed during the warm‐wet seasons. We found flower and bee species diversity and abundance rather than direct effects of climate variables to best predict modularity, specialisation, and link rewiring in plant‐bee‐interaction networks. This study highlights changes in network architectures with elevation suggesting a potential sensitivity of plant‐bee interactions with climate warming and changes in rainfall patterns along the elevation gradients of the Eastern Afromontane Biodiversity Hotspot

Black Soldier Fly-Composted Organic Fertilizer Enhances Growth, Yield, and Nutrient Quality of Three Key Vegetable Crops in Sub-Saharan Africa

Worldwide, French beans (Phaseolus vulgaris L.), tomato (Solanum lycopersicum L.), and kales (Brassica oleracea L. var. acephala) are considered economically important food crops. There is a rapid decline in their yield due to severe soil degradation. Thus, high commercial fertilizer inputs are crucial, though they remain expensive and inaccessible to resource poor farmers. We investigated the comparative performance of composted black soldier fly frass fertilizer (BSFFF), conventionally composted brewer's spent grain (BSG), commercial organic fertilizer (Evergrow), and mineral [nitrogen, phosphorus, and potassium (NPK)] fertilizer on growth, yield, N use efficiency, and nutritional quality (crude protein, crude fiber, crude fats, ash, and carbohydrate concentrations) of tomatoes, kales, and French beans under greenhouse and open-field conditions for two seasons. The fertilizers were applied at rates equivalent to 371 kg of N ha−1. For each crop, the plots were treated with sole rates of BSFFF, BSG, Evergrow, and NPK to supply 100% of the N required. Additional treatments included a combination of BSFFF and NPK, and BSG and NPK so that each fertilizer supplies 50% of the N required. The control treatment consisted of unfertilized soil. Results show that vegetable yields achieved using a combination of BSFFF and NPK were 4.5, 2.4, and 5.4-folds higher than the yield from the control treatment for tomatoes, kales, and French beans, respectively. The combined application of BSFFF and NPK produced 22–135%, 20–27%, and 38–50% higher yields than sole NPK for tomatoes, kales, and French beans, respectively, under both greenhouse and open-field conditions. The highest agronomic N use efficiency was achieved in sole BSFFF-treated plots compared to sole BSG and Evergrow. The N taken up by the vegetables was significantly higher when BSFFF and NPK were integrated. Vegetables grown using a combination of BSFFF and NPK had the highest crude protein and ash concentrations. Our findings demonstrate that the integration of BSFFF and NPK in vegetable cropping systems at the recommended rate of 1.24 t ha−1 BSFFF and 322 kg ha−1 NPK would improve soil health, boost yield, and nutritional quality of vegetable crops

Resolving taxonomic ambiguity and cryptic speciation of <i>Hypotrigona</i> species through morphometrics and DNA barcoding

<p>Stingless bees are important pollinators of cultivated and wild plants, contributing significantly to biodiversity and food security. Conserving pollinator plant interactions is essential to secure these ecosystems services. The use of morphological features in the identification of stingless bees in the genus <i>Hypotrigona</i> is extremely difficult, due to many similarities among species resulting in taxonomic ambiguity. Here, we apply both traditional morphometrics and DNA barcoding as complementary tools for the identification of three <i>Hypotrigona</i> species from Kenya: <i>Hypotrigona gribodoi, H. ruspolii</i> and <i>H. araujoi.</i> Our results show that morphometrics separates <i>H. gribodoi</i> and <i>H. ruspolii</i> from <i>H. araujoi</i>; however there is an overlap between <i>H. gribodoi</i> and <i>H. ruspolii</i>. On the other hand, DNA barcoding separates the three species. There was lower genetic distance between <i>H. araujoi</i> and <i>H. gribodoi</i> from Kakamega (1.4%) than between <i>H. gribodoi</i> collected from Kakamega and <i>H. gribodoi</i> from Mwingi (4.3%). The high genetic distance or intraspecific distance within <i>H. gribodoi</i> strongly suggests cryptic speciation within this species, and that the <i>H. gribodoi</i> collected from Mwingi is a putative new species<i>.</i> Thus the use of morphometrics and molecular taxonomic approaches (DNA barcoding) provide a convenient, robust and reliable way to identify <i>Hypotrigona</i> species. It also indicates the need for a thorough revision of <i>H. gribodoi</i> species.</p