Differences in the biochemical content and radical scavenging activity of propolis from different parts of a Meliponula ferruginea hive.

Research on stingless bee products has increased in recent years, and of particular interest is propolis because of its biological activities such as antioxidant and antimicrobial. However, there is paucity of information regarding intra-hive variations in the biochemical composition and biofunctional properties of this propolis. In this study, we investigated the phytochemicals and radical scavenging activity (RSA) of Meliponula ferruginea propolis from 10 wooden hives (n = 49). The samples were collected from five different locations comprising the entrance, involucrum, pillars, pots and sealant. Principal component analysis showed that there is an intra-hive variation in phytochemical content and RSA. Phenolic content constituted the highest phytochemical content in all the locations. The sealant and entrance had the highest amounts of phytochemicals compared to the involucrum, pillars and pots. Further analysis of propolis extracts by gas chromatography-mass spectrometry revealed occurrence of different compounds such as monoterpenoids, hydrocarbons, triterpenoids and alkaloids. Hydrocarbons were common in all parts while monoterpenes and triterpenes were present in the entrance. The findings of our study indicates that there is an intra-hive variation in propolis of M. ferruginea and hence this information will provide further insight into better understanding of stingless bee propolis.

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

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.

Protein Content and Amino Acid Profiles of Selected Edible Insect Species from the Democratic Republic of Congo Relevant for Transboundary Trade across Africa.

This study analyzed the protein content of ten edible insect species (using the Dumas method), then focused on the amino acid (AA) profiles of the six major commercially relevant species using HPLC (high-pressure (or performance) liquid chromatography). The protein contents varied significantly from 46.1% to 52.9% (dry matter); the Orthoptera representative yielding both the highest protein content and the highest values in three essential amino acids (EAAs). Regarding Lepidoptera species, the protein content of Saturniidae varied more than for Notodontidae. Imbrasia ertli gave the best example of a species that could be suggested for dietary supplementation of cereal-based diets, as the sample contained the highest values in five EAAs and for the EAA index. Furthermore, first-limiting AAs in the selected insects have also been pointed out (based on a species-specific AA score), supporting that the real benefit from eating insects is correlated to a varied diet. Additionally, preliminary insights into AA distribution patterns according to taxa provided three clusters based on protein quality and should be completed further to help tailor prescriptions of dietary diets. Since the AA composition of the selected insects was close to the FAO/WHO EAA requirement pattern for preschool children and met the requirements of 40% EAAs with high ratio EAAs/NEAAs, the current study endorses reports of edible insects as nutrient-rich and sustainable protein sources.

Susceptibility of the Western Honey Bee Apis mellifera and the African Stingless Bee Meliponula ferruginea (Hymenoptera: Apidae) to the Entomopathogenic Fungi Metarhizium anisopliae and Beauveria bassiana.

This study assessed the nontarget effect of entomopathogenic fungi on the Western honey bee Apis mellifera L. and the African stingless bee Meliponula ferruginea Cockrell (Hymenoptera: Apidae). Pathogenicity of five Metarhizium anisopliae (ICIPE 7, ICIPE 20, ICIPE 62, ICIPE 69, and ICIPE 78) (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae) and one of Beauveria bassiana (ICIPE 284) (Balsamo) Vuillemin (Hypocreales: Cordicipitaceae) isolates were evaluated on bees at 108 conidia/ml. Conidial acquisition was evaluated immediately after exposure. Apis mellifera acquired more conidia (2.8 × 104-1.3 × 105 conidia per bee) compared to M. ferruginea (1.1 × 104-2.3 × 104 conidia per bee). In the bioassay with A. mellifera, ICIPE 7, ICIPE 20, and ICIPE 69 moderately reduced the survival by 16.9, 17.4, 15.3%, with lethal times LT10 = 7.4, 7.6, 8.1 d and LT25 = 8.7, 10.0, 9.9 d, respectively. The three isolates caused A. mellifera mycosis of 11.6-18.5%. None of the isolates had a significant effect on M. ferruginea. The tested isolates are nontoxic to bees according to the International Organization of Biological Control (IOBC) classification. However, the effect of ICIPE 7, ICIPE 20, and ICIPE 69 merits further studies on bee colonies, especially those of A. mellifera, under field conditions.