Developmental changes in larvae of the oriental latrine fly, Chrysomya megacephala, exposed to deltamethrin.

The Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) has a worldwide distribution and is considered of medical and veterinary importance. Its synanthropic behavior combined with the visitation of decaying organic matter allows it to mechanically transmit pathogens to human and animals. Pyrethroids are widely used pesticides, effective in low doses against a broad spectrum of insects. Our objective was to evaluate the action of K-Othrine® on the post-embryonic development of C. megacephala. First instar larvae were exposed to different concentrations of K-Othrine® (3.75 × 10-5 g a.i/mL (low), 7.5 × 10-5 g a.i/mL (intermediate low), 1.125 × 10-4 g a.i/mL (intermediate), 1.5 × 10-4 g a.i/mL (intermediate high), and 2.5 × 10-4 g a.i/mL (high)) mixed into artificial diets and a control with no pesticide. We measured weight, time of development, sex ratio, larval and pupal mortality, and esterase patterns. The mean weight values at intermediate low and intermediate concentrations were significantly lower compared with the control; additionally, the development time was delayed compared with the control. The larval and pupal mortality differed among the treatments. The larvae had six esterase regions, which altered its relative activity at 48 h and 72 h after insecticide ingestion. Further studies must investigate the effects of different insecticides on the post-embryonic development of C. megacephala.

Toxicity and effects of the neonicotinoid thiamethoxam on Scaptotrigona bipunctata lepeletier, 1836 (Hymenoptera: Apidae).

The neonicotinoid thiamethoxam is widely used in different agricultural crops, and it has a spectrum of action against insects, affecting both pests and pollinators, such as bees. In this study, the effects of exposure to sublethal concentrations of thiamethoxam on stingless bees Scaptotrigona bipunctata were evaluated. Foragers bees were exposed to the insecticide and subjected to genetic biochemical, histochemical, and morphological analyses after 24, 48, and 72 h of ingestion. Analysis of isoenzyme esterases revealed significant alterations in the relative activity of EST-4, a type II cholinesterase. Evaluation of the S. bipunctata brain revealed changes in the state of chromatin condensation according to the exposure time and concentration of neonicotinoid compared with the control. Morphological changes were observed in the midgut of this species at all concentrations and exposure times, which may interfere with various physiological processes of these insects. We can conclude that, although thiamethoxam at the concentrations evaluated did not cause high mortality, it induced concentration-dependent changes in bees by activating enzymes related with the protection for xenobiotic, internal morphology and probably these changes may lead to alterations in the activity of bees.

Expression of MRJP3 and HSP70 mRNA Levels in Apis mellifera L. Workers after Dietary Supplementation with Proteins, Prebiotics, and Probiotics.

Royal jelly is an essential substance for the development of bees from larval to adult stages. Studies have identified a group of key proteins in royal jelly, denominated major royal jelly proteins (MRJPs). The group currently consists of nine proteins (MRJP1-MRJP9), with MRJP1 being the most abundant and MRJP3 being used as a microsatellite marker for the selection of queens with a greater production of royal jelly. The diet of bees is mostly composed of proteins, and supplementing this intake to encourage a higher production of their primary product is important for producers. It is estimated that, by adding probiotic and prebiotic organisms to their diets, the benefits to bees will be even greater, both for their immune systems and primary responses to stress. Circumstances that are adverse compared to those of the natural habitat of bees eventually substantially interfere with bee behavior. Stress situations are modulated by proteins termed heat shock proteins (HSPs). Among these, HSP70 has been shown to exhibit abundance changes whenever bees experience unusual situations of stress. Thus, we sought to supplement A. mellifera bee colony diets with proteins and prebiotic and probiotic components, and to evaluate the expression levels of MRJP3 and HSP70 mRNAs using qRT-PCR. The results revealed that differences in the expression of MRJP3 can be attributed to the different types of feed offered. Significant differences were evident when comparing the expression levels of MRJP3 and HSP70, suggesting that protein supplementation with pre/probiotics promotes positive results in royal jelly synthesis carried out by honey bee nurses.

Imidacloprid Induces Histopathological Damage in the Midgut, Ovary, and Spermathecal Stored Spermatozoa of Queens After Chronic Colony Exposure.

Bee colony health is declining as a result of several factors, including exposure to pesticides. The development and strength of honey bee colonies depend on the reproductive success of queen bees. Because flowers are sources of food for bees, foragers can accidentally collect and carry contaminated pollen and nectar to their hives; and this may compromise the longevity and the life span of individuals. Thus, the present study aimed to observe the action of imidacloprid in the midgut and ovaries of Apis mellifera queens, as well as the effects on sperm stored in their spermatheca. To this end, the apiary was divided into three experimental groups: control, commercial imidacloprid, and active ingredient imidacloprid. For toxicity assays, a sucrose solution containing 1 µg/L of imidacloprid was offered to the colonies for 42 days. A control group received only food in the same period. In both treatments with imidacloprid, the midgut of queens showed modifications in the external musculature and cellular alterations. Such changes could lead to the nonrecovery of the epithelium and subsequently malabsorption of nutrients. Moreover, the digestive cells of queen bees exposed to the commercial imidacloprid presented pyknotic nuclei, suggesting a cell death process. The main alterations observed in the ovaries of these reproductive bees treated with commercial imidacloprid were degeneration and resorption of the ovariole content, which probably affected their fertilization and colony development. There were no significant changes in the spermatozoa morphology for both treatments with imidacloprid, but this insecticide may interfere with the development and reproductive success of A. mellifera colonies because it affects the morphology and function of essential organs for the survival of queens. Environ Toxicol Chem 2022;41:1637-1648. SETAC.

Bioprospection of immature salivary glands of Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae).

Larval therapy (LT) comprises the application of sterile Calliphoridae larvae for wound debridement, disinfection, and healing in humans and animals. Larval digestion plays a key role in LT, where the salivary glands and gut produce and secrete proteolytic and antimicrobial substances. The objective of this work was to bioprospect the salivary glands of Chrysomya megacephala (Fabricius, 1794) larvae, using ultrastructural, morphological, and histological observations, and the total protein electrophoretic profile. The salivary glands present a deferent duct, originating from the buccal cavity, which bifurcates into efferent ducts that insert through a slight dilatation to a pair of tubular-shaped tissues, united in the region of fat cells. Histologically, the secretion had protein characteristics. Cell cytoplasm presented numerous free ribosomes, autophagic vacuoles, spherical and elongated mitochondria, atypical Golgi complexes, and dilated rough endoplasmic reticulum. In the apical cytoplasm, secretory granules and microvilli secretions demonstrated intense protein synthesis, basal cytoplasm with trachea insertions, and numerous mitochondria. The present work described the ultrastructure and morphology of C. megacephala third instar salivary glands, confirming intense protein synthesis and the molecular weight of soluble proteins.

Multiple resistance to pirimiphos-methyl and bifenthrin in Tribolium castaneum involves the activity of lipases, esterases, and laccase2.

Several recent studies have elucidated the molecular mechanisms that confer insecticide resistance on insect pests. However, little is known about multiple resistance in red flour beetle (Tribolium castaneum) at molecular level. The multiple resistance is characterized as resistance to different classes of insecticides that have different target sites, and is mediated by several enzymatic systems. In this study, we investigated the biochemical and molecular mechanisms involved in multiple resistance of T. castaneum to bifenthrin (pyrethroid [Pyr]) and pirimiphos-methyl (organophosphate [Org]). We used artificial selection, biochemical and in silico approaches including structural computational biology. After five generations of artificial selection in the presence of bifenthrin (F5Pyr) or pirimiphos-methyl (F5Org), we found high levels of multiple resistance. The hierarchical enzymatic cluster revealed a pool of esterases (E), lipases (LIPs) and laccase2 (LAC2) potentially contributing to the resistance in different ways throughout development, after one or more generations in the presence of insecticides. The enzyme-insecticide interaction network indicated that E2, E3, LIP3, and LAC2 are enzymes potentially required for multiple resistance phenotype. Kinetic analysis of esterases from F5Pyr and F5Org showed that pirimiphos-methyl and specially bifenthrin promote enzyme inhibition, indicating that esterases mediate resistance by sequestering bifenthrin and pirimiphos-methyl. Our computational data were in accordance with kinetic results, indicating that bifenthrin has higher affinity at the active site of esterase than pirimiphos-methyl. We also report the capability of these insecticides to modify the development in T. castaneum. Our study provide insights into the biochemical mechanisms employed by T. castaneum to acquire multiple resistance.

Analysis of a dose-response assay in Scaptotrigona bipunctatabees, Lepeletier, 1836 (Hymenoptera: Apidae) using the logistic regression model under the Bayesian approach

This paper shows the results of a dose-response study in Scaptotrigona bipunctatabees, Lepeletier, 1836 (Hymenoptera: Apidae) exposed to the insecticide Fastac Duo. The aim was to evaluate the lethal concentration that causes the death of 50% of bees (LC50) and investigate the odd of mortality after exposure to different concentrations, using the logistic regression model under the Bayesian approach. In this approach, it is possible to incorporate a prior information and gives more accurate inferential results. Three independent dose-response experiments were analyzed, dissimilar in their lead time according to guidelines from the Organisation for Economic Co-operation and Development (OECD), in which each assay contained four replicates at the concentration levels investigated, including control. Observing exposure to the agrochemical, it was identified that the higher the concentration, the greater the odd of mortality. Regarding the estimated lethal concentrations for each experiment, the following values were found, 0.03 g a.i. L-1, for 24hours, 0.04 g a.i. L-1, for 48hoursand 0.06 g a.i. L-1for 72hours, showing that in experiments with longer exposure times there was an increase in LC50. Concluding, the study showed an alternative approach to classical methods for dose-response studies in Scaptotrigona bipunctatabees exposed to the insecticide Fastac Duo.

Morpho-functional characterization and esterase patterns of the midgut of Tribolium castaneum Herbst, 1797 (Coleoptera: Tenebrionidae) parasitized by Gregarina cuneata (Apicomplexa: Eugregarinidae).

Tribolium castaneum (Coleoptera: Tenebrionidae) is a common pest of stored grains and byproducts and is normally infected by Gregarina cuneata (Apicomplexa: Eugregarinidae). The life cycle of this parasite includes the sporozoite, trophozoite, gamont, gametocyte, and oocyst stages, which occur between the epithelium and lumen of the host's midgut. This study aims to describe the morphofunctional alterations in the midgut and determine the esterase patterns in T. castaneum when parasitized by gregarines. To achieve this purpose, midguts of adult insects were isolated, processed, and analysed using light and electron microscopy. We determined total protein content, amylase activity, and the expression and related activities of the esterases by using polyacrylamide gel electrophoresis (PAGE). The midgut of T. castaneum is formed by digestive, regenerative, and endocrine cells. The effects of parasitism on the digestive cells are severe, because the gregarines remain attached to these cells to absorb all the nutrients they need throughout their development. In these cells, the most common alterations observed include expansion and fragmentation of the rough endoplasmic reticulum, development of the smooth endoplasmic reticulum, changes in mitochondrial cristae, cytoplasmic vacuolization, formation of myelin structures, spherites, large intercellular spaces, autophagic vesicles, expansion of the basal labyrinth, and cytoplasmic protrusions. Deposits of glycogen granules were also observed. Amylase activity was reduced in parasitized insects. Regenerative cells were found in disorganized crypts and did not differentiate into new cells, thus, compromising the restoration of the damaged epithelium. Though few morphological alterations were observed in the endocrine cells, results suggest that the synthesis and/or release of hormones might be impaired. Nine esterases (EST-1 to 9) were identified in the midgut of T. castaneum and were expressed in varying levels in response to parasitism. Two additional isoforms of esterases were exclusively identified in the parasitized insects. The results of this study suggest that gregarines alter the morphology and physiology of the midgut. The changes may result in nutritional depletion and the impairment of other physiological processes, such as reproduction and development of the host. Thus, further studies are needed to uncover the possibility of utilizing gregarines as biological controllers of the insect pest population.

Effects of biopesticides in Tetragonisca angustula latreille (Hymenoptera: Meliponinae) pollinators / Efeitos de biopesticidas em polinizadores Tetragonisca angustula latreille (Hymenoptera: Meliponinae) / Efectos de los bioplaguicidas sobre los polinizadores Tetragonisca angustula latreille (Hymenoptera: Meliponinae)

Stingless bees Tetragonisca angustula (Latreille) (Hymenoptera: Meliponinae) are pollinators of native and cultivated plants and are therefore in contact with areas contaminated by pesticides. These native bees were evaluated for changes in gene expression of esterase isoenzymes (EST) and peptides after contamination by contact with growth regulators from insecticides Gallaxy® EC 100, Natuneem and Azamax after 48, 120, 168 hours, 30 and 60 days. EST-4 presented an increase in relative activity after contamination with Gallaxy® EC 100 at 6.2 × 10-2 g a.i./mL; Natuneem at 7.5 × 10-5 g a.i./mL; and Azamax at 1.2 × 10-3 g a.i/mL after 60 days, 48 h, and 60 days, respectively. Inhibition of the relative activity of EST-4 was detected after contamination by Natuneem at 1.5 × 10-5 g a.i./mL and Azamax at 1.2 × 10-3 g a.i./mL after 48 h and 30 days, respectively. The insecticide growth regulators promoted changes in protein synthesis of T. angustula adult workers resulting in an increase or decrease in the relative intensity of bands, and the appearance of new peptides when compared with controls. Changes in protein synthesis have been identified mainly after long period of contamination, 120 and 168 h with the IGRs Gallaxy® EC 100 (at 0.78 and 1.25 g a.i./mL), Azamax (at 1.2 × 10-3 and 6 × 10-3 g a.i./mL), and Natuneem (at 7.5 × 10-5 and 3 × 10-3 g a.i./mL), and at 60 days with Natuneem (at 1.5 × 10-5 g a.i./mL).(AU)

Abelhas sem ferrão Tetragonisca angustula (Latreille) (Hymenoptera: Meliponinae) são polinizadores de plantas nativas e cultivadas e, portanto, estão em contato com áreas contaminadas por biopesticidas. Essas abelhas nativas foram avaliadas quanto a alterações na expressão gênica de isoenzimas esterases (EST) e peptídeos após contaminação por contato com reguladores de crescimento de inseticidas Gallaxy® EC 100, Natuneem e Azamax após 48, 120, 168 horas, 30 e 60 dias. A EST-4 apresentou um aumento na atividade relativa após a contaminação com Gallaxy® 100 EC em 6,2 × 10-2 g i.a./mL, Natuneem em 7,5 × 10-5 g i.a./mL e Azamax em 1,2 × 10-3 g i.a./mL após 60 dias, 48 h e 60 dias, respectivamente. A inibição da atividade relativa de EST-4 foi detectada após contaminação pelo Natuneem a 1,5 × 10-5 g i.a./mL e Azamax a 1,2 × 10-3 g i.a./mL após 48 he 30 dias, respectivamente. Os reguladores de crescimento de inseticidas promoveram alterações na síntese protéica de trabalhadores adultos de T. angustula, resultando em um aumento ou diminuição da intensidade relativa das bandas e no aparecimento de novos peptídeos em comparação com os controles. Alterações na síntese de proteínas foram identificadas principalmente após um longo período de contaminação, 120 e 168 h com o IGRs Gallaxy® EC 100 (0,78 e 1,25 g i.a./mL), Azamax (1,2 × 10-3 e 6 × 10-3 g i.a./mL) e Natuneem (7,5 × 10-5 e 3 × 10-3 g i.a./mL) e 60 dias com Natuneem (1,5 × 10-5 g i.a./mL).(AU)

Las abejas sin aguijón Tetragonisca angustula (Latreille) (Hymenoptera: Meliponinae) son polinizadores de plantas nativas y cultivadas y, por lo tanto, están en contacto con áreas contaminadas por bioplaguicidas. Estas abejas nativas fueron evaluadas para detectar cambios en la expresión génica de isoenzimas esterasa (EST) y péptidos después de la contaminación por contacto con los reguladores del crecimiento insecticidas Gallaxy® EC 100, Natuneem y Azamax después de 48, 120, 168 horas, 30 y 60 días. EST-4 mostró un aumento en la actividad relativa después de la contaminación con Gallaxy® 100 EC a 6.2 × 10-2 g i.a./mL, Natuneem a 7.5 × 10-5 g i.a./mL y Azamax a 1.2 × 10-3 g i.a./mL después de 60 días, 48 hy 60 días, respectivamente. La inhibición de la actividad relativa de EST-4 se detectó después de la contaminación por Natuneem a 1.5 × 10-5 g i.a./mL y Azamax a 1.2 × 10-3 g i.a./mL después de 48 hy 30 días. respectivamente. Los insecticidas reguladores del crecimiento promovieron cambios en la síntesis de proteínas de trabajadores adultos de T. angustula, resultando en un aumento o disminución de la intensidad relativa de las bandas y en la aparición de nuevos péptidos en relación a los controles. Los cambios en la síntesis de proteínas se identificaron principalmente después de un largo período de contaminación, 120 y 168 h con IGRs Gallaxy® EC 100 (0.78 y 1.25 g i.a./mL), Azamax (1.2 × 10-3 y 6 × 10-3 g i.a./mL) y Natuneem (7.5 × 10-5 y 3 × 10-3 g i.a./mL) y 60 días con Natuneem (1.5 × 10-5 g i.a./mL).(AU)

Comparative electrophoretic profile of proteins and esterases in healthy silkworm larvae (Bombyx mori Lineu, 1758) and infected with nucleopolyhedrovirus / Perfil eletroforético comparativo de proteínas e esterases em lagartas de bicho da seda (Bombyx mori Lineu, 1758) saudáveis e infectadas por nucleopoliedrovírus

Total proteins and esterases from silk gland extracts of Bombyx mori silkworm were characterized and compared with electrophoretic profiles of prepared extracts with silkworm glands infected with nucleopolyhedrovirus (BmNPV). SDS-PAGE (7%) gels was used for the total proteins, and 10% native PAGE for esterases. In the silk glands extracts of healthy silkworms, it was observed seven protein zones with molecular weight varying between 10 kDa (P1) and 60 kDa (P7). In the infected silkworms, a new zone named P8 (90 kDa) was also detected. Esterases activity at 5th instar larvae underwent changes after the infection with BmNPV, since there was a reduction (EST-6 and EST-7) and an increase (EST-8) in the intensity of the regions of esterases activity, and specificity of EST-9 to ß-naphthyl acetate. Those alterations observed in the expression of genes after the infection with the nucleoplyhedrovirus can be used as markers to detect infections in B. mori.

Nesse estudo foram identificadas e comparadas as alterações das proteínas totais e esterases em extratos de glândula sericígena de lagartas de Bombyx mori sadias e infectadas por nucleopoliedrovírus (BmNPV), empregando eletroforese SDS-PAGE com géis a 7% para proteínas totais, e PAGE a 10% para esterases. Nos extratos de glândulas sericígenas de lagartas saudáveis, foram observadas sete regiões proteicas com peso molecular que variam entre 10 kDa (P1) a 60 kDa (P7). Naquelas infectadas pelo BmNPV, uma nova região denominada de P8 (90 kDa) foi detectada. A atividade das esterases no 5º instar larval sofreu alterações após a infecção pelo BmNPV porque houve redução (EST-6 e EST-7) e aumento (EST-8) na intensidade das regiões de atividade de esterases; e especificidade da EST-9 com o substrato ß-naftil acetato. Essas alterações na expressão gênica, após a infecção pelo nucleopoliedrovírus, poderão ser utilizadas como marcadores para detecção da infecção em B. mori.

Floral biology and behavior of Africanized honeybees Apis mellifera in soybean (Glycine max L. Merril)

Este experimento teve como objetivos avaliar a polinização realizada por abelhas Apis mellifera, estudar a biologia floral e observar o comportamento de coleta nas flores de soja (Glycine max L. Merril), variedade BRS-133 plantadas na região de Maringá-PR. Os tratamentos constituíram de áreas demarcadas de livre visitação por insetos, áreas cobertas por gaiolas, com uma colônia de abelhas (A. mellifera) no seu interior e plantas também cobertas por gaiola que impedia a visitação por insetos. Todas as áreas possuíam 24 m2 (4 m x 6 m). As flores de soja permaneceram abertas por um tempo maior (82,82 mais ou menos 3,48 horas) no tratamento coberto sem abelhas. O estigma das flores também se mostrou mais receptivo (P=0,0021) no tratamento coberto sem abelhas (87,3 mais ou menos 33 por cento) e, às 10h42min, foi o horário de maior receptividade. O pólen se manteve viável em todos tratamentos, a média foi de 99,60 mais ou menos 0,02 por cento, não apresentado diferenças entre tratamentos. O teste de fidelidade demonstrou que as abelhas A. mellifera foram 100 por cento fiéis às flores de soja. A porcentagem de aborto das flores foi de 82,91 por cento no tratamento sem abelhas e este resultado foi superior (P=0,0002) aos 52,66 por cento e 53,95 por cento dos tratamentos livre e coberto com abelhas, respectivamente. As quantidades médias de açúcar total e de glicose medidas no néctar das flores foram, respectivamente, de 14,33 mais ou menos 0,96 µg/flor e de 3,61 mais ou menos 0,36 µg/flor, não apresentando diferenças (P>0,05) entre os tratamentos. Os sólidos totais, medidos através do refratômetro manual foram de 21,33 mais ou menos 0,22 por cento no tratamento livre e de 22,33 mais ou menos 0,38 por cento no tratamento coberto com abelhas e estes resultados diferiram entre si (P=0,0001). A quantidade de néctar nas flores foram similares entre os tratamentos, sendo que o volume médio de néctar/flor foi 0,072 mais ou menos 0,04 µL/flor. As abelhas A. mellifera foram os insetos mais freqüentes (95,18 por cento). Outros insetos observados foram os lepidópteros (3,51 por cento) e outras abelhas (1,32 por cento), no tratamento livre. Neste tratamento, o tempo de coleta para néctar foi de 2,55 mais ou menos 0,07 segundos que foi menor (P=0,0039) que o tempo de 2,87 mais ou menos 0,08 segundos, observado no tratamento coberto com abelhas...

Pollination of soybean (Glycine max L. Merril) by honeybees (Apis mellifera L.)

Este experimento teve como objetivo avaliar a polinização realizada pelas abelhas na produção e qualidade das sementes da soja (Glycine max L. Merril) na região de Maringá-PR. Os tratamentos constituíram de áreas demarcadas de livre visitação por insetos, áreas cobertas por gaiolas com uma colônia de abelhas (Apis mellifera) e plantas também cobertas por gaiolas que impediam a visitação por insetos. Todas as áreas possuíam 24 m2 (4 m x 6 m), com cinco repetições cada. A produção de sementes foi maior (P=0,0001) nas áreas cobertas com abelhas e de livre visitação com um incremento na produtividade de 50,64% e 57,73%, respectivamente, em relação à área coberta sem abelhas. Pode-se considerar que as abelhas A. mellifera foram responsáveis por 95,5% da polinização realizada pelos insetos no tratamento livre. O número de vagens no tratamento coberto com abelhas foi 61,38% maior (P=0,0002) do que no coberto sem abelhas. Onde as abelhas A. mellifera foram responsáveis pela polinização cruzada, houve um aumento de 58,86% no número de sementes em relação ao tratamento onde não foi permitida a polinização realizada por insetos. Entretanto, o peso médio de 100 sementes foi maior (P=0,0001) na área coberta sem abelhas, atingiu um peso médio de 17,80 g, mostrando que plantas com menor produção formaram sementes maiores. No tratamento livre, o peso médio de 100 sementes foi de 15,26 g e no coberto com abelhas foi de 15,37 g. O teor médio de proteína bruta no grão foi de 36,69% e a média do teor de óleo foi de 20,24%. O teste de germinação não mostrou diferenças entre as sementes nos diferentes tratamentos. Pode-se concluir que as abelhas A. mellifera foram eficientes no trabalho de polinização na soja, proporcionando um aumento considerável na produção de grãos e estes resultados reforçam a necessidade do uso das abelhas A. mellifera para elevar a produtividade da soja.

Plants and pollinating bees in Maringá, State of Paraná, Brazil

The present study was carried out to survey the bees as visitors to melliferous flora in the region of Maringá, state of Paraná, Brazil. A total of 331 insects were captured, and the fauna comprised 39.88 percent Trigona spinipes, 38.37 percent Apis mellifera, 8.16 percent Tetragonisca angustula, 3.93 percent Halictidae, 1.21 percent Megachilidae, 2.42 percent Anthophoridae, and 3.32 percent other Hymenoptera. Eleven plant species from nine families were observed. The four families most frequently visited by A. mellifera were Pontederiaceae (93.53 percent), Sterculiaceae and Polygoniaceae (47.22 percent), Apocynaceae and Apiaceae (42.86 percent). The families most visited by T. spinipes were Lamiaceae (64.70 percent), Apocynaceae (57.14 percent), Sterculiaceae (51.85 percent) and Anacardiaceae (48.39 percent), and the families most visited by T. angustula were (28.57 percent), Asteraceae (22.22 percent) and Labiatae (16.47 percent). Three species predominated in number of bee visits Dombeya wallichii (32.63 percent), Ocimum americanum (15.5 percent) and Antigonon leptopus (15.2 percent). T. angustula was the most frequent visitor of O. gratissimum flowers (60.87 percent)