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Female mating frequency varies. Determining the causes of this variation is an active research area. We tested the hypothesis that in stingless bees, Meliponini, singlemating is due to the execution of queens that make a matched mating at the complementary sex determination locus and have diploid male offspring. We studied the Brazilian species Scaptotrigona depilis. We made up 70 test colonies so that 50% (single matched mating), 25% (double mating), 12.5% (quadruple mating), or 0% (single nonmatched mating) of the emerging brood were diploidmales.Queen execution following diploidmale emergence was equal and high in colonies producing 50% (77% executed) and 25% (75%) diploid males versus equal and low in colonies producing 12.5% (7%) and 0% (0%) diploid males. These results show that queens that mate with two males with similar paternity suffer an increased chance of being executed, which selects against double mating. However, double mating with unequal paternity (e.g., 25∶75), which occasionally occurs in S. depilis, is selectively neutral. Single mating and double mating with unequal paternity form one adaptive peak. The results show a second adaptive peak at quadruple mating. However, this is inaccessible via gradual evolutionary change in a selective landscape with reduced fitness at double mating.

Bees of the Meliponini tribe (Hymenoptera, Apidae), known as stingless bees, comprise one of the most important groups of pollinators of the tropical flora (Michener, 2007). Its ecological importan...

Most flying animals rely primarily on visual cues to coordinate and control their trajectory when landing. Studies of visually guided landing typically involve animals that decrease their speed before touchdown. Here, we investigate the control strategy of the stingless beeScaptotrigona depilis, which instead accelerates when landing on its narrow hive entrance. By presenting artificial targets that resemble the entrance at different locations on the hive, we show that these accelerated landings are triggered by visual cues. We also found thatS. depilisinitiated landing and extended their legs when the angular size of the target reached a given threshold. Regardless of target size, the magnitude of acceleration was the same and the bees aimed for the same relative position on the target suggesting thatS. depilisuse a computationally simple but elegant ‘stereotyped' landing strategy that requires few visual cues.

Bees are essential pollinators on earth, supporting forest equilibrium and human agriculture. The chemistry of the stingless bee–plant symbiosis is a complex and not completely understood phenomenon. Here, we combined untargeted tandem mass spectrometry, molecular networking, and multivariate statistical analysis to investigate the chemical diversity in colonies of the stingless bee Scaptotrigona depilis. Flavonoids were the most representative and diverse group of plant metabolites detected, indicating the importance of these biologically active natural products to the bees. We unveiled the metabolome, mapped the distribution of plant metabolites in stingless bee colonies, and digitized the chemical data into a public database.

Partamona helleri stingless bees construct a unique, funnel-shaped entrance that resolves an evolutionary conflict between foraging efficiency and defence. The large outer entrance allows many foragers to pass while the narrow inner entrance requires few guards to defend. This structure has given rise to a remarkable behaviour in returning foragers, which appear to approach the nest entrance at high speed and ‘crash’ head first into the entrance. We compared P. helleri landing behaviour with two related species with architecturally different entrances that land conventionally using their legs: Melipona scutellaris, whose narrow entrance allows only a single bee to pass, and Scaptotrigona depilis, which has a wide entrance tube. All three species initially decelerated on their approach to the nest entrance. However, 0.2 m from the entrance P. helleri began accelerating, whereas the other species continued to decelerate. Partamona helleri entered its nest at 1.14 ms−1, double the velocity of the other species. Despite its greater velocity, P. helleri made no fewer errors than the other species when attempting to enter its nest, probably by virtue of the large target provided by the outer entrance. We then used a bioassay that suggests that this behaviour is a defence against ambush predators at the nest entrance. Finally, we use a scaling argument to show that the crash impact should not cause any damage to a small animal such as a bee, such that no morphological adaptation is required.

The sex determination system in the eusocial stingless bees (Apidae, Meliponini) is based on the combination of alleles at the complementary sex determination (CSD) locus. In this system, males are haploid and females are diploid. However, diploid males can develop from fertilized eggs when they are homozygous at single or multiple sex loci. The production of such males can negatively affect population viability, since they are usually infertile or inviable. Moreover, when they are viable but infertile, or siring sterile triploid offspring, this could cause another load on the population, leading the fertilized offspring of other females to be only haploid males or triploid sterile daughters. In this context, our aim was to verify whether diploid males of the stingless bee Scaptotrigona depilis do in fact join reproductive aggregations. We showed that of 360 marked males from two different colonies, five were participating in a reproductive aggregation ca. 20 meters from their natal colonies. Using microsatellites markers, it was confirmed that three of these five males were diploid. They were captured in the mating aggregations when they were 15 to 20 days old. Further research is necessary to determine the mating success of stingless bee diploid males under natural conditions and to determine their impact on stingless bee population extinction risks. JHR 45: 125–130 (2015) doi: 10.3897/JHR.45.4769 http://jhr.pensoft.net Copyright Ayrton Vollet-Neto et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. SHORT COMMUNICATION Ayrton Vollet-Neto et al. / Journal of Hymenoptera Research 45: 125–130 (2015) 126

To land, flying animals must simultaneously reduce speed and control their path to the target. While the control of approach speed has been studied in many different animals, little is known about the effect of target size on landing, particularly for small targets that require precise trajectory control. To begin to explore this, we recorded the stingless beesScaptotrigona depilislanding on their natural hive entrance—a narrow wax tube built by the bees themselves. Rather than decelerating before touchdown as most animals do,S. depilisaccelerates in preparation for its high precision landings on the narrow tube of wax. A simulation of traffic at the hive suggests that this counterintuitive landing strategy could confer a collective advantage to the colony by minimizing the risk of mid-air collisions and thus of traffic congestion. If the simulated size of the hive entrance increases and if traffic intensity decreases relative to the measured real-world values, ‘accelerated landing' ceases to provide a clear benefit, suggesting that it is only a useful strategy when target cross-section is small and landing traffic is high. We discuss this strategy in the context ofS. depilis' ecology and propose that it is an adaptive behaviour that benefits foraging and nest defence.

International audience; Stingless bees are a diverse group of highly eusocial tropical bees and potential pollinators of natural and crop environments. Nevertheless, large-scale breeding for agricultural purposes still needs development. A bottleneck is the small number of queens generally found in the colonies of most species. A proposed solution is to develop in vitro rearing of stingless bee queens, which includes a technical support due to the massive liquid feeding of larvae. In this study, we tested the efficacy of in vitro queen-rearing techniques in terms of queen size, survival, and fecundity. We found that humidity must be kept high during the first 6 days of larval development and reduced thereafter to 75 %. In the most effective treatments, we obtained up to 97.9 % queen survival. We also found that queens not different in size from natural queens could be produced if sufficient larval food is provided. In vitro queens were able to mate and lay viable eggs. This methodology is also useful for several research appliances, like pesticide effect on bees, pollen quality effect in caste determination, and the use of genetic sources for selection programs, among others.

We announce the complete genome sequence of Bacillus sp. strain SDLI1, isolated from larval gut of the stingless bee Scaptotrigona depilis . The 4.13-Mb circular chromosome harbors biosynthetic gene clusters for the production of antimicrobial compounds.

International audience; AbstractIn this study, we investigate the behavioural response of the highly eusocial stingless bee Scaptotrigona depilis to high temperatures. We found that nest temperature in the brood area can be up to 2.5 °C lower relative to a control empty box during hot periods. We showed that high temperatures increase both water collection and wing fanning behaviour at the colony level, suggesting that these behaviours are adaptations to cooling the nest in this species. Additionally, we measured survival and development time of pupae incubated at five different constant temperatures (22, 26, 30, 34 and 38 °C). We found that the development time of S. depilis brood significantly varied between treatments and had a strong negative correlation with temperature. Brood survived over a large range of incubation temperatures; however, extreme temperatures (22 and 38 °C) were almost 100 % lethal, highlighting the importance of thermoregulation, at least in extreme conditions.

A meliponiculture project in Amboro National Park, Southeast Bolivia, uses six species of stingless bees: “erereu choca” Melipona brachychaeta, “erereu barcina” Melipona grandis, “obobosi” Scaptotrigona depilis, “suro negro” Scaptotrigona polysticta, “suro choco” Scaptotrigona near to xanthotricha, and “senorita” Tetragonisca fiebrigi. The annual yield of stingless bee products (honey, pollen, propolis) is provided here. We also studied the pot honey produced by these species, chemistry (moisture, ash, pH, free acidity, reducing sugars, sucrose), mineral contents (Ca, Cu, Fe, K, Mg, P, Zn), microbes (mesophilic bacteria, molds, yeasts), human sensory responses to selected components, and networking needed for marketing considerations.

The aim of this study is to determine the chemical composition of propolis collected by stingless bees. For this purpose eight ethanol extracts of propolis collected by Melipona favosa from Venezuela, Melipona grandis, Scaptotrigona depilis, and Scaptotrigona polysticta from Bolivia, and Tetragonula biroi from Philippines were prepared and analyzed. According to gas chromatography–mass spectrometry (GC–MS) results, aliphatic acids and their esters, alcohols, aromatic acids and their esters, hydrocarbons and terpenes were identified from propolis samples. All three Venezuelan propolis include clay. Bolivian propolis include more components than propolis from the Philippines. We found kaur-16-ene (8 beta,13 beta), olean-12-ene, 3-keto-urs-12-ene in propolis collected by stingless bees, as new compounds observed only in Bolivian propolis.

We describe a case of a spontaneously established mixed colony of two species of stingless bees. The host colony of Scaptotrigona depilis, an aggressive bee that forms large colonies, was invaded by workers of Nannotrigona testaceicornis, a smaller bee that forms small colonies. The host colony and the invading species colony were maintained in next boxes about 1.5 m apart. The N. testaceicornis colony had been recently divided. Observations were made daily for 10 min, and every two weeks the colony was opened for observations within the nest. Initially the host colony bees repulsed the invading species, but as their numbers built up, they were no longer able to defend the entrance. An estimated 60-90 N. testaceicornis workers lived integrated into the colony of S. depilis for 58 days. During this period, they reconstructed and maintained the entrance tube, changing it to an entrance typical of N. testaceicornis. They also collected food and building material for the host colony. Nannotrigona testaceicornis tolerated transit of S. depilis through the entrance, but did not allow the host species to remain within the tube, though the attacks never resulted in bee mortality. Aggression was limited to biting the wings; when the bees fell to the ground they immediately separated and flew back. There have been very few reports of spontaneously occurring mixed stingless bee colonies. It is difficult to determine what caused the association that we found; probably workers of N. testaceicornis got lost when we split their colony, and then they invaded the colony of S. depilis.

Submitted by Repositorio Institucional (repositorio@ufgd.edu.br) on 2018-10-10T14:59:02Z No. of bitstreams: 1 MarcosGoncalvesFerreira.pdf: 540413 bytes, checksum: 9a877368cdb8af364621cf4db298f035 (MD5) Made available in DSpace on 2018-10-10T14:59:02Z (GMT). No. of bitstreams: 1 MarcosGoncalvesFerreira.pdf: 540413 bytes, checksum: 9a877368cdb8af364621cf4db298f035 (MD5) Previous issue date: 2008-03-25 Foram identificados os polens coletados por operárias de Scaptotrigona depilis (Moure, 1942), na Região de Dourados-Ms, durante o período de setembro de 2006 a agosto de 2007. Ao todo foram coletados 43 tipos polínicos, onde os polens mais representativos, em números de espécies, foram da família Myrtaceae (Eucalyptus spp.) e Leguminosae (Mimosoideae e Caesalpinoideae). Os picos para os valores de amplitude do nicho trófico (H’) evidenciados nos meses de Setembro (2,32), Novembro (2,29) e Outubro (2,02) mostraram que a abelha pode ser generalista, desde que, haja a disponibilidades de recursos, e que esses recursos reúnam características que sejam atrativas para a coleta dessa abelha. Os valores para equitatividade (J’) mostraram que esses meses também foram mais uniformes chegando ao seu valor máximo no mês de Setembro (1) revelando uma coleta mais homogenia de recursos. Os fatores ambientais (temperatura, umidade relativa e pluviosidade) não mostraram uma relação direta com abelha, sendo importante, porém quando atingem valores extremos, contudo esses fatores parecem estar mais relacionados com os ciclos diários ou sazonais de produção de pólen e néctar do que diretamente com as atividades de coleta da abelha. Pollen collected by workers of Scaptotrigona depilis (Moure, 1942) were identified in the region of Dourados, Mato Grosso do Sul, during the period of September, 2006 to August, 2007. From the 43 types of pollen collected , the more representative ones during this period were those from the Myrtaceae (Eucalyptus spp.) and Leguminosae (Mimosoideae and Caesalpinoideae) family. The peaks for the values of the trophic niche breadth (H ') evidenced in the months of September (2,32), November (2,29) and October (2,02), showed that bees can be generalist, provided that there are availabilities of resources, and that these resources possess characteristics that are attractive to the pollen collection by the bees. The values for equitability (J ') showed that these months were also more uniforms reaching its maximum value in September (1) disclosing a homogenous collection of resources. The meteorological features (temperature, relative humidity and rainfall) did not show a direct relation to floral use, being important, however, when they reach extreme values, though these factors seem to be more related to the daily or seasonal cycles of pollen and nectar production than directly to the collection activities of the bees.

SummaryThree semi-artificial diets for Scaptotrigona depilis were devised and tested for use during times of pollen shortage. Diet 1 consisted of brewer's yeast and 50% sucrose. Diet 2 consisting of 20 g brewer's yeast, 1·5 g pollen from the colony, and 30 ml 50% commercial sucrose was allowed to ferment for 15 days at 28 to 30°C. Diet 3 was the same as Diet 2 but was not allowed to ferment. A control group received pollen from the colony and 50% commercial sucrose.Based on analysis of hypopharyngeal gland acini and on oocyte size, Diet 2 appeared to be a good substitute for the natural food of the species.

Determiner les besoins minimaux et les concentrations adequates de nourriture est utile pour maintenir les colonies en bonnes conditions tout au long de l'annee et mettre au point des regimes artificiels pour l'espece etudiee. Le travail presente avait pour but de determiner: 1) la quantite minimale de pollen necessaire au developpement normal des glandes hypopharyngiennes (HPG) et des ovocytes chez les ouvrieres de Scaptotrigona depilis et 2) les meilleures concentrations des solutions de glucose, fructose, saccharose et maltose pour la meme espece. Dans les 2 cas on a utilise des ouvrieres naissantes (0-24 h)