Relatedness and dispersal distance of eusocial bee males on mating swarms

Stingless bee males (Hymenoptera: Apidae) aggregate themselves for reproductive purposes. The knowledge of relatedness among the males attending the aggregations and the distance that they disperse from their natal nests to aggregations may provide important data to effectively conserve these bees. Here, we estimated these properties for Tetragonisca angustula (Latreille, 1811) males. Microsatellite molecular markers were used to genotype bees sampled from local nests and in mating swarms in order to identify the nests of origin of males and maternal genotypes of concerning queens. The distances from assigned nests to the mating swarms allowed us to estimate the distances travelled by males. A genetic relationship analysis was conducted to verify whether T. angustula males were closely related to nests where they aggregated. A pairwise relatedness analysis was also performed among all T. angustula males in each mating swarm. Our results demonstrated that T. angustula mating swarms received dozens to hundreds of males from several colonies (up to 70). Only two of the five mating swarms contained any males that were closely related to the bees from the new nests in construction. The relatedness among males was also extremely low. Yet, dispersal distance of T. angustula males ranged hundreds of meters up to 1.6 km, with evidence of reaching 2.25 km according to their flight radius obtained from their foraging area for locality. These data indicate a highly efficient mating system with minimal inbreeding in this bee species, with a great dispersal capability not previously found for stingless bee males.     

Variation the oviposition behavior by the stingless bee,Heterotrigona itama (Hymenoptera,Apidae, Meliponini)

A study to determine the variation of ovipositioning behavior of stingless bees, Heterotrigona itama (Cockerell, 1918) was conducted on three colonies on June 2015. A digital single-lens reflex (DSLR) camera with a macro lens attached was used to record every movement of H. itama in its colonies for 20 min hour between 0800 h and 2000 h for seven days and seven month. The daily egg laying rate and time for laying eggs in colony-B and colony-C were significantly (P ? 0.05) higher than the colony-A. However, time to close the brood was not significantly different among colonies. The fastest egg oviposition time was 4 s by the colony-B and the slowest was 6 s by the colony-A. In addition there are no significant trends on brood produced per day, laying time of eggs, and the closing time of the brood after the oviposition process from June to December 2016. This result is useful for understanding the behavior of egg laying process by the queen bees and necessary to deal with problems of management and reproduction in the near future.     

New morphological evidence supports congruent phylogenies and Gondwana vicariance for palaeognathous birds

There has been little agreement on the phylogeny of palaeognathous birds, with major differences amongst and between results from morphological and molecular data. Two recently published phylogenies using nuclear and mitochondrial DNA have substantial agreement in overall topology, with the ostrich as sister group of all other extant palaeognaths and a kiwi‐emu‐cassowary clade. Here I report a morphological phylogeny based mainly on new characters from the tongue apparatus and cranial osteology, with a theoretical ancestor as outgroup. A new interpretation of the evolution of the avian palate is included. This phylogeny is very similar to these recent molecular results; this is the first report of such congruence, and offers a credible basis for understanding the evolution of this clade. This phylogeny is fully consistent with a Gondwana vicariance model of evolution. Dates attributed from known geological events place the first extant radiation (ostrich) in the mid‐Cretaceous, and offer a means of calibration of future molecular clock investigations. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 959–983.     

Phylogenetics of the allodapine bee genus Braunsapis: historical biogeography and long-range dispersal over water

Aim A previous study of the allodapine bee genus Braunsapis suggested an African origin, with dispersal events into Madagascar and Asia, and from Asia into Australia. We re‐examine the phylogeny of this genus, using an expanded set of taxa from Madagascar and Malawi and additional sequence data, in order to determine the number of dispersals and the timeframe over which they occurred. Location Africa, Madagascar, Malawi, Asia and Australia. Methods One nuclear (EF‐1α F2) and two mitochondrial (CO1 and Cyt b) gene regions were sequenced for 36 allodapine bee species (including members of the genera Braunsapis, Nasutapis, Allodape, Allodapula, and Macrogalea) and one ceratinine species (Ceratina japonica). We used Bayesian analyses to examine phylogenetic structure and a penalized likelihood approach to estimate approximate ages for key divergences in our phylogeny. Results Our analyses indicate a tropical African origin for Braunsapis in the early Miocene followed by very early dispersal into Asia and then a subsequent dispersal, following Asian diversification, into Australia during the late Miocene. There have also been two dispersals of Braunsapis from Africa to Madagascar and this result, when combined with phylogenetic and biogeographical data for other allodapines, suggests that these bees have the ability to cross moderately large ocean expanses. These dispersals may have been aided by the West Wind Drift, but rafting across the Mozambique Channel is also possible, and could be aided by the existence of developmental stages that require minimal or no feeding and by tolerance to sea water and spume. Accumulating evidence suggests that many biogeographical patterns in the southern hemisphere may be better explained by dispersal than by Gondwanan vicariance hypotheses. Our results add to this growing body of data and raise the possibility that some puzzling trans‐Indian Ocean distributions may also be explained by historical dispersal events across oceanic barriers that now seem insuperable.     

Global dispersal and ancient cryptic species in the smallest marine eukaryotes

Small eukaryotic species (<1 mm) are thought to behave as prokaryotes in that, lacking geographical barriers to their dispersal due to their tiny size, they are ubiquitous. Accordingly, the absence of geographical insulation would imply the existence of a relatively small number of microeukaryotic species. To test these ideas, we sequenced and compared several nuclear, mitochondrial, and chloroplast genes from the isolates of a marine picoeukaryotic alga (approximately 2 microm), Micromonas pusilla, collected worldwide. Independent and combined phylogenetic analyses demonstrate that this traditional single morphospecies actually comprises several independent lineages, some of which are shown to be ubiquitous in oceans. However, while some lineages group closely related strains, others form distant clusters, revealing the existence of cryptic species. Moreover, molecular dating using a relaxed clock suggests that their first diversification may have started as early as during the Late Cretaceous (approximately 65 MYA), implying that "M. pusilla" is the oldest group of cryptic species known to date. Our results illustrate that global dispersal of a picoeukaryote is possible in oceans, but this does not imply a reduced species number. On the contrary, we show that the morphospecies concept is untenable because it overlooks a large genetic and species diversity and may lead to incorrect biological assumptions.     

Colony foraging allocation is finely tuned to food distance and sweetness even close to a bee colony

Social bee colonies can allocate their foraging resources over a large spatial scale, but how they allocate foraging on a small scale near the colony is unclear and can have implications for understanding colony decision‐making and the pollination services provided. Using a mass‐foraging stingless bee, Scaptotrigona pectoralis (Dalla Torre) (Hymenoptera: Apidae: Meliponini), we show that colonies will forage near their nests and allocate their foraging labor on a very fine spatial scale at an array of food sources placed close to the colony. We counted the foragers that a colony allocated to each of nine feeders containing 1.0, 1.5, or 2.0 M sucrose solution [31, 43, and 55% sucrose (wt/wt), respectively] at distances of 10, 15, and 20 m from the nest. A significantly greater number of foragers (2.6–5.3 fold greater) visited feeders placed 10 vs. 20 m away from the colony. Foraging allocation also corresponded to food quality. At the 10‐m feeders, 4.9‐fold more foragers visited 2.0 M as compared to 1.0 M sucrose feeders. Colony forager allocation thus responded to both differences in food distance and quality even when the travel cost was negligible compared to normal colony foraging distances (10 m vs. an estimated 800–1 710 m). For a nearby floral patch, this could result in unequal floral visitation and pollination.     

Foragers of the stingless bee Plebeia droryana inform nestmates about the direction,but not the distance to food sources

1. The tropical stingless bees have evolved intricate communication systems to recruit nestmates to food locations. Some species are able to accurately communicate the location of food, whereas others simply announce the presence of food in the environment.
2. Plebeia droryana is a tiny Neotropical stingless bee that, until recently, was thought to use a solitary foraging strategy, that is without the use of a recruitment communication system. However, recent research has indicated that P. droryana might be able to recruit nestmates to specific food source locations.
3. We tested this by studying whether foragers can guide nestmates in the direction and the distance of artificial feeders placed in the vicinity of the colony. We trained bees to a scented sucrose solution feeder at 10 m and placed different feeders either in different directions (experiment 1) or in different distances (experiment 2). We found that P. droryana directs newcomers in the right direction, but distance information does not seem to be communicated.
4. Moreover, we then tested whether newcomers use chemical and visual cues originating from nestmates foraging at the food source, but found no evidence for the use of these social cues provided by conspecifics.
5. The potential mechanism that P. droryana may use to orient recruits toward the food source, however, remains unknown and requires further study.

     

Multiple nuclear genes and retroposons support vicariance and dispersal of the palaeognaths,and an Early Cretaceous origin of modern birds

The origin and timing of the diversification of modern birds remains controversial, primarily because phylogenetic relationships are incompletely resolved and uncertainty persists in molecular estimates of lineage ages. Here, we present a species tree for the major palaeognath lineages using 27 nuclear genes and 27 archaic retroposon insertions. We show that rheas are sister to the kiwis, emu and cassowaries, and confirm ratite paraphyly because tinamous are sister to moas. Divergence dating using 10 genes with broader taxon sampling, including emu, cassowary, ostrich, five kiwis, two rheas, three tinamous, three extinct moas and 15 neognath lineages, suggests that three vicariant events and possibly two dispersals are required to explain their historical biogeography. The age of crown group birds was estimated at 131 Ma (95% highest posterior density 122–138 Ma), similar to previous molecular estimates. Problems associated with gene tree discordance and incomplete lineage sorting in birds will require much larger gene sets to increase species tree accuracy and improve error in divergence times. The relatively rapid branching within neoaves pre-dates the extinction of dinosaurs, suggesting that the genesis of the radiation within this diverse clade of birds was not in response to the Cretaceous–Paleogene extinction event.     

Electroantennogram and behavioral responses of workers of the stingless bee Oxytrigona mediorufa to mandibular gland volatiles

Gas chromatography-mass spectrometric analysis showed that the mandibular gland secretion of workers of the stingless bee Oxytrigona mediorufa (Cockerell) (Hymenoptera: Apidae) is composed of 3-hepten-2,5-dione, 3-nonene-2,5-dione, 2-heptanone, hydrocarbons, tetradecyl, and hexadecyl acetates and minor compounds related to these. Behavioral and electroantennographic tests were carried out on conspecific workers to observe the effect of worker mandibular gland secretion, individual compounds (2-heptanone, 2-nonanone, and tetradecyl acetate), and a blend of these three. Bioassays showed that biting responses of O. mediorufa to the odor of the mandibular gland secretion were similar to that of 2-heptanone and to the three-component blend. Oxytrigona mediorufa workers exhibited antennal olfactory responses to the gland extract, 2-heptanone, and the synthetic mixture. The function of the mandibular gland secretion and 2-heptanone is discussed in terms of an alarm pheromone and defensive substances.     

Patterns of animal dispersal, vicariance and divsrsification in the Holarctic

We analysed patterns of animal dispersal, vicariance and diversification in the Holarctic based on complete phylogenies of 57 extant non‐marine taxa, together comprising 770 species, documenting biogeographic events from the Late Mesozoic to the present. Four major areas, each corresponding to a historically persistent landmass, were used in the analyses: eastern Nearctic (EN), western Nearctic (WN), eastern Palaeoarctic (EP) and western Palaeoarctic (WP). Parsimony‐based tree fitting showed that there is no significantly supported general area cladogram for the dataset. Yet, distributions are strongly phylogenetically conserved, as revealed by dispersal‐vicariance analysis (DIVA). DIVA‐based permutation tests were used to pinpoint phylogenetically determined biogeographic patterns. Consistent with expectations, continental dispersals (WP?EP and WN?EN) are significantly more common than palaeocontinental dispersals (WN?EP and EN?WP), which in turn are more common than disjunct dispersals (EN?EP and WN?WP). There is significant dispersal asymmetry both within the Nearctic (WN→EN more common than EN→WN) and the Palaeoarctic (EP→WP more common than WP→EP). Cross‐Beringian faunal connections have traditionally been emphasized but are not more important than cross‐Atlantic connections in our data set. To analyse changes over time, we sorted biogeographic events into four major time periods using fossil, biogeographic and molecular evidence combined with a ‘branching clock’. These analyses show that trans‐Atlantic distributions (EN‐WP) were common in the Early‐Mid Tertiary (70‐20 Myr), whereas trans‐Beringian distributions (WN‐EP) were rare in that period. Most EN‐EP disjunctions date back to the Early Tertiary (70‐45 Myr), suggesting that they resulted from division of cross‐Atlantic rather than cross‐Beringian distributions. Diversification in WN and WP increased in the Quaternary (< 3 Myr), whereas in EP and EN it decreased from a maximum in the Early‐Mid Tertiary.     

Dispersal, vicariance, and timing of diversification in Nothonotus darters

The species diversity of North American freshwater fishes is unparalleled among temperate regions of the planet. This diversity is concentrated in the Central Highlands of eastern North America and this distribution pattern has inspired different models involving either dispersal or vicariance to explain the high species diversity of North American fishes. The most popular of these models is the Central Highlands vicariance hypothesis (CHVH), which proposes an ancient and diverse widespread fauna that existed across a previously continuous highland landscape that is much different from today. The mechanisms of isolation in the CHVH involve specific instances of vicariance that affected several diverse lineages of Central Highlands fishes. We tested predictions of the CHVH and alternative models using a cytochrome b-inferred phylogeny of the darter clade Nothonotus. A Bayesian mixed-model method was used for phylogenetic analysis. The phylogenetic data set included all 20 recognized Nothonotus species, and most species were represented with multiple sequences. We were able to convert genetic branch lengths to absolute age using external fossil calibrations in the freshwater perciform fish clade Centrarchidae. Using a well-resolved Nothonotus phylogeny and divergence time estimates, we identify equal numbers of instances of both vicariance and dispersal among disjunct regions of the Central Highlands, biogeographic pseudocongruence, rather recent speciation in Nothonotus, and a surprisingly large amount of speciation within highland areas. With regard to Nothonotus, previous Central Highlands biogeographic models offer little in the way of providing possible mechanisms responsible for diversification in the clade. Patterns of speciation in Nothonotus are similar to those discovered in recent efforts that have included speciation as a parameter into classic models of island biogeography.     

Allometric and multivariate analysis of sex and caste polymorphism in the neotropical stingless bee,Scaptotrigona postica

Summary Morphometric data obtained from natural andin vitro-rared queens, workers, and drones of the stingless bee.Scaptotrigona postica were subjected to allometric and multivariate tests to study sex- and caste-related growth patterns. As imaginai phenotype variation appears to be restricted in members of a normal colony, the inclusion ofin vitro-reared individuals permitted an analysis of a considerably wider size range for each morph, and proved important for the calculation of reliable regression statistics in the allometric analyses. Our results show that essentially no individuals with a mixture or transition of sex or caste traits are produced, and, consequently, that for most morphometric characters, queens, workers, and drones lie on different regression lines. Hence, workers cannot be considered as masculinized females, as has been suggested in studies based exclusively on multivariate analyses. Instead, the various morphs may result from a stepwise programming and reprogramming of a few growth rule parameters during critical stages of preimaginal development, and complex hypothetical shifts in the balance of maleness and femaleness genes need not be assumed. A multivariate discriminant analysis, on the other hand, proved to be an efficient tool for the selection of diagnostic size characters.Dedicated to Warwick Estevam Kerr, the Brazilian pioneer of stingless bee genetics, on the occasion of his 70th birthday, September 9, 1992.     

Cytotoxicity effect of honey,bee pollen,and propolis from seven stingless bees in some cancer cell lines

Our effort to find new material for anti cancer from natural resources leads us to focus on stingless bee products such as honey, bee pollen, and propolis. The products were from seven stingless bees named Homotrigona fimbriata, Heterotrigona itama, Heterotrigona bakeri, Tetragonula sarawakensis, Tetragonula testaceitarsis, Tetragonula fuscobalteata, Tetragonula laeviceps. The stingless bee products were evaluated for their cytotoxicity effect on MCF-7, HeLa and Caco-2 cancer cell lines. This is the first time to be reported that the honey, ethanol extracts of bee pollen and propolis of H. fimbriata displayed more potent cytotoxicity than other stingless bee products. By chromatography and biological activity-guided fractionation, ethanol extract of propolis from H. fimbriata was fractionated and isolated its active compound named mangiferonic acid. Mangiferonic acid showed a cytotoxicity effect with IC₅₀ values 96.76 µM in MCF-7, >110.04 µM in HeLa, and > 110.04 µM in Caco-2, respectively. These results exhibited the potential of ethanol extracts from propolis of H. fimbriata to be further developed for drug and experiments to verify the function are essential.     

Early Tertiary out-of-India dispersal of Crypteroniaceae: evidence from phylogeny and molecular dating

Abstract.— Pylogenetic analyses and molecular dating estimates based on chloroplast DNA sequences were used to establish the relationships of the southern and Southeast Asian Crypteroniaceae and elucidate their biogeographic history. Maximum parsimony and likelihood analyses of rbc L sequences suggested that Crypteroniaceae should be restricted to Crypteronia , Axinandra , and Dactylocladus and that Crypteroniaceae, so defined, are sister to a clade formed by three small African taxa (Oliniaceae, Penaeaceae, and Rhynchocalycaceae) and the monotypic Central and South American Alzateaceae. Three molecular dating approaches (maximum-likelihood under a molecular clock, Langley-Fitch, and penalized-likelihood) were used to infer the age of Crypteroniaceae using both paleobotanic and geologic calibrations. Comparisons among these three methods revealed significant lineage effects in rbc L sequences. Clock-independent dating estimates suggested that divergence of Crypteroniaceae from its African and South American relatives coincided with the breakup of Gondwana, and that India likely served as a "raft" transporting Crypteroniaceae to Asia, with later expansion to Southeast Asia. To our knowledge, Crypteroniaceae are the first plant group for which the out-of-India hypothesis is well corroborated by molecular-based estimates of divergence times.