Apidologie最新文献

The stingless bee genus Trigona includes 32 species, exclusive to the New World, which are grouped into two clades (A and B) according to phylogenetic molecular data. Cytogenetic studies have been performed in only seven Trigona taxa, and molecular cytogenetic data are available for only one species. These studies have been important for the chromosomal characterization of the species; however, discussions focusing on the karyotype evolution of Trigona in a phylogenetic context are lacking. In this study, we characterized the karyotype, through classical and molecular cytogenetics, of five Trigona species: T. pallens and T. williana, from clade A, and T. hypogea, T. aff. fuscipennis, and T. truculenta, from clade B, in order to provide insights into the karyotype evolution in Trigona and investigate whether the analyzed cytogenetic markers may have a phylogenetic signal. All five Trigona species have 2n = 34 chromosomes. Variations in the karyotype formula were observed in T. truculenta and T. hypogea compared with the other three species. Although heterochromatin distribution was restricted to one of the arms in most of the chromosomes of the five species, C-banding experiments highlighted a lower degree of heterochromatin compaction in T. pallens and T. williana. The microsatellite (GA)₁₅ was exclusively located in the euchromatic regions of the chromosomes in all five species. The number of pairs bearing rDNA genes varied among the species studied, and this cytogenetic trait seems to reflect the phylogeny, separating the species into two clades. This study showed interspecific variations to a greater or lesser degree among Trigona species, highlighting the intense chromosomal evolutionary dynamics in the genus.

The parasitic mite Varroa destructor (Anderson & Trueman) spends the dispersal phase of its life cycle on adult honeybees (Apis mellifera L.). The meaning of this phase for both bees and mites is still not well understood. This especially applies to prolonged dispersal phases as a result of brood interruptions. Hence, it is highly important to unravel this phase for understanding the underlying biological mechanisms and implementing this knowledge in beekeeping practice and research efforts. We investigated the effects of brood interruptions on honeybee colonies and the mites naturally infesting them. Reproduction parameters, brood infestation and recapping frequency were monitored over 60 days after brood interruptions of varying durations. Our results show that recapping frequency and mite non-reproduction increased during the interruption of egg laying. The duration of interruption and the time elapsed afterwards additionally affected the occurrence of reproductive failure. Hence, the reproduction of mites was affected by brood breaks immediately and in the long run.

Stingless bees collect plant latex and resin to produce cerumen and propolis. Cerumen is primarily used for nest construction, such as brood cells, storage pots, and involucrum. Propolis is mainly used as a sealing material and for predator and pathogen defense. Knowledge about the botanical origin of these materials is vital for sustainable bee management. We performed (i) direct observation method by field surveys and (ii) indirect assumption method via pollen analysis of corbicular and in-hive stored latex/resin, cerumen, and propolis of Tetragonula iridipennis. By the direct observation method, we identified 25 plant species as latex/resin sources of the stingless bees; frequently encountered were Artocarpus heterophyllus, Calotropis gigantea, Ficus benghalensis, Ficus religiosa, Mangifera indica, Tabernaemontana divaricata, and Vachellia nilotica. From pollen analyses, we found diverse pollen types, including pollens of polleniferous plants. Comparatively higher pollen content was found in cerumen and propolis samples than in the in-hive stored latex/resin and corbicular latex/resin loads. But all the pollen types do not indicate actual latex/resin sources for the bee species. These pollen types came from the foraging environment and additionally during the transport of latex/resin within the hive and the processing of latex/resin into cerumen and propolis. Therefore, we can conclude that the pollen content of corbicular and in-hive stored latex/resin, cerumen, and propolis is not truly inferring its botanical origin; it requires alternative techniques like the direct observation method or chemical profiling.

Plant-bee networks are rarely, if ever, studied quantitatively at continental scales, yet these have the potential to inform how biota and ecosystems are assembled beyond narrower regional biomes. The short-tongued bee family Colletidae comprises the major component of bee diversity in Australia, with three key subfamilies: the Neopasiphaeinae, Hylaeinae, and Euryglossinae. We use museum data (> 27,000 records) to record binary interactions between these bees (from each of these subfamilies, resolved to subgenera) and plants (resolved to genera). The resulting networks were analysed using bipartite graphs and associated indices of network structure. The three bee subfamilies showed markedly different network structures with their floral hosts. Euryglossinae had strong interactions with Myrtaceae and an otherwise relatively narrow host breadth, Neopasiphaeinae had little signal of host specialisation above genera and a very broad host breadth, and Hylaeinae appeared intermediate in network structure. Furthermore, Euryglossinae is more speciose within Australia (404 species, or ~ 25% of described Australian bee fauna) than Hylaeinae and Neopasiphaeinae, but these differences do not correspond to the stem ages of the three subfamilies, suggesting that time-since-origin does not explain bee species diversity or floral host breadth. Patterns of host breadth persist after rarefaction analyses that correct for differing numbers of observation records. We suggest that visitation networks could be influenced by evolutionary constraints to expansion of floral host breadth, but it is also possible that many bee-plant interactions are shaped by bees exploiting floral traits that are driven by non-bee fauna operating at large biogeographical scales.

Floral choice by bees is influenced by the bees’ previous experience with flowers. For example, bees may learn to associate particular flower colours with rewards and prefer flowers of that colour in a given patch. In this study, we assessed whether floral choice by the stingless bee Tetragonula carbonaria was influenced by colour similarity to a high-quality neighbour flower, while it contained nectar, and then when it was empty of nectar. We trained T. carbonaria to visit highly rewarding artificial flowers (50% (v/v) honey solution) within a patch that also contained two types of less-rewarding artificial flowers (20% (v/v) honey solution): one of the same colour (though different pattern) as the high-quality flower and one a different colour (and pattern) to the other two flowers. Colonies were tested with blue and yellow colour sets, where either the blue flower was most rewarding and the yellow the least, or vice versa. We then compared preferences between the two equal-quality flowers in the patch under two conditions: (i) when nectar was available from the high-quality flower, and (ii) when the nectar was removed from the high-quality flower. We found that, when available, high-quality flowers were always visited more than low-quality flowers. Under this condition, adjacent lower-quality flowers in the patch received similar levels of visitation, regardless of their colour. When the reward was removed from the high-quality flower (simulating an emptied flower), foragers quickly switched to using the remaining two equal-quality flowers in the patch, but again showed no preference for the similar-coloured flower. Our results indicate that T. carbonaria are adaptable foragers capable of quickly learning and responding to floral reward changes in their foraging environment. At least under our experimental conditions, we found no evidence that T. carbonaria floral choice is influenced by colour similarity to a high-quality resource in the same foraging location.

Abstract

Varroa is a major world-wide pest to Western honey bees (Apis mellifera), causing huge ongoing losses of colonies every year. Conversely, the Eastern honey bee (Apis cerana) is less vulnerable to the mite having existed alongside it over a long evolutionary period. Research conducted during the 1980s and 1990s, shortly after Varroa had spread across the globe, concluded that the Eastern honey bee was less vulnerable because it displayed higher levels of grooming behaviour, brood removal behaviour and mite infertility than its Western counterpart. However, this review on these Varroa resistance traits in A. cerana indicates that there is surprisingly little evidence for these conclusions. This review explores this evidence and discusses the potential flaws in the studies and the gaps that still remain in our knowledge of Varroa resistance traits in A. cerana.

Odorant-binding proteins (OBPs) in insects bind to volatile chemical cues that are important in regulating insect behavior. It is hypothesized that OBPs bind with specificity to certain volatiles and may help in transport and delivery to odorant receptors (ORs), and may help in buffering the olfactory response and aid the insect in various behaviors. Honeybees are eusocial insects that perceive olfactory cues and strongly rely on them to perform complex olfactory behaviors. Here, we have identified and annotated odorant-binding proteins and few chemosensory proteins from the genome of the dwarf honey bee, Apis florea, using an exhaustive homology-based bioinformatic pipeline and analyzed the evolutionary relationships between the OBP subfamilies. Our study confirms that the Minus-C subfamily in honey bees has diverged from the Classic subfamily of odorant-binding proteins.