Endemic Bees Research Articles

African endemic stingless bees as an efficient alternative pollinator to honey bees in greenhouse cucumber (Cucumis sativus L)

The current honey bee decline necessitates the use of alternative native pollinators to ensure global food security. Here, we compared the pollination behaviour and efficiency of the African honey bee (Apis mellifera) and six African endemic Meliponini (Meliponula bocandei, Dactylurina schmidti, Meliponula lendliana, Hypotrigona gribodoi, Meliponula ferruginea and Meliponula togoensis) in a greenhouse with the non-parthenocarpic cucumber variety Super Marketer. Honey bees and D. schmidti started foraging on introduction in the greenhouse, while M. lendliana and M. togoensis showed the longest delay. In most species, foragers collected nectar and pollen, excepting M. bocandei that specialized in nectar collection, and H. gribodoi and M. togoensis, specialized in pollen collection. African honey bees visited flowers the shortest, while H. gribodoi and D. schmidti had a 2-fold probing time, on average. Most stingless bees species had a lower hive activity with fewer foragers encountered per hour than for honey bees, except D. schmidti. M. bocandei, M. ferruginea, A. mellifera scutellata and H. gribodoi, yielded a seed germination percentage of around 90%. M. lendliana, M. togoensis and D. schmidti yielded a much lower seed germination percentage around 30%, which indicates that the quality of pollination was remarkably lower by using these three species. The highest sugar content was recorded in fruits from flowers pollinated by M. bocandei, African honey bees, D. schimdti or M. togoensis with the same solid content as the gold standard method, i.e., hand cross-pollination. We found that M. bocandei was the most efficient cucumber pollinator of all species tested: because pollination by this species yielded the largest and heaviest fruits and the highest seed numbers.

Ensemble Models Predict Invasive Bee Habitat Suitability Will Expand under Future Climate Scenarios in Hawai'i.

Simple SummaryClimate change exacerbates the threat of biological invasions by increasing climatically suitable regions for species to invade outside of their native range. Island ecosystems may be particularly sensitive to the synergistic effects of climate change and biological invasions. In Hawai’i there are 21 non-native bees that have the capacity to spread pathogens and compete for resources with native bees. We performed an ensemble of species distribution models (SDM) for eight non-native bee species (Hymenoptera: Anthophila) in Hawai’i to predict climatically suitable niches across current and future climate scenarios. We found a significant difference in habitat suitability between SDMs that were constructed with specimen records from their native and non-native (Hawai’i) range. Although SDMs predict expansion of suitable habitat into higher elevations under 2070 climate scenarios, species-rich areas are predicted to stay below 500 m elevation. Our models can inform decisions on the management of non-native bees in Hawai’i by assessing risk of invasion into new areas around the archipelago.Climate change is predicted to increase the risk of biological invasions by increasing the availability of climatically suitable regions for invasive species. Endemic species on oceanic islands are particularly sensitive to the impact of invasive species due to increased competition for shared resources and disease spread. In our study, we used an ensemble of species distribution models (SDM) to predict habitat suitability for invasive bees under current and future climate scenarios in Hawai’i. SDMs projected on the invasive range were better predicted by georeferenced records from the invasive range in comparison to invasive SDMs predicted by records from the native range. SDMs estimated that climatically suitable regions for the eight invasive bees explored in this study will expand by ~934.8% (±3.4% SE). Hotspots for the invasive bees are predicted to expand toward higher elevation regions, although suitable habitat is expected to only progress up to 500 m in elevation in 2070. Given our results, it is unlikely that invasive bees will interact directly with endemic bees found at >500 m in elevation in the future. Management and conservation plans for endemic bees may be improved by understanding how climate change may exacerbate negative interactions between invasive and endemic bee species.

Conservation management of the green carpenter bee Xylocopa aerata (Hymenoptera: Apidae) through provision of artificial nesting substrate

AbstractThe green carpenter bee, Xylocopa aerata (Smith, 1851), has undergone a severe reduction in its distribution over the previous century, in part because of habitat loss and fragmentation and its dependency on old‐growth heathland habitats. In 2007, the last remaining South Australian population, on Kangaroo Island, was negatively affected by a shortage of nesting substrate as a consequence of a series of large, intense wildfires. In an attempt to prevent yet another extirpation of this species, we developed artificial nesting substrates (stalk nests and trunk nests) and placed them at various locations within the current range of the population. Monitoring showed that the bees readily used the alternative nesting substrate in sites where very little natural substrate was left. Reproductive activity was evaluated using X‐ray images of winter nests. Based on tunnel lengths and number of individuals, we conclude that conservation action has resulted in successful reproduction and that the number of nests used has increased each year. This is the first time that provision of nesting substrate is shown to substantially improve the breeding capacity of a threatened population of endemic bees in their natural habitat. However, reproduction in artificial substrate was significantly higher in 2016 than in 2017 and 2018. The most obvious reason for the decline in breeding was climatic – low spring and summer rain in the later years limited floral resources and hence reproduction. Global climate change is causing drier conditions and more frequent and intense fires, which are reducing the likelihood of survival of this species. This effect is demonstrated by the latest fire season which left only 5% of the bees' habitat intact on Kangaroo Island. Each large‐scale fire locally annihilates bees and destroys old growth nesting substrate which takes at least 35 years to recover, thus increasing the overall risk of extinction.

Climate change and invasive species: a physiological performance comparison of invasive and endemic bees in Fiji.

Anthropogenic climate change and invasive species are two of the greatest threats to biodiversity, affecting the survival, fitness and distribution of many species around the globe. Invasive species are often expected to have broad thermal tolerance, be highly plastic, or have high adaptive potential when faced with novel environments. Tropical island ectotherms are expected to be vulnerable to climate change as they often have narrow thermal tolerance and limited plasticity. In Fiji, only one species of endemic bee, Homalictus fijiensis, is commonly found in the lowland regions, but two invasive bee species, Braunsapis puangensis and Ceratina dentipes, have recently been introduced into Fiji. These introduced species pollinate invasive plants and might compete with H. fijiensis and other native pollinators for resources. To test whether certain performance traits promote invasiveness of some species, and to determine which species are the most vulnerable to climate change, we compared the thermal tolerance, desiccation resistance, metabolic rate and seasonal performance adjustments of endemic and invasive bees in Fiji. The two invasive species tended to be more resistant to thermal and desiccation stress than H. fijiensis, while H. fijiensis had greater capacity to adjust their CTmax with season, and H. fijiensis females tended to have higher metabolic rates than B. puangensis females. These findings provide mixed support for current hypotheses for the functional basis of the success of invasive species; however, we expect the invasive bees in Fiji to be more resilient to climate change because of their increased thermal tolerance and desiccation resistance.

Filling the Egyptian pollinator knowledge-gap: checklist of flower-visiting insects in South Sinai, with new records for Egypt

Flower visitor surveys were conducted across the St Katherine Protectorate of South Sinai, Egypt, between April-July 2012 and 2013. We present a checklist of 112 species of flower visitors belonging to the orders Coleoptera, Diptera, Hemiptera, Hymenoptera and Lepidoptera. The Hymenoptera were the most diverse group of flower visitors, consisting of 69 species from eight families: Apidae (14), Colletidae (8), Crabronidae (10), Halictidae (13), Megachilidae (19), Scoliidae (1), Sphecidae (2) and Vespidae (2). We recorded nine species that were endemic to the region and thirteen that were new to the Egyptian fauna, including one new to science, Hylaeus oliviae Dathe, 2015. The study provides a valuable initial checklist of pollinators within the St Katherine Protectorate, but the description of novel species and the high proportion of new records for Egypt suggest that species numbers are likely to be underestimated. We highlight the need for future research into Egyptian pollinator fauna, particularly within the St Katherine Protectorate where endemic bees are still being described.

Bombus brasiliensis Lepeletier (Hymenoptera, Apidae) infected with Nosema ceranae (Microsporidia)

Heavy infections caused by a microsporidium were detected in midgut epithelium cells of two adult workers of the bumble bee Bombus brasiliensis Lepeletier collected near Puerto Iguazú, Misiones province, Argentina. Microsporidium rRNA (16S small subunit) was amplified by 218MITOC primers and produced amplicons indicating presence of Nosema ceranae Fries et al., a virulent pathogen of more than 20 bee species, possibly involved in Apis mellifera L. Colony Collapse Disorder. Campaigns in search of B. brasiliensis between 2008 and 2015 have revealed a possible narrower range in the southeastern area of its known distribution. Effects of N. ceranae infections could be modulating their populations and should not be overlooked. In addition, the wide host range of this microsporidium makes it a potential threat to several endemic bees such as stingless (Meliponini) and orchid bees (Euglossini).

Sugarbag Dreaming

Bees, with their ability to make sweet tasting honey, have been highly valued across many human cultures spanning thousands of years. In relation to western husbandry techniques, honeybees (Apidae) have been domesticated by humans to produce honey in large quantities for human consumption. The focus of this paper is not on the well-known, widespread honeybee but a close family relative of the Apidae, the smaller, stingless bee (Meliponidae). For Yolngu living on country, in the homeland communities of northeast Arnhem Land, Australia the relationship with these local, endemic bees is quite different from the large-scale beekeeping industry used to pollinate major agricultural crops. A highly anticipated activity is sugarbag season where Yolngu men, women and children undertake excursions into the bush in search of these tiny bees to extract honey. The bee is celebrated through “Sugarbag Dreaming”: in song, dance, painting and ceremony. This paper examines some of the ways that people and bees converge in Arnhem Land. Through the many layers of meaning, the paper aims to demonstrate how Yolngu philosophy recognises bees as being an integral part of an interconnected and complex ecology.

Revision of the "euryglossiform" species of the Afrotropical bee genus Scrapter Lepeletier & Serville, 1828 (Hymenoptera: Apoidea: Colletidae)

The South African endemic bees of the "euryglossiform" species of the genus Scrapter Lepeletier & Serville, 1828 are revised and illustrated. The species-group is defined for the first time and comprises 20 species, 16 of which are described here as new: Scrapter exiguus sp. nov. ♀, ♂, S. gessorum sp. nov. ♀, S. inexpectatus sp. nov. ♀, S. luteistigma sp. nov. ♀, ♂, S. minutissimus sp. nov. ♂, S. minutuloides sp. nov. ♀, S. minutus sp. nov. ♀, S. nanus sp. nov. ♀, ♂, S. nigerrimus sp. nov. ♀, S. nigritarsis sp. nov. ♀, S. papkuilsi sp. nov. ♀, ♂, S. punctatus sp. nov. ♀, ♂, S. pygmaeus sp. nov. ♀, S. roggeveldi sp. nov. ♀, ♂, S. spinipes sp. nov. ♀, ♂ and S. ulrikae sp. nov. ♀, ♂. For S. acanthophorus Davies, 2005 and S. sittybon Davies, 2005 the female is here described for the first time. A key to all species is provided.

Two new species of Hylaeus (Nesoprosopis) (Hymenoptera: Colletidae) from O‘ahu, Hawai‘i

New insect species, even in relatively conspicuous taxa, continue to be discovered on O‘ahu despite its status as the most intensively collected island in Hawai‘i. This paper describes two new island endemic bees, Hylaeus makaha new species and Hylaeus ulaula new species. Both are known from a single site, a patch of remnant diverse mesic forest in Makaha Valley.

Multiple mechanisms underlie displacement of solitary Hawaiian Hymenoptera by an invasive social wasp

Variation in invasion success may result from the divergent evolutionary histories of introduced species compared to those of native taxa. The vulnerability of native biotas to ecological disruption may be especially great on oceanic islands invaded by continental species with unique ecological traits. In part because Hawaii lacks native eusocial insects, social invaders may threaten endemic taxa that are ecologically similar but solitary. Using a combination of field manipulations, molecular analyses, physiological data, and behavioral assays, we identify the mechanisms underlying the displacement of two genera of native solitary Hymenoptera in Hawaii by a social continental invader, the western yellowjacket (Vespula pensylvanica). Experimental removal of V. pensylvanica colonies resulted in increased densities of native Hymenoptera. Endemic Hylaeus bees directly suffer through predation by yellowjackets, and perhaps as a consequence, avoid floral resources occupied by V. pensylvanica. Native Nesodynerus wasps also avoid V. pensylvanica but are negatively affected by yellowjackets not through predation, but through exploitative competition for caterpillar prey. Displacement of native solitary Hymenoptera may be heightened by the ability of V. pensylvanica to prey upon and scavenge honey bees and to rob their honey stores, resources unavailable to endemic bees and wasps because of their specialized niches. Our study provides a unique example of an ecologically generalized social invader that restructures native assemblages of solitary Hymenoptera by interacting with endemic taxa on multiple trophic levels.

Intra‐floral resource partitioning between endemic and invasive flower visitors: consequences for pollinator effectiveness

1. Sympatric flower visitor species often partition nectar and pollen and thus affect each other's foraging pattern. Consequently, their pollination service may also be influenced by the presence of other flower visiting species. Ants are solely interested in nectar and frequent flower visitors of some plant species but usually provide no pollination service. Obligate flower visitors such as bees depend on both nectar and pollen and are often more effective pollinators.2. In Hawaii, we studied the complex interactions between flowers of the endemic tree Metrosideros polymorpha (Myrtaceae) and both, endemic and introduced flower‐visiting insects. The former main‐pollinators of M. polymorpha were birds, which, however, became rare. We evaluated the pollinator effectiveness of endemic and invasive bees and whether it is affected by the type of resource collected and the presence of ants on flowers.3. Ants were dominant nectar‐consumers that mostly depleted the nectar of visited inflorescences. Accordingly, the visitation frequency, duration, and consequently the pollinator effectiveness of nectar‐foraging honeybees (Apis mellifera) strongly decreased on ant‐visited flowers, whereas pollen‐collecting bees remained largely unaffected by ants. Overall, endemic bees (Hylaeus spp.) were ineffective pollinators.4. The average net effect of ants on pollination of M. polymorpha was neutral, corresponding to a similar fruit set of ant‐visited and ant‐free inflorescences.5. Our results suggest that invasive social hymenopterans that often have negative impacts on the Hawaiian flora and fauna may occasionally provide neutral (ants) or even beneficial net effects (honeybees), especially in the absence of native birds.

Alien pollinator promotes invasive mutualism in an insular pollination system

The alien predatory lizard, Anolis carolinensis, has reduced the insect fauna on the two main islands of the Ogasawara archipelago in Japan. As a result of this disturbance, introduced honeybees are now the dominant visitors to flowers instead of endemic bees on these islands. On the other hand, satellite islands not invaded by alien anoles have retained the native flower visitors. The effects of pollinator change on plant reproduction were surveyed on these contrasting island groups. The total visitation rates and the number of interacting visitor groups on main islands were 63% and 30% lower than that on satellite islands, respectively. On the main islands, the honeybees preferred to visit alien flowers, whereas the dominant endemic bees on satellite islands tended to visit native flowers more frequently than alien flowers. These results suggest that alien anoles destroy the endemic pollination system and caused shift to alien mutualism. On the main islands, the natural fruit set of alien plants was significantly higher than that of native plants. In addition, the natural fruit set was positively correlated with the visitation rate of honeybees. Pollen limitation was observed in 53.3% of endemic species but only 16.7% of alien species. These data suggest that reproduction of alien plants was facilitated by the floral preference of introduced honeybees.