Birds and bee lessons as Pacific field trips also solve 'Michener's mystery'

FLINDERS UNIVERSITY

Fiji highlands — IMAGE:
LAKE TAGIMOUCIA AS SEEN FROM DES VOEUX PEAK ON TAVEUNI, FIJI. BOTH THE LAKE AND THE PEAK HAVE BEEN THE SITES WHERE NEW SPECIES WERE FOUND. THE PEAK IN PARTICULAR IS WHERE THE FIRST FIJIAN HYLAEUS WERE COLLECTED FOR THIS PROJECT.
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CREDIT: COURTESY AMES DOREY PHOTOGRAPHY

Eight new Pacific bee species and new insights into Fijian bird behaviour on Viti Levu Island have been described in new scientific studies led by Flinders University.

The studies, both funded by field work supported by the Australian Government’s New Colombo Mobility Plan Program, highlight the potential for species discovery, ecological and conservation knowledge and cultural engagement from Asia-Pacific research collaborations.

In the past 10 years, Australian Government-funded Flinders University field trips have worked closely with the University of the South Pacific, government agencies and other researchers to support important ecology and conservation work in Fiji.

Flinders PhDs Dr James Dorey and Dr Ben Parslow joined researchers from Fiji, Hawaii and Australia to study a totally new group of bees in forest canopies.

“Our investigations have discovered an extra group of endemic bees in Fiji that have remained ‘hidden’ in the forest canopy despite years of looking and sampling,” says Australian native bee expert Dr Dorey, now a lecturer at the University of Wollongong.

“Through our local collaborations, we also know that these bees are widespread in the Pacific.

“Happily, this also solves ‘Michener’s mystery’ about how these tiny (3-5mm) Hylaeus made it to French Polynesia, dispersing over time from their closest relatives which were 4000km north in Hawaii and 6000km west in Australia.”

Six Fijian species found foraging in trees are only the second native genus on the archipelago. One was found in French Polynesia (“more than 3000km as the bee flies”) and one in Micronesia – further highlighting their value of forests to pollinators – and the potential for many more species to be found across the Pacific.

“Unlike the super-generalist Homalictus bees that inhabit Fiji and likely benefitted from ancient human-clearing, the Fijian Hylaeus are likely very vulnerable to anthropogenic clearing and may be critical pollinators in forest habitats,” says Dr Dorey.

Co-author Dr Parslow, South Australian Museum taxonomist, says the study emphasises the benefits of long records of sampling in understanding diversity and conservation measures required for bee and other pollinators – particularly for land and environmental managers.

The study references the pioneering work of US entomologist Charles Michener who wrote the seminal work Bees of the World in 2007, including studies on the social evolution of the Halictidae bee family in the 1960s.

In another study, Flinders University and University of South Australia (UniSA) researchers worked with University of the South Pacific (USP) researchers to understand more about native forest birds in Fiji.

USP Dr Alivereti Naikatini, with Flinders Professor Sonia Kleindorfer (now University of Vienna) and UniSA Associate Professor Gunnar Keppel, have recently published on the insect foraging and territorial defence of Fiji’s forest birds – focusing on the impacts of human disturbance and other threats to their survival.

Common bird species silvereye, Fiji white-eye, Vanikoro flycatcher and the Slaty monarch were studied in community-managed national parks on Viti Levu Island were studied over three years, from 2017 and 2019.

This kind of information can be useful to plan habitat refuge and protection under conditions of climate change or further human activity, says Flinders Professor Kleindorfer.

Read more in ‘Elevational differences in territory defence response in native (endemic and non-endemic) forest birds on Viti Levu Island, Fiji’ (2023) by Alivereti N Naikatini, Gunnar Keppel, Gilianne Brodie and Sonia Kleindorfer in the New Zealand Journal of Zoology. DOI: 10.1080/03014223.2023.2268533 https://doi.org/10.1080/03014223.2023.2268533

and

‘Canopy specialist Hylaeus bees highlight sampling biases and resolve Michener’s mystery’ (2024) by James B Dorey, Olivia K Davies, Karl N Magnacca, Michael P Schwarz, Amy-Marie Gilpin, Thibault Ramage, Marika Tuiwawa, Scott VC Groom, Mark I Stevens and Ben A Parslow just published in Frontiers in Ecology and Evolution DOI: 10.3389/fevo.2024.1339446 (available when embargo lifts).

James Dorey Photography images and captions at the link

JOURNAL

Frontiers in Ecology and Evolution

DOI

10.3389/fevo.2024.1339446

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

‘Canopy specialist Hylaeus bees highlight sampling biases and resolve Michener’s mystery’

ARTICLE PUBLICATION DATE

26-Feb-2024

How did a tiny bee get to French Polynesia? Eight new species help solve a scientific mystery

Scientists discover a previously unknown species radiation of masked bees, restricted to the tree canopies of Pacific islands

Peer-Reviewed Publication

FRONTIERS

Hylaeus derectus — IMAGE:
HYLAEUS DERECTUS MALE. THIS LITTLE BEE (3–5 MM) BEE IS ONLY KNOWN THUS FAR FROM NEAR MT NADARIVATU ON VITI LEVU, FIJI. IT WAS COLLECTED FROM A CANOPY-FLOWERING MISTLETOE.
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CREDIT: JAMES DOREY PHOTOGRAPHY

In 1934, American entomologist Elwood Zimmerman, then an undergraduate student at Berkeley, participated in the ‘Mangarevan expedition’ to Polynesia. Among the samples he collected were three tiny (4 mm long), orange-brown solitary bees found on tahetahe flowers in the Tuamotu Archipelago.

The specimens rested undisturbed in the Bernice P Bishop Museum of Honolulu until 1965, when the famous bee specialist Prof Charles Michener examined them. He described them as a species new to science: Hylaeus tuamotuensis, or Tuamotu’s masked bee, in the family Colletidae.

How these tiny bees had reached French Polynesia was a mystery: its nearest known relatives lived in Australia, New Guinea, and New Zealand, more than 3,000 km west of Tuamotu. What’s more, the new species had never been collected again and was feared extinct – until the present day.

Now, 59 years later, the puzzle has been answered in a new study published in Frontiers in Ecology and Evolution.

“Here we show that, despite almost a decade of sampling for bees in Fiji, there is a whole group of species that flew right over our heads until now. By exploring new sampling techniques, we discovered an unknown species radiation of Hylaeus masked bees in the forest canopy,” said Dr James Dorey, a lecturer at the University of Wollongong and an adjunct lecturer at Flinders University and lead author of the study.

“With these bees we can solve the mystery: the ancestors of H. tuamotuensis reached French Polynesia by island-hopping via Fiji and the southwest Pacific!”

New to science

There, the team of authors describe eight new species of Hylaeus, discovered between 2014 and 2019 in the Pacific and shown by DNA barcoding and morphology to be relatives of Tuamotu’s masked bee – no longer an anomaly.

Six of the newly discovered species are from the Fijian archipelago: named the straight-faced, little yellow-spotted, and Navai’s Hylaeus from the island of Viti Levu, and the white-spotted, open-faced, and veli’s Hylaeus from Taveuni. Chuuk’s Hylaeus was discovered on Chuuk in the Federated States of Micronesia, and the golden-green Hylaeus on Tahiti in French Polynesia, 450 km southwest of Tuamotu.

The team were only able to discover the new species by sampling from the tree canopy on these islands. Previous sampling efforts had focused on flowering plants at ground level, which the new species seem to avoid. Also surprising was that that the new species seem to prefer red flowers, as the sensitivity of most bees to red light is poor.

“It wasn’t until we brought very long nets to Fiji and started collecting from the trees that we started to find our mysterious little bees. Maybe we should not be surprised when the etymology of Hylaeus might mean ‘belonging to the forest’,” said Dorey.

More discoveries expected soon

Hundreds of islands lie between Fiji and French Polynesia, for example Tonga, Samoa, the Cook Islands, and Wallis and Futuna. Now that the scientists know to look for them in the canopy, they expect to discover many more Hylaeus species on those islands.

But how did the bees hop between islands? Their typical flight range is unknown, but likely only a few kilometers.

“Because most masked bees nest in wood, it’s likely that they rafted between islands, especially when tropical cyclones wash masses of plant materials down rivers and out to sea. It is also possible that they were blown by high winds, but that would have been a much more perilous journey for our little bees,” said Dorey.

Guardians of the forests

How long ago these dispersal events happened can’t be resolved yet from the available DNA data. Nor do the authors know how common the new species are on the islands to which they appear to be endemic.

“[We named veli’s Hylaeus] for the veli of Fijian folklore who are powerful little people associated with forests. Accounts of the veli are varied and they were often seen in a positive light, but they could also be dangerous, for example, if you chopped down their favorite trees. Hence, the name is meant to invoke a sense of responsibility for protecting these new forest-specialist species and their trees,” reminded the authors.

Hylaeus navai female. Found on the Viti Levu and Taveuni islands of Fiji, this species is still only known from the females, but is named in honour of Navai Village and their long-term support of Fijian bee research

Navai Village on the island of Viti Levu, Fiji. Including locals, guides, hosts, and Flinders University/University of South Australia students that were funded by the Government’s New Colombo Plan in 2019.

Much of our research would be impossible without the help of locals who act as guides, hosts, and friends. Here, guides and researchers pause for a break while hiking up to Lake Tagimoucia in tropical heat.

Mount Tomanivi is Fiji’s highest peak at 1,324 m above sea level. It is home to unique bee species, although it has yet to be specifically sampled for new Hylaeus bees.

Namosi Village on Viti Levu Island, Fiji, shows an incredible mixture of anthropogenic and forested habitats with a backdrop of wild mountains.

Lake Tagimoucia as seen from Des Voeux Peak on Taveuni, Fiji. Both the lake and the peak have been the sites where new species were found. The Peak in particular is where the first Fijian Hylaeus were collected for this project.
CREDIT
James Dorey Photography