Bees are nearly lost before they’re found

Australian researchers have named nine new species of bees from the genus Homalictus Cockerell in the Fijian archipelago, the first time these jewel-coloured pollinators have been formally reviewed for 40 years.

That’s the good news. Not so encouraging is the finding that at least one group may be extinct, and the others are showing signs of sensitivity to global warming.

Previously, four species were discovered in the tropical region, prompting James Dorey, photographer and researcher from Flinders University in Adelaide, Australia, and colleagues to investigate further.

Dorey says they’ve found around 23 new species in Fiji alone, and discover new ones every year when they revisit the region. The present study, published in the journal Zootaxa, describes the specimens for which they have both sexes.

Telling the Fijian bees apart is no easy feat, because most of them appear very similar. To work around this, the researchers used DNA barcoding and confirmed the results by examining physical characteristics such as male genitalia. 

“You could say that there really is just a bee’s dick difference between some species,” says Dorey. 

One of the previously discovered species, Homalictus achrostus – perhaps one of the most morphologically unique – has only ever been found on one mountain top, Nadarivatu.

Six specimens of this group were collected in 1978 and two in 2010 by the researchers’ colleague Scott Groom, but the bee foragers have not been able to find any since then despite searching thoroughly every year. Dorey is concerned they have become extinct as these species appear to be sensitive to warm temperatures.

In fact, most of the Fijian bees have only been found on single mountain tops, over 800 metres above sea level. This is significant because the highland-restricted pollinators appear to be seeking the cooler temperatures at higher altitudes. 

They even named one H. terminalis to highlight that it’s nearly at its limit. The team could only find these bees near the very peak – within 95 metres – of Mount Batilamu near the city of Nadi, a popular tourist location.

“For island taxa that cannot disperse latitudinally,” Dorey explains, “the only place they can go is up – assuming there is somewhere higher for them to go. If things warm up enough, their climatic niche could be pushed off the top of the mountain, and that species should go extinct.”

Binomials for the nine new species include H. groomi and H. tuiwawae, named after Groom and the team’s Fijian collaborator, Marika Tuiwawa from the University of the South Pacific, respectively.

They hope to name the remaining specimens next, even if they only have one sex. Despite the tropics being a biodiversity hotspot for many bees, it has been poorly studied until now, Dorey says, and this could have broader ramifications.

“Our paper highlights that bee diversity in Fiji has been grossly underestimated and that much of this diversity is at risk of extinction. If the same is true across the tropics, then we stand to lose many species before we have even discovered them.”