Hawaii is one of the most remote archipelagos in the world. This remoteness has fostered a unique flora and fauna. Bees have been no exception. Only one type of bee has managed to enter Hawaii and spread here as a native type. It is a yellow-faced bee, Hylaeus.
Classification of yellow-faced bees
Hawaiian bees belong to the family Colletidae, Subfamily Hylaeinae, Genus Hylaeus. There are 500 species in total. Present on all continents except Antarctica. Very common in Hawaii.
Yellow-faced bee expansion in Hawaii
Once in Hawaii, the yellow-faced bee evolved to form 63 native species. That’s 10% of all yellow-faced bee species worldwide. This is even more than the number of species in North America, where the bee spread from.
The yellow-faced bee in Hawaii has not faced competition with other bees for habitat. Therefore, this ubiquitous bee has spread throughout the islands from the most humid to the most arid forests, from the coast near the sea to the high alpine desert near 10,000 feet on Mauna Kea and Haleakalā, where they visit silversword flowers.
The importance of Hawaiian bees for plant pollination
Over time, Hawaiian bees have adapted to the local flora. They play a major role in pollinating native plants: ‘ōhi’a lehua (Metrosideros polymorpha) and ‘ōlapa (Cheirodendron spp.) in wet forests; māmane (Sophora chrysophylla), naio (Myoporum sandwicense), ‘akoko (Chamaesyce spp.) in wet forests; and ‘ōlapa (Cheirodendron spp.) in wet forests. ), ‘a’ali’i (Dodonaea sandwicensis), and pūkiawe (Leptecophylla tameiameiae) in dry forests and shrublands; silverswords and their relatives (Argyroxiphium and Dubautia spp. ) and nohoanu (Geranium spp.) in subalpine areas; and naupaka (Scaevola taccada), ‘ohai (Sesbania tomentosa), pā’ū o Hi’iaka (Jacquemontia ovalifolia), and ‘ilima (Sida fallax) at the coast.
Honeybees, introduced from the continent in 1857, also visit these plants. But they are often worse pollinators because they have longer proboscis with which they easily take the nectar and quickly leave the plant without paying attention to pollination.
Hawaii’s ecosystem change
The ecosystem of the Hawaiian Islands evolved without humans for a long time. Changes began to occur when Polynesians arrived 800 years ago. And in the late 18th century, Europeans arrived. Since then, the pressure on local wildlife has increased many times over.
Non-native animals and plants began to appear in Hawaii and displace native ones.
The rats, followed by cattle, goats, pigs and sheep, radically changed the vegetation. They transformed the forests into grasslands and prevented the reproduction of some of the most important native plants. Ants also have a devastating direct effect on bees. In particular, the long-legged or yellow crazy ant (Anoplolepis gracilipes) and the Argentine ant (Linepithema humile) exclude bees both by direct predation and by feeding on nectar.
The extinction of Hawaiian bees
Today it is very difficult to find Hawaiian bees. To do so, you need to look for them in places where native vegetation is preserved in the mountains or on certain parts of the coast. It is almost impossible to see them in places where people live.
7 species of Hawaiian Hylaeus are almost extinct. 9 other species have not been seen for 80 years. Other species that used to be rarely seen in certain places are now impossible to find.
Argentine ants are spreading more and more throughout the islands, displacing native bees.
More recently, a new species of yellow-faced bee, Hylaeus strenuus, has been spotted in Hawaii. It was previously known from the territory of India. It is believed that it could become a serious competitor for local bees.
As a result of poor control of plant imports to the islands, more and more imported species will emerge to compete with and displace native bees.
Efforts to conserve Hawaiian bees
On 30 September 2016, US federal authorities placed seven species of bees in the genus Hylaeus, known as Hawaiian yellow-faced bees, on the list of endangered species protected by law.
After years of research by the non-profit conservation organisation Xerces Society, the US Fish and Wildlife Service (USFWS) has listed seven bee species endemic to Hawaii – Hylaeus anthracinus, Hylaeus longiceps, Hylaeus assimulans, Hylaeus facilis, Hylaeus hilaris, Hylaeus kuakea and Hylaeus mana – as threatened with extinction.
Conclusion
Research shows that native bees periodically appear in new places, where they have not been seen before.
But despite these pressures and the uncertain future of native pollinators, they continue to resist external threats and show adaptability and persistence to survive.
