Un nid de guêpes inversé avec une entrée secrète
In a fascinating discovery published in the Journal of Hymenoptera Research, a new species of black and green social wasp from Madagascar, named Ropalidia jemmae, challenges the conventional design manual of its genus. Unlike the typical round and three-dimensional nests found in other Ropalidia species, the nest of Ropalidia jemmae displays a unique "upside-down" design. When approached, the nest appears as a flat piece of grey-green lichen attached to a tree, with the entrance of each cell facing the tree trunk and the "floor" of the cells, pointing towards the sky, forming a flat "roof" under which up to 30 adult wasps hide.
This inverted nest structure, a rarity outside the Americas, requires more construction materials, time, and effort compared to the more efficient, geometrically aligned nests. Ropalidia jemmae cleverly utilizes lichen to build and conceal its nest from potential threats such as ants, beetles, other wasps, and birds. The flat roof of its nest, leaning against a tree, adds an extra layer of camouflage.
The green markings on the mostly black body of Ropalidia jemmae, coupled with its small size of 1.5 centimeters, further enhance its camouflage against predators. These green elements suggest that visual predation plays a significant evolutionary role for this species, unlike the bright yellow and black colors of social wasps in temperate regions. While some Malagasy species of social wasps can have over 500 adults in mature nests, Ropalidia jemmae colonies house only around thirty adults.
The species is named after Jemma, the daughter of Len de Beer, who participated in the search for additional wasp specimens. Madagascar, often referred to as one of the world's "last Edens," boasts an exceptional level of biodiversity, with over 80% of its species found nowhere else on Earth. The island harbors more unique species than any other landmass of comparable size, making it a hotspot for new species discoveries, especially among terrestrial invertebrates.
The forests of Ambohitantely and Ankafobe, where Ropalidia jemmae was found, are described as "tiny jewels of fragmented biodiversity" by Len de Beer. These forests are home to a multitude of irreplaceable endemic species, many of which remain undiscovered. Proper conservation efforts are crucial to protect these forests in Madagascar, as failure to do so could rapidly escalate the recently discovered wasp species from an undescribed status to a threatened one.
Ozren Polašek, the lead author of the study, has also documented another new species of Ropalidia, Ropalidia amabala, in South Africa's Eastern Cape province. This species represents the first known member of the genus outside Madagascar to utilize lichen to build its nest directly on a tree trunk. Named after the Zulu word "amabala" meaning "spots," Ropalidia amabala features six characteristic spots on its dark brown abdomen, aiding in its environmental camouflage.
From an evolutionary perspective, Ropalidia amabala does not appear closely related to Malagasy Ropalidia species. This suggests that the visual concealment of nests within this genus has evolved independently twice, once in Madagascar and once in South Africa, as explained by Polašek.
The discoveries of Ropalidia jemmae and Ropalidia amabala highlight the importance of preserving diverse ecosystems in Madagascar and South Africa to safeguard unique and undiscovered species. These findings underscore the need for continued research and conservation efforts to protect the rich biodiversity of these regions and prevent the rapid endangerment of newly identified species.
Source: https://www.nature.com/articles/d44148-024-00079-w
This inverted nest structure, a rarity outside the Americas, requires more construction materials, time, and effort compared to the more efficient, geometrically aligned nests. Ropalidia jemmae cleverly utilizes lichen to build and conceal its nest from potential threats such as ants, beetles, other wasps, and birds. The flat roof of its nest, leaning against a tree, adds an extra layer of camouflage.
The green markings on the mostly black body of Ropalidia jemmae, coupled with its small size of 1.5 centimeters, further enhance its camouflage against predators. These green elements suggest that visual predation plays a significant evolutionary role for this species, unlike the bright yellow and black colors of social wasps in temperate regions. While some Malagasy species of social wasps can have over 500 adults in mature nests, Ropalidia jemmae colonies house only around thirty adults.
The species is named after Jemma, the daughter of Len de Beer, who participated in the search for additional wasp specimens. Madagascar, often referred to as one of the world's "last Edens," boasts an exceptional level of biodiversity, with over 80% of its species found nowhere else on Earth. The island harbors more unique species than any other landmass of comparable size, making it a hotspot for new species discoveries, especially among terrestrial invertebrates.
The forests of Ambohitantely and Ankafobe, where Ropalidia jemmae was found, are described as "tiny jewels of fragmented biodiversity" by Len de Beer. These forests are home to a multitude of irreplaceable endemic species, many of which remain undiscovered. Proper conservation efforts are crucial to protect these forests in Madagascar, as failure to do so could rapidly escalate the recently discovered wasp species from an undescribed status to a threatened one.
Ozren Polašek, the lead author of the study, has also documented another new species of Ropalidia, Ropalidia amabala, in South Africa's Eastern Cape province. This species represents the first known member of the genus outside Madagascar to utilize lichen to build its nest directly on a tree trunk. Named after the Zulu word "amabala" meaning "spots," Ropalidia amabala features six characteristic spots on its dark brown abdomen, aiding in its environmental camouflage.
From an evolutionary perspective, Ropalidia amabala does not appear closely related to Malagasy Ropalidia species. This suggests that the visual concealment of nests within this genus has evolved independently twice, once in Madagascar and once in South Africa, as explained by Polašek.
The discoveries of Ropalidia jemmae and Ropalidia amabala highlight the importance of preserving diverse ecosystems in Madagascar and South Africa to safeguard unique and undiscovered species. These findings underscore the need for continued research and conservation efforts to protect the rich biodiversity of these regions and prevent the rapid endangerment of newly identified species.
Source: https://www.nature.com/articles/d44148-024-00079-w
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