Flying Fox Corridors | ‘Extinct’ Trees Found | Butterfly Disguise | Treasure Box
‘Forest Corridors’ Needed to Link Flying Fox Colonies
The Livingstone’s flying fox – a critically-endangered fruit bat – is in danger of becoming inbred because of its inability to cover even small distances between separate colonies that have been isolated by deforestation on the Indian Ocean’s Comoros archipelago.
Livingstone’s flying foxes typically only forage around three kilometres (1.8 miles) from their roosts, researchers say. The bats are certainly unable to cross the 40 kilometres (24 miles) of ocean that separates the two Comoran islands they occupy: Mohéli and Anjouan.
This inability to island hop means that it is vital for bat colonies on each island to remain connected to each other via unbroken tracts of forest. Yet, on Anjouan, tree felling to make way for crops has led to forest fragmentation. The island’s bat colonies in the north and the south have become increasingly isolated.
Researchers from the Group for Research and Protection of the Fauna and Flora of the Indian Ocean Islands studied eight bat colonies on Anjouan and discovered that limited gene flow is occurring between them.
Even colonies just six kilometres (3.7 miles) apart on the north of the island were becoming genetically different from each other, meaning deforestation is preventing cross-breeding between relatively nearby colonies.
“If fragmentation continues to increase in these regions, this could impact all individuals and prevent gene flow for all subpopulations,” the researchers warn.
They recommend that conservation groups on the island work to create corridors of forest to reconnect bat habitats to ensure this critically-endangered species – the archipelago’s most iconic mammal – doesn’t go extinct.
Livingstone’s flying foxes in the Comoros | Charlène Selva | Wikimedia Commons
'Extinct' Trees Found in Tanzania, Seedlings Propagated
Two rainforest trees of a species feared to be extinct have been found growing in cultivated fields in eastern Tanzania and thousands of their seeds have been collected and germinated so that they can be planted as part of a reforestation project.
Millettia sacleuxii trees are so rare they have no common name.
Years previously scientists knew the species from just six individual trees in three forest reserves in the Nguru and Usambara Mountains in eastern Tanzania. But two of the reserves have been cleared and replaced with exotic timber and sugar plantations and the remaining reserve has been reduced to around 123 acres (49 hectares) surrounded by encroaching fields of sugar.
“I was really worried about this species and fearing it may have gone extinct,” Andrea Bianchi, a tropical forest restoration expert who positively identified the two surviving trees, told me.
The two single evergreens were found near the Nguru Mountains and had somehow survived being cut down for poles or firewood, or to make way for crops like the rest of the rainforest that once surrounded them.
To the delight of Bianchi and colleagues from conservation group, the PAMS Foundation, the trees were also heavily laden with pods.
Once the seeds were shed, around 7,000 were collected and taken to a tree nursery the foundation runs in Nguru. Of these, 5,500 germinated and will be planted in an area where the conservation group is working with villagers to regrow parts of the rainforest.
The Nguru massif is one in a chain of 12 similar mountain blocks known for their rich plant and animal diversity, but which have also lost more than 70 per cent of their forest cover over the last century.
Nguru Mountains, at a spot near to where the two Millettia trees were found | Ryan Truscott
Female Diadem Butterflies Repurposed Ancestral Wing Patterns to Dodge Birds
Scientists can now explain how female Diadem butterflies repurposed an ancestral wing pattern to look like toxic African Queen butterflies to avoid predators.
So complex is the mimicry that female Diadems in different regions of Africa even mimic the different forms of the African Queen that occur there.
The team behind the discovery used complex gene sequencing to work out that female Diadems – which are edible to predators like birds – adopted the orange and white wings of their ancestors in order to mimic African Queens, which birds avoid.
Under the phenomenon known to science as Batesian mimicry the females forfeited the striking black wings with white spots that are typical Diadem features still retained by the males.
Males forego the protective disguise because it's more important for them to look like Diadems to attract females, the researchers say.
“The males and females look like totally different butterflies, even though they share the same genome,” Dino Martins, a co-author of the paper, said in a statement.
Until now it was not known how the Diadem females adopted the look of the poisonous African Queens, also known as African Monarchs, whose caterpillars forage on milkweed plants like their North American cousins.
The team compared the DNA of more than 300 female Diadems to four other closely-related species that were found to not possess the genes that give rise to the orange wing patterns.
This, the researchers say, suggests the mimicry is a rare case of “adaptive atavism”, which refers to when a species reverts to a state found in its ancestors.
African Queens (top of each pair) and female Diadems (bottom of each pair | University of Exeter
Nature Notes: Finding Treasure
Below is a picture of our 12-year old’s treasure box. She collected them at the Mazowe Botanical Reserve, north of Harare, while we were busy identifying and labelling trees to promote the public understanding of the richness of Zimbabwe’s miombo woodlands.
There was the light green duiker-berry from the tree with the longest scientific name in the book; the papery winged seeds of the velvet bushwillow, and the bright red fruit of Corallocarpus wildii, whose green apex opens to eject a seed like a granadilla pip.
Someone asked me how I managed to instill a love of plants and nature in our daughter’s heart.
When she was a baby, I explained, I would put her in a borrowed blue canvas backpack carrier and hike with her up into the woodlands behind our house in eastern Zimbabwe.
To stop her getting restless on the return journey, I’d pick her a leaf or a pod off a tree or a shrub. It was a different one each time. She’d twiddle it between her fingers the whole way home without a murmur.
They were treasures that captivated her back then, and still do.
