Lost Chimpanzee Traditions | Feathered Guides, Sweet Gains | Beetlemania | Predatory Pond Plant
Chimpanzees Forget Mating Signals as Males Die Out
Male chimpanzees in four separate groups living in Ivory Coast's Taï National Park use different "auditory gestures" to attract females, according to a group of researchers.
These vary from tapping their heels or knuckles against hard surfaces, shaking branches or clipping leaves off stems. But if the males die out, so does the social norm.
In one of the groups in the north of the park, where the knuckle-knock was the sole solicitation gesture used since 1991, all the adult males were killed by poachers by 2008.
It meant that for the next eight years, no two adult males were together in the group using the knuckle-knock to compete with each other for mates.
Though male numbers in the group have now returned to what they were before, the knuckle-knock has not reemerged. Instead, it's been replaced by the heel-kick.
"Our evidence highlights the urgent need to integrate chimpanzee cultural preservation with conservation," the authors write in Current Biology.
Intriguingly the research also highlights how male chimps on the other side of the continent, in Uganda's Budongo Central Forest Reserve, use their own repertoire of signals while sharing some of those used in Taï, albeit with slightly different meanings.
A leaf-clip in Budongo, for instance, is a "primary copulation solicitation signal" while in Taï it’s mostly used in playful contexts.
Birds Boost Incomes for Mozambique's Honey-Hunters
Three quarters of the honey harvested by communities living in Mozambique’s largest wildlife reserve is gathered with the help of wild honeyguide birds.
All 47 villages in the Niassa Special Reserve used the services of the birds, says a new study, published in the journal Ecosystem Services.
Poverty and unemployment in Niassa are high. Most people earn less than $2 per day. So, the modest economic gains reaped by hundreds of honey-hunters does make a significant difference to people’s economic well-being, says lead researcher Jessica van der Wal.
The research team estimated that around 500 honey-hunters earned more than $40,000 in 2023 with the help of honeyguides, which are slender brown birds with shrill calls.
The focus of the study was on those who find honey and sell it, but honey-hunting is also done opportunistically by many others from the three ethnic groups living in Niassa.
The conditions in Niassa are unique to preserving this human-bird partnership. It is a remote reserve, meaning people don’t have access to honey substitutes like cane sugar, and the miombo woodlands are intact and full of wild bees’ nests.
They’re also densely-populated with honeyguides. There are estimated to be more than 16 honeyguides per 100 hectares (247 acres).
This means there’s always a bird keen to lead a hunt in return for a reward of beeswax left for it by the honey-hunters who possess the hands and the tools that can open up wild bees’ nests — something the honeyguides can’t do on their own.
Goliath Beetles in Peril
Populations of supersized beetles, known as Goliath beetles, have declined by up to 80% in the wild, a new study says, and collectors are partly to blame.
Three out of four species of Goliath beetles surveyed across their range in West, Central and East Africa from 1994-2024 are either critically-endangered, endangered or near-threatened with extinction.
Goliath beetles grow up to 10 centimetres (3.9 inches) long; they’re big enough to sit snugly in the palm of your hand. Their bodies are iridescent white with bold black markings. Some have deep brown wing covers.
But these good looks are a liability.
Over the past 20 years one species, Goliathus cacicus, has declined by more than 80% across its West African range, which extends from Guinea to Ghana, the study says.
The species is confined to rainforests and was exported by the thousands from Ivory Coast in the 1980s and 1990s.
Habitat loss has also played a big part in driving them towards extinction. For example, the replacement of rainforests and agro-forestry plots with extensive cocoa plantations in south-western Ivory Coast “has decimated and likely extirpated several populations of G. cacicus,” the authors say.
They recommend certifying specific forests for beetle conservation and enforcing sustainable harvesting practices (only collecting the males means females are left to lay their eggs and ensure viable wild populations persist).
In Cameroon, a number of communities depend on harvesting the near-threatened Goliathus goliatus (pictured below) as a key source of income.
Sustainable trade could help Goliath beetles to survive, people to prosper and the forests they share to remain standing.
Encounter with a Predatory Pond Plant
It’s not every day that you get to see a carnivorous plant — especially one so tiny it would be easily overlooked if you weren’t in the company of a sharp-eyed botanist.
The plant I saw on Pemba Island, off the coast of Tanzania, was a species of bladderwort, or Utricularia.
It was floating on a freshwater pond in the middle of heathland in the north of the island when I visited in early December together with botanists and conservationists.
One of the botanists waded waist-deep into the pond to collect one of the Utricularia plants, which was small enough to fit between his forefinger and thumb.
He showed me how the plant has a small trap to capture and digest tiny insects and aquatic animals from water that is otherwise devoid of nutrients.
But while the plant eats some invertebrates, it rewards others. The flowers — held aloft like tiny white flags — feed nectar to flying insects in return for pollination.
The heathland is a fascinating place to be in. It is dominated by Erica shrubs that grow up to 10 metres (32 feet) in height. Their springy twigs covered with miniscule leaves resemble vivid green pipe cleaners.
But cattle farmers who enter the reserve from surrounding villages sometimes burn the heathland to create fresh grazing. If this happens too frequently the Erica shrubs become stunted, the margins of the surrounding forest advance and the heathland and its fascinating residents, like the hungry bladderworts, could be lost.
