Long lost monitor lizard 're-discovered' on Papua New Guinean island

Date: May 2, 2017

Source: University of Turku

Scientists have recently found and re-described a monitor lizard species from the island of New Ireland in northern Papua New Guinea. It is the only large-growing animal endemic to the island that has survived until modern times. The lizard, Varanus douarrha, was already discovered in the early 19th century, but the type specimen never reached the museum where it was destined as it appears to have been lost in a shipwreck.

(Credit: Valter Weijola)

The discovery is particularly interesting as most of the endemic species to New Ireland disappeared thousands of years ago as humans colonized the island.

The monitor was discovered during fieldwork by Valter Weijola from the Biodiversity Unit of the University of Turku, Finland, who spent several months surveying the monitor lizards of the Bismarck Islands. It can grow to over 1.3 metres in length and, according to current information, it is the only surviving large species endemic to the island. Based on bone discoveries, scientists now know that at least a large rat species and several flightless birds have lived in the area.

"In that way it can be considered a relic of the historically richer fauna that inhabited the Pacific islands. These medium-sized Pacific monitors are clearly much better at co-existing with humans than many of the birds and mammals have been," says Weijola.

 

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Neonicotinoid pesticide reduces egg development in wild bumblebee queens

May 3, 2017

New research published in the journal Proceedings of the Royal Society B has found that wild bumblebee queens are less able to develop their ovaries when exposed to a common neonicotinoid pesticide

The research was conducted by Dr Gemma Baron , Professor Mark Brown of Royal Holloway, University of London and Professor Nigel Raine, (now based at the University of Guelph).

The study investigated the impact of exposure to field-realistic levels of a neonicotinoid insecticide (thiamethoxam) on the feeding behaviour and ovary development of four species of bumblebee queen.

Reduced ovary development across bee species

Lead author, Dr Baron said, "We consistently found that neonicotinoid exposure, at levels mimicking exposure that queens could experience in agricultural landscapes, resulted in reduced ovary development in queens of all four species we tested."

She continued, "Impacts of neonicotinoid exposure on feeding behaviour were species-specific, with two out of four species eating less artificial nectar when exposed to the pesticide. These impacts are likely to reduce the success of bumblebee queens in the spring, with knock-on effects for bee populations later in the year" added Baron.

As the first to examine the impacts of these chemicals across multiple bumblebee species, this study is an important contribution to understanding the potential costs of using this class of insecticides.

Dr Baron explained, "Previous studies have focused on a single bumblebee species and examined impacts in workers and established colonies. Bumblebee populations rely on spring queens to succeed, and by looking at the impacts of thiamethoxam on multiple species of spring queens, we have gained a step-change in our understanding".

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35-year South Carolina alligator study uncovers mysteries about growth and reproduction

May 3, 2017 by Jonathan Veit

Research by wildlife biologists from Clemson University and the Tom Yawkey Wildlife Center near Georgetown is shattering conventional scientific understanding about American alligator growth and reproduction.

For years, it was believed that American alligators continued growing in length until they died, what is called "indeterminate growth." But a 35-year study of a protected alligator population at the Yawkey Center on the South Carolina coast has found that male and female alligators exhibit "determinate growth." In other words, they stop growing at some point after they reach sexual maturity.

Additionally, females are reproductive far longer than previously thought, 46 years past the onset of sexual maturity in one case, the study found.

The study was performed by retired Yawkey Center manager and South Carolina Department of Natural Resources wildlife biologist Phil Wilkinson, Clemson University Baruch Institute of Coastal Ecology and Forest Science wildlife biologist Thomas Rainwater and three colleagues with the Florida Fish and Wildlife Conservation Commission. The team published its findings in Copeia, the journal of the American Society of Ichthyologists and Herpetologists.

Wilkinson, whom Rainwater calls, "one of the grandfathers of South Carolina alligator research," began examining the Yawkey alligators with names like Truck Biter, Big Bertha, Cudjo, Grover and Bette Davis Eyes in 1979 as part of a population and nesting ecology study, making the Yawkey alligator study the longest known continuous alligator study in the world.

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Meerkat call patterns are linked to sex, social status and reproductive season

May 3, 2017

 

Within a group of meerkats, call patterns vary with factors including sex, rank and reproductive season—but not with stress hormones, according to a study published May 3, 2017 in the open-access journal PLOS ONE by Jelena Mausbach from University of Zurich, Switzerland; Marta Manser from University of Pretoria, South Africa; and colleagues.

Meerkats live in family groups with social hierarchies, emitting contact calls that help maintain group cohesion during foraging. These calls are distinctive and have variable rates across individuals, but the influences on this behavior are unknown. To identify factors linked to call patterns, Mausbach, Manser and colleagues analyzed sound recordings and measured fecal stress hormones of 64 meerkats from 9 groups in the wild.

The researchers found that call patterns vary with factors such as sex, social status, and reproductive season, suggesting that meerkat calls within a family group provide listeners with cues about the producers.

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Fish step up to lead when predators are near

May 3, 2017

Researchers from the University of Bristol have discovered that some fish within a shoal take on the responsibilities of leader when they are under threat from predators.

The findings, reported today in Science Advances and funded by the UK's Natural Environment Research Council, suggest that the majority of decisions made by the leader fish are followed, making the shoals more effective.

And it was the shoals where fish had defined leader/follower roles that were more evident in areas where predators were more prevalent. Dr Christos Ioannou from the university's School of Biological Sciences, said: "There are many benefits of group living, and making decisions together can dramatically increase the survival of many species - this is why many birds flock and fish shoal.

"Groups can be guided by leaders, where a single individual makes most of the decisions, or egalitarian, where everyone contributes.

Dr Christos Ioannou and colleagues found that guppies from areas with high predation differentiate more into either leaders or followers. This is the first evidence that predators may influence how individuals contribute to decisions in groups.

Behaviour of over 300 fish from rivers with varying predation risk was studied.

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