Plants and Animals

Photographing this roosting pair of Wompoo Fruit-Doves Ptilinopus magnificus was simply irresistible. Over the years, I have seen many asleep, but never so low to the ground.

They are large doves, reaching almost half-a-metre and are richly coloured, with white head, purple breast, green wings with a conspicuous yellow stripe and bright yellow undergarments.

Their call is deep and resonant, with human-like attributes; “wollack-woo”. They feed on a variety of rainforest fruits, which may be quite large in size and are eaten whole.

When I first spotted this messy web, I could barely make out the spider. In its own right, it was tiny; a mere 3-4 mm long, but in the circumstances of its concealment, it was marvellously blended into the broader clutter of debris, at the centre of the stabilimentum (conspicuous feature of silk).

Under higher magnification, an enlarged, multi-coloured abdomen, together with a strategic positioning of legs, concealed the bulk of the spider’s cephalothorax. Upon closer scrutiny, its eyes were just distinguishable between its legs.

It turned out to be a species of Cyclosa, renowned for adding prey remains and other debris to their orb-webs. The function of silk decorations is generally associated with defensive strategies, but there is also a notion that it may increase attractiveness to prey.

In my research of Cyclosa, I read that, under threat, the spiders may vibrate the web, bringing motion to the detritus and in so doing, give an impression of a more expansive population.

I also read the abstracts of two independent studies, which seemed to contradict the findings of each other. One showed no significant tendency in attraction to webs with a stabilimentum, whilst the other revealed 150% more insects trapped than for undecorated webs. Both studies agreed that without detritus columns and silk decorations, spiders were attacked at a higher frequency.

For the sake of appearance, colour can make a world of difference. In tropical rainforests, a bright upper canopy, rich in blue and UV, and a dark understorey, rich in green and orange, contrasts two distinct light environments.

When discretion is important, bright greens blend better in the upper canopy, whereas dark browns have the advantage in the understorey.

When advertising an invitation to treat, as it were, bright blues glow advantageously in the upper canopy, whilst yellow and red signals optimise conspicuousness in understorey. The Hairy Red Pittosporum P. rubiginosum ssp. Wingii, of Australia’s tropical rainforests, is an excellent example of the latter.

Between a quarter and a third of the world’s wildlife has been lost since 1970, according to data compiled by the Zoological Society of London.

Populations of land-based species fell by 25%, marine by 28% and freshwater by 29%, it says.

Humans are wiping out about 1% of all other species every year, and one of the “great extinction episodes” in the Earth’s history is under way, it says.

Pollution, farming and urban expansion, over-fishing and hunting are blamed.

BBC News Website: Wildlife populations ‘plummeting’

WASHINGTON, DC – Sen. James Inhofe (R-Okla.), Ranking Member of the Environment and Public Works Committee, today expressed disappointment with the U.S. Department of Interior’s final decision to list the polar bear as “threatened” under the Endangered Species Act.

“Unfortunately, the decision to list the polar bear as ‘threatened’ appears to be based more on politics than science,” Senator Inhofe said. “With the number of polar bears substantially up over the past forty years, the decision announced today appears to be based entirely on unproven computer models. The decision, therefore, is simply a case of reality versus unproven computer models, the methodology of which has been challenged by many scientists and forecasting experts. If the models are invalid, then the decision based on them is not justified. It’s disappointing that Secretary Kempthorne failed to stand up to liberal special interest groups who advocated this listing.

“Lost in the debate is the fact that polar bear numbers have dramatically increased over the past forty years – a fact even liberal environmental activists are forced to concede. According to Canadian scientists, 11 of the 13 bear populations are stable, with some increasing. The U.S. Fish and Wildlife Service now estimates that there are currently 20,000 to 25,000 polar bears. These numbers are substantially up from lows estimates in the range of 5,000-10,000 in the 1950s and 1960s. Credit should be given to protection already provided the polar bear by way of the Marine Mammal Protection Act, the several international conservation treaties including the 1973 Agreement on the Conservation of Polar Bears and the U.S.-Russia Polar Bear Conservation and Management Act of 2006, as well as conservation, education, and outreach agreement with native peoples.

“Today’s decision will have far reaching consequences. Liberal special interests have employed hundreds of lawyers to try and convert current environmental laws such as the Endangered Species Act into climate laws. Yet the ESA is simply not equipped to regulate economy-wide greenhouse gases, nor does the Fish and Wildlife Service have the expertise to be a pollution control agency. The regulatory tools of the ESA function best when at-risk species are faced with local, tangible threats. Greenhouse gas emissions are not local. The implications of today’s decision, therefore, will undoubtedly lead to a drastic increase in litigation and eager lawyers ready to use this listing to do exactly what they have intended to do all along – shut down energy production.”

Press Release: Inhofe Says Listing of Polar Bear Based on Politics, Not Science