I have recently been living in Guyana's rainforest, and have consumed a large number of magoes. Now, I always assumed that a ripe mango would contain more calories than a green one. They certainly taste a lot sweeter. Is this actually the case? And i so, how does the mago aquire this additional energy if they are picked whilst still green and allowed to ripen afterwards?

This is a question my 11 yr old twins asked some years ago. We are still seeking an answer, an email to NASA did not give one so can one or NS readers help please.

Chlorophyll is green (reflects mainly green light) and is strongly selective in absorbing light in the red and violet regions to drive photosynthesis. But obviously the Copper Beech leaves reflect almost all the wavelengths that the chlorophyll is able to absorb.

The Copper Beech (or Purple Beech) tree has been selectively bred from the European Beech, so there is no evolutionary benefit to the colour.

So how does a Copper Beech thrive? It should be almost incapable of growth!

I was given some gerber flowers, and told that making a hole horizontally through the stem under the flower would keep them fresher for longer. Is this true? Is there any substance behind it whatsoever?

I found these strange pods (see photo) at the end of June last year on one of our south-facing shutters. We live in the French Alps at an altitude of about 750 metres. Over the following six weeks they did not appear to change. What are they?

John Donaldson, By email, no address supplied

While hiking through the forest near Arenal volcano with my family, we encountered the "furry stumps with claws" shown in the photos.  Can anyone tell us what they are called so we can do some more research on them?

???While hiking with my family through a forest near Arenal volcano in Costa Rica, we encountered the pictured plants, which appear to be furry and claw-covered stumps.  We would love to know what they are called so we can research more about them.

While hiking through a forest near Arenal volcano in Costa Rica, my family and I encountered these stumps which had apparently escaped from the Island of Dr. Moreau.  They appear to be fur and claw covered tree stumps.  We would love to know what they are called so we can search on-line for more information. 

Flowers co-evolved with their pollinators: that is why they find flowers attractive. This arrangement works to the benefit of both parties, so do humans get any similar benefits from liking flowers? The plants do, in that gardeners propagate them.

Come to think of it, are other mammals attracted to flowers?

Jim Simons, Cheltenham, Gloucestershire, UK

I found this leaf (pictured) in a park in Oslo a few weeks ago. What is the explanation for this pattern of green pigmentation?

Fredrik Størmer, Oslo, Norway