Showing posts with label bee fly. Show all posts
Showing posts with label bee fly. Show all posts

Wednesday, 19 April 2017

Taking It Easy



What a lovely day for wandering along the beach and taking it easy after our exertions down the valley. I see that we have another of those Bee flies that we were discussing a few weeks back (see The Sweet Smell of Rain) investigating the sand. Quite an absorbing pastime and there are hobbyists who collect sand, studying its composition from places around the world. The bit that the bee fly is studying for instance contains dark grains, pure white grains and at least fifty shades of grey in between. The colours are determined by the mineral content and the shape depends upon whether it has been washed down from the hills or transported by wind and waves. Ours is angular suggesting that it has come down the valley like us and the colouration is typical of quartz and chert with that odd orange bit by his abdomen probably coming from one of the iron bearing rocks that we observed in How To Get Blood Out Of A Stone.

Let's walk along the back of the beach and see what else we can find. Those bunches of strap like leaves will throw up fragrant blooms of white Sea Daffodils in the summer but we have one common beach plant blossoming here and now and that's Sea Rocket. The seed pods have a very high concentration of erucic acid which is an omega 9 fatty acid and has a bit of a story behind it. You may be familiar with great yellow fields of rape, from which we get rapeseed oil. Rape and sea rocket are closely related and both contain high levels of this acid. We cultivate rapeseed oil for biofuel, animal feed and edible oil but the high levels of erucic acid became a cause of concern after laboratory tests in the 1970s showed that if you stuffed rats full of the stuff then it had a toxic effect on the heart. To be honest, if you pig out exclusively on anything it will probably do you harm – even water can poison you in high enough doses. Enter two bright sparks from the University of Manitoba in Canada who bred rapeseed low in erucic acid and called it Canola oil. Nowadays we just genetically modify the plant of course and canola is widely marketed as the healthy cooking oil. I'll let you make your own mind up on that one.

Here's a pretty little lady, she's a Long tailed Blue. Not as showy as the male who has a lot more blue on his upper wings but it pays not to be too conspicuous when you're sitting there egg laying. This maybe what she has in mind now. Her caterpillars feed on a wide range of leguminous plants in the Fabaceae family such as this Cretan Ebony which is just coming into flower. Shall we take a wander down to the sea and clamber along those interesting looking rocks over there?







That seems like a nice place to stop and watch the marine world go by. Not much in the way of fish today... the odd shore crab scuttling about... but there's some seaweed down there which may be harbouring some microscopic life. Let's have a look. Ah, our old friends the diatoms, the very basis of the food web. These are marine diatoms and different to those that we found under the dripping stalactite in A Recipe For Life.
Those wedge shaped ones often cluster together, narrow ends facing inwards, so that they make a complete circle like a flower head. I expect that we disturbed them when we rudely hauled them out of the sea and plonked them on a microscope slide. I think we'll rinse the slide and put them back. You know, it's almost warm enough to join them in there. Maybe in a couple of weeks. When the sea's had a chance to warm up a bit.

The Extra Bit

If you'd like to become an arenophile and collect sand as a hobby there's a society just for you: http://sandcollectors.org/become-a-collector/






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LINKS:
Share your nature thoughts, photos and comments on Naturalists (the facebook page that accompanies this blog)
See detailed pictures on Flickr
Read more about the flora and flora of the island in The Nature of Crete (Flipboard Magazine)

Wednesday, 29 March 2017

The Sweet Smell of Rain

Ah, the sweet, rich smell of rain. That distinctive scent wafting up our nostrils comes from a naturally occurring plant oil that is absorbed by soil and rocks during dry periods. When rain falls, the oil is released into the air along with an organic compound called geosmin that's produced by the bacteria in wet soil. It’s this combination that creates that clean, earthy, “just-rained smell”. Rain itself has no odour. Even acid rain looks and smells just like the normal kind.



We’ve had rather a lot of rain recently but before we go down and see what effect it has had on our stream I noticed this little patch of ground when we emerged onto the track last week. It is regularly cultivated later in the spring but let’s have a look and see what’s taken hold before the rotavator moves in. Plenty of Wood Sorrell here at our feet and some stands of White Mustard in front of the Date Palms but just check out these little pink flowers. These are Small Herb Robert and they are certainly attracting the little Bee Flies. As their name suggests they are flies that have evolved to protect themselves by looking like bees. Whenever you come across an animal that seems to have two contradictory names the second name tells you what it is and the first name tells you what it resembles. Thus a Whale Shark is a shark that resembles a whale and a Curlew Sandpiper is a sandpiper that looks like a curlew and not the other way around.


The rain has certainly put a bit more vim and vigour into our stream; it looks as though it can’t wait to get to the sea. Let’s have a dig along the bank and see what turns up. Earthworms – now these are quite exciting for me because I don’t see many in our arid climate out here. The one on the right is an adult Lobworm and the one on the left looks to be a juvenile. How can you tell the difference? Earthworms are hermaphrodite (both male and female) and when they mature they develop a ‘saddle’, technically called the clitellum, which contains the eggs. After two earthworms have mated the sperm from worm 1 is transferred up the body of worm 2 to the saddle (and vice-versa), the clitellum secretes material that forms a ring which the worm then slides out of and injects the eggs and sperm into it. The ring seals itself into a cocoon in which the baby worms develop, emerging as fully formed juveniles two or three months later. Now you know all about the sex life of the earthworm. You’ve always wanted to know that, haven’t you?

I see that we have a diminutive cascade running into our stream from the valley side. Do you fancy a climb? We could do with a change of scene. There are quite a number of White Hedge-nettles about: another totally misleading name as they are not nettles at all and they don’t always grow in hedges as you can see. If you look at the flower shape you can see that they are similar in design to Sage, Rosemary and many of the other culinary herbs and that is because they are in the same family. Nettles are in a completely different family and their flowers are totally dissimilar and very dull in comparison. Mind you, you can eat nettles but as far as I know there are no recipes for White Hedge-nettles despite their family connections. That may be one for our friend Haris Saslis at Forage Crete to investigate.






Here’s another one of those pesky flies trying to look like something it isn’t. It has all the colouring and shape of a wasp but it’s a Hoverfly. This one is male and they usually appear earlier in the spring than the females giving them a chance to mature (you know how long it takes us boys to grow up –I’m not sure I’ve got there yet). How do I know it’s a male? The eyes are set very close together and appear to almost join in the middle. In the female the eyes are set further apart.






Quite a nice view of the opposite side of the valley from up here and we’re almost back to the coast. Look back down to the track a moment. There, sitting on top of that telegraph pole – a kestrel. They often patrol up and down this valley. They’ll be breeding soon, nesting in holes and scrapes in the cliffs or maybe in an old crow’s nest. They can lay up to six or seven eggs and like many birds they are r-strategists. That is they spread their parental care over a number of offspring allowing the strongest to survive. This compares to animals like ourselves who are k-strategists (in the developed world at least) who have fewer offspring but devote considerable care and attention to ensuring that they all survive. I sometimes wonder, from a purely biological rather than a humanitarian viewpoint, whether we in the developed world are correct in imposing our k-strategy thinking on those parts of the world where the r-strategy prevails.

And on that thought I think we’ll call it a day and make our way back down to the track. Watch your footing, going down can be more treacherous than climbing up and I don’t want to pick you up in a heap at the bottom.

The Extra Bit

Just in case these blog posts give you a taste for visiting the Mediterranean I am hosting a new facebook site called Mediterranean Island Insights which features posts from bloggers on various Mediterranean Islands. Here is the link: https://www.facebook.com/groups/1309179912496006/


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LINKS:
Naturalists (the facebook page that accompanies this blog)
See detailed pictures at http://www.inaturalist.org/login  (search - people-stevedaniels-observations)
The Nature of Crete  (Flipboard Magazine)

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