Butterflies, Bronze Bees and Big Hoverflies

20th August 2012
My wife was somewhat concerned (no doubt worrying about the fate of her brassica seedlings), when I asked her not to discard the nasturtium leaves that displayed plentiful clusters of Large White (Cabbage White!) butterfly eggs. I had watched Large White (Pieris brassicae) females dancing around various garden plants, looking for suitable egg-laying sites (they "taste" the leaves using chemoreceptors in their feet). Apart from the plants in the cabbage family, Large Whites are also attracted to nasturtiums.

I wanted the eggs left so that I could photograph the larvae (caterpillars) emerging. The eggs typically take 1-2 weeks to mature (depending on temperature) and I kept a close watch on the leaves for signs of life. I initially found one cluster where all the eggs had hatched and the larvae were consuming the old egg cases. This typically, is their first meal. On another leaf on the same plant, I found this cluster where hatching had just started. You can see one larva that is just emerging and a couple of empty egg cases. It's also clear to see the dark heads of the un-hatched larvae still inside the other eggs. This was taken with my MP-E 65mm macro lens at full-magnification (x5).

I'm particularly interested in seeing and recording solitary bees in and around the garden, but this time of year there seems to be more activity from solitary wasps. Earlier in the year (see Blog post) there had been lots of Harebell Carpenter Bees (Chelostoma campanularum) in our campanula flowers, and I had been ignoring some similarly-tiny (6-7mm) bees that were appearing in the flowers now. Luckily I took the trouble to check them out. They are from a group of Lasioglossum bees that exhibit this very attractive greeney/bronze metallic sheen. This one is resting in a campanula flower.

There are several bronzey-metallic species in the Lasioglossum genus amd they are difficult to differentiate from photographs. I did have an active colony on Lasioglossum smeathmanellum in my front garden earlier in the year, but these look smaller. Whatever the species, these are attractive little bees.

I noticed from following Buglife on Twitter, that the Hornet Hoverfly (Volucella zonaria) was their "Insect of the Week". Apparently, it was first spotted in southern England in the 1940s and has been gradually moving northwards. Recently there have been sightings in Chester and elsewhere in northern England. Buglife is running a survey and hoping to establish whether they are actively breeding in the UK or whether sighting are of migrants from the Continent. I made a mental note and decided to look out for it.

The very next morning my wife said "here's a creature that might interest you". On a garden plant was this very large hoverfly that certainly had some hornet-like features. I was really quite excited! I managed to grab a couple of shots before it flew off and then looked it up in my British Hoverflies book (Stubbs and Falk). I could see that it didn't look quite typical, so submitted an image to iSpot. Apparently, this is Volucella inanis, a similar, but different species. Never mind; this is another garden "first" for me, and another fine-looking insect!

[Click on an image for a larger view]


Photo comment By Peachez: Have seen hornet hoverfly 20.08.14 in North Essex

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