Tuesday, July 12, 2016

Longhorn beetle Strangalia maculata


It's the season for hogweed flowers, which brings with it a host of interesting insects that either feed on its pollen and nectar or hunt other insects on those flat umbels of tiny flowers.

There's also an added bonus for the ageing naturalist because hogweed inflorescences are mostly held aloft on 4-5 foot tall stems. It's so often the case with macrophotography that you either need to crouch down or get down on your hands and knees to take photos. My ageing knees make that increasingly painful but when they're feeding on hogweed insects present themselves conveniently at head-height.















This rather beautiful longhorn beetle is the one that I've always known as Strangalia maculata but which is now called Rutpela maculata. It seems to particularly favour hogweed flowers.















Each individual flower in a hogweed umbel only produces a very small volume of nectar but insects can crawl over them to collect it without expending much energy, so even though each individual reward is tiny there's ample net energy reward for less energetic insect species like this colourful beetle.
















Hogweed umbels also provide a convenient mating platform .... thanks to bison (see comment below) for identifying these two longhorns, photographed in Weardale a day after those above: 'The pair enjoying a romantic moment in the final picture look like Pachytodes (or Judolia) cerambyciformis. I'm looking at the all-dark antennae & legs, and the pinkish-brown colour of the elytra.' 


















You can see the elytra patterns a little better from this angle and I'm wondering now whether this is Judolia sexmaculata, the three-banded longhorn beetle, which according to some sources is a nationally scarce species......


4 comments:

  1. It is impressive.
    I know how you feel, I too like Hogweed and for the same reason.

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    1. Have to treat my knees with respect these days, Adrian!

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  2. I'd tentatively suggest that you may have encountered more than one species of longhorn on this occasion.
    The pair enjoying a romantic moment in the final picture look like Pachytodes (or Judolia) cerambyciformis. I'm looking at the all-dark antennae & legs, and the pinkish-brown colour of the elytra.

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    1. Thanks - your help much appreciated. I've updated the caption.

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