A small group of plant eating beetles have the curious habit of ejecting small globules of red liquid when they are irritated. All of them of the genus Timarcha, feed, probably exclusively, on plants of the hedge bedstraw (Galium mollugo). That is the situation in the photo. The liquid is usually produced through the mouth - so it is called the 'bloody nose' or in French - 'spit blood' beetle. It also can exude at the joints and in this specimen there is a small drop just behind the head. But why? In fact to the inquiring mind this is not the only question about its natural history. The books claim that the oozing blood frightens off predators. Only, I imagine if it has a nasty taste. One reference says that the 'blood' if placed on the gum of an aching tooth actually relieves the pain and that the effect lasts for days! I, personally, did not take to the idea of trying the taste, but I was able to check the acidity of the 'blood' and found it to be fairly acid with a pH of at the most 5.5, much more acid than human blood. This acid numbing liquid should deter and if a bird attacked one beetle and received an unpleasant taste, then it would probably not attack another! The liquid is not like our blood. The red colour is not due to haemoglobin.
The creatures are extremely sluggish, sloth like in creeping about the straggling plant. They have considerable powers of survival. This specimen fell in the water used to keep fresh its food plant. I thought it was drowned. I placed it in another container and after three days it began to move. Placed back on the plant it was soon eagerly chewing a leaf. Most of the eating would be carried out by the larva. This has a striking dark bottle green colour. When disturbed it tends to bends up rather like a wood louse. Both adult and larva are said to be more active at night. This group of beetles have no wings. The two wing cases which cover the true wings in beetles are here fused tight. Yet these beetles are relatively common. They somehow find their way to the food plant. There remains the uncertainty as to whether it only eats the hedge bedstraw. This is a close relative of the goosegrass or cleavers, the tough garden weed which has many small prickles on the leaves and stems and also the wild madder, which is even more tough and prickly. If the beetle is confined to just one species then its powers of search and find are even more remarkable! Especially as it as slow as a sloth.
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