Spiders and mites on gorse

Gorse is beautiful plant, although best viewed from a distance, rather than walked through, as it is incredibly spiny and prickly. The sharp spines are, however, a tremendous advantage if you are small enough to live within their protection. It is also a plant that is remarkably variable in terms of its flowering period and duration – some plants remaining in flower for up to six months – so it is incredibly valuable as a pollen and nectar source for pollinators.

Common gorse (Ulex europaeus) flowers, Galicia, Spain

Long-flowering individual gorse plants produce only few flowers at a time however, whereas short-flowering plants produce masses of flowers over a short period; like the wonderful blooms seen below in Galicia, Spain, at the beginning of June. Whilst we can admire this plant in the British Isles and in other places in Western Europe where it is present in its native range, it is worth noting that gorse is a very damaging invasive weed in many other parts of the world, such as New Zealand. It is extremely competitive and is damaging because it displaces many native plants, and acidifies the soil.

Common gorse (Ulex europaeus) blooming at Cabo de Bares, Galicia, Spain

A wide range of invertebrates – including weevils and moths – live and feed on gorse plants, but the most apparent ones are spiders, because of the webs they weave in an around the shoots and leaves. Some of these webs are, I think, very attractive, but also interesting to examine to see who, or what has constructed them!

Gorse spider mite webs (Tetranychus lintearius) on gorse.

Some of the most aesthetically pleasing constructions are made by tiny Gorse spider mites (Tetranychus lintearius). Quite how they get together to fabricate their webs, I have no idea (!), but they appear to construct a tent-like structure over the plant, which allows them to live and feed in relative safety! The gorse mites only feed on this plant alone, and can cause damage via their sharp stylets, so they have been adopted as biological control agents in regions where gorse is considered as a weed. Here is another photo (below) of their dense colonies, protected from the dew drops by their webbing.

Gorse spider mite (Tetranychus lintearius) web with dew drops. Galicia, Spain.

Spiders also take advantage of the spiky shoots to construct webs and reproduce. I came across this lovely Nursery web spider (Pisaura mirabilis) guarding her offspring. The female carries an egg-cocoon in her mouthparts (chelicerae) until the eggs are ready to hatch, when she constructs a tent-like web in which young can remain until they disperse. They look as though the are about to hatch in this photo (below) taken at the beginning of September. Many insects and spiders look after their offspring!

Nursery web spider (Pisaura mirabilis) guarding her cocoon. Galicia, Spain.

Another spider commonly found in gorse is the Wasp spider (Argiope bruennichi) which commonly builds its spiral webs on gorse plants: better to catch the many insects coming to feed on the gorse and heather flowers in heath-land habitats.

Wasp spider (Argiope bruennichi), Galicia, Spain

Gorse – especially western gorse or dwarf furze (Ulex gallii) – commonly occurs in association with other flowers, particularly heather species, as shown below.

Gorse and heather blooming in late September in Galicia, Spain.

I have to say, that these habitats are some of the most attractive places in the world, and it is a sensual pleasure – a visual feast – to walk through them and soak up the colours.

Gorse and heather blooming in late September in Galicia, Spain.

Finally, we must mention another common spider which is very common in gorse: the European garden spider (Araneus diadematus) . I love watching these predators catch and wrap up their prey, although at the same time I find it rather disturbing that innocent creatures, going about their business, can be trussed up and sucked dry in a matter of seconds! But that, I’m afraid to say, is Nature!

European garden spider (Araneus diadematus) on gorse. Galicia, Spain

Tarayre, M., Bowman, G., Schermann-Legionnet, A., Barat, M., & Atlan, A. (2007). Flowering phenology of Ulex europaeus: ecological consequences of variation within and among populations. Evolutionary Ecology21(3), 395-409.

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