The Wild Side of Beth Chatto Gardens: a lull before the first storm of autumn…

Early October can be such a wonderful time. Still warm enough for shorts, still nature going about its preparations for the coming cold, seemingly with increasing urgency. And the first few days of the month this year were just that in the Beth Chatto Gardens, although with the first named storm of the season, Amy, due in a day or two, things could change rapidly… Thankfully I had the opportunity to make a couple of visits, both unfortunately rather short.

For now, the gardens are looking fruitful, showing some of the stresses of a multi-drought summer, but still in fine fettle. And for the insects there are still all manner of nectar and pollen resources out there to be exploited:

The most obvious visitors are still the butterflies, albeit in reduced numbers and diversity. Red Admirals, Commas and Large Whites were the commonest, with a very few Small Coppers, Small Heaths, Common Blues and Holly Blues, the latter by now probably on its third generation of the year.

Likewise, especially around the ponds, dragonflies and damselflies were still noticeable, basking, hunting and mating: Migrant Hawkers over the water, Common Darters everywhere including egg-laying couples in tandem, and Willow Emeralds, again some in mating formation, in the trees and marginal planting.

In the woodland garden, the leaves are colouring rapidly, especially that harbinger of autumnal glory Amelanchier. 

The Oak leaves bear their customary array of galls, here Spangle Galls although the smaller, darker ones may well indicate they have been hyper-parasitized. ‘Big fleas have little fleas, little fleas have lesser...’ etc comes to mind!

Spangle galls are caused by tiny wasps, but the pustular galls on Alder leaves are caused by even tinier mites, Eriophyes laevis.  And this leaf also has a leaf-mine, the manifestation of someone feeding inside the leaf (but not triggering abnormal growth, hence it is not a gall). Leaf-mines can be caused by a variety of insects, from moths to beetles, but this is made by the larva of a leaf-mining fly Agromyza alnivora. One leaf and two identifications without ever seeing the organism, just their symptoms.

A few Ivy plants around the shady areas were, as always, buzzing with life attracted to the vital late-season nectar and pollen source of their flowers.

Hornets were particularly active on the flowers, drinking the nectar for themselves, then flying menacingly through the greenery like  sharks hoping to pounce on an unfortunate insect to kill and take to their nest.

But it is thirsty work being a Hornet! Only males seemed to be visiting this watering-hole.

We don’t have much Ivy in the main part of the gardens, which probably explains why I was able to watch an Ivy Bee feeding on Astrantia. The bees are supposed to feed almost exclusively at Ivy, though in extremis may turn to members of the Daisy and Heather families. Perhaps Astrantia is a good alternative too: after all the Ivy family and Carrot family are closely related, and Hedera and Astrantia share a similar contracted umbel flower form.

By October  the power is draining from the sun’s rays so there are insects to be found basking to warm up. Crane-flies, here Tipula paludosa, seem now to be coming out in reasonable numbers, ungainly fliers and fair game for any insectivorous bird (or dragonfly).

Perhaps this Hairy Shieldbug had selected a sun-warmed bed among the insulating fur of a Cardoon seed-head as its cosy winter refuge?

Otherwise my eyes turned repeatedly to the late-flowering nectar and pollen sources. Honeybees were on a wide range of flowers, especially from the Daisy and Scabious families; bumblebees too, especially Common Carder-bees at the moment, and they can continue flying as it cools, given they have their own fur coats.

And where there’s prey, there are predators, although the success rate of this Flower Crab-spider may well be limited by its choice of backdrop…

It was good to see one of our larger hoverflies, the wasp-mimic Wasp Plumehorn Volucella inanis, an Essex Red Data species that has only infrequently been seen before in the gardens. Until we compile the Beth Chatto biolist I remain at the mercy of my memory, but Google shows me at least one previous example, from August 2023…

Wasp Plumehorn lives as a parasite in the nests of wasps and Hornets. And there are many other parasites that also contribute to keeping natural balance in the garden. One group is the tachinid parasite-flies, such as Tachina fera, whose larvae feed inside lepidopteran  caterpillars.

Then there was another Locust Blowfly Stomorhina lunata. These are scarce immigrants to UK from southerly climes where they breed, their larvae being parasites of locusts. We had one here about eight years ago, and then a small influx in early August this year, so maybe our native grasshoppers and bush-crickets should watch out…

And finally, the real prize of these visits, this gorgeous fly Ectophasia crassipennis, also a parasite, but of shieldbugs. Related to the equally beautiful Phasia hemiptera which was first seen in the garden in late July, when I was otherwise occupied, Ectophasia is even rarer, with only one previous Essex record I know of, and it is the first I’ve seen in this country.

As usual, the Beth Chatto Gardens came up with the wildlife goods. But what was especially remarkable was that my second visit lasted just 15 minutes. And in that short space of time I saw all three of the last-mentioned specialities, AND heard a Cetti’s Warbler singing, another garden first!