Nature Notes April 2021

Food for insects – April 2021

Sometimes in February, certainly this year, and definitely in March, impregnated queen bumblebees emerge from their winter solitude in order to find food and water. For the queen bumble bee, this is a very vulnerable time. Pollen and nectar sources are scarce, and she’ll need to find both very quickly in order to survive. The nectar gives her energy whilst the pollen helps her to replace vital body fats. It also provides protein to help her ovaries mature, and is needed later to feed her brood.

It is so easy for gardeners to provide the ideal source of food – spring bulbs. The pictures below show how accessible food is to reach in these predominately single flowered plants. They have the added advantage of giving us such pleasure too on cold windy or wet days and they are perennial and are often prepared to spread all over the garden without any human intervention.

Crocuses. Pollen is easily seen so the plant can be pollinated and used as food for the bees too. There are even clear guide lines leading to the nectar source at the base of the petals.

Hellebores & primroses both single flowered with clearly visible pollen & conspicuous guide lines.

Aconite
Anemone blanda
Wood anenome
Daffodil

During this time winter flowering shrubs and plants, such as mahonia, willows, rosemary, winter heathers, blackthorn, berberis provide a vital life line for bumble bees.

Site of a bumble bee nest – highlighted by the pink circle, a bumble bee entering the nest. (not my photo)

Once the queen bumble bee has recovered, her next task is to find a suitable place to nest such as an abandoned rodent hole, tussocky grass or even a bird’s nesting box.

Usually once the nest site has been located, the queen bumble bee will build a little wax cup inside it, which she will fill with nectar to sustain her whilst she incubates her eggs. She’ll also create a further wax cell, in which she will deposit a mound of pollen, and then lay her eggs on top of it. She incubates the eggs by lying on top of them and by vibrating her flight muscles to generate heat up 30 ℃!

After about 4 days, the eggs hatch into larvae (these look a little like maggots). The larvae continue to feed and develop, and will go through a number of stages in development (shedding their skin 3 times) until after about 14 days, they produce silken cocoons and pupate. Within the pupae, the larvae shed their skin once more, and undergo metamorphosis. After about 14 days, the little grub-like larvae are transformed into young bumble bees, which bite their way out of their cocoons.

The first bees to emerge from these cocoons are young female worker bees.

Meanwhile, the queen has already laid more eggs that are also in development.

The newly emerged workers will be a great help to the queen in rearing the rest of the brood. Within a day or two, these workers will set about helping the queen, initially with nest duties, but some will then go out to forage for pollen and nectar for rearing the next brood. A colony of bumble bees could have between 50 – 500 workers, but will commonly consist of around 120 to 200.

At some point, the queen will stop producing workers, and will switch to rearing males and young queens. Once the males have emerged, they will soon leave the nest in search of a mate.

The young queens may remain in the nest for a while, laying down fat reserves in preparation for the winter hibernation. In the case of bumble bees, the whole colony will die, except the new queens. The new queens leave the nest, mate, then hibernate, and re-emerge the following year to establish new colonies and so the next generation of bumble bees begins.

Top Ten

The top 10 garden pests and diseases for 2020 have been published by the Royal Horticultural Society (RHS) in their 25th annual pest and disease ranking report.

In order to conduct the research, the gardening charity looked into the top pest complaints made throughout the country last year. At the top of the list came slugs and snails back to the top after being taken over by the box tree caterpillar for 4 years.

  1. Slugs and snails
  2. Vine weevil
  3. Box tree caterpillar
  4. Ants
  5. Woolly aphid
  6. Glasshouse red spider mite
  7. Fuchsia gall mite
  8. Glasshouse thrips
  9. Rosy apple aphid
  10. Capsid bug and glasshouse mealybug.

Honey fungus and pear rust were named the top diseases by the RHS, closely followed by leaf spot and canker of prunus.

But are they really pests?

At a time when insects are in serious decline in the UK, some environmentalists and gardeners hopefully believe that we should welcome all life and promote rich biodiversity everywhere. Leading climate crisis campaigner Chris Packham describes this as being “a bit more tolerant.”

“If you build a garden space that’s attractive not only to you but to other species, they will come. If you build it, they will come – and when they do come, you need them,” Chris says “You might not think that you need wasps and pigeons and mice but if they’re there, they’re doing a job, and without all of those jobs being done, your community won’t be sustainable and as complete as possible. So never dial ‘P’ for Pest control if a wasp turns up in the corner of your shed, just let them go about their business. Dial ‘T’ for Tolerance instead.” Taken from his book ‘Back to Nature’ recommended last month.

Who Did This?

I have only just noticed these holes in a gate post that I pass every day. It looks as if it is a work in progress with one perfectly round hole and others being worked on. I can only assume this is the work of a woodpecker but I am surprised that it would work so near the ground and where people are moving to and fro frequently. It must have spotted easy pickings in the rotting post. Neither have I either heard or seen it. Has anyone got other ideas? Could it be an insect?

Wild Daffodils

The ‘native’ daffodil. Photo taken by Sue Hutton There seems to be some debate about whether we have a native daffodil in the UK. I have been looking in various wildflower books and some recognise a wild native daffodil and others do not. For example The Concise British Flora in Colour by W. Keble Martin does not include a picture of a daffodil at all whereas Majorie Blamey, Richard Fitter and Alistair Fitter in Wildflowers of Britain and Ireland do In fact they list 4 types the most well known one of which maybe the Tenby daffodil (Narcissus psuedonarcissus that has naturalised in Wales but can be bought from nurseries and on line. Wild daffodils tend to be daintier and more miniature than the common garden daffodil. Locally wild growing daffodils have colloquial names such as Lent lily, averill, bell rose, bulrose, chalice flower, common daffodil, daffy-down dilly, eggs and bacon, Lent cock, Lent rose, trumpet narcissus and yellow crowbell.

Book recommendation

Wild Flowers of Britain and Ireland by Marjorie Blamey, Richard Fitter and Alastair Fitter.

This is a real ‘go to’ book for identifying wildflowers. It is now in its second edition. It was written by 3 old friends who had each spent a lifetime of love and the study of wildflowers. The pictures are painted and illustrated in colour showing each plant’s flowers and other notable features such as fruits, buds and leaves. Even better the flowers are usually life-size. There are maps in the left margin to show the distribution of each plant.

End Piece

By now wild garlic is coming into abundant leaf and in the woods the pungent smell is everywhere especially as you knock against the leaves. Another year has gone by! Wild garlic pesto is a delicious alternative to the more usual basil pesto. The same ingredients can be used – pine nuts, parmesan cheese (or whatever you have), olive oil or walnut oil and the garlic. It is an easy recipe and the pesto freezes well in small batches for use as a pasta sauce on cold winter days.

By the time you read this another joyful sign of spring may have happened. Members of the swallow family may be back with us for the summer.

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