Tag Archives: grass

Let your dandelions and other flowering ‘weeds’ be

This last couple of weeks parts of my daily walks have been accompanied by, the to me, unwelcome din of motor lawnmowers as lots of my fellow villagers strive to turn their lawns into ecological deserts. One of my neighbours has, to my knowledge, cut his lawn five times since the beginning of March, me I’ve done my spring cut and that’s it until autumn.

An ecological desert 😦

This mania for close-cropped lawns, sometimes ‘artistically’ striped, is, I think, the fault of my grandparent’s generation, which took a municipal park attitude to gardens, especially the bit that the neighbours could see; close-cropped, weed-free grass with regimented flower beds, also equally weed-frees. Out of sight, back gardens could be less manicured, and depending on the space available, might include a vegetable garden (also scrupulously weed-free), and a patch of lawn to be used by children for ball games and other activities. Unfortunately they drummed this philosophy into their children, who in their turn, with only a few exceptions (me for one), passed this fetish on to my generation. Sadly, my father, a keen gardener, also espoused this view as did the parents of all my friends. I spent many a grumpy hour removing dandelions and thistles from our front lawn and flower beds at my father’s behest!

So what are these weeds that so many people seem to hate? To those growing crops of economic value, be they agricultural, horticultural or silvicultural, then I guess the following definitions are very reasonable and relatable.

Plants that threaten human welfare either by competing with other plants that have food, timber of amenity value, or by spoiling and thus diminishing the value of a product

Weeds arise out of the mismatch between the habitats we create and the plants we choose to grow in them

Begon, Harper & Townsend (1996)

A plant that originated under a natural environment and, in response to imposed and natural environments, evolved and continues to do so as an interfering associate with our desired plants and activities” Aldrich & Kremer (1997)

There are more tolerant descriptions of weeds available, which are much more in accord with my views:

What is a weed? A plant whose virtues have not yet been discovered” (Emerson, 1878)

, “A weed is but an unloved flower!” (Wilcox, 1911)

A plant condemned without a fair trial” (de Wet & Harlan, 1975)

I have, as I have mentioned several times already, been doing a lot of walking during the covid pandemic, or should it now be referred to as the Covid Pandemic? At this time of year, Spring, the early flowers of the hedgerows and roadside verges are alreday out; cherry plum (Prunus cerasifera), blackthorn or sloe (Prunus spimosa) and closer to the ground, but as equally pretty, daisies (Bellis perennis), dandelions (Taraxacum officinale), Lesser Celandines ( Ficaria verna (although some of you may know it as Ranunculus ficaria), and Wood Anemones (Anemonoides nemorosa). The latter two species, although relatively common, are unlikely to be found in the average garden, as they have fairly specific habitat requirements.  Daisies and dandelions on the other hand, are pretty much ubiquitous, although the former do not attract as much opprobrium from the traditional gardener as dandelions do. This is a great shame, as ecologically speaking dandelions are an extremely important resource for pollen and nectar feeding insects.

Given the concerns about the decline of insects in general over the last forty years, we should be celebrating the dandelion, not trying to eradicate it from our lawns. Just feast your eyes on some of the beauties that I have seen over the last few days.

Pollen beetles March 20th 2021

Male tawny mining bee Andrena fulva – Sutton March 25th 2021

Bumble bee, Sutton March 30th 2021

Seven spot lady bird, too early for aphids, Oulton Road March 30th 2021


Peacock butterfly in a very striking pose, Guild Lane, Sutton, April 3rd 2021.

I’m not alone in my love of dandelions 🙂

We shouldn’t forget the humble daisy either. It provides nectar to many butterfly species, including among others, the Green Hairstreak, the Grizzled Skipper, the Small Copper and the Small White. They are also important resources for honey bees (Raquier et al., 2015), bumblebees and hoverflies (Blackmore & Goulson, 2014).

A nice patch of daisies.

Domestic gardens, if managed correctly, have tremendous potential as reservoirs of insects and other invertebrates of ecological importance (Davies et al, 2009). The easiest thing that you can do to help the insects is to reduce the frequency at which you mow your lawn and grass verges. To sum it up in a nutshell, the less you move, the more flowers you get and the more flowers you get the more nectar and pollen feeding insects you make happy, some of which can be rare and endangered (Wastian et al., 2016).  

The less frequently you mow, the more flowers you get. The more flowers you get, the more bumblebees you get (George, 2008).

It is not just flower feeding insects that benefit from reducing your lawn mowing activities; grass feeding insects also benefit from longer grass ( Helden & Leather, 2005) and if, for some strange reason, you are not a great fan of bugs, just remember that the more bugs you have the more birds you will attract (Heden et al.,  2012). So do your bit to save the planet, be like me, only mow your lawn twice a year.

References

Aldrich, R.J. & Kremer, R.J. (1997) Principles in Weed Management. Panima Publishing Corporation.

Begon, M., Harper, J,L. & Townsend, C.R. ( 1996) Ecology, 3rd Edition, Blackwell Science, oxford.

Blackmore, L.M. & Goulson, D. (2014) Evaluating the effectiveness of wildflower seed mixes for boosting floral diversity and bumblebee and hoverfly abundance in urban areas. Insect Conservation & Diversity, 7, 480-484.

Davies, Z.G., Fuller, R.A., Loram, A., Irvine, K.N., Sims, V. & Gaston, K.J. (2009) A national scale inventory of resource provision for biodiversity within domestic gardens. Biological Conservation, 142, 761-771.

De Wet, J.M.J., Harlan, J.R.  (1975) Weeds and domesticates: Evolution in the man-made habitat. Economic Botany, 29, 99–108.

Emerson, R.W.(1878) The Fortunes of the Republic. The Riverside Press, Boston, USA.

Garbuzov, M., Fensome, K.A. & Ratnieks, F.L.W.  (2015)   Public approval plus more wildlife: twin benefits of reduced mowing of amenity grass in a suburban public park in Saltdean, UK. Insect Conservation & Diversity, 8, 107-119.

George, W. (2008) The Birds and the Bees: Factors Affecting Birds, Bumblebees and Butterflies in Urban Green Spaces, MSc Thesis, Imperial College, London.

Helden, A.J. & Leather, S.R. (2005) The Hemiptera of Bracknell as an example of biodiversity within an urban environment. British Journal of Entomology & Natural History, 18, 233-252.

Helden, A.J., Stamp, G.C. & Leather, S.R. (2012) Urban biodiversity: comparison of insect assemblages on native and non-native trees. Urban Ecosystems, 15, 611-624.

Lerman, S.B., Contostac, A.R., Milamb, J. & Bang, C. (2018) To mow or to mow less: Lawn mowing frequency affects bee abundance and diversity in suburban yards. Biological Conservation, 221, 160-174.

Requier, F., Odoux, J., Tamic, T.,Moreau, N., Henry, M., Decourtye, A. & Bretagnolle, V. (2015)  Honey bee diet in intensive farmland habitats reveals an unexpectedly high flower richness and a major role of weedsEcological Applications, 25, 881–890.  

Wastian, L., Unterweger, P.A.& Betz, O. (2016) Influence of the reduction of urban lawn mowing on wild bee diversity (Hymenoptera, Apoidea). Journal of Hymenoptera Research, 49, 51–63.

Wilcox, E.W. (1911) Poems of Progress and New Thought Pastels. London: Gay & Hancock, 1911.

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Not all aphids live on leaves

I haven’t written about aphids for a while, so I thought I would indulge myself and tell you about a few of my favourite aphids.  Most people’s perceptions of aphids (assuming that they know what  aphids are of course) is that they live on leaves.  They will I think, also possibly know that they are usually found on the undersides of leaves, although I may be assuming too much here.  In fact, many species of aphid do not live on leaves; a number of species feed on shoots, twigs and branches and some actually feed on the main trunks of trees.  Yet other species live on the roots of trees and herbaceous plants, such as the apple-grass aphid, Rhopalosiphum insertum which can be a pest of apples and cereals, feeding on the leaves and buds of apples and the roots of grasses and cereals.   Another root-feeding aphid that is a double pest, is Pachypappa tremulae, the spruce root aphid, which host alternates between the aerial parts of aspen trees and the roots of Norway spruce; easily visible when infesting the roots of young potted plants due to the presence of white waxy tufts on its rear end.

Some aphids not only live underground feeding on roots, but are entirely dependent on being farmed by ants e.g.  Tetraneura ulmi, which host-alternates between elm and grass roots, and  Forda formicaria, which host-alternates between Pistachio trees and grass roots.

Forda_formicaria_hirsuta_root_aphid_03-03-13_3

http://www.aphotofauna.com/images/bugs_homoptera/bug_forda_formicaria_hirsuta_root_aphid_03-03-13_3.jpg

Both these aphids are looked after or ‘farmed’ by the yellow meadow ant Lasius flavus in exchange for donations of honeydew.

Lasius%20flavus%202

These two aphid species, along with a number of others, have an enlarged anal plate surrounded by special hairs that form the so-called trophobiotic organ.  This acts as a storage device that allows the aphid to accumulate honeydew ready for the ants to remove.  Those aphids that have a more casual (facultative) relationship with ants, do not have this organ which is the basis of this remarkable mutualism.

Another aphid that is farmed by ants, but in a somewhat different way, is the rather larger rose root aphid, Maculolachnus submacaula, which as its name suggests, feeds on rose roots.  In this case, the ants allow the aphids above ground but only in an ant tunnel, similar to those produced by termites when they are infesting a building.  I have only ever been lucky enough to see this aphid once, some 35 years ago in Norwich when I was doing my PhD and noticed things that looked like termite trails running up the main stem of one of my rose bushes.  On breaking them open, well I am a curious entomologist, I found to my surprise not only ants but large brown aphids.

Maculolachnus submacula nest

http://jardiweb-floralbum.forumsactifs.com/t1797-colonie-de-pucerons

for a better view of the aphid see http://www.afripics.co.za/home/products/product.php?ProductID=1301564582

But of course the really spectacular ones are those that feed on branches of trees such as the giant willow aphid Tuberolachnus salignus (famous for its sharks fin) and those from the genus Stomaphis which feed through the bark of trees such as oak and

Tuberolachnus

sycamore and are possessed of truly enormous mouthparts such as those of Stomaphis aceris which feeds on sycamore

Stomaphis query aceris

This one, despite its enormous mouthparts, is quite difficult to find as it hides underneath the bark, but luckily it is ant attended so if you see ants scurrying around on the bark of sycamore and disappearing underneath loose flaking bits, it is a good bet that if you gently lever off the loose bark you will find yourself in the presence of this weird-looking creature.

The more I learn about aphids the more I find to marvel at.  Aphids really are remarkable and we know so little about so many of them and their weird and wonderful life styles.

Useful References

Blackman, R.L. & Eastop, V.F. (19 94) Aphids on the World’s TreesAn  Identification and Information Guide.  CABI Publishing. http://www.aphidsonworldsplants.info/index.htm

Evenhuis, H.H. (1968)  The natural control of the apple grass aphid,  Rhopalosiphum insertum, with remarks on the control of apple aphids in general in The Netherlands. Netherlands Journal of Plant Pathology, 74, 106-117  http://link.springer.com/article/10.1007/BF02309501#page-1

Farrell, J.A. & Stufkens, M.W. (1989) Flight activity and cereal host relationships of Rhopalosiphum spp. (Homoptera: Aphididae) in Canterbury New Zealand Journal of Journal of Crop and Horticultural Science, 17, 1-7  http://www.tandfonline.com/doi/abs/10.1080/01140671.1989.10428003

Ivens, A.B.F., Kronauer, D.J.C., Pen, I., Weissing, F.J. & Boomsma, J.J. (2012)  Ants farm subterranean aphids mostly in single clone groups – an example of prudent husbandry for carbohydrates and proteins?  BMC Evolutionary Biology, 12:106 http://link.springer.com/article/10.1186%2F1471-2148-12-106

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