Writes for Wildlife

celebration and protection of the natural world

Category: Science Communication

Colorado Potato Beetle (Leptinotarsa decemlineata)

The Colorardo Potato Beetle is a fascinating insect, and although it is not native to the UK, I once found one, and that event, and all that followed inspired this post.

Colorado Potato Beetles are striking in appearance, around the size and shape of a ladybird but the wing cases have alternating black stripes with bands of orange or yellow, running along their length. There are usually 5 black stripes on each wing case and this gives rise to its other name: the ten-striped spearman.

Colorado beetle identifiaction: from top eggs, adult beetle & larvae. Taken from UNECE Guide to Seed Potato Diseases, Pests and Defects. (Can be found here).

This distinctive little beetle is native to Mexico, and the southern US including the state of Colorado. It is primarily seen as a pest by humans, as it feeds voraciously, breeds vigorously and is commonly resistant to pesticides. The food plants of choice are, as the name suggests, are potato crops. However these beetles also feed on tomato and aubergine plants and a native crop called the ‘buffalo bur’. A heavy beetle infestation can cause significant damage to the plant and may even defoliate an entire crop.

So why I am writing about a little stripy Mexican beetle? We do not have Potato beetles in the UK, we do however have a lot of potatoes. Potato crops are a large part of the farming industry in the UK. Over 6 Million tonnes were produced in 2017. (Reference)

 The beetles can breed up to three new generations during one potato growing season, and therefore one beetle can quickly become hundreds. The threat of potato beetles arriving in the UK is real, and thus they are a Notifiable species.

What does notifiable mean?

If you find a potato beetle in the UK you are legally required to notify the government. This is what happened to us. I found a potato beetle in a packet of spinach leaves. The amazing thing about this is that we even knew it was a potato beetle. I love wildlife and the natural world, but I won’t pretend that I can identify, on sight, every species of beetle from around the world. The kids have a board game called bug bingo*, and one of the ‘bugs’ on the board is a potato beetle, so even the kids recognised it immediately when we found it.

Colorado Beetle on my thumb.

The spinach leaves had come from Spain, so I did a little googling and it was only then that I discovered that they are a notifiable pest in the UK. Having worked as a vet in the UK shortly after the Foot and Mouth Disease Outbreak, and BSE, I was aware of notifiable diseases but I had never reported an insect before!

These beetles are hardy. I mean really tough. The one I had was still alive and crawling around despite having been refrigerated, and enclosed in a bag for days.

When I notified the government, at my local office in Perth, by email. I sent a photo and asked what to do next. The office sent down a member of staff to identify and collect the beetle and remove it. He told me that these beetles, despite originating in warm tropical and temperate climates, can actually withstand freezing. Specimens have been stored in the freezer and yet quite happily started walking around again after defrosting. This is what makes it such a threat to the UK potato crop. Beetles which ravage potato plants, can produce numerous offspring, may be resistant to pesticide and can also survive our colder winter weather could cause a serious problem. The best way to protect against them is to prevent them coming into the country.

Biosecurity is so important and the potato beetle is just one example. We import many food stuffs from the continent that may carry a beetle. It can occur with any of the usual crops on which potato beetles feed, but also on crops sown in a field which grew potatoes in a previous season.

The beetles mate before overwintering in the earth, this means that a female emerging from the soil in spring is likely to already be carrying viable eggs, and able to lay them when she locates a host plant. So it only takes one female carrying eggs to get in to the UK to establish a colony, hence the vigilance.  

If you find a Colorado beetle, in the UK, you must notify the government. I have attached the relevant contact details here, along with an identification guide, just in case.

*Our family enjoys ‘Bug Bingo‘ and would recommend it, particularly if you have budding entomologists in your house. Easy enough for younger ones to play and enjoyable enough for the whole family together.

Scotland’s Red Squirrels

During spring, red squirrels are focussed on producing and nurturing young. The benefits to us are that there are numerous observable behaviours that can hint that the red squirrels in your area are breeding, even if catching a glimpse of the tiny kits themselves proves difficult. To find out more about red squirrel breeding behaviours, read my article on the Saving Scotland’s Red Squirrels blog.


A red squirrel feeding at RSPB Loch Leven earlier this year

Red Squirrels have been declining in Scotland for decades. This native species has struggled with disease and competition from grey squirrels (a non-native species, introduced in the late 1800s) resulting in a vastly diminished red squirrel population. Scotland is home to around 75% of the UK red squirrels, and the Saving Scotland’s Red Squirrels project aims to bolster, conserve and increase the numbers of this iconic species.

There has been some encouraging news for Scotland’s reds recently.  Population decline has slowed and project showed that the numbers in 2017 remained stable. If you spot any red or grey squirrels you can report your sightings which will support this important red squirrel conservation work.

Threats to Amphibians; Part 1: Ranaviruses

The Northern hemisphere is currently in the midst of spring, the season I have associated with frogspawn and tadpoles since I was a very young child. These days, I still experience child-like excitement when spotting amphibians in the wild, but there are ongoing challenges which must be overcome if amphibians are to thrive.

Common frog – the species most frequently affected by ranavirus in the UK

There are several factors threatening the existence of amphibians including pollution, loss of habitat, international trade in amphibian species, climate change as well as infectious diseases. Ranaviruses are some of the infectious pathogens contributing to dramatic loss of biodiversity of amphibian species.

Ranaviruses are emerging pathogens which have caused significant losses to amphibian species worldwide. Ranavirus is of such a concern that the World Organisation for Animal Health (OIE) have placed it on a list of notifiable pathogens. (Schloegel et al., 2010) This article will concentrate on the situation in the UK.

The UK boasts only two native frog species (common frog and pool frog), two native toad species (common toad and natterjack toad), and three newt species (Palmate, Smooth and Great Crested). Threats to any UK amphibian could be devastating for native wildlife and pond ecosystems. Currently ranavirus has caused the most devastating effects among the UK’s common frog populations (rana temporaria), and has been linked to several mass mortality events in this species.

Ranavirus behaves slightly differently in the UK than in some of the other geographic locations in which it has been studied. Ranavirus usually affects adult frogs in the UK, while in the rest of the world the majority of the effects are observed in the larval forms (tadpoles).

In the UK adult frogs are more commonly affected than tadpoles

In infected individuals, the symptoms are varied. The virus frequently causes ulceration, either of the skin or internally. This may cause obvious wounds on the skin, or even missing digits, which can become secondarily infected by other pathogens. Cutaneous erythema (redness) may be visible, with swollen limbs, unusual swimming patterns and lethargy also observed. On post-mortem, haemorrhages are often discovered within the internal organs. The clinical signs are therefore non-specific and the overall appearance of infected frogs may be augmented by concurrent pathogens or pathologies of other origin.

Ranavirus first was observed in the UK in the1990s after several mass die off events in England. (Cunningham et al 1996) Continued study of those outbreaks and tissues archived at that time has revealed two ranavirus lineages detected in UK amphibians. These are termed CMTV-like (common midwife toad virus-like) and FV3-like (frog virus 3-like). The genetic data has shown that it is likely that FV3 in particular has been introduced to the UK at several times and different locations, although the exact routes and methods are unknown. (Price et al., 2017)

More work is required to fully elucidate the epidemiology of the viruses to clarify the host range and indicate any as yet unidentified species which may be involved in virus transmission. Ranaviruses are not species specific and have been detected in a variety of different species worldwide including fish, reptiles and various amphibian species. In the UK, ranavirus has also been detected in common toads and newts.

Although it may be possible to find an isolated affected frog, the primary indication of Ranavirus infection is mass die-offs in a population of frogs. Numerous individuals may be affected and perish within a short period of time. In the UK infections and mass die-off events were first reported in the late summer months, in South-East England. Since then positive virus samples have been identified in the West and North of England as well as in Wales and Scotland.

Three main outcomes for a population follow from infection. Firstly a transient pattern of infection may be observed, where after a period of pathology and mortality, there are no subsequent deaths. Secondly, catastrophic die-offs have been observed in some habitats where ranavirus kills all the frogs in that location. Finally, a persistent infection pattern has been noted. An initial infection period causes morbidity and mortalities in a population then among the remaining frogs, further mortalities are observed in subsequent years. These outcomes are without exception catastrophic for frog populations, which may not recover. (Teacher et al., 2010)

There is some evidence however that the frogs may mount adaptive immune responses to ranavirus. Behavioural adaptations have also been observed, where it was shown to be more likely that uninfected frogs would mate with each other. (Price et al., 2015; Teacher et al., 2009) So although much more needs to be known about ranaviruses to protect UK amphibians, and potentially other species too, there does appear to be indications that wild frogs are adapting to the presence of ranaviruses.

Everyone can play a role in preventing the spread of infectious amphibian diseases. If you spot healthy, normal amphibians sightings can be reported using the dragon finder app, which is part of the frog life group, which is focussed on conservation and education. Your sightings can inform future conservation efforts and research. Diseased amphibians or mass die off events should also be reported, this time via the Garden Wildlife Heath project. Finally, remember not to move any amphibians or spawn between ponds, to prevent spread of infection.

To prevent spread of infection, don’t move any spawn that you may find.



Cunningham AA, Langton TES, Bennett PM, Lewin JF, Drury SEN, Gough RE, et al. (1996) Pathological and microbiological findings from incidents of unusual mortality of the common frog (Rana temporaria). Philos Trans R Soc Lond Ser B-Biol Sci. 351: 1539–1557. pmid:8962441

Price, S. J., Garner, T. W. J., Balloux, F., Ruis, C., Paszkiewicz, K. H., Moore, K., & Griffiths, A. G. F. (2015). A de novo Assembly of the Common Frog (Rana temporaria) Transcriptome and Comparison of Transcription Following Exposure to Ranavirus and Batrachochytrium dendrobatidis. PLoS ONE, 10(6), e0130500. http://doi.org/10.1371/journal.pone.0130500

Price SJ, Wadia A, Wright ON, Leung WTM, Cunningham AA, Lawson B (2017) Screening of a long-term sample set reveals two Ranavirus lineages in British herpetofauna. PLoS ONE 12(9): e0184768. https://doi.org/10.1371/journal.pone.0184768

Schloegel LM, Daszak P, Cunningham AA, Speare R, Hill B. (2010) Two amphibian diseases, chytridiomycosis and ranaviral disease, are now globally notifiable to the World Organization for Animal Health (OIE): an assessment. Dis Aquat Organ. 92: 101–108. pmid:21268971

Teacher, A. G. F., Garner, T. W. J., & Nichols, R. A. (2009). Evidence for Directional Selection at a Novel Major Histocompatibility Class I Marker in Wild Common Frogs (Rana temporaria) Exposed to a Viral Pathogen (Ranavirus). PLoS ONE, 4(2), e4616. http://doi.org/10.1371/journal.pone.0004616

Teacher, A.G.F., Cunningham, A.A. and Garner, T.W.J. (2010). Assessing the long-term impact of Ranavirus infection in wild common frog populations. Animal Conservation 13, 514-522.

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