Dear Readers, one of the advantages of being a lover of invertebrates is that, during this hot weather, all manner of creatures have flown into the house. The house flies and green bottles are something of a nuisance, but then there are animals like this tiny bug with its very impressive red and black patterning. I rather think that it looks like an impressive African mask.

This is a Cinnamon bug, or Black and Red Squash Bug (Corizus hyoscyami), also known as a ‘scentless plant bug’ to distinguish it from the more commonly-seen stink or shield bugs. It was a very relaxed creature, allowing me to gently prod it into a glass once I’d taken its portrait, and ambling onto a plant once I’d taken it into the garden. None of that manic buzzing that many insects indulge in when trapped! Historically this insect was found in coastal areas but (and here I feel a bit like a stuck record) it is moving north as our climate changes. It also favours dry environments, which might also help to explain the increase in its range.

The Cinnamon bug belongs to the Rhopalid family, all of which are plant-feeders, though none are thought to be pests. It overwinters as an adult, and new bugs emerge from August to October. What I haven’t found is any convincing reason for the creature to be named after cinnamon. One theory is that it emits a spicy smell if handled, but I’m having trouble squaring that with it belonging to the scentless bug family. Cinnamon comes from the inner bark of various trees, so I’m thinking that this little chap doesn’t have the jaws necessary to feast on it. Who knows? If you have any ideas, let me know. I’m just really impressed with his red and black livery, and easy-going nature. Who knows what other insects will fly in? I shall keep you posted.

Dear Readers, there has been quite a lot of research on the subject of bumblebees and climate change. After all, one look at these large, ‘furry’ insects is enough for me to worry about them buzzing about wearing the equivalent of a mink coat. They are, in fact, adapted for tundra conditions – their large size relative to pollinators like honeybees means that they lose heat more slowly than smaller insects (remember that surface area to volume ratio thing that many of us learned in O-Level biology). The ‘fur’ (actually outgrowths of the abdomen and thorax called setae) helps to insulate the bee against cold temperatures, and the bees also have very large flight muscles, which they can warm up by vibrating them – bumblebees are often the only pollinators in flight on a cold morning, and queens can sometimes be seen foraging as early as January in the UK. They also, unusually for insects, can generate their own body heat – they use enzymes that can break down the sugars found in nectar to help them to warm up. The queen in the photo below was spotted on my birthday, 20th January, earlier this year.

Bumblebees generally have one generation per year. In the spring, a queen bumblebee comes out of hibernation, and sets off to find a spot for her nest – you will often see large bumblebees flying low over the grass as if looking for something. A mousehole, dense ivy or a gap under a shed are all desirable spots. Once in her nest, the queen lays her first few eggs, and feeds them all by herself until they hatch as workers and are able to forage themselves. Eventually, there are enough workers for the queen to concentrate on laying her eggs. The colony will comprise less than 1000 individuals, and towards the end of summer the queen will start to lay eggs that will develop into fertile queens, and males. These will leave the nest and mate. The queens, already pregnant, will find a space to hibernate, and the males, the original queen and the rest of the workers will die.

So, bumblebees are basically big and hairy in order to survive in cold climates. How, then, are they doing in the heat?

It’s true that there are bumblebees in tropical and sub-tropical habitats, but these are mostly found at high altitude, where it’s colder, and  they tend to be smaller, meaning that they can lose heat more easily. However, the bumblebee species found in southern Europe and the southern USA are thought to be pretty much at the edge of their range, and are expected to disappear as the summers get hotter and drier, and the winters milder.

For bumblebees in the UK the effects of climate change will depend on the rapidity of change, and intensity of individual events. At over 37 degrees Centigrade, bumblebees forage much less effectively. Queens have something called heat stress proteins, which can protect them against extremes of temperature while they’re hibernating, but workers and males do not have these proteins, as far as we can tell. Bumblebees are also prone to water-stress (desiccation) – one thing that I did during the extreme heat of the past few days/weeks was put out a dish almost full of gravel, and then topped up with water so that insects could land safely and drink.

Bumblebees are tough, adaptable creatures ( I often think of them as the Einsteins of the insect world) and they have a number of behaviours that help during extreme weather conditions. Bumblebee nests are tiny compared to those of honeybees (under a thousand individuals as opposed to tens of thousands), but the workers will club together to  vibrate their wings to try to keep the temperature between 28 and 32 degrees Centigrade. They will also change their foraging behaviour during hot spells, going out in the early morning and later in the day to avoid the heat of midday. Bumblebees also seem to be choosing more isolated, cooler spots in order to make their nests.

However, finding those cooler, more isolated spots is clearly becoming more problematic due to a combination of our habit of paving over our gardens,  using fake grass ( a particular bugbear of mine), agricultural intensification, deforestation and urbanisation. Some bees are migrating to try to find better habitat, and others are seeking spots at higher altitudes, as are many other animals and plants that are adapted to colder conditions. One important  question is ‘what happens when the temperature in mountainous habitats also rises?’

So, how are the bees coping so far? One interesting adaptation seems to be that some buff-tailed bumblebee colonies are surviving through the winter in the UK – presumably people are planting enough winter-flowering honeysuckle and mahonia to enable the colony to survive on iron rations until the spring comes. This may be preferable in some circumstances to a situation where a hibernating queen keeps waking up during the winter and hence burns through the fat reserves that would normally be used to produce her first few eggs. However, a non-hibernating queen will also produce fewer workers, so it may be a trade-off against different conditions.

Climate change is also affecting the delicate balance between the different stages of the bumblebee life cycle and the emergence of the flowers that they rely on – it’s clear that plants are flowering earlier than they used to, which may favour colonies that keep going through the winter, and fortunately many species of bumblebee in the UK can feed on a variety of different kinds of plants, so they will not be as affected as some of the bee species which are more specific in their requirements.

The bottom line is that bumblebees probably can adapt to the higher temperatures of climate change, but only up to a point, and only if there is enough genetic diversity for those adaptive factors to be present in the community of bees. Like animals trapped on islands, bumblebees are increasingly isolated from one another, trapped in small areas of botanical plenty while surrounded by deserts of concrete and agricultural monoculture. The idea of ‘pollinator pathways’, whereby bees of all kinds can forage more widely and can meet and mate with bees that they wouldn’t otherwise meet, is an important one, and it depends on everything from the planting of bee-friendly street trees to putting a pot of lavender or rosemary on the balcony. Will it be enough? Only time will tell.

Common carder bumblebee on bittersweet

This piece is largely taken from ‘Bumblebee resilience to climate change, through plastic and adaptive responses’ by Maebe et al, published in June 2021. The abstract is available here though it looks as if you might need access to a university library (or $15) to read the whole thing. Shout if there’s anything that you want me to look at in more detail – this is a meaty piece of work, and I have tried to precis it. 

I also found this article interesting, especially on the subject of  bee body size and mountainous habitats. 

Fencepost jumping spider (Marpissa muscosa)

Dear Readers, I was talking to my friend J about tattoos at lunch today. At the age of 60 she is planning on getting one in the shape of a swift, and so the conversation turned to what I would have, in the event that I decide to be artistically punctured with lots of small needles.

“A jumping spider”, I said, without any hesitation. And therein hangs a tale.

When I was six or seven, I was out in our tiny garden as usual. I had spotted a tiny creature on the concrete slab that housed the giant post for our washing line, and I had noticed that it was acting very strangely, so I lay on my stomach (in my best party dress as we were supposed to be going out) and realised that the animal was a spider about the size of my fingernail. A few inches away on the slab, a house fly was cleaning its eyes with its hairy front legs, rotating its whole head by about 240 degrees like they do. The spider was prowling ever closer, using the lumps and bumps in the surface of the concrete as cover. Then, it paddled its legs, tensed itself and leapt through the air onto the back of the fly.

And in that moment was Bugwoman born. Because I don’t think I had ever seen anything quite so thrilling or so unexpected, and it opened my eyes to a whole world of astonishment and good old-fashioned awe.

Back to the present day, and I was getting some cushions for the chairs in the garden out of the cupboard when I noticed this little chap. And I am quite sure he was a chap because those ‘boxing gloves’ are pedipalps, which he uses to insert his sperm into a female spider if she is willing to accept him, though my lovely friends at the British Spiders Facebook Page tell me that this is just a young male, as in adults those pedipalps would be more formed, and his stripes would be more defined.

Jumping spiders don’t use webs or any of that namby-pamby stuff – though they will anchor themselves to the ground with a silk line before they spring, just in case the jump fails. They are hunters through and through, and so they have those astonishingly large eyes at the front of their faces which help them to judge distance. The slightly smaller eyes which are further back are used to detect motion.

Most invertebrates, including most spiders, seem broadly oblivious to human presence, moving away when they sense a shadow or hear the vibration of footsteps, but jumping spiders actually look at you. They may even cock their heads like attentive dogs. To me, they are utterly adorable, and much easier to love than some of the bigger, hairier, danglier spiders that you might encounter in a shed. You are not supposed to have favourites, but I confess that these creatures fill me with a warm glow. Here’s a short film of this little chap.

Jumping spiders will also chase a laser pointer in much the same way as cats do. They probably have tetrachromic colour vision (which is better than our colour vision) and they also have high-sensitivity to ultraviolet light. They live in a colourful world, for sure, and in experiments they’ve been shown to be able to learn, remember and recognise particular colours.

Jumping spider chases laser pointer

Although this particular jumping spider is not very brightly coloured, the family to which he belongs (the Salticidae) are extremely varied, with over 6000 species, including the peacock spiders. You may well have come across them before, but if not, have a look at this extraordinary BBC film . Such tiny creatures, with such complex lives! It just reminds me of how little we actually know about the animals and plants that we share the planet with.

And so, I persuaded the jumping spider onto the fencepost for which he is named. Hopefully he’ll find a female jumping spider. At the very least, he’ll be able to find some insects to munch on. Good luck, little chap.

The London Underground Mosquito (Culex pipiens f. molestus)(Photo One)

Dear Readers, I was much taken by an article in New Scientist about the evolution of urban species by Rob Dunn this week, and in particular his thoughts about the infamous London Underground mosquito. During the Second World War, unfortunate civilians who spent nights on the platforms of Underground stations to avoid the Blitz complained about being bitten unmercifully, but it’s only recently that genetic technology has advanced to a point where we can really work out what’s going on.

Sheltering in the Underground (Photo Two)

The original LU Mosquito came from the Fertile Crescent in the Middle East and lived above ground. These insects are active only during the warmer months, require a meal of blood before they can reproduce, and feed mainly on the blood of birds. However, as the mosquito spread north into colder climes, it survived by living in cities, particularly their underground regions such as sewers. The insect evolved new genetic characteristics, such as odour recognition, digestion and immunity, that would be useful in environments rich in organic waste.

However, it wasn’t just the genes that changed, behaviour did too. Both the underground and the above-ground mosquitoes are thought to be the same species, but the underground ones are active all year round, can reproduce without a blood meal, and prefer to feed on mammals: rats and mice in particular, but humans where they can find them. The underground mosquitoes are isolated from other mosquitoes, and their habitat can be compared to an island, as Dunn points out: the mosquitoes cannot disperse, and so they become more and more specialised. Cities such as Paris, Minsk, Tokyo and New York all have their own ‘Underground Mosquitoes’.

However, the isolation can have another, even more extreme, effect – it’s been shown that where LU Mosquito populations are isolated within the Underground network, they can start to become genetically distinct from one another. So, it was found that the mosquitoes found on the Victoria Line were different from those found on the Bakerloo Line. It’s quite possible that every underground line could have its own mosquito, though I suspect that lines with a larger proportion of stations which are above ground might be less distinct, because their mosquitoes can actually disperse and interbreed.

For us, though, as humans, it means that the old Petula Clark song ‘Don’t Sleep in the Subway’ has never been better advice.