2017 in Invertebrates

Bees and butterflies have had a blog post to themselves, but here are a few other invertebrate encounters from 2017 I thought I’d share on the penultimate day of the year!

Wood Ants

These were taken in Great Wood in the Quantock Hills. We spent a while being amazed at the ability of these tiny creatures to pull twigs and other materials into position around their nests, joining others to give assistance where required or simply tugging with amazing tenacity until they got where they were going. Soon we also noticed the guard ants, who were trying their hardest to intimidate us into backing away and leaving the nest in peace!

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Great Diving Beetle – Dytiscus marginalis

We came across this beast when doing great crested newt surveys in the springtime – the bottle traps used to catch and count the courting newts also work for other species such as this, one of our largest beetles. They can have quite a nip, so I’m told, so this one was handled with care before being returned to its pond in a pasture field.

Great diving beetle - Dytiscus marginalis

Sawfly in a buttercup

I came across this little sawfly – its head dusted with pollen – settled in a buttercup flower in Muston Meadows in early summer. It didn’t move as I got into position to take a photo, and I could only assume it had settled there for the night.

Sawfly settled into a buttercup flower to spend the night

Wasp – Gasteruption jaculator

This amazing looking creature was feeding on the fool’s water cress flowering at the edge of our garden pond. The amazing ovipositor is so much larger than the wasp itself which made it look for all the world like a radio-controlled insect as it flew between flowers!

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Wasp – Ectemnius sp.

I came across this little wasp feeding on the hogweed flowers on a walk through Cheddar Gorge and thought it deserved a portrait – the rounded head with the eyes wrapped around looks as though it could have been the inspiration for a number of sci-fi aliens!

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Ornate-tailed digger wasp – Cerceris rybyensis

I was walking through the Hills and Hollows above Grantham one afternoon and came across a series of holes in the bare earth – I watched a while and saw several heads peeking out before one of the insects arrived from outside and I could get a proper view. This is a species of digger wasp whose prey is bees such as this solitary bee held beneath its body. The wasps bring the bees back and pull them underground to provide food for their larvae.

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Darter dragonfly – Sympetrum sp.

This dew-bejewelled dragonfly was resting on a flower stem in Muston Meadows in August. Taken just after sunrise, this shows the roosting behaviour where the dragonflies will find a safe place to spend the night, waiting for the sun to warm them in the morning and get them up to temperature so that they can take to the wing once more.

Snail

This little snail was crawling across the roof of my car when I got back from a dawn bat survey in late summer. I’m not sure how it made its way all the way there, but I liked the reflection in the early morning sunshine. I popped it back into the vegetation in the verge before heading home!

Wolf spider (Lycosidae)

This photograph was taken in the Grantham Hills and Hollows in late summer as the grasses were beginning to turn from greens to browns. I had bent down low to get a photograph of one of the wildflowers, and then my eye was caught by how many invertebrates were active just in the grasses beside it.

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Grasshopper

This grasshopper was taken on the same afternoon as the wolf spider above – I’m afraid I haven’t attempted an ID on this little character but would welcome any suggestions! The camouflage of this grasshopper amongst the greens and browns of the aging summer grassland meant I only spotted it when it hopped to another location.

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Minotaur beetle – Typhaeus typhoeus

This amazing beetle was trundling across a forest path in the Quantocks in autumn. Despite the fearsome looking horns, they are not predatory but are in fact a species of dung beetle which feeds on rabbit droppings amongst others. They nest in deep tunnels and will pull the dung back down with their powerful legs in order to provision the larvae.

 

 

 

 

Victoria: Humpbacks to Hummingbirds

Our final stop on Vancouver Island itself was in Victoria – out on the eastern tip.​

​The highlight of our stay there was the opportunity to see orcas and humpback whales on a trip out into the straights between Victoria and the mountains of the Olympic National Park beyond. We went out on a zodiac and bounced across the waves – not the ideal transport for the seasick ecologist but I soon forgot when we found a pod of orcas moving gracefully through the open seas. The waters around here play host to resident orcas who are present all year round; but this pod was passing through; these are referred to as transient. Interestingly, the two groups have different feeding habits – the resident pods are largely salmon-eaters whilst transient pods tend to eat seals and other marine mammals.

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Members of a transient pod of orcas

After spending 20 minutes watching the orcas, we moved on to watch a pair of humpback whales which were perhaps even more impressive. I know that ‘whales are big’ is about the most basic fact you can learn about them, but I’d never seen one up close before to be able to appreciate just how big they are! They would break the surface to spout at regular intervals of 20-30 seconds and repeat this 5-6 times before arching their backs for a deep dive which results in their tail breaking the surface and following them down to the depths where they would hunt for 5 minutes before returning to the surface for air.

On the way back, we got some great views of the sealions on a small island just off the coast – the smell caught up with you soon afterwards!

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Steller sealions seen on the way back to harbour in Victoria

I had made some assumptions about the ethics of whale watching, in that it must be OK to be sanctioned, but after returning to dty land, I did a little research on the potential impacts upon these species. From the work I do in the UK with bats, I know that a species which relies upon echolocation for navigation and hunting will change their behaviour in response to noise – this is seen through avoidance behaviour or changes in hunting or foraging tactics. It turns out that there is evidence that whale watching can have a similar impact upon whales.

The sites I found which deal with this issue didn’t really give me a satisfactory final answer. Partly this is because these trips occur worldwide, with different regulatory regimes and some wildly different ideas of appropriate practise. And partly because the research simply isn’t there to assess the significance of an impact – the mechanism is understood and an impact demonstrated in some circumstances but the real impact of this growing industry may only become apparent in the long term.

The whale watching tours leaving from Victoria do follow a strict code of practise, and the various boats we saw watching the orcas observed these well. This would significantly reduce the impact in comparison to unregulated tours, but whether it is enough is still questionable. It was an amazing experience, but I would think twice before going out again. The Whale and Dolphin Conservation Society express concerns over trips from Vancouver Island to visit the resident population as, by definition, they are much more likely to suffer from the repeated visits from boats on a daily basis whereas the transient pods are likely to receive much more short-term disturbance.

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Humpback whales spouting off Victoria, BC with the mountains of Olympic Park in the background.

One unexpected reminder of home was walking through the streets at dusk and hearing the trees alive with song. We had watched starlings descending into the city as the day drew to a close and there, in the middle of Government Street amongst the lights and cars, was an evening roost! A free concert for all those who passed by.

The other creature I was really hoping to see was a hummingbird. Victoria gets a number of species through the summer, but their reliance on the seasonal resource of nectar means that most migrate for the winter to seek food. With such a fast wingbeat, their energy expenditure means that they can’t go too long without a sugary refill! We were too late for most, but one exception is Anna’s hummingbird – these have the northernmost year-round range of any hummingbird and are regularly counted in Christmas bird lists for the city. On the last day, I read a tip which suggested listening for the male singing from the top of a tree. I had been sitting a few moments listening to what I assumed was some sort of machinery in the street outside our apartment, before realising that this series of buzzes, chips and whistles was the bird I was hoping to see! Looking for all the world like a pair of outsized bumblebees, a pair were skittering around the top of a street-tree, settling briefly before buzzing onwards and out of sight.

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Anna’s Hummingbird settled in a street tree in Victoria, BC.

The final stop was a few days in Vancouver itself before heading back home – final post coming soon!

Bats hang in the belfry… right?

We were carrying out a building inspection earlier this week, looking into nooks and crannies to see if we could find bats, or evidence of their presence. To reach these features safely, a cherry-picker was hired to lift us into place. The operator was very friendly and interested in what we were doing. When I asked him to take me up to a crevice above a window, he said;

‘You’ll never get a bat in there’

‘You will…’

‘No way… how small are they? I thought they hung up in the rafters?’

The ‘hanging bat’ stereotype is very widespread but really not true of many of bat species in this country. The two horseshoe species will always be found hanging upside-down in the classic pose and some other species will also hang upside down, including the brown long-eared and some of the myotis species. However a number of UK species, including the common pipistrelle – the species you are most likely to see flying in gardens – prefer to roost in crevices where they wedge themselves in quite tightly. Other species falling into the ‘crevice dwelling’ category include the other two pipistrelle species – soprano and Nathusius – the Daubenton’s bat, the larger noctule, serotine and Leisler’s bats, and the rarer woodland dwelling barbastelle bat.

The common pipistrelle bat is often found roosting in crevice-type features in houses, such as beneath lifted hanging tiles or roof tiles, in gaps around windows, in gaps in brickwork or underneath lifted flashing. The gaps they can squeeze into are really very small – 2cm is quite enough for them to get inside.

Last week I was lucky enough to spend a few days climbing trees and inspecting potential roosting features up in Cumbria where we found a common pipistrelle bat roosting in a hollow in a tree limb over a stream. The video quality isn’t fantastic because it is filmed using an endoscope – this invaluable piece of kit is a camera and light mounted on a long flexible ‘snake’ attached to a hand-held screen which you can feed carefully into potential roosting features and look for the bats in places you could never otherwise inspect. Although the quality isn’t great, I think this clip gives a nice insight into the kind of places these bats will choose to roost.

For many more video clips of bats roosting in trees, I would recommend you to check out the Bat Tree Habitat Key page on Facebook.