nest – Grantham Ecology

Thermal Imaging footage of Honeybees and Bumblebees

December 7, 2018December 7, 2018Grantham Ecology2 Comments

Thermal imaging technology works by recording the infra-red energy emitted from surfaces – this doesn’t rely on a light source like typical infra-red photography, but instead measures the radiation given off by both living an inanimate objects. The camera can measure the temperature of these items and display a ‘thermal’ image which shows the gradation and variation between different objects within the field of view. In simple terms – it can show a hot object as white/red whilst cooler objects would be shown as green or blue.

In mid-summer, social bees produce a high density of very busy insects in the nest, so it was no surprise that they stand out a mile on a thermal camera! It was also exciting to be able to understand what individual bees had been doing – for example their temperature signature differentiated those who had recently returned to the nest from those who were standing guard and checking in new arrivals.

Wild Honey Bee Nest

We often encounter honey bees when out looking for tree roosting bats in woodland and this was a prime example! Whilst honey bees are often kept in hives, they can establish wild colonies in features such as this.

Showing the tree cavity feature where the honey bee nest was located

I took the following images around sunset so the tree itself was cooling but you can immediately see just how hot the inside of this tree cavity is compared with the surrounding wood. The temperature reading inside the nest was 33 degrees Celsius, whilst the surrounding tree barn dropped to around 25 degrees.

FLIR0203 — A still photograph of the bees within the nest – you can see the differential in heat between the nest itself (yellow) and the outer wood (black). You can also see a recently-returned bee glowing white hot!

Even at sunset, honey bee workers were still returning to the nest and you can see the white-hot glow of these warmer bees compared with the much cooler bees at the entrance. What is also interesting is the pattern of heat in these recently-flown bees – the flight muscles are in the thorax where the wings are attached and this part is much hotter than the abdomen as you can see more clearly in the video below.

The thermal image gave a nice opportunity to watch guard behaviour in action – some honey bees will take the roll of guarding the nest entrance, positioning themselves on the edge and checking returning bees to ensure that they are welcome. The thermal footage clearly differentiates those bees who have recently flown from those which have not, and you can see the much cooler guard bees intercepting the warmer returning workers as they pass by.

If you’re interested in guard behaviour, you might also like this post from a couple of years ago regarding this behaviour in hornets!

Bumblebee Nest

These images and videos come from a bumblebee nest which was situated underneath a loose cobble in the courtyard of our office.

Bumble Nest — The stone beneath which the bumblebee nest is situated

I think the bumblebees are either white-tailed (Bombus lucorum) or buff-tailed (Bombus terrestris) bumblebees – this photo shows one of the worker bees returning with well laden pollen baskets.

Bumblebee worker returning to the nest with well-laden pollen baskets.

The thing that I found most surprising on the thermal footage to see just how hot this cobble got compared with those around it, even though the nest is buried beneath! I assume this is due to the heat rising with the warm air from the next and heating the stone as it passed by.

As with the honey bees, you can see how much warmer the active bumblebees are compared with their environment. Bumblebees have a good degree of control over their temperature. The hairs on their body provide some insulation and they can use their flight muscles – uncoupled temporarily from their wings – to warm themselves up before taking off. This uses the same technique as they use for buzz-pollination of some flowers. This video gives an idea of just how much heat these muscles can generate, allowing some bumblebees to remain active through the winter, flying at temperatures of just 10 degrees Celcius. You can read more about bumblebee thermoregulation here!

2017 in Invertebrates

December 30, 2017Grantham Ecology4 Comments

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!

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.

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.

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!

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!

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.

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.

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.

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.

2017 in Bees

December 27, 2017December 29, 2017Grantham Ecology6 Comments

If trees are the elders of the countryside, then the bees are part of the summer pageantry of a fairground, here in numbers for just six months of the year they work hard and play hard, getting drunk on nectar whilst setting themselves up for the long winter ahead.

I love to look back on photos from the year and see the changes in light and colour as well as species – hopefully this will come across in the retrospective below:

Honey bee – Apies mellifera

The first bees of the year for me, appeared on valentines day a whole month before I saw the next. These were the honey bees on the gorse flowers, just a stones throw from the edge of the residential in Grantham. I would expect these were from a hive somewhere in a garden nearby. The footpath here winds through the gorse shrubs, creating a sheltered microclimate filled with the coconut-scent of the flowers making an ideal first-forage of the season!

Early Mining Bee – Andrena haemmorhora (male)

This beautiful little bee is the first mining bee I saw in 2017. This was taken at Farndon Willow Holt – a Nottinghamshire Wildlife Trust reserve which is best known for its collection of willows but with many other habitats besides. This little male mining bee was on a blackthorn flower against the blue spring sky in March.

Early bumblebee – Bombus pratorum

This is the aptly named ‘early’ bumblebee – visiting winter-flowering honeysuckle in my parents’ garden back in March. Ornamental and garden plants such as this can really extend the range of nectar sources available for early-flying bumbleebee queens in the springtime.

Ashy mining bee – Andrena cineraria

This little bee appeared on the inside of our new greenhouse as we were assembling it over easter. The structure was only half-glazed at this point and upon flying in, it must have flown upwards and become trapped in the glass roof. After a few photos, I sent it on its way! These grey and black mining bees are very striking, and often the first ‘unusual’ bees which people notice in their gardens before discovering the world of different bees which their flowers support.

Early Mining Bee – Andrena haemmorhoa (female)

This was one of the first mining bees I ever took real notice of – it was searching for its hole next to me in the garden and I was struck my the beautiful patterning of the fur. This shot was taken in a spot I came to think of as ‘bee alley’ – just around the corner from work it has a good patch of green alkanet – an early flowering member of the forget-me-not family – and the aspect catches the sun at lunchtime resulting in a new species pretty much every day I visited! Read more about the bees I saw there on this page.

Bumblebees along The Drift

The Drift is an ancient track which runs along the Lincolnshire/Leicestershire county boundary near us. The limestone grassland is filled with wildflowers but the key species for bumblebees is always the viper’s bugloss – it produces nectar-rich flowers which are accessible to a range of the ‘generalist’ bumblebees and will keep on producing more week after week. If you want to boost the bee-value of your garden – this would be my top tip!

Tree Bumblebees (Bombus hypnorum) Mating

The house next door to us had a tree bumblebee nest this year and one day, the garden was filled with the tandem flights of newly emerged queens and sharp-eyed males who had latched on to mate with them. It was amazing to watch the queens successfully take off with such an extra weight on their backs! You can see in this photograph how much smaller the male bumblebees are compared with the queens.

Tree Bumblebee (Bombus hypnorum) Nest

This was a photo of a tree bumblebee arriving into its nest in a fallen willow. The nest was in a failed hazard beam meaning the cavity opened on both sides with the nest situated in the cavity above. By positioning myself on the opposite side, I managed to get this shot of a worker approaching and about to enter the nest.

Black Ruderal Bumblebee – Bombus ruderatus

This was another photograph taken along The Drift – this time of a bumblebee which had spent the night on a knapweed flower and had not yet warmed and woken up. This was one of several individuals which were all black – a melanic version of the ruderal bumblebee which is typically banded. This species of bumblebee is thought to be on the increase – possible reasons could include climate change or the increased planting of red clover.

Leafcutter Bee (Megachile versicolor)

I had made a bee hotel way back in April and this was my favourite resident – a leafcutter bee (probably brown-footed leafcutter) which would spend its days bringing sections of leaf back to seal up egg cells within its nest tubes.

Male Bumblebee (species… forgotten!)

This photo was taken after a summer rain shower – this male bumblebee had been caught out on the verbena in the garden and was waiting to dry out. You can see the characteristic ‘yellow moustache’ which typically is found on the males of the commoner species including Bombus lucorum, B. lapidarius, B. pascuorum, B. jonellus and B. praetorum

Carder Bumblebee (Bombus pascuorum) on Carline Thistle

I liked the colour scheme of this shot – the carline thistle (in full flower despite the appearances!) and the carder bumblebee share the same straw-coloured brown which seemed characteristic of the countryside in late summer. This photograph was taken at Harbury Spoil Banks – a Warwickshire Wildlife Trust reserve.

Solitary Bee on creeping thistle

I’m afraid my ID skills aren’t up to this one, but this is one of the small solitary species resting in August. I like the way the thistle flower looks similar to an anemone, reminding me of the clown fish and sea anemone relationship. This little bee was actually blowing bubbles into the wind when I found it – a behaviour thought to be useful in reducing the water content of the nectar and increasing its concentration.

Heath bumblebee – Bombus jonellus

This was a male heath bumblebee on the heather at Curbar Edge taken just before sunset. This was one of the last bees I saw in 2017, and the first time I have seen this species which is common in heathland areas but can also be found in parks and gardens near to the habitats. I liked the way this one posed at the top of the strand – actually he was trying to be lazy and reach the next flower without taking to the wing!

Hornet Sentries

November 21, 2016Grantham Ecology2 Comments

I was intrigued to spot the nest of an European hornet – Vespa crabro – in an old haybale at a survey site recently. It was the middle of October and the weather was turning cooler and damper.

I was fascinated by the behaviour of the guards who were stationed at the entrance where hornets returning to the nest would land and enter. One individual was stationed to intercept each new arrival, touching antennae with them before either letting them pass or subjecting them to further scrutiny.

A hornet sentry stationed at the entrance to a nest built into an old hay bale

I can find little on this behaviour in hornets, but as a social hymenoptera, I hope that honeybees are a good parallel. The seminal piece on guard behaviour seems to be Butler and Free’s 1952 paper entitled The Behaviour of Worker Honeybees at the Hive Entrance.

In honeybees, the guards are drawn primarily from younger bees with older workers rarely taking the role. The role of guard is also not fixed – many also forage and will even be seen attempting to rob the nests of other hives. If the hornet system is the same, this would mean that one of many workers can take the sentry role.

In the paper, the Guard Bees are described as ‘assuming a very typical attitude, frequently standing with their forelegs off the ground, with their antennae held forwards and their mandibles and wings closed. Should they become even more excited they open their mandibles and wings and appear to be all ready to rush towards any intruder. Such excited guard bees watch the movements of bees flying overhead and approaching the hive, often jerking round to do so, and make intention movements to intercept any bee which they see to alight near them‘. This very neatly describes the behaviour I was watching, and is shown in the photograph below of the guard intercepting a new arrival.

The hornet sentry waiting to interrogate a new arrival on their return to the nest

The method of interrogation was through contact between the antennae of the two hornets – social hymenoptera have an advanced ability to distinguish between those within their colony and those outside – termed ‘kin recognition’. Some individuals returning to the nest showed almost no signs of interest in the guard and simply barged on in whilst others paused and interacted with the guard before being allowed entry.

The guard did their best to check their credentials and usually found them acceptable, but sometimes would follow a returning hornet into the entrance for further investigation.

Showing the guard hornet interrogating their nestmate

One or two individual hornets were not permitted entry, despite repeated attempts to gain it. They would be chased away across the face of the haybale by the guard, soon to return and re-attempt entry only to be denied once more. There may be several reasons for this. These rogue hornets could be individuals from another nest, or it could be that the guard was mistaken in denying entry to a member of their own colony. The system relies upon chemical signals, and is not perfect leading to errors through denying entry to legitimate colony members as well as sometimes accidentally allowing entry to non-nestmates.

The investigation in honeybees noted that intruders carrying a load of pollen were usually permitted entry whilst those without were more likely to be intercepted and turned away. This is perhaps on the assumption that robbers rarely come bearing gifts and so their arrival with resource suggests they can be allowed in. Other factors important in influencing guard behaviour was recent disturbance – if the nest was disturbed and the bees felt under threat, they were much more likely to examine newcomers, even those with a full load of pollen.

This is a fascinating fascet of behaviour and I have tried to piece together the likely story based on the research into the honey bee. If anybody can provide me with further information about this behaviour in hornets, I would love to hear from you!

Juvenile blackbird practising nest building?

Video June 4, 2014Grantham Ecology2 Comments

I left a trailcam recording a blackbird nest after the chicks had fledged, hoping they might return to have a second brood. The parent blackbirds have subsequently set up a new nest elsewhere in the garden for a second brood but I have a few clips of this juvenile blackbird apparently practising repairing/building the abandoned nest it was born in – after these clips it wasn’t recorded at the nest again for the following week and no further use of the nest has occurred so far. I thought this was rather interesting behaviour – it reminded me of a child playing with a doll’s house as though it was practising for when it was grown up! Any thoughts or observations on this behaviour would be welcomed!