From Asia with devastation

Hawaii was first to be invaded in the shadow of the Cold War, in the 1980s. Just under a couple of decades later, an attack was launched upon mainland USA. The first troops made landfall in 2008, in California. Over the next two years the front line progressed eastwards and now the whole of the USA is enemy territory. Meanwhile a stealthy attack was being launched on Europe, with many Western countries such as Italy, France, Belgium and Spain besieged. Six years ago, in 2012, the UK fell under fire. Drosophila suzukii had arrived from South-east Asia, with consequences.

The genus Drosophila is massive, with around 1,500 species described. One species, Drosophila melanogaster, is famous for its use in genetics and developmental biology experiments; they are “lab flies”. When one uses the phrase “fruit flies”, one is usually referring to this genus. Despite their frugivorous (fruit-eating) habits, they are, on the whole, fairly harmless to the fruit industry. This is because the vast majority of them lay their eggs in rotting fruit, while fruit pickers obviously tend to choose fruits that are ripe or not yet ripe. Therefore, Drosophila species have no impact on fruits prior to harvesting. Except for Drosophila suzukii, that is.

Drosophila suzukii has one minor difference in its lifecycle that has earned it the infamy of being one of North America’s most prolific crop pests. The females possess on their ovipositor (from which the eggs are laid) a serrated knife-like structure which can slice through the skins of fruits like cherries and blueberries. This allows the species to thrive in and damage fruits prior to harvest, while other species have to wait until decomposition has rendered the fruits soft enough to lay eggs in without relying on cutting into them.

Finding this species in my very own garden really drove this worldwide colonisation home (almost literally). It is amazing to think that, having lived in the same house for my entire life, if I’d hung some banana slices from our plum tree – like I did last week – up until I was nine in 2012, I probably wouldn’t have found this prolific invader. Yet, sometime between then and now, Drosophila suzukii has winged its way into our village and begun to breed. Below is an image of the tiny fly, around 2.5 mm in length, which has hitched a series of lifts aboard ships and other vehicles around the world from its native home in South-east Asia to appear at my doorstep. Little does it know about the billions of dollars of crop damage its species has caused along the way.

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The male of Drosophila suzukii is distinguished by the black spots near the apex of the wings

 

 

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Thick-headed

At the end of March I had the good fortune to be able to visit North-east India for a few weeks. For the first part of our trip, we stayed at the Sunderban Jungle Camp on the edge of the Indian Sunderban Tiger Reserve. Each day we would take a boat and explore the unique habitat of the mangroves and hope to find some of the special species that inhabit it.

Luckily we had several great sightings of restricted-range birds in particular, such as Brown-winged Kingfisher. This species is restricted to the mangroves on the coast of the Bay of Bengal and the Andaman Sea from Odisha to the southern tip of Myanmar. It was one of six Kingfisher species encountered in the Sunderbans, surely the Kingfisher capital of the Indian subcontinent.

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Brown-winged Kingfisher

Although my personal highlight was not the intricate beauty and variety of the many kingfishers seen, but the drab Grey Thickhead. Unsurprisingly this is not the modern accepted vernacular name for this species, although it is the literal translation of the Mangrove Whistler’s scientific name, Pachycephala cinerea. Although is is unclear to me what warranted their scientific name, the genus appears to me to be just like typical flycatchers albeit with a slightly broader bill and perhaps chunkier. However it is not the appearance that drew me to this species, but the melodic song.

The voice of the Mangrove Whistler rises high and proud above the accompanying chorus of the mangroves. It consists of a series of tuneful notes which crescendo to a concluding flourish which is audible even above the din of the motorboat as it chugs along down the wide mangrove channels.

Having heard the distinctive tune, our guide Sujan ordered our boat to be stopped at the edge of the mangroves near where the whistler was whistling. To him it sounded abnormally close, the species usually prefers to remain deep within the mangrove forest without access by boat. This is why they are very tricky to see in the Sunderbans: walking is forbidden due to the danger of tigers. So when I caught a movement out of the corner of my eye, I knew that I was very privileged.

The small nondescript bird flew up to a convenient perch on one of the higher mangrove bushes along the river. From there it began to sing, occasionally switching position but almost constantly in view for several minutes. So hard to find, so unexpected that this species wasn’t even on our trip checklist – a cumulative list from around 9 years of running this trip with 2 or 3 trips a year. Our guide has the honour of having seen over 1100 species of birds in India, yet the elusive thickhead only 5 or 6 times before.

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The Mangrove Whistler sitting dignified on its mangrove perch

It’s Popping Hot

Some people find plants boring. However, they are very clever. How can a plant be clever? Through evolution, plants have developed many fascinating ways to survive and thrive.

The key to a plant’s success is largely in the seed dispersal technique. Without a way to disperse seeds, plants would not be able to colonise new suitable habitat and spread. Therefore plants have learnt to be ingenious in their methods of ensuring the future of generations to come.

Yesterday afternoon I was walking through my local farm when I heard a few pops coming from the vegetation beside the path. At first I thought they were the calls of a grasshopper or a cricket, but definitely not a species I had heard before. I stopped and waited to see if I could hear anymore. I did, and this time I thought they sounded like click beetles, but why would so many be clicking at the same time? I was puzzled by this strange sound until, accompanied by a pop, I saw a quick movement out of the corner of my eye. I looked closer to where the movement had come from but I couldn’t see anything that I thought could have made the sound, just a patch of vetch. Then I realised that the sound was coming from the vetch itself!

Vetches are plants related to peas, they have pods like peas although usually much smaller. The pods begin green, the same colour as the leaves, and then as they mature they turn darker until they are brown. Plants in the pea family often have pods that pop, which is advantageous to the plant as it is a great method of seed dispersal. This method ensures the seed is enough distance away from the parent plant to prevent overcrowding.

Before I witnessed the popping of the seed pods yesterday I had no idea how it actually worked. How did the pods pop? I have done a bit of research and what I found out was fascinating. On hot days like yesterday the seed pods dry out, aided by the dark colour of the mature pods in some species which absorb heat. During the drying process forces build up inside the pod until it reaches a point when the pod explodes. In most pods there are two lines of weakness running along the pod, and it is here where the tensions which are set up in the wall of the pod cause the pod to explode. Similar to when a pulled spring is let back, the two halves of the pod curl back at lightning speed which flicks the seeds out of the pod!

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These two pods are still green and have not dried enough to pop.

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Two seed pods which are ready to pop! They have dried in the hot weather and turned brown.

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Two freshly-popped seed pods, showing the two halves of the pod

 

Mongolian Dinosaur Bones

This is my first post on bones, I would love to do more but I’m not the luckiest of people with finding skeletons. I once found a freshly dead Robin, but somehow it was stolen under a bucket that was still upright. Unfortunately the bones that I am writing about today were not my find, but my dad’s.

My dad was very fortunate to be able to visit Mongolia on a birding trip while I was still beavering away at school. Understandably I was very jealous. But it wasn’t all birding, he visited the Flaming Cliffs and dug up some dinosaur bone fragments!

Mongolia is well known for its paleontology. The first ever dinosaur eggs were discovered in the Flaming Cliffs site of Mongolia’s Gobi desert. These eggs were discovered in 1923 by paleontologist Roy Chapman Andrews who went on many paleontology expeditions throughout China and Mongolia. Chapman Andrews removed many of his finds from Mongolia. Now of course all bones must be left in situ, so the desert is strewn with small fragments. But there must still be big discoveries waiting to be made.

There are a few ways to tell bones from stones. The easiest method, and the one my Dad used, is that when a dinosaur bone is placed on your tongue, it should stick. It did, surprisingly well!

1 Garden, 24 Hours, 184 species!

…and counting! Last Sunday, the 5th, I took part in the Garden Bioblitz for the first time. The aim of a bioblitz is to record every species you find in an area within a period of time. For the Garden Bioblitz, you record every species you find in your garden during a 24 hour period.

To begin my Garden Bioblitz I looked through the moth trap from the previous night. There was a very wide range of species, including 23 that were new to me. The highlights were:

  • Great Oak Beauty – annual in Domewood, but Nationally Scarce B (NB).
  • Cacao Moth – usually found indoors in stores of products such as nuts, almonds, tobacco and cacao. I’ll be checking my muesli from now on…
  • Scorched Wing – a beautiful moth which is also classed as Local. There were 8 in the trap.
  • Peach Blossom – a great moth with a great name although quite common.
  • Cypress Carpet – quite an uncommon moth, which arrived in Britain through its host plant, cypress. There are lots of Lawson Cypress trees in the garden which probably explains its occurrence here.
  • Diamond-back Moth – for some reason, I rarely see immigrant moths. The Diamond-back Moth is only the third immigrant moth I’ve recorded. I recorded it for the first time during the last weekend of May, but there were 29 in the trap!

I also caught a very interesting beetle that had a very pungent smell. I thought it was a sexton beetle and I was right. However, I wasn’t too sure which species it was. It was all black and luckily there are only two all-black species in the British Isles: Necrodes littoralis (the Shore Sexton Beetle) and Nicrophorus humator (the Black Sexton Beetle). It turned out to be the Shore Sexton Beetle due to the antennal clubs not being brushes as in the Black Sexton Beetle. Thanks to Chris Brooks on iSpot for the identification. Sexton beetles are interesting because they feed on dead animals. If the dead animal is small then they will bury it to keep other scavengers from taking it. They do this by excavating the soil under the body so that the dead animal sinks into the ground. The adults lay eggs nearby and when the larvae hatch they crawl to the dead animal to feed and even be fed by the adult. Even though this beetle was caught in the moth trap there isn’t necessarily a dead animal nearby as they can fly quite long distances in order to find their food.

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After I had finished looking through the moth trap, I walked around the garden listing all the wild plants. Before I added the plants I already had a list of almost 70 and there was still lots to identify! Other non-moth highlights included a Canada Goose flock flying over and the first Grey Heron I have seen fly over the garden in more than a year. After I finished off the plants I had breakfast, meaning that I had a list of 130 before breakfast. Things were going well!

It wasn’t just plants that I added to my list on the walk around the garden. It was quite early but there were still some insects on the wing, including Rose Sawflies, Speckled Wood butterflies, Large White butterflies and various bees. I was even lucky to see the young fox that has been hanging around the garden for the past few weeks. It is not that shy, here is the photo I took when I first spotted it:

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After breakfast I looked under the logs and stumps in my garden. As always, they were brimming with slugs, beetles, woodlice and other creatures. The most common ground beetle was Agonum emarginatum, a species usually associated with damp habitats near freshwater. This makes sense as most of the stumps were near our tiny pond. The list of slug species was quite good too: Budapest Slug, Leopard Slug, Yellow Slug, Dusky Slug, Greenhouse Slug and Ambigolimax nyctelius, the species I found new to Surrey last year. When I first found it I had to send it off to Wales to get the genitalia looked at, but this confirmed the scientist’s suspicions that there were slight morphological differences between Ambigolimax nyctelius and the Greenhouse Slug. In my experience, Ambigolimax nyctelius is more boldly marked than the Greenhouse Slug.

Finally, the highlight of my bioblitz was finding an amazing fly species that I have been looking for in my garden since Tony Davis told me that it was likely to appear here. It’s not rare or scarce, but it is impressive. It is a species of hoverfly that mimics bees. It has many different forms that each mimic different bee species. It’s called the Narcissus Bulb Fly or the Greater Bulb Fly and it’s eggs are laid in bulbs of various species such as garden daffodils. I found a mating pair on a Bulbous Buttercup, perhaps the plant that the eggs were about to be laid in? The male seemed to be an Early Bumblebee mimic:

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However, I’m not sure which species the female was impersonating:

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It seemed to be all black except for the last 4 or 5 abdominal segments, which were off-white.

So, I’m currently on 184 species and hope to identify a few more for my bioblitz list.

 

Some interesting Blackbird behaviour

There has been some drama happening with our Blackbirds this year. Before exactly a month ago, we had a regular pair of Blackbirds that inhabited our garden and regularly visited the space under our feeders. We could tell this pair from the other Blackbirds as both were ringed earlier in the year. They had built a nest in the middle of March, which had 3 eggs in by the time I left on holiday to South Africa. When I returned the eggs should have been at the nestling stage, but the nest was empty.

On the 1st of May I noticed 4 male Blackbirds chasing each other around the garden pursued by a female. They disappeared out of view until a few hours later I spotted a male singing in the tallest Oak that I can see from my bedroom window, which leans over into our garden from our neighbour’s. It wasn’t ringed.

A few days later something I wasn’t expecting appeared below our feeders. A juvenile Blackbird. There was still no sign of the original pair, so this one must have been brought in by the currently dominant pair. But why only one? I think that as this is still quite early in the year, the parents might not have been able to find enough food for all 3 or 4 of their chicks, especially considering the strange weather we have been having. I will keep watching the Blackbirds to see if the ringed pair re-appear.

From what I have researched about Blackbird territories, I think that my garden must be quite a good habitat for them. The RSPB say that they are solitary birds, but “Small feeding and roosting aggregation sometimes form at good sites”. We have around six Blackbirds in our garden throughout the year and more in the winter when migrants from the mainland come in. There currently seem to be 3 pairs and therefore 3 territories in our garden, one in the front garden, one in the front half of our back garden and one at the back of our back garden. The size of these territories seems quite small for Blackbirds, so there must be good concentration of food. Inevitably, there have been squabbles from time to time.

I will continue to watch these Blackbirds. Who knows what interesting behaviour I could see next or will I locate the ringed pair?

 

 

 

 

Searching for Sandstone Bryophytes: Part 1

Today we visited Loder Valley Nature Reserve near Wakehurst Place. It is special not only for its excellent Hazel coppice (great for Dormice) and sandstone outcrops but because it only allows 50 people in per day; but we may have been the only people to brave the mud. This was good because the birds on the Ardingly Reservoir were very anxious and agitated.

I had marked some of the species of moss and liverwort found on sandstone in the South-East in my field guide (Mosses and Liverworts of Britain and Ireland: a Field Guide), which has its first birthday in 8 days. There weren’t many, so that made identification relatively easy. That’s crucial when it is unseasonably hot, you are carrying lots and you forgot to bring a water bottle! Not to mention the field guide weighs a tonne!

To get to the reserve, we had to go through Wakehurst Place. Wakehurst is a garden run by Kew and there are a variety of habitats. There are even a few sandstone outcrops. We passed one on the way to the reserve and we could see quite a lot of species even though it was quite crumbly. As well as the Bank Haircap (Polytrichastrum formosum) and the Swan’s-neck Thyme-moss (Mnium hornum) that can be found pretty much everywhere, I found two new species for me: Pellucid Four-tooth Moss (Tetraphis pellucida) and Stipular Flapwort (Harpanthus scutatus). Also on that outcrop was a Garlic Snail, which I wasn’t expecting. Not a new species but it was stunning with the blue on the ‘head and neck’ being very clear.

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A little further along, we came to a stand of Yews. For a while I’ve been looking for a species of midge: Taxomyia taxi. This might seem a little off-topic, but they create galls on Yew to raise their young in safety. And believe it or not, one tree was covered in the galls! New species #3!

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We still hadn’t reached the reserve when I found two more species new to me. I found a patch of Fork-moss (Dicranum) at the base of a large conifer and tried to identify it. It took longer that the two sandstone species to identify but I managed. It turned out to be Whip Fork-moss (Dicranum flagellare). While I was kneeling on the cushion of soft pine needles, I spotted a small insect crawling along one of the roots of the conifer near the moss. On closer inspection I saw it was a globular springtail. I can’t do these by memory, so I took a few photos to look at when I returned home. Recently someone recommended www.collembola.org so that was my resource. It was easy to find as it seems to be quite common and I had a rough idea of which genus it was thanks to browsing the gallery on the NatureSpot website. New species #5 was Dicyrtoma fusca which is also my 5th ever springtail species identified.

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We eventually reached the reserve. There were a couple of trails to choose from but we seemed to choose the wrong one and we only came across a few sandstone outcrops. We did manage to find two new species though, Scott’s Fork-moss (Dicranum scottianum), our second Dicranum species of the day, and the Forcipated Pincerwort (Cephalozia connivens). There weren’t as many bryophyte species as I hoped there would be, but I shall be following in the British Bryological Society (South-East Branch)’s footsteps and visiting Eridge Rocks on Sunday. According to our county recorder, Tom Ottley, the site is looking at its best for 3 decades so I hope to find lots more species.

The Loder Valley Reserve is situated around one of the two arms of Ardingly Reservoir. Therefore in the absence of sandstone, I could enjoy the birds that were on offer. I failed to see the Willow Tits that supposedly breed in the reserve, but I did see 7 Gadwall, 5 Mandarin Ducks and a Common Gull soaring high above us.