Bee-flies: the dipteran narwhals

White-tailed bee-fly (Bombyliidae) showing wing venation
White-tailed bee-fly (Bombyliidae), possibly Bombylius posticus, showing wing venation

I always enjoy seeing bombyliids (bee-flies). They sound like little helicopters, hovering and buzzing about, and their furry appearance gives them a certain cuteness. They are flies pretending to be bees!

Not the easiest of insects to identify from photographs though. This one looks rather like Bombylius posticus, which has a wide Palaearctic distribution, but I am not sure if it is found in northern Thailand, where I took the photograph. This species has prominent white tufted scales at both the base and apex of the abdomen. (1). Alternatively, it might be a variant of Bombylius major, which is found in Thailand.

White-tailed bee-fly (Bombyliidae), possibly Bombylius posticus, showing white scales
White-tailed bee-fly (Bombyliidae), possibly Bombylius posticus, showing white scales

Why would they want to mimic bees? One reason might be that they avoid predation by other insects which think that they are bees, i.e. armed with a harmful sting. Although they don’t have a stinging apparatus like a bee, they do have a very prominent, needle-like proboscis sticking out in front of their heads. They use this stiff, unretractable organ to penetrate and probe flowers for nectar. It almost looks like they are carrying a little spear or javelin; the dipteran equivalent of a narwhal! According to Wikipedia, some people in East Anglia call them beewhals. (2)

Bee=fly (Bombyliidae) in flight, showing proboscis sticking out in front
Bee-fly (Bombyliidae) in flight, showing proboscis sticking out in front

Another reason why they might benefit from resembling bees, is that they lay their eggs in the nests of bees and wasps. Indeed, they actually flick their eggs into the nests of some solitary bees, whilst hovering above the nest opening. (See links 3 and 4 for videos of this behaviour). Flicking, or shooting eggs from a safe distance, as one blogger aptly put it! (5) The tufts at the end of the abdomen are reportedly used to collect dust prior to flicking the eggs, something that would be fascinating to watch!

The bee-fly larvae are ectoparasitic, meaning that they attach onto the outside of the bee larvae in order to feed on their body fluids. Perhaps their bee-like appearance helps the adult bee flies get close to bees nests without being attacked? Different species are also parasites, and hyper-parasites, on a wide range of insects, including butterflies, grasshoppers, wasps, other flies, beetles and cockroaches!

White-tailed bee-fly (Bombyliidae) resting.
White-tailed bee-fly (Bombyliidae) resting.

The adults feed on pollen and nectar and are important pollinators, indeed some plants species depend upon them for their survival. There is a nice little blog about bee-flies in a Scottish garden (6).

  1. http://diptera.info/forum/viewthread.php?thread_id=61710
  2. https://en.wikipedia.org/wiki/Bombyliidae
  3. http://www.brc.ac.uk/soldierflies-and-allies/bee-flies
  4. http://abugblog.blogspot.co.uk/2015/04/awesome-bee-flies.html
  5. https://livingwithinsects.wordpress.com/2012/04/22/bee-fly/
  6. http://www.leavesnbloom.com/2012/04/bombylius-major-bee-fly-aerodynamics.html

Termites on a trail

Termites (possibly Hospitalitermes sp), Doi Chiang Dao, Thailand
Termites (possibly Hospitalitermes sp.), Doi Chiang Dao, Thailand

I came across these termites moving along a water pipe on the Gully Trail at Wat Tham Pha Plong, Doi Chiang Dao, northern Thailand. The pipes provide water for the monks and their guests at the temple, but they also provide a convenient thoroughfare for the termites, helping them to move through the forest without having to traverse the ground!

Termites on water pipes, Gully trail, Doi Chiang Dao, Thailand
Termites on water pipes, Gully trail, Doi Chiang Dao, Thailand

These are nasutiform termites, which is to say that the soldiers have a pointed snout – a nasus – and are bit smaller than the workers. Presumably they make up for their lack of stature by being armed with a chemical spray gun, which can shoot a noxious aerosol of glue or repellent at any foe, particularly ants.

Termites (probably Hospitalitermes sp) nasute soldier outlined
Termites (probably Hospitalitermes sp.) nasute soldier outlined

There are at least 92 species of termite (Isoptera) in Thailand, including 7 genera in the subfamily Nasutitermitinae. (1) Most species in this subfamily are found in jungles and forests; they do not usually attack man-made structures, but rather feed on lichen, lichen-bark, dead leaves, branches, twigs, and other plant matter. (2)

I am not certain, but I think these are a species in the genus Hospitalitermes (Holmgren). There are six Hospitalitermes species in Thailand (1) and they forage openly during the day, as here. Other possibilities from northern Thailand are Nasutitermes, Bulbitermes, Aciculitermes and Havilanditermes. Lovely names!

Termites (probably Hospitalitermes sp.), large worker
Termites (probably Hospitalitermes sp.), large workers and slightly smaller, nasutiform soldiers

It is possible that the termites were heading out from their nest to forage in the jungle. I could only find one worker carrying a food-ball in the photos I took (below). Termites are of course decomposers; Nature’s way of cutting up and breaking down wood and vegetation. But they don’t do it alone; they need the help of microbes, symbiotic protozoa which they carry in their guts, to break down cellulose.

Termites (possibly Hospitalitermes sp.). One working (outlined) is carrying a food ball.
Termites (possibly Hospitalitermes sp.). One working (outlined) is carrying a food ball.

What termites lack in size they make up for in numbers. One study of termite abundance in Thailand, found that they were on average 6,450 individual termites per square metre, weighing about 10.7 g. If we scale up this termite biomass, which comprised many species, it gives a total weight of 10.7 million g or 10,700 kg per square kilometre. If I have got my arithmetic right, that is a fantastic ten tonnes per square km! The same as two or three large elephants!

Termites (probably Hospitalitermes sp.) walking along a water pipe
Termites (probably Hospitalitermes sp.) walking along a water pipe
  1. Sornnuwat, Y., Vongkaluang, C., & Takematsu, Y. (2004). A systematic key to termites of Thailand. Kasetsart J (Nat Sci), 38, 349-368.
  2. https://www.termiteweb.com/the-nasutitermitinae-termites/
  3. Inoue, T., Takematsu, Y., Hyodo, F., Sugimoto, A., Yamada, A., Klangkaew, C., … & Abe, T. (2001). The abundance and biomass of subterranean termites (Isoptera) in a dry evergreen forest of northeast Thailand. Sociobiology, 37(1), 41-52.

Stingless bees and resin bugs

Stingless bees (Trigona sp.) emerging from trumpet-shaped nest entrance below dipterocarp tree
Stingless bees (Trigona sp.) emerging from trumpet-shaped nest entrance below dipterocarp tree

The peculiar shape of this nest entrance caught my eye. Bees were moving in and out of the trumpet-shaped nest which was located below a large dipterocarp tree, at the foot of Doi Chiang Dao mountain, north of Chiang Mai, Thailand.

Stingless bees (Trigona sp.) emerging from trumpet-shaped nest entrance
Stingless bees (Trigona sp.) emerging from trumpet-shaped nest entrance

These waxy nests are constructed by stingless bees (Meliponini tribe of the family Apidae), a large group of eusocial insects – meaning they live together in colonies with a queen and have different castes – which play an important role in the pollination of crops and wild flowers in tropical countries. Thirty species of stingless bees in the genus Trigona, have been recorded in Thailand; T. collina is the most common species in the north of the country. (1)

Stingless bees (Trigona sp.) emerging from trumpet-shaped nest entrance
Stingless bees (Trigona sp.) emerging from trumpet-shaped nest entrance

As the name implies, stingless bees lack a functional sting, but they have powerful jaws and will aggressively defend their nests against intruders. Non-foraging bees near the nest entrance are there to protect the nest from a range of insects including parasites – which might try to enter. They also deposit fresh resin on the external entrance tubes, in order to deter ants, which are important predators of the bees. (2)

Stingless bees (Trigona sp.) at nest entrance
Stingless bees (Trigona sp.) at nest entrance

The nests of stingless bees are usually associated with a living tree, either in a cavity in the trunk or at the base of the tree, as in this case. The nest architecture is extremely variable between species, but the shape of the external nest entrance, as well as the internal nest features, are often characteristic of a given species. When nests come under attack, hovering bees emerge in force to defend the colony: they ‘face the nest entrance, and engage in aerial fights with non-nestmates, or directly attack larger animals, which retreat with a cloud of defending bees surrounding the head’ (2).

Stingless bees (Trigona sp.) at nest entrance
Stingless bees (Trigona sp.) at nest entrance

Based on looking at different photographs posted on the Internet, the trumpet-shaped nest opening looks like it might be that of Tetrigona binghami (Schwarz, 1937), also called Trigona apicalis variety binghami Schwarz 1937, although this species was only described for the first time in 2005, in Thailand. (1) Such an identification can only be tentative as there is no definitive key available online that I am aware of. The bee’s nest was located near the base of a huge dipterocarp tree, Dipterocarpus alatus, which was festooned with epiphytes.

Dipterocarpus alatus, Chiang Dao
Dipterocarpus alatus, Chiang Dao

Stingless bees live in colonies of somewhere between a few hundred to several thousand individuals. They usually visit many different types of flowers although some species seem to be fairly host specific. The main host plant of T. binghami is said to be teak (Tectona grandis), whereas T. collina has a number of different host plants, including the large dipterocarp resin tree, Dipterocarpus alatus. (1) These trees often have a sort of scar – a tapping hole or resin trap – in the trunk, not far off the ground, that exudes an oily resin.

Resin trap on dipterocarp tree trunk
Resin trap on dipterocarp tree trunk

The resin has a number of traditional uses, including: wood lacquering, drought-proofing of boats, water-proofing of baskets and traditional medicine.  Tapping involves cutting a hole into the trunk of the tree and using fire to stimulate a continuing flow of resin. Tapping can be sustainable, but it depends upon the skill of the tapper. (4) In sites like this one, in Chiang Dao, where these dipterocarps are the only remnants of a cleared forest, the trees will probably be more susceptible to damage and their loss as a shade would be a severe blow to the resorts and houses which exist underneath their wonderful boughs.

Stingless bees (Trigona sp.) hovering above the resin trap
Stingless bees (Trigona sp.) hovering above the resin trap

Stingless bees are called ‘channarong’ in Thai. Some species, such as T. laeviceps – which commonly occurs in suburban areas – are kept by beekeepers for their honey, which is slightly more watery and acidic than western honeybee honey (3). It also ferments. The process of keeping stingless bees is known as meliponiculture.

Stingless bees (Trigona sp.) hovering above the resin trap
Stingless bees (Trigona sp.) hovering above the resin trap
Stingless bees foraging in the resin
Stingless bees (Trigona sp.) foraging in the resin
Ants on dipterocarp tree
Ants on dipterocarp tree

Also lurking in and around the resin trap were a number of so-called resin bugs. These carnivorous assassin bugs (Family: Reduviidae; Subfamily: Harpactorinae; Tribe: Ectinoderini) coat their front legs with sticky tree resin and use this to attract and trap insect prey such as the stingless bees; a strategy called sticky trap predation. Some authors have called them living fly-paper (or bee-paper) or bee-assassins (South American genera). They really are quite strange looking insects and move very slowly.

Resin bug (Reduviidae; Harpactorinae; Ectinoderini), Chiang Dao
Resin bug (Reduviidae; Harpactorinae; Ectinoderini), Chiang Dao

There are said to be 20 species in the Ectinoderini tribe of resin bugs: ten Amulius spp.; and ten Ectinoderus spp.. The species shown here is similar in appearance to Amulius malayus but I have not been able to confidently identify it.

Resin bug (Reduviidae; Harpactorinae; Ectinoderini), Chiang Dao
Resin bug (Reduviidae; Harpactorinae; Ectinoderini), Chiang Dao

There were also one or two smaller assassin bugs, the nymphal stages of the resin bugs, which also looked to be efficient predators (below).

Resin bug nymph
Resin bug nymph

There was a very attractive spider located near the top of the resin trap.  This orb spider, Argiope pulchella, builds a web with a zig-zag stabilimentum (below). It has weaved together its web to create a much denser and thicker X-shaped cross. The spider aligns its legs against the X-shaped stabilimentum, two legs against each arm of the cross. This presumably acts to camouflage, or hide the spider whilst it is sitting on the web, and perhaps the X-shape also attract flying insects into the web. The spider moves off the cross when attending to a catch.

Argiope pulchella, builds a web with an X-shaped stabilimentum
Argiope pulchella, builds a web with an X-shaped stabilimentum

There are probably many other insects attracted to the resin trap, including moths and other sap-sucking species.  It is a fascinating little ecosystem, if that is the right word, and once again a system that is ripe with opportunities for further research.

  1. Klakasikorn, A., Wongsiri, S., Deowanish, S., & Duangphakdee, O. (2005). New record of stingless bees (Meliponini: Trigona) in Thailand. Nat Hist J Chulalongkorn Univ, 5, 1-7.
  2. Roubik, D. W. (2006). Stingless bee nesting biology. Apidologie, 37(2), 124.
  3. Chuttong, B., Chanbang, Y., & Burgett, M. (2014). Meliponiculture: Stingless Bee Beekeeping In Thailand. Bee World, 91(2), 41-45.
  4. Ankarfjard, R. (2000). Ïmpacts from tapping oleoresin from dipterocarpus alatus on trees and timber value in LAO PDR. submitted to the Journal of Economic Botany.
  5. Zhang, J., Weirauch, C., Zhang, G., & Forero, D. (2015). Molecular phylogeny of Harpactorinae and Bactrodinae uncovers complex evolution of sticky trap predation in assassin bugs (Heteroptera: Reduviidae). Cladistics.

Pompilid spider killer

Pompilid wasp, Chiang Dao, Thailand
Pompilid wasp, Chiang Dao, Thailand

I came across this magnificent spider wasp (Pompilidae) feeding on nectar from these flowers beside the steps leading up to Wat Tham Pha Plong, Chiang Dao, Thailand. I have come across this pompilid wasp before in northern Thailand (1), but I am still not sure what species it is. With its orange antennae, it looks similar to the Australian orange spider wasp (Cryptocheilus bicolor) (2), but the head is not orange and the abdomen is black. So perhaps it is another Cryptocheilus species, of which there are twenty-four known. One website provides a check-list of pompilid species from Thailand (3), but none of these seem to fit the bill. Other sites, simply caption photos ‘Pompilidae’, so it is not one that can be identified from of the Internet. If there are any pompilid experts out there, I would love to know what it is!

Pompilid wasp, Cjiand Dao.
Pompilid wasp, Chiang Dao.

Adult pompilid wasps feed on nectar, but they hunt and kill spiders to provide a food source for their off-spring. They sting and paralyse spiders and carry them off to a nest burrow, where they deposit an egg on the hapless arachnid. Each offspring has its own spider to gorge on. The wasp larva hatches out and starts feeding on the living, paralyzed spider. The bigger the spider, the more likely it is that the larvae will develop into a female wasp (which are larger than males).

Pompilid wasp, Chiang Dao.
Pompilid wasp, Chiang Dao.

I would think that there is much to learn about these wasps, particularly species which have been little studied. The are nearly all solitary wasps although a few communal, mud-nesting species exist (4). The hunting behaviour of one group of pompilids, the tarantula hawk wasps – which occur in the deserts of the USA – has been studied: “the wasp rushes at the spider, grabs a leg, flips the spider onto its back, and stings it….” The tarantulas can mount a counter attack, but it seems they are at a disadvantage and rarely succeed in killing the attacking wasp. (5) One can only wonder at how long this evolutionary battle between wasps and spiders has played out over geological time.

Pompilid wasp, Chiang Dao, Thailand.
Pompilid wasp, Chiang Dao, Thailand.

Some pompilid wasps are cleptoparasitoids; they steal the spider prey caught by other pompilid species. They wait until the wasp which has caught the spider puts it down and turns its attention to nest making; they then rush in and lay their own egg on the spider. This egg hatches out before the one laid by the wasp which first caught the spider, and the imposter larva eats the host egg before it hatches. (5) Very sneaky!

Some pompilids prey on species such as this orb spider, Argiope pulchella (6). The spider is sitting in the middle of an X-shaped stabilimentum; an elaborate web decoration or feature which it has constructed out of silk (below).

Argiope pulchella orb spider.
Argiope pulchella orb spider.

I don’t know how poisonous the sting of this particular wasp I photographed would be to humans; and I would not like to find out.

Pompilids are not aggressive and are usually relatively docile (unless provoked), but the sting of the closely related Tarantula hawk wasps is reportedly very intense. The pain has been described as: “like an electric wand that hits you, inducing an immediate, excruciating pain that simply shuts down one’s ability to do anything, except, perhaps, scream.” (7)

One has to admire the skill and tenacity of these wasps, which often prey on spiders which are much larger than themselves, and highly venomous. They have evolved a way of exploiting this prey source and presumably play an important role in regulating spider populations.

Butterflies, like this Clipper (Parthenos sylvia) also enjoy feeding on the flowers of this plant.

wp-1487720950037.jpg
Clipper (Parthenos sylvia)
  1. https://rcannon992.com/2013/11/23/a-two-tone-wasp/
  2. http://www.brisbaneinsects.com/brisbane_vespoidwasps/OrangeSpiderWasp2.htm
  3. http://insectoid.info/checklist/pompilidae/thailand/
  4. http://www.usu.edu/pompilidweb/default.htm
  5. O’Neill, K. M. (2001). Solitary wasps: behavior and natural history. Cornell University Press.
  6. https://www.flickr.com/photos/phil_arach/galleries/72157651182275337/
  7. http://www.desertusa.com/insects/tarantula-hawks.html

Sperm whales

Sperm whale (Physeter macrocephalus) tail fluke
Sperm whale (Physeter macrocephalus) tail fluke

There are thought to be about 200,000 sperm whales in the world, but there is considerable uncertainty about the figure, which may be anywhere between  200,000-1,500,000 according to one site (1). The IUCN Red List states that the pre-whaling global population of sperm whales was about 1,100,000, so the number is probably much lower than that, in the hundred’s of thousands (2). It is surprising to me that there are no reliable estimates for this iconic animal. Perhaps it shows how little we still know about our oceans.

I had the good fortune to come across a few of these creatures on a voyage between Bali and Komodo (Indonesia) in October, 2016, on board a little ship called Mermaid I (3).

Mermaid I at anchor
Mermaid I at anchor

There are some phenomenal images of sperm whales on the Internet; just google it and you will see fantastic underwater photographs of these huge whales floating majestically below the surface. They are relatively shy creatures, so how divers get so close I don’t know, perhaps they are less wary of humans in the water, than of ships. Sperm whales live for up to 70 years, perhaps more, and sperm whaling was being carried out by Japan until 1988, so many of them may remember being perused and seeing their companions slaughtered. The Japanese are still killing Antarctic minke whales (4).

The first thing you see, as ever child knows, is the blow or outbreath. The Sperm Whale’s blow-hole is set at an angle on the left-hand side of its head; which causes the blow to shoot to the left (below).

Sperm whale blowing to the left
Sperm whale blowing to the left

It is very exciting when you come across a whale! The first one we saw was on the way to Satonda Island, north of the large island of Surabaya. Our small ship approached slowly so as not the frighten the whale, and we managed to get relatively close, although I was using a long lens (150-600mm).

Sperm whale I (Physeter macrocephalus) on the surface
Sperm whale (Physeter macrocephalus) on the surface

Before we could get much closer however, the whale ‘turned tail’ and started to dive. The average dive apparently lasts for about 35 minutes and is usually ‘only’ down to about 400 m, although they can stay down for an hour or so and reach depths over 1,000 m (1). I guess it depends on what they find down there and whether they start chasing some prey item. Or perhaps they get into protracted fights with giant squids who do not relish being consumed by this giant predator of the depths!

Sperm whale I (Physeter macrocephalus) diving
Sperm whale (Physeter macrocephalus) diving

After this whale had disappeared beneath the waves, we realised that there was a small one still at the surface: probably a calf. Females have a calf about once every five years and they stay together for several years. Perhaps this one was too young to start deep diving? Although it has to learn at some stage, and presumably gets lessons from the mother?

Sperm whale (Physeter macrocephalus) calf at the surface
Sperm whale (Physeter macrocephalus) calf at the surface

The next sperm whale we came across was in the open ocean south of the Komodo national park waters. Once again there was the tell-tail blow in the distance. Once again the ship slowed and approached the whale gradually, hoping it would not get spooked and dive down before we could see it.

Sperm whale (Physeter macrocephalus) blowing at surface
Sperm whale (Physeter macrocephalus) blowing at surface
Sperm whale (Physeter macrocephalus) at surface
Sperm whale (Physeter macrocephalus) at surface

This whale was a little bit more co-operative and we managed to get slightly nearer than the first one, but it too soon decided that enough was enough, and it dived down. Being behind it this time, we got a better view of the great tail fluke as it turned and dove in its majestic swoop.

Sperm whale (Physeter macrocephalus) diving
Sperm whale (Physeter macrocephalus) diving
Sperm whale (Physeter macrocephalus)
Sperm whale (Physeter macrocephalus)
Sperm whale (Physeter macrocephalus) tail fluke
Sperm whale (Physeter macrocephalus) tail fluke

I would like to have got better photos, but one gets what one is given, and I am grateful to have seen it. The last image is of the big flukes disappearing beneath the waves.

Sperm whale (Physeter macrocephalus)
Sperm whale (Physeter macrocephalus)

You don’t have to go all the way to Indonesia to see Sperm whales, they have a global distribution and are found around the shores of the United Kingdom. Indeed, there have been a number of high-profile stranding in recent years. Six sperm whales beached in Norfolk and Lincolnshire in 2016 (5). And a total of 29 stranding on the shores of the North sea as a whole in 2016.

Whilst there are records of these whales stranding as far back as 1577 (6), the fact that some of them have been found to have empty stomachs is very worrying. Especially, as the ones that beached in Germany, in Schleswig-Holstein, had stomachs which were filled with plastic debris (including discarded fishing nets) (7). Alas, we humans are fouling up this planet and the seas are filling up with plastic. It’s truly shocking. Unfortunately, it takes something like a dead sperm whale with a stomach full of plastic (or a dead albatross) to ram home the message that we are polluting the planet with our debris.

Plastic pollution
Plastic pollution
  1. http://www.fisheries.noaa.gov/pr/species/mammals/whales/sperm-whale.html
  2. http://www.iucnredlist.org/details/41755/0
  3. https://rcannon993.wordpress.com/2017/01/17/travelling-with-a-mermaid/
  4. https://en.wikipedia.org/wiki/Whaling_in_Japan
  5. http://www.bbc.co.uk/news/uk-england-norfolk-35491621
  6. http://www.seawatchfoundation.org.uk/the-sad-spate-of-sperm-whale-
  7. https://www.theguardian.com/commentisfree/2016/mar/30/plastic-debris-killing-sperm-whales