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No, it's one of New Zealand's big dragonflies, most probably the bush dragonfly Uropetala carovei, and colloquially known as the "Devil's darning needle" (presumably because of their colour & size).

And indeed, they are large creatures, as you'll see from the photos. The adult dragonfly is the biggest dragonfly in NZ at nearly 90mm long, and with wings spanning up to 130mm. This one is a male - you can tell (if you get to watch one closely) by the appendages at the tip of its abdomen.

I think he'd flown into one of the windows at work, for when we found him, he was just sitting on the road just outside & likely to be squashed by the next car to come along. When I first went to pick the big insect up up, it flapped around a bit and landed on my friend's leg (she was somewhat uncertain about this!), but eventually we shifted it onto a hebe bush away from the paths & road.

The only other specimens I've been able to observe so closely are dead & mounted in zoological collections, so it was quite something to see and (briefly) handle the living animal, and to observe its enormous eyes and powerful thorax & wings.

They really are great, beautiful beasts :)

dragonfly 1a.jpg

dragonfly 2a.jpg

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Once upon a time, I wrote about traumatic insemination in bedbugs. (Those of my friends who are still traumatised by learning about the reproductive habits of various slug species may not wish to follow that link.) Now, two papers just published in Nature Communications describe the results of sequencing & examining the genome of the common bedbug, Cimex lectularius

Bedbugs have probably been with us since humans first lived in caves, where the bugs jumped (possibly literally) from bats to Homo. They're now a widespread human ectoparasite (found on every continent apart from Antarctica) and have developed resistance to the pesticides once used to control their populations. In introducing their paper on their analysis of the C.lectularius genome, Rosenfeld & his colleagues (2016) comment that

There is a limited molecular understanding of the biology of the bed bug before, during and after feeding on human blood, which is essential to their life cycle since bed bugs are temporary ectoparasites, whereby they access their hosts for blood feeding and then seek the refuge of the indoor environment for digestion, waste production and mating.

To increase our understanding of the bugs' life cycle, Rosenfeld's team looked not only at the genome sequence but at changes in gene expression, finding the most pronounced changes occurred after the insect had sucked its fill of human blood. They also found that these changes in expression 

included genes from the Wolbachia endosymbiont, which shows a simultaneous and coordinated host/commensal response to haematophagous activity. 

In other words, gene expression in both host and parasite changes in a synchronous way after the bug has fed. (Just as an aside, Wolbachia is a bacterium that has a significant impact on the reproductive lives of its host.) In the bugs the change could be described as huge: "20% of all stage-regulated genes" showed differential changes in expression after a blood meal.

As you'd expect, the bugs have a number of genes with anticoagulant activity - after all, having blood coagulate in their needle-like mouthparts while feeding would really gum things up - plus other genes associated with blood-feeding. The research team also identified a number of mutations that confer resistance to pesticides such as pyrethroids & cyclodienes, plus others that may underlie metabolic changes that speed up detoxification. Genes that have an impact on the thickness of the bugs' cuticle also have an impact on resistance (also noted by Benoit et al. 2016). 

In the second paper, Benoit and his colleagues (2016) also analysed the common bedbug genome to produce

a comprehensive representation of genes that are linked to traumatic insemination, a reduced chemosensory repertoire of genes related to obligate hematophagy, host–symbiont interactions, and several mechanisms of insecticide resistance.

Traumatic insemination involves male bugs stabbing their sexual partners pretty much anywhere on their bodies with a sharp, pointy, penis. It's a habit that can lead to the females picking up a range of pathogens, and unsurprisingly natural selection has driven the evolution of a range of adaptations minimising the physical harm and risk of infection. 

Because the bugs are obligate blood-feeders (haematophagous), their chemosensory system has evolved to allow them to find their particular hosts (ie us). The team observed that the genes involved in this system differed between C.lectularius & the related species that feeds on bat blood, as the 2 species have specialised on different hosts. They identified a total of 102 genes involved in chemosensory pathways, well down on the number found in related bugs (hemipterans) that feed on a range of plant species. (On the other hand, they have a much-expanded repertoire of salivary enzymes, compared to the plant-sucking bugs.)

The bedbugs' specialisation on human blood as their sole food source did have some potential pitfalls, as apparently vertebrate blood lacks some of the micronutrients that arthropods require. And that's where Wolbachia comes back into the story: 

such specialization also drives obligate associations with symbionts, including Wolbachia, that generate critical micronutrients that are deficient in vertebrate blood (Benoit et al., 2016).

Wolbachia does this by providing its host with 

a cocktail of specific B vitamins that are critical for reproduction and development

The research team also found genes encoding proteins (aquaporins) that allow the bugs to rapidly shed the excess water imbibed in a blood meal, and concluded that differential expression of aquaporin genes (and others) allow the bugs to survive periods of starvation and dehydration in between hosts.

In their conclusion, Benoit et al. comment that the wealth of information uncovered by these genomic studies may allow us to move towards an answer to a pressing question: 

What triggered the current bed bug resurgence?

To which harassed travellers would probably add, and how can we bring them back under control?

J.B.Benoit, Z.N.Adelman, K.Reinhardt, A.Dolan, M.Poelchau, E.C.Jennings, E.M.Szuter, R.W.Hagan, H,Gujar, J.N.Shukla, F,Zhu, M.Mohan, D.R.Nelson, A.J.Rosendale, C.Derst, V.Resnik, S.Wernig, P.Menegazzi, C.Wegener, N.Peschel et al. (2016) Unique features of a global human ectoparasite identified through sequencing of the bed bug genome. Nature Communications 7 Article number 10165 doi:10.1038/ncomms10165

J.A.Rosenfeld,D.Reeves, M.R.Brugler, A.Narechania, S.Simon, R.Durrett ,J.Foox, K.Shianna, M.C.Schatz, J.Gandara, E.Afshinnekoo, E.T.Lam, A.R.Hastie, S.Chan, H.Cao, M. Saghbini, A.Kentsis, P.J.Planet, V.Kholodovych, M.Tessler et al. (2016) Genome assembly and geospatial phylogenomics of the bed bug Cimex lectularius.  Nature Communications 7 Article number: 10164 doi:10.1038/ncomms10164

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By now many of you have probably seen images of green-glowing zebrafish, or pigs whose snout & trotters glow in the dark. In both cases the animals are genetically modified and are expressing a fluorescent protein originally sourced from a jellyfish. (The body form of a jellyfish is a medusa, while that of sea anemones & their freshwater relative, Hydra, is called a polyp.) There are a range of these proteins, which collectively belong to a group called the Green Fluorescent Proteins (what else?), and while a wide range of jellyfish produce them1 there are only occasional reports of glowing polyps.

However, in a paper just published in the open-access journal PLoS ONE, Andrey Prudkovsky & his colleagues describe finding tiny (~1.5 mm) fluorescent polyps living in the Red Sea. More specifically, growing in colonies on the shells of small gastropods, a relationship described as epibiotic. The snails are active at night on the sandy seabed, and the researchers noted that the little gastropods buried themselves in the sand when a torch shone on them. They also noticed that the snails, as they moved about in the moonlight, were covered with tiny pinpoints of green light.

Where fluorescence has been described in other polyps, it's mostly been in the 'stalks' of the little animals, but in all the polyps Prudkovsky's team studied, the intense green glow came from a region known as the hypostome - the region around the animal's mouth & encircled by its tentacles. Because both the intensity and the site at which the proteins are expressed is so unusual, the researchers suggest that this could be a useful taxonomic characteristic, given that it's hard to tell one colonial polyp species from another.

They also speculate on the adaptive significance of a polyp having a green glow around its mouth, suggesting that 

[f]luorescence in the hypostome of Cytaeis sp. has probable ecological significance as prey are likely to be attracted to the tentacles and mouth of the polyps

although I do feel that until there's actual observational evidence of this happening, it's a little like an evolutionary just-so story. But isn't the combination of little snails and glowing polyps rather beautiful?

Fig 3.  Hydroid polyps of Cytaeis sp. from the Saudi Arabian Red Sea, scale bar 2 mm; (A) fluorescence of living polyps on the shell of the gastropod Nassarius margaritifer; (B) polyps on the shell of a N. margaritifer specimen, scale bar 2 mm; (C) close-up of polyps, scale bar 0.5 mm.

Fig 3 From Prudkovsky et al., 2016: Hydroid polyps of Cytaeis sp. from the Saudi Arabian Red Sea, scale bar 2mm; (A) fluorescence of living polyps on the shell of the gastropod Nassarius margaritifer; (B) polyps on the shell of a N.margaritifer specimen, scale bar 2mm; (C) close-up of polyps, scale bar 0.5mm. doi:10.1371/journal.pone.0146861.g003

1 And also in comb jellies, marine arthropods, and cephalopods cephalochordates (thanks to herr doktor bimler for picking up the evidence of my brainfade).

Prudkovsky AA, Ivanenko VN, Nikitin MA, Lukyanov KA, Belousova A, Reimer JD, et al. (2016) Green Fluorescence of Cytaeis Hydroids Living in Association with Nassarius Gastropods in the Red Sea. PLoS ONE 11(2): e0146861. doi:10.1371/journal.pone.0146861

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When I was a kid I used to collect shells on the beach - got my Girl Guides 'collectors' badge & everything :) So I really enjoyed reading this post over on Sciblogs NZ. And that in turn reminded me of an article I saw recently on microsnails.

According to that article, 

"Microsnail" is the term for the creatures with shells measuring 5 millimetres or less, sometimes much less (Milius, 2016).

So these are some seriously tiny creatures. According to National Geographic1, microsnails are relatively common (albeit with any given species having a fairly restricted range), but they're just so small that people don't notice them. (NatGeo has an error in the first sentence of that story: I think they meant to say that the snails are a fraction of an inch tall.) However, they are a very diverse group: a 2014 paper on microsnail taxonomy (Jochum et al.) states that snails less than 5mm in length

represent the majority of worldwide tropical land snail diversity. 

The NatGeo story is based on the recent description of 7 new species of microsnail from China, the smallest of which, Angustopila dominikae, could fit in the eye of an ordinary sewing needle: its shell is just 0.86mm long2. Apparently A.dominikae held the mantle of 'smallest land snail in the world' for 5 days, before being knocked off its perch by an even smaller snail from Borneo. 

That there are so many of these tiny species of gastropod shouldn't really come as a surprise: there are more microhabitats available for smaller creatures. (Think, for example, of the tiny eyelash mites that frolic on our faces at night.) But those microhabitats may be limited in extent and that can be a problem (for creatures and those classifying them alike). In the case of the microsnail genus Plectostoma,

many species only occur on a single hill and nowhere else on earth.

And as described in this post on

Limestone hills are 'sitting ducks' for mining companies, and many are being quarried away for cement, taking their unique snails  with them to their grave. One species, Plectostoma sciaphilum, is already extinct: its home was turned into concrete around 2003. Similar fates await at least six more species. One of these, P. tenggekensis (named and described in the new paper) occurs only on Bukit Tenggek, which the authors [Liew et al., 2014] forecast to be completely gone by the end of 2014.

Sad to think that these jewel-like creatures may be disappearing from the world even faster than scientists can catalogue them.

Photographs of 17 living Plectostoma species from Liew et al., 2014. Image credit T.-S. Liew.

1 NatGeo has an error in the first sentence of that story: I think they meant to say that the snails are a fraction of an inch tall.

2 Now, if that's their adult size, imagine how tiny the juveniles must be! 

A.Jochum, R.Slapnik, M.Kampschulte, G.Martels, M.Heneka & B.Pall-Gergely (2014) A review of the microgastropod genus Systenostoma Bavay & Dautzenberg, 1908 and a new subterranean species from China (Gastropoda, Pulmonata, Hypselostomatidae). Zookeys 410: 23-40. doi: 10.3897/zookeys.410.7488

T-S Liew, J.J.Vermeulen, M.F.bin Marzuki & M.Schilthuizen (2014) A cybertaxonomic revision of the micro-landsnail genus Plectostoma Adam (Mollusca, Caenogastropoda, Diplommatinidae), from Peninsular Malaysia, Sumatra and Indochina. Zookeys 393: 1-107  doi: 10.3897/zookeys.393.6717

S.Milius (2016) The fine art of hunting microsnails: beauty and sorrow in five millimetres or less. Science 189(2): 4



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Following on from the private lives of snails, I bring you: slugs! (The first part of this post is largely a repost of something I wrote back in 2009.)


Leopard slugs, like other terrestrial slugs & snails, are hermaphrodites. They produce both eggs & sperm, but must exchange sperm with another slug in order to fertilise their eggs. (This reproductive strategy means that an amorous snail or slug doesn't have to find a partner of the opposite sex, it needs only to meet another snail. Or slug. Of the same species, of course.) Actual copulation is preceded by a range of somewhat slimy courtship & precopulatory displays - in garden snails this involves (among other things) piercing one's partner with crystalline darts... Sounds painful, I know, but this part of the ritual apparently enhances uptake of the piercer's sperm by its partner.

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I love words (to the extent that I've been known to peruse dictionaries for pleasure). The Story of English was one of my favourite TV programs, back (long way back) in the day. So of course when I saw positive reviews for Robert Macfarlane's book, Landmarks, of course I had to get hold of a copy. For, as the author says, 

This is a book about the power of language,... It is a field guide to literature I love, and it is a word hoard of the astonishing lexis for landscape that exists in the comparison of islands, rivers, strands, fells, lochs, cities, towns, corries, hedgerows, fields and edgelands uneasily known as the British Isles.

I could tell I was going to enjoy the book as soon as I read that first paragraph. This isn't going to be a book review, because I haven't finished it yet. But I do want to share my thoughts on something else that Macfarlane says, very early on (in explaining his reasons for writing it). 

For he dicovered that a new edition of the Oxford Junior Dictionary (my kids had to have their own copies for school) had removed a number of words from its lexicon:

A sharp-eyed reader noticed that there had been a culling of words concerning nature. Under pressure, Oxford University Press revealed a list of the entries it lno longer felt to be relevant to a modern-day childhood. The deletions included acorn, adder, ash, beech, bluebell, buttercup, catkin, conker, cowslip, cygnet, dandelion*, fern, hazel, heather, heron, ivy, kingfisher, lark, mistletoe, nectar, newt, otter, pasture and willow.

In their place, the editors had added terms bearing on modern technology, including "attachment, block-graph, blog, broadband, bullet-point, celebrity, chatroom, committee, cut-and-paste, MP3 player and voice-mail".

Now, I'm not someone who resists changes to the language. I know words change their meaning over time (which is why etymology is so much fun), and I know that words fall out of favour and into disuse, eventually to be lost. But that's different from an editorial board making a conscious decision on what words are more, or less, important for children to know and understand. 

The OUP editors were happy to explain the changes to Macfarlane: earlier editions had a reasonably large contingent of 'nature' words because a larger proportion of the population lived in semi-rural areas and would see plants, animals and the seasons on a regular basis.

"Nowadays the environment has changed." There is a realisim to her response - but also an alarming acceptance of the idea that children might no longer see the seasons, or that the rural environment might be so unproblematically disposable.

Now, words have a certain power. Of course you can convey a powerful message in relatively few short words! But a complex vocabulary allows precision in description, and (Macfarlane thinks, and I agree) also allows a sense of connection with the world. Not only is it sad to think that children may see less of the natural world these days, but it's a concern if with the loss of vocabulary comes a reduction in the ability to engage with any precision in describing and understanding the natural world.

There is, after all, a big difference between knowing that something's a tree, and knowing that it's a particular type of tree with its own particular niche. If we lose the feeling of the specific that's associated with the ability to name plants or animals with exactitude, do we also lose some amount of care for their individual survival, and for their wider environment? Macfarlane certainly thinks so, & says it far more eloquently than I can.

He quotes a colleague's observation that 

as people's 'working relationship with teh moorland [of Lewis] has changed, [so] the keen sense of conservation that went with it has atrophied, as has the language which accompanied that sense.


there are fewer people able to name [the features of the natural world], and that once they go unnamed they go to some degree unseen... As we further deplete our ability to name, describe and figure particular aspects of our places, our competence for understanding and imagining possible relationships with non-human nature is correspondingly depleted ... Or as Tim Dee neatyly puts it, 'Without a name made in our mouths, an animal or a place struggles to find purchase in our minds or our hearts.'

And so the loss of these words diminishes us all.


* Dandelion's gone? Really? Dandelions pop up even in concrete jungles. If  there was one flower I might expect city kids to see, it would be that.

R.Macfarlane (2015) Landmarks. pub. Hamilton Hamilton

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Once I started paying attention to the woo around milk I realised how much of it there is. And how ready people are to accept it.

I've written about the notoriously non-scientific Food Babe before. Someone with a high pain threshold could probably manage a daily blog post on this young woman and the way she manipulates opinion, and sometimes sells the very things she inveighs against... But I digress!

Today I noticed she's shared a link about how drinking milk encourages the development of osteoporosis. I was mildly suspicious about the source (' but before taking a look I skimmed the comments. Oh dear.

Have you ever noticed how mucus forming milk is when you drink it? It's because the pasturation process has made the protiens in the milk unhealthy for your body. So what does your body do? It surrounds the protiens with mucus and rids them from your body thru the lymphatic system. 

That 'thud' was my head meeting my desk.

Following the link (& I've used 'donotlink' as I don't want to up their page traffic) induced several more thuds. Apparently the reason pasteurised milk is Bad (and they're clearly OK with 'raw' milk) is that 

the pasteurization process only creates calcium carbonate, which has absolutely no way of entering the cells without a chelating agent. So what the body does is pull the calcium from the bones and other tissues in order to buffer the calcium carbonate in the blood. This process actually causes osteoporosis.

Funnily enough, I couldn't find any data suggesting that fresh milk contains calcium carbonate (see here, for example, for the chemical constituents you'd expect). The next sentence is chemical word salad, which I suppose someone had fun making up.

And the focus on pasteurised milk is disingenuously misleading as the paper they've sort-of-cited (no actual details given, but you'll find it here) didn't distinguish between pasteurised & raw. It's also notable that holistic-living omitted the authors' conclusion - hardly surprising as it doesn't support their narrative (my emphasis):

Given the observational study designs with the inherent possibility of residual confounding and reverse causation phenomena, a cautious interpretation of the results is recommended.

Caution is needed all right, not least because the data were gathered on the basis of food diary surveys.

Caution is also needed on the holistic-living page, because it just goes on & on - including claiming that the enzymes in raw milk are essential for us to absorb the other nutrients in the milk. And conveniently forgetting that those enzymes may well not survive the stomach. And proposing links between hormones in milk & cancer, which I've blogged about before & for which there appears to be little supporting evidence. (As I said back in 2010, Medical Hypotheses doesn't count.)

Le sigh. Plus ça change, plus c'est la même chose .

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This image popped up again on FB the other day. It was originally posted, with the comments I've pasted below, on a page run by/for someone called 'Dr Sebi'. I do not recommend asking his advice. After all, I'm doubtful that someone who could say something like this, in advising people what not to eat

Cauliflower - It is worse than broccoli. It will rob you of your minerals. It has no carbon.

has a particularly good grasp on biology, chemistry, nutrition - or science, really. And in case you were wondering, here's the advice around brocolli: 

Broccoli – Being that broccoli is hybrid, unnatural, incomplete molecular structure, it should not be consumed by humans. It’s an acid based vegetable. It has no nutritional value and is worse than okra and spinach.

This is what followed the image; sadly, it does not seem to be a poe :( There do appear to be people out there who believe this nonsense. 

Cow is a hybrid between a Yak and Buffalo. Meaning they mated a Yak and Buffalo and out comes a hybrid that we know of as a cow.

No. Not even close. Those interested in the origins of domestic cattle will find a wealth of information on the Berkeley evolution page, but basically they're derived from aurochs via a number of independent domestication events. (Interestingly, it appears that a breeding program has led to the production of animals that more closely resemble what we know of aurochs than they do modern cows, with some of those animals released into the wild in several European countries.)

If God made it, the milk would be on the alkaline side of 7 or higher. The pH of cow milk is between 5.5 and 6.0 while the buffalo's and yak's milk has a pH of 9.

Now, how on earth would they know what a designer intended? But wait - the focus on an alkaline food makes it fairly clear (as does a perusal of some of 'Dr' Sebi's claims) that this is aimed at people who buy into the nonsense that is the alkaline diet. It is also aimed at people who don't understand what pH really means - and who presumably do no fact-checking of their own. For cow's milk is slightly acidic, with a pH of around 6.7,  while human milk varies between 7 & 7.4, depending on the stage of lactation. (Perhaps 'Dr' Sebi's adherents should oppose breast-feeding too?) The pH of yak milk is around 6.4, and while I couldn't find any data on buffalo milk there's no reason to expect it to be much different. 

What do you have in milk? penicillin, puss, blood, and steroids. Milk is heated up over 212°F because you don't want bacteria in it (they take the cow and hook it up to a machine to milk the cow, but the machine doesn't know when the cow is done and it keeps pumping and puss and blood gets into it). So now you have white plastic puss and blood in your body.

I'm not sure whether their concerns around penicillin relate to human ingestion via milk, or to the development of antibiotic resistance in bacteria found in farm animals that can then be passed on to human pathogens. But anyway, in NZ and many other countries there are very strict guidelines about the use of antibiotics, and their presence in milk can lead to farmers being penalised and the rejection of an entire tank of milk. For this reason, milk from animals suffering from mastitis and which are being treated with antibiotics, must be handled separately and can't be sold for human consumption.

Milk doesn't have 'pus' in it1 but it may contain a certain level of 'somatic cells'. These may include damaged cells from the udder but are mainly white blood cells, which increase in number if the cow is suffering from an infection. (In fact, somatic cells counts and bacterial2 cell counts are two indicators of milk quality. They are not inherently a bad thing, and I can only assume that our writer gets most of his information from sites such as and, both of which push the idea of pus and blood in milk quite stridently. (I am not going to link as they don't deserve the traffic.)

Cows milk is made for the bulk of the calf sooo immediately humans are gonna get bigger from that because we're drinking something that's molecular structure is so large. This is why we don't promote cows milk or any other animals milk in this group. Homemade hemp, coconut, brazil nut, and walnut milk are all ok to use.

So, humans get bigger (fatter?) because the molecules in cows' milk are bigger than those in alternative fluids? Bwahahahaha. No, seriously, this is just fantasy. While the molecular weight of caseins found in milk varies from 19 to 24 kiloDaltons, the main protein in almond milk comes in at around 63 kDa, while in coconut milk the molecular weights can get up to 52 kDa

And finally, there's the claim on the poster itself that casein is 'toxic' and causes a range of serious ailments. Unfortunately for this claim, caseins are found in human milk too. Again, this is a claim shared by mercola and naturalnews; its origins are unclear but it may go back to the book discussed here. The discussion is interesting and provides links to the scientific literature, which show that humans can digest caseins and also that the study supposedly demonstrating toxicity used doses way way waaaaay above what one might even remotely approach in real life. Plus, you do have to wonder how the Masai have survived so long.

1 As for the white plastic and puss, I have no idea. Naughty kitty!

2 And this is why we have pasteurisation.




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This morning when I went out to feed the goldfish, I encountered a pair of snails in flagrante delicto. I resisted the urge to step on them :)

However, I was reminded of a post that I wrote several years ago, on the sexual habits of snails, and thought it was worth a repost. So here goes:

Copulation in garden snails is generally preceded by (among other things) pushing 'darts' into each other's bodies. There've been various explanations for this odd behaviour (I mean, it sounds painful!), including the suggestion that the dart acts as some sort of 'wedding present' (nuptial gift), which might make the pierced partner more inclined to mating. Or that it indicates how ready the dart-shooting snail is to mate. But data from a 2001 study (Pomiankowski& Reguera) suggests another reason for this behaviour.

Snails have quite intimate, elaborate courtship rituals that involve a lot of close physical contact before actually mating. After about 30 minutes of mutual stimulation, one snail pushes a sharp pointed dart into the other. (This is often described as 'shooting', but it isn't - it's more of a hard push.) The darts aren't essential for copulation - virgin snails don't have darts, but still mate successfully. (As do snails that miss the mark - apparently around 33% of darts either don't hit the partner at all, or fail to enter their body.) So why go to the trouble of making darts (which aren't re-used, so an amorous snail must be constantly making new ones)?

It seems that the dart carries mucus along with it, & this mucus seems to paralyse the partner's female reproductive tubing. This lets more sperm make it to the sperm storage organs, where they're stored until needed to fertilise the eggs. This is important - when garden snails (Helix aspersa) mate they produce & pass to their partner a spermatophore containing 1-10 million sperm, but only about 0.025% survive in the partner's female reproductive tract (Pomiankowski & Reguera, 2001). Most of them end up in the no-return area of the bursa copulatrix, where they're digested & absorbed. But in a study of mating pairs, virgin snails that were firmly pierced by their partner's dart contained twice the stored sperm of non-stabbed virgins. And yet 

successful shooters appeard to transfer fewer sperm than did unsuccessful shooters. This suggests that successful shooters can afford to reduce the amount of sperm transferred because the penetration of dart mucus ensures a higher rate of sperm storage.

Koene & Schulenburg (2005) suggested that this may well lead to something of an arms race between the manufacture of a 'love dart' that maximises the shooter's success, and the female spermatophore-receiving organs (because the 'female' partner's reproductive success may benefit by using sperm from as wide a range of partners as possible).

But there's a lot we don't know about the finer details of snail reproduction. For example, snails may vary in how their female tracts respond to the paralysing mucus. And what's the story in those snail species that don't shoot their partners during foreplay? Hard questions to answer...

A. Pomiankowski & P. Reguera (2001) The point of love. Trends in Ecology & Evolution 16(10) 533-34

J.M.Koene & H.Schulenburg (2005) Shooting darts: co-evolution and counter-adaptation in hermaphroditic snails. BMC Evolutionary Biology 5:25 doi:10.1186/1471-2148-5-25

Mind you, the inimitable "True Facts" also does a good line on this tale :)


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Black salve. A slightly ominous name, but to some people it seems to be the best thing since sliced bread.

A colleague has just pointed me at a discussion (on FB, where else?) around the use of 'black salve' to heal a self-diagnosed melanoma. (That bit's important - the person concerned never saw a doctor & never had a biopsy, but nonetheless is describing a 'cure'.) Sadly, a lot of commenters were weighing in on how wonderful this 'treatment' was & how it does a great job of 'drawing out' the cancer, and the original discussant made this 100% incorrect claim (which I am quoting here as the page is a public one, open to anyone to view and to comment):

Black Salve only kills the cancer cells. If you put it on a spot thet is not doesn't do anything.

This is a repeated claim: that the salve will not damage healthy tissue. Yet a bit later they say: 

I overdid it on the Black Salve... piled it on... overall it [the 'cancer'] turned out to be much larger than I had anticipated.

So the large ensuing wound (& it's a nasty one) was entirely cancer, in their view.

This is what Medsafe has to say about black salve: 

Black salve and related products are promoted as an alternative to conventional medicine for treating skin problems including skin cancer. These products work by ‘burning away’ (destroying) the skin (both healthy and potentially diseased) to form a thick black scab which eventually falls off. There is no scientific evidence that black salve and similar products are effective at treating disease/skin conditions.

In other words, the user had burned away both healthy and possibly diseased tissue, creating a large open wound. (If you really want to see what this would look like, google 'black salve' and click on images - but only if you have a strong stomach as the images are nauseating. And I do have a strong stomach, and was nauseated1.)

Now, this stuff is actively promoted as a 'natural' treatment that is ever so much better2 than the 'cutting, poisoning and burning' used by the surgery and radio- & chemotherapy of science-based medicine. The irony, it burns (no pun intended): remember that we're talking about uncontrolled use of something that delivers 3rd-degree chemical burns, which indiscriminately destroy healthy and unhealthy cells alike (here's Medsafe again):

Use of Sanguinarine [the active ingredient] leads to the indiscriminate death of normal and cancerous cells and results in extensive tissue necrosis with possible secondary necrotising vasculitis.

On being challenged on their promotion of this highly dubious therapy, the original poster answered that

I did my research and I feel you are not crediting others with doing theirs.

Some responses attempted to show that using this potion - and advising others to use it - is unlikely to cure much (especially something like the claimed melanoma) and highly likely to do harm. 

Where has anyone discredited people's research? I'm sorry you think that. What concerns me is people promoting their methods and processes to other people who may be so scared and vulnerable about going to a medical person that they embark on inappropriate treatments ... Well-meaning people would be better off advising [that they] go to a trained medical person.

  But to no avail:

There are others out there that have used this method. Their you tubes were what gave me faith that it would work. 

Youtube videos = research?! [Incredulous squeak!]

Black salve has years of use, positive results, and its [sic] only the pharma trolls that go out and make it look fake/scary/dangerous.

That one has surely avoided looking at the images, which in many cases are posted by bloodroot users. And then the echo chamber starts, with others thanking the original poster for 

having the courage to go beyond and outside of the conventional method of treatment. Fear stops many from stepping outside of what 'the doctor' often prescribes. You have now left footprints for others to follow.

I can only hope that the spot this person 'treated' was neither melanoma nor metastatic, because then they may have struck it lucky, albeit by going through weeks of pain & discomfort from an escharotic wound (be warned that there is a rather graphically-unpleasant image at that link). 

I also hope that others aren't influenced by this to avoid medical care and try this 'all-natural' remedy instead; the endpoints may not be as pleasant.


1 I was even more nauseated when I got to the commenter who was advising that swallowing capsules of bloodroot - remember, this is a highly caustic burning agent - to treat internal cancers.

2 And I'm sure that it must be ever so cheap, if not free, given the way Big Pharma is so often dissed for making money through its drugs... (/snark)

Those who would like to read more about the harm that this 'treatment' can do should have a look at this article on Respectful Insolence. It includes links to images that I'm also not going to directly share here as some of them are quite literally stomach-churning in their effect. 

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