Giant Eels, Dracula Ants and other reasons never to leave the house again. (Part 2)

After last week’s blog I had some very scary nightmares. I may be miles from the coast and even further from the ocean floor where the sea monsters I wrote about lurk, but no distance is enough for me to feel safe. There are Giant Squids with eyes the size of beach balls swimming around somewhere – how on earth are you supposed to relax?!

I’ve slept more soundly since I decided never to dip my toe in the ocean again. But unfortunately, there is just as much to be scared of on land too. Especially for scaredy cats like me.

I Want to Suck Your Blood (And Other Things You Should Never Say to Your Children)

If you’ve read some of my earlier blogs you’ll know I am fascinated by ants. Those teeny tiny insects are much more interesting than we give them credit for. But even I have to admit that some of them aren’t that friendly. None more so than the Dracula Ants.

Being named after the world’s most famous blood sucking vampire can never be a good thing. But these ants, found in Madagascar, take it to new creepy levels. Worker Dracula Ants go out each day to catch prey, which they bring back for their larvae to feast on. That’s all pretty normal. But it’s the peculiar feeding habits of the queen and workers which makes these insects the stuff of nightmares.

The workers chew holes in the colonies larvae and suck out their blood (or haemolymph to be scientific). Yes, you read that right. They eat the blood of their children.

http://www.alexanderwild.com/Ants/Taxonomic-List-of-Ant-Genera/Adetomyrma/

 

Just before they develop into adults, the larvae are stuffed full of lovely, delicious haemolymph. And that’s when the worker ants get to feast.

And it just gets worse. After they’ve gorged themselves on their children’s haemolymph they regurgitate it up so they can feed it to the queen! And I thought being lactose intolerant and not being able to eat cheese was a bad enough diet. (Note: Not being able to eat cheese is one of the worst things to happen to a person. Never mind cannibalism).

https://myrmecos.wordpress.com/2008/10/22/dracula-ants-at-myrmecosnet/

This delightful act is called ‘non-destructive cannibalism’ – because it doesn’t kill their larvae. If you’re a young Dracula Ant having chunks chewed out of your side doesn’t kill you, it just leaves you a bit holey. Now that’s thoughtful parenting. Larvae that have fallen victim to this strange feeding technique do show some signs of puncture wounds and scarring across their bodies.

Although it can take an even worse turn if the colony is struggling for food. In these cases the starving workers will choose the most drained and scarred larvae and use them as an easy meal.

So just to summarise. Queen Dracula Ants feed off the blood of children. But only after worker ants have sicked it up first. I think we can all agree that their parenting skills leave a lot to be desired.

You’re Giving me a Right Headache

Don’t worry – ants don’t get away with such an appalling example of child care. They’ve got their own real-life horror film to contend with. It’s not just animals that are keeping me up at night. For ants, their living nightmare comes in the form of a parasitic fungus, called Cordyceps. You know the stomach scene in Alien? Well this is the HD 3D all singing all dancing version for the insects of this world. In fact, these fungi can wipe out whole colonies without much effort at all.

When the spores of the Cordyceps land on insects, such as ants, they attack them from the inside out – growing inside their non-vital organs to replace the ant’s own tissue. Eventually the fruiting body of the fungus erupts through the back of the ant’s neck. A thin fungal spike begins growing straight through the ant’s head. Eek.

By Bernard DUPONT via Wikimedia Commons

And some of these parasitic fungi get even more impressive. They brain wash the ants they infect too and change their behaviour. They alter the chemicals in the ant’s brain and cause them to climb upwards until they grip the tip of the plant. This has been coined the ‘death grip.’ (Sounds warm and fuzzy to me.) And there’s a very good reason for this. The higher the ant goes before the delightful fungus bursts out of its head, the higher up the fungus is. And this means it can spread its spores even further – infecting even more ants and starting the terrifying process all over again.

Erich G. Vallery, USDA Forest Service via Wikimedia Commons

Cordyceps are so devastating to ant colonies that once infected workers start showing signs of being brain washed, their nest mates will dump them far, far away from the nest. Talk about taking care of your own, never leave an ant behind etc etc… And it’s not just ants that need to protect themselves.  There are thousands of different types of Cordycep and each one is specialized to infect one species! There’s no denying that’s impressive.

By Michael Koltzenburg via Wikimedia Commons

I’m really sorry to say that apparently it’s not safe on dry land either. But I read a lot about animals and there’s one thing that crops up time and time again. ‘These animals are so successful they’ve colonised nearly all areas of the globe, except high altitudes.’ So I think that means there’s only one thing to do.

Run for the hills whilst you still can.

 

 

 

 

A Bug’s Life: The True Story (Episode 4 – Ant City Life)

The Great British picnic is one of my favourite traditions – nothing says British summer like sitting on an itchy checked blanket in National Trust gardens with a wicker picnic hamper full of nicely cut sandwiches and still lemonade (sometimes I have to remind myself I’m not starring in an Enid Blyton novel.)  Unfortunately, nothing says Great British picnic more than running away from a wasp attack and watching a line of ants eye up your pork pie crumbs. Somebody forgot to tell the insects that they weren’t actually invited (how rude and very un-British to turn up unannounced without even chipping in a side dish.)

When you think about it, maybe it’s our own fault? Who can blame the visiting insects for wanting to try the exotic buffet you’ve provided right on their front doorstep. It’s not long before you will inevitably give up trying to fend off the insect attack and sit back and watch.

And when you actually start to watch the picnic ant army carefully, you see just how impressive they really are. There’s a line of teeny, tiny ants carrying pieces of crisp more than twice their size quite comfortably away into the distance. But what happens when you drop a whole crisp? Do these poor little ants admit defeat and crawl back to the nests empty handed? Of course not! Ants are pro weight-lifting champions. A whole ready salted crisp – challenge accepted – but not without the help of a few friends. Luckily for ants, teamwork is part of everyday life and it doesn’t take them long to attract other ants to help carry or break down a large food item.

By Ellmist, from Wikimedia Commons

The behaviour of ants to carry items much larger than themselves is very well known. One of the best studied examples is that of the leaf-cutters. I’m sure we’ve all seen trails of moving pieces of leaves being guided by a line of ants underneath. Leaf-cutter worker ants do spend an awful lot of time gardening – a large colony can consume as much vegetation as a cow! The funny thing is leaf-cutter ants don’t actually eat leaves. The workers take the leaves back to the nest, clean them and chew them so they’re soft and moist before using them as ant-compost on which to grow a fungus garden. The fungi that grow in this carefully managed garden produce balls at the end of each of their fungal threads, which are rich in tasty protein. It’s this protein that the ants are keen to get their mandibles on and the workers use it to feed their developing larvae.

Harvesting and moving the leaves is a truly great example of teamwork in ants. The workers cut the leaves by anchoring their legs on to them and using their mandibles like blades to slice them. These are then transported back to the nest, but the workers aren’t alone. The trails are patrolled by large solider ants with fierce looking mandibles to keep predators away and tiny ants, call minima, ride on the tops of the leaves to ward off parasitic flies. It really is all hands on deck.

Bandwagonman via Wikimedia Commons  

Ants, like other insects in the order Hymenoptera (also home to wasps and bees), display one of the ultimate examples of teamwork. They are called eusocial species and demonstrate some of the highest levels of organisation seen in social animals. Each ant working in their huge colonies has a role or belongs to a certain caste. They divide their labour into those that reproduce, the ‘queens’ and the ‘drones’ and those that don’t, the ‘workers’ and ‘soldiers’. The non-reproductive members of the colony act as housekeepers and nanny’s to the reproductive members. They ensure everyone is fed, that the young are well cared for and they protect the colony from harm.

You may think the Queen is in charge but in these societies everyone has an extremely important role to complete. The Queen lays her eggs and leaves them in the very capable hands of the worker ants. You are certainly not born with a silver spoon in your mouth in these colonies as all ants start off as equals when they’re eggs. So how do you rise to the sunny heights of the colony to become a Queen over a worker? Interestingly research has suggested it’s the workers that decide what you will become as they control what goes into your stomach. In the ant world a change of diet – such as a change from insects to seeds – can determine just how big you’ll be. The bigger the ant the more likely you are to become a solider or maybe even a queen so there is no such thing as dieting for these creatures! Ants have got this so finely tuned that the workers will respond to their environment and control the castes in order for the colony to thrive. For example, when the colony is threatened, they’ll ensure more soldiers are produced! Pretty clever, eh?

There are a couple of particular fantastic examples that show just how much ants depend on each other that I wanted to share with you..

Goodness, gracious, great balls of fire ants
When obstacles get in the way, ants don’t back down. There’s example of colonies making living bridges of ants over pools of water so the rest of the colony can get safely across. Fire ants have also come up with a pretty nifty way of surviving through floods. They build tiny ant rafts, literally tiny rafts made out of ants! They grab onto their nestmates and interlock like blocks of Lego to form a single ball of fire ants. Their skin repels water and they trap a layer of air around their bodies to form an air pocket. They’ll happily float along and wait for the flood to pass.

Raft of Fire Ants By Turnbull FL, Wiki Commons

Never leave an ant behind
I hate being underground. The thought of being trapped makes me panic – the tunnel scenes in The Great Escape may be the scariest moment of any film for me. Unfortunately, many ants choose to build their colonies underground and sometimes the worst happens- a tunnel collapses leaving an ant buried (these poor ants are living out my worst nightmare.) Luckily for these ants, help is at hand. Ants rub certain parts of their body together to produce a sound, or an alarm call to their nestmates. This is called stridulation. For ants that find themselves buried underground, they stridulate to ‘call’ ants to help. Their nestmates willingly respond, finding the place the ant is buried and they will dig intensively until their friend is free.

Bridge of ants By Geoff Gallice via Wikimedia Commons

It’s been some time since I wrote about my favourites and I started to worry they’d feel neglected if I left it any longer. I’m glad they’re back. I hope I’m starting to show you there’s a lot more to these insects than the reason your parents used to give when you couldn’t sit still as a child.

A Bug’s Life: The True Story (Episode 3 – The Hunters)

In my previous ant posts I have focused on how they form relationships with other animals or plants in order to survive.  These relationships are remarkable and usually very successful, providing the ants with shelter and access to their own food supply – but, what happens to the ants who struggle to make friends so easily?  For those colonies that prefer to keep themselves to themselves, finding food isn’t just as simple as tucking into your own dine-in experience provided by your faithful aphid or plant partners.  Instead, these ants must go out and search for their food.  The outside world can be a dangerous place; with nasty predators and harsh weather, these little creatures must take every step with care.  Lucky for us (again), these clever little ants have come up with some interesting ways of ensuring their hunting parties bring back a feast. 

Follow the leader
I couldn’t write about ant foraging without mentioning this clever little trick.  If you’ve ever seen videos of ant trails you might have wondered how they know which way to go.  Ants leave trails of scents called pheromones in order to guide nest mates in a certain direction.  These trails have allowed ants to become experts at gathering food.  A scout ant is sent out first and given the difficult task of finding food to begin with – tricky when your supermarket is an area of land of limitless size!  This scout ant can search randomly for quite some time but, still, when it finds food it knows exactly the route to take to get straight back to the colony!  On its return journey, the scout ant lays a trail of pheromones, almost like Hansel and Gretel’s breadcrumbs.  The rest of the ant-hunting party can now follow the signposts of smells straight to the food. 

Ants are definitely fans of signposting routes – some species, such as Pharaoh ants, have even been seen to use pheromones to put up “No Entry” signs in front of routes that don’t lead to a tasty meal!

However, following the leader can result in problems for the ants.  Occasionally, the ant in front will lose the scent trail.  This ant will walk in circles to search for the trail. As it does this, it leaves its own scent trail behind it.  If it doesn’t find the trail laid down by the scout ant again quickly, the rest of the hunting party will pick up the new scent and follow the ant as it goes round and round and round…  And this really is a vicious circle, literally and metaphorically – as more ants follow the new circular path, the scent trail gets stronger and stronger and more ants will join the wild goose chase.  This can lead to ant ‘death circles’ – the ants will continue to walk round and round until they die!  For these clever little creatures, this really isn’t so bright. Video link: http://www.youtube.com/watch?v=mA37cb10WMU

Beating the heat
Some ants find themselves in conditions that aren’t so great – either they’re too hot or they’re too cold!  Whatever the problem, they still have to eat and this means finding ways to cope.  The Army ants are some of the greatest ant hunters (the general name Army ants actually refers to about 200 different species).  The soldiers and workers march in huge numbers and can leave an impressive path of destruction behind them.  They work together to take down prey much larger than themselves – they have even been known to swarm dogs, killing them due to the shock of the number of bites (they don’t eat them, it’s just for defence, but it’s impressive nonetheless.)  Army ants, native to Africa and Central and South America, can find themselves in uncomfortably hot places, making foraging a dangerous game.  They protect their foragers by making roofs from bits of leaf debris to shield them from the heat!

Other ant species also have to deal with extremely hot climates.  Honey ants live in deserts and whilst the heat can be a problem, food isn’t as plentiful as they’d like and finding it can be tricky.  To cope in these extreme conditions, Honey ants have devised their own, curious food store.  They force feed a particular group of ants in the colony.  Their abdomens swell until they resemble shiny balls of honey with little ant heads stuck on the side!  When other ants in the colony are hungry they rub these honeypots with their antenna to release some of the food stored inside these ants.  The force-fed ants become living larders!

Sneaky little tricks
For some ants, finding food brings out their less-friendly side.  They use less moral ways of ensuring their stomachs are full.  Some species of Harvester ants use sneaky tricks to make sure they out-compete their rivals.  Species Pogonomyrmex and Aphaenogaster are in a sort of turf war – both species are searching for the same food and both want to find it before the other does.  Pogonomyrmex is quite an aggressive species, but it’s smarts not strength that wins this war.  Aphaenogaster early-birds sneak up on Pogonomyrmex colonies before they have stirred in the morning and block the entrance of their nest with grains of gravel.  Pogonomyrmex now have to dig themselves out of their nests before they can search for food, giving Aphaenogaster time to fill their stomachs before their rivals. 

PogonomyrmexAphaenogaster

There is something quite ‘horror story’ about the Amazonian ants Allomerus decemarticulatus.  They build nasty traps on the plants they live on to capture their prey.  They use bits of the plant to make structures like platforms filled with little holes and hide underneath them.  When their prey comes along, they grab its legs and antennae, and stretch it like a medieval torture rack!  They swarm their stretched-out prey, biting it and stinging it until it’s dead or paralysed, before chopping it into tiny pieces ready to feed their nest mates. 

And that concludes episode 3.  Ants just get more interesting don’t they?  I hope by now you are starting to agree with me.  If not, maybe the next episode will help…

 

A Bug’s Life: The True Story (Episode 2 – Making Friends)

In a previous post I mentioned my time on a field course in Portugal.  On our first day we were told to look around and see if we could find any interesting signs of biology in action.  Walking through an orchard of citrus trees, we noticed a fluffy white substance covered many of the leaves.  And we weren’t the only ones who had noticed– each patch of white was crawling with ants.  We had stumbled upon an example of one of nature’s finest relationships.  The cause of the white, fluffy patches was an infestation of woolly white flies.  These tiny little flies have formed relationships with ants for hundreds of years.  And they aren’t the only ones.  Many insects similar to aphids (given the group name of hemiptera) survive because of their close interaction with ants. 

So why do ants and aphids make such good friends?
It’s not just out of the kindness of their hearts.  This is another relationship where ants are just out for what they can get (such material girls).  In this case it’s food- lots of lovely sugary honeydew to be exact.  Aphids are sap drinkers.  They live on plants and feed by inserting their long, thin mouth-parts into the plant, sucking up the sap like they’re using a straw.  Insects, like plants, require lots of lovely nitrogen.  Whilst the plant sap contains some nitrogen, it is only a very small amount which means the aphids have to drink loads of it in order to get enough of this precious nutrient.  Sap is also really rich in sugars, most of which the aphids don’t need.  This is where the ants come in.  The excess sugar oozes out of the aphids bottoms, forming a sugary droplet.  This sugary secretion, called honeydew, makes an extremely tasty meal for the ants.

Ants have been using aphids as all-you-can-eat sugar buffets for hundreds of years.  This has allowed their relationship to become quite sophisticated which is where it gets really interesting…

Ant as farmers
As ants rely on the sugar produced by their aphid partners, it would be good if there was a way to make these aphids produce even more of it.  Ants have found a way and have taken on the role of farmers to make it happen.  They tend to their aphids like cattle, shepherding them to the best places on the plant for collecting sap.  The relationship gets even more fascinating with some ants branding their aphid like cattle, by marking new-borns with a substance unique to their colony.

Did you know you can also milk an aphid? Whilst you won’t get anything to put on your cornflakes, it is possible to encourage aphids to produce honeydew.  Ants have been seen to stroke aphids with their antenna to stimulate the production. (Video: Ants milking aphids)

Perhaps my favourite thing of all, some ants have been known to build their aphid flocks shelters in bad weather.  Using little bits of soil and leaves they keep their aphids safe from the harsher elements. One species, the honey ants, have been seen to store the eggs of their aphid partners when temperatures are poor, protecting them until conditions improve and they can be replaced back on the surface.

Ants as contraception
When aphid populations get to a certain size, some individuals decide it’s time to fly the nest and make their own way in the world.  Some of the aphids moult and emerge as sexually mature individuals with wings, ready to fly away and find that special someone to mate with.  This is obviously not good for the ants.  You can’t have half of your food supply suddenly growing wings and leaving.  They have therefore developed a neat little trick to keep their food firmly on the ground.  When they lick the honeydew off the aphids, they also transfer some substance that somehow prevents the aphids from becoming sexually mature.  This means the aphids won’t develop wings and fly away and the population will grow and grow without any limits.  This is excellent news for the ants (but not so good for the plants the aphids are sucking dry!).

Ants as protectors
So far I’ve only mentioned how the ants benefit from their relationship with aphids.  But the aphids do get their reward as well.  A build-up of honeydew can attract fungus which can damage the plant and this obviously wouldn’t be good for the aphids.  So it’s a win-win situation- the ants enjoy a tasty meal, and remove the risk of harmful honeydew build-ups, which means there’s more healthy plant for the aphid to enjoy.

But ants provide more than just a removal service – the aphids also get their own team of bodyguards.  The ants will attack any predator that comes near to their precious herd.  This is vital, particularly as it’s tricky for the aphids to quickly remove there long mouth-parts from the plant when a predator attacks.  Some ant species become very aggressive in order to protect their aphids and have been known to attack species they would not usually attack.  In the case of the honey ant, the ant has been known to even destroy the eggs of predators. I saw this first-hand in Portugal.  Being the cruel scientists that we are (it was all in the name of knowledge I swear), we placed earwigs into dishes containing ants and woolly whitefly covered leaves.  The ants turned into fighting machines and commenced a vicious attack against the earwig- I witnessed (and even encouraged) a lot of attempts to relieve the earwig of its limbs and antenna.  That’s what I’d call a committed bodyguard. (Video link: Ants protect their aphids from a ladybird)

So next time you and your friend fall out why not go and find an ant.  They keep you well-fed, safe from harm and even wipe your bottom for you (as long as it’s covered in honeydew).  You’ll have a friend for life (or at least until a group of aphids comes a long).

The wonderful (and slightly weird) world of animal defences

There are so many things about the world that fascinate me that it really was hard to pick exactly where to begin! So I decided to take inspiration from the Wolverine frog I mentioned in my previous post. 

Unfortunately, the animal kingdom isn’t always as joyful as Walt Disney would have you believe, ignoring of course Bambi’s mum and poor Mufasa- may they rest in peace.  (Although I, for one, think it would be great if next week’s Africa showed a hippo and a zebra performing a musical number by a watering hole).  As David Attenborough so often shows us, the animal kingdom can be a brutal place.  Therefore, arming yourself with an impressive display of defences is vital.

There are many ordinary ways to defend yourself, such as large claws, antlers or pincers.  Whilst these may be effective, they’re just a little bit boring aren’t they (No offence to the tigers, deer and crabs of the world).  Luckily for us, some animals have gone that extra step to develop amazing, sometimes hilarious and sometimes absolutely ridiculous ways to protect themselves from harm.  I have picked some of my favourite ones for your enjoyment…

Malaysian ants
Ask any member of my family and they will tell you, I have a sad secret. But I’m ready to admit it to the world. I love ants. I spent a week in Portugal sucking them from trees for my 3^rd year project (I did accidentally eat a few. I wouldn’t recommend them to a friend- unless you find the taste of acid enjoyable).  Before this my only real experience of ants was sitting with my brother and sister on holiday dropping bits of crisp near a line of ants to see how big a piece they could carry away (our own ant weight-lifting competition if you will).  By studying them I soon realised just how cool these little insects were.  So it’s only right that I mention at least one of them here.

Malaysian ants have chosen an interesting (but strangely not unique) way to defend themselves.  They have two, large glands that run the whole length of their body filled with a sticky, corrosive substance.  When they are seriously threatened, they contract their abdomen causing themselves to internally combust, spraying the contents of their glands (not to mention little tiny pieces of ant) all over their enemies.  Although blowing myself up wouldn’t be my first choice of defence, for a social species like ants, sacrificing yourself to defend the rest of your colony is actually worthwhile.

Horned lizard
Despite its name the Horned Lizard doesn’t have an impressive set of head gear it uses to fend off predators.  Instead, some of these lizards force the blood vessels in their eyes to explode creating a stream of squirting blood from their eyes (that can travel as far as 5 feet!)  By limiting the blood that leaves their head, they increase their blood pressure, causing the blood vessels around their eyes to burst.  Covering your predators in your own blood is certainly one way to scare them off.

Hairy frog
I can’t have a post on weird defences without mentioning the X-men frog again.  Actually called a Hairy Frog (definitely not as good) these frogs are capable of breaking their own bones in their toes and hands (if frogs can have toes and hands) that break through their skin forming defensive claws.  They are then apparently able to retract them and regenerate their damaged skin (they just get even more like Wolverine).

Virginia opossum
Last but not least, the Virginia opossum. This is, to me, the most hilarious of animal defences.  You’ve got no impressive antlers or pincers and you can’t make your own eyes explode, so what do you do?  When all else fails, take a leaf out of the opossum’s book and just pretend to already be dead.  When this animal senses a predator, it lies rigid on the floor, tongue out, eyes open with maybe even a little foaming at the mouth for good measure. It also secretes a foul smelling liquid from its bottom in order to further put-off its predators. It might sound silly but it’s effective- what self-respecting predator wants to eat a gone off Virginian opossum?

I seem to have blabbed on again.  Maybe I’ll stop apologising and just admit it’s going to happen every time.  I am definitely one of life’s wafflers.  I hope you enjoyed it. But please if you find yourself in a confrontation, don’t try any of these at home.  Except the playing dead one (but please let me know if you’re going to try it out in an argument, I’d love to see how it works out).