Wellington Tree Weta
An original post, title – the Wellington Tree Weta (Hemideina crassidens)!!!!!
The male Wellington tree weta looks even more fearsome than the female weta. Their heads are about twice the size and they have oversize jaws that they use for fighting. The biggest, strongest male weta set themselves up in the best real estate and accumulate a harem of up to five females; lesser males are fought and repelled. The fights are not to the death but bits and pieces, like legs or antennae, can be lost during the battle.
Some good pictures of weta, including this male can be found here and here.
Any fighting takes place at night. By day, the weta pack themselves tightly into “galleries or holes in trees and fallen wood. Starting with a hole made by an insect, or where rot has set in, the weta move in and can chew away wood and bark to enlarge their holes. It is possible to make weta motel like the one pictured. The New Zealand Department of Conservation has published instructions for a three star unit and a very sophisticated five star weta motel.
At this time of year (spring), the eggs that were laid during the previous autumn and winter start to hatch. The female weta uses her ovipositor (egg-placer), the long curved spike on the rear of her abdomen, to force the eggs down into the soil. The ovipositor
of this female can just be seen.
The weta hatchlings have to shed their external skeleton as they grow. Over one – two years, the mini weta sheds or moults at least 10 times before reaching their final size (4-6 cm long). Most adult weta live for around 10 months. The one very notable exception is the alpine weta, which can survive freezing winter temperatures and live for several years.
Wellington tree weta are found in suburban gardens in the lower half of the North Island.
They are the ones our cats catch, that we find on the firewood and that surprise me when I am perched precariously in a tree, trying to remove dead branches. Here’s hoping for a big weta hatching this spring to keep gardening interesting.
Oops, sorry
For the recent lack of activity.
Too many big assignments due at the end of the year, followed by school holidays, end of semester parties and flat moving.
New fascinating and scintillating stuff coming soon,
Michelle, Julia and Emily.
Tusked Weta
The ferocious looking tusked weta male has two long, curving tusks protruding from its jaws. The tusks are used for fighting other males – to push and flip an opponent. Females do not have tusks and look similar to tree weta.
Tusked weta are carnivorous, preferring to dine on worms and insects. They themselves are preyed upon by tuatara, and by introduced rodents.
Three species have been identified: the Northland tusked weta, the Middle Island (Mercury Island weta) and the Raukumara tusked weta.
The Middle Island tusked weta, which lives in shallow soil burrows was only discovered in 1970. The New Zealand Department of Conservation has established a breeding program to rescue this huge insect from the brink of extinction. A great video showing the size and talking about the weta can be found here. (Video is really worth watching!)
The Raukumara weta was discovered even more recently, in 1995/6, in the Raukumara Ranges of the East Coast of the North Island. This recent discovery shows how little we know about the New Zealand weta. The lack of basic information on the existence, distribution, abundance and ecology of weta makes it very difficult to manage their conservation. Even identifying which species an animal belongs to is difficult as there is huge genetic variation in populations.
The conservation of weta is an evolving process that is constantly being modified as new information and new insects come to light.
Wars in the Womb
Imagine having to fight for your life amongst those around you, while you are still labeled an embryo. For most of us, we are perfectly safe in the womb, save the odd struggle with a twin/triplet for room.
The Grey Nurse Shark is an exceptional animal, not only because the species has survived being wrongly accused of shark attacks over the decades leading to its hunt, but because the embryos inside the uterus fight and eat each other.
The female shark has two uteri and within each, one embryo will be victorious having eaten its siblings. The result is the birth of two super-young.
This is labeled intrauterine cannibalism. This reproductive strategy has evolved to produce sharks that are only the strongest and already suited to their harsh environment.
This is a form of oophagy, a term which describes when embryos eat their own egg yolk and then other eggs from the uterus while still holed up in there.
This peculiarity is highly common in most sharks, especially those from the order Lamniformes.
Even weirder is ovophagy, where one sibling eats the rest right before birth. Little research exists however and ovophagy is extremely rare.
Lights, camera, action
I recently came across a reference to the phenomenon of sonoluminescence, using sound to make light.
Sonoluminescence can occur when an intense sound wave collapses a bubble quickly. The light produced is very weak and last for a very short time.
From left to right: apparition of bubble, slow expansion, quick and suddenmcontraction, emission of light http://en.wikipedia.org/wiki/Sonoluminescence
The bubble might be pre-existing or is might be formed by a process called cavitation. When a liquid is subjected to rapid changes of pressure, cavities form in the lower pressure
regions of the liquid. If the bubble or cavity collapses rapidly, sonoluminescence and a shockwave are produced. Some sea critters stun their prey using this principle.
One is the pistol (or snapping or alpheid) shrimp; another is the mantis shrimp (stomatopoda), which is neither a mantis or a shrimp. (It’s a crustacean.)
Both animals strike so rapidly with their claws they generate cavitation bubbles. The
collapsing bubbles produce measureable forces on their prey. The unlucky victim is hit by a double whammy; the impact of striking appendage and then the forces from the collapsing cavitation bubbles. Just the shockwaves can be enough to kill or stun the prey.
Even though pistol shrimps are only about 3-5 cm long, the snapping sound is so loud that it is one of the loudest animals in the sea. Colonies of pistol shrimp can interfere with sonar and underwater communication.
Mantis shrimp are much bigger and can grow to 30 cm or more. They are usually separated into two groups, based on the types of claws they have.
- Spearers are armed with spiny appendages topped with barbed tips,
used to stab and snag prey soft prey like fish. -
Smashers have a much more club-like
appendage, which is used to bludgeon and smash through the shells of crabs and
molluscs.
The sonoluminescence is thought to be a side effect of the rapid snapping motion and not have any biological significance. Which is a pity as it would be an interesting way to signal “you’re hot” to the passing talent.
Drawing of a mantis shrimp, 1896.
Anglerfish males – she only loves you for your balls…
Browsing the internet the other night, as you do, I came across this comic (beware, it contains bad language):
http://theoatmeal.com/comics/angler
When I first read this I was amazed, I have heard of angler fish of course and had seen some model ones at a museum exhibit on the deep sea, one even tried to eat Dory and Nemo’s dad - but I had never given much thought to how they procreate. So I looked them up to see if the cartoon was true and low and behold it is.
Male anglerfish are born with a great sense of smell but really not much else going for them. They are small and they have trouble finding food. Their sole mission in life is to find a female (which they locate using that highly developed sense of smell).
When they find a female, they need to get her attention, so the male fish bites her. This unfortunately for the male causes her to release an enzyme that dissolves his mouth and fuses him with her body. Once that is done, the male slowly atrophies. His digestive system goes first, then his brain, heart and eyes. Eventually he is reduced to nothing but a pair of gonads which the female can use when she is ready to spawn.
Sounds pretty horrendous but anglerfish aren’t the only femme fatales in the animal world.
Many types of spiders kill or eat their male partner after mating. And praying mantis females rip the heads off their mates once they are finished with them. Scorpions will attack anything that moves, including unfortunately their mate. Even female sea slugs have been known to eat their mates.
It’s not all bad news for the boys though, the New Zealand paddle crab turns the tables; males sometimes eat females while mating.
Wormy Squirmy
Last Friday I had the pleasure of slipping, sliding and slithering up and down a valley full of regenerating bush in South Dunedin. We were checking out the
habitat of peripatus worms.
Peripatus or velvet worms are a very small group of animals, mainly found in old Gondwanan lands. Their history goes back a very long way – they have hardly changed in appearance for 550 million years.
And they look kind of funny for a worm. They have legs (15 or 16 pairs) and modified limbs on either side of their heads. These special limbs secrete as sticky substance that the worms use to trap their prey, arthropods that live in the soil and leaf litter (spiders, beetle larvae, termites etc.). After mmobilizing their prey, Peripatus bites it, injecting it with digestive saliva then sucks out the liquified body tissues. See the Guide to New Zealand Soil
Invertebrates (great pictures!)
Five New Zealand species have been formally described, using the numbers of legs, and features of the feet to differentiate the worms. Another waysthey can be categorized is by how they reproduce. Some lay eggs and some lay eggs that hatch inside the worm, followed by apparent birth of the young. However, many other known peripatus o not fit the current descriptions.
Landcare Research also have some nice pictures of peripatus.
Peripatus are are relatively rare and several species are protected. They can found all round New Zealand, especially in moist but not wet micro habitats such within and under fallen wood and debris, including in suburban gardens. The suspected presence of peripatus may be just the excuse you have been looking for to explain the state of your garden.
This is a picture of a sub-adult worm on the palm of a colleague’s hand.
dr evil wears a fluffy coat…
Apparently there is a pretty good chance my seemingly harmless fluffer nutter is actually plotting my demise. I find I am not particularly surprised by this fact considering he woke me up in the middle of the night last night pulling my karate trousers out of my bag and attacking them. Clearly it was a sign – next time, he is saying, it won’t be your trousers feeling my wrath. Not the first time I’ve been on the recieving end of his not so subtle hinting.
Cats are fickle and its common knowledge that they lack the devotion and unconditional affection of a dog. The old saying dogs have masters, cats have staff springs to mind. I’m pretty sure the only reason my cat has let me live this long is that he has me trained to supply him with food at regular intervals.
But what makes dogs and cats different? I think it starts with how long we’ve been viewing these animals as domesticated. Dogs and people have been together for literally tens of thousands of years. Early man created a mutually beneficial hunting relationship with wolves and our domestication of our canine friends began. Next on the domestication list perhaps unsurprisingly were farm animals who have been with us for several thousand years.
Finally comes the cat. No one can really say when cats became domesticated (or really if they are domesticated at all). Clearly they’re less dependent on us than animals who’ve been domesticated for thousands of years.
The other thing that makes cats different is that they are by nature not pack animals. Unlike dogs, they are independent and don’t naturally live in packs. This is something that has been exploited over our domestication of the cat. We use them for pest control and in return we give them a bit of shelter and some better tasting (possibly) food. They probably know though that unlike a dog they could feed and shelter themselves if they felt like it.
So maybe in a few thousand years if people are still around, my cat’s relations (although not his direct descendants – snip!) will be sharing more of a mutually beneficial relationship with our human descendants. Until then though, check out this link to see if your cat is trying to kill YOU. http://www.catswhothrowupgrass.com/kill.php
A fungus grows out of an ant!
Ok so I know this is a gross topic, but I remember being told about it in one of my zoology lectures along with a short video. After much hunting, I found the video on YouTube (good old).
These Bullet ants are found in the rainforests and are feared by locals because of their bullet like powerful sting. The sting is said to be so nasty, that the ants are also nicknamed 24hour ants as the pain after being stung lasts for 24 hours.
A tribe in Brazil use the sting as a passage of right to become a warrior. Boys will have a “glove “put on their hands with hundreds of the ants woven into it, and this is left on for ten minutes. This whole ritual is repeated over several months.
The ants show very interesting behaviour though when one of their comrades are infected by the strange fungus. As the entire colony is at risk of becoming infected, a sick ant is carried far away from the colony and dumped somewhere so that when the fungus eventually kills it and sprouts, pores are less likely to infect another victim.
Seems pretty ruthless, but comparing to human behaviour, there would be hundreds of instances when our kind have done this, quarantining a leper for example, or abandoning loved ones during the black plague.
I guess it can be reasoned, in the case of the ants, that this behaviour is for the greater good.
To see this grossness but entirely understandable behavior in action, this YouTube clip shows it all: Bazarre Ant Fungus
Huia – Gone Forever
Pair of huia, Te Manawa, Palmerston North
Behavioral Ecology, a blog that keeps you up to date about the latest happenings in the
natural world, brings you the huia, last confirmed sighting, 1907.
The Huia (Heteralocha acutirostris) belonged to an endemic species of wattlebird. The New Zealand wattlebirds, which also include the kokako and saddleback (tieke) are a very ancient family of birds, with no relations anywhere else in the world. It is likely the Callaeidae ancestors flew to New Zealand 60million years ago, and evolved in a uniquely mammal free environment.
Perhaps the most remarkable feature of the huia was the differences in the shape of the
female and male birds’ bill. No other bird in the world shows such pronounced sexual dimorphism.
The female’s beak was long, thin and arched downward, while the male’s was short
and stout, like a crow’s. Otherwise, the sexes looked similar, with orange wattles and mostly black plumage with a green sheen. Their tail feathers differed from other endemic
birds, having a broad white band across the tips.
One explanation for the extreme difference in beak shape may be the huia shared the task of food gathering, with the chipping away rotten wood with his beak and female using her longer, more flexible beak to probe deeper and extract delectable huhu grubs. However, many are not happy with this explanation as this huge difference in form and function
has not been seen anywhere else.
Unfortunately, it’s impossible to resolve the argument as the huia were driven, hunted, doomed to extinction before anyone studied it.
The Maori regarded huia as sacred and wearing its feathers or skin was the privilege of those with high status. With the arrival of Europeans that small protection was lost and the bird was hunted to provide specimens for museums around the world.
Today, it’s easy to find a pair of stuffed huia in even the smallest local museum. You just won’t see them in the wild. Apart from hunting, the birds were vulnerable to habitat destruction and introduced pests. Unconfirmed sightings were reported up until
the early 1960s but no one is looking for the huia today. DNA in the vast collection of skins held by various institutions is too degraded to sequence. Cloning does not seem feasible. RIP.