Tag Archives: spider

The Spider and the Ant

Dear All – having been weighing and counting ants on the Whistling Thorns for some research work related to my PhD. There are a few alates around – these are the winged reproductive forms of ants… Each colony produces many hundreds, even thousands of alates that take off into the sky as part of a synchronised mating flight. Female alates become future queens, they are larger than the males. Male alates only live for the day of the mating flight – they have one chance to mate. They can never return to their colony once they depart. All of them will die within a day of departing on the mating flight…

Here is an illustration of the alates of the three common ant species on the Whistling Thorn trees in East Africa:

Alates - winged queens and males of the Whistling Thorn ants

Alates - winged queens and males of the Whistling Thorn ants (the black bar is for scale - it represents 1 cm or 1o mm)

Most of the them don’t make it and end up as food for birds, other ants and spiders.

I found this Jumping Spider eating a freshly captured young foundress queen…

Jumping Spider with Acacia-ant alate (winged queen)

Jumping Spider with Acacia-ant alate (winged queen)

The spider lives among the ants and dodges them by constantly keeping on the move, occasionally nabbing one of the hapless ants for a snack! Jumping Spiders are ambush predators that use their athletic skills and fantastic vision to capture prey. They have more than two pairs of eyes (in fact 4 pairs in total, with two pairs facing forward that are very well developed…)

How many eyes can you see on the spider?

How many eyes can you see on the spider?

Incredible!

Dear All – many thanks for the kind comments and I will respond to some of the questions soon. I just found and photographed the most incredible ‘creepy-crawlies’ in my house this evening.

 

 

As I was brushing my teeth, I noticed someone watching me quietly from the corner. The area around my sink is fairly sheltered and there are several regulars who hang out there: a cave cricket, moth flies, darkling beetles and a large wall spider. This evening I noticed someone new. It took me a while to register that there was someone there watching as the interloper did not move much.

 

I took at closer look and the little eight-legged fellow that peered back at me simply blew me away. Right there in from of my eyes was one of the most elusive and remarkable spiders in the world.

 

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Everyone will be familiar with the typical spiders that construct webs and trap prey in them. This particular spider does things a little differently. This spider is commonly known as the Net-casting spider. Unlike most spiders who are simply content to sit and wait in their webs for some hapless bug to fly into it, these amazing spiders take the web strategy a step further. They weave a flexible net-liked web which they hold with the front legs. They do this dangling from a twig or some other promising perch. They support themselves using a scaffold of taut non-sticky silk that they lay down first. You can just see the lines of this scaffold in the corners in some of the pictures.

 

Enjoy the pictures of the Net-casting spider and I hope that you will be as amazed as I was…

 

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When an insect wanders by, the Net-casting spider then throws the net over the prey! Truly, truly one of the most amazing spiders on the planet. 

 

 

Big female, tiny male…

Big female, tiny male!

On a recent walk through one of the coastal forests I came across this amazing example of ‘sexual dimorphism’. This is where there are striking differences in size, shape, colour and other features between males and females of the same species. In this case it is a striking example of size-based sexual dimorphism with a gigantic female and a puny dwarf male.

Orb-weaving spiders are common in the coastal forests – among the more striking are these magnificent Nephila, who hang their massive webs, often over a metre in diameter, along forest paths. These spiders are incredible creatures. They are not just large and colourful (this one here was about 7 inches from toe to toe!), but also highly intelligent.

I have actually seen some of them gather up their webs when they see a person or a large animal approaching. After you’ve passed, they drop the web back down into place. This means that the spider doesn’t have its web snagged every time some large bumbling mammal walks by.

While taking a closer look at the spider’s magnificent web and beautiful colours, I noticed that there was another creature clinging to the web beneath her. On closer inspection I realised that this was a male. These Nephila spiders have really tiny stunted males in many species.

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The reason behind this is thought to be female aggression. The female Nephila are famously aggressive (even as I watched her from a safe distance she rotated her fangs at me like a pair of macabre bicycle pedals!). Males have gotten smaller and smaller through evolution so that they can sneak into the webs and mate with the females without getting eaten.

Males do compete for access to females, and therefore there is a trade-off: you need to be big enough to fend off the other boys, but not too big or else the female will notice you and take you for an intruder and despatch you before you can mate with her!

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In many cases the males still get eaten after they mate with the female. In fact in some spiders the males actually somersault onto the females jaws after mating with her! Notice how in this pair of would-be lovers the male is keeping to the opposite side of the web until the female yields to his charms. Just in case he needs to make a quick escape! Talk about living life in the fast lane!

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Many thanks to everyone for the kind comments. More from the wonderful world of bugs soon!