by Karen Griffiths Also published on Musemalady.com all images by Jürgen Otto With dainty legs elegantly raised in signal to mates, the peacock spider (Genus Maratus) is revolutionising how we think about arachnids and charming arachnophobes across the globe. These tiny spiders, measure just 3mmto 5mmin length are often referred to as ‘cute’ by their admirers, which is not a word people usually associate with spiders. In fact a newly discovered species of peacock spider, Maratus personatus, otherwise known as ‘blueface’ has been dubbed the worlds cutest spider. Jürgen Otto, a mite biologist at the Australian Department of Agriculture in Sydney, has been photographing and documenting peacock spiders in Australia since 2008. Previously they have been largely unnoticed, possibly due to their tiny size. Peacock spiders have long flap-like extensions from their abdomen, which are raised together with the third pair of legs during mating. This mating dance is not unlike the display of a male peacock. A new species of spider is discovered every day. With nicknames such as ‘Skeletorus’ , ‘Sparklemuffin’ and such charismatic nature we await the discovery of more species eagerly.
In the meantime stay updated with Jurgen Otto’s flickr gallery, youtube channel (Peacockspiderman) and the facebook page for peacock spiders. By Karen Griffiths Broadly put sexual selection is an explanation for the way traits may vary or be restricted to one sex. These differences can be in shape and size (dimorphism), colour (dichromatism). Sexually dimorphic traits evolve as a result of sexual selection. Fitness, as defined by the number of offspring that survive and reproduce in the next generation, differs in individuals, and is selected for by the ability of an individual to find a mate. There may be trade-offs between different components of fitness, such as a brightly coloured male lizard attracting more mates (sexual selection), but being more vulnerable to predation because of bright colour (natural selection).
The mechanisms of sexual selection are intrasexual selection and intersexual selection. Intra sexual selection is the competition for mates among members of the same sex. For example, males may fight with the victor mating with the female. Thus weapons such as horns and the better fighters will be selected for. But fighting can be extremely costly, especially to the loser. So some species use colour, as a badge of status to indicate who is more likely to be the victor, and thus avoid a fight altogether. For example some species of frogs have chest patches which indicate the amount of testosterone circulation, and thus the likely winner of the fight. The larger the chest patch, the more testosterone circulating. Inter sexual selection is essentially the mate choice among members of the opposite sex. This can be an estimate of sexual selection, for example the choice the females are making. Females constantly selecting for certain characteristics leads to selection gradients for those particular traits. Unfortunately, the need for parental care is a constraint on male reproductive success. In species where the male is crucial to the survival of the off spring, such as having an important role in care and foraging, and the female cannot care for the young on her own, then their maximum lifetime reproductive success will be lower by Karen Griffiths The red queen hypothesis describes ideas based on co-evolution. According to the red queen hypothesis, sexual reproduction persists because it enables hots species to evolve new genetic defenses against the parasites that attempt to live on them. However, simple evolution is not enought to protect the host species, there must be a co-evolution between host and parasite. This is because as the parasite species evolves new receptors to bind to a host cells and infect it, the host must evolve to in order to survive. In short a change in one species, could lead to the extinction of the other species. Therefore there is a constant arms race between species (ie host & parasite, predator & prey), where they must evolve in order to survive, or 'run' to stay in the same place.
The phrase "Red Queen hypothesis" comes from Chapter 2 in Through the Looking Glass (Carroll 1872). Alice decides that it would be easier to see the garden a garden if she first climbs the hill, to which there appears to be a very straight path. However, as she follows the path, she finds that it leads her back to a house. When she tries to speed up, she not only returns to the house, she crashes into it. Hence, forward movement takes Alice back to her starting point (Red Queen dynamics), and rapid movement causes abrupt stops (extinction) (Lively) The other idea described by the hypothesis is that co-evolution leads to occilations in gene frequencies which leads to the persistance of sexual reproduction over asexual reproduction. This hypothesis is is illustrated well in fish (Lively et. al., 1990), where the asexually reproducing individuals were shown to harbour more parasites than the sexually reproducing species, demonstrating the co-evolution favour sexually reproducing species and seperate sexes. Additionally, while sex can be a costly investment and asexually reproducing females will out compete sexually repoducing females, and rare genes may be lost; it allows for genetic and heritable variation. The advantages include the generation of new alleles, the resuffling of genes and the purging of diadvantagous mutations. References Carrol, L. (1872) Through the looking glass and what Alice found there. Macmillan, London Lively CM, Craddock C, & Vrijenhoek RC (1990) Red Queen hypothesis supported by parasitism in sexual and clonal fish. Nature 344: 864-866 Lively C, Red Queen Hypothesis http://www.indiana.edu/~curtweb/home.html My mail box is full of bills, I need some nice mail!
Email me [email protected] if you wish to swap. I will send back a postcard of the same quality when I receive your card. ♥♡♥♡ organisedcha0s #postcard #postcards #postcardswapping #postcardswap #postcardswapswanted #postcrossing #postcardforswap #postcardexchange #postcrosser #postcross #swap #swapping #swappostcard #forswap #snailmail One of the first steps to identifying an insect is to understand the variations in morphology between types. Insects have a number of different Antenna which serve useful for identifying groups. Some classes of insects have no antenna. Basic Antenna A basic insect antenna is composed of a basal (Base) segment called the scape, which may vary in length, and then a number of smaller segments which can differ significantly depending on the type. The shape and the number of segments is very important for distinguishing insect groups. Filiform Antenna Filiform antenna are long and thread like. Mantids, booklice, psocids and earwigs have filiform antenna. Mayflies have shorter filiform antenna (about the length of their heads), Dragonflies and Damselflies have tiny pointed antenna. The length of cricket and grasshopper and stick and leaf insects antenna vary greatly. Lice only have 3 to 5 segmented antenna Moniliform Antenna Moniliform Antenna are bead like Clubbed Antenna Clubbed antenna have a swollen club like tip. Antenna in butterflies are clubbed. Elbowed Antenna Elbowed antenna are prominently bent, often at 90 degrees and have a large scape Lamellate Antenna The last few segments of lamellate antenna have fan-like expansions. Moth antenna can vary from filiform to fan like. Plumose Antenna These antenna are feather like. Serrate Antenna As the name implies, serrate antenna have tooth like, or saw like segments. Aristate Antenna These antenna are short and stout with a thin, bristle like end. Recently I decided to make some science factoids with little nuggets of knowledge I have gained over the course of my studies. Some of them are very basic, a few assume some background knowledge but for the most part you needn't know anything about science in order to enjoy them. These little graphics were all made by me so if you share, please comment a link back here, or my main instagram account @organisedcha0s as they take time to make. I regularly post them to instagram, but here I will be updating them in sets of ten.
Hope you enjoy!! Karen Griffiths I want to introduce people further to the beautiful and fascinating world of insects and why I'm so obsessed with them. I thought it might be nice to share with you a few of my favourite kinds of insects. If you want to know more about what actually constitutes a insect are learn about them in greater detail, please check out my introduction to insects post here. The teddy bear beeThe teddy Bear Bee, Amegilla bombiformmis belongs to the family Apidae, Order THymenoptera. This family has some Australia's largest bees. 1 I love these bees because they look so fuzzy and cuddly, just like a teddy bear! Velvet Ants Deceptively named for their appearance, velvet ants are in fact a family of parasitic wasps. The family Mutillidae are known in many countries as velvet ants, because the female is wingless and hairy, representing a furry ant. So yes, I like furry fuzzy things! Unless you know your insects it is quite easy to mistake the female for an ant.
LacewingsLacewings, along with Antlions and Mantis flies belong to the order Neuroptera. I find that they have stunningly beautiful wings with intricate venation, indeed membranous wings with complex venation is a common trait. of the order. They are wonderous to look at under a microscope. Well, that's all for now, please comment and share your favourite insect family or species! References1. Zborowski & Storey (2010) A field guide to insects in Australia 3rd Ed, New Holland Publishers, Australia
2. Trek Nature: http://www.treknature.com/ Check out the exciting range of stationary, cards, postcards and prints which will be coming soon to the Organised Cha0s store!
So, I've spent the better part of the last year focusing on my health and hardly posted anything. But while the site is still just starting up ,I hope you can see my vision for it coming together. Everything will really take off once I find the time to write and post more regularly, and the money to get some of my designs made.
Besides postcards, prints and other stationary, I have some jewellery and keyring designs to get cut in wood and plastic, which is more expensive. Everything I intended to put up for sale here will be locally made, rather than outsourced to sites which print and sell on their own site, taking a large commission. So a lot of work to do, and on top of returning to Uni to finish my final semester now that my health is improving. So please comment and tell me what you would like to read about next! My pintrest page has really taken off and my instagram pages are starting pick up momentum so in the meantime why don't you check them out? I'd love to hear from you. |
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