Photohunter: Beautiful

I thought I'd put up a classic beauty. This guy, like many other males in the animal kingdom, has resorted to flashy, bright, and beautiful colors to attract the females. So the question is, why? Females put a lot of effort into reproduction; eggs are more energetically costly to make than sperm, not to mention the costs of rearing the chick after it is laid. Females typically (at least on land) mate fewer times than males, and with fewer individuals. Because of that, females are super choosy about who they do mate with, often wanting to make sure that they are getting the 'best genes' for their offspring.

Their choosiness often results in visual signals of a male's health and well being. In this case, by growing a long tail, they show they can gather enough food to grow such a tail and are still strong or fast enough to escape predators. The size of the eyespots on the tail has been linked with size of the bird as a hatchling. So picking guys with bigger eyespots may give the female bigger chicks. Bright plumage means that the bird does not have any parasites, this may mean that the male has some nice anti-parasite genes to pass on, or at the very least, that the female won't get any parasites while mating with him.

In short, this beautiful eye-candy is meant to show the females that they are quality picks.

Life Photo Meme: Wild Welwitschia

Kingdom: Plantae

'Phylum: Gymnospermae' (not technically a phylum, but a useful taxonomic grouping)

Class: Gnetopsida

Order: Welwitschiales

Family: Welwitschiaceae

This is an absolutely wild plant, that I would not mind seeing in the wild. This is Welwitschia mirabilis, a plant native to the 'fog belt' of the Namib desert in Africa. It is a gymnosperm, a group of plants which bear cones instead of flowers for reproduction (like cycads and pine trees), and is the only gymnosperm to have adapted to desert life. However, the male cones (male and female cones are located on different plants) have structures which resemble those found in a flower.

They are also super unusual in the way they grow. Most plants have an apical meristem which allows them to grow upwards. In Welwitschia, the apical meristem dies shortly after germination, leaving them only able to grow outward, and upwards a bit at the edges of the trunk. Think of a tree trunk that's been lopped off close to the ground, and hollowed out in the center like a bowl, and you have the basic shape of a Welwitschia trunk.

Finally, their leaves are the most unique in the plant kingdom. They are the only plant to posses permanent leaves. Most plants grow leaves from outgrowths of the apical meristem, these dividing cells bud off to form leaves at the tips of branches, or at certain nodes along the branch. Welwitschia possesses only two leaves which grow from the sides of the trunk shortly after germination. These two strap-shaped leaves continue to grow for the rest of the plants life, from the base of the leaf. The leaves also posses many grooves and blind ends, as well as stomata along the top of the leaf, which allows the plant to collect water from the morning fog.

Welwitschias live for 500-600 years.

Playing dead

Just read a neat paper on the heritability of death feigning and how it may be selected for in the wild by Miyatake et al. (2004). Death feigning is when a creature pretends to be dead, either by falling off a twig and curling up its legs, or by freezing, presumably to escape predation. The gray death-feigning beetle pictured above can feign death for up to thirty minutes (according to the beetle dealer). What Miyatake and the others wanted to know was, is this death-feigning ability heritable, and does it actually help them escape predation?

So they took 200 red flour beetles and recorded how long they played dead for after touching them with a stick. The 10 males and 10 females who feigned death the longest were used to start a long line, and the 10 males and 10 females who feigned death the shortest were used to start a short line. They then repeated this procedure for ten generations, allowing only the 20 longest feigners and 20 shortest feigners to reproduce each generation.

After ten generations, they found that the long line feigned death for a longer period of time than the short line did. The long line feigned death for over a minute and a half, while the short line only feigned death for about 5 seconds. They also found a difference in the numbers of individuals who actually feigned death. What they saw was 86% of the long-line individuals feigned death, while only 7% of the short-line individuals feigned death.

So now they know that death feigning is heritable and can be selected for or against in nature, but does it actually work to help save them from predators? Will it actually be selected in nature? To find this out, they introduced a predator and recorded survivorship and behaviors of short-line and long-line individuals. What they found was that the jumper spider used as a predator would lose interest in the beetle if it feigned death. So most of the long-line individuals survived (64%), and most of the short-line beetles were eaten (73%).

So if the beetles have predators in an area that act like the jumper spider, you could expect that the beetles in those areas would have long death-feigning times, but in other areas without such predators, you may expect shorter feigning times. Now all you have to do is go out and test that!

Takahisa Miyatake, Kohji Katayamat, Yukari Takeda, Akiko Nakashima, Atsushi Sugita and Makoto Mizumoto. 2004. Is death-feigning adaptive? Heritable variation in fitness difference of death-feigning behaviour. Proceedings of the Royal Society B. 271: 2293-2296

Photohunter: Wrinkled Frogfish

This is one of my favorite fishes, the frogfish. They are related to the anglerfishes and have a lure to entice little fishes, like true anglers. Unlike the other anglers these guys are found in deeper waters hanging out on reefs, but not as deep as the true anglers who are also pelagic. Also, they are not ones for swimming. Their fins have an elbow-like joint which allows them to climb on the reefs. Apparently, they can jet-propel themselves by sucking in water and pushing it out the small gill opening behind the second set of fins [1]. They can glide for a good distance before settling on the reef.

They are ambush predators, lurking on the reef looking like a lumpy rock or sponge. An unwary fish may settle next to them, or be attracted by the small waving lure... then snap. The frogfish can expand its mouth and guts to a considerable degree and swallow fish almost as large as itself [1,2].

Life Photo Meme: Smart Slug

Kingdom: Animalia

Phylum: Mollusca

Class: Gastropoda

Order: Nudibranchia

Family: Facelinidea

This is the nudibrach Hermissenda crassicornis. While it may not look like much, when I look at it, I think 'smart'. H. crassicornis has often been used as a model animal as it is a great thing to study if you want to learn how memories are formed. They have a very simple nervous system, simplified to the point where every neuron has been mapped and named. Additionally, they can be conditioned to respond in certain ways when presented with a stimulus (much like Pavolv's dogs). Put that together with the ability to follow impulse along the nervous system, and you can 'see' how the slug reacts normally to a stimulus, then see how the route changes after you condition them. They've actually found out where memories are stored in these guys! If you want to learn more about learning check out Blackwell, 2006 for a review on the subject.