Ant-mimicking spiders

Believe it or not, this is a spider, not an ant.

Ant-mimicking jumping spiders (Salticidae) lure their prey into a false sense of security. Wikipedia Commons.



Take the Leap: One Extra Day, Three Ways to Enhance Your Blog

Check out this blog post. Very useful for me as a new blogger but also for those more experienced who may have run out of ideas…

This year, February is a day longer — let’s use it to make our blogs better.

Source: Take the Leap: One Extra Day, Three Ways to Enhance Your Blog

Discover: The Best Content Across WordPress

The Daily Post

Bloggers do incredible things on their sites: they share powerful stories, poems, and essays. They amaze us with their photography, illustration, and other creative projects. Sometimes they just speak directly to us, the readers, in a way that is so moving that their voices stay with us for days (if not more).

Since 2009, we on the team have highlighted the strongest posts we could find on Freshly Pressed, a showcase of the very best of the blogosphere. Six years — and almost 15,000 posts — later, we couldn’t be prouder of the community of bloggers and readers that has formed around it.

Many of you have followed Freshly Pressed for years, and we’re grateful for your readership! This week, we’re retiring Freshly Pressed, with Discover replacing this tab in your Reader.

Just like the slickest theme from 2009 might start to show its age by 2015, though, so did Freshly Pressed. Which is why we’re thrilled to…

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Begging signals are honest in mimic poison frogs

I know many children who bug their parents incessantly when they want something. A new pair of trainers that all the cool kids at school have. A newly released computer game, which is far better than the one released last week. Perhaps a tasty chocolate treat before dinner? I’m sure many of us have been guilty of this at some point, and we hope our poor parents have since forgiven us.

But can we honestly say that we really needed those things that we begged so much for?

This puzzle also applies to begging in young animals. An obvious example is a nest full of the brightly coloured open mouths of hungry chicks. These begging signals stimulate food provisioning by parents that, by preventing starvation, ensure their young survive and pass on their own genes to future generations.

But parents have to balance their offspring’s needs with that of their own, because feeding young is costly. They expend precious energy finding the food, make themselves vulnerable to predators, and they are unable to eat the food themselves – a high price if food levels are already low.

Because of this dilemma, parents will lower how much effort they put into feeding their young if they think that they’re not really hungry.


A nest of begging carrion crow (Corvus corone) chicks. Wikipedia Commons


The begging signals of hungry young therefore have to make the parents truly believe that they are hungry. That is, they have to be reliable signals of need. They have to tell the parents that: “I am truly hungry and if you don’t feed me I will die and therefore your genes will not survive” or something similar. Begging will only persist in nature if this occurs – as an “Evolutionary Stable Strategy” (ESS) – because otherwise the benefits of begging would be lost.

Over the years, three main hypotheses have been suggested about how the reliability of begging signals is achieved.

These are:

  1. Begging intensity reflects offspring need.
  2. Begging is costly.
  3. Parents provide the correct amount of food in accordance with offspring need (1).

A study published in Animal Behaviour today has tested these hypotheses in the tadpole offspring of mimic poison frogs, Ranitomeya imitator. In a series of experiments, the study by graduate researcher Miho Yoshioka and Professor Kyle Summers at East Carolina University found evidence for all three of these hypotheses.

Mimic poison frog (Ranitomeya imitator). Wikipedia Commons

The team found that:

  1. Tadpoles that were given less food increased begging behaviour = signalling need.
  2. Tadpoles that were experimentally made to beg by the researchers suffered a cost (e.g. showed slower rates of growth).
  3. Parents were more likely to feed tadpoles that were fed a non supplemented diet as opposed to siblings fed a supplemented diet.

The researchers conclude that begging signals in R. imitator are honest and may predict differences in degree of parental food provisioning to offspring.

So, next time you ask your parents for something you don’t absolutely need… think again. You might actually ruin your chances of them getting you something you really do need.