Posts by Alistair Wilson

Although it's not completely obvious in the photo,  it looks like there is a spine near the back end of the abdomen which is a characterisic of hawk moths, and assuming you are in the UK (or at least Western Europe), then I would take a stab at this being the larva of the elephant hawk moth, Deilephila elpenor.

There is actually lots of info on wolf-dog hybrids here:
http://en.wikipedia.org/wiki/Wolf-dog_hybrid

I for one had not realised that people were deliberately hybridising them quite so often.

Just to add - we basically have two copies of each (nuclear) gene as we inherit one from each of our parents. So in your example -

Any individual has two copies of the PAH gene but they may or may not be exactly the same version (i.e. allele). Between alleles there are slight differences in the sequence of the DNA that may, or may not, translate into functional differences.  In the whole population there are >500 different versions (alleles) to be found but each individual can have (at most) two of these.

Is this really a bug?
Looks to me more like a strange dashboard ornament (possibly made from/to look like a dried out shrimp?!?). If this is actually a living animal I'd be very curious to know how it walks, let alone what it is!

Unfortunately we can rarely identify insects from a verbal description. If you see another one try and get a photo to post (and tell us where in the world you are).

In the mean time google "Ichneumonid wasp" which would be my best guess, and see if it may have been a species from this group. For info the "sting" was almost certainly not a sting, but rather an ovipositor used for depositing eggs.

Starting post-doc salary for biologists in the UK is (currently) normally about 29K I think. You can see some down as low as 26K and some as high as 32K (maybe even more if its a position funded by someone like Welcome as opposed to the research councils).

In a university setting progression upwards from here is partly a matter of hanging on in (i.e. you progress up a pay scale according to experience, but staying in acadaemia is competitive so there is wastage along the way), and partly a matter of getting promoted (which requires landing grants, publishing papers, teaching etc). To my mind the financial reward is pretty fair - it is not equal to what you can earn as a doctor - but all of us do science for love not money.

Peter's post made me think of something potentially important here.

It is actually quite common for predators to "play with their food". Watch any domestic cat that has cornered a mouse of bird and you'll see it happening. However, I'm not sure that we can really say that this is for "fun" which is obviously a human idea. "Play" is a way to learn and practise hunting skills, whether or not you want to say an animal also enjoys it depends on how far you are willing to accept/believe/argue that an animal's emotions can be stated in such human terms.

As another example there is also some great footage about of dolphins killing porpoises and appearing to "play" with them in the process. This is again thought to be functional behaviour in the sense that it gets rid of competitors (porpoises and dolphins both eat fish) and provides an opportunity for younger individuals to practice hunting/killing skills. To me it also looks like they are also having fun... but that may be just a human perspective (and is probably based in part on shape of a dolphin's mouth which always reminds people of a human smile!)

Hi Nicola,
I'm sorry but nobody seems able to help with this one. nice photos though!

Sorry that nobody seems to have the answer to this.

I had wondered about the predatory bush cricket, Saga pedo, although I am no entomologist and this is an eductaed guess based in part on how big it is. I haven't been able to find out if Saga is on Rhodes either. Sorry we can't do better.

>Note that the small freshwater 'sharks' commonly sold in pet shops are not actually sharks, but usually a form of Minnow.

...and just to add that although small compared to real sharks, some of these freshwater fish like the Bala shark Balantiocheilos melanopterus, and red-tailed shark Epalzeorhynchos bicolor actually grow rather large for tropical fish and are probably not ideal for inexperienced fish keepers. They can and do make good pets provided you have a big enough tank and the knowledge of how to look after them.

Hi Vicki,
Unfortunately we cannot generally identify insects without a photo and even then it is hard and often impossible to give a definite ID!

If you can take a picture then please post it and also tell us where in the world your garden is as that would narrow things down considerably!

Sounds to me like you found some squid eggs  - if so they should have looked something like this:

http://www.askabiologist.org.uk/answers … hp?id=4324

This one comes down to what you mean by "large". The king cobra is considered the longest venomous snake in the world, but it is quite a slender snake and so probably not as heavy as some others (e.g. bushmaster).

Also bear in mind that snakes are variable in size within species, just as people vary in height and weight. Based on the longest specimens ever found, the King Cobra wins. Whether the average length of all king cobras is greater than that of all bushmasters I don't know.

Glad (and somewhat surprised) to hear I got it right given that I’ve only been to Florida once.

Below is some further information (and a photo) sent in by Sean in Australia on a closely related species - Lutjanus argentimaculatus. Sean also makes an excellent point about common names for fish. I am not sure why, but it is definitely the case that common names for fish have more local variation than other taxa. Just to add to confusion many fish are also renamed before being sold in fishmongers/restaurants I suppose because “dogfish” sounds unappetising but people will pay good money for “rock salmon”

From Sean:

“I was actually hoping to add some enlightenment to the
'unknown saltwaterfish' that Daniel Harris was uncertain of regarding its identification. I was actually surprised that someone was so unaware of a fish species that I thought was reasonably well known. I'm from Australia, and it is a popular fish caught generally in estuarine waters across much of our northern coastline. We call it the Mangrove Jack (Lutjanus argentimaculatus ....sorry for the lack of italics!). One significant point I DID learn was that the genus Lutjanus is quite cosmopolitan. Typical of common names, I am aware that what you call a 'jack' in the US we call a trevally, and the name 'snapper' is applied to such a diversity of fish species the world over that the name is beyond accuracy in an attempt to classify it. Anyhow, I've included a photo of the Mangrove Jack I recently caught off the NW Australian coastline. They are an attractive fish, a tremendous fighter and great eating (though we encourage only keep what you can eat in one sitting)!!!”

That may be tricky depending on exactly what species you have there. This website may help - although it is aimed at a UK audience so not ideal.

http://www.eggcase.org/default.asp?home=1

A good field guide should include egg cases too. You might also try this site
http://www.sharks.org/teachers.htm
which includes teaching materials, and possibly contact details for a shark expert in your area!

It is true that jackdaws  - like a lot of corvids - are pretty monogamous, and there have been a few genetic studies that have failed to find evidence of EPP (extra-pair paternity). Having said that I would never say never!

So it would be fair to say that although we have looked for it, we don't have much evidence for extra-pair coulations in jackdaws (relative to many other passerine birds). My interpretation of this is that EPP rates arecertainly low, although I would hestitate to say they are absolutely zero.

Basically no, it's not possible to cross-breed spiders. There  are probably a few exceptions since species integrity can be a bit fuzzy at times. For example I've seen reports of hybridisation among closely related species of house spider

http://www.bioone.org/doi/abs/10.1111/j … 07.00146.x

and I am sure there are other groups where this occurs. The key is that if hybridisation does occur it will always be with very (genetically) similar closely related species. It's this rather than size that is the limiting factor!

Having said that it would be possible - at least in principle to genetically engineer spiders - and put bits of the DNA from one species into another. I can't see any obvious utility in doing that though (and it would be expensive research!) so sadly (or perhaps happily) it seems unlikely that a mad scientist
anywhere is working away at this particular project.

Hi David,
It's a sawfly. Someone beat you to it with this question by a couple of days so look here for more - 

http://www.askabiologist.org.uk/answers … hp?id=4295

Hi Kimberley,
If you put "marine biology" into the Ask a Biologist search box you'll hopefully find some useful advice in teh replies to similar questions. Do post again if you have further question though  - in which case it would be useful to say where you live (i.e. there is no point in us recommending a course in the UK if you're actually American).

Probably whichever was bigger (which - on average - is  more likely to be the tiger shark).

I would think it is mostly to do with aggression between the fish - basically when they bump into each other or attempt to bite each other they will sometimes turn their body position so that you see the flash of silver from above.

From the point of view of avoiding predation this is obviously not that clever, but there is more to stickleback life than predators. Fish also need to compete with each other for territories, mates, food etc. Especially at this time of year when the males are building and defending nests aggression is pretty common.

Cephalopods (squid, octopus, cuttlefish) have blue blood since they use haemocyanin to bind oxygen rather than haemoglobin (which vertebrates use and which is red). From memory I think most molluscs use haemocyanin (in which case the blood of winkles, mussels etc is presumably blue too).

My understanding is that the mutation rate in the ganetic line is considerably higher in males (in humans), and that this was thought to be largely a consequence of the relatively higher number of cell divisisions in spermatogenesis as compared to oogenesis.

However - while I can see that an individual sperm has a higher probability of carrying a mutation than an individual egg, it must also be the case that it has a lower probability of forming a zygote. Consequently it is not clear to me that a nove mutation carried in a human child is mre likely to come from the father than the mother - although perhaps the numbers do work out this way?!?

With regard to contemporary global warming, there is a bit of dispute about the evidence for adaptive evolutionary responses. Certainly lots of traits are changing in a way that seems adaptive. For example, many birds are laying eggs earlier in the year which seems sensible given that the limiting factor for raising a clutch is often food (e.g. caterpillars). If spring comes earlier then birds need to shift forward their breeding time to match the earlier peak food resource.

However, nearly all traits are determined by both genes and the environment, so in a sense if the environment is changing (which it obviously is) then it is inevitable we will see changes in traits too. To really demonstrate the evolution is occurring we need to see if gene frequencies are changing through time, in a way that matches our predictions due to selection being imposed by global warming. Although a lot of biologists are working on the genetics of wild population this is actually a tough challenge (technically and statistically) and at the moment my personal view is that good evidence is scarce .

To sum up - 1) global warming is imposing selection for change, 2) many populations are showing trait change consistent with an adaptive response but for which there are other potential explanations, 3) actually demonstrating a genetic response to selection in a wild population is very hard, but (I think) will become a lot easier in the next few years as genomic approaches become more readily applied to ecological study organisms.