How far do bugs fly?

[campfire]

I was camped on Elizabeth Ridge a few weeks ago and got to contemplating the geography of the area. The streams on the west side of the ridge drain to the Great Basin by way of the Bear river. The streams on the east side of the ridge drain the the Pacific by way of the Blacks fork, I believe the Sweetwater, Green and Colorado rivers. So native cutthroats on either side of Elizabeth Ridge though only a few miles apart are of different straines because they might as well be contenents apart as the water never mixes. Now my question is: Does the same hold true to other aquatic life? Are there different strains of aquatic insects in different drainages or are insects that have flying adult stages able to cross drainages and carry their genes with them?

[Taxon]

Are there different strains of aquatic insects in different drainages or are insects that have flying adult stages able to cross drainages and carry their genes with them?

campfire-

Yes to both parts of your question. Aquatic insects, most orders (of which) are strictly terrestrial in their adult lifestage, display widely varying differences with regard to length of flight period and strength of flight.

For example, mayflies are relatively weak fliers, and have an extremely short flight period. On the other hand, dragonflies have an extensive flight period, and are extremely strong fliers.

So, this means that, generally speaking, natural barriers to migration, an extreme example of which would be the continental divide, would be more likely to impede the migration of a mayfly species, than it would be to impede the migration of a dragonfly species. Of course, another important factor limiting migration, would be intolerance of a particular aquatic insect species to habitat variation.

As the result of these and many other factors, some N. American species are extremely localized in their distribution, whereas others are widely distributed, and of course, the vast majority would fall somewhere between those two extremes.

Hope this answers your question.

[campfire]

Thank you Taxon! I knew someone here could answer my question. There are a lot of knowledgable folk that frequent this site. I guess that explains why one pattern works well on one side of the mountain and another works better on the other side. Thanks again.

[Lonnie]

Campfire,

Another thing that Taxon didn't mention is that Entomologists/taxonomists in many cases are still wrestling with genera and species level questions and until these issues are sorted out, it can be difficult to answer some of the population level questions.

In population genetics there are 4 basic measures of genetic variability.

Variation Within individuals. This is basically how many different copies/types of genes a single individual has. (most organisms have more that one set gene that codes for a particular protein.)

Variation between individuals This is a measure of the genetic diversity of the total population of organisms.

Variation within sub-populations. This is similar to above, except we are looking at the variation between individuals within a sub-population (breeding group) instead of the entire population.

Variation between sub-populations This measure compares the total variation within sub-population to other sub-populations.

So based on these measures the genetic diversity of a species can be broken up several way. The distribution of this diversity depends alot on breeding strategy and local adaptation that a particular species has adopted. It is also why conservation of genetic diversity can be difficult in small populations, if say for example, those organisms are ones whose evolutionary survival strategy is to hold their genetic diversity at the population or sub-population level (as opposed to the level of the individual...)

EDIT: SO re-reading I don't think I answered your question. I can't REALLY speak for insects, as I haven't looked at their literature, but I know for fish (in this case trout), that most of the genetic variation is BETWEEN populations (The is not that much genetic diversity within a single population, but lots when you look at the TOTAL population. This is most like a result of inability of these populations to interbreed and local adaptation). At talks I gave when I was still in school, I had some entomologists talk to me about my research and said that they saw similar patterns to mine in organisms they studied (mainly water striders).

http://www.google.com/search?hl=en&safe=active&q=population+genetics+aquatic+insects+trichoptera

http://www.google.com/search?hl=en&safe=active&q=population+genetics+aquatic+insects+ephemeropter a&btnG=Search

http://www.google.com/search?hl=en&safe=active&q=population+genetics+aquatic+insects+odonata

[campfire]

Campfire,

Another thing that Taxon didn't mention is that Entomologists/taxonomists in many cases are still wrestling with genera and species level questions and until these issues are sorted out, it can be difficult to answer some of the population level questions.

In population genetics there are 4 basic measures of genetic variability.

Variation Within individuals. This is basically how many different copies/types of genes a single individual has. (most organisms have more that one set gene that codes for a particular protein.)

Variation between individuals This is a measure of the genetic diversity of the total population of organisms.

Variation within sub-populations. This is similar to above, except we are looking at the variation between individuals within a sub-population (breeding group) instead of the entire population.

Variation between sub-populations This measure compares the total variation within sub-population to other sub-populations.

So based on these measures the genetic diversity of a species can be broken up several way. The distribution of this diversity depends alot on breeding strategy and local adaptation that a particular species has adopted. It is also why conservation of genetic diversity can be difficult in small populations, if say for example, those organisms are ones whose evolutionary survival strategy is to hold their genetic diversity at the population or sub-population level (as opposed to the level of the individual...)

EDIT: SO re-reading I don't think I answered your question. I can't REALLY speak for insects, as I haven't looked at their literature, but I know for fish (in this case trout), that most of the genetic variation is BETWEEN populations (The is not that much genetic diversity within a single population, but lots when you look at the TOTAL population. This is most like a result of inability of these populations to interbreed and local adaptation). At talks I gave when I was still in school, I had some entomologists talk to me about my research and said that they saw similar patterns to mine in organisms they studied (mainly water striders).

http://www.google.com/search?hl=en&safe=active&q=population+genetics+aquatic+insects+trichoptera

http://www.google.com/search?hl=en&safe=active&q=population+genetics+aquatic+insects+ephemeropter a&btnG=Search

http://www.google.com/search?hl=en&safe=active&q=population+genetics+aquatic+insects+odonata

Lonnie,
This is exactly the basis for my question. The interbreeding of fish is limited because they are water bound and water allways runs down hill. But at the headwaters of drainages even continental drainages are very close. It might be in the relm of possibility for aquatic insects to fly from one drainage to another taking their gene pool with them provided (as Taxon pointed out) that their flight stage is long and strong enough. Now if I understand you correctly, such interbreeding would decrease the genetic diversity between populations. Right?