Dubia food for thought Q's

[JeffreH]

A great scientist is not a person who gives the right answers, he is the one who asks the right questions. Encouraging some debate and thought is always okay in my book! = )

Could a person get a Dubia to live for 5 years? Maybe even 7?

Heh, probably not, but certainly a good thought! We could maybe increase longevity by a few months or some percentile. There are predetermined limits to most animals. Think humans briefly. We have increased our population from a meager 1 Billion global count in 1800 to some 7 Billion at current. Despite current advances in technology, it is very unusual to have someone live to be 100 years old anywhere in the world naturally (and we've had BILLIONS come and go over the centuries). Looking at the deaths of all people, you can create a model to find the range of human longevity and can remain pretty confident that 99.99% of the population will not exceed X age ever by normal death under normal conditions. Obviously, we humans are a little bit of an exception... it wouldn't surprise me if in the near future it becomes a trend to rear your own organs in vitro.

[qoute]Could the raising of the Dubia roach at lower temperatures for a long enough time result in an adaptation that allows them to thrive in less than tropical conditions? Maybe not a good experiment, but still much more food for thought.[/quote]
This may be a very interesting experiment to find the temperature limits to these guys, but it will only lead to acclimation. Actual adaptation requires lots and lots of time. Organisms can acclimate quite quickly to new environments within some range. For example, I can walk outside with a T-shirt and feel comfortable at 50 degrees F, but someone who has acclimated to Florida's climate may find this very chilly.

Actual adaptation requires a change in the genetic expression through generations; essentially following the laws of natural selection. Everything in life is dictated by enzyme kinetics: if one roach happens to pop up whose enzymes peak productivity is lower than the others and the environment is cooler, they will have a greater chance of survival and therefore and opportunity to pass on these genes to their offspring.

In acclimation, there are limits as well. In humans, our peak enzyme efficiency occurs at 37 degrees C. It just so happens that this is our normal resting body temperature. If you deviate from this range, enzyme kinetics suffer. Increase temperature and you increase the rate at which substrate can be processed, but increase the temperature just a bit too much and you begin to denature the proteins. On the flip side, too cool of temperatures results in slower substrate processing by enzymes which makes metabolism and other bodily functions slower.

Imagine a graph... we'll call it the graph of Blaptica dubia's fundamental niche. Temperature may be a variable on the X axis, then you may have something like humidity on the Y axis. You can continue to add dimensions to this graph until you essentially get a football shape of plots. Each plot represents an insect that survived its entire lifespan and reproduced. Each dimension will have another key variable that contributes to the survivability of the species. I know this is hard to visualize, but bare with me.

In this graph, you may see a cluster of points in the dead center that match with say, 60% humidity, 85 degrees F. As you deviate from this range, you increase mortality ever so slightly until eventually you find the limits. The limits in temperature for B. dubia for example are probably around 75-100 degrees F (for both reproductive fitness and survivability). As you breach this range or approach the edges, you increase mortality. No matter what we do, we can NEVER get this cockroach to breed at 60 degrees F or be able to survive 120 degrees F in our lifetime. They can acclimate to minor fluctuations of a a few degrees, but nothing significant. They've evolved over hundreds of thousands of years to meet the needs of their normal niche.

Offspring being more nutritious at birth is an interesting thought. Some species actually provide a meal to their offspring with an afterbirth secretion (usually very unpleasant looking, lol). I'd wager so long as the female has been given quality gutload throughout her time, the offspring will reap the most benefits. Insects really don't store a lot of things though.. it isn't really their nature to do so. I'm still unsure as to whether rearing a nymph on one gutload vs another influences nutritional value after a long period of time or whether following the simply 24-48 hr gutload window is still the best all-around.

I've been DYING to do some nutritional analyses of varies feeders under varieties of conditions and being exposed to different gutloads. The information out there now is so vague... are these values based on just the insect, or insect + stomach contents? What are the actual calorie compositions from fat and protein, rather than just the % composition? What other goodies are in each feeder other than just the basic printout of Protein, Fat, Ash, Moisture, and Calcium? All good info, but there is so much more to be explored!