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A chart of rainfall depth by month.
Mole-rats burrow only after a rainfall of at least 15 mm over seven days when the moisture has reached burrow depth. Rainfall meeting these conditions at Dordabis, located in southern Africa, where Damaraland mole-rats are found, is shown here from January of 1988 through December of 1993, demonstrating the limited occasions for burrowing (Jarvis et al. 1998).

Reproductive suppression and incest avoidance

Both H. glaber and C. damarensis experience a great reproductive skew , meaning only a few members of each species ever achieve reproductive success. This is part of the definition of eusociality. For naked mole-rats, less than 1% of the population ever reproduces, and for Damaraland mole-rats less than 8% ever reproduce (Jarvis et al. 1994). This begs the question of how these two mole-rat species suppress reproduction. The current belief is that naked mole-rats and Damaraland mole-rats suppress their workers through different mechanisms.

Testing the aridity food distribution hypothesis

Using fractal dimension , which measures to what extent the burrow fills the area (Le Comber et al. 2002), Sichilima et al. (2008) investigated assumptions of the Aridity Food Distribution Hypothesis in Fukomys mechowii, a cooperatively breeding species of mole-rats. They examined burrow fractal dimension differences between the rainy season and the dry season, the relationship between fractal dimension and the number of colony members, and the relationship between fractal dimension and food mass in the burrow. They found that burrow fractal dimension increased with the number of colony members and during the rainy season, and that burrows with higher fractal dimensions had more food. This gives substantial support to the Aridity Food Distribution Hypothesis because it indicates that digging and burrowing is limited by energy demands during the arid season, one of the assumptions of the hypothesis. In addition, the risks of failing to find the patchily distributed food sources are reduced by greater numbers of foraging colony members (Sichilima et al. 2008). Similarly, Lovegrove and Wissel (1988) found foraging risks for solitary individuals in an environment with widely dispersed resources are high. Lovegrove also found, using math-based models, that the shift from solitary to group living is expected when there is a depression in the food density, which occurs when shifting from a mesic , or moderately moist, environment to an arid one (Lovegrove 1991), which falls in with the Aridity Food Distribution Hypothesis.

Naked mole-rats have no incest avoidance mechanism, unlike Damaraland mole-rats. Without those mechanisms there is no reason why workers should not breed with each other, yet they do not, suggesting that something must be preventing them. One possibility is that the queen shoves her workers (see [link] ), especially the larger ones who are more likely to breed eventually, to suppress reproduction (Jacobs and Jarvis 1996). Another is that some chemical or other social signal is given to suppress reproduction. Despite not knowing how exactly it is accomplished, it is known that when reproductively suppressed female mole-rats are removed from their colony and kept singularly their reproductive suppression is reversed (Faulkes and Abbott 1993, Clarke and Faulkes 1999). Since H. glaber do not avoid incest on their own, reproductive suppression is the sole method for maintaining the reproductive skew.

Questions & Answers

What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Mockingbird tales: readings in animal behavior. OpenStax CNX. Jan 12, 2011 Download for free at http://cnx.org/content/col11211/1.5
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