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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

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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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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