<< Chapter < Page Chapter >> Page >
The complex social system known as eusociality is marked by cooperative care of young, overlapping generations, and distinct castes, like workers and breeders. It is found in a variety of organisms such as shrimp, social insects like bees and ants, and mole-rats. Eusociality is a case of kin selection, in which individuals find that helping a relative may provide more overall fitness for themselves than being selfish. In a eusocial society, workers relinquish most, if not all, of their breeding rights to help raise another’s offspring, usually closely related to them, thereby gaining indirect fitness. The mole-rat is an excellent example of how eusociality evolves, as not all species of mole-rats are eusocial. This evolution is best explained by the Aridity Food Distribution Hypothesis which accounts for the environmental constrictions of predators and scarce resources that make helping close kin more beneficial for one’s own genes than risking death in the harsh conditions. Evolution of eusociality has developed distinct tiers of breeders, workers, and dispersers who are essential for reproducing, foraging, and maintaining some genetic drift. The mechanisms behind how these tiers are maintained are not entirely understood, but appear to be a combination of physical factors such as verterbrate length and hormone suppression of reproductive behavior in non-breeder tiers.

Author: Sheena Shah-Simpson


Mole-rats (family Bathyergidae) are a type of rodent found in Africa. They live underground in burrows made up of different chambers for their nests, latrines, food storage areas, alongside chambers for foraging, in which they dig with their incisors and foreclaws. They eat roots, tubers, and bulbs. Most species of mole-rat are solitary, coming together only for mating. A few species, though, form colonies where many mole-rats live together in large complex burrows they have dug because it makes it easier to gather food and reduces predation risks.

Of the species that live in colonies, eusociality has evolved independently at least twice, in Heterocephalus glaber , the naked mole-rat ( [link] ), and separately in Cryptomys damarensis , the Damaraland mole-rat (Allard and Honeycutt 1992, Jarvis and Bennett 1993, Walton et al. 2000, Faulkes et al. 2004). Colonies in both species have three morphologically distinct castes. The first caste is made up of the breeders, usually one female “queen” and her one to three mates, who breed and encourage the workers in their daily tasks. The second caste is formed by the workers, usually mole-rats who are highly related to the queen. These workers are reproductively suppressed by their own hormones that are secreted due to social cues from the queen, keeping them working instead of reproducing. They take care of the offspring, forage for food, and patrol the burrows. The final caste is the dispersal caste, made up of mole-rats of a slightly larger build who act as workers until they leave the colony to either found or join another. The dispersal caste is virtually the only form of gene flow in these mole-rat populations since the colonies are usually separated by a large distance that is dangerous for mole-rats to cross above ground.

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
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
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Berger describes sociologists as concerned with
Mueller Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Mockingbird tales: readings in animal behavior. OpenStax CNX. Jan 12, 2011 Download for free at http://cnx.org/content/col11211/1.5
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Mockingbird tales: readings in animal behavior' conversation and receive update notifications?