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Mating interactions are prime arenas for adaptation/counteradaptation, since they often involve a conflict of interest between the sexes. Males evolve traits that promote their confidence in paternity and sperm viability, while females develop mechanisms for selecting only optimum sperm (sexual selection)(Siller 2001). While sexual selection is easily recognized before mating (females choose to mate with males who display attractive characteristics and/or fitness indicators), it can also occur post-insemination through sperm ejection or a mechanism called cryptic female choice-the differential selection at the hidden level of the gamete(Eberhard 2000). Cryptic female choice can be passive, as when eggs are fertilized by sperm that win the “race” to the gamete. Or, the choice can be active: a female’s sperm storage system can be designed to give priority to the last sperm she receives, allowing her to annul the representation of previous mates if she meets a superior male (Eberhard 2004).

One intriguing example of cryptic female choice exists in Australian redback spiders. The female redback has developed multiple sperm storage sites, which promote post-copulatory sperm management by the female. The male has two palpal emboli, so he could potentially inseminate both sites (the fitness optimizing strategy for males), but the larger female can physically control where the male injects sperm (in one or two sites, or in an empty site versus one occupied by previous males’ sperm) (Andrade and Snow 2005).

The male redback thus appears at a disadvantage for two reasons. Firstly, if he manages the rare deal of finding a mate, his control over paternity is minimal. Also, if takes more time to inseminate two sites as opposed to one, and females usually cannibalize doubly inserting males before copulation is complete (Andrade and Snow 2005). Thus, the male redback has developed an important counteradaptation: a constriction of the abdominal exoskeleton during mating that protects male organs from wounds inflicted by the female mandible. In one study, males displaying constriction had improved survival, heightened physical endurance, and greater mating success with new males (Andrade and Snow 2005). Multiple sperm storage units in females and the constriction mechanism in males illustrate how mating interactions can disproportionately benefit a single sex, driving a progression of counteradaptations.

The question of female fecundity benefit

Even a conflict of interest hypothesis, a claim that females gain disproportionate benefits from eating males, is insufficient to explain the majority of sexual cannibalism cases. The behavior is prominently observed in spider species that are highly sexual size dimorphic , such as wolf spiders. In contrast with mantises, male spiders are frequently diminutive compared to females. The consumption of male bodies can contribute little substance to the mother’s nutrient store, so cannibalism does not measurably increase female body condition or ootheca mass (Wilder and Rypstra 2008). If female fecundity does not increase from sexual cannibalism (which obviously precludes the male from gaining fitness), then how can this behavior have evolved? Perhaps there is a context in which males alone profit from their own self-sacrifice.

Questions & Answers

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
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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.
Bharti
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
Daniel
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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
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
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
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.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket 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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