Week 10 Flashcards
What does A.M. Leroi suggest about all known genetic diseases?
They have a signature visible in the face.
-He wrote Mutants, the lagoon –> a book about macromutations
Why might sexual conflict drive rapid evolution?
Differences in optimal time, location, or frequency of mating leads to evolutionary “chases”, or “arms races”.
- Adaptation and counter adaptation between sexes operates on different loci in each sex.
- traits affected associated with sexual selection, reproductive physiology/morphology.
What is the dimorphism in yellow dung flies?
Mating tactics?
Males are bigger and more aggressive (unusual in invertebrates)
- Females would mate with one male, first male would deseminate and then second male would come along to fertilize her.
What is the evidence of sexual conflict in water striders?
Males have hooks that “grip in” to seams on females head; it is engineered to secure male and prevent female from deseminating him (nonconsensual)
What’s so special about G. gracilicornis females?
They CAN control clamped male from mating with her –> The females won the arms race.
-Have have concealed genitilia; covered by a shell.
-G. Lacustris LAC the shell.
Are there any ways the male can mate with gracilicornis females, despite the presence of a shell?
They “sing” a love song.
- Tap the water in a rhythmic way
- Only found in super obscure places like Korea.
What was the experiment that male water striders attract predators (by tapping) to intimidate females into copulation?
Used a y-shaped arena.
- One side contained male w/ normal female
- Other side contained male with female equipped with bar.
- -This male could not tap the water.
A predator was present on the bottom of the Y
-Predator always went to the signalling side; putting her at risk because she’s on the bottom and he’s on top.
What is the sexual conflict in Giant diving beetles?
Males use special suction cups to grip females and mate-guard after copulation.
- Females in some species have evolved apparent defenses in reply
- Grooved elytra supposed to reduce adhesion
How did Green et al study the polymorphism in female giant beetles?
Made a tensometer –> measured the force needed to remove suction cup from female.
- MEasured the roughness of slytra and pronotum
Why is there selection for traumatic mating in bed bugs?
- Anchoring of male during copulation
- Fecundity stimulation
- Direct injection of Sfps more effective
- Stimulates “terminal investment strategy”
- - “uh oh my situation can only get worse from here (after puncturing female) I should just keep going” - As a transition to internal fertilization
- In broadcast spawners, individuals with targeted fertilization become favored. - Paternity benefits
- Circumvent selective environment of female repro tract
- In hermaphrodites, amy evolve to increase fitness as a “male”
What is the traumatic insemination of female bed bugs?
Sperm is transferred directly into body wall rather than using female genitalia
-Avoid female capacity to choose
What is a spermalege?
It is a unique organ seen in the female Cimicid bedbugs for receipt of sperm and seminal fluids.
- One sided: males try to chase down female, female will squeeze into position that exposes spermalege side.
What are the benefits of having the spermalege?
Normally, increased matings would decrease the lifespan in Cimicid bedbugs.
-If the male mates on the spermalege piercing site, the lifespan is not significantly altered.
Despite the traumatic mating being harmful, are there any side-benefits for the female bedbug?
The mating rate did not affect female lifetime reproductive success
-Male Sfps promoted higher daily fecundity of females
What did Reinhardt and Sive-Jothy find about male ejaculate components in insects?
- NORMALLY increased femae reproductive rates usually result in accelerated senescence.
- However ejaculate components were found to delay reproductive senescence while elevating female reproductive rate in an insect.
What do the results of Reinhardt’s experiment and the evolution of the spermalege mean for mating rate and fecundity in female insects?
Ones that receive high doses of sperm have greater R time before senescence.
-Data combined suggests that mating without spermalege WAS harmful but evolution of spermalege allows increased fecundity from high mating with males.
What two sexual conflicts do Macrostomum face?
Allocation to male versus female function.
- The Batemanian conflict of wanting to play male for as long as possible
- -> most energy efficient
What effect did Lucas Schaerer find regarding density on sex allocation?
Raised pairs (low density) yielded even ratio.
Octet pairs (high density) yielded greater bias for males
Effect of density on # of copulations?
Take worms and put them in a common environment.
-Copulation rate is higher in worms raised for octets.
What is the sucking behaviors of worms for?
What is the effect of density on sucks per copulation?
Sucking behavior is worm trying to dissinseminate (doesn’t want to be impregnated –> remove sperm by sucking) = favoring male function
- Low density increases sucks per copulation –> favor male function
Macrostomum have a very diverse life history for sperm transfer. What is the nature of sperm used in traumatic mating of Macrosomum?
The hypodermic mating strategy uses small smooth sperm.
Sperm with hooks and barbs is used for one way entry (through organ)
What is the mating practice of pulmonate snails?
If possible, they fire a “love dart” made of calcium carbonate or chitin into their lover.
1. They are attacked by projectile
2. anti aphrodisiac - and
increases egg laying
-Seems to influence either sperm uptake or remating frequency
-If animal is darted, cuases muscular constriction and sends sperm to where egg can be fertilized
-If male doesnt hit just right female wont get fertilized.
What is the sexual conflict in ducks?
Males are hypersexual –> forced copulation
-Females could be drowned by multiple males trying to mate
Ducks have corkscrew shaped penis VERY LONG
- Vagina is also corkscrew shaped but oppositely coiled male has to evert.
- Female also has blind pouches that force males to ejaculate lower down (less chance)
- Adaptations allow female to assert control over who gets to ejaculate successfully.
What are ejaculatory plugs?
Common feature of male ejaculate
- After mating, semen coagulates to clock the passage of further sperm through the female genital tract.
- Found in many insects, arachnids, rodents, reptiles, and other mammals.
- In primates the degree of coagulation is correlated with the probability of multiple mating
