WEEK 2 - traumatic insemination and sexual conflict in the bed bug cimex lectularius STUTT AND SIVA-JOTHY 2001

Question 1

Authors

Answer 1

stutt and siva-jathy 2001

Question 2

background why is the bed bug unique in sexual copulation?

Answer 2

unique mode of copulation termed traumatic insemination

Question 3

what is traumatic insemination?

Answer 3

the male pierces the female abdominal wall with his external genitalia and inseminates into her body cavity

Question 4

what did stutt and siva-jathy 2001 do?

Answer 4

controlled insemination of bed bugs where it was allowed to be frequent and restricted to see what costs traumatic insemination has on females

Question 5

what do the results of stutt and siva-jathy 2001 show?

Answer 5

that experimental females did not receive indirect benefits from multiple matings

Question 6

what do the results of stutt and siva-jathy 2001 show for the first time? (3)

Answer 6

last male sperm precedence
suboptimal remating frequencies for the maintenance of female fertility
reduced longevity and reproductivity success in females

Question 7

what do stutt and siva-jathy 2001 conclude?

Answer 7

traumatic insemination is probably a coercive male copulatory strategy that results in a sexual conflict of interests

Question 8

why do sexual conflicts occur?

Answer 8

becasue of the potentially different fitness optima for each sex resulting from copulation.

Question 9

what are some examples of over what sexual conflicts could occur? (4)

Answer 9

isogamous and ansiogamous reproduction
copulation duration and mating frequency
relative parental investment
copulation costly to one partner because of adaptations in the male that are associated with sperm competition

Question 10

what is a well studied example of sexual conflict?

Answer 10

sperm displacement in Drosophilia melanogaster

Question 11

D.melanogaster is ______. Males are able to transfer ____ within the ejaculate that act to disable and kill the ____ of rival males.

Answer 11

polyandrous
proteins
sperm

Question 12

Clark et al 1995 found that male success in sperm competition in d.melanogaster is in part determined by what?

Answer 12

the transfer of the proteins in the ejaculate

Question 13

the proteins transferred in the ejaculate of d.melanogaster as well as determining the success of sperm competition for males impact the females how?

Answer 13

toxic to the female and reduce female longevity and fitness (chapman and partridge 1996)

Question 14

Rice 1996 said what has occurred in d.melanogaster due to the proteins in the ejaculate?

Answer 14

sexual conflict resulting in a co-evolutionary arms race between the sexes

Question 15

the results of stutt and siva-jathy 2001 show a measurable fitness cost to females from natural patterns of traumatic insemination, what is the cost and what does this provide evidence for?

Answer 15

cost: females from the group which had more copulations (5 vs 1) had a significantly higher death rate
evidence: the conditions for a sexual conflict over the mating frequency are present

Question 16

why does frequent remating by male bed bugs occur?

Answer 16

in part because of the pattern of sperm precedence favours the last male to copulate

Question 17

what may have provided male bed bugs with the opportunity to avoid female adaptations that control copulation frequency?

Answer 17

the evolution of an intromittent organ that bypasses teh normal reproductive system

Question 18

what do the results from stutt and siva-jathy 2001 indicate about the LRS of female bed bugs?

Answer 18

females need to copulate only approximately 1 in every 4 blood meals to maximise LRS but the normal copulatory rate (20x optimum) results in females suffering reduced longevity with no benefit of egglaying

Question 19

what does theory predict about the sexual conflict seen by stutt and siva-jathy 2001 between bed bugs?

Answer 19

theory predicts that regardless of the mechanism females should evolve counter adaptations to the costs of multiple insemination. yet bed bugs show no mechanism, however there are hypotheses about the mesospermdege such as that it functions to kill sperm, or to protect the female from infection due to traumatic insemination (as predicted by stutt and siva jathy) but these all remain to be tested