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APS209 Behavioural Ecology > Pt. 2 > Flashcards

Pt. 2 Flashcards

1
Q

Natural selection: The … individuals will survive and reproduce, so succeeding generations will become … to their environment

A

fittest, adapted

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2
Q

The problem with the theory of natural selection is that it cannot explain … traits that … an individual’s chances of survival

A

costly, lower

(e.g. peacock tail increases chance of predation and energy expenditure to produce and carry, costly to preen and keep clean)

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3
Q

This problem can be solved by the theory of … …, which is when certain traits increase an individuals chances of …, even if these traits are costly.

A

mating

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4
Q

Two types of sexual selection are male-male … (… selection) and female … (… selection)

A

competition, intrasexual, choice, intersexual

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5
Q

… sexual characters are things that differ between the sexes, but have been selected for by … selection, e.g. genitalia, ovipositors

A

Primary, natural

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6
Q

… sexual characters are characters that differ between the sexes and are selected for by … selection, e.g. fighting ability, weapons, bright colouration

A

Secondary, sexual

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7
Q

Male moose have large … for display and ….

A

antlers, fighting

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8
Q

Male salmon develop a … jaw and … colouration during the spawning season.

A

hooked, red

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9
Q

What is the underlying basis for sexual selection? To answer this we have to look at the fundamental differences that define the sexes. In most sexually reproducing organisms, male and female gametes are … (known as …)

A

difference, anisogamy

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10
Q

Females produce few large costly …, males produce many small, cheap, mobile …

A

eggs, sperm

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11
Q

Anisogamy allows sexual selection to act…

A

differently on the two sexes

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12
Q

Males can generally fertilise eggs at a…

A

faster rate than females can produce them

  • shown by Bateman experiments on Drosophila
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13
Q

Bateman found, when looking at …, that the number of offspring did not increase after a female had copulated once, but did increase … as a male underwent further copulations. This shows that males have a higher … … rate than females. Males can maximise their reproductive success by mating with…

A

Drosophila, linearly, potential reproductive, as many females as possible (this is not true the other way around as females are limited by the number of eggs they can produce)

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14
Q

Sexual selection will select for traits that increase a male’s ability to find females and … with other males to copulate with those females, and will select for female traits that … between males and choose the … ones to fertilise her costly egg. This is how sexual selection can lead to …

A

compete, discriminate, best, dimorphism

  • males go for quantity, females go for quality
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15
Q

There is selection for females to remain … to protect them and … …

A

cryptic, their offspring

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16
Q

The most basic form of male-male competition is direct … contests between males, for access to mates. E.g. male elephant seals can weigh … and they fight vigourously (often ends in injury or death). The winner of the fight (beachmaster) has a harem of dozens of females. Other males get few or no matings.

A

physical, 2000kg

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17
Q

In elephant seals, the biggest factor that makes a male successful is … …. DNA analysis shows that mating success is linked to paternity, therefore there is tremendous selection pressure on male seals to … …

A

large size, grow large

  • largest males are more dominant and mate with more females
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18
Q

Some elephant seals do not attempt to grow large, and instead … copulations when females are in the …

A

sneak, sea

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19
Q

There is often more evolutionary pressure on … to become … to compete.

A

males, larger

  • not the same pressure on females
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20
Q

We predict greater sexual … in species where intrasexual competition is more …. Therefore we’d predict … species to show more dimorphism than … species. There is strong evidence for this in Pinnipeds (seals and sea lions)

A

dimorphism, intense, polygynous, monogamous

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21
Q

In Deer, monogamous species have males smaller … relative to … …, compared to polygynous species.

A

antlers, body size

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22
Q

Two important points to note:

A

Sexual selection doesn’t have to lead to sexual dimorphism, and sexual dimorphism can arise from processes other than sexual selection.

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23
Q

Huias were crow-like birds from New Zealand. The sexes had very different bills (females much longer and curved, males shorter and sturdier), despite both feeding on huhu grubs. This is because…

A

male bills were adapted to hammering into rotten wood, whereas female bills were adapted to extract food from holes and crevices in more solid wood. - occupying two different niches to avoid feeding competition between partners

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24
Q

It is often difficult to distinguish between male-male competition and … …

A

female choice

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25
Q

To separate mate choice and competition, you myst carry out careful experimental manipulations controlling for differences in … … between males, giving the opportunity for females to … non-preferred males.

A

competitive ability, reject

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26
Q

… of a partner isn’t proof of choice, but … in favour of another is.

A

acceptance, rejection

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27
Q

Andersson (1982) wanted to determine whether female widowbirds prefer males with … …. The males display to females and then she mates with one. He found that males with … … tended to mate with more females - but was this because they were better competitors or because females preferred them? He set up four groups of test males: one group had their tails …, another had their tails … …, and the other two were controls, one of which was left alone and the other had their tails cut and restuck (so were undergoing the same experimental procedure but didn’t have different tail lengths).

A

long tails, longer tails, elongated, cut short

28
Q

Andersson found that female widowbirds had a strong preference for…

A

males with lengthened tails, compared to the controls

  • in widowbirds there is a clear female choice for long tails - one of first studies to show female choice to be true
29
Q

Both m-m competition and f choice can be at work in the same system.

A

ah nice aha

30
Q

Low investment in offspring –> … sex
High investment in offspring –> … sex
Equal investment in offspring –> … sexes … and …

A

competing, choosy, both, compete, choose

31
Q

In crested auklets, both sexes invest heavily in the offspring. Both sexes have crests (only during the breeding season), though there are very slight differences in bill shape and size. We’d predict … sexual selection. Both males and females performed more … … to …-… models than …-… models. Both sexes prefer partners with … … - so mutual mate … is occurring. Additionally, in both sexes, more … interactions are won by long-crested birds. So both sexes … and both sexes …. Mutual … … occurs in this species.

A

mutual (both compete and both choose), courtship displays, long-crested, short-crested, long crests, choice, competitive, choose, compete, sexual selection

32
Q

In some species males invest more in reproduction than females. We would predict that the roles of the sexes would be …, so … will compete and … will be choosy.

A

reversed, females, males

33
Q

Male pipefish and seahorses get pregnant - the female provides the male with a clutch of eggs that he fertilises and carries around in a … …, providing oxygen and nutrients to support the offspring. He then gives birth to the offspring. During male pregnancy, females can produce eggs to fill … male pouches. Given an even … …, male pouch space is …. So females compete for males and males choose … females that produce … … than … ones. The … … … (OSR) is female-biased.

A

brood pouch, two, sex ratio, limited, large, more eggs, small, operational sex ratio

34
Q

In many insects, e.g. many crickets, the male transfers nutrients with his sperm during copulation in the form of … …. Because providing these is …, male crickets tend to be … as they do not want to give away their large reproductive investment to a female who will waste it. Males should be more choosy (and females should compete more) when the resources required to make the nuptial gift are …. This is true in the Australian katydid, whose food supply varies through the breeding season. When good quality food is …, males can easily produce nuptial gifts and are not choosy with who they mate with (and the males actually do the competing). Here, the environment is having an impact on sexual selection and the behaviours of males and females.

A

nuptial gifts, costly, choosy, scarce, abundant

35
Q

Male Mormon crickets transfer a huge (… of body mass) edible spermatophore to females when they mate, so can only mate …. Females can produce several clutches of eggs, providing they can persuade several males to mate. Females put relatively … resources into reproduction than males, hence the operational sex ratio is …-…. Females … with each other for males, and mating … (high density groups) occur where females compete for males and males are choosy. Females that are accepted for mating by males tend to be … and more …

A

25%, once, fewer, female-biased, compete, aggregations, larger, fecund

36
Q

Important: the … can influence the pattern of sexual selection.

A

environment

37
Q

Originally (ancestral state) all individuals had … of equal size and therefore could all mate with each other. At some point in time a mutant with … gametes arises. Will it do better (be selected for)?

If you assume that small gametes are … the size and that a mutant can make … as many as a result, then the answer is:

  • Yes - if the survival of the smaller embryo is … of the normal embryo
  • No if the survival of the smaller embryo is … of the normal embryo

When the new mutant with small gametes is rare, small gametes will only fuse with large gametes (as they are what’s around). The resulting zygote will be … the size of a normal zygote.

A

Gametes, small, half, twice, >50%, <50%, 75%

  • watch graph part of lecture 7 at 7:55
38
Q

From an initial situation of equal sized gametes it is possible for smaller gametes to be at an advantage, if the survival … is favourable - possible for two sexes to evolve in a sexually reproducing population in which there was initially only one sex. However, the advantage of the smaller gametes will decrease as they become … … (if fusion is random) - the chances of two small gametes will … if there are more in the population and two small gametes will produce a half size embryo with relatively low …. What is the solution?

A

curve, more common, increase, survival

The evolution of small gametes that are able to avoid fusing with each other (sperm can’t fuse with sperm).

39
Q

The above model is useful but somewhat unrealistic. It assumes that the small gametes were half the size of the large gametes. Although not impossible, this is very unlikely. More realistically, we might ask whether gametes that are slightly smaller would be at an advantage, which they almost certainly would be using the same model. Hence the evolution of the two sex system of reproduction.

A

Just a bit of explanation for you

40
Q

Males compete not just for matings, but for actual …

A

fertilisations (by engaging in sperm competition)

41
Q

Sperm competition is the competition between the sperm of two or more males inside…

A

the female’s reproductive tract

  • to maximise chance of fathering offspring
42
Q

Male damselflies…

A

remove the sperm of rivals from a female’s reproductive tract using specialised elaborate penises, before he inseminates her himself

43
Q

In insects, males from … species produce a higher proportion of … sperm than those from … species

A

polyandrous, viable, monogamous

  • due to selection pressures arising due to sperm competition
44
Q

Monogamous males often still engage in sperm competition by seeking …-… copulations, e.g. this behaviour is displayed in penguins.

A

extra-pair (outside of mating pair)

45
Q

Paired males actively … sperm competition, while simultaneously having to ensure their mate does not engage in extra-pair copulations with other males (as that could decrease their own …). Male may … their mates and drive off … (e.g. magpies do this).

A

promot, fitness, guard, rivals

46
Q

Seychelles warblers are small warblers that only occur in Seychelles. Male warblers mate guard during the days prior to their female partners laying their single egg. When the egg is laid the male need no longer guard the female as the egg has already been fertilised. The female is fertile … days prior to egg-laying. A copulation during this period could result in fertilisation of this egg (which occurs the day before the egg is laid). In the days before this period, many males intrude the territory and there are a few EPC attempts. As soon as the fertile period starts the paired male starts to guard his mate, effectively reducing the number of intrusions and EPC attempts, although…

Without male guarding behaviour, there were…

A

4, some EPCs are successful (probably due to female going out of her way to get extra matings)

far more intrusions, EPC attempts and successful attempts too - shows mate guarding is effective

47
Q

Does time spent guarding a mate against other males give a male more offspring than abandoning her and looking for more mates? Following copulation the male blue milkweed beetle remains … on the female’s back for some time so that other males cannot copulate with her.

A

mounted

48
Q

Dickinson removed male beetles from females and watched to see what would happen. … of separated males found a new mate within … minutes - so guarding results in missed mating opportunities. … of females found a new mate after male removal - so guarding has a substantial benefit to the male by preventing females from ….

A

25%, 30, 50%, remating

49
Q

In these beetles, If the … male to copulate with a female fertilises … of the eggs, males gain fitness by guarding the female rather than by searching for more females.

A

last (late sperm-precedence), >40%

50
Q

Other species copulate … to outcompete other males’ sperm. E.g. Male … copulate over 50 times with their partners (increases chance of optimal timing of insemination relative to fertilisation)

A

frequently, fulmars

51
Q

There are also strong evolutionary pressures on females to retain control over fertilisation and choose which males will father their offspring. They do this through … … …

A

cryptic female choice

52
Q

Cryptic female choice is female manipulation of … inside her … … so that a … male fertilises her eggs

A

sperm, reproductive tract, preferred

53
Q

Female chickens cannot always dictate which males mate with them, as males are much … and more …, so can … copulations. However, the females retain some control over which of the males that mate with her will father her offspring as they are able to … sperm from their cloacas after a male has inseminated them (a form of cryptic female choice). They are able to … the sperm of … males and accept that of ….

A

bigger, powerful, force, eject, eject, subordinate, dominant (to increase chance that female’s offspring will be fathered by a high-quality, dominant male)

54
Q

In Dunnocks, before a male copulates with a female, he often pecks her cloaca and she ejects a droplet of semen containing sperm. This looks like she is ejecting the sperm of a previous male so that the new male can fertilise her eggs. However, when you examine the semen droplet you find that the majority of the sperm are broken, tangled and …-…. It is more likely that she is…

A

non-viable, clearing out her reproductive tract of faulty sperm to make way for the new male’s ejaculate (the first male’s good quality sperm is already in her sperm storage tubules) - highlights need for care when interpreting behavioural observations

55
Q

Female hanging flies will only allow a male to transfer a full load of sperm if he provides her with a large … … in the form of a … …, which she eats during sperm transfer. This takes … minutes to complete, meaning only males that provide a nuptial gift that is at least … in size will end up occupying the female long enough for full transfer of sperm to occur (the female … copulation as soon as she has finished feeding).

A

nuptial gift, dead insect, 20, 20mm2, terminates

56
Q

Why do females engage in cryptic female choice?
They may gain:
1. Higher … … (by choosing higher … …) - nursery web spiders?
2. … offspring (by cryptic choice of genetically … males) - Gouldian finches?

A

quality offspring, quality fathers, more, compatible

57
Q

Male nursery web spiders give females nuptial gifts in the form of insects wrapped in white silk. Females copulate with males for longer if the nuptial gift is …. Females copulating with males that have given them a gift … more … and their … are more likely to …. Females manipulate paternity to gain a high quality father for their offspring (gift-giving ability being a measure of male quality).

A

large, store, sperm, eggs, hatch, eggs

58
Q

How do males that are unsuccessful in competition and are not chosen by females achieve reproductive success? In some species, … mating tactics are used, which can be equally … alternatives, or not equally … (i.e. the best of a bad job)

e.g. male elephant seals that are not beachmasters sneak copulations with females in the sea

A

alternative, rewarding, rewarding

59
Q

The male elephant seals that display this behaviour can’t gain the same large numbers of offspring that the beachmasters do but it is better than nothing.

A

I suppose it is really.

60
Q

Male … can adopt several mating tactics, depending on what other males in the population are doing. Initially, males adopt different tactics depending on their …

A

scorpionflies, size

61
Q

Large male scorpionflies guard … … that are attractive to females. Medium-sized males produce … … gifts to attract females. Small males … copulations on females (not a particularly successful tactic).

A

dead insects, salivary nuptial, force

  • large males more successful and gain more matings than smaller males
62
Q

Large males on average get … matings each, mediums … matings each and smalls … mating each

A

6, 2, 1

63
Q

If the large males are moved then the … males … the large males …. This shows that, faced with … from larger males, the smaller males adopt tactics that reflect their poor competitive ability.

A

medium, adopt, tactics, competition

64
Q

Paracerceis sculpta is an … that lives inside sponges and has … distinct male morphs with different advantages in terms of mating. The … males are the most dominant and can physically fight off other male morphs to mate with females. If an … male meets a … male, he simply picks him up and throws him out of the sponge. So … males have to be very careful to keep themselves hidden until a female comes close, at which point they jump out and sneak a copulation. If an … male meets a … male, the … male pretends to be a female, and the … wastes time courting with him. The … keeps this up in order to get close to females, and mates when he gets close to them.

A

isopod, three, alpha, alpha, gamma, alpha, beta, beta, alpha, beta

65
Q

If the 3 morphs represent distinct strategies that the males are bound to, the differences between them will be … determined, and they will all have equal … …. Shuster and Wade (1991) showed that the 3 morphs have distinct …. They measured the … … of each morph and found that they depended on how many males and females lived together. If an alpha and beta live together with one female, the … fathered most of the offspring. If an alpha and beta lived together with several females, however, the alpha could not monopolise them all and the beta ended up fathering more. In other combinations, even the gamma male did best. The calculation of average reproductive success for each morph in each combination of males and females multiplied by the natural occurrence of combinations in the wild showed that…

A

genetically, reproductive success, genotypes (determined by 3 different alleles), reproductive success, alpha, the 3 genetically different male morphs had equal fitness (this species employs alternative mating strategies, each of which has equal fitness)

66
Q

Blue-gilled sunfish males have 3 mating strategies (… large males, little …, medium …). Territorial males are large and guard nests that attract females that are ready to spawn. Little sneakers sneak in and release their sperm at the same time as the …-… male to attempt to fertilise some of the female’s eggs. Satellies have the body colouration of … and slip between the territorial male and his mate when the female is spawning. The 3 are morphologically different and all get reasonable numbers of matings.

A

territorial, sneakers, satellites, territory-holding, females

67
Q

Molecular studies have shown that … males father most of the offspring (…%) - due to sperm competition.

A

territorial, 98.7

APS209 Behavioural Ecology (5 decks)

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