Analyzing Male Reproductive Strategies in Bird Populations
School
University of Guelph**We aren't endorsed by this school
Course
ZOO 4070
Subject
Anthropology
Date
Dec 11, 2024
Pages
6
Uploaded by SuperBuffalo3791
Question 1 deals with the following scenario: Imagine a species with 2 kinds of males: fighters and female mimics. Of the total number of males in the population, 25% are successful fighters that mate exclusively with 3 females on average. 50% of the males in the population are unsuccessful fighters that do not mate with any females because they are either chased away by the better fighters or have their paternity stolen by female mimics. The final quarter of the male population practices female mimicry and these males gain on average one female mating. (1A) If you were to calculate the fitness of successful fighters while excluding the unsuccessful fighters, what would you conclude about the proximate control of the two tactics? [1 mark](1B) If you were to calculate the mean fitness of the two types while including data from the unsuccessful fighters, would you reach the same conclusion? Why or why not? [2 marks](1C) Given the conclusion for question (9B), what would happen in a population in which female mimics made up 50% of the population, if the pool of real females available to these males was the same as that available for a population in which only 25% of the males were female mimics? [2 marks]
Questions 2-4 deal with the following scenario: Hooded warblers are small migratory birds that breed in northeastern forests. Males and females form socially monogamous pair bonds during the breeding season. Mean brood size is 4 and each pair rears 2 broods in a season. In large tracts of continuous forest both males and females regularly leave their territory to seek extra-pair copulations (EPCs), resulting in 50% of the nestlings being fathered from outside the pair bond. In isolated forest patches, males regularly leave their territories and cross gaps in the forest to seek EPCs, while females rarely do so. As a result, males gain extra-pair paternity and are able to preserve 100% of their paternity in their own nest. (2) Which type of habitat (continuous or fragmented) might you expect offspring from the first brood to want the mother to provide parental care for a longer period to time and why [show calculations]? [3 marks](3) Although males in isolated fragments preserve their own paternity and are able to seek out EPCs, only 30% of the males in isolated fragments actually acquire a mate. Provide 3 tests (and their accompanying predictions) that you would do to show that males in these two habitats follow an ideal-despotic rather than an ideal-free distribution. [4 marks]
(4A) In continuous forest,either sex may choose to defend territories. Construct a game theory payoff matrix based on the following parameters: The probability of eggs surviving (P) increases with the number of parents (0-2) defending, such that: P0< P1< P2.A female lays weggs if she defends but is able to lay Weggs if she doesn’t defend (where W> w) because she expends less energy. If a male doesn’t defend, he has more time to fool around so he gains Nextra-pair offspring that survive but also loses half of his paternity in his own nest whereas if he defended he would have full paternity. [4 marks] (4B) If w= 4, W= 6, P0= 0.1, and P1 = 0.5, P2 = 1.0, what does Nhave to be less thanin order to make this a case of By-product mutualism? Show calculations. [2 marks]
(5)Which socially monogamous species would you expect the offspring to want the mother to provide parental care for a longer period to time: Species A in which a mother’s nextbrood will be 4 offspring but has a 50% chance of having extra-pair young OR species B in which a mother’s nextbrood will only be 2 offspring but never copulates outside the pair bond? (circle only one) [1 mark]A) species A B) species B C) same length of time D) do not have enough data to tell (6)If we hypothesize that the behavioral differences among bluegill males are the product of a conditional strategy, then which of the following predictions would follow from this hypothesis? (circle only one) [1 mark]A) Territorial males should have territorial sons. B) The reproductive success of the three types could be different. C) The environment should have no effect on the development of satellite behavior. D) The presence of satellites should increase the fitness of those females whose eggs they fertilize. (7)Given that eggs can be fertilized either “instantaneously” or “continuously”, you might expect different male adaptations in each of these situations. For each scenario, provide one adaptation related to traits of spermand one adaptation related to male behaviour[4 marks]Instantaneous model: Sperm trait: _______________________________________________________ Male behaviour: ____________________________________________________ Continuous model: Sperm trait: ______________________________________________________ Male behaviour: ____________________________________________________
(8)Golden-winged sunbirds can defend territories with varying levels of nectar (uL) per flower. The higher the quality the territory, the less time it takes to obtain the minimum daily energy requirements, show in the table below: territory type nectar (uL)/flower time to get energy (h) A 1 5.5 B 2 3.8 C 3 2.7 D 4 2.2 E 5 1.9 F 6 1.8 However, the higher quality of the territory, the more time an individual has to spend defending it; this relationship can be approximated by the equation: y = 0.01x + 0.22 hr; where x = nectar/flower. It has also been estimated from field data that it takes about 1000 calories/hr for foraging, 400 cal/hr for resting and 3000 cal/hr for territorial defence. If given the chance to upgrade, it worthwhile for an individual who is defending territory type C to move to territory D? What about an individual from B to go to C? Show your calculations. [6 marks]
(9) Imagine that a new species of pheasant has been discovered. Males of this species have long black feathers protruding from their foreheads and they compete for access to females. Females are known to mate with males that have the longest forehead feathers. Males of a closely related ancestral pheasant species that live in the same area do not have forehead feathers. (9A) What factor is most likely responsible for the evolution of male competition for females in this species? Explain how this factor could lead to sex role reversal. [2 marks] (9B) Researchers want to find out whether there is support for the sensory exploitation model of mate choice in this species. Describe a study that the researchers could conduct which would help them determine if there is support for this model. [2 marks] (9C) Describe a study that the researchers could conduct which would help them determine if there is support for the good genesmodel of mate choice. [2 marks]