Editing Behavioral ecology (section)

==Sexual selection==

===Mate choice by resources===
In many sexually reproducing species, such as [[mammal]]s, [[bird]]s, and [[amphibian]]s, females are able to bear offspring for a certain time period, during which the males are free to mate with other available females, and therefore can father many more offspring to pass on their genes. The fundamental difference between male and female reproduction mechanisms determines the different strategies each sex employs to maximize their [[reproductive success]]. For males, their reproductive success is limited by access to females, while females are limited by their access to resources. In this sense, females can be much choosier than males because they have to bet on the resources provided by the males to ensure reproductive success.<ref name=Davies/>

Resources usually include nest sites, food and protection. In some cases, the males provide all of them (e.g. [[sedge warbler]]s).<ref>{{cite journal|last=Buchanan |first=K.L.|author2=Catchpole, C.K. |title=Song as an indicator of male parental effort in the sedge warbler|journal=Proceedings of the Royal Society |year=2000 |volume=267 |pages=321–326 |doi=10.1098/rspb.2000.1003|pmid=10722211|issue=1441|pmc=1690544}}</ref>  The females dwell in their chosen males' territories for access to these resources. The males gain ownership to the territories through [[male–male competition]] that often involves physical aggression. Only the largest and strongest males manage to defend the best quality nest sites. Females choose males by inspecting the quality of different territories or by looking at some male traits that can indicate the quality of resources.<ref name=Davies/> One example of this is with the grayling butterfly (''[[Grayling (butterfly)|Hipparchia semele]]''), where males engage in complex flight patterns to decide who defends a particular territory. The female grayling butterfly chooses a male based on the most optimal location for [[oviparity|oviposition]].<ref>{{cite iucn |author=van Swaay, C. |author2=Wynhoff, I. |author3=Verovnik, R. |author4=Wiemers, M. |author5=López Munguira, M. |author6=Maes, D. |author7=Sasic, M. |author8=Verstrael, T. |author9=Warren, M. |author10=Settele, J. |date=2010 |title=''Hipparchia semele'' |volume=2010 |page=e.T173254A6980554 |doi=10.2305/IUCN.UK.2010-1.RLTS.T173254A6980554.en |access-date=13 November 2021}}</ref> Sometimes, males leave after mating. The only resource that a male provides is a [[nuptial gift (animal behavior)|nuptial gift]], such as protection or food, as seen in ''[[Drosophila subobscura]].''<ref>{{cite journal|last=Dussourd|first=D.E.|author2=Harvis, C.A. |author3=Meinwald, J. |author4= Eisner, T. |title=Pheromonal advertisement of a nuptial gift by a male moth |journal=Proceedings of the National Academy of Sciences of the United States of America |year=1991 |volume=88 |pages=9224–9227 |doi=10.1073/pnas.88.20.9224|issue=20|bibcode = 1991PNAS...88.9224D |pmid=1924385 |pmc=52686|doi-access=free}}</ref><ref>{{cite journal | last1 = Steele | first1 = RH | year = 1986 | title = Courtship feeding in ''Drosophila subobscura''. 2. Courtship feeding by males influences female mate choice | journal = Animal Behaviour | volume = 34 | pages = 1099–1108 | doi = 10.1016/s0003-3472(86)80169-5 | s2cid = 53156432 }}</ref>  The female can evaluate the quality of the protection or food provided by the male so as to decide whether to mate or not or how long she is willing to copulate.

===Mate choice by genes===
When males' only contribution to offspring is their sperm, females are particularly choosy.  With this high level of female choice, sexual ornaments are seen in males, where the ornaments reflect the male's social status. Two hypotheses have been proposed to conceptualize the genetic benefits from female [[mate choice]].<ref name="Davies">{{cite book |author=Nicholas B. Davies |author2=John R. Krebs |author3=Stuart A. West |title=An Introduction to Behavioral Ecology|year=2012|publisher=Wiley-Blackwell|location=West Sussex, UK|isbn=978-1-4051-1416-5|pages=193–202}}</ref>

First, the good genes hypothesis suggests that female choice is for higher genetic quality and that this preference is favored because it increases fitness of the offspring.<ref name=ryan>{{cite journal|last=Ryan|first=Michael J.|author2=Anne Keddy-Hector|title=Directional patterns of female mate choice and the role of sensory biases |journal=The American Naturalist|date=March 1992|volume=139|pages=S4–S35|jstor=2462426|doi=10.1086/285303|s2cid=86383459}}</ref>  This includes [[Handicap principle|Zahavi's handicap hypothesis]] and [[Evolutionary arms race|Hamilton and Zuk's host and parasite arms race]]. Zahavi's handicap hypothesis was proposed within the context of looking at elaborate male sexual displays. He suggested that females favor ornamented traits because they are handicaps and are indicators of the male's genetic quality. Since these ornamented traits are hazards, the male's survival must be indicative of his high genetic quality in other areas. In this way, the degree that a male expresses his sexual display indicates to the female his genetic quality.<ref name="Davies" />  Zuk and Hamilton proposed a hypothesis after observing disease as a powerful selective pressure on a rabbit population. They suggested that sexual displays were indicators of resistance of disease on a genetic level.<ref name="Davies" />

Such 'choosiness' from the female individuals can be seen in wasp species too, especially among ''[[Polistes dominula]]'' wasps. The females tend to prefer males with smaller, more elliptically shaped spots than those with larger and more irregularly shaped spots. Those males would have reproductive superiority over males with irregular spots.

In [[Marbled newt|marbled newts]], females show preference to mates with larger crests. This however, is not considered a handicap as it does not negatively affect males' chances of survival. It is simply a trait females show preference for when choosing their mate as it is an indication of health and fitness.<ref>{{Cite journal |last1=Zuiderwijk |first1=Annie |last2=Sparreboom |first2=Max |date=1986-01-01 |title=Territorial Behaviour in Crested Newt Triturus Cristatus and Marbled Newt T. Marmoratus (Amphibia, Urodela) |url=https://brill.com/view/journals/btd/56/2/article-p205_2.xml |journal=Bijdragen tot de Dierkunde |language=en |volume=56 |issue=2 |pages=205–213 |doi=10.1163/26660644-05602002 |issn=0067-8546|doi-access=free }}</ref>

Fisher's hypothesis of runaway sexual selection suggests that female preference is genetically correlated with male traits and that the preference co-evolves with the evolution of that trait, thus the preference is under indirect selection.<ref name=ryan/> Fisher suggests that female preference began because the trait indicated the male's quality. The female preference spread, so that the females' offspring now benefited from the higher quality from specific trait but also greater attractiveness to mates. Eventually, the trait only represents attractiveness to mates, and no longer represents increased survival.<ref name="Davies" />

An example of mate choice by genes is seen in the cichlid fish ''[[Tropheus moorii]]'' where males provide no parental care. An experiment found that a female ''T. moorii'' is more likely to choose a mate with the same color morph as her own.<ref>{{cite journal | last1 = Salzburger | first1 = Walter | last2 = Niederstätter | first2 = Harald | last3 = Brandstätter | first3 = Anita | last4 = Berger | first4 = Burkhard | last5 = Parson | first5 = Walther | last6 = Snoeks | first6 = Jos | last7 = Sturmbauer | first7 = Christian | year = 2006 | title = Colour-assortative mating among populations of ''Tropheus moorii'', a cichlid fish from Lake Tanganyika, East Africa | journal = Proceedings of the Royal Society B: Biological Sciences | volume = 273 | issue = 1584| pages = 257–66 | doi=10.1098/rspb.2005.3321 | pmid=16543167 | pmc=1560039}}</ref> In another experiment, females have been shown to share preferences for the same males when given two to choose from, meaning some males get to reproduce more often than others.<ref name=":3">{{cite journal | last1 = Steinwender | first1 = Bernd | last2 = Koblmüller | first2 = Stephan | last3 = Sefc | first3 = Kristina M. | year = 2011| title = Concordant female mate preferences in the cichlid fish ''Tropheus moorii'' | journal = Hydrobiologia | volume =  682| issue = 1| pages =  121–130| doi=10.1007/s10750-011-0766-5| pmid = 24293682 | pmc = 3841713 }}</ref> 

===Sensory bias===
The sensory bias hypothesis states that the preference for a trait evolves in a non-mating context, and is then exploited by one sex to obtain more mating opportunities. The competitive sex evolves traits that exploit a pre-existing bias that the choosy sex already possesses. This mechanism is thought to explain remarkable trait differences in closely related species because it produces a divergence in signaling systems, which leads to reproductive isolation.<ref>{{cite journal|year=2002|title=How sensory drive can promote speciation |journal=Trends in Ecology and Evolution|volume=17|issue=12|pages=571–577|doi=10.1016/S0169-5347(02)02595-8 |last1=Boughman|first1=J. W.}}</ref>

Sensory bias has been demonstrated in [[Guppy|guppies]], [[Fresh water|freshwater]] fish from [[Trinidad and Tobago]]. In this mating system, female guppies prefer to mate with males with more orange body coloration. However, outside of a mating context, both sexes prefer animate orange objects, which suggests that preference originally evolved in another context, like foraging.<ref>{{cite journal|last2=Hughes|first2=K. A. |last3=Grether|first3=G. F.|last4=Baril|first4=C. T.|year=2002|title=A possible non-sexual origin of mate preference: are male guppies mimicking fruit?|journal=Proceedings of the Royal Society B |volume= 269|issue=1490|pages=475–481|doi=10.1098/rspb.2001.1891|last1=Rodd|first1=F. H.|pmid=11886639|pmc=1690917}}</ref> Orange fruits are a rare treat that fall into streams where the guppies live. The ability to find these fruits quickly is an adaptive quality that has evolved outside of a mating context. Sometime after the affinity for orange objects arose, male guppies exploited this preference by incorporating large orange spots to attract females.

Another example of sensory exploitation is in the water mite ''[[Neumania papillator]]'', an [[ambush predator]] that hunts [[copepods]] (small crustaceans) passing by in the water column.<ref name=":12">{{Cite journal |last=Proctor |first=Heather C.|date=1991-10-01|title=Courtship in the water mite ''Neumania papillator'': males capitalize on female adaptations for predation |journal=Animal Behaviour |volume=42 |issue=4 |pages=589–598 |doi=10.1016/S0003-3472(05)80242-8|s2cid=53166756}}</ref> When hunting, ''N. papillator'' adopts a characteristic stance termed the 'net stance' - their first four legs are held out into the water column, with their four hind legs resting on aquatic vegetation; this allows them to detect vibrational stimuli produced by swimming prey and use this  to orient towards and clutch at prey.<ref name=":02">{{Cite journal |last=Proctor |first=Heather C.|date=1992-10-01|title=Sensory exploitation and the evolution of male mating behaviour: a cladistic test using water mites (Acari: Parasitengona) |journal=Animal Behaviour |volume=44 |issue=4|pages=745–752|doi=10.1016/S0003-3472(05)80300-8|s2cid=54426553}}</ref> During courtship, males actively search for females<ref name=":2">{{Cite journal|last=Proctor|first=H. C.|date=1992-01-01|title=Effect of Food Deprivation on Mate Searching and Spermatophore Production in Male Water Mites (Acari: Unionicolidae) |journal=Functional Ecology|volume=6|issue=6|pages=661–665 |doi=10.2307/2389961|jstor=2389961}}</ref> - if a male finds a female, he slowly circles around the female whilst trembling his first and second leg near her.<ref name=":12" /><ref name=":02" /> Male leg trembling causes females (who were in the 'net stance') to orient towards often clutch the male.<ref name=":12" /> This did not damage the male or deter further courtship; the male then deposited [[spermatophore]]s and began to vigorously fan and jerk his fourth pair of legs over the spermatophore, generating a current of water that passed over the spermatophores and towards the female.<ref name=":12" /> Sperm packet uptake by the female would sometimes follow.<ref name=":12" /> Heather Proctor hypothesised that the vibrations trembling male legs made were done to mimic the vibrations that females detect from swimming prey - this would trigger the female prey-detection responses causing females to orient and then clutch at males, mediating courtship.<ref name=":12" /><ref name="animalbehaviour">{{cite book |title=Animal Behaviour: A Evolutionary Approach|last=Alcock|first=John|publisher=[[Sinauer]] |isbn=978-0-87893-966-4|edition=10th|pages=70–72|author-link=John Alcock (behavioral ecologist)|date=2013-07-01}}</ref> If this was true and males were exploiting female predation responses, then hungry females should be more receptive to male trembling – Proctor found that unfed captive females did orient and clutch at males significantly more than fed captive females did, consistent with the sensory exploitation hypothesis.<ref name=":12" />

Other examples for the sensory bias mechanism include traits in [[auk]]lets,<ref>{{cite journal |last2=Hunter |first2=F. M.|year=1998|title=Heterospecific mating preferences for a feather ornament in least auklets |journal=Behavioral Ecology|volume=9 |issue=2|pages=187–192 |doi=10.1093/beheco/9.2.187|last1=Jones|first1=I. L.}}</ref> [[wolf spider]]s,<ref>{{cite journal|last2=Uetz|first2=G. W.|year=1996|title=Female choice and pre-existing bias: Visual cues during courtship in two Schizocosawolff spiders|journal=Animal Behaviour |volume=52|pages=167–181 |doi=10.1006/anbe.1996.0162|last1=McClinktock|first1=W. J.|s2cid=24629559}}</ref> and [[manakin]]s.<ref>{{cite journal |year=1996|title=Phylogenetic tests of alternative intersexual selection mechanisms: Trait macroevolution in a polygynous clade|journal=The American Naturalist |volume=149 |issue=4 |pages=688–692 |doi=10.1086/286014|jstor=2463543|last1=Prum|first1=R. O.|s2cid=85039370}}</ref> Further experimental work is required to reach a fuller understanding of the prevalence and mechanisms of sensory bias.<ref>{{cite journal |last2=Houle|first2=D.|last3=Travis|first3=J.|year=2005|title=Sensory bias as an explanation for the evolution of mate preferences|journal=American Naturalist|volume=166|issue=4|pages=437–446 |doi=10.1086/444443 |pmid=16224700 |last1=Fuller|first1=R. C.|s2cid=4849390}}</ref>