Finding Sex Partners in Animal Kingdom


Advertisements
Advertisements

Related Posts:


Photo (a) shows a yellow sea horse; (b) shows a pipefish, which is green and tubular with a long snout.
Polyandrous mating, in which one female mates with many males, occurs in the (a) seahorse and the (b) pipefish. (credit a: modification of work by Brian Gratwicke; credit b: modification of work by Stephen Childs)

OpenStax Biology 2e

Not all animals reproduce sexually, but many that do have the same challenge: they need to find a suitable mate and often have to compete with other individuals to obtain one. Significant energy is spent in the process of locating, attracting, and mating with the sex partner. Two types of selection occur during this process: intersexual selection, where individuals of one sex choose mates of the other sex, and intrasexual selection, the competition for mates between species members of the same sex. Intersexual selection is often complex because choosing a mate may be based on a variety of visual, aural, tactile, and chemical cues. An example of intersexual selection is when female peacocks choose to mate with the male with the brightest plumage. This type of selection often leads to traits in the chosen sex that do not enhance survival, but are those traits most attractive to the opposite sex (often at the expense of survival). Intrasexual selection involves mating displays and aggressive mating rituals such as rams butting heads—the winner of these battles is the one that is able to mate. Many of these rituals use up considerable energy but result in the selection of the healthiest, strongest, and/or most dominant individuals for mating.

Three general mating systems, all involving innate as opposed to learned behaviors, are seen in animal populations: monogamous, polygynous, and polyandrous.

In monogamous systems, one male and one female are paired for at least one breeding season. In some animals, such as the gray wolf, these associations can last much longer, even a lifetime. Several theories may explain this type of mating system. The “mate-guarding hypothesis” states that males stay with the female to prevent other males from mating with her. This behavior is advantageous in such situations where mates are scarce and difficult to find. Another explanation is the “male-assistance hypothesis,” where males that help guard and rear their young will have more and healthier offspring. Monogamy is observed in many bird populations where, in addition to the parental care from the female, the male is also a major provider of parental care for the chicks. A third explanation for the evolutionary advantages of monogamy is the “female-enforcement hypothesis.” In this scenario, the female ensures that the male does not have other offspring that might compete with her own, so she actively interferes with the male’s signaling to attract other mates.

Polygynous mating refers to one male mating with multiple females. In these situations, the female must be responsible for most of the parental care as the single male is not capable of providing care to that many offspring. In resourced-based polygyny, males compete for territories with the best resources, and then mate with females that enter the territory, drawn to its resource richness. The female benefits by mating with a dominant, genetically fit male; however, it is at the cost of having no male help in caring for the offspring. An example is seen in the yellow-rumped honeyguide, a bird whose males defend beehives because the females feed on their wax. As the females approach, the male defending the nest will mate with them. Harem mating structures are a type of polygynous system where certain males dominate mating while controlling a territory with resources. Harem mating occurs in elephant seals, where the alpha male dominates the mating within the group. A third type of polygyny is a lek system. Here there is a communal courting area where several males perform elaborate displays for females, and the females choose their mate from this group. This behavior is observed in several bird species including the sage grouse and the prairie chicken.

In polyandrous mating systems, one female mates with many males. These types of systems are much rarer than monogamous and polygynous mating systems. In pipefishes and seahorses, males receive the eggs from the female, fertilize them, protect them within a pouch, and give birth to the offspring. Therefore, the female is able to provide eggs to several males without the burden of carrying the fertilized eggs.

Source:

Clark, M., Douglas, M., Choi, J. Biology 2e. Houston, Texas: OpenStax. Access for free at: https://openstax.org/details/books/biology-2e

Advertisements
Advertisements

Research Article: Structured mating: Patterns and implications

Date Published: April 6, 2017 Publisher: Public Library of Science Author(s): Ronnie Sebro, Gina M. Peloso, Josée Dupuis, Neil J. Risch, Xiaofeng Zhu Abstract: Genetic similarity of spouses can reflect factors influencing mate choice, such as physical/behavioral characteristics, and patterns of social endogamy. Spouse correlations for both genetic ancestry and measured traits may impact genotype … Continue reading

Research Article: Searching for the genes driving assortative mating

Date Published: February 7, 2019 Publisher: Public Library of Science Author(s): Erica L. Westerman Abstract: Animals display an astonishing array of diverse colors and patterns, and animals also exhibit preferences for these diverse, species-specific traits when choosing a mate (i.e., assortative mate preference). It is hypothesized that in order for both preference and trait to … Continue reading

Research Article: Scrutinizing assortative mating in birds

Date Published: February 21, 2019 Publisher: Public Library of Science Author(s): Daiping Wang, Wolfgang Forstmeier, Mihai Valcu, Niels J. Dingemanse, Martin Bulla, Christiaan Both, Renée A. Duckworth, Lynna Marie Kiere, Patrik Karell, Tomáš Albrecht, Bart Kempenaers, Michael D. Jennions Abstract: It is often claimed that pair bonds preferentially form between individuals that resemble one another. … Continue reading

Research Article: Genetic dissection of assortative mating behavior

Date Published: February 7, 2019 Publisher: Public Library of Science Author(s): Richard M. Merrill, Pasi Rastas, Simon H. Martin, Maria C. Melo, Sarah Barker, John Davey, W. Owen McMillan, Chris D. Jiggins, Mark Siegal Abstract: The evolution of new species is made easier when traits under divergent ecological selection are also mating cues. Such ecological … Continue reading

Research Article: Diploids in the Cryptococcus neoformans Serotype A Population Homozygous for the α Mating Type Originate via Unisexual Mating

Date Published: January 30, 2009 Publisher: Public Library of Science Author(s): Xiaorong Lin, Sweta Patel, Anastasia P. Litvintseva, Anna Floyd, Thomas G. Mitchell, Joseph Heitman, Alex Andrianopoulos. http://doi.org/10.1371/journal.ppat.1000283 Abstract: The ubiquitous environmental human pathogen Cryptococcus neoformans is traditionally considered a haploid fungus with a bipolar mating system. In nature, the α mating type is overwhelmingly … Continue reading

Research Article: Mating patterns and post-mating isolation in three cryptic species of the Engystomops petersi species complex

Date Published: April 7, 2017 Publisher: Public Library of Science Author(s): Paula A. Trillo, Andrea E. Narvaez, Santiago R. Ron, Kim L. Hoke, William J. Etges. http://doi.org/10.1371/journal.pone.0174743 Abstract: Determining the extent of reproductive isolation in cryptic species with dynamic geographic ranges can yield important insights into the processes that generate and maintain genetic divergence in … Continue reading

Research Article: Condition-Dependent Effects of Mating on Longevity and Fecundity of Female Medflies: The Interplay between Nutrition and Age of Mating

Date Published: July 24, 2013 Publisher: Public Library of Science Author(s): Stella A. Papanastasiou, Christos T. Nakas, James R. Carey, Nikos T. Papadopoulos, John Vontas. http://doi.org/10.1371/journal.pone.0070181 Abstract: In various species mating exerts direct and indirect effects on female demographic traits ranging from life span shortening to behavioural shifts. A wealth of data regarding effects of … Continue reading

Research Article: Female Fitness Optimum at Intermediate Mating Rates under Traumatic Mating

Date Published: August 22, 2012 Publisher: Public Library of Science Author(s): Rolanda Lange, Tobias Gerlach, Joscha Beninde, Johanna Werminghausen, Verena Reichel, Nils Anthes, Anna Dornhaus. http://doi.org/10.1371/journal.pone.0043234 Abstract: Traumatic mating behaviors often bear signatures of sexual conflict and are then typically considered a male strategy to circumvent female choice mechanisms. In an extravagant mating ritual, the hermaphroditic … Continue reading

Research Article: Mating First, Mating More: Biological Market Fluctuation in a Wild Prosimian

Date Published: March 5, 2009 Publisher: Public Library of Science Author(s): Ivan Norscia, Daniela Antonacci, Elisabetta Palagi, Sarah Frances Brosnan. http://doi.org/10.1371/journal.pone.0004679 Abstract: In biology, economics, and politics, distributive power is the key for understanding asymmetrical relationships and it can be obtained by force (dominance) or trading (leverage). Whenever males cannot use force, they largely depend on … Continue reading

Research Article: Inversion of the Chromosomal Region between Two Mating Type Loci Switches the Mating Type in Hansenula polymorpha

Date Published: November 20, 2014 Publisher: Public Library of Science Author(s): Hiromi Maekawa, Yoshinobu Kaneko, Joseph Heitman Abstract: Yeast mating type is determined by the genotype at the mating type locus (MAT). In homothallic (self-fertile) Saccharomycotina such as Saccharomyces cerevisiae and Kluveromyces lactis, high-efficiency switching between a and α mating types enables mating. Two silent … Continue reading

Advertisements
Advertisements