Lek mating

A lek is an aggregation of male animals gathered to engage in competitive displays and courtship rituals, known as lekking, to entice visiting females which are surveying prospective partners with which to mate.

Llewelyn Lloyd's The Game birds and wild fowl of Sweden and Norway (1867) introduces it (capitalised and in single quotes, as 'Lek') explicitly as a Swedish term.

[6] Lekking was originally described in the Tetraonidae (grouse, boldface in cladogram), in particular the black grouse (Swedish: "orrlek") and capercaillie (Swedish: "tjäderlek"), but it is widely distributed phylogenetically among other birds, and in many other animal groups within the vertebrates and the arthropods, as shown in the cladogram.

Atlantic cod[9] Desert pupfish[10] Cichlids[11] Amphibians: some frogs[12][13] Reptilia: Marine iguanas[14] Tetraonidae[1] (grouse) Otididae[7] (bustards) Scolopacidae[7] (sandpipers) Psittacidae[7] (parrots) Cotingidae[7] (cotingas) Pipridae[7] (manakins) Pycnonotidae[7] (bulbuls) Ploceidae[7] (weavers) Paradisaeidae[7] (birds of paradise) Bats[15][16] Bovidae: several species[17][18][19][20] Pinnipeds[21][22] Decapoda: fiddler crab[23] Vespidae: paper wasps[24] Pompilidae: tarantula hawk wasps[25] Formicidae: some ants[26] Apoidea: some bees[27] Lepidoptera: some butterflies[28] and moths[29][30] Diptera: fruit flies,[31] druid flies[32] There are two types of lekking arrangement: classical and exploded.

[36] A well-known example of exploded leks is the "booming" call of the kākāpō, the males of which position themselves many kilometres apart from one another to signal to potential mates.

In some species of manakin, subordinate betas may inherit an alpha's display site, increasing the chances of female visitation.

[1] A positive correlation was also found between attendance, magnitude of exaggerated traits, age, frequency of fights, and mating success.

[45] However, lekking reduces the cost of female searching because the congregating of males makes mate selection easier.

Stronger selection should lead to impaired survival, as it decreases genetic variance and ensures that more offspring have similar traits.

[51] This implies that a female gains indirect benefits from her choice in the form of "good genes" for her offspring.

[53][54] Zahavi's handicap principle may offer a resolution to the lek paradox, for if females select for the condition of male ornaments, then their offspring have better fitness.

Another potential resolution to the lek paradox is Rowe and Houle's theory that sexually selected traits depend on physical condition, which might in turn, summarize many genetic loci.

[52] This is the genic capture hypothesis, which describes how a significant amount of the genome is involved in shaping the traits that are sexually selected.

[52] In addition, W. D. Hamilton and Marlene Zuk proposed that sexually selected traits might signal resistance to parasites.

[49] Several possible mechanisms have been proposed as to why males cluster into leks, including the hotshot, hotspot, black hole, kin selection, and predation protection hypotheses, as described below.

[3] The hotspot model also predicts that lek size is dependent upon the number of females inhabiting a patch of land.

[57] This prediction is difficult to test, but there was a negative correlation found between male aggressiveness and female visitation in the little bustard population, suggesting that the model might be correct.

Kin selection explains that related males congregate to form leks, as a way to attract females and increase inclusive fitness.

Greater sage-grouse at a lek, with multiple males displaying for the less conspicuous females
Sage grouse lek mating arena, in which each male, alpha-male (highest ranking), beta-male, gamma-male, etc., guards a territory of a few meters in size. The dominant males may each attract eight or more females. [ 33 ] Higher-ranking individuals have larger personal space bubbles. [ 34 ] Bird leks may have 10-200 individuals. A strict hierarchy accords the top-ranking males the most prestigious central territories. Females come to choose mates when the males' hierarchy is established, and preferentially mate with the dominants in the centre.
Lekking behaviour in the Clusiid fly Paraclusia tigrina
A group of three male great-tailed grackles trying to attract the attention of a receptive female
In the little bustard , the presence of a hotshot male seems to attract males and females to the lek.
In manakins , males aggregate near hotspots with plentiful fruit, where females tend to go.
In black grouse , leks are composed of brothers and half-brothers, suggesting a kin selection mechanism.