Eco-Vocab: Lek

No, not this:

 

This:

Let me start from the beginning. In nature there are any number of mating strategies animals use to make sure they pass on their genes to the greatest number offspring, preferably offspring who can manage to survive to have a bunch of their own offspring (this is fitness). Males, who generally have a near unlimited supply of sperm and a very low energetic cost of reproduction (particularly in species where the male doesn’t help with the kids at all), tend to go for quantity. They want to impregnate the most females possible.

Females, on the other have a comparatively large investment of resources, energy, and time in producing offspring (even in species where the female doesn’t hang around after having the offspring). Pregnancy, egg laying, raising kids. It takes a lot. Females need to be choosier. They want quality. They put so much in to each individual offspring, so they want to be sure they are getting the best genes possible from the strongest, most successful male.

This leads to all kinds of scenarios where many of the females all want to mate with the “best” male, and each male wants to attract as many females as possible (in general – I know there are many exceptions). That’s why polygyny is super common in the animal kingdom (not to mention among humans). In some cases, as with lions and elephant seals, one dominant male will control breeding rights with all the females in the group. Or, as with bowerbirds, a male will create an extravagant display and females will come along one at a time and decide whether to mate with him or not. Sometimes males will fight for dominance in front of females to prove who is the best mate, as bighorn sheep do. (Oh yeah, they kick each other in the balls, too.)

Some males have figured out that sticking with a single mate for a season or a lifetime (with as much action on the side as they both can get, of course) is the best way for them to increase their fitness. There are nearly as many mating strategies in the animal kingdom as there are species of animal. But one of the strangest is the lek.

Primarily known among grouse species and their close relatives, lekking is relatively uncommon and mainly confined to birds – although some fish and insects do it. In a lek, basically, a large group of eligible and horny bachelors get together in the same place, fairly close to each other. They then each do some kind of individual (although, rarely it can be coordinated) mating display. They may show impressive feathers, or brightly colored throat sacs.

Male Greater Prairie Chicken (Tympanuchus cupido) inflating brightly colored neck sacs to attract mates.

They may call out, do an ornate dance, jump up and down, or even jostle or fight each other. Their main goal is to show that they are the biggest, strongest, most healthy males in the group. That they are free of parasites, capable of obtaining lots of food, or can beat up all the other males. (Okay, there are lots of the theories about male display and sexual selection – that’s a whole ‘nother post).

In any case, by whatever definition of sexiness this particular species uses, the females in the area all gather around and watch the males in an attempt to determine who they should mate with. Luckily, females don’t usually have to settle for an inferior male as the guys are magnanimous  with the ladies – there’s semen enough for all. Usually, the vast majority of the females choose the same male. They are all using pretty similar criteria to determine the most attractive male, and they all want George Clooney. A few, for whatever reason go for other males, not the top dog, but still very high quality – in this scenario Zachary Quinto and Colin Firth would each get a few matings too. And the vast majority of males in the lek get nothing.

YES, HE GETS ALL THE FEMALES. NO, NONE FOR YOU.

So then, why lek? How did it evolve and why do less fit males participate if they have little chance of getting any? Well, we can’t know for sure but since less fit males don’t have a great chance of mating in any scenario it’s likely that being part of a lek increases their probably of mating somehow, at the time or in future leks. It may have started because all the females were consistently gathering around a single, desirable male and those other males who displayed near him received a benefit from his reflected glory. More males displaying attracts more females, and so on.

Perhaps mating success increases with the number of times a male is part of a lek – they learn each other moves and improve their standing in future mating seasons. Or maybe since all the females are going for the top male at the same time, there’s at least a chance a low-ranked male can convince someone to pick him while George is busy. In any case, if all the females are watching the group of males, you sure don’t want to be somewhere else where there are zero females.

Understand the concept of lekking? Are you sure? Let’s use it in a sentence:

“Seeing the group of skater boys doing tricks in the park while the girls all watched them made me think of lekking Greater Sage Grouse (Centrocercus urophasianus) on the high plains of Wyoming.”

GUESS WHICH ONE IS GETTING LAID.

~ by lycaon on January 25, 2011.