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How do crickets get away with being so loud without getting eaten? There are a number of bugs that reproduce by blatantly advertising their location. For instance fireflies advertise their location with physical light and are extremely easy to catch.

How is this evolutionary selected for?

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They don't always 'get away with it'! A study by Pascoal et al. (2014) found that field crickets (Teleogryllus oceanicus) on Oahu and Kauai islands of Hawaii have lost the ability to produce sound after an invasive wasp that is acoustically oriented to prey was introduced to the islands within this century. There are a few mutation to the crickets' wing morphology that produces "flat wings" that cannot make sound. Ordinarily, this mutation would reduce fitness through a reduction in competition for attracting mates. However, the selection pressure from the wasp caused independent mutations for flat winds to sweep through the island to the point that the Kauai population was 96% flat wing.

This example illustrates that the deciding factor between 'getting away' with producing so much noise comes down to the selection balance of attracting more mates or attracting more predators.

Reference: Pascoal, S., Cezard, T., Eik-Nes, A., Gharbi, K., Majewska, J., Payne, E., … Bailey, N. W. (2014). Rapid convergent evolution in wild crickets. Current Biology: CB, 24(12), 1369–1374.

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For loud calls to be stable in large-population evolutionary dynamics, the fitness benefit from the call (e.g., mate attraction) must exceed the fitness costs from the call (e.g., predator attraction).

Individual species can 'solve for' benefit > costs by any number of devious tricks. One classic trick used by noisy insects (e.g., cicadas) is 'predator saturation'. Imagine you're a predator that hunts noisy insects by following their call - any time you find one, you'll eat it - unless you're already so full that you literally can't fit any more insects down your gullet. If the noisy insects have a short breeding season, and are noisy for the whole of that season, then during the season you will very quickly fill up and be unable to eat, but you will only have eaten a tiny fraction of the insect population.

If the predators are already full, the costs of predation risk are very low. The benefits of mate attraction remain as high as ever. In that case, an insect's best strategy is to sing as loud as possible.

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    $\begingroup$ Periodical cicadas are a great example of a noisy prey species with a remarkable predator satiation strategy. $\endgroup$
    – MikeyC
    Sep 18, 2020 at 15:28
  • $\begingroup$ Do you have some citations to go with this answer? Studies which have experimentally / theoretically shown that theory explains what we might see in nature. $\endgroup$
    – user438383
    Sep 20, 2020 at 8:35
  • $\begingroup$ Your explanation of cost/benefit ratio is spot on, but I'm not sure if predators 'being full' is that applicable in nature since that would just increase the predator population. It probably has more to do with relative risk of predation (i.e. it's not that the predator is so full that it stops eating, rather, the predator is just eating your neighbor instead of you). $\endgroup$
    – et is
    Sep 20, 2020 at 13:27
  • $\begingroup$ @etis You're right, I simplified some of the details. Predator saturation also requires that the predator population doesn't grow to the point where it can eat all of the saturating prey: predator populations must be limited by something other than peak prey abundance. Fortunately for the cicadas, there are eleven months per year where their predators aren't stuffed to the gills, and the food supply in those months are what limits the predator population. $\endgroup$
    – bshane
    Sep 21, 2020 at 0:58
  • $\begingroup$ @bshane That definitely makes sense for the cicadas that all emerge and call at the same time. Do you think it still holds for crickets that call consistently throughout much of the year? $\endgroup$
    – et is
    Sep 21, 2020 at 1:03

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