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Happy to share my PhD paper that investigated how predation risk (PR) drives alternative reproductive tactics in mate searching behaviour of tree crickets, and its fitness consequences. Out in @FunEcology today!
https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.13652
Buckle up for an explainer
https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.13652
Buckle up for an explainer
Risk of being eaten by predators scares prey into behaving in ways they would rather not. This means increased vigilance, staying in larger groups, avoiding risky spaces, etc that translates to reduced foraging opportunities or reduced time feeding, often affecting fitness
PR can also affect reproductive behaviour. It may change how you attract and localise mates, thereby influencing how many offspring you leave behind.
In species where males sing to attract females, PR is predicted to drive males to switch to a less conspicuous satellite strategy
In species where males sing to attract females, PR is predicted to drive males to switch to a less conspicuous satellite strategy
Satellite males don't sing but park themselves close to other singing males and attempt to mate with females that are localising the song. They gain the benefits of mating without facing any of the costs!
But does this actually happen in natural populations?!
But does this actually happen in natural populations?!
We addressed this question in a field enclosure experiment using natural populations of tree crickets and their predators, green lynx spiders.
We built large enclosures (6m X 6m), released crickets and spiders in different ratios and recorded behaviour and survival for a week
We built large enclosures (6m X 6m), released crickets and spiders in different ratios and recorded behaviour and survival for a week
We find the cool prediction to be true BUT with interesting consequences!
Males shift from singing to satellite strategy with increasing PR, but this reduces their chances of finding mates. Wait but why would they alter their behaviour in that case?
Males shift from singing to satellite strategy with increasing PR, but this reduces their chances of finding mates. Wait but why would they alter their behaviour in that case?
The answer may lie in survival.
Since we find survival of crickets reducing with increasing PR, we think males prefer to switch to satellite and leave the risky patch with high PR to land in a patch which is safer.
This way they can survive and try again another day.
Since we find survival of crickets reducing with increasing PR, we think males prefer to switch to satellite and leave the risky patch with high PR to land in a patch which is safer.
This way they can survive and try again another day.
How did we know they are performing satellite strategy and not just passively searching for females, you ask?
We ran simulations to compare real male movement with random movement of virtual males and found that real males are directing their movement towards calling males!
We ran simulations to compare real male movement with random movement of virtual males and found that real males are directing their movement towards calling males!
Finally, we find that females do not change their localising behaviour with increasing PR, probably because that would mean they need to continue to stay on in the risky patch.
If you have persisted this far, here's the takeaway: we show that predation risk can be a driver for the evolution of alternative reproductive tactics, but there are interesting sex differences, at least in crickets.
Ok bye
Ok bye
