@article {Freeman552380, author = {Benjamin G. Freeman and Micah N. Scholer and Mannfred M. A. Boehm and Julian Heavyside and Dolph Schluter}, title = {Adaptation and latitudinal gradients in species interactions: nest predation in birds}, elocation-id = {552380}, year = {2019}, doi = {10.1101/552380}, publisher = {Cold Spring Harbor Laboratory}, abstract = {The {\textquotedblleft}biotic interactions{\textquotedblright} hypothesis{\textemdash}that stronger interspecific interactions in the tropics drive faster evolution and speciation, giving rise to the latitudinal diversity gradient{\textemdash}has inspired many tests of whether certain biotic interactions are indeed stronger in the tropics. However, the possibility that populations have adapted to latitudinal differences in species interactions, potentially blunting effects on evolutionary rates, has been largely ignored. Here we examine latitudinal patterns in nest predation in Western Hemisphere birds, a canonical example of a strong tropical biotic interaction. Surprisingly, daily rates of nest survival experienced by land birds vary minimally with latitude. Only when controlling for length of nesting period do tropical birds suffer higher predation than temperate zone birds. Tropical birds have evolved particularly long nesting periods, and long nesting periods are generally associated with reduced predation rates. Hence, long nesting periods may be a component of adaptation by tropical birds to a diverse community of nest predators. More generally, we suggest that adaptation to strong biotic interactions can alter observed latitudinal gradients in interaction strength, potentially equalizing evolutionary rates among latitudes. Moving forward, tests of the biotic interactions hypothesis should consider measuring both latitudinal patterns in interaction strength and evolutionary responses to these interactions.}, URL = {https://www.biorxiv.org/content/early/2019/03/23/552380}, eprint = {https://www.biorxiv.org/content/early/2019/03/23/552380.full.pdf}, journal = {bioRxiv} }