Reinforcement of Female Mating Preferences in Sympatric vs. Allopatric Populations of Lucania goodei and L. Parva

Low fitness of hybrid offspring can generate selection on mate preferences so individuals avoid mating with heterospecifcs. This process is known as reinforcement and is observed as increased behavioral isolation in areas of sympatry compared to allopatry. We performed female-choice behavioral trials in which females of Lucania parva and Lucania goodei were allowed to choose between conspecific or heterospecific males. We tested females from both sympatric and allopatric populations using a novel female choice assay. Measures of time spent with each male revealed that females of sympatric populations prefer their own species significantly more often than females from allopatric populations. This pattern of preference was seen in both L. parva and L. goodei females. This shows that females prefer males of their own species only when from populations where there is the opportunity for hybridization. Our data suggests that reinforcement of female mate preference has occurred in sympatric populations of L. parva and L. goodei.Ope

Between population male mating trial data

This file contains association time (in seconds) for L. parva males choosing between females from their own population or a foreign population. Focal males were from populations sympatric with L. goodei or allopatric. Data from Figure 4, Figure 5, and Figure A2

Data from: Behavioral isolation due to cascade reinforcement in Lucania killifish

Reinforcement occurs when behavioral isolation is strengthened between species due to selection against hybridization in sympatry. Mate preferences and their target traits may change in sympatry as a consequence of reinforcement. This can potentially generate further behavioral isolation within species if sympatric populations evolve extreme preferences or traits that cause them to reject individuals from foreign populations as mates or be rejected as mates. This process is known as cascade reinforcement. We measured behavioral isolation between sympatric and allopatric populations of Lucania killifish to determine whether isolation evolves due to reinforcement between species and whether reinforcement affects preferences within species, consistent with the cascade reinforcement hypothesis. We measured mate preferences in both sexes between species (Lucania parva vs. Lucania goodei) and within species (among populations of L. parva). Between species, both male and female preferences for conspecifics were highest in sympatric populations. Within species, L. parva females from sympatric populations preferred their own native males over foreign males. Allopatric L. parva females and all L. parva males showed no preferences within species. Within species, behavioral isolation showed no association with ecological variables, such as salinity. Thus, reinforcement is a primary factor generating behavioral isolation in Lucania killifish, creating strong preferences in both sexes among species and leading to cascade reinforcement of female mate preference within species

Data from: Behavioral isolation due to cascade reinforcement in Lucania killifish

Reinforcement occurs when behavioral isolation is strengthened between species due to selection against hybridization in sympatry. Mate preferences and their target traits may change in sympatry as a consequence of reinforcement. This can potentially generate further behavioral isolation within species if sympatric populations evolve extreme preferences or traits that cause them to reject individuals from foreign populations as mates or be rejected as mates. This process is known as cascade reinforcement. We measured behavioral isolation between sympatric and allopatric populations of Lucania killifish to determine whether isolation evolves due to reinforcement between species and whether reinforcement affects preferences within species, consistent with the cascade reinforcement hypothesis. We measured mate preferences in both sexes between species (Lucania parva vs. Lucania goodei) and within species (among populations of L. parva). Between species, both male and female preferences for conspecifics were highest in sympatric populations. Within species, L. parva females from sympatric populations preferred their own native males over foreign males. Allopatric L. parva females and all L. parva males showed no preferences within species. Within species, behavioral isolation showed no association with ecological variables, such as salinity. Thus, reinforcement is a primary factor generating behavioral isolation in Lucania killifish, creating strong preferences in both sexes among species and leading to cascade reinforcement of female mate preference within species

Latency to mate between species

Latency to mate (in days) when Indian River L. parva (IR-sympatric) were paired with Blue Springs L. goodei (BS-allopatric). Data for Figure A5

Between species mating trial data

This file contains the data for time spent with conspecific (Con) or heterospecific (Het) mates when focal fish had the choice between both. Time measured in seconds (out of 600 second trials). Allopatric and Sympatric focal fish compared. Data for Figure 2 of the paper

Between population egg laying data 2 hours

Number of eggs female L. parva laid with males from their own or foreign populations over a 2 hour period with each male. Data for Figure 6

Male morphology

Standard length and total anal fin area as measured from pictures of L. parva (IR,SJ,GC,LB) and L. goodei (UB) males. Data for Figure A4

Between population egg laying data 10 days

Number of eggs laid over 10 days for sympatric Indian River (IR) females and allopatric Texas (TX) females in no-choice trials. Data for Figure A3

Between population female mating trial data

This file contains association time (in seconds) for female L. parva given the choice between males of their own population or males of a foreign population. Foreign populations could either be from the same salinity environment (ecology) or different salinity. Females came from populations were either sympatric with L. goodei or allopatric. Data for Figure 3 and Figure 5