Damselfish face climate change: Impact of temperature and habitat structure on agonistic behavior

habitat was structurally more complex (Fig 3). After mirror exposure, fishes remained longer in quadrant 1 (i.e. more aggressive) under both temperature regimes. However, fish at 28˚C showed a greater behavioral change (from quadrant 4 to quadrant 1), while fish at 34˚C occu- pied the other quadrants (less aggressive when compared to quadrant 1). Also, fish from com- plex habitat remained longer in quadrant 1 than fish from barren habitat (Fig 3). Aggressive and locomotor behavior differed due to the temperature before mirror exposure and the interactive effect of temperature and habitat complexity after mirror exposure (Two- Way PERMANOVA, Table 3). Before mirror exposure, more threat behavior occurred at 34˚C and more vigilance, immobility and feeding at 28˚C (Fig 4 and Table 4). However, there was a trend to a habitat complexity effect at 34˚C, resulting in more threat behavior in the barren condition and more vigilance in its complex counterpart (Fig 4 and Table 4). After mirror exposure, attack behavior became more frequent (almost absent before mirror exposure) and an integrative effect between temperature regime and habitat complexity was observed (Fig 4 Fig 2. Effects of temperature (28 and 34˚C) and habitat structure (complex and barren) on dusky damselfish mobility (swimming velocity and immobility time) before and after mirror exposure. Combinations of temperature and habitat structure with the same letter above the bars are not statistically significant (p>0.05 in Two-Way ANOVA tests) (For details, see Table 1). Data correspond to average values ±SE.

https://doi.org/10.1371/journal.pone.0235389.g002 Table 2. Repeated Measures ANOVA for comparisons of time spent in each quadrant considering the different temperatures (28 and 34˚C) and environments (complex and barren) in the dusky damselfish before and after mirror exposure. Before mirror (ε – 0.716) After mirror (ε – 0.689) Source DF MS F P MS F P Between subjects Temp. 1 1.17 0.32 0.575 1.86 0.76 0.390 Compl. 1 3.19 0.88 0.357 8.80 3.61 0.067 T x C 1 10.50 2.88 0.100 0.60 0.25 0.624 Error 32 3.65 Within subjects Quadr. 3 181.44 13.90 < 0.001 166.46 16.27 < 0.001 Q x T 3 0.92 0.07 0.942 27.26 2.67 0.075 Q x C 3 2.90 0.22 0.817 1.97 0.19 0.832 Q x T X C 3 47.50 3.64 0.029 33.06 3.23 0.044 Error 96 13.05 10.23 Data were square-root transformed and p-values were subjected to Greenhouse-Geisser correction. Bold p-values correspond to significant effects. Temp./T– temperature; Compl./C–complexity of the habitat; Quadr/Q–quadrant. DF = degrees of freedom. MS = mean squared https://doi.org/10.1371/journal.pone.0235389.t002 PLOS ONE Temperature and habitat structure on damselfish behavior PLOS ONE | https://doi.org/10.1371/journal.pone.0235389 June 30, 2020 6 / 13