NORTH-WESTERN JOURNAL OF ZOOLOGY 14 (1): 71-75 ©NWJZ, Oradea, Romania, 2018 Article No.: e171507 http://biozoojournals.ro/nwjz/index.html

Calling perch selection and body condition in jimi (Anura: ).

Pietro Longo Hollanda DE MELLO1,2*, Guth Berger Falcon RODRIGUES2, Wáldima Alves da ROCHA2 and Reuber Albuquerque BRANDÃO2,3

1. Biodiversity Institute, Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA, 66045. 2. Departamento de Zoologia, Instituto de Ciências Biológicas (IB), Universidade de Brasília, Brasília, Distrito Federal, Brazil, CEP 70910-900. 3. Laboratório de Fauna e Unidades de Conservação, Departamento de Engenharia Florestal, Universidade de Brasília, Distito Federal, Brazil, CEP 70910-900. * Corresponding author, P.L.H. De Mello, E-mail: [email protected]

Received: 10. October 2016 / Accepted: 19. April 2017 / Available online: 29. July 2017 / Printed: June 2018

Abstract. Calling is a key behavior in anuran ecology, associated with individual reproductive success and territory maintenance. Sites that allow better sound propagation, with higher intensity and less energy consumption, are a resource that males will compete for. We used body condition (BC) as a proxy for competitive performance to test the hypothesis that Dendropsophus jimi males with superior BC occupied better perches for calling in a with simple vegetative structure. Because grassy layer density and height are inversely correlated, presumably facilitating sound propagation, we expected a positive correlation between BC and perch height in open-field specialists. We also identified which morphological features were associated with higher perching. In addition, if calling males are depleting energy reserves during the breeding season, they should maintain BC through food consumption. To test this hypothesis, we performed a correlation between stomach volume and food item abundance with BC. We found perch height to be positively correlated with BC. Higher calling males were also characterized by having longer legs, shorter carpus and smaller heads. However, we found no correlation between BC and food intake. We suggest that calling males are depleting previously accumulated energy stocks. Higher calling perches are apparently actively disputed by D. jimi, as superior BC males are using mainly higher perches. We suggest that our findings on the small D. jimi are also expected for other open field Hylinae in the Cerrado.

Key words: advertisement call, body condition, diet, intrasexual competition, morphology, Cerrado.

Introduction morphometric features associated with perching height. For that, we sampled males of Dendropsophus jimi (Napoli & Anuran advertisement calls hold several social roles, such as Caramaschi, 1999) (Fig. 1) from a species poor pond (four promoting spacing among males in a chorus, and attracting anuran species) dominated by grasses, in the Brazilian Cer- reproductive mates (Wells 1977, Wells & Schwartz 2007). rado Savanna (Myers et al. 2000). The lack of congeneric spe- Calling is among the most energetically demanding activi- cies in the pond allowed the locally abundant D. jimi males ties in ectotherms (Taigen & Wells 1985) and its effectiveness to use all possible perch heights, thus releasing this feature depends on efficient signal transmission (i.e. reaching the re- from potential interspecific competition (e.g. Brasileiro et al. ceiver). Therefore, optimization of call efficiency should be 2005, Martins et al. 2006). We expected males with superior under selection in (Crump 1974, Sinsch et al. 2012), and BC to call from higher perches, an indication that intraspeci- males should compete for sites that allow better sound fic competition may be playing a role in intraspecific propagation, higher intensity, and lower energy expenditure partitioning; and to have longer legs, used for both jumping (Wells & Schwartz 1982). Since sound degradation is in- (Choi et al. 2003), or in physical combats (e.g. Noer & Mardi- versely correlated to perch height, calling from higher ansya 2014, Méndez-Narváes & Amézquita, 2014). perches is an alternative to improve call efficiency (Kime et Since anuran metabolic costs increase with calling effort al. 2000, Schwartz et al. 2016). (Taigen & Wells 1985), we additionally tested the hypothesis The competition for resources during the breeding sea- that calling males are using previously stored energy stocks son is common in anurans (e.g. Wells 1977, Arak 1983), and through the breeding season (Jiménez & Bolaños 2012), in- might include aggressive vocalization and/or physical com- stead of maintaining BC via frequent intake of energy, i.e. bats (Wells 1988, Gerhardt & Huber 2002). When such in- food ingestion. To test this hypothesis, we performed a cor- traspecific interactions cannot be directly observed in the relation between stomach volume and food item abundance field, body condition (BC), a measure for the energetic status with BC. If calling behavior is kept by depletion of stocks, of an organism (Jakob et al. 1996, Labocha et al. 2013, but see we expect a lack of correlation and a high frequency of Wilder et al. 2016) can be used as a surrogate for several fit- empty stomachs. ness parameters, such as fighting capacity (Thorpe et al. 1995). The scaled mass index (SMI) (Peig & Green 2009) is one of multiple methods developed to estimate BC (e.g. Ja- Material and methods kob et al., 1996). We chose SMI since MacCracken & Steb- bings (2012) tested this method on anurans and salaman- Study system & sampling We conducted our study in a permanent pond (15°53'52"S and ders, and showed that it does accurately reflect the speci- 47°56'38"W, 1100 m a.s.l.) located in a suburban neighborhood of men’s energy storage, i.e. it’s BC, in these taxa. SMI may Brasília, Brazil. The climate in Brasília is tropical (Köppen’s Aw), thus be used as a proxy for competitive performance, help- with a dry season from April to September, and a rainy season from ing identify patterns that may result from intraspecific com- October to March (Peel et al. 2006). Habitat structure in the pond is petition. simple, with the predominance of a grassy layer over wet soil and Herein, we tested the hypothesis that male BC is posi- scattered bushes surrounding the pond. Although males can call tively correlated with higher perches, and characterized the from grasses, the sparse bushes provide the higher calling perches 72 P.L.H. De Mello et al.

through a linear regression, followed by an evaluation of the whole data set (all specimens) for outliers by examining scatter plots. We chose this method because it has successfully been applied to quan- tify energy storage in (MacCracken & Stebbings 2012), and because it accommodates error in measurements for both ‘M’ and ‘L’, as well as differences in the magnitude of natural variability and measurement error between these variables (see Peig & Green 2009). We performed a linear regression between BC and perch height to test the hypothesis that male BC was positively correlated with better, thus higher, perches. To test if frogs were maintaining calling behavior by depleting previously stocked energy, we performed two general linear models, one between BC and the number of ingested food items, and a second between BC and stomach volume. We determined which morphometric measures were associated with perch height use through a multiple regression with automatic

Figure 1. Male Dendropsophus jimi perching at study locality. model selection, using the single best Akaike Information Criterion Photo: Wáldima Rocha. (AIC) (Burnham & Anderson 2002) in package MASS (Venables & Ripley 2002). To correct for correlation, we represented all variables through PCA axes (Tabachnick & Fidell 2001). We performed all surrounding the pond. Macrophytes are found around and up to analysis using R software (R Core Team 2015). ~1m away from the margin. Water depth can reach ~1m. Dendropsophus jimi is a small hylid (males SVL 17.6 – 20.9 mm) with a green dorsum, typically associated with permanent in Results open areas (Napoli & Caramaschi 1999). This species concentrates its reproductive effort in wet season (Brasileiro et al. 2005) and pro- We captured and analyzed the stomach of 58 Dendropsophus duces free-living tadpoles that live in lentic water bodies (mode 1, jimi males. These males showed snout-vent length (SVL) av- Haddad & Prado 2005). Three other species, including Boana al- bopunctata (Spix, 1824), Leptodactylus fuscus (Schneider, 1799), and erage of 18.78 ± 0.93 mm, and body mass of 37.24 ±7.20 mg. Physalaemus cuvieri (Fitzinger, 1826) were also found in our study Averages and standard deviations of the other morphologi- pond. B. albopunctata could putatively outcompete with D. jimi for cal measures collected are presented in Table 1. As hypothe- perches due to its larger body size (Vieira et al., 2016). However, B. sized, we found a significant positive correlation between albopunctata was never seen calling from Macrophytes, presumably body condition (BC) and perch height (79.24; t = 3.465; p < due to its larger body weight that would not be supported by leaves 0.005). The morphometric variables that best explained the of these plants. B. albopuncatata males were not abundant at the pool, use of higher perches were (AIC = 548.62): Carpus length and the few observed males were scattered along the pond margins. We sampled for four consecutive nights in February, 2013, ob- (CL), tibia length (TL) and head width (HW). CL (- 9.10; t = serving and collecting specimens between 7 pm to 12 pm. Captured 3.791; p < 0.05) and HW (-10.16; t = 3.907; p < 0.05) were in- specimens were preserved in 10% formalin, and later transferred to versely correlated to perch height, while TL (10.385; t = 70% ethanol. All specimens were deposited at the Laboratório de 3.642; p < 0.01) was directly correlated to perch height (Fig. Fauna e Unidades de Conservação (LAFUC) at the University of 2). AIC values for all other possible values are listed in Ap- Brasília. Vouchered specimens’ numbers are presented at Appendix pendix 2. 1. We acquired several phenotypic measures that may serve as prox- ies for individual fitness (Morris 1989, Jakob et al. 1996). We meas- Table 1. Minimum, maximum, mean and standard deviation of mor- ured mass using a precision balance (0.01g), and body size through phometric measurements, mass, body condition (measured snout-vent length (0.01 mm). To determine which morphometric fea- through SMI), and calling perch height for Dendropsophus jimi. tures were associated with perch height, we took the following measurements, using digital calipers (0.01 mm): Snout-vent length Mean ± Minimum – (SVL), tibia length (TL), foot length (FOL), femur length (FEL), car- Variables Standard deviation Maximum pus length (CL), hand length (HL), head width (HW), and radius Humerus length (HL) 3.99 ± 0.58 mm 2.69 – 5.46 mm length (RL). One of the authors (PLHM) took all morphometric Radius length (RL) 3.64 ± 0.43 mm 2.49 – 4.82 mm measurements for all specimens’ pre preservation. Carpus length (CL) 4.87 ± 0.48 mm 3.71 – 5.8 mm We determined perch height using a tape measure and subdi- Femur length (FEL) 8.92 ± 0.87 mm 4.21 – 9.94 mm viding in 10cm intervals, initiating from ground/water level. We ex- Tibia length (TL) 9.52 ± 0.47 mm 8.38 – 10.80 mm amined stomach contents using a stereoscopic microscope, identify- Foot length (FOL) 13.03 ± 0.74 mm 11.16 – 14.15 mm ing Arthropods to Order, whenever possible, and measured all items Head width (HW) 5.61 ± 0.33 mm 4.82 – 6.19 mm to the nearest 0.01 mm using digital calipers. We quantified individ- Snout-vent length (SVL) 18.78 ± 0.93 mm 15.59 – 20.84 mm ual stomach contents, and obtained prey volume per stomach, using Mass 0.37 ± 0.072 g 0.20 – 0.50 g the ellipsoid volume formula (Caldwell & Vitt 1999). To determine Scaled Mass Index (SMI) 0.38 ± 0.14 0.19 – 1.04 the relative contribution of each prey category, we calculated the Perch height 482.7 ± 301.5 mm 0 – 1100 mm importance index for individuals (IRI), following Mesquita et al.

(2006). We present each specimen’s voucher numbers, morphometric We did not find correlation between stomach fullness measurements, mass, BC (as SMI), stomach content, and additional behavioral and habitat data in Appendix 1. and BC, nor between the number of ingested items and BC. From the 58 sampled stomachs, 22 (38%) held food items, Analysis and 36 (62%) presented empty stomachs or plant material. We calculated body condition (BC) through the Scaled Mass Index We found 23 food items belonging to seven taxonomic cate- (SMI) proposed by Peig and Green (2009). The SMI procedure as- gories: Coleoptera (n = 6), Lepidoptera (n = 2), Blattaria (n = sesses the relationship between body mass (‘M’) and SVL (‘L’) 1), Diptera (n = 4), Hemiptera (n = 4), Odonata (n = 1) and Perch height in Dendropsophus jimi 73

fitness to its users (Forrest 1994). We did not find correlation between BC and stomach volume, or with abundance of food items in a specimen’s stomach, thus corroborating our second hypothesis. We also registered a high frequency of empty stomachs (62%), a re- duced number of prey, and a low diversity of food items, a common finding for Dendropsophus species during the re- productive season (e.g. Castro et al. 2016, Solé & Pelz 2007, Jiménez & Bolaños 2012). Therefore, individual BC does not seem to depend on food consumption right before calling ac- tivity (Taigen & Wells 1985), even though it is such an ener- getically demanding activity. It is worth noting that males may maintain their energy stocks through other strategies than continuous food intake, such as by taking periodic pauses between calls (Schwartz et al. 1995), or by avoiding call overlaps with other neighboring calling males (Woller- man 1999). Therefore, our data corroborates the idea that during breeding activities, males focus on calling instead of performing feeding activities (Jiménez & Bolaños 2012), po- tentially depleting previously stocked energy (MacNally

1981). Figure 2. Principal Components Analysis (PCA) of Dendropsophus We suggest that males of D. jimi are competing for better jimi depicting relationships between carpus length (CL), head calling perches, which drives habitat partitioning between width (HW), tibia length (TL) according to perch height (Height). males, and that calling activity is maintained by strategies other than frequent food intake. Such partitioning should be Araneae (n = 5). Specimens had a low diet diversity (H’ = found for other open field Hylinae when interspecific com- 1.792). The average richness of preys found in stomachs petition is absent. Because of the lack of congeneric species, holding food items was 1.79 ± 0.69 taxa per stomach. We and the relatively simple structure of this pond, this is an found Coleoptera in 26.09% of stomachs, representing 28% ideal location for future studies focusing on the effects of in- of ingested items (n = 23). Araneae were found in 21.74% of traspecific competition over habitat partitioning. Season long stomachs, being the second most commonly ingested item, competition and diet studies, as well as direct body storage representing 20% of ingested items. Coleoptera (63) and measurements (e.g. lipid reserve measurements), would Araneae (60.54) also exhibited the highest IRI. Volumetri- provide evidence to corroborate the indirect measurements cally, Araneae (56.39%) was more important than Coleoptera for competition and energy usage that we provide herein. (26.74%).

Discussion Acknowledgments. We thank Fazenda Água Limpa, Universidade de Brasília (UnB), and Renan Bosque for logistic support; Katie Allen, Richard E. Glor and the Herpetology Division of the Calling is a highly energetically demanding activity (Taigen University of Kansas for criticisms and suggestions for the & Wells 1985), with direct fitness implications. Since better manuscript; the Coordenação de Aperfeiçoamento de Pessoal de perches may be scarce, males should compete for sites that Nível Superior (CAPES), which provided fellowships to PLHM and grant a better propagation of sound (Wells & Schwartz GBFR. 1982), such as higher perches. In agreement to this premise, we found a positive correlation between BC and perch height. We also found that males calling from higher perches References had longer legs, as well as shorter carpus and smaller heads in relation to body size. Since BC has been correlated to su- Arak, A. (1988): Sexual dimorphism in body size: A model and a test. Evolution perior fitness (Labocha et al. 2013), and since legs are com- 42: 820-825. monly used during aggressive encounters in anurans (e.g. Brasileiro, C.A., Sawaya, R.J., Kiefer, M.C., Martins, M. (2005): Amphibians of an open Cerrado fragment in Southeastern Brazil. Biota Neotropica 5: 1–17. Wells 1977, Brasileiro et al. 2005, Martins et al. 2006), we hy- Burnham, K.P., Anderson, D.R. (2002): Model Selection and Multimodel pothesize that males with longer legs and superior BC can Inference: A Practical Information-Theoretic Approach. Springer-Verlag, reach, and defend better sites more efficiently. In addition, New York. Caldwell, J.P., Vitt, L.J. (1999): Dietary asymmetry in leaf litter frogs and lizards longer legs may also be used to evade predators through in a transitional northern Amazonian rain forest. Oikos 84: 383–397. long distance jumps (Menin et al. 2005, Toledo et al. 2007). In Castro, I.M., Rebouças, R., Solé, M. (2016): Diet of Dendropsophus branneri contrast to other localities (e.g. Brasileiro et al. 2005, Martins (Cochran, 1948)(Anura: Hylidae) from a cocoa plantation in southern Bahia, Brazil. North-Western Journal of Zoology 12: 159-165. et al. 2006) there is no evidence for interspecific competition Choi, I., Shim, J.H., Ricklefs, R.E. (2003): Morphometric relationships of take-off for perches. Therefore, we suggest that the positive correla- speed in anuran amphibians. Journal of Experimental Zoology 299A: 99–102. tion between BC and perch height is evidence for intraspeci- Crump, M. (1974): Reproductive strategies in a tropical anuran community. Miscellaneous Publications of the Kansas University 61: 1–68. fic competition for better perches, with higher quality males Forrest, T.G. (1994): From sender to receiver: propagation and environmental occupying better perches, as these provide higher adaptive effects on acoustic signals. American Zoologist 34: 644–654. 74 P.L.H. De Mello et al.

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+ Appendix 1 and 2 – 1½ pages

Appendix 1. Specimens' morphometric measurements, calling perch height and habitat, behavior and stomach content. All specimens were deposited at the Laboratório de Fauna e Unidades de Conservação (LAFUC) at Universidade de Brasília. Morphometric measurements are in millimeters (mm). Legend: Vouchered Number = Specimen's number at LAFUC; Sex = Specimen's sex; Mass = Specimen's mass in grams (g); SVL = Snout-vent length; HL = Hand length; CL = Carpus length; FEL = Femur length; TL = Tibia length; FOL = Foot length; HW = Head width; SMI = Scale Mass Index (Peig & Green 2009); Perch Height = Specimen's perched height when first seen, in centimeters (cm); Exposed = Specimens were considered exposed when they were not covered by grasses or leaves when first seen; Calling = Speci- men's behavior when first seen; Microhabitat = Environment in which specimen was first seen: macrophyte, grass, bush, Eriocauleaceae, and water/ground level; Stomach Content = Specimen's stomach could either be empty, contain organic matter or inorganic matter. Whenever possible arthropods were identified to order level.

Voucher Sex SVL Mass HL RL CL FEL TL FOL HW SMI Perch Exposed Calling Microhabitat Stomach Number Heigth content RAB3003 Male 19.94 0.30 5.14 3.32 5.07 9.94 9.33 14.01 6.00 0.19212 40 Yes Yes Grass Empty RAB3004 Male 19.71 0.30 3.83 3.59 4.95 8.92 8.41 11.16 5.75 0.20950 30 Yes Yes Bush Empty RAB3005 Male 20.44 0.40 5.46 4.38 4.68 9.94 10.02 12.85 6.16 0.21294 10 Yes Yes Grass Empty RAB3006 Male 20.84 0.50 4.19 4.14 4.47 9.78 10.04 13.56 5.99 0.23033 30 Yes Yes Grass Empty RAB3007 Male 19.27 0.30 3.42 4.00 5.80 7.55 9.72 13.14 5.66 0.24795 30 Yes Yes Grass Coleoptera RAB3008 Male 19.25 0.30 4.05 3.65 4.61 9.09 8.78 12.36 5.72 0.24987 20 No Yes Bush Hemiptera RAB3009 Male 19.21 0.30 3.56 3.73 4.79 8.47 9.33 12.37 6.19 0.25378 30 No Yes Bush Empty RAB3030 Male 19.21 0.30 3.59 3.68 5.35 9.29 9.85 13.84 6.06 0.25378 100 Yes Yes Bush Organic and Inorganic matter RAB3031 Male 19.15 0.30 4.62 3.78 5.31 8.61 9.51 13.94 5.95 0.25978 50 Yes Yes Bush Empty RAB3040 Male 19.82 0.40 2.69 4.32 4.99 8.57 9.91 13.97 5.82 0.26797 80 Yes Yes Macrophyte Diptera Perch height in Dendropsophus jimi 75

Voucher Sex SVL Mass HL RL CL FEL TL FOL HW SMI Perch Exposed Calling Microhabitat Stomach Number Heigth content RAB3041 Male 19.79 0.40 4.59 4.82 5.24 9.00 10.80 13.42 5.74 0.27102 90 Yes Yes Macrophyte Empty RAB3042 Male 18.92 0.30 3.71 2.98 5.54 8.08 9.15 13.83 5.95 0.28429 30 Yes Yes Macrophyte Diptera RAB3043 Male 19.58 0.40 4.29 3.40 4.38 9.36 10.23 13.56 5.99 0.29347 20 Yes No Macrophyte Empty RAB3044 Male 18.82 0.30 4.97 3.71 4.92 9.94 9.80 12.95 5.78 0.29576 70 Yes Yes Macrophyte Empty RAB3045 Male 18.75 0.30 3.19 4.11 4.14 8.05 9.24 12.52 5.58 0.30410 10 Yes Yes Grass Empty RAB3046 Male 19.40 0.40 4.50 3.36 3.71 8.77 9.92 13.60 5.54 0.31441 80 Yes Yes Grass Aracnidae RAB3047 Male 19.34 0.40 4.29 4.26 4.73 9.40 9.70 13.50 5.73 0.32177 10 Yes Yes Eriocaulaceae Empty RAB3048 Male 19.33 0.40 4.10 3.64 5.35 9.31 10.00 13.50 5.56 0.32301 20 Yes Yes Macrophyte Empty RAB3049 Male 19.31 0.40 3.82 3.48 5.13 9.35 10.00 12.84 5.94 0.32552 10 Yes No Grass Empty RAB3050 Male 18.56 0.30 4.05 3.99 4.93 9.87 9.53 13.67 5.29 0.32812 10 Yes Yes Grass Empty RAB3051 Male 19.80 0.50 3.95 4.20 4.32 8.51 9.31 12.66 4.82 0.33749 50 Yes Yes Bush Empty RAB3052 Male 19.19 0.40 3.88 3.53 5.10 8.93 9.52 13.99 5.47 0.34102 20 Yes No Grass Diptera RAB3053 Male 19.18 0.40 4.14 3.79 5.09 8.77 10.07 13.26 5.84 0.34235 10 No No Grass Inorganic materials RAB3054 Male 19.18 0.40 3.50 3.29 5.69 9.74 9.62 14.01 5.63 0.34235 40 Yes Yes Macrophyte Empty RAB3055 Male 18.35 0.30 3.82 4.05 4.97 4.21 10.04 13.48 5.63 0.35720 10 No No Grass Empty RAB3056 Male 19.06 0.40 3.53 3.72 4.97 9.47 9.77 13.61 5.67 0.35876 110 No No Grass Empty RAB3057 Male 19.05 0.40 2.82 3.37 5.27 8.19 9.74 13.40 5.50 0.36017 30 No No Macrophyte Lepdoptera and Coleoptera RAB3058 Male 19.04 0.40 4.86 3.78 5.19 9.19 9.56 13.88 5.83 0.36159 0 Yes No Flooded Empty RAB3059 Male 19.02 0.40 4.25 3.83 5.24 8.09 10.10 13.38 5.65 0.36443 60 Yes Yes Macrophyte Empty RAB3060 Male 18.99 0.40 4.62 3.42 4.95 9.04 9.57 13.20 5.90 0.36875 60 Yes Yes Macrophyte Coleoptera RAB3061 Male 18.98 0.40 3.81 3.00 5.58 9.01 9.67 14.15 5.99 0.37020 0 Yes Yes Flooded Empty RAB3062 Male 18.96 0.40 3.66 4.24 4.24 8.67 9.01 12.53 5.55 0.37313 20 Yes Yes Grass Diptera RAB3063 Male 18.94 0.40 4.81 4.15 4.85 9.32 9.33 12.97 5.90 0.37608 10 Yes Yes Grass Homoptera RAB3090 Male 18.91 0.40 3.58 3.74 5.33 9.39 9.95 13.49 6.19 0.38055 40 Yes Yes Eriocaulaceae Coleoptera and Hemiptera RAB3091 Male 18.88 0.40 4.92 4.22 5.00 8.82 9.56 12.80 5.40 0.38509 40 Yes Yes Grass Aracnidae RAB3092 Male 18.87 0.40 4.00 3.34 4.08 8.34 9.32 11.96 5.30 0.38662 80 Yes Yes Macrophyte Empty RAB3093 Male 18.15 0.30 4.25 3.87 4.88 8.55 9.34 12.45 5.71 0.38764 70 No Yes Macrophyte Empty RAB3094 Male 18.85 0.40 3.96 3.66 3.72 9.63 8.99 11.41 5.17 0.38969 60 Yes Yes Macrophyte Empty RAB3095 Male 19.41 0.50 3.12 4.19 4.35 9.62 9.59 13.11 5.09 0.39151 50 Yes Yes Macrophyte Empty RAB3096 Male 18.79 0.40 4.68 3.40 5.41 9.19 9.29 13.04 5.69 0.39907 50 Yes Yes Macrophyte Hemiptera RAB3097 Male 19.35 0.50 3.89 3.02 4.17 9.70 9.73 13.06 5.64 0.40066 50 Yes Yes Macrophyte Empty RAB3101 Male 18.68 0.40 4.68 3.63 4.49 9.16 9.43 13.07 5.31 0.41694 20 Yes No Grass Empty RAB3102 Male 17.97 0.30 4.80 3.00 5.20 9.72 9.90 13.58 5.68 0.41757 60 No Yes Macrophyte Empty RAB3103 Male 17.90 0.30 3.17 3.62 5.63 9.79 8.80 11.75 5.74 0.42991 80 Yes No Macrophyte Vegetal matter RAB3104 Male 17.85 0.30 3.45 3.50 4.80 9.11 8.72 12.03 5.73 0.43898 80 Yes Yes Macrophyte Empty RAB3105 Male 18.53 0.40 4.01 3.72 4.59 7.89 9.56 13.33 5.31 0.44280 90 Yes Yes Macrophyte Empty RAB3106 Male 18.46 0.40 4.08 3.51 4.56 8.85 8.97 11.24 4.92 0.45549 60 Yes Yes Macrophyte Empty RAB3107 Male 18.99 0.50 4.27 2.99 5.37 9.64 10.38 13.69 5.25 0.46094 100 No Yes Macrophyte Empty RAB3108 Male 16.65 0.20 3.69 2.91 4.70 7.89 8.38 11.80 4.85 0.49194 80 No Yes Macrophyte Aracnidae RAB3109 Male 18.23 0.40 4.14 3.48 4.98 9.01 9.28 12.36 5.95 0.50016 110 No Yes Macrophyte Microlepidoptera RAB3110 Male 18.73 0.50 3.73 3.79 3.89 9.29 9.67 12.61 5.25 0.51089 90 No Yes Bush Empty RAB3111 Male 18.15 0.40 3.80 3.78 4.88 9.34 9.21 13.58 5.77 0.51685 70 Yes Yes Macrophyte Aracnidae RAB3112 Male 17.36 0.30 3.79 3.58 4.16 8.94 8.93 12.35 5.40 0.54033 40 Yes Yes Bush Inorganic matter RAB3113 Male 17.32 0.30 3.36 2.87 5.08 9.67 9.51 13.66 5.58 0.54971 60 Yes Yes Bush Empty RAB3114 Male 17.71 0.40 3.41 3.72 4.29 8.40 9.43 12.73 5.11 0.62073 70 Yes Yes Grass Odonata RAB3115 Male 17.87 0.50 4.55 3.42 5.24 9.06 9.85 13.26 5.72 0.72554 30 No Yes Macrophyte Empty RAB3116 Male 15.59 0.20 3.55 2.49 5.12 8.49 8.79 12.12 5.12 0.80372 80 Yes Yes Macrophyte Coleoptera RAB3117 Male 15.90 0.30 3.31 3.52 4.81 7.80 9.53 12.42 5.09 0.40839 50 No Yes Macrophyte Organic and Inorganic matter

Appendix 2. All results of multiple regression with automatic model selection using Akaike Information Criterion (AIC). Legend: Mass = Specimen's mass in grams (g); SVL = Snout-vent length; HL = Hand length; CL = Carpus length; FEL = Femur length; TL = Tibia length; FOL = Foot length; HW = Head width; Perch Height = Specimen's perched height when first seen, in centimeters (cm).

Models AIC (1) Perch height ~ scale(CL) + scale(TL) + scale(HW) 382.03 (2) Perch height ~ scale(HL) + scale(CL) + scale(TL) + scale(HW) 382.87 (3) Perch height ~ scale(SVL) + scale(HL) + scale(CL) + scale(TL) + scale(HW) 384.43 (4) Perch height ~ scale(SVL) + scale(HL) + scale(CL) + scale(FEL) + scale(TL) + scale(HW) 386.30 (5) Perch height ~ scale(SVL) + scale(HL) + scale(RL) + scale(CL) + scale(FEL) + scale(TL) + scale(HW) 388.09 (6) Perch height ~ scale(SVL) + scale(HL) + scale(RL) + scale(CL) + scale(FEL) + scale(TL) + scale(FOL) + scale(HW) 390.07 (7) Perch height ~ scale(SVL) + scale(Mass) + scale(HL) + scale(RL) + scale(CL) + scale(FEL) + scale(TL) + scale(FOL) + scale(HW) 392.07