Herpetology Notes, volume 8: 633-641 (2015) (published online on 20 December 2015)

Contributions to the reproductive biology and behaviour of the dotted reed , guttulatus, in southern-central Ivory Coast, West Africa

Akoua Michèle Kouamé1, N’Goran Germain Kouamé2,*, Jean Christophe Béhibro Yao N’Gatta Konan1, Abouo Béatrice Adepo-Gourène1 and Mark-Oliver Rödel3,*

Abstract. We studied the reproductive behaviour of Hyperolius guttulatus in swampy areas of the Azagny National Park, southern-central Ivory Coast. Males congregated in large choruses almost every night around breeding ponds while the number of females per night was comparatively small. We observed a significant sexual size dimorphism. While most reproducing H. guttulatus were encountered at the beginning of the rainy season in mid-April, the breeding period extended more or less continuously until October in swamps of various types. The maximum number of eggs per clutch was 414. Most calling male H. guttulatus were well concealed situated at heights from 109 to 143 cm above ground, on that grew on land as well as plants emerging from water.

Keywords. Anura, Azagny National Park, Côte d’Ivoire, Hyperolius guttulatus, reproductive behaviour, Upper Guinea.

Introduction most other African Hyperolius have received little attention concerning their breeding behaviour. This The Hyperolius Rapp, 1842 is one of the most could be due to the assumption that most members of diverse African anuran genera, most of them exhibiting the genus exhibit very similar reproductive strategies pronounced colour dimorphism (Schiøtz, 1967, 1999; which consist of either depositing eggs under water, Bell and Zamudio, 2012). From West Africa currently or attached to vegetation at varying heights above the 28 Hyperolius are known (Schiøtz, 1967, 1999; surface of the water (Schiøtz, 1967). The former egg Frost, 2015). Although the reproductive behaviour deposition behaviour is observed in savannah species of some southern African species has been studied in and presumably this is necessary to avoid desiccation detail, particularly by S.R. Telford, N.I. Passmore, M.L. of the eggs (Rödel, 2000). Forest species, in contrast, Dyson, P.J. Bishop and their co-workers (e.g. Telford usually attach their eggs on leaves above water. For et al., 1989; Bishop et al., 1995; Henzi et al., 1995), some West African species, several outstanding natural history observations including sex change, annual population cycles and other various behavioural and morphological and physiological adaptations to survive

1 Nangui Abrogoua University, Pôle de Recherche Pêche harsh conditions in West African savannahs have been et Aquaculture, UFR-SN, 02 BP 801, Abidjan 02, Côte reported (Grafe and Linsenmair, 1989; Spieler, 1997; d´Ivoire; Linsenmair, 1998 and papers cited therein; Grafe et 2 Jean Lorougnon Guédé University, UFR-Environment, al., 2002; Lampert and Linsenmair, 2002; Rödel et al., Department of Biology and Physiology, , BP 2006). 150, Côte d´Ivoire; Males of the dotted reed frog, Hyperolius guttulatus 3 Museum für Naturkunde, Leibniz Institute for Evolution Günther, 1858, exhibit striking colour-patterns (Fig. and Biodiversity Science, Invalidenstr. 43, 10115 Berlin, Germany. 1; Schiøtz, 1967, 1999). During the breeding season * Corresponding author e-mails: [email protected], this species is encountered in larger choruses in larger [email protected] forest ponds and swamps where it breeds (Schiøtz, 634 Akoua Michèle Kouamé et al.

Figure 1. Colour pattern variation of male Hyperolius guttulatus from Azagny National Park, Ivory Coast, during the breeding season: a–d (collection numbers: phase J: a= MK001; b= MK002; c= MK003; d= MK008); e–h (phase F: e= MK006; f= MK007; g= MK010; h= MK011). Contributions to reproductive biology and behaviour of Hyperolius guttulatus 635

1967; Rödel, 2000). Although this is a common West only small agricultural activities were tolerated; site 3 African species typical of the forest-savannah transition was inside the park. The site 1 (5.25° N ‒ 4.80° W; 21 zone, to our knowledge, published information on the m a.s.l) covered 1.5 ha within a swampy area dominated reproduction of this species is sparse (e.g. Schiøtz, by a rice field and bordered by corn (Zea mays) and an 1967; Rödel, 2000). old cocoa plantation. The site 2 (5.23° N ‒ 4.79° W; 13 The Azagny National Park (ANP) in southern-central m a.s.l.) approximated 4 ha and was likewise situated Ivory Coast is characterized by swamps of various in a heavily cultivated swampy area, i.e. rice fields, types, covering two-thirds of the park (Lauginie, 2007). and under logging pressure. However, good stands It thus seemed to be a very suitable area to study the of Mitragyna ciliata (Rubiaceae) were encountered reproduction of the dotted reed frog. The purpose of close to water. Most parts of the water surface were our survey was to gain additional information about the covered by various poaceaen grasses and other herbs. reproductive biology and behaviour of this species. The third site (site 3: 5.27° N ‒ 4.64° W; 10 m a.s.l.) was characterized by the dominance of floating aquatic Material and Methods plants (Nymphaea spp.), various Poaceae and other Study area. A survey was conducted in the Azagny herbs, all within a swampy area, situated about 200 m National Park (ANP). The park covers 21,850 ha and from littoral savannah woodland. is located 130 km west of Abidjan in the coastal part Our searching techniques included acoustic and visual of Ivory Coast. The southern sector of ANP consists encounter surveys between 18:00‒22:00 GMT. Calling of a vast low-lying swamp, overlooked in the north by sites were defined as: 1) stands of (only Mitragyna a low plateau (Lauginie, 2007). This lowland swamp ciliata), 2) corn (Zea mays) and 3) poaceaen grasses and forest has a mean annual temperature of 26°C; the herbs. In all three sites calling males of the dotted reed mean annual precipitation is 1,664 mm (Eldin, 1971). frog were actively searched. Recorded data included The equatorial-type climate (Eldin, 1971; Kouamé et abundance (number of males encountered), and type al., 2010) includes a long rainy season with the highest and heights of calling sites. During the night we peaks in precipitation between April and mid-July, and marked all calling sites with coloured plastic tape and a long dry season from December to April. A short height above the ground was measured the following rainy season extends from mid-September to November morning. After capture, were measured and sexed. and a short dry season extends from mid-July to mid- Fifteen vouchers were preserved, all other specimens September. The vegetation is diverse and mostly were released. Morphometric measures were taken by comprises swamps of various types. The swamp-forests, one person with a dial calliper (accuracy ± 0.5 mm). in which Raphia palms are common, cover two-thirds of Measurements were presented as means ± standard the park. Further vegetation types are inundated riverine deviations. It was not always possible to obtain all data forest, relatively small areas of moist evergreen forest from each individual and sample size therefore differs on areas of higher ground, and mangrove (principally among analyses. Other characters recorded included Rhizophora racemosa and Avicennia africana). There colour pattern variation following the definitions by is also some littoral savannah woodland in which the Schiøtz (1967). palm Borassus aethiopum is a conspicuous element To make sure that clutches of H. guttulatus could not (Lauginie, 2007; Kouamé et al., 2008). The south- be confused with these of other sympatric reed frogs western and south-eastern parts of ANP are subject in field, we collected all couples in axillary amplexus to the influence of brackish water backflow from the and kept each in a plastic aquarium (25×15 cm, 16 cm Bandama River and the Ebrié lagoon, respectively. depth) until eggs were deposited. For each female we Field data. Field work was done in 2014 by three determined clutch size and egg diameters (accuracy ± people from April 18th to 26th, hence in the beginning 0.5 mm) laid in the aquaria. of the long rainy season, and from October 9th to 21st To avoid re-counting individuals, frogs not collected in the short rainy season. Further data in the same area as vouchers were released on the next day at their were collected by J.C.B.Y.N. Konan from May 11th respective sites of capture and marked by toe clipping to September 25th 2013. A hand-held GPS receiver following the recommendations of Grafe et al. (2011). (Garmin etrex 20) was used to record the geographical Vouchers (see Appendix) were euthanized in a 1,1,1- positions of all study sites. We investigated three sites: Trichloro-2-methyl-2-propanol hemihydrate solution, sites 1 and 2 were situated in the park buffer zone where thereafter preserved in 70% ethanol, and deposited in 636 Akoua Michèle Kouamé et al. the Laboratory of Environment and Aquatic Biology at Male phase F ‒ The dorsum colour varied from black the Nangui Abrogoua University, Abidjan, Ivory Coast. with large round or oblong yellow spots, or more or Statistical analyses were performed with Statistica less bluish green to dark brown with round or oblong Version 7.1. Because values were not distributed orange spots. The light spots were small to very small normally (Kolmogorov-Smirnov test), we used non- and numerous. Discs on toes and fingers were red to parametric tests for subsequent analyses. reddish. Some toe-tips were slightly greenish. The iris was bluish grey (Figs. 1 e‒h). Females exhibited similar Results colourations as phase F males (Figs. 2c, d). We captured and measured 8 females (all of phase F) Males and females of H. guttulatus that were captured and 77 males (phase J: n= 45; phase F: n= 32) of H. in amplexus were observed towards the beginning of guttulatus (Table 2). Snout-urostyle-lengths (SUL) in the long rainy season (mid-April) and in the short rainy females varied from 33.0–37.0 mm (mean ± sd: 34.2 ± season (October). However, previous field work showed 1.3 mm). SULs in males of phase J varied from 28.5– that the dotted reed frog also reproduce in the dry season 36.0 mm (32.4 ± 1.5 mm); SULs in males of phase F (Table 4). During all survey days, frogs were active ranged from 27.0–35.5 mm (32.3 ± 1.7). The Bonferroni between 18:00‒22:00 GMT. The observation periods adjusted p-values resulting in pairwise comparisons of all recorded frog colour morphs, calling males and indicate that SULs of females were significantly larger abundances per site are summarized in Table 1. We than those of phase J males (p= 0.010) and phase F always observed a large range of colour morphs (Fig. 1), males (p= 0.012). Males of the two colour morphs did all assignable to the phase J and phase F sensu Schiøtz not differ in size (p= 1.000; n= 85; Fig. 3). (1967). All frogs had a distinct dark canthal stripe. We recorded a total of seven couples; three males Male phase J ‒ The dorsal surface was either dull were of phase J while four males were of phase F (Table bluish green (Fig. 1a) to faded yellowish with some 3). The SULs of these phase J males ranged from 32‒34 black spots (Fig. 1b) or brownish with very small and mm (mean ± sd: 33.0 ± 1.0 mm), whereas the size of numerous dark brown spots (Fig. 1c) to light brown the respective females varied from 33.5‒37 mm (mean with dark reddish spots. A conspicuous light stripe ± sd: 35.2 ± 1.8 mm). Concerning the four amplectant situated dorsally to the dark canthal stripe continued males of phase F, they measured between 27.0‒33.5 behind the eye as a light dorsolateral stripe to the groin mm SUL (mean ± sd: 31.6 ± 3.1 mm). The size of their (Fig. 1d). The discs on toes and fingers were coloured females ranged from 34.0‒35.0 mm (mean ± sd: 34.2 bluish green, to yellowish. Some toe-tips were slightly ± 3.1 mm). brownish. The iris colour varied from a golden gleam to Between 18‒26 April 2014 we recorded five couples light brownish (Figs. 1 a–d). at site 1 (Figs. 2c, d), all sitting on Z. mays. One pair was

1 Table 1. ObservationTable periods 1: Observation of Hyperolius periods guttulatus of Hyperolius in Azagny guttulatus National in Park. Azagny Shown National are capture Park. numbersShown are according to sex, colour morphs and calling males per site. 2 capture numbers according to sex, colour morphs and calling males per site.

Observation periods Sex/Colour morphs Site1 Site 2 Site 3 Total Counted calling males 37 56 4 97 Male ph-J (measured) 29 16 0 45 18–26 Apr. 2014 Male ph-F (measured) 8 23 0 31 Females (measured) 5 2 0 7 Counted calling males 11 19 9 39 Male ph-J 0 0 0 0 9–21 Oct. 2014 Male ph-F (measured) 0 0 1 1 Females (measured) 0 0 1 1 3

4

1 Contributions to reproductive biology and behaviour of Hyperolius guttulatus 637 Table 2. Morphometric measures (mm) of Hyperolius guttulatus from Azagny National Park. Given are range (Min-Max), mean and standard deviationTable (x ± 2. sd). Morphometric Abbreviations: measures SUL= snout-urostyle-length;(mm) of Hyperolius guttulatus HW= head from width Azagny measured National directly Park. behind Given the are eyes; range FL= (Min-Max), femur length; mean TL= tibia and standard deviation (x ± sd). Abbreviations: SUL= snout-urostyle-length; HW= head width measured directly behind the eyes; length; FTL= foot length including longest toe; ED= horizontal eye-diameter; IOD= inter-orbital distance; EN= distance from anterior corner of FL= femur length; TL= tibia length; FTL= foot length including longest toe; ED= horizontal eye-diameter; IOD= inter-orbital the eyedistance; to nostril; EN= ES= distance distance from from anterior anterior corner corner of of the the eye eye to to nostril; the snout-tip; ES= distance TD= horizontal from anterior tympanum-diameter corner of the eye (TD); to the IND= snout-tip; inter-nostril TD= horizontal tympanum-diameter (TD); IND= inter-nostril distance; ph-F= phase F; ph-J= phase J. distance; ph-F= phase F; ph-J= phase J.

SUL HW FL TL FTL ED IOD EN ES TD IND

females Min-Max 33.0-37.0 12.0-13.5 14.0-17.0 16.0-19.0 21.0-26.0 4.0-5.5 8.0-9.5 3.0-4.5 5.0-6.5 2.0-3.5 3.0-4.0 (N = 8) x ± sd 34.2 ± 1.3 12.7 ± 0.5 14.7 ± 1.0 17.8 ± 0.9 23.6 ± 1.5 4.4 ± 0.6 8.6 ± 0.6 3.8 ± 0.6 5.6 ± 0.5 2.4± 0.5 3.4 ± 0.4

male ph-J Min-Max 28.5-36.0 10.0-13.0 12.5-16.0 15.0-18.0 21.0-24.0 3.5-5.0 6.0-9.0 2.5-4.0 4.0-6.0 1.5-2.5 2.0-4.0 (N = 45) x ± sd 32.4 ± 1.5 11.5 ± 0.7 13.9 ± 0.8 16.4 ± 0.8 22.4 ± 0.9 4.3 ± 0.4 8.0± 0.6 3.3 ± 0.4 5.1 ± 0.5 2.1 ± 0.2 3.1 ± 0.4

male ph-F Min-Max 27.0-35.5 9.5-13.0 13.0-16.5 14.0-18.5 18.0-24.0 4.0-5.5 5.5-9.0 3.0-4.0 4.0-6.5 2.0-2.5 3.0-4.5 (N = 32) x ± sd 32.3 ± 1.7 11.8 ± 0.9 14.4 ± 0.9 16.7 ± 1.1 22.3 ± 1.2 4.5 ± 0.4 7.7 ± 0.8 3.4 ± 0.4 5.2 ± 0.5 2.2 ± 0.2 3.2 ± 0.3

found at site 2 on the underside a large leaf of M. ciliata put each of them in artificial conditions into aquaria in above the water. Another pair was recorded between order to record their respective eggs. Unfortunately, only the leaves of Nymphaea sp. on the water surface at site three of the females laid eggs in captivity, on the upper 3 on 14 October 2014. Sympatric species encountered side of the aquaria. The eggs had a dark and light green at the three sites were H. concolor concolor, H. pole, surrounded by a thin transparent capsule. Clutch 2 fusciventris and members of the H. picturatus-complex. and female sizes as well as egg diameter measurements As these species were in vast number at the same sites are provided in Table 3 and the seven couples are part of as the dotted reed frog, we did not count eggs of our the overall sampling numbers (i.e. Table 2), observed at focal species in the field to avoid the risk of mistaking heights ranging between 30‒141 cm (mean ± sd: 117.1 clutches of congenerics. Instead, we captured all the ± 39.0 cm). seven encountered H. guttulatus couples in the field and

Table 3. Colour morphs of couples encountered in amplexus and clutch of Hyperolius

guttulatus from Azagny National Park, Ivory Coast. All females were of phase F; given are

Table 3. snout-urostyle-lengthColour morphs of couples (SUL) encountered of couple in amplexus(male and and female), clutch of clutch Hyperolius size guttulatus(egg #) and from eggs Azagny size National Park, Ivory Coast. All females were of phase F; given are snout-urostyle-length (SUL) of couple (male and female), clutch size (egg (egg diameter) from aquaria given as mean ± standard deviation (n= number of measured #) and eggs size (egg diameter) from aquaria given as mean ± standard deviation (n= number of measured eggs per clutch). Measurementseggs per are clutch).given in mm.Measurements are given in mm.

Couples Male SUL Female SUL Egg # Egg diameter (measured with jelly) Male phase-J 33.0 35.0 259 1.48 ± 0.17, n = 102 Male phase-J 32.0 33.5 414 1.44 ± 0.08, n = 101 Male phase-J 34.0 37.0 - - mean ± sd: 33.0 ± 1.0 35.2 ± 1.8 Male phase F 27.0 34.0 333 1.47 ± 0.12, n = 102 Male phase F 33.5 35.0 - - Male phase F 33.0 34.0 - - Male phase F 33.0 34.0 - - mean ± sd: 31.6 ± 3.1 34.2 ± 0.5

3 638 Akoua Michèle Kouamé et al.

Figure 2. Calling Hyperolius guttulatus males (a, b), and couples in amplexus (c, d) from Azagny National Park.

Hyperolius guttulatus males started to call on different comprised individuals of phase J and F colour morphs plants at dusk (at about 18:00) and kept on calling (sensu Schiøtz, 1967), matching earlier descriptions beyond 22:00 GMT. We registered the calling heights (Schiøtz, 1967, 1999; Rödel, 2000). Phase J colour of 76 of the 77 dotted reed frog males on Z. mays, M. morphs characterize sub-adult individuals and some ciliata, other Poaceae and herbs while one non-active mature males with colouration varying from dull bluish male was observed on the water surface. No differences green (Fig. 1a) to faded yellowish with some black spots in calling site choice or height were observed between (Fig. 1b) or brownish with very small and numerous dark both male colour morphs (Table 5; MWU: Z ≤ -0.2683, brown spots (Fig. 1c) to light brown with dark reddish p ˃0.05; n= 76). Males of both colour morphs were spots. The phase F colour morph corresponds to females registered calling on the same plants. On a total of 14 and some mature males, where colouration ranges from plants, we recorded a mean of 3.8 (± 1.2, range: 2‒5) black with large round or oblong yellow spots, to more calling males per . Other anurans encountered in or less bluish green to dark brown with round or oblong syntopy with H. guttulatus were Afrixalus dorsalis, orange spots (e.g. Figs. 1 e–h). While all mature females H. concolor concolor, members of the H. picturatus- changed from a juvenile colour morph to phase F, some complex and H. fusciventris. recorded males retained the juvenile J phase (Schiøtz, 1999). Discussion Although several papers investigated the distribution, We focused on the reproductive behaviour of the dotted evolution, as well as the ontogenetic development and reed frog in Azagny-National Park (ANP), southern- inheritance of sexual dichromatism in Hyperolius (e.g. central Ivory Coast. The observed H. guttulatus males Richards, 1981, 1982, 1976; Veith et al., 2009; Bell Contributions to reproductive biology and behaviour of Hyperolius guttulatus 639

Table 4. Survey periods of the dotted reed frog in Azagny is possible because H. guttulatus chooses large water Table 4. Survey periods of the dotted reed frog in Azagny National Park. Given are recorded National Park. Given are recorded couples at sites 1, 2 and bodies (Schiøtz, 1967; Rödel, 2000), which are persistent 3couples (see text). at sites 1, 2 and 3 (see text). year round. These water bodies, i.e. swamps of various types, cover two-thirds of the ANP (Lauginie, 2007). Surveyed periods couples at site 1 couples at site 2 couples at site 3 While a few Hyperolius spp. seem to be “explosive” 11–23 May 2013 1 5 0 or intermediate between “explosive” and “prolonged” 12–23 Jun. 2013 0 2 0 breeders (e.g. Lötters et al., 2004), H. guttulatus is a 18–27 Jul. 2013 0 3 0 typical “prolonged breeder” like most other reed frogs 16–26 Aug. 2013 0 2 0 (Schiøtz, 1967, 1999; Rödel et al., 2006; Wells, 2007). 14–25 Sep. 2013 0 1 0 At Ananda in eastern Ivory Coast, Rödel (2000) found

18–26 Apr. 2014 5 1 0 more females than males of the dotted reed frog, all 9–21 Oct. 2014 0 0 1 in bushes sitting at heights of 1‒2 m on the edge of a very large pond. In contrast we observed the usual male-biased sex ratio of reed frogs at breeding sites, with males congregating in large numbers almost every night in choruses around the breeding ponds, while the number of females was comparatively small. In our study area, H. guttulatus calling sites comprised plants at and Zamudio, 2012), the evolutionary significance the water’s edge (Z. mays) and plants emerging from the of this variability is still largely unknown. Stewart water (M. ciliata). On both plant types, males vocalized, (1974) suggested for another African frog group, the well concealed, at heights up to 143 cm, matching genus Phrynobatrachus, that diurnal species may profit published data (Schiøtz, 1967, 1999; Rödel, 2000). The from colour variability as visually hunting , i.e. birds, have more difficulties to learn a particular prey pattern. Although, Hyperolius species are all active at night, in particular males of various species, including H. guttulatus, are often sitting relatively exposed close to breeding sites during the daytime (MOR pers. obs.). Males are usually the more variable and more conspicuous sex in Hyperolius as well. Stewart’s (1974) hypothesis thus seems reasonable but still needs to be tested. Additionally it is possible that at least some colour morphs may camouflage the frog from predators. Our morphological measurements were all within the known range for adult H. guttulatus (Schiøtz, 1967; Table 2). Females were significantly larger than males, a pattern that was already reported from southern Nigeria (Luiselli et al., 2004). Schiøtz (1967) reported a clutch comprising 250 eggs and here we document a new maximum clutch size of up to 414 eggs. We expected to see, as in many other anuran species (e.g. Trauth, 4 1989; Salerno and Pauly, 2012), a correlation between the SULs of females and their respective clutch sizes and indeed the largest female also laid the largest clutch, however, our sample size was too small to formally test for such correlation. Figure 3. Snout-urostyle lengths of Hyperolius guttulatus While most reproducing H. guttulatus were from Azagny National Park. Given are median values (black encountered at the beginning of the rainy season in mid- dot), 25 and 75% quartile (upper and lower edge of box) and April, the breeding period extended until October. Some range (error bars; hollow points are statistical outliers) of data indicate that the dotted reed frog also breeds during SULs of males of phase J and F, and females. Females were the dry season (Table 4). This continuous reproduction significantly larger than both male morphs (J and F). 640 Akoua Michèle Kouamé et al. Table 5. Calling sites and their heights used by male Hyperolius guttulatus from Azagny Table 5. Calling sites and their heights used by male Hyperolius guttulatus from Azagny National Park. Given are range (Min‒ National Park. Given are range (Min௅Max), mean and standard deviation (x ± sd). Compared Max), mean and standard deviation (x ± sd). Compared are values of the two different colour morphs (see text) and Mann-Whitney U-test value. are values of the two different colour morphs (see text) and Mann-Whitney U-test value.

Calling heights (cm) Calling sites Males J Males F 120–143 (129.9 ± 6.2) 125–140 (131.3 ± 4,8) Zea mays Mann-Whitney: U = 103.00; Z = -0.4796; p = 0.632 111–128 (119.6 ± 5,7) 109–133 (120.5 ± 6.1) Mitragyna ciliata Mann-Whitney: U = 103.500; Z = -0.2683; p = 0.788 103–114 (107 ± 4,3) 105–111 (108 ± 3.1) Poaceae and herbs Mann-Whitney: U = 5.000; Z = -0.7463; p = 0.453 

assumption that most members of the genus exhibit and call intensity: female choice in the Painted Reed Frog, very similar reproductive strategies consisting of either Hyperolius marmoratus. Behaviour 132: 721–731. depositing eggs under water, or attached to vegetation at Eldin, M. (1971): Le climat. In: Le Milieu Naturel de la Côte d’Ivoire, p. 73–108, Avenard, J.M., Eldin, M., Girard, G., varying heights above the surface of the water (Schiøtz, Sircoulon, J., Touchebeuf, P., Guillaumet, E., Adjanohoun, E., 1967), fits well with the dotted reed frog in ANP. Our Perraud, A., Eds., Paris, ORSTOM. observations indicate that most male H. guttulatus prefer Frost, D.R. (2015): species of the World: an online calling sites covered by large leaves. Furthermore, they reference. Version 6.0. Available at: http://research.amnh.org/ preferred mainly elevated plants with large leaves such herpetology/amphibia. Last accessed on 30 May 2015. as Z. mays and stands of M. ciliata. Both types of plants Grafe, T.U., Linsenmair, K.E. (1989): Protogynous sex change in were only encountered at site 1 (corn field: Z. mays) and the reed frog Hyperolius viridiflavus. Copeia 1989: 1024–1029. Grafe, T.U., Döbler, S., Linsenmair, K.E. (2002): Frogs flee from site 2 (numerous stands of M. ciliata). Despite the fact the sound of fire. Proceedings of the Royal Society of London that the site 1 was an agricultural area, it seemed to be a B 269: 999–1003. suitable site for H. guttulatus. Site 3 was dominated by Grafe, T.U., Stewart, M.M., Lampert K.P., Rödel M.-O. (2011): floating aquatic plants (Nymphaea spp.) and only held a Putting toe clipping into perspective: a viable method for small population of H. guttulatus. marking anurans. Journal of Herpetology 45: 28–35. Whereas our study could add to the knowledge of Henzi, S.P., Dyson, M.L., Piper, S.E., Passmore, N.E., Bishop, the reproductive behaviour of H. guttulatus, further P. (1995): Chorus attendance by male and female painted reed frogs (Hyperolius marmoratus): environmental factors and questions remain open. It would be of particular interest selective pressures. Functional Ecology 9: 485–491. to further examine the significance of the different Kouamé, D., Adou, Y.C.Y., Kouassi, K.E., N’guessan, K.E., male colour morphs, and potential mate choice in H. Akoi, K. (2008): Preliminary floristic inventory and diversity guttulatus, including e.g. the influence of colour and/or in Azagny National Park (Côte d’Ivoire). European Journal of 5 duration of male presence at the breeding sites. Scientific Research 23: 537–547. Kouamé, D., Adou, Y.C.Y., Nandjui, A., N’guessan, K.E. (2010): Acknowledgements. We are grateful to the “Office Ivoirien Le rôle de l’éléphant dans la germination des graines Irvingia des Parcs et Réserves” and the “Direction des Eaux et Forêts gabonensis (germination Irvingiaceae), Balanites wilsoniana de Côte d’Ivoire” for the access permit to Azagny National (Balanitaceae), excelsa () et Park. The research permission was issued by the “Ministère Sacoglottis gabonensis (Humiriaceae) en forêt tropicale: cas du de l’Enseignement Supérieur et de la Recherche Scientifique”, Parc National d’Azagny en Côte d’Ivoire. International Journal Republic of Ivory Coast. of Biological and Chemical Sciences 4: 1442–1454. Lampert, K.P., Linsenmair, K.E. (2002): Alternative life cycle References strategies in the West African reed frog : the answer to an unpredictable environment? Oecologia 130: Bell, R.C., Zamudio, K.R. (2012): Sexual dichromatism in frogs: 364–372. natural selection and unexpected diversity. Proceedings of the Lauginie, F. (2007): Conservation de la nature et aires protégées en Royal Society B 279: 4687–4693. Côte d’Ivoire. Abidjan, Editions CEDA/NEI et Afrique Nature, Bishop, P.J., Jennions, M.D., Passmore, N.I. (1995): Chorus size 668 pp. Contributions to reproductive biology and behaviour of Hyperolius guttulatus 641

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Appendix List of frog voucher specimens from the Azagny National Park. Given are field (MK) and collection numbers, collection site, sex and collection date.

Hyperoliidae: Hyperolius guttulatus: MK001 (Site 1, phJ♂, 18 Apr. 2014), MK002 (Site 1, phJ♂, 18 Apr. 2014), MK003 (Site 1, phJ♂, 18 Apr. 2014), MK004 (Site 1, ♀, 18 Apr. 2014), MK005 (Site 1, ♀, 18 Apr. 2014), MK006 (Site 1, phF♂ 19 Apr. 2014), MK007 (Site 1, phF♂, 20 Apr. 2014), MK008 (Site 1, phJ♂, 21 Apr. 2014), MK009 (Site 1, phJ♂, 21 Apr. 2014), MK010 (Site 2, phF♂, 22 Apr. 2014), MK011 (Site 2, phF♂, 23 Apr. 2014), MK012 (Site 2, ♀, 25 Apr. 2014), MK013 (Site 2, ♀, 26 Apr. 2014), MK014 (Site 3, phF♂, 14 Oct. 2014), MK015 (Site 3, ♀, 14 Oct. 2014).

Accepted by Christoph Liedtke