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The understanding of feeding habits is important for anurans in general, both from an ecological and a phylogenetic perspective. For diurnal poison frogs belonging to the Dendrobatidae family, diet aspects play a crucial role in their defense and survival. Herein, we investigated feeding habits, foraging behaviour, and overall effects of habitat, sex, and body size on the diet of individuals of Ameerega braccata, a poorly known dendrobatid species. Specimens were observed and collected in the type-locality, Chapada dos Guimarães, and in the neighbouring municipality of Cuiabá, both in the State of Mato Grosso, Midwestern Brazil. The most important prey categories for A. braccata were Formicidae, Isoptera, and Acari, whose representatives were caught during active foraging. Individuals from Chapada dos Guimarães population consumed more Acari but fewer Isoptera than individuals from Cuiabá. Despite this, niche breadth values were narrow and similar for the two populations. Individuals from two distinct habitats (campo sujo and cerrado stricto sensu) showed differences in their diet, probably as an effect of differential prey availability. Females consumed more Isoptera than males. The number of prey categories used as food was not influenced by the variation of body size of the target species. However, the abundance and the volume of consumed Acari were statistically correlated with body size. The main results suggest that Ameerega braccata has a narrow niche breadth, as well as a specialised diet in ants, termites, and mites, which reinforces the hypotheses of close association between Acari consumption and the presence of skin toxic alkaloids, already found in other species of Dendrobatidae. Although differences in prey consumption between sexes are uncommon among poisonous frogs, differences in the diet composition between age classes, which probably reduce intraspecific competition, are frequently reported.
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Diet of Ameerega braccata (Steindachner, 1864)
(Anura: Dendrobatidae) from Chapada dos Guimarães
and Cuiabá, Mato Grosso State, Brazil
Forti, LR.a,d*, Tissiani, ASO.a, Mott, T.a,b and Strüssmann, C.a,c
aPrograma de Pós-graduação em Ecologia e Conservação da Biodiversidade, Instituto de Biociências,
Universidade Federal de Mato Grosso – UFMT, Av. Fernando Corrêa da Costa, 2367,
Bairro Boa Esperança, CEP 78060-900, CCBS-II, Boa Esperança, Cuiabá, Mato Grosso, Brazil
bDepartamento de Biologia e Zoologia, Universidade Federal de Mato Grosso – UFMT,
Av. Fernando Corrêa da Costa, 2367, Bairro Boa Esperança, CEP 78060-900, Cuiabá, Mato Grosso, Brazil
cDepartamento de Ciências Básicas e Produção Animal, Faculdade de Agronomia e Medicina Veterinária e Zootecnia,
Universidade Federal de Mato Grosso – UFMT, Av. Fernando Corrêa da Costa, 2367,
Bairro Boa Esperança, CEP 78060-900, Cuiabá, Mato Grosso, Brazil
dPrograma Interunidades de Pós-graduação em Ecologia Aplicada, Escola Superior de Agricultura “Luiz de Queiroz”,
Universidade de São Paulo – USP, Av. Pádua Dias, 11, CP 9, CEP 13418-900, Piracicaba, SP, Brazil
*e-mail: lucas_forti@yahoo.com.br
Received December 2, 2009 – Accepted February 4, 2010 – Distributed February 28, 2011
(With 3 figures)
Abstract
The understanding of feeding habits is important for anurans in general, both from an ecological and a phylogenetic
perspective. For diurnal poison frogs belonging to the Dendrobatidae family, diet aspects play a crucial role in their
defense and survival. Herein, we investigated feeding habits, foraging behaviour, and overall effects of habitat, sex,
and body size on the diet of individuals of Ameerega braccata, a poorly known dendrobatid species. Specimens were
observed and collected in the type-locality, Chapada dos Guimarães, and in the neighbouring municipality of Cuiabá,
both in the State of Mato Grosso, Midwestern Brazil. The most important prey categories for A. braccata were
Formicidae, Isoptera, and Acari, whose representatives were caught during active foraging. Individuals from Chapada
dos Guimarães population consumed more Acari but fewer Isoptera than individuals from Cuiabá. Despite this, niche
breadth values were narrow and similar for the two populations. Individuals from two distinct habitats (campo sujo and
cerrado stricto sensu) showed differences in their diet, probably as an effect of differential prey availability. Females
consumed more Isoptera than males. The number of prey categories used as food was not influenced by the variation of
body size of the target species. However, the abundance and the volume of consumed Acari were statistically correlated
with body size. The main results suggest that Ameerega braccata has a narrow niche breadth, as well as a specialised
diet in ants, termites, and mites, which reinforces the hypotheses of close association between Acari consumption and
the presence of skin toxic alkaloids, already found in other species of Dendrobatidae. Although differences in prey
consumption between sexes are uncommon among poisonous frogs, differences in the diet composition between age
classes, which probably reduce intraspecific competition, are frequently reported.
Keywords: Ameerega braccata, niche breadth, Anura, Dendrobatidae, diet.
Dieta de Ameerega braccata (Steindachner, 1864) (Anura: Dendrobatidae)
de Chapada dos Guimarães e Cuiabá, Estado do Mato Grosso, Brasil
Resumo
A compreensão de hábitos alimentares é de relevância ecológica e filogenética para espécies de anuros em geral. Para
sapos diurnos da família Dendrobatidae, aspectos da dieta exercem papel crucial na defesa e, consequentemente, na
sobrevivência. No presente trabalho, investigamos a composição alimentar, comportamento de obtenção de presas, o
efeito do tipo de habitat, sexo e tamanho do corpo sobre a dieta de indivíduos de Ameerega braccata, uma espécie da
família Dendrobatidae ainda pouco conhecida. Os espécimes foram observados e coletados na localidade tipo, Chapada
dos Guimarães e em Cuiabá, Mato Grosso, centro-oeste do Brasil. As categorias de presas mais importantes nos
estômagos de A. braccata foram Formicidae, Isoptera e Acari, cujos representantes foram capturados por forrageamento
ativo. Os indivíduos da população de Chapada dos Guimarães consumiram mais Acari e menos Isoptera do que os
indivíduos da população de Cuiabá, mas os valores de amplitude de nicho foram estreitos e similares entre as duas
Braz. J. Biol., 2011, vol. 71, no. 1, p. 189-196 189
Forti, LR. et al.
Cuiabá, Midwestern Brazil? 2) Is this a specialised or a
generalised species regarding prey selection? 3) What
feeding strategies are employed in prey capture? 4) Are
there any effects of habitat type, sex, and body size on the
diet of A. braccata?
2. Material and Methods
2.1. Study area
The field work was conducted in two localities, only
9 km away from one another, but situated in two distinct
municipalities from the State of Mato Grosso, Midwestern
Brazil: Chapada dos Guimarães (approximately 15° 24’ S
and 55° 50’ W; 650 m a.s.l.) - the type-locality of the species,
and Cuiabá (approximately 15° 20’ S and 55° 53’ W;
250 m a.s.l.). Data collection occurred in the wet season,
from October 2007 to March 2008. Forty-four individuals
were found in two open physiognomies of the Cerrado
ecosystem (Figure 1): campo sujo, mainly composed of
grasses and sparse tall shrubs, and cerrado stricto sensu,
where small trees are sparsely present in the landscape. For
a more detailed description of the sampled physiognomies
see Conceição (2000).
The annual mean precipitation in Chapada dos Guimarães
ranges from 1,800 to 2,000 mm, and the mean temperature,
from 22.8 °C in July, to 27.2 °C, in October (Pinto and
Hay, 2005). In Cuiabá, the climate is nearly the same as
in Chapada, semi-humid (Aw in Köppen’s classification,
see Nimer, 1979), with two well defined seasons: a
cold and dry season (from April to September), and a
warm and wet season, from October to March each year
(Diniz et al., 2008), with a mean temperature of 25 °C
(Schreiner et al., 2009).
2.2. Data collection
Feeding strategies, location, and the period of feeding
of individuals of Ameerega braccata were observed during
100 hours by using focal animal method (Altmann, 1974).
Dietary items from the stomachs of 44 individuals (28
from Cuiabá collected in cerrado stricto sensu and 16 from
Chapada dos Guimarães, of with 14 collected in cerrado
campo sujo and other two, in cerrado stricto sensu) were
removed and analysed in the Herpetological Laboratory
at Universidade Federal do Mato Grosso, Cuiabá, Brazil.
populações. Indivíduos de diferentes tipos de habitat (campo sujo e cerrado stricto sensu) apresentaram diferenças
na dieta, como um provável efeito da distinta disponibilidade de presas em cada um dos habitat. Fêmeas consomem
mais Isoptera do que os machos. A variação no tamanho do corpo não exerce efeito sobre o número de categorias de
presas consumidas. Abundância e volume de ácaros consumidos são significativamente relacionados com o tamanho
do corpo dos indivíduos. Os principais resultados sugerem que Ameerega braccata tem estreita amplitude de nicho e
dieta especializada em formigas, cupins e ácaros, corroborando a ideia de associação entre este último item e a presença
de alcaloides na pele de espécies da família Dendrobatidae. Poucos autores encontraram diferenças entre sexos no
consumo de presas por anuros. Diferenças na composição da dieta entre jovens e adultos, entretanto, são frequentes e
podem ser consideradas uma característica conservativa, que impede a competição intraespecífica entre classes etárias.
Palavras-chave: Ameerega braccata, largura de nicho, Anura, Dendrobatidae, dieta.
1. Introduction
Aspects of feeding habits of amphibians have been
intensively studied (e.g., Strüssmann et al., 1984; Lima and
Magnusson, 1998; Lima, 1998; Van Sluys and Rocha, 1998;
Van Sluys et al., 2001; Lima et al., 2002; Vaz-Silva et al.,
2005; Jordão-Nogueira et al., 2006; Siqueira et al., 2006;
Almeida-Gomes et al., 2007a,b), which is certainly
related to the outstanding trophic role played by these
organisms in many ecological systems. The majority of
amphibian species is considered generalist regarding diet,
and opportunistic regarding prey selection (Duellman and
Trueb, 1994; Teixeira and Coutinho, 2002; Santos et al.,
2004). Therefore, for the majority of species, the spectrum
of dietary items is wide, and reflects the availability of prey
items in the environment (Giaretta et al., 1998; Santos et al.,
2004). However, many other features may influence prey
consumption, such as foraging strategies (wide foraging
versus ambush predation), spatial and temporal variations,
sex, ontogeny, and body size (Strüssmann et al., 1984;
Biavati et al., 2004).
The Dendrobatidae family includes 169 recognised
species of mainly diurnal anurans distributed on the
Amazonian rain forest (Frost, 2009). These frogs are
poisonous, have specialised diets, mainly composed of
ants, termites, and mites (Toft, 1980; Caldwell, 1996;
Lima et al., 2002; Santos et al., 2003; Biavati et al.,
2004), and are species are characterised by their bright
colouration and potent skin toxins (Lötters et al., 2000).
In many species of dendrobatids, a close association has
been found between selected prey items and such skin
toxic substances, suggesting that they are sequestered from
diet (e.g., Dumbacher et al., 2004; Mortari et al., 2004;
Takada et al., 2005. See also Darst et al., 2005).
Ameerega braccata (Steindachner, 1864) is a colorful
dendrobatid distributed in the savannah-like Cerrado
ecosystem from Central and Midwestern Brazil, where
it is known from localities in the States of Mato Grosso,
Mato Grosso do Sul, and Goiás (Frost, 2009). A few
aspects of the natural history of this species have already
been addressed (Haddad and Martins, 1994; Forti et al.,
2010).
The present study aims to investigate some aspects of the
diet of A. braccata in its natural environment, specifically:
1)- What are the most important dietary items for Ameerega
braccata from Chapada dos Guimarães (type-locality) and
Braz. J. Biol., 2011, vol. 71, no. 1, p. 189-196
190
Diet of Ameerega braccata
The volume (in mm
3
) of each single prey item was
estimated by using the ellipsoid formula (V= 4/3 x ϖ x
W2/4 x L/2, where L = prey width, and C = prey length,
both measurements in mm, by using a digital caliper). A
fragmented prey was counted only when a corresponding
head was found. Width and length of fragmented prey
were estimated based on intact specimens of the same
kind of prey.
The importance index of each prey category was calculated
by means of the formula: I = (F%+N%+V%)/3.
To correct for sample size the number of prey categories
consumed by the two populations for sample size, a
rarefaction curve with 1000 aleatorizations was constructed
to each locality. The species richness of preys was computed
using the software EcoSim 7.0 (Gotelli and Entsminger,
2009).
Niche breadth (B) for each population was calculated
by using Levin’s measure (Krebs, 1998), expressed as
follows: B = 1/ pi
2,
where i is the resource category,
and p is the proportion of the resource category i. For the
standardisation of the obtained values between zero and
one, we employed the formula: B
A
= B – 1/ n – 1, where B
A
is the standardised niche breadth and n is the total number
of prey categories found in the stomachs (Krebs, 1998).
The abundance and volume of prey were log-transformed
and graphs were generated to evaluate if there were
differences in the diet composition between sexes in
A. braccata (valid just for Cuiabá population) and between
individuals occupying distinct habitats (campo sujo and
cerrado stricto sensu). To evaluate if body size affects the
variety of consumed prey, a linear regression was run,
using SVL as the explanatory variable and the number of
prey categories (taxa) as the response/dependent variable.
Regression analyses were also performed to evaluate
potential changes in the consumption of selected prey types
by frogs of distinct body sizes. This was done by plotting
SVL as the explanatory variable, and the abundance and
volume of the prey categories with higher importance
indexes as dependent variables.
3. Results
Males of Ameerega braccata foraged mainly after
the end of their calling session, both in the morning
(approximately between 7:30 AM and 9:00 AM) and
in the afternoon (approximately between 6:30 PM and
7:30 PM). Males were first sighted when still vocalizing,
perched in vegetation as described in Forti et al. (2010).
Just after having stopped to call, they jump to the ground
and begin to feed on the leaf litter. Seven females observed
while feeding also foraged on the leaf litter.
A total of 1,746 prey items, in 13 categories (12 orders
and one family), were found in the stomachs of Ameerega
braccata. We found a mean of 39.7 ± 40.6 items in
each stomach. Mean volume of prey by stomach was
105.52 ± 166.00 mm
3
. Most frequent prey items were
Formicidae, Acari (most of them belonging to the family
Oribatidae), Coleoptera, Isoptera, and Hymenoptera. When
All individuals were euthanised immediately after being
captured, by using standard protocols (Calleffo, 2002).
Dietary items were identified until order and family
level, whenever possible. Snout-vent length (SVL) of all
anurans was measured to the nearest 0.01 mm by using
a digital caliper (BTS®). The sex of individual frogs was
obtained either in the field (only for calling males) or in the
laboratory (by gonad inspection after dissection). Animals
were collected under IBAMA permit number 2075225,
and are presently housed in the Coleção Zoológica da
Universidade Federal de Mato Grosso (UFMT), Cuiabá,
Brazil, under the accession numbers UFMT 7695, 7696,
7698-7713, 7729-7735, 7749, 7751-7757, 7775-7785.
2.3. Data analyses
To describe the representativeness of the main prey
items consumed by individuals of A. braccata from the two
populations examined, each prey category was analysed
regarding its total frequency (F), relative frequency (F%),
total abundance (N), relative abundance (N%), total volume
(V), relative volume (V%), and importance index (I). We
also calculated the numeric mean (NM) and volumetric
mean (VM) of each prey category in each individual
stomach examined.
Figure 1. General aspect of two distinct habitats in which
individuals of the anuran Ameerega braccata were studied
in Midwestern Brazil: a) campo sujo; and b) cerrado stricto
sensu.
a
b
Braz. J. Biol., 2011, vol. 71, no. 1, p. 189-196 191
Forti, LR. et al.
considering all stomachs together, Formicidae was the most
abundant prey, followed by Isoptera and Acari. Regarding
the volume of the prey, Formicidae also surpassed other
prey types, being followed by Isoptera and Coleoptera.
The rarefaction estimative indicated that individuals
from Cuiabá consumed 12 types of prey categories and
those from Chapada dos Guimarães consumed 9 (Figure 2).
Nevertheless, Formicidae was the most consumed prey
category in the two populations. Individuals from Cuiabá
consumed more Isoptera than individuals from Chapada
dos Guimarães, which in turn consumed higher numbers
of Acari (Table 1 and 2).
Based in prey abundance in the stomachs of A. braccata,
niche breadth for the species was 1.729 (or 0.091, in
a standardised scale from zero to one) in Chapada dos
Guimarães, and 1.954 (or 0.080, in a standardised scale
from zero to one) in Cuiabá. When volumetric data of
prey were considered, niche breadth was 1.136 (or 0.017,
in a standardised scale from zero to one) in Chapada dos
Guimarães, and 1.946 (or 0.079, in a standardised scale
from zero to one), in Cuiabá.
Similarly to the comparison between populations, both
species composition and prey abundance slightly differed
in stomachs of individuals of A. braccata occupying
distinct habitats (Figure 3a, b). Formicidae was the main
prey category for individuals in both kinds of habitats.
However, individuals from cerrado stricto sensu consumed
more Isoptera than individuals from phytophysiognomies
of campo sujo, which in turn consumed more Acari.
Volumetrically, individuals living in cerrado stricto sensu
consumed higher volume of Isoptera, while individuals
Figure 2. Rarefaction curves of prey categories consumed
by individuals of Ameerega bracatta from two localities: a)
Chapada dos Guimarães; and b) Cuiabá. The black solid line
is the accumulation curve; broken line represents the aver-
age, calculated after 1000 aleatorizations, while grey lines
represent deviation from average.
a
b
Table 1. Diet composition of Ameerega braccata from Cuiabá, Mato Grosso state, Midwestern Brazil. (n) number of ana-
lysed specimens; (F) total frequency; (%F) relative frequency; (N) total abundance; (%N) relative abundance; (NM) numeric
mean; (V) total volume; (%V) relative volume; (VM) volumetric mean; (I) importance index.
Prey groups Frequency
(n = 28)
Abundance
(n = 28)
Volume
(n = 27)
Importance
F % F N % N NM V (mm3)% V VM I
Acari 11 39.29 39 4.69 1.39 ± 2.51 7.57 0.28 0.27 ± 0.80 14.75
Araneae 5 17.86 8 0.96 0.28 ± 0.81 11.19 0.41 0.40 ± 1.16 6.41
Chilopoda 2 7.14 2 0.24 0.07 ± 0.26 4.13 0.15 0.15 ± 0.47 2.51
Coleoptera (both
larvae and adults)
11 39.29 16 1.93 0.57 ± 0.88 58.86 2.14 2.10 ± 4.76 14.45
Collembola 3 10.71 10 1.20 0.35 ± 1.52 0.35 0.01 0.01 ± 0.06 3.98
Diplopoda 1 3.57 2 0.24 0.07 ± 0.37 x x x x
Diptera (both larvae
and adults)
4 14.29 4 0.48 0.14 ± 0.35 3.29 0.12 0.11 ± 0.37 4.96
Formicidae (both
larvae and adults)
26 92.86 571 68.71 20.40 ± 35.13 799.17 29.08 28.54 ± 48.74 63.55
Hemiptera 3 10.71 6 0.72 0.21 ± 0.78 2.77 0.10 0.10 ± 0.52 3.85
Hymenoptera* 6 21.43 8 0.96 0.28 ± 0.60 4.24 0.15 0.15 ± 0.55 7.52
Homoptera 3 10.71 4 0.48 0.14 ± 0.45 57.13 2.08 2.04 ± 6.41 4.42
Isoptera 16 57.14 159 19.13 5.67 ± 11.38 1799.06 65.46 64.25 ± 159.58 47.25
Thysanoptera 2 7.14 2 0.24 0.07 ± 0.26 0.59 0.02 0.02 ± 0.11 2.47
*Excepting Formicidae
Braz. J. Biol., 2011, vol. 71, no. 1, p. 189-196
192
Diet of Ameerega braccata
Table 2. Diet composition of Ameerega braccata from Chapada dos Guimarães, Mato Grosso State, Midwestern Brazil.
(n) number of analysed specimens; (F) total frequency; (%F) relative frequency; (N) total abundance; (%N) relative abun-
dance; (NM) numeric mean; (V) total volume; (%V) relative volume; (VM) volumetric mean; (I) importance index.
Prey groups Frequency
(n = 16)
Abundance
(n = 16)
Volume
(n = 15)
Importance
F % F N % N NM V (mm3)% V VM I
Acari 14 87.5 140 15.30 8.75 ± 12.31 7.79 0.463 0.55 ± 0.70 34.42
Araneae 5 31.25 5 0.55 0.31 ± 0.47 6.44 0.383 0.46 ± 1.21 10.73
Coleoptera (both
larvae and adults)
8 50 20 2.19 1.25 ± 1.52 60.99 3.623 4.35 ± 6.90 18.60
Collembola 3 18.75 4 0.44 0.25 ± 0.57 0.91 0.054 0.06 ± 0.20 6.41
Diptera (both larvae
and adults)
2 12.5 2 0.22 0.12 ± 0.34 7 0.416 0.5 ± 1.87 4.38
Formicidae (both
larvae and adults)
16 100 679 74.21 42.43 ± 38.52 1577.96 93.735 112.71 ± 117.43 89.31
Hymenoptera* 5 31.25 10 1.09 0.62 ± 1.08 9.63 0.572 0.68 ± 1.75 10.97
Homoptera 1 6.25 1 0.11 0.06 ± 0.25 0.1 0.006 0.01 ± 0.02 2.12
Isoptera 3 18.75 54 5.90 3.37 ± 12.45 12.6 0.748 0.90 ± 2.52 8.47
*Excepting Formicidae
in campo sujo consumed a higher volume of Formicidae
(Figure 3c, d).
Males and females differed regarding the abundance
of consumed prey (Figure 3e, f). Volumetrically, however,
stomachs of male frogs contained a higher volume of
Formicidae, thus differing from the females who consumed
a higher volume of Isoptera (Figure 3g, h).
The regression analysis between the number of prey
categories and body size of the frogs (SVL) was not
statistically significant (r
2
= 0.08, p > 0.05, F = 3.86,
N = 42).
Regression analysis between abundance of each prey
category and SVL (Table 3), and between the volume of
each prey category and SVL (Table 4) were only significant
for Acari.
4. Discussion
Considering the relative high frequency, high abundance,
and high volume of Formicidae among prey categories
consumed by A. braccata, this frog species can be regarded as
an ant specialist. Toft (1980) proposed some generalizations
on the feeding habits of amphibians and characterised
two guilds: 1) the ant specialists, which tend to be active
foragers, poisonous, and prey on many small items in a
feeding session, and 2) the non ant specialists, ambushing
and cryptic predators, which consume a few big prey
each day. The first guild typically includes many species
of the family Dendrobatidae (Taigen and Pough, 1983;
Caldwell, 1996; Lima, 1998). Active foraging behavior
leads to a longer exposition time outside shelter and to
an increased risk of predation. This may explain why
species employing this feeding strategy are usually more
toxic, more colorful, or even more cryptic than ambushing
species (Toft, 1980).
Toxic substances present in living organisms have two
possible origins: 1) they are synthesised by the organism
itself (endogenous route), or 2) they are aquired from
items in the diet (exogenous route) (Darst et al., 2005).
Results from experiments in which dendrobatids were
maintained in enclosures (genera Ameerega, Dendrobates,
Oophaga and others) suggest and corroborate the idea
that toxic alkaloids are sequestered from some specific
prey (Daly et al., 1994). Although there is no biosynthetic
evidence in support to this hypothesis (Takada et al., 2005),
the specialised diet in ants recorded for many dendrobatids
has been considered associated both with the presence of
skin alkaloids and with aposematic coloration, as defensive
strategies (Caldwell, 1996; Darst et al., 2005).
Acari (mainly of the family Oribatidae, which according
Takada et al., 2005, may also contain alkaloids that can be
sequestered by predators) were also frequently found in
the stomachs of individuals of A. braccata. Volumetricaly,
however, Isoptera was the most relevant prey category.
Biavati et al. (2004) argumented that termites (Isoptera)
are energetically worthwhile, as they contain fewer
amounts of sclerotised material and higher levels of
carbohidrates than ants. This may explain why females
of A. braccata consumed a higher volume of Isoptera
than males, due to the higher energetic demands during
reproduction. Nevertheless, Biavati et al. (2004) did not
find any difference in the composition of the diet of males
and females of A. flavopicta.
Formicidae has been the main prey of Ameerega bracatta
at both study sites (Chapada dos Guimarães and Cuiabá),
however, there was a relevant difference in composition of
prey between these two populations. In the present study,
diet comparisons between populations can be considered
quite equivalent to comparisons between habitats, due to
the prevalence of cerrado stricto sensu in Cuiabá, while
Braz. J. Biol., 2011, vol. 71, no. 1, p. 189-196 193
Forti, LR. et al.
Figure 3. Log-transformed prey abundance in the stomachs of 44 individuals of Ameerega braccata captured in a) cerrado
stricto sensu (N = 30) and b) campo sujo (N = 14); Log-transformed prey volume in 42 individuals of A. braccata from
c) cerrado stricto sensu (N = 30) and d) campo sujo (N = 12); Log-transformed prey abundance from e) males (N = 29)
and f) females (N = 8) of A. braccata; Log-transformed prey volume from g) males (N = 27) and (H) females (N = 8) of
A. braccata. Abbreviations for prey categories: Acari (AC), Araneae (AR), Coleoptera (CO), Collembola (CL), Diptera (DI),
Formicidae (FO), Hemiptera (HE), Homoptera (HO), Hymenoptera (HY), Isoptera (IS).
ab
cd
ef
g
h
individuals from Chapada dos Guimarães were collected
mainly in cerrado campo sujo.
Differences in the abundance and volume of prey
consumed by individuals of A. braccata living in distinct
habitats may be associated with the structural peculiarities
of each surveyed site, such as soil type, microclimate,
vegetation structure, which possibly influence the local
distribution and availability of prey. In Cerrado environments
of Central Brazil, Biavati et al. (2004) recorded Isoptera
as the main food for A. flavopicta, and also as the most
abundant prey items available in those habitats where the
frogs were obtained.
Niche breadth values found for Ameerega braccata
populations were relatively low and similar to values
reported for other dendrobatid species, such as A. bilinguis,
A. flavopicta, A. hahneli, A. parvula, A. petersi, A. picta,
A. trivittata, Dendrobates auratus, Oophaga pumilio and
Ranitomeya ventrimaculata (Biavati et al., 2004; Darst et al.,
2005; Toft, 1980). All these species consume a small
variety of prey, being usually specialised in consuming a
Braz. J. Biol., 2011, vol. 71, no. 1, p. 189-196
194
Diet of Ameerega braccata
competition for feeding resources between froglets and
adult individuals (Lima, 1998). However, additional studies
must be conducted to assess whether ontogenetic changes
in the diet are usual for anurans.
Acknowledgements — We thank Luiz Antônio Solino, Tainá
Dorado and Derek Ito for their help in the fieldwork, and
Taran Grant and Domingos de Jesus Rodrigues for suggestions
and critical reading of an early version of the manuscript. We
thank CAPES-PRODOC for financial support and João Bosco
Cajueiro for providing logistic support for this work. We thank
Jenifer Dunlap for English editting.
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Formicidae 42.63 0.04 0.13 >0.05
Hymenoptera 0.27 0.004 0.01 >0.05
Isoptera –15.07 0.12 0.37 >0.05
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... Nevertheless, there is scarce information about the aspects of natural history for Ameerega species (e.g. Forti et al. 2011;Lima & Eterovick 2013;Summers & Tumulty 2014). The Pantanal of Mato Grosso do Sul, Brazil is surrounded by plateaus covered by Cerrado senso strictu, Cerradão, and semi-deciduous forests, which are threatened by land-use conversion, such as agriculture and cattle ranching (Scariot et al. 2005;Alho 2008). ...
... Our results showed ants as the most frequent prey category, with the greatest total volume of stomach content and the highest index of relative importance, ingested by A. berohoka and A. picta in the plateaus surrounding the Pantanal of Mato Grosso do Sul. Similar results have been documented for Ameerega picta (Ramon et al. 2010;Landgref-Filho et al. 2019) and other populations of Ameerega from different biomes (Caldwell 1996;Forti et al. 2011;Lima & Eterovick 2013;Luiz et al. 2015). ...
... Coleoptera is the largest order of insects in the world and is present in most environments in Brazil (Rafael et al. 2012), presenting a high availability for consumption, and Isoptera, such as termites, are energetically valuable because they contain less sclerotized material and a higher carbohydrate content than ants (Biavati et al. 2004). Coleoptera, Isoptera, and other registered orders such as Diptera, Acari, and Araneae were also representative prey categories for other populations of Ameerega from different biomes (Caldwell 1996;Forti et al. 2011;Lima & Eterovick 2013;Luiz et al. 2015). Such orders and Formicidae are abundant in the litter (Sakchoowong et al. 2008), where both of the Ameerega species studied here usually forage, which could explain the high contribution of these prey categories to the diet of A. berohooka and A. picta. ...
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Santana (2020): Diet and morphometry of two poison frog species (Anura, Dendrobatidae) from the plateaus surrounding the Pantanal of Mato Grosso do Sul state, Brazil, Studies on Neotropical Fauna and Environment, ABSTRACT The plateaus surrounding the Pantanal in Mato Grosso do Sul are highly threatened by land-use conversion and are home to Ameerega berohoka and Ameerega picta, two species of poison frogs renowned for their aposematic coloration and toxic skin. The species have diurnal and terrestrial habitats and are often observed among dead tree branches, leaf litter or under rocks. Herein, we investigated the diet and sexual dimorphism of body size in A. berohoka and A. picta, aiming to increase our understanding of the natural history of both species. We collected A. berohoka specimens from the Bonito municipality and A. picta from the Rio Negro Municipality and obtained 1,600 prey items organized into 12 categories. We found that formicid insects had the highest index of relative importance and were the most frequent prey category for both species. Despite prey items such as Acari and Isoptera being present in the diet of these species, the niche breadth of these species was low. We found no evidence of sexual dimorphism in body size or body shape for A. berohoka and A. picta. Based on our findings, we conclude that both species are ant specialists, as proposed for other Ameerega species. ARTICLE HISTORY
... Understanding trophic relationships between anurans is essential to clarify the role of these animals in nature (Forti et al. 2011), especially in complex food webs. Amphibians are opportunistic predators feeding on a large number of invertebrates and are preyed upon by vertebrates that rarely use arthropods as dietary items (Wilbur & Fauth 1990;Sheppard & Harwood 2005;Brose et al. 2006). ...
... Considering other Ameerega species occurring in the Cerrado, A. braccata presented higher prey richness than observed for A. berohoka (39.70 ± 46.60 items by stomach, Forti et al. 2011), and ingested a larger number of ants, Acari, Coleoptera, Isoptera, and Hymenoptera, with ants, termites, and beetles the most voluminous ingested items. Ameerega flavopicta also ingested more preys (13.04 ± 17.51, Biavati et al. 2004) than A. berohoka, although the diet of A. flavopicta can vary according to habitat. ...
... However, the consumption of these preys depends on their density and distribution in the environment, and differences in ingestion rates can occur throughout the year (Saporito et al. 2007b;Bull & Hayes 2009;Moskowitz et al. 2018). Although Ameerega flavopicta ingested fewer ants than related species occurring in the Amazon (Biavati et al. 2004;Lima & Eterovick 2013), ants were relevant in the diet of other related species in the Cerrado biome (Forti et al. 2011;Landgref-Filho et al. 2019;present study). Interestingly, social insects, in general, are relevant prey even for Ameerega species occurring in the Amazon (Luiz et al. 2015), and diverse strategies of alkaloid capturing and evolution of skin toxicity are expected to occur within different lineages in the Neotropics (see Darst et al. 2005), including circumstantial sequestration from termites or other arthropods. ...
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... It is likely that the prey items consumed by members of Andinobates is determined by their mouth dimensions and the availability of prey items in the microhabitat (Toft 1995;Caldwell 1996;Vitt and Caldwell 2014). However, the predominance of Acari, Hymenoptera and Coleoptera that we recorded for A. daleswansoni also has been recorded in the diet of other poison frogs with similar or larger mouth dimensions (Forti et al. 2011;Arce Domínguez and Rengifo Mosquera 2013;Osorio-Domínguez et al. 2015;Pacheco et al. 2020). Acari, Hymenoptera and Coleoptera in the diet of poison frogs is associated to the sequestration of chemical compounds used against predators (Daly et al. 2000;Santos et al. 2003;Darst et al. 2005;Saporito et al. 2012;Tarvin et al. 2017). ...
... Territorial behaviour in poison frogs have been correlated to the occupation of resources such as bromeliads and prey items (Summers and McKeon 2004;Erich 2013;Ringler et al. 2013;Poelman et al. 2013;Vargas-Salinas and Amézquita 2013b). Bromeliads are essential for the reproduction of many poison frogs (Summers and McKeon 2004) while specific food items determine chemical defences and warming colouration of individuals (Donnelly 1991;Saporito et al. 2010;Forti et al. 2011). However, we did not quantified microhabitat features for testing which kind of resources are promoting agonistic behaviours in A. daleswansoni, but it is expected to be similar to those in others poison frogs. ...
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... 1). A small variety of prey and high abundance of Formicidae have been found in the diet of other populations of A. picta (Toft 1980;Ramon et al. 2010) and congeneric species, such as A. bilinguis, A. braccata, A. flavopicta, A. hahneli, A. parvula, A. petersi and A. trivitatta (Toft 1980;Biavati et al. 2004;Darst et al. 2005;Forti et al. 2011;Luiz et al. 2015). The sequester of chemical defenses from dietary sources is an important adaptation to the anti-predator defense of dendrobatid frogs, as their diurnal habits result in greater exposure to predators (e.g., Luiz et al. 2015). ...
... Although Ameerega picta exhibits sexual dimorphism in body size (Uetanabaro et al. 2008), we did not find any significant difference between sexes regarding numeric percentages per prey category. Differences in diet composition between males and females are reported for A. braccata and A. trivitatta (Forti et al. 2011;Luiz et al. 2015), which may be related to behavioral differences that enable the partitioning of feeding resources between sexes. ...
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We provide data on the diet composition of Ameerega picta from the region of Serra da Bodoquena in the state of Mato Grosso do Sul, central Brazil. We also provide a summary of dietary studies on species of the genus Ameerega.
... The size of the predator is known to be an influential factor for anuran diets, as larger anurans consume a greater number of and larger prey (Sugai et al. 2012, Teles et al. 2018. Nevertheless, predator size is also a factor that selects and limits the prey that the predator can ingest, which may result in diets specialized in certain resources (Toft 1980, Forti et al. 2011, Silva et al. 2019). According to Rodrigues et al. (2005), S. fuscovarius males are significantly smaller than females, however, no differences in relation to sex were found herein, but between males and juveniles there was a difference. ...
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... While studies of feeding habits of anurans have been increasing in number (e.g., Ortega et al. 2005, Forti et al. 2011, Solé et al. 2019, the relationship between frogs and their preys is still little known. Descriptive studies are fundamental to reveal complex predator-prey interactions and to determine the role of anurans in ecosystems (Hocking & Babbitt 2014). ...
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... Some studies have already shown that prey availability can change seasonally, and these changes should be considered as a determinant factor for anuran diets (Cogălniceanu et al., 2001) as prey availability is intrinsically related to the trophic ecology of anurans (Kikuchi and Ueida, 1998;Ott and Carvalho, 2001;López et al., 2009). Amphibians are considered opportunistic and generalist predators (Vaz-Silva et al., 2005;Toledo et al., 2007;Neves et al., 2014), but some families (e.g., Microhylidae and Dendrobatidae) have specialized diets, feeding mostly on ants (Hymenoptera: Formicidae) and termites (Isoptera) (Attademo et al., 2007;Berazategui et al., 2007;Santana and Juncá, 2007;Forti et al., 2011). ...
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... In addition, we found that the importance of ants in the diet of P. luteolus was independent of environment, which is further indicative of diet specialization, similar to other frog species. For example, ants also represented more than 50% of the diet of two other dendrobatid frogs (Ameerega flavopicta and A. braccata), which were thus classified as specialist predators with active foraging behavior (Biavatti et al., 2004;Forti et al., 2011). However, it is necessary to consider prey availability to determine whether the amount of ants consumed by P. luteolus was proportionate to the abundance of this prey in its environment. ...
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