DOI: 10.1111/eea.12797
The Amazonas-trap: a new method for sampling
plant-inhabiting arthropod communities in tropical
forest understory
Marta C. Lopes1,2 , Greg P.A. Lamarre3,4, Christopher Baraloto5, Paul V.A. Fine6,
Alberto Vincentini7 & Fabricio B. Baccaro8*
1
Programa de Pos-Graduacß~ao em Entomologia, Instituto Nacional de Pesquisas da Amaz^onia, Manaus Brasil, 2Instituto
Federal de Educacß~ao, Ci^encia e Tecnologia do Amazonas, Tabatinga Brasil, 3Institute of Entomology, Biology Centre, Czech
Academy of Science, Ceske Budejovice Czech Republic, 4INRA, UMR Ecologie des For^ets de Guyane, Kourou French Guiana,
5
International Center for Tropical Botany, Department of Biological Sciences, Miami FL, USA, 6Department of Integrative
Biology, University of California, Berkeley CA, USA, 7Coordenacß~ao de Biodiversidade, Instituto Nacional de Pesquisas da
Amaz^onia, Manaus Brasil, and 8Departamento de Biologia, Universidade Federal do Amazonas, Manaus Brasil
Accepted: 6 January 2019
Key words: inventory, sampling efficiency, sampling sufficiency, insect-plant interaction, sampling
technique, Protium saplings, Hymenoptera, Burseraceae, permanent plots, beating tray, manual
collection
Abstract
Methods to quantify plant-insect interactions in tropical forests may miss many important arthropods and can be time consuming and uneven in capture efficiency. We describe the Amazonas-trap,
a new method that rapidly envelops the target plant for sampling arthropods. We evaluated the efficiency of the Amazonas-trap by comparing it with two commonly used sampling methods to collect
arthropods from plants: the beating tray and manual collection. Samples were collected in 10 permanent plots, in the Ducke forest reserve, Manaus (Amazonas, Brazil). In each plot we sampled 18 plant
individuals of Protium sp. (Burseraceae): six by a beating tray, six by manual collection, and six using
the Amazonas-trap. All insects were identified to the family level and those belonging to the order
Hymenoptera were identified to the species and morphospecies level. The new method sampled
more insect families and more Hymenoptera species than tree beating and manual collection. Of the
75 total families collected, 20 were sampled exclusively by the Amazonas-trap, seven were only collected with a beating tray, and seven were sampled exclusively with manual collecting. A similar pattern was found for abundance: Amazonas-trap sampled more individuals, followed by the beating
tray and manual collection. Small and winged arthropods were more abundant in Amazonas-trap,
explaining the highest richness of Hymenoptera and insect families sampled with this method. The
new method sampled more spiders, wood-fungi feeders, sap suckers, omnivorous, parasitoids, and
insect predators than the other methods, but was equally effective in sampling leaf-feeders and ants.
Amazonas-trap was more time consuming in the field, but for all diversity parameters evaluated, the
new method showed better performance for collecting invertebrates on plants.
Introduction
Plants represent a primary resource and the base of complex interactive food web networks in terrestrial ecosystems. Herbivorous insects are the most abundant and
*Correspondence: Fabricio B. Baccaro, Departamento de Biologia,
Universidade Federal do Amazonas, Av. General Rodrigo Octavio,
6200, Coroado I Cep: 69080-900, Manaus, Brasil.
E-mail: baccaro@ufam.edu.br
534
diverse group of organisms generally found on vegetation
(Strong et al., 1984). Plants also harbor other important
arthropod functional groups, such as predators that use
plants as substrate to find their prey (Wise, 1993), decomposers that find shelter on plants (Santos et al., 2003), parasitoids of eggs and larvae (Fernandez & Sharkey, 2006),
and ants that nest in domatia or forage for food on
extrafloral nectaries (Oliveira & Brand~ao, 1991). Therefore, every plant individual supports assemblages of
arthropods from many trophic levels and represents an
© 2019 The Netherlands Entomological Society Entomologia Experimentalis et Applicata 167: 534–543, 2019
Unraveling understory plant-inhabiting arthropod fauna 535
appropriate ecological unit to investigate the occurrence,
diversity, and interactions among arthropod communities
(Farrell et al., 1992). A group of plants, in the same way,
can be used in ecological studies of coevolution or insectplant interaction, provided that appropriate collection
methods are applied.
The group of individuals that interact with a plant and
its associated fauna was initially called the ‘component
community’ (Root, 1973). However, this term is rarely
used in the recent literature, perhaps because of the difficulty of exhaustively sampling all invertebrates on a plant
at the same time. The primary challenge in sampling
arthropods on plants is that flying insects represent most
of the arthropod diversity associated with plants. Comprehensive methods for sampling flying insects in the forest
understory (e.g., Malaise traps and windowpane traps; see
Lamarre et al., 2012) are broadly used to relate the insect
community to the plant community in a given forest habitat (Lamarre et al., 2016). These methods produce broad
surveys of arthropod composition, but they cannot be performed at the level of an individual plant. Malaise-based
studies can therefore only indirectly link the arthropod
diversity with local habitats. In studies focusing on arthropod-plant interactions at the level of individual plants, a
method of active sampling (beating tray or manual collection) is more often employed (Basset & Novotny, 1999).
The beating tray technique allows fast and practical
sampling of invertebrates resting or feeding on plants and
can be considered as a selective method, as the insects falling from the vegetation are mainly wingless or less mobile
(Ozanne, 2005). Manual collection, although widely used,
does not sample the entire arthropod community present
on a plant. Small individuals or camouflaged/cryptic species may not be noticed by the collector, and more active
species have a high probability of escape. Consequently,
the sampled fauna depends partly on the ability and the
experience of the collector, which can create significant
bias that in turn can be challenging to standardize for comparison among sites and studies (Basset et al., 1997). Each
method produces its own result and no method is efficient
enough to exhaustively sample invertebrate communities
on a plant at a single time. Choosing the method of collection depends on the purpose of the study and on the targeted groups of arthropods.
In this study we describe the Amazonas-trap, a new
method for exhaustively collecting plant-inhabiting
arthropod assemblages in the tropical rainforest understory. This method, developed and designed by GPA
Lamarre, consists of a rapid and complete bagging of juvenile individuals, and differs from methods that involve
removing or enveloping branches or other plant parts
only (e.g., foliage bagging; Ozanne, 2005). To evaluate the
performance of the new method, we compared the structure and composition of the most abundant insect communities found on tropical plants, either sampled with the
Amazonas-trap, or with the most widely used sampling
methods: the beating tray and manual collection. We compared the method’s performance at both the plant and the
plot scale, which are the most common scales used in
insect-plant interaction studies. For a more comprehensive evaluation of the Amazonas-trap, we also compared
the time spent during survey among the three sampling
methods.
Materials and methods
Concept of the Amazonas-trap
The trap is made of white polyester (100%), a light and
resistant fabric measuring 3 m long and 3 m wide (Figure 1; see also the photographs in Figure S1). The two lateral sides of the fabric have a velcro strip along the entire
length of the trap. The bottom part of the fabric is folded
and sewn to form a hem of 3 cm wide, through which a
rope is inserted. The top part of the fabric also has a hem,
of 5 cm wide, through which a weldable PVC pipe of 2 cm
diameter and 1.5 m long is inserted. In one of the ends of
the pipe a three-way T-shaped connector (2 cm diameter)
is attached with bolt and nut. During installation, the other
end is inserted and manually screwed into the connector,
forming a circle with the collector around the plant, and
an aluminum tube (2 cm diameter, 2.5 m long) is also
attached to this connector. A 5-m rope with a loop knot at
the tip is inserted into a hem sewn 15 cm below the top of
the collecting cloth.
Figure 1 General structure of the Amazonas-trap: (1) velcro
strips, (2) bottom hem, (3) rope, (4) top hem, (5) PVC pipe, (6)
aluminum tube, (7) rope with loop knot, and (8) rope hem with
loop knot.
536 Lopes et al.
Installation and sampling procedure
The trap is designed to sample free-standing plants of 1–
3 m high that are at least 0.5 m from neighboring plants.
The trap is placed on the ground around the target plant
and the bottom part is tightly attached to its lowest branch
(Figure 2A). The weldable PVC pipe is also placed around
the plant with the two end-sections joined together forming a circle over the trap around the plant. The velcro is
tightly closed throughout its entire length, from the top to
the bottom, preventing escape by any arthropods. The end
of the rope is passed through the loop knot. Finally, the
aluminum tube is joined into the connector (Figure 2B).
As the installation of the trap may create some disturbance, chasing away insects, in this test the target plant was
left alone for 2 min before the trap was activated, allowing
the invertebrate fauna to return to the target plant. Meanwhile, other traps may be installed on other target plants.
Longer recovery time is probably more effective than the
2 min used here.
With the Amazonas-trap installed the activation is conducted as follows. First, the entire structure of the trap is
energetically pulled up by lifting the device upwards with
the help of the aluminum tube in order to completely
envelope the target plant. Simultaneously the rope is
pulled to close the top of the trap (Figure 2C). All invertebrates present on the plant are now trapped.
With all invertebrates trapped, the sampling procedure
can start. A small opening of the velcro allows the collector
to stick in her/his hand and vigorously shake the whole
plant usually by holding the most solid part of the trunk to
avoid physical damage (Figure S1D). All plant-inhabiting
arthropods fall into in the lower part of the trap, or are
resting in the fabric allowing very easy inspection by eye
and collection using an aspirator in the trap (Figure S1E,
F).
Testing Amazonas-trap performance
We compared the performance of the Amazonas trap with
two classical sampling methods, the beating tray and manually collecting, based on intensive field sampling at the
Ducke Forest Reserve (020 550 –03°010 S, 59°530 –
59°59.50 W), located in Manaus (Amazonas, Brazil).
Reserva Ducke is a 10 000-ha rainforest reserve covered by
typical ‘terra-firme’ forest on moderately rugged terrain
(elevation 50–120 m a.s.l.). The climate is tropical humid
with a mean ( SD) annual temperature of 26 3 °C
and mean annual precipitation of 2.2 m, which varies seasonally (Marques-Filho et al., 1981).
The surveys took place in 10 previously installed permanent plots, at least 1 km apart (Magnusson et al., 2013).
The plots were distributed over 10 km2 and cover the natural environmental variation found at Ducke: from the
clay poorly drained soils in the valleys to the clayed welldrained soils on the plateaus. These plots represent a gradient of local environmental conditions (Oliveira et al.,
2008). In each plot, we selected, marked, and identified 18
Protium sp. tree saplings (Burseraceae) of 1.5–2.5 m high.
Protium is a widespread and locally abundant tropical
Figure 2 Installation of the Amazonas-trap: (A) tying on the plant stem, (B) closing up of velcro and attaching the aluminum tube, and (C)
lifting and closing up by the collector.
Unraveling understory plant-inhabiting arthropod fauna 537
genus that occurs across the environmental gradient. We
focus on one plant lineage to minimize the influence of
variation of plant secondary compounds on insect assemblages (Salazar et al., 2018). The field work was carried out
in March and April 2016.
Sampling procedure
We sampled arthropod communities on focal plants using
(1) the classical beating tray, (2) manual collection, and
(3) the new Amazonas-trap. Each method was used on six
Protium plant individuals per plot. For the beating tray,
individual plants were agitated above a standard-size collection cloth (1 9 1 m) and the invertebrates were collected using an entomological aspirator. This process was
repeated until no more invertebrates fell on the cloth. For
the manual collection, the plants were carefully inspected
until all observed individuals were collected using entomological aspirator and forceps. This method was always
performed by the same collector. The Amazonas-trap collection was performed as previously described. The time
taken to sample the individual plants was measured for
each sampling method.
All insects collected were identified to family level. Insect
family level provides a practical diversity resolution, sufficient for detecting taxonomic and functional patterns of
assemblage composition in tropical forests (Lamarre et al.,
2016). We also sorted Hymenoptera (the most abundant
order sampled) further to species/morphospecies level
(Fernandez & Sharkey, 2006; Rafael et al., 2012; Baccaro
et al., 2015). The specimens belonging to the classes Arachnida, Malacostraca, Chilopoda, and Diplopoda were classified at the order level. Finally, to examine ecological
correlates of invertebrate assemblages, we grouped all
invertebrates sampled into guilds based on the feeding
habits and taxonomy of adults (Moran & Southwood,
1982; Basset & Arthington, 1992; Rafael et al., 2012;
Lamarre et al., 2016). The following guilds were erected:
ant, spider, insect predator, leaf-feeder, sap sucker, woodfungi feeder, omnivorous, and parasitoid.
Statistical analysis
Rarefaction curves were constructed for the number of
insect families or Hymenoptera species sampled by collection method per plant. Also, we constructed accumulation
curves for Hymenoptera species and insect families over the
total time of each sampling method. The 95% confidence
interval was estimated by the Mao-Tau method that does
not collapse around the mean at the highest values (Colwell
et al., 2004). This approach permits the comparison of rarefaction curves with higher shared sampling effort.
Subsequently, the number of insect families, Hymenoptera species, and the total number of individuals sampled
by each method per plot were compared by ANOVA. For
both matrices, number of insect families or Hymenoptera
species and the abundance of individuals per plot were the
dependent variables, and collection method was the independent variable. We used the same analytical scheme to
compare the guild abundance between methods. Comparisons among sampling methods were made with Tukey0 s
post hoc test.
The composition of the communities captured with
each collection method (families of all captured insects
and Hymenoptera species) were compared by multivariate
ANOVA by permutation (PERMANOVA), based on a dissimilarity matrix generated by the Bray–Curtis index
(Anderson, 2001). In all analyses, the sampling unit was
the plot, and the results were based on 999 permutations.
Simple ordering plots were created to present the composition and identity of the taxa (family and hymenopteran
species) sampled by each method. We also used a PERMANOVA to test possible bias toward plant species secondary
compounds. In this analysis, we compare the composition
of Protium species sampled by each method per plot, based
on Bray–Curtis distance. All analyses and graphs were
done in R v.3.4.4 (R Core Team, 2017). All data generated
during this study are included in Table S1.
Results
Overall, 21 Protium species were sampled. Even with the
high number of replicates (180), ca. 62% (13) of Protium
spp. were sampled by at least two of the sampling methods.
The remaining eight species were sampled by only a single
method. However, possible differences in arthropod composition related with plant species secondary defenses were
minimized given that the number of unique Protium species sampled were quite similar among sampling methods:
beating tray (3), manual collection (2), and Amazonastrap (3). In addition, the Protium assemblage composition
per plot was similar between sampling methods (PERMANOVA: F2,27 = 0.478, P = 0.96).
We collected in total 1 423 arthropod specimens among
the four main classes: Hexapoda (n = 1 039), Arachnida
(365), Diplopoda (14), and Malacostraca (5). Hexapoda
was the most abundant and species-rich group collected in
the understory of Amazonian tropical forests, representing
a total of 11 orders and 75 families. The most abundant
order was Hymenoptera (390 individuals), mostly composed of Formicidae (349 individuals), followed by
Collembola (272 individuals) and Coleoptera (175 individuals).
The Amazonas-trap sampled on average ( range) ca.
8 4 families more than beating tray and manual
collection per plot (ANOVA: F2,27 = 28.2, P<0.001). For
538 Lopes et al.
Formicidae, whereas of the 32 species sampled with the
beating tray, 26 were Formicidae. For the Amazonas-trap
60 species of Hymenoptera were collected, including 40
Formicidae species (Figure 5).
The Amazonas-trap sampled more spiders (ANOVA:
F2,27 = 30.11), wood-fungi feeders (F2,27 = 10.83), sap
suckers (F2,27 = 13.62), omnivorous (F2,27 = 13.99, all
P<0.001), parasitoids (F2,27 = 6.79, P = 0.004), and insect
predators (F2,27 = 17.38, P<0.001) than the other methods
(Figure 6). However, the number of ants (ANOVA:
F2,27 = 2.08, P = 0.15) and leaf feeders (F2,27 = 2.19,
P = 0.14) were similar among the three sampling methods. The manual collection sampled fewer individuals for
all guilds, except for leaf-feeders (Figure 6).
The Amazonas-trap was more time consuming in the
field, taking ca. 39 longer to sample the same number of
plants (Figure 7). On average, 11.4 arthropods were sampled per min using the beating tray, 8.3 per min using the
Amazonas-trap, and 4.1 per min with manual collection.
Although manual sampling collects hymenopteran species
faster, the three methods accumulate practically the same
number of insect families per unit of time (Figure 7).
Discussion
We described the Amazonas-trap, a new collection
method able to comprehensively sample the arthropod
community associated with plants. We also compared the
No. insect families
No. Hymenoptera species
Hymenoptera, the Amazonas-trap sampled on average ca.
4 2 more species compared with other methods per
plot (ANOVA: F2,27 = 10.47, P<0.001), whereas the beating tray and manual collection sampled a similar number
of Hymenoptera species per plot (Tukey’s test: P = 0.26).
At site and individual plant scales, the Amazonas-trap
sampled more families and Hymenoptera species than the
other two sampling methods (Figure 3).
This pattern was even stronger when considering insect
abundance. The Amazonas-trap sampled more individuals
per plot than the other two methods together (ANOVA:
F2,27 = 14.08, P<0.001). The number of insects sampled
(abundance) per plot was similar between the beating tray
and manual collecting (Tukey’s test: P = 0.19). The Amazonas-trap sampled 617 individuals, followed by the beating tray with 295 individuals, and manual collection with
127 individuals sampled.
The composition of the sampled families differed
among the three collection methods (PERMANOVA:
F2,27 = 3.74, P = 0.001). Of the total of 75 families collected, 20 were sampled exclusively when using the Amazonas-trap, seven were only collected with beating tray and
seven with manually collecting (Figure 4). However, there
was no difference in the composition of the sampled
Hymenoptera species among the collection methods
(PERMANOVA: F2,27 = 1.01, P = 0.41). Formicidae was
the most representative family in all methods. Of the 27
species of Hymenoptera manually collected, 24 were
No. plants sampled
No. plants sampled
Figure 3 Rarefaction curves for Hymenoptera species and insect families sampled with Amazonas-trap, beating tray, and manual
collection. The continuous lines represent accumulation and the polygon areas represent 95% confidence intervals. [Colour figure can be
viewed at wileyonlinelibrary.com]
Unraveling understory plant-inhabiting arthropod fauna 539
Insect families presence/absence
Rediviidae
Pyralidae
Paragryllidae
Megalopodidae
Lycidae
Ichneumonidae
Buprestidae
Anthicidae
Archipsocidae
Acrididae
Tettigonidae
Sphingidae
Scutelleridae
Sciaridae
Ptylodactilidae
Katiannidae
Histeridae
Frigitidae
Formicidae
Diapriidae
Curculionidae
Culicidae
Cicadidae
Chaeteessidae
Calliphoridae
Caeciliusidae
Bourlettiellidae
Blattelidae
Agaonidae
Chrysomelidae
Chironomidae
Reduviidae
Entomobryidae
Elateridae
Dicyrtomidae
Cantharidae
Brentidae
Cicadelidae
Tipulidae
Scarabaeidae
Phoridae
Nitidulidae
Heteromuridae
Eulophidae
Dictyopharidae
Ceratopogonidae
Cecidomyiidae
Staphylinidae
Lepidocyrtidae
Isotomidae
Imaturo
Dolichopodidae
Blaberidae
Braconidae
Schizopteridae
Mogoplistidae
Hybotidae
Sminthuridae
Platygastridae
Trigonidiidae
Tridactylidae
Thripidae
Thespidae
Psychodidae
Phalangopsidae
Neanuridae
Mymaridae
Meinertellidae
Lauxaniidae
Lachesilidae
Gryllidae
Figitidae
Eumastacidae
Eulophidae
Endomychidae
Derbidae
Delphacidae
Cleridae
Ceraphronidae
Carabidae
Brachystomellidae
Figure 4 Distribution of insect families
sampled with the three collection methods
on Protium saplings. The columns
represent the plots. The 10 columns on the
left (red bars) represent the Amazonas
trap, the 10 columns in the middle (blue
bars) the beating tray, and the 10 columns
on the right (green bars) the manual
collection. [Colour figure can be viewed at
wileyonlinelibrary.com]
Amazonas-trap performance with that of two other often
used sampling methods and found that our new method
proved to be better than the methods traditionally used for
most parameters tested. The new Amazonas-trap collected
more species of Hymenoptera, more families of insects,
and more individuals from most guilds than the widely
used tree beating and manual collection. Although somewhat more time consuming, the Amazonas-trap sampled
similar numbers of individuals and species per unit of time
compared with the other two methods. Overall, the Amazonas-trap provided a more accurate and exhaustive picture of the plant-inhabiting insect assemblages in this
lowland Amazonian rainforest.
The entomological beating tray, a widely used method
for insect sampling on plants (Ozanne, 2005), collected
nearly half of the species of hymenopterans and ca. 70% of
the insect families sampled by the Amazonas-trap. It is
likely that during the physical disturbance of the plant by
the beating tray, agile specimens escape, reducing efficiency. Winged insects and jumpers are particularly difficult to be sampled when using the beating tray. Entirely
enclosing the plant allows the collection of winged and
Ordered plots by sampling method
fast-moving insects, explaining the overall greater abundance and richness of the insect families and in particular
of Hymenoptera species sampled by the Amazonas-trap.
Very small insects can also be sub-sampled by beating
tray or manual sampling. For instance, manual collection
yielded the smallest number of individuals, species, and
families sampled, which is probably related to the difficulty
of capturing agile, cryptic, or very small specimens directly
on the plant. However, entirely enclosing the plant allows
the collection of very small or cryptic individuals, even
without seeing them in the field. That happens because all
the fine plant material that accumulates inside the trap,
together with the invertebrates, can be sampled with an
insect aspirator and then sorted under a stereomicroscope.
The families Mymaridae (Hymenoptera) and Thripidae
(Thysanoptera) are examples of small insects that are relatively difficult to observe and that were exclusively sampled with Amazonas-trap.
The composition of Hymenoptera species in all three
methods was dominated by ants, which is one of the most
abundant groups in tropical forests and relatively easy
to collect with each of the three methods. Winged
540 Lopes et al.
Hymenoptera species (presence/absence)
Pseudomyrmex unicolor
Pseudomyrmex tenuis
Pseudomyrmex rochai
Pseudomyrmex oculatus
Nonus sp1
Nesomyrmex brasiliensis
Genero23 sp1
Genero22 sp1
Dolichoderus bispinosus
Dolichoderus attelaboides
Crematogaster snellingi
Camponotus sp2
Camponotus latangulus
Brachymyrmex sp3
Brachymyrmex sp2
Azteca sp6
Azteca sp3
Wasmannia auropunctata
Tapinoma amazonae
Strumigenys trinindadensis
Pheidole sp25
Pheidole sp1
Paraponera clavata
Idris sp2
Heterospilus sp1
Gnamptogenys horni
Genero2 sp1
Genero12 sp3
Cephalotes palles
Azteca sp5
Azteca sp4
Crematogaster brasiliensis
Crematogaster nigropilosa
Ochetomyrmex neopolitus
Crematogaster tenuicula
Solenopsis sp1
Monomorium pharaonis
Heterospilus sp3
Crematogaster limata
Brachymyrmex sp1
Wasmannia scrobifera
Trachymyrmex diversus
Ochetomyrmex semipolitus
Nylanderia steinheili
Neoponera unidentata
Gnamptogenys moelleri
Genero10 sp1
Crematogaster erecta
Pheidole biconstricta
Solenopsis geminata
Utetes sp1
Trachymyrmex bugnioni
Tapinoma melanocephalum
Solenopsis sp4
Solenopsis sp2
Probaryconus
Pheidole sp9
Pheidole sp8
Pheidole sp6
Pheidole sp5
Pheidole sp4
Idris sp3
Hormius sp2
Hormius sp1
Horminus sp2
Heterospilus sp2
Gigantiops destructor
Genero3 sp1
Genero25 sp1
Genero21 sp1
Genero20 sp1
Genero18 sp1
Genero11 sp2
Genero1 sp2
Genero1 sp1
Dolichoderus inpai
Crematogaster sp1
Crematogaster sotobosque
Crematogaster longispina
Crematogaster flavosensitiva
Cephalotes spinosus
Cephalotes bruchi
Camponotus rectangulus
Baeus sp1
Azteca sp2
Aphaereta sp1
Allomerus octoarticulatus
Ordered plots by sampling method
Hymenoptera, such as parasitoids, on the other hand, were
more common in the Amazonas-trap than in the other
methods because of the increased facility of collecting
winged individuals. However, how many species were not
sampled by beating and manual sampling is not a simple
question to answer. There were only five winged hymenopteran species collected with the beating tray and three
by visual inspection. For the Amazonas-trap this bias was
minimized, as we collected at least 15 winged Hymenoptera species.
Overall, the number of unique families collected was
also higher using the new trap than the other methods. For
instance, orthopterans that are highly mobile individuals
were only sampled using the Amazonas-trap. Other herbivorous winged, agile, and sometimes difficult to collect
individuals, such as sap-suckers, were also more abundant
in the Amazonas-trap. However, the abundance of overall
leaf-feeders (mainly orthopterans and Coleopterans) did
not differ among the sampling methods. Therefore,
depending of the herbivorous taxa, entirely enveloping the
plant may not necessarily be a better option.
Sorting plant debris under the stereomicroscope also
substantially increased the efficiency of the new method
for wood-fungi feeders. This guild is composed mainly by
Figure 5 Distribution of Hymenoptera
species sampled with the three collection
methods on Protium saplings. The
columns represent the plots. The 10
columns on the left (red bars) represent
the Amazonas trap, the 10 columns in the
middle (blue bars) the beating tray, and
the 10 columns on the right (green bars)
the manual collection. [Colour figure can
be viewed at wileyonlinelibrary.com]
small cryptic individuals, such as Collembola and Psocoptera that live under the bark of the trees and between
decomposing fine organic matter. Collembola are very difficult to observe and collect manually due to their small
size and agility. For comparison, in the Amazonas-trap
samples, 188 springtails were collected, compared to 79
individuals sampled by beating tray and eight individuals
sampled by hand (Table S1).
Although not directly included because of the lack of
knowledge of arthropod taxonomy in tropical forests, the
collection of spiders and mites indicated very promising
results using the new sampling method. The Amazonastrap sampled more spiders than the other methods. In fact,
the number of spiders sampled with the Amazonas-trap
was similar to the number of ants, which is regularly cited
as the most abundant invertebrate taxon on plants (Stork,
1988; Ellwood & Foster, 2004). Other predators were also
better sampled, suggesting that the Amazonas-trap provides more robust and comprehensive pictures of insectplant assemblages in hyper-diverse tropical forests.
Despite the higher efficiency, one limitation of the
new insect trap proposed is the time of installation; it
takes more time than the two other methods. However, the greater time spent installing and using the
Unraveling understory plant-inhabiting arthropod fauna 541
Ant
60
Arachnida
60
a
40
Insect predator
60
40
a
40
a
a
20
b
20
20
a
c
0
0
Leaf−feeder
Sap sucker
b
Wood−fungi feeder
a
b
20
a
b
b
b
Parasitoid
40
a
20
20
b
a
b
b
Be
ati
ng
tra
y
ap
−tr
as
az
on
b
Am
tra
y
ng
ati
Be
−tr
as
az
on
Am
Ma
nu
al
0
ap
0
l
40
ua
60
Ma
n
60
Am
az
on
as
Omnivorous
l
0
ua
0
ap
0
20
Ma
n
a
40
tra
y
a
20
40
ng
a
60
ati
40
60
Be
60
−tr
Abundance of individuals
b
0
Figure 6 Abundance (no. individuals) of eight arthropod functional groups found on Protium saplings sampled with the three collection
methods: Amazonas-trap, beating tray, or manually. Means within a panel capped with different letters are significantly different (Tukey’s
post hoc tests: P<0.05). The boxes and whiskers represent the 50th and 95th percentile around the median (bold line), respectively. The
dots indicate outliers. [Colour figure can be viewed at wileyonlinelibrary.com]
Amazonas-trap is balanced by the collection of more
individuals and species per plant. The results from the
rarefaction curves per unit of time indicated that the
three collection methods are equally time-efficient,
accumulating the same number of insect families per
unit of time. For Hymenoptera species composition,
the efficiency of the three methods was also equivalent. This result is probably due to the ease of collecting Formicidae by the three methods, which was the
richest Hymenoptera family in this study.
The new Amazonas-trap was the most effective sampling method tested for plant-associated invertebrates in
this hyper-diverse tropical forest understory. Our results
indicate that plants harbor a diverse invertebrate-rich
assemblage, which may generally be undersampled when
using the traditional sampling methods. The Amazonastrap has great potential to be used for targeted collection
for behavioral studies, through observation of live insects
in the trap, and also for ecological studies (community or
population), as well as for the study of relations between
542 Lopes et al.
Figure 7 Rarefaction curves for Hymenoptera species and insect families sampled with Amazonas-trap, beating tray, and manual
collection, per unit of time. The continuous lines represent accumulation and the polygon areas represent 95% confidence intervals.
[Colour figure can be viewed at wileyonlinelibrary.com]
herbivorous insects and their host plant architecture,
chemical profiles, and anti-herbivore functional traits. The
new method may also be applied in the monitoring of
insect pests, studies on interaction between herbivores and
parasitoids (e.g., for biological pest control), and finally
for long-term monitoring of insect species distribution in
responses to climate changes (Basset et al., 2017).
Acknowledgments
We are thankful for the active participation of Eleonore Bernardo during the conception of the many prototypes created
prior to the finalized version of the trap used in this study.
We thank the Fundacß~ao de Amparo a Pesquisa do Estado
do Amazonas (FAPEAM), the Collaborative training for the
study of beta-diversity in tropical forests (TREEBEDIV), and
the Agence Nationale de la Recherche (ANR-13-BSV7-0009)
for support. A European Research Council (#669609) and a
GACR grants (19-15645Y) supported G. Lamarre during the
writing of the paper. We are thankful to Conselho Nacional
de Desenvolvimento Cientıfico e Tecnol
ogico (CNPq) for
the scholarship to the first author. F. Baccaro received a productivity grant from CNPq (3096002017-0).
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Supporting Information
Additional Supporting Information may be found in the
online version of this article:
Figure S1. Installation and procedure of the Amazonastrap. (A) Tying on the plant stem. (B) Closing of velcro
and installation of the aluminum tube. (C) Lifting and
closing up of the collector. (D) Agitation of the plant. (E,
F) Collection of specimens. This test tree is 3.5 m tall and
2 m in diameter.
Table S1. Abundance of arthropod classes, insect families, and hymenopteran species in 180 Protium plants distributed in 10 plots at Reserva Ducke, Manaus, Brazil.