Treehoppers (Hemiptera, Auchenorrhyncha: Aetalionidae and Membracidae) from western Acre, Brazil, with emphasis on the fauna of Serra do Divisor National Park

Abstract The first list of Aetalionidae and Membracidae species for western Acre is presented, including the Alto do Juruá regions of Serra do Divisor National Park and the Campus Floresta of the Federal University of Acre. In total, 94 species of treehoppers were collected, of which Centrotinae (Membracidae) is recorded for the first time for Brazil (Abelus maculatus Schimidt), another 16 species are new Brazilian records, and 69 species (Aetalionidae and Membracidae) are new records for Acre. Data on type locality, geographic distribution and images of all species are presented. The males of Lophyraspis fenestrata Sakakibara & Creão-Duarte and Erechtia sanguinolenta (Fairmaire) are known for the first time. The species diversity was compared to four other treehopper surveys in the Amazon region, with similarity indices of about 43.6% for Colombian Amazon (at least 650 km away), 27.6% for Panguana Biological Research Station, Peru (250 km), 20.2% for Adolpho Ducke Forest Reserve, Brazil (1,600 km) and 8.5% for Villa Carmen Biological Station/Los Amigos Biological Station, Peru (600/700 km). The estimated richness of Serra do Divisor National Park was just over 70%, suggesting that local diversity could be significantly higher than that presented in this study.


Introduction
Treehoppers constitute a monophyletic group of three families within the Auchenorrhyncha hemipterans: the cosmopolitan Aetalionidae (6 genera, 42 species) and Membracidae (427 genera and more than 3,450 species), and the South American Melizoderidae (three genera and nine species), restricted to the south of Argentina and Chile (Dietrich et al. 2017, Hu et al. 2022).In Brazil, 16 species of Aetalionidae are listed in five genera, whereas 701 species are listed in 124 genera belonging to Membracidae (Evangelista et al. 2023a, b).
Treehoppers are phytophagous in all life stages, establishing an antagonistic interaction with host plants from more than 100 botanical families (Godoy et al. 2006).Although characterized by their phytophagous habit, no commercial interest occurs.Few species can act as agricultural pests, mainly due to the high population density and the damage caused by the egg laying in the plant tissue (Deitz & Wallace 2010).
These insects show various forms of social behavior, from solitary to gregarious forms.The gregarious, nymphal and imaginal generations overlap, and highly elaborate maternal care is displayed, such as egg and nymph guarding (Cocroft 2002, Lin 2006).Vibrational communication has already been reported in these hemipterans in male-to-male dispute, copulation and warning behavior (Cocroft 2001, Lin 2006).Generally, the gregarious species develop mutualistic relationships with assistant ants and other hymenopterans, exchanging their honeydew for protection against natural enemies (Godoy et al. 2006).Membracids also exhibit a complex and unique variety of pronotum shapes, with various types of projections, forms and colors, which gives them mimicry, camouflage, aposematism, and defense against predators (Evangelista et al. 2017).
The study presents the first inventory of treehoppers (Hemiptera: Aetalionidae and Membracidae) from western Acre in the Alto Juruá, within the Serra do Divisor National Park, including specimens collected at Campus Floresta of the Federal University of Acre.

Study area
The collection was conducted between May 12 and 18, 2019, in two areas of western Acre: (I) the Serra do Divisor National Park, around the Pé da Serra Community (07⁰27'05.06"S73⁰39'52.9"W), in the municipality of Mâncio Lima; and (II) the Campus Floresta of the Federal University of Acre (7°33'37.0"S72°42'48.3"W), in the municipality of Cruzeiro do Sul (Figure 1).
The state of Acre has 45.66% of its territory made up of Protected Natural Areas, i.e., Indigenous Lands, Full Protection or Sustainable Use Conservation Units (Acre 2010, Bernarde et al. 2017).One of the protected areas included is the Serra do Divisor National Park (hereafter SDNP), which is located in the municipality of Mâncio Lima.The SDNP has about 8,350 km² and is located on the border with Peru, making it one of the largest national parks of Brazil.Its governance comes from the Brazilian Institute for Environment and Natural Resources (IBAMA) (Acre 2010).
The topography of the region is formed by plains and hills whose altitudes vary from 130 to 600 m.The highest altitudes at Acre are found in the SDNP.The highest locations in the SDNP physiographic complex include a transient climate range from humid to super-humid, with a relative humidity index of about 100%.The climate of the region is Am based on the Köppen classification (SEMA 2012).The annual temperature ranges from 24.4⁰C to 28.8⁰C (Acre 2010).The temperature in June and July can drop considerably under Amazonian standards, up to 7⁰C (Bernarde et al. 2017, Esteves & Luz 2019).Precipitation is common all year round, with precipitation rates above 2,500 mm/year (IBAMA et al. 1998).
Two important phytoecological regions are found in the area of the SDNP the Dense Ombrophilous Forest, which predominates in the whole Amazon, and the Open Ombrophilous Forest.However, other plant formations can be characterized, which differ mainly in the quality of the soils on which they occur (SEMA 2012).
The Campus Floresta is the third campus of the Federal University of Acre (hereafter UFAC) and is situated in the municipality of Cruzeiro do Sul, at the western end of Acre.This is the second largest city in Acre, with an area of 8,816 km² (Bardales et al. 2021).The phytophysiognomies and abiotic conditions of the UFAC are similar to those described for the SDNP.

Specimen collection
The collections of specimens were made with the permission of SISBIO (#68353-1).The collection methodology followed Cabral et al. (2020) except for the lower sticky cards that were not used and the total number of light traps was only four.Among the 30 active collections, 29 were carried out in the SDNP and one in the UFAC.

Identification
Taxonomic identification was done comparing collected specimens with material deposited in the Coleção Entomológica of the Departamento de Sistemática e Ecologia (DSEC) of the Federal University of Paraíba, images of type specimens, original descriptions and identification keys for genera and species.Taxonomic determination was performed by the first and second authors, except for specialists in some groups, such as Heteronotinae and Cladonota Stål.The species list follows the classification of McKamey (1998) and Wallace & Deitz (2004).Species not identified (referred to as "sp.") are likely undescribed species.However, the description of these species depends on genera revisions, which are not the subject of this study.
Each species is accompanied by type locality given in its original form, material examined, distribution and comments.The information regarding distribution was extracted mainly from the catalogs organized by Funkhouser (1927), Metcalf & Wade (1965) and McKamey (1998), as well as from recent bibliography.
Data labels are arranged according to the following criteria: bracketed information complements abbreviated words; backslash indicates different lines within the same label; vertical slash indicates different labels.Family, subfamily, tribe, genus and species are listed alphabetically and preceded by author and year, following Deitz & Wallace (2010).Species listed as new records for Brazil are highlighted in the comments.All specimens are vouchered and deposited at the Entomological Collection of the Department of Systematics and Ecology (DSEC), from Federal University of Paraíba, Brazil.

Imaging
Photographs of the specimens in vivo were obtained with a Nikon D3200 camera.Images of the pinned specimens were taken in left lateral view and obtained using a Leica® M205C-A stereomicroscope coupled with DFC450 camera and Leica® Application Suite (LAS) image capture system.The processed images were later edited using Adobe Photoshop CS5.

Data analysis
EstimateS 9.1 software (Colwell 2013) was used to estimate species richness through the Chao1 and Chao2 estimators and to construct the collector curve to SDNP.The data were submitted to 1000 randomizations without replacement, in classic mode without bias-correct formula (Walther & Moore 2005).
The subfamilies with the highest species diversity were Smiliinae, Membracinae, and Biturritiinae, comprising more than 78% of the total species richness observed.These subfamilies also accounted for 81% of the overall abundance.Among the tribes studied, the most abundant ones were Membracini, Tragopini, and Polyglyptini, contributing to nearly 60% of the total insect abundance observed.The ten most abundant species represent 45.76% of the total abundance.Of the 94 species collected, 11 were represented by two individuals (doubletons) and 29 were represented by only one (singletons) (Table 1).The richness values observed for the SDNP represent 71.43% (Chao1) and 72.22% (Chao2) of the estimated richness.
Comments.The species was described on the basis of a single specimen.
The specimens collected exhibit variations in the intensity of the color spot and the apical half of the tegminas.Some of these specimens match the description of Fairmaire (1846).According to McKamey (1998), this species is already registered in Brazil, but with no precise locality.This is the first record of the male.They are similar to females, but smaller and with a larger yellow-orange spot on the median carina.

Discussion
In this study 94 species of treehoppers were collected, of which seventeenspecies are new records of Membracidae for Brazil, including the first record of the subfamily Centrotinae for the country, Abelus maculatus Schimidt.
Most of the specimens were captured by active collection, with just eight specimens collected with sticky cards, and none with light traps.Low field temperatures could be responsible for the poor efficiency of these last two sampling methods, since they require the treehoppers to be active, which is reduced at lower temperatures (Jocson et al. 2019;Leith et al. 2020).In addition, monkeys were seen destroying sticky cards placed in the canopy.
The estimated richness by Chao1 and Chao2 for SDNP were 71.43% and 72.22%, respectively, suggesting that local diversity may be much higher, especially regarding the groups with solitary behavior and thus more challenging to detect, such as Centrotinae, Darninae, Endoiastinae, and Nicomiinae.Cabral et al. (2020) proposed a collection protocol for Membracidae to be applied in humid forests, and the authors highlighted that 18.7% of the collected species were obtained exclusively by canopy cards, 17.6% only by light trap, and 2.0% by cards thrown into the understory, reinforcing that the use of other collection methods can increase the richness sampled from the area.
Creão-Duarte & Sakakibara (2009) listed 56 membracid species for the Adolpho Ducke Forest Reserve, where five of the nine current subfamilies were represented, being Smiliinae and Membracinae the richest taxa with 18 and 16 species, respectively.The subfamilies Centrotinae, Centronodinae, Endoiastinae and Nicomiinae had no representatives included in their listing.This study found 19 species shared with those of the Adolpho Ducke Forest Reserve.Schulze et al. (2019) listed 74 treehopper species (73 Membracidae and one Aetalionidae) analyzing 12 other works with the fauna in Panguana, from 2003 to 2016.The authors added to their list four species of Smiliinae and Membracidae from material deposited at the Center of Natural History, in Hamburg.Once again, the species of the Smiliinae and Membracinae had the greatest richness, 37 and 23, respectively.No records of Centrotinae, Endoiastinae and Centronodinae were made.This work has 26 species in common with those on our listing.Lin et al. (2019) listed 114 specimens, belonging to 44 species of treehoppers (two of Aetalionidae and 42 of Membracidae) using diverse collection methods such as Malaise traps (ground and canopy), flight interception traps, blue/yellow sticky cards, UV light traps, pitfall traps, sweeping nets, and manual collection.Except for Endoiastinae, all other subfamilies were represented on their checklist.Smiliinae and Heteronotinae were the richest, with 15 and nine species respectively.This work only shares seven species when compared to our listing.Flórez-V. et al. (2015) by reviewing literature and collections (3,744 specimens in ten Colombian collections), and conducting field work between 2011 and 2014, recorded 474 species belonging to 116 genera, with specimens from all Membracidae subfamilies.In addition, 1,449 host plants and 262 hymenopterans associated with membracids were documented.Among the Colombian listed species, 41 are common to the list that we compiled.

Figure 1 .
Figure 1.Map of the study area from western Acre, Brazil.SDNP -Serra do Divisor National Park (black dot), and UFAC -Campus Floresta of the Federal University of Acre (black triangle).

Table 1 .
Treehoppers (Hemiptera: Aetalionidae and Membracidae) collected in the Serra do Divisor National Park (SDNP), Comunidade Pé da Serra, municipality of Mâncio Lima and Campus Floresta of the Federal University of Acre (UFAC), municipality of Cruzeiro do Sul.New records to Brazil are highlighted with *.
(Sakakibara, 2012)razil.The species is currently listed as incertae sedis(Sakakibara, 2012)because it fits more naturally in the genus Membracis Fabricius.The specimens have been compared with the images of the holotype of Erechtia trinotata Funkhouser and have proved identical, but the nomenclatural acts are outside the scope of this study.