Oncideres saga Dalman : first record damaging Stryphnodendron adstringens Mart . Coville ( Fabaceae ) in Brazil Oncideres saga

Beetles of the genus Oncideres, known as twig girdlers, girdle and detach branches and tree trunks for oviposition (Lemes el al., 2015). This action interrupts the sap flow from the tree, making the branch more nutritious, with a high nitrogen and phosphorus content, ideal for their larvae development (Calderón-Cortés et al., 2016, Correa et al., 2019). These longhorn beetles are exclusive to the Americas (Monné and Bezark 2009), with damage registered throughout Brazil, especially on trees of the Fabaceae family (Lemes et al., 2014a, Lemes et al., 2015, Corrêa et al., 2019). The bark of Stryphnodendron adstringens (Mart.) Coville is used in the traditional medicine because of its antidiabetic, antifungal, anti-inflammatory and healing properties (dos Santos et al., 2018). However, the removal of the bark, in an inappropriate way, may lead to tree death and, therefore, the use of leaves, that also have these properties, may turn this extractivist activity more sustainable (Sabino et al., 2018). Abstract Oncideres females girdle tree branches of the Fabaceae family, interrupting the sap flow and turning the wood conditions ideal for their larvae development. The bark of Stryphnodendron adstringens (Mart.) Coville, a species native to the Brazilian Cerrado, is widely used in the traditional medicine. The objectives were to report, for the first time, Oncideres saga (Dalman), using S. adstringens as a host and to describe the pattern of branch girdling and oviposition distribution by this insect on these branches. The diameter at the base and the length of the girdled branches were measured and the number of incisions made by the O. saga females to oviposit, per branch section (basal, median and apical), counted. The emerged specimens were counted and the diameter of the exit holes measured. The average diameter at the base of the girdled branches was 2.5 ± 0.16 cm and the length was 90.6 ± 4.6 cm. The average number of incisions per branch was 37.7 ± 2.7. Damage by O. saga can reduce the growth and cause losses on S. adstringens, a tree with great extractivism potential.,


Introduction
Beetles of the genus Oncideres, known as twig girdlers, girdle and detach branches and tree trunks for oviposition (Lemes el al., 2015). This action interrupts the sap flow from the tree, making the branch more nutritious, with a high nitrogen and phosphorus content, ideal for their larvae development (Calderón-Cortés et al., 2016, Correa et al., 2019. These longhorn beetles are exclusive to the Americas (Monné and Bezark 2009), with damage registered throughout Brazil, especially on trees of the Seed and fruit borers, such as Acanthoscelides gregorioi (Pic), Cydia tonosticha (Meyrick), and larvae of Holcocera cerradicola (Clemens) (Adamski andRibeiro-Costa, 2008, Silva andZampieron, 2016) damage S. adstringens, but there are no records on damage to its non-reproductive parts. The knowledge on the hosts and distribution of Cerambycidae borers may reduce and prevent their damage (Corrêa et al., 2020).
The objectives of this study were to report, for the first time, a twig girdler beetle damaging S. adstringens and to describe the pattern of girdled branches and the oviposition distribution on these branches by this insect.

Material and Methods
Three branches of S. adstringens, fresh girdled and fallen to the ground, were collected in a Cerrado area on the margins of the Federal Highway BR-451 in the municipality of Olhos d 'Água, Minas Gerais, Brazil (17° 13'25,1724 " S, 43° 40'19.3836 " W, 820 m), next to an Eucalyptus plantation in July 2018.
The diameter at the base and the length of the girdled branches were measured with a caliper (0.05 mm precision) and a millimeter tape (1.0 cm precision), respectively. The number of secondary branches and incisions, made by the females to lay eggs (Figure 1a), were counted by branch section (basal, median and apical).
The girdled branches were stored in 100 L closed plastic bags, with small holes for air entry, and kept at 24.1 ± 0.16 °C (temperature) and 57% ± 3.14% (relative humidity) between July 2018 and September 2019. These branches were weekly removed, wet with a watering can, left out to lose the moisture excess and placed back in the bags.
The emerged beetle specimens were quantified and conditioned in 70% alcohol for identification through literature and specialists consultation. Adult individuals of the morphospecies that emerged were pinned, tagged and sent to Dr. Miguel Monné (Museu Nacional, Universidade Federal do Rio de Janeiro -UFRJ, Rio de Janeiro, State of Rio de Janeiro, Brazil), for identification.

Results
A total of 38 beetles, from two species of the Cerambycidae family, were collected. The species, that girdled the branches, was O. saga (Figure 1b), the only twig girdler that emerged from the branches. Oncideres saga adults emerged from July to August 2019. Oncideres saga adults emerged through ellipse shaped holes (Figure 1c) with an average length and width of 0.71 ± 0.45 cm and 0.35 ± 0.20 cm, respectively. Thirty-two individuals of Eriphus biguttatus (Germar), an inquiline of the branches girdled by O. saga, emerged from December 2018 to September 2019 (Figure 2).
The diameter at the base and the length of the S. adstringens girdled branches were 2.34, 2.90 and 2.50 cm and 82, 92 and 98 cm, with three, five and three secondary branches, respectively. The number of incisions per branch was 37.7 ± 2.7. The number of egg incisions (Figure 3) was higher in the median section of the branches (16.3 ± 1.2), followed by the apical and basal, 11.7 ± 1.4 and 9.7 ± 1.8, respectively.

Discussion
Oncideres saga damages trees of several plant families of agricultural and forestry importance such as Acacia mangium Willd (Fabaceae) (Magistrali et al., 2013)  inhabiting girdled branches of S. adstringens, indicates that they are a habitat with adequate food for the twig girdler larvae and inquiline species as found for A. mangium girdled branches (Lemes et al., 2015).
The preference of O. saga females to lay their eggs, preferably in the median section of the branches, may be associated with the quantity of wood volume available for the development of their larvae (Lemes et al., 2014b). The volume, the surface area and the length of the girdled branches correlate with the number of eggs laid and larva hatched by twig girdlers (Lemes et al., 2014c). These beetles lay eggs far from the edges, preventing their larvae from leaving the branches and ensuring adequate food reserves in any direction they move (Paulino Neto et al., 2006, Lemes et al., 2013. The exit holes of O. saga in S. adstrigens were smaller than those of this beetle and O. dejeani in Parapiptadenia rigida (Benth.) Brenan (Fabaceae), 1.04 ± 0.18 cm and 0.85 ± 0.15 cm and 0.97 cm ± 0.18 and 0.79 cm ± 0.18 in length and width, respectively (Link et al., 1994) and those of O. cervina in branches of O. puberula, in Santa Maria, Rio Grande do Sul, 0.97 cm ± 0.23 long and 0.81 cm ± 0.15 wide (Witeck Neto et al., 2015). Differences between these exit holes dimensions may be associated to the variation in the adult size of each species. On the other hand, differences within individuals of the same species, but using different tree species as host, such as O. saga in S. adstrigens and P. rigida, may be associated with the quantity and quality of the wood used as food by their larvae, affecting the size of the adults emerged.
This is the first record of a twig girdler beetle damaging S. adstrigens. Oncideres saga damage may reduce the growth and cause losses on the S. adstrigens trees, which have great extractivist potential. The female twig girdler lays more eggs in the median section of S. adstrigens girdled branches, ensuring the development and survival of their offspring.