Insect galls on Mikania glomerata ( Asteraceae ) in an area of Atlantic Forest in Viçosa ( Minas Gerais , Brazil )

Mikania glomerata (Asteraceae) hosts eight gall midge species (Diptera: Cecidomyiidae), each one responsible for a different gall morphotype. In a survey conducted in Recanto das Cigarras, Viçosa, Minas Gerais state (Brazil), we found three of these eight gall midges: Liodiplosis cylindrica, L. spherica, and Asphondylia glomeratae, each exhibiting a low infestation rate. This study offers an updated geographic distribution of these three gall midge species, recorded for the first time in Minas Gerais state.

Mikania glomerata Spreng.(Asteraceae), commonly known as "guaco", is native to Brazil, Uruguay, Argentina, and Paraguay, and used in folk medicine to treat rheumatism and respiratory diseases (Celeghini et al. 2006;Agra et al. 2008).In Brazil, it occurs in the Northeast, Southeast, and South regions, in the Cerrado and Atlantic forest biomes (Ritter and Miotto 2005).It is a shrubby climbing plant, woody, with cylindrical and slender stem, and without tendrils.The leaves are opposite, triangular, shiny green, slightly dark in the adaxial surface, and the flowers are yellowish and white (Vidal et al. 2006).
This plant is attacked by eight species of gall midges (Diptera, Cecidomyiidae), Alycaulus globulus Gagné, 2001, Asphondylia glomeratae Gagné, 2001, Asphondylia moehni Skuhravá, 1989, Liodiplosis conica Gagné, 2001, L. cylindrica Gagné, 2001, L. spherica Gagné, 2001, Mikaniadiplosis annulipes Gagné, 2001, and Perasphondylia mikaniae Gagné, 2001.Each of these species induces a different gall morphotype (Gagné et al. 2001).In spite of being described from the state of Rio de Janeiro, these gallers occur also in the state of São Paulo (Maia et al. 2008).Mendonça et al. (2014) recorded a spherical, green, woody, glabrous, leaf and stem gall induced by a Cecidomyiidae, but the gall midge species was not identified by the authors.Although this gall regards those induce by L. spherica, except for the woody tegument, we cannot affirm that this species is the inducer of the gall found by Mendonça et al. (2014).It would be necessary to obtain material from the inducer to make a more accurate identification.
So, until now, these species have been recorded in only two states, Rio de Janeiro and São Paulo.
The objective of this study is to contribute to the knowledge of the geographic distribution and abundance patterns of the gall midges associated with Mikania glomerata.
We surveyed an Atlantic Forest area, known as Recanto das Cigarras (Figure 1), situated in the Campus of the Universidade Federal de Viçosa, in Minas Gerais state (Brazil) (Figure 2).The vegetation along the main trail "Mata da Biologia" was examined in search for the host plant and insect galls.The geographic coordinates and altitude of the beginning and the end of the trail were obtained using GPS (datum: SIRGAS2000) (20°45ʹ24ʺ S, 042°51ʹ39ʺ W, altitude: 699 m; 20°45ʹ21ʺ S, 042°51ʹ28ʺ W, altitude: 729 m).The map was made based on an original map from IBGE (2015).The number of individuals of Mikania glomerata was verified as well as the number of each gall morphotype in 20 leaves per individual (20 leaf blades and 20 petioles).Galls were photographed using a digital camera.Samples of each morphotype were collected and transported individually in labeled plastic bags.The fieldwork was done by the authors for four hours on 13 August 2015.
In the laboratory, the galls were dried and then deposited as voucher material (number 224629) in the Herbário do Museu Nacional (MNRJ).As each galling species induces a distinct morphologically gall, the gall is considered as a taxonomical character and can be used to indicate the presence of the galler (Carneiro et al. 2009).
The gall morphotypes were deposited in the Cecidomyiidae collection of Museu Nacional (MNRJ), and were labeled as follows: 1) Viçosa, MG.All morphotypes were scarce.We found only six cylindrical galls in three individuals, two petiole galls in two individuals (one per individual), one vein gall in one individual, and one spherical gall in a single individual (Table 1), totaling 10 galls.There was no simultaneous occurrence of different gall morphotypes in a same leaf blade or even in the petiole and leaf blade.Petiole/vein and spherical galls occurred individually (only one gall per leaf), while the cylindrical ones occurred gregariously (three or two galls in the same leaf) or individually.The infestation rate was low: among the total of leaf blades (n=80), only five were galled (6.25%), whereas among the petioles (n=80), only two were galled (about 2.5%).
Although Mikania glomerata hosts eight galling species in Brazil, only three were found in the present study: Asphondylia glomeratae, Liodiplosis cylindrica, and L. spherica, and they are recorded for the first time in the state of Minas Gerais.The previous records included the states of Rio de Janeiro and São Paulo (Table 2).The updated geographic distribution of Asphondylia glomeratae, Liodiplosis cylindrica and L. spherica in Brazil is shown in Figure 6.
All three species presented a wide distribution occurring in both restinga and ombrophilous forest areas.Asphondylia glomeratae had the most restricted geographical distribution, occurring in only five of the 10 localities already sampled by other authors, as shown in Table 2. Liodiplosis cylindrica and L. spherica presented similar distribution being found in seven of these 10 localities, including the present study.Parque Nacional da Tijuca (Rio de Janeiro/RJ) and Reserva Biológica de Poço das Antas (Silva Jardim/RJ) were the unique localities not shared by these species, until now.Parque Nacional do Itatiaia (Itatiaia/RJ), Restinga de Bertioga (Bertioga/SP) and Recanto das Cigarras (Viçosa/MG) were the only sites where the three gall midge species were found (Table 2).
These results show the importance of sampling new localities to establish the geographic distribution limits of the galling insects.These data are primordial to future biogeographic studies as well as to the knowledge of the local biodiversity fauna.

Figures 1 and 2 .
Figures 1 and 2. The collection site of this study, Recanto das Cigarras in Universidade Federal de Viçosa, Minas Gerais (Brazil).1.The main trail.2. The entrance of the trail.