RODOLFO MOLINARIO DE SOUZA¹, NORIVALDO DOS ANJOS², JANAÍNA DE NADAI³, RODRIGO DINIZ SILVEIRA^4*, GLAUCIA CORDEIRO³

¹ Ms. Produção Vegetal, Departamento de Biologia Animal, Universidade Federal de Viçosa, Viçosa, MG. Brasil. 36571-000. molinariodesouza@yahoo.com.br

² Dr. Entomologia. Departamento de Biologia Animal, Universidade Federal de Viçosa, Viçosa, MG. Brasil. 36571-000. nanjos@ufv.br

^4* Autor para correspondencia. Dr. Entomologia. Departamento de Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG,
Brasil. 39100-000. silveirard@insecta.ufv.br

Introduction

Many problems have arisen with eucalyptus plantations, as has happened with other monocultures, and pest outbreaks are included among these problems. Some papers have reported on the occurrence of Psiloptera spp. attacking young plantations of eucalyptus in Brazil (Berti Filho 1981; Anjos and Majer 2003; Vellozo et al. 1953; Zanuncio et al. 1986; Ribeiro et al. 2001). Adults of these insects are tree defoliators that destroy the lateral branches and main shoot, stopping apical growth and reducing wood production (Anjos and Majer 2003). Since the knowledge on life history is one of the basic premises to a successful control of insect pests, sexual differentiation is basic to understand their reproductive habits (Weber 1976; Lima 2001). The purpose of this paper is to report on the morphological characters that allow sexing in Psiloptera pertyi (Laporte & Gory, 1836), without dissection.

Adults of P. pertyi were collected from Grão Mogol region, northeast of Minas Gerais State, in November 2003, were stored in plastic containers filled with 70% ethanol. Sexual identity was previously obtained through dissections to ascertain the presence of an aedeagus. Then the external morphology of determined males and females was studied. Morphological details were examined through stereoscopic 40X microscope.

We looked for characters that were useful to differentiate each sex, such as the shape of urosternites and elytra (Macrae 2003; De Nadai et al. 2005), sclerite colors (Rejzek 2007; Piper et al. 2005) and body measurements (Nelson 1994; De Nadai et al. 2005). Body length is the distance between the anterior margin of the head and the apex of elytra. The body width is the longest distance between lateral margins of body (Anjos 1992). Evaluation of morphological characters was carried out on 50 males and 50 females. Morphological measurements were then compared by one-way ANOVA.

Results

We note eleven abdominal segments for both males and females. The 1st to 5^th uromeres are distinguishable, but others are retracted inside the fifth. After relaxing the specimens and lifting the apical opening of the 5^th abdominal sternite, we located both the 7^th and 8^th uromeres in males, but only the 7^th in females.

In P. pertyi males, we found a sharp projection just in the central apex of the 7^th abdominal sternite (Fig. 1A). In contrast, females possess a deep notch in the same position (Fig. 1B). Additionally, we found a notch in the posterior border of 5th abdominal sternite for males; females have a rounded margin in the equivalent sternite. No consistent color differences were detected between males and females of P. pertyi. Females have body dimensions statistically larger than males (length: F = 63,68; d. f. = 1; P < 0,01 and width: F = 22,53; d. f. = 1; P < 0,01) (Table 1) but ranges are overlapping . So, adults can not be differentiated through length or width measurements.

According to Hastir and Gaspar (2002), sexual dimorphism in buprestids varies in different species, but most variations occur in margin shape of the last sternite abdominal. In some cases, as in Lampetis spp (De Nadai et al. 2005), this is applicable, but Acmaeodera lupinae Nelson, 1996 females have 5^th urosternite more elongated than in the male (Nelson 1996). According to Gigli (2007), body color may be used to differentiate sex in some buprestids. Females in Anthaxia nitidula (L., 1758) species have the head color different from body color, but males are uniformly colored along their body (Rejzek 2007). In contrast, females in Agrilus hyperici (Creutzer, 1799) species are uniformly colored while male beetles have their head color different from the rest of the body (Piper et al. 2005).

In insects, the females are usually larger than the males (Snodgrass 1993), but overlapping intervals for body dimensions were found by Nelson (1996) in Acmaeodera vanduzzei VanDyke, 1934; A. ephedrae Barr, 1942; A. constricticollis Knull, 1937 and A. barri Cazier, 1940 and by De Nadai et al. (2005) in Lampetis nigerrima (Kerremans, 1897), L. instabilis (Castelnau & Gory, 1836), and L. roseocarinata Thomson, 1878 (De Nadai et al. 2005). So, P. pertyi adults have similar dimensions. Finally, we conclude that adults of P. pertyi have morphological differentiations in the abdomen. Sexing adults in Buprestidae species should be done by checking the shape of the 7^th abdominal sternite, only after 5th abdominal sternite is opened for careful internal examination.

Acknowledgments

This work would not be possible without the financial support from CAPES. We are grateful to both of these institutions.

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Recibido: 18-ene-2007 - Aceptado: 28-oct-2007