Parkinsonia aculeata L. is a shrubby tree which has generally been considered North American, but according to Hawkins et al. (2007), South America is included in the original native range, with records in Argentina, Venezuela, Paraguay, and Brazil. In Brazil, it has a disjunct distribution, being found in northeast (“caatinga”) and in south (“campos”) (Lorenzi 2002). Similar disjunct distributions has been recorded for many other plants by Prado (2000), who explained the pattern based on climatic shifts in South America during the late Pleistocene. Thus, P. aculeata is clearly native to both the northeast and south regions of Brazil.

Parkinsonia aculeata is useful for ornamentation, shade, supply of wood, evergreen hedge, soil fixation, regeneration of degraded areas, medicine, and food. Because of its uses, P. aculeata has been introduced in many countries (Weber 2003) and, in some of them, it has became invasive. It has invaded rangelands in Texas and Arizona, and in Australia it is a serious weed of pastures and rangelands, where it forms dense impenetrable thickets (Woods 1992). In northeast Brazil, populations of P. aculeata were restricted almost always to semi-arid lakes which remained flooded part of the year, but in recent years populations have invading pastures, fields and open areas; in some areas there are dense thickets (L. A. de Andrade, Univ. Fed. of Paraiba, personal communication).

Several methods of control are used in Australia, one of which is biological control with the beetle Penthobruchus germaini (Pic), that was introduced into Australia and became wide-spread and damaging to P. aculeata (van Klinken 2006).

At the end of 2007 pods of P. aculeata were collected from Santa Maria (29°41′02″ latitude south; 53°48′25″ longitude west) and São Sepé (30°09′38″ latitude south; 53°33′55″ longitude west), Rio Grande do Sul, Brazil, in order to determine what insects were damaging seeds. The pods were packed in ventilated containers at room temperature. When adults emerged they were identified by the first author as P. germaini mainly by the distinctive pattern of vestiture on the dorsum (Fig. 1) and the format of valves and median sclerite in the internal sac of the median lobe of male genitalia that separate it from P. cercidicola Kingsolver (1973), previously confused by Terán (1962).

Fig. 1.

Penthobruchus germaini: 1. dorsal view (scale = 1.0 mm); 2. median lobe of male genitalia (scale = 0.5mm).

According to Kingsolver (1973) the native distribution of P. germaini includes Chile (Santiago) and Argentina (Santa Fé, Buenos Aires), so this species is recorded for the first time in Brazil. In view of the fact that the previously recorded localities in Argentina, mainly Santa Fé, are closer to both Santa Maria and São Sepe in Brazil, we consider these new places of occurrence part of P. germaini native distribution and not an introduction.

The range of bruchines typically overlaps the distribution of its hosts and P. aculeata also occurs in other Rio Grande do Sul locations, such as Parque do Espinilho, a conservation unit of Barra do Quaraí city, and Basin of Ibicuí River, so it is very probable that the distribution range of P. germaini includes these places if more collectings were done. However, it is difficult to predict the occurrence to northeast Brazil, even with the presence of the host plant.

Specimens of P. germaini are deposited in the Coleção de Entomologia Pe. J.S. Moure, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, Brazil. Now that P. aculeata is known to occur in northeast Brazil and the high potential for P. germaini to control P. aculeata because about 90–100% of cotyledons are destroyed during larval period preventing germination (Briano et al. 2002) and, at some sites in Australia, up to 95% of seeds are destroyed (Cochard & Jackes 2005), it is appropriate to begin research on seed predation by P. germaini in Brazil to understand the role of this species in this new country of occurrence.

SUMMARY

The seed beetle, Penthobruchus germaini, is a biological agent control for Parkinsonia aculeata in Australia. Collections of P.aculeata fruits in Brazil showed the presence of P. germaini for the first time in this country.