Available online at www.sciencedirect.com Biological Control 43 (2007) 317–322 www.elsevier.com/locate/ybcon Ecology and impact of Allorhogas sp. (Hymenoptera: Braconidae) and Apion sp. (Coleoptera: Curculionoidea) on fruits of Miconia calvescens DC (Melastomataceae) in Brazil Francisco R. Badenes-Perez a,*, M. Tracy Johnson b a Pacific Cooperative Studies Unit, University of Hawaii at Manoa, Honolulu, HI 96822, USA b Institute of Pacific Islands Forestry, USDA Forest Service, PSW Research Station, Volcano, HI 96785, USA Received 19 April 2007; accepted 23 August 2007 Available online 1 September 2007 Abstract Two fruit-feeding insects, a gall wasp, Allorhogas sp. (Hymenoptera: Braconidae), and a beetle, Apion sp. (Coleoptera: Curculionoi- dea), were evaluated in their native habitat in Brazil as potential biological control agents of Miconia calvescens DC (Melastomataceae). Allorhogas sp. occurred at two out of three field sites with native populations of M. calvescens, and Apion sp. occurred at all three sites. Both species exhibited aggregated distributions among M. calvescens trees sampled at each site. Allorhogas sp. infested 9.0% and 3.8% of fruits at each of two sites. The number of larvae and pupae of Allorhogas sp. and/or an unidentified parasitoid (Hymenopetera: Eulo- phidae: Tetrastichinae) ranged from one to five per infested fruit. Fruits infested with Allorhogas sp. were 20% larger and had 79% fewer seeds than healthy fruits. Although adults of Apion sp. were found on leaves and inflorescences of M. calvescens at all three sites, larvae and pupae were found in fruits at only one site, where a maximum of 1.4% of fruits were infested. Fruits infested by Apion sp. contained only one larva or pupa, and were 15% smaller and had 62% fewer seeds than healthy fruits. While a variety of apionids have been used for biological control in the past, this is the first time a braconid wasp has been considered for biological control of a weed. Ó 2007 Elsevier Inc. All rights reserved. Keywords: Miconia calvescens; Phytophagous gall wasp; Allorhogas; Apion; Weed management; Seed; Fruit size 1. Introduction Medeiros et al., 1997). Biological control is considered an essential tool for long term management of M. calvescens The velvet tree, Miconia calvescens DC (Melastomata- (Smith, 2002). Classical biological control of weeds via ceae), is a small tree native to Central and South America the introduction of natural enemies from the native habitat that is considered a serious threat to natural ecosystems in of the weed is one of the most important methods to man- Hawaii and other Pacific islands because of its ability to age alien invasive weeds (Denslow and Johnson, 2006; invade intact forests of these islands, having already dis- Julien and Griffiths, 1998). Prerelease studies in the native placed over 65% of the native forest in Tahiti (Medeiros habitat of the invasive weed can be challenging to conduct, et al., 1997; Meyer, 1998; Meyer and Florence, 1996). Her- yet are fundamental to assess the potential of biological bicidal and mechanical removal are the main methods used control agents (Goolsby et al., 2006). to contain the spread of M. calvescens, but control is diffi- The success of M. calvescens as an invasive plant is partly cult and costly, especially in remote areas (Kaiser, 2006; due to its prolific reproduction, with one mature tree flower- ing up to 3 times per year and bearing up to 220 inflorescenc- es that can produce more than 200 fruits each with 25–200 * Corresponding author. Present address: Department of Entomology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 seeds per fruit (Medeiros et al., 1997; Meyer, 1998). The Jena, Germany. Fax: +49 0 3641 57 1502. impact of seed feeders in weed biocontrol has yielded mixed E-mail address: [email protected] (F.R. Badenes-Perez). results (Goolsby et al., 2006). Seed-feeders are sometimes 1049-9644/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.biocontrol.2007.08.007 318 F.R. Badenes-Perez, M. Tracy Johnson / Biological Control 43 (2007) 317–322 considered useful biological control agents of weeds only in Guaraciaba, and Vic¸osa, all in the state of Minas Gerais. seed-limited plant systems (Crawley, 1992; Myers, 1978). In Minas Gerais is the southeastern part of Brazil (Planalto the case of M. calvescens, even if it is not seed-limited, since it Central) and the region is noted for tropical climate and is dispersed by birds feeding on fruit and a sufficient measure hilly terrain. Field sites were in secondary Atlantic forest of biological control success could be to reduce its spread, heavily disturbed by adjacent agricultural and eucalyptus insects that feed on inflorescences and/or fruits of M. calves- plantations. The area sampled in each field site was approx- cens could help managing this weed. Apion spp. (Coleoptera: imately 1 ha and contained 15–35 adult plants bearing infl- Curculionoidea) and relatives, have been used with some orescences depending on the site. Distance between M. success in some cases of biological control of weeds in Cyti- calvescens plants was highly variable, some plants being sus scoparius (L.), Emex spp., Mimosa pigra L. and Ulex right next to each other and others several hundred meters europaeus L. (Julien and Griffiths, 1998; McClay and De apart. Altitude for Dionı´sio, Guaraciaba, and Vic¸osa is Clerck-Floate, 1999), but not in others (e.g., Hill et al., 345, 570, and 645 m above sea level, respectively. Distances 1991). The species of Apion studied here was suggested as a between the field sites were approximately 120 km between possible seed-feeder associated with M. calvescens after Dionı´sio and Guaraciaba, 145 km between Dionı´sio and being found on M. calvescens leaves (Picanc¸o et al., 2005). Vic¸osa, and 60 km between Guaraciaba and Vic¸osa. While dissecting fruits to confirm the presence of Apion sp. larvae in M. calvescens fruits and to assess their impact on 2.2. Insect abundance M. calvescens fruit, we accidentally found Allorhogas sp. and we also included it in the study. The genus Allorhogas 2.2.1. Apion sp. adults on inflorescences and leaves is distributed worldwide and was once presumed, like all Bra- To assess abundance and distribution of Apion sp., infl- conidae, to be exclusively parasitic of other insects (Maceˆdo orescences and leaves of M. calvescens were sampled at and Monteiro, 1989; Shenefelt and Marsh, 1976). Since the each of the three field sites. In April 2006, five inflorescences first phytophagous braconid was documented by Maceˆdo in each of 10 randomly selected trees at each site were sha- and Monteiro (1989), other cases of plant feeding Hymenop- ken individually over a 40 · 20 · 10 cm white plastic tray to tera have been described and gall-inducing species have been dislodge and collect Apion sp. adults. In June 2006, leaves reported in Brazil and Costa Rica on the plant genus Conos- were examined in 10 randomly selected trees at each site, tegia (Melastomataceae), Pithecellobium (Fabaceae), and and all adult beetles were collected with an aspirator. Stryphnodendron (Fabaceae) (Austin and Dangerfield, Vouchers specimens were deposited in the Zoology 1998; Infante et al., 1995; Maceˆdo and Monteiro, 1989; Museum of the Department of Biology at the University Marsh et al., 2000; Wharton and Hanson, 2005). Addition- of Costa Rica. ally, here we report a gall inducing Allorhogas sp. on the genus Miconia (Melastomataceae). Although no detailed 2.2.2. Allorhogas sp. and Apion sp. larvae/pupae in fruit studies have been completed on most gall-forming Allorho- To assess abundance and distribution of Allorhogas sp. gas spp., early taxonomic evaluation suggests that they rep- and Apion sp. in fruits of M. calvescens, five fruiting inflo- resent a highly diverse group with each species being quite rescences were collected at random from each of 10 ran- host specific (Hanson, personal comment). Gall formers domly selected trees at each site. Inflorescences were are considered relatively successful biological control agents brought to the laboratory where 10 fruits were randomly of weeds because of their impact on plant development (galls selected from each inflorescence for dissection and exami- act as resource sinks) and reproduction as well as their host nation with a stereomicroscope. The number of larvae specificity (Dennill et al., 1999; Harris and Shorthouse, and pupae of Allorhogas sp. and Apion sp. in each fruit 1996; Hoffmann et al., 2002; Julien and Griffiths, 1998; was recorded. Presence of an undescribed eulophid parasit- Meyer, 1987; Morris, 1999; Weiss et al., 1988). oid (Hymenopetera: Eulophidae: Tetrastichinae) attacking The main objectives of this research were to study abun- Allorhogas sp. also was recorded. Fruits were sampled on dance and within-tree dispersion of Allorhogas sp. and 21–23 August 2006 at the three field sites. On 14 September Apion sp. on M. calvescens in their native habitat in Brazil 2006, fruit sampling was repeated at the Vic¸osa site, where and to determine their effect on M. calvescens fruit size and fruit development lagged behind the other sites, probably seed set. We hypothesize that these species may have a due to lower temperatures in Vic¸osa. At the time of sam- significant impact in reducing seed set in M. calvescens,in pling, each inflorescence was assigned to one of four phe- which case they would deserve further attention as poten- nological categories: <25%, 25–50%, 50–75%, and >75% tial biological control agents. mature (red or purple) fruit. 2. Materials and methods 2.3. Impact of Allorhogas and Apion sp. on fruit 2.1. Study sites To quantify the effect of Allorhogas sp., fruit diameter and the number of seeds per fruit were determined in a This study was conducted in three different locations in total of 40 fruits (including fruits infested and non-infested the native habitat of M.