Effect of temperature on life history of Aprostocetus vaquitarum (Hymenoptera: Eulophidae), an egg parasitoid of Diaprepes abbreviatus (Coleoptera: Curculionidae) B.J. Ulmer a, * , J.A. Jacas b , J.E. Pen ˜a a , R.E. Duncan a , J. Castillo a a University of Florida, Department of Entomology and Nematology, Tropical Research and Education Center, 18905 SW 280th Street, Homestead, FL 33031, USA b Departament de Cie `ncies Experimentals; Universitat Jaume I; Campus del Riu Sec; E-12071—Castello ´ de la Plana, Spain Received 14 November 2005; accepted 7 March 2006 Available online 21 April 2006 Abstract The effect of temperatures ranging from 5 to 40 °C on Aprostocetus vaquitarum Wolcott (Hymenoptera: Eulophidae) oviposition and development were investigated. There were significant differences in the rate of development among the temperatures for all life stages. The egg stage lasted approximately 7 times longer at 15 than at 25 or 30 °C and the larval stage, consisting of 4 instars, took significantly less time at each increasing temperature from 15 to 30 °C. A. vaquitarum development from egg to adult took 16.3 days at 30 °C, sig- nificantly faster than the other temperatures tested. At 15 °C A. vaquitarum reached the pupal stage after a mean of 41.6 days but did not successfully complete pupation. A. vaquitarum eggs hatched on 66% of the parasitized egg masses at 35 °C but did not survive past the first instar. A. vaquitarum did not develop past the egg stage at 5 or 40 °C. Host Diaprepes abbreviatus L. (Coleoptera: Curcu- lionidae) eggs also did not survive at temperatures of 35 and 40 °C on live plants. Upper and lower temperature thresholds for A. vaq- uitarum development were calculated to be 33.0 and 16.0 °C, respectively. Maximum development rate occurred at 30.9 °C and a thermal constant of 494.2 DD was calculated. Photoperiods ranging from 10L:14D to 16L:8D did not significantly affect development time from egg to adult at 25 °C. Oviposition was significantly higher at 30 °C than at the other temperatures tested; oviposition was also relatively high at 25 and 35 °C and several eggs were laid at 20 °C. Relatively cool winter temperatures in central Florida may be contributing to the limited range of A. vaquitarum in the state. Ó 2006 Elsevier Inc. All rights reserved. Keywords: Diaprepes abbreviatus; Aprostocetus vaquitarum; Biological control; Citrus IPM; Development; Oviposition 1. Introduction Diaprepes abbreviatus (L.) is a root weevil native to the Lesser Antilles of the Caribbean (Woodruff, 1985). First reported in Florida in 1964, it was presumably introduced from Puerto Rico and is now established across the citrus- producing regions of the state (Woodruff, 1964). D. abbre- viatus is polyphagous and has been associated with more than 270 species of plants from 59 families (Simpson et al., 1996). Citrus and various woody ornamentals support the entire life cycle of D. abbreviatus (Mannion et al., 2003; Schroeder et al., 1979), which has resulted in a significant pest for both ornamental growers and the citrus industry where it is estimated to cost producers over 70 million dollars annually (Stanley, 1996). Adult weevils feed along the edges of leaves, leaving characteristic semi- circular notches. Eggs are laid in the canopy, glued between two leaves. Upon hatching, larvae fall to the ground to enter the soil to feed on the roots of host plants. Damage from root feeding can be significant, leading to reduced productivity and possibly death of the host plant. Root feeding may also leave citrus plants more susceptible to 1049-9644/$ - see front matter Ó 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.biocontrol.2006.03.002 * Corresponding author. Fax: +1 217 863 2763. E-mail address: bryan_james.ulmer@syngenta.com (B.J. Ulmer). www.elsevier.com/locate/ybcon Biological Control 39 (2006) 19–25