Biological Control 36 (2006) 189–196 www.elsevier.com/locate/ybcon Effect of temperature on life history of Quadrastichus haitiensis (Hymenoptera: Eulophidae), an endoparasitoid of Diaprepes abbreviatus (Coleoptera: Curculionidae) J. Castillo a, J.A. Jacas b,*, J.E. Pen˜a a, B.J. Ulmer a, D.G. Hall c a University of Florida/IFAS, 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 c USDA, USRHL, Fort Pierce, FL 34945, USA Received 9 May 2005; accepted 26 September 2005 Available online 13 December 2005 Abstract The influence of temperature on life history traits of the egg parasitoid Quadrastichus haitiensis (Gahan) (Hymenoptera: Eulophidae) was investigated in the laboratory on eggs of the root weevil Diaprepes abbreviatus (L.) (Coleoptera: Curculionidae). Duration of devel- opment from egg to adult decreased from 39.99 ± 0.27 days to 13.57 ± 0.07 days (mean ± SE) as temperature increased from 20 to 33 °C, respectively. No development was observed at 5–15 °C. Fecundity was highest at 25 and 30 °C (70–73 eggs per female) but was reduced at 33 °C (21.5 eggs per female). Oviposition rate was also reduced at 33 °C. Q. haitiensis accepted host eggs from 0 to 7 days old for oviposition but was most prolific when parasitizing 1- to 4-day-old eggs. Very few adult Q. haitiensis emerged from host eggs that were 5–7 days old, however, D. abbreviatus egg mortality was similar for eggs 0–7 days old. A brief description of the parasitoid egg, larva, prepupae, and pupa is provided. Ó 2005 Elsevier Inc. All rights reserved. Keywords: Parasitoid; Eulophidae; Life cycle; Reproductive development 1. Introduction concealed sites, usually between two adjacent leaves that are sealed together with a gelatinous cement secreted dur- The Diaprepes root weevil, Diaprepes abbreviatus L., is a ing oviposition (Browning et al., 1995). Curculionidae endemic to the Caribbean islands that was Considerable research in Florida has been directed first detected in Florida during the 1960s (McCoy and toward developing management strategies for D. abbreviatus Simpson, 1994; Woodruff, 1968). This weevil is a highly (McCoy, 1985; McCoy and Simpson, 1994). Efforts to polyphagous species (Grafton-Cardwell et al., 2004; Simp- establish biological control by parasitoids began during the son et al., 1996) and currently a pest of major importance 1970s with releases of the endoparasitoid Quadrastichus in Florida citrus and certain ornamental and root crops (Tetrastichus) haitiensis (Gahan) (Hymenoptera: Eulophi- (Mannion et al., 2003; McCoy, 1985; McCoy and Simpson, dae) (Beavers et al., 1980; Sutton et al., 1972). Q. haitiensis 1994; Simpson et al., 1996). Adult weevils feed on young, failed to establish (Beavers and Selhime, 1975; Hall et al., tender foliage, and heavy infestations can completely defo- 2001) at that time, but efforts to establish the parasitoid were liate young trees. Larvae feed underground, causing severe reinitiated in 1997 (Pen˜a et al., 2005). Q. haitiensis was orig- damage to root systems. Mated females lay egg masses in inally described from specimens reared from eggs of Exop- thalmus quadrivitattus Schauff (Coleoptera: Curculionidae) from Port-au-Prince, Haiti (Schauff, 1987). It is a primary * Corresponding author. Fax: +34 964 728066. egg parasitoid that has been reared from D. abbreviatus E-mail address: [email protected] (J.A. Jacas). and Pachnaeus litus (Germar) (Coleoptera: Curculionidae) 1049-9644/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.biocontrol.2005.09.023 190 J. Castillo et al. / Biological Control 36 (2006) 189–196 (Armstrong, 1987; Schauff, 1987). According to Van Wher- were offered in a choice situation to 250 2- to 3-day-old vin (1968), it is also the most common parasitoid of citrus pairs of Q. haitiensis. Parasitoids were introduced into a weevil eggs in Jamaica and at times may parasitize up to Plexiglas cage (as described above). The parasitoids were 100% of the weevil egg masses in local areas. The parasitoid provided pure honey (streaked on paper placed on the has also been collected from the Dominican Republic, Puer- inside wall of the cage) and water (dispensed through a sat- to Rico, Andros Island, and Cuba (Schauff, 1987). During urated cotton wick in a vial placed on the bottom of the 1998, the parasitoid was collected in Puerto Rico from cage). Branches with leaves containing D. abbreviatus eggs Diaprepes spp. eggs (Pen˜a et al., 2005). Subsequently, releas- were inserted into a 100 ml plastic container filled with es of Q. haitiensis were made beginning in 2000 into citrus water and placed in the center of the cage. The wax paper and ornamental fields in Florida. The parasitoid is now strips with eggs were randomly hung from the cage wall. established in southern Florida (Miami-Dade County) in Host eggs were removed from the cage 1 day later and indi- open-field ornamental plant nurseries, but it has failed to vidually dissected under a microscope to assess presence or establish elsewhere (Pen˜a et al., 2005). Clues to determining absence of parasitoid eggs. Data were subjected to one-way why the parasitoid failed to establish in other geographical analysis of variance and t test was used for mean separa- areas in Florida may be gained from knowledge of the tion at P < 0.05 (STSC, 1987). biology and life cycle of the parasitoid, information that is presently lacking. The objective of the investigations report- 2.4. Influence of host egg age on parasitism ed here was to determine the effect of temperature on the life history of Q. haitiensis under controlled laboratory A no choice test was conducted to investigate the influence conditions, as a means of evaluating the suitability of this of host egg age on parasitism. D. abbreviatus eggs that were 1, parasitoid as a biocontrol agent of D. abbreviatus in Florida. 2, 3, 4, 5, 6, and 7 days old were exposed to Q. haitiensis adults. Six D. abbreviatus egg masses of the same age group 2. Materials and methods (non-concealed on wax paper) were offered to 30 female and 10 male Q. haitiensis adults (1–5 days old) for 16 h. The Stock colonies of both D. abbreviatus and Q. haitiensis experiment was conducted in Bell 1-L wide mouth jars, the were held in a room maintained at 26.5 ± 1 °C, 12:12 lids had a 7-cm-diameter opening covered with fine mesh L:D, and approximately 78% RH. Unless otherwise stated, to allow ventilation. Each jar was supplied with a moist cot- the same environmental conditions applied to the assays. ton wick and a smear of honey. After 16 h all Q. haitiensis adults were removed and each individual egg mass was 2.1. Rearing of Diaprepes abbreviatus placed in a 10 ml test tube. The open end of the test tube was covered with a 2-ply Kimwipes tissue to allow ventila- Colonies of Diaprepes root weevils were obtained from tion. The number of host eggs per egg mass, the number ornamental fields near Homestead, FL (80.2°W long., and sex of the emerging parasitoids, and the number of dead 25.3°N lat., 1 m alt.). Weevils were placed in 30 · 30 · D. abbreviatus eggs were recorded. The experiment was rep- 30 cm Plexiglas cages with water and foliage of Conocarpus licated five times for each host egg age. Data were subjected erectus L. (Myrtales: Combretaceae) which provided a food to a Kruskal–Wallis ANOVA which allowed the detection of source and an oviposition substrate. Wax paper strips significant differences between the means (P < 0.05) (Statis- (3 · 10 cm) stapled together were also used as an oviposition tix 8 Analytical Software, 2003). substrate as described by E´ tienne et al. (1990). When pierced by the femaleÕs ovipositor a distinct visible mark can be seen on the host egg after approximately 24 h. 2.2. Rearing of Quadrastichus haitiensis To examine the relationship between parasitoid ovipositor insertions and oviposition on different ages of host eggs, A colony of Q. haitiensis was initiated in Homestead two D. abbreviatus egg masses were offered to 10 female from a colony maintained at the Florida Department of and 3 male adult Q. haitiensis for 16 h as above. Two Agriculture and Consumer Services, Gainesville, FL. days after initial exposure to Q. haitiensis individual Voucher specimens of Q. haitiensis were retained by the D. abbreviatus eggs were examined for ovipositor insertion Department of Agriculture, Gainesville, FL. marks. The experiment was repeated three times. Results were subjected to one-way analysis of variance and t test 2.3. Assessment of oviposition substrates was used for mean separation at P < 0.05 (STSC, 1987). Additionally, 10 marked eggs from each age of D. abbrevi- To establish the oviposition substrate for our assays, a atus egg mass were dissected to determine if oviposition preliminary trial was conducted to determine if there was had taken place. any difference in parasitism when Q. haitiensis was offered 1-day-old D. abbreviatus egg masses either concealed 2.5. Assessment of development and biometrics between C. erectus leaves, concealed between wax paper strips or non-concealed in wax paper strips (one strip Five hundred adult parasitoids 1–7 days old, which were removed). Seventeen weevil egg masses of each treatment provided water and a dab of honey, were released into a J. Castillo et al. / Biological Control 36 (2006) 189–196 191 Plexiglas cage similar to the ones described above. One oviposited weevil egg masses were offered daily to each pair hundred and eighty egg masses (less than 24-h old) contain- of parasitoids until the female parasitoid died.