Biologia 65/5: 899—902, 2010 Section Zoology DOI: 10.2478/s11756-010-0097-4
Developmental rates of the aphid Aphis pomi (Aphidoidea: Aphididae) and its parasitoid Aphidius ervi (Hymenoptera: Aphidiidae)
Radovan Malina1,JánPraslička2 &JankaSchlarmannová2
1Department of Biology & Ecology, Faculty of Natural Sciences, Matej Bel University, Tajovského 40,SK-97401 Banská Bystrica, Slovakia; e-mail: [email protected] 2Department of Zoology and Anthropology, Faculty of Natural Sciences, Constantine the Philosopher University, Nábrežie mládeže 91,SK-9497 Nitra, Slovakia
Abstract: Developmental rates of the aphid Aphis pomi and its parasitoid Aphidius ervi were compared at four constant temperatures (15, 20, 25, 30 ◦C). Aphis pomi required 159.07 degree-days (DD) above lover developmental threshold (LDT) of 0.3 ◦C. Aphidius ervi required 229.73 DD above LDT of 5.98 ◦C. Developmental rate of A. pomi is higher than the developmental rate of A. ervi at the same conditions. Key words: apple aphid; parasitoid; degree day; lover developmental threshold
Introduction development in various environments, including stored products, greenhouses and orchards (Subramanyam et Aphidius ervi Haliday, 1834 (Hymenoptera: Aphidi- al. 1990; Graf et al. 1996; Kindlmann & Dixon 1999; idae) is a cosmopolitan, solitary, endophagous para- Dixon 2000). sitoid (Marsh 1977) and a major biological control The effect of temperature on the development, per- agent of several aphid species damaging economically centage of parasitism and longevity of A. ervi reared on important crops such as legumes and cereals (Powell A. pomi have been studies recently (Malina & Praslička 1982; Starý et al. 1988). The impact of a parasitoid 2008). However, developmental rates of the host A. on its host population greatly depends upon its ability pomi have not been investigated in detail. Therefore to find and parasitize hosts and to increase offspring we carried out a study with the aim to compare the numbers in response to increasing host density (Waage development rates of A. ervi and A. pomi and evaluate & Hassell 1982; Mackauer 1983). That’s why an effec- the potential of A. ervi as a biological control agent of tive parasitoid should develop very quickly. Braconid A. pomi. species of the subfamily Aphidiidae have rapid larval development and short preoviposition intervals, giving Material and methods minimum life cycles of 10 to 15 days (Danks 2006). Sev- eral authors (Sigsgaard 2000; Deng & Tsai 1998; Bueno & van Cleave 1997; Miller & Gerth 1994; Tripathi & Aphid source Padney 1994) have studied temperature-dependent du- Aphis pomi colonies used in this study were initiated by a single collection of wild aphids from the apple trees in Ban- ration of parasitoid development. ◦ ◦ Aphis pomi ská Bystrica city (Slovakia, 48 44 N, 19 08 E) in April The green apple aphid, deGeer, 1773 2006. The colonies were maintained on fresh apple tree is a common inhabitant of apple orchards. Dense popu- shoots (replaced every two days after all aphids migrated lations may cause abnormal growth of terminal shoots, from dry to fresh shots) in a thermostat at 25 ± 1 ◦C, 60 ± reduce the percentages of non-structural carbohydrates 5% RH and a photoperiod of 16:8 (L:D) hours. After one- in shoots, roots and leaves of apple trees and reduce the month rearing period, the ensuing colonies were used for crop (Kaakeh et al. 1993). Arbab et al. (2006) modelled experiments. the development period of A. pomi at six constant tem- peratures. Parasitoid source Aphidius ervi were obtained by a single collection of aphid The knowledge of thermal constants and lower de- mummies from apple trees in Banská Bystrica city in May velopment thresholds provide essential information to 2006. Mummies were kept individually in small glass vials determine the development rate of a particular species (5 × 1.5 cm) under the same temperature and humidity of arthropod (Jarošík et al. 2002). Thermal constants conditions as the aphids. Mummies were checked daily and are frequently used to create predictive models of pest adults retrieved as they hatched.