Effect of temperature on the developmental rate, longevity and parasitism of Aphidius ervi Haliday (Hymenoptera: Aphidiidae)

Abstract

Malina R., Praslička J. (2008): Effect of temperature on the developmental rate, longevity and parasitism of Aphidius ervi Haliday (Hymenoptera: Aphidiidae). Plant Protect. Sci., 44: 19-24.Temperature-dependent development, longevity and parasitism of the parasitoid Aphidius ervi Haliday was measured at four constant temperatures between 15°C and 30°C using Aphis pomi de Geer as host. The thresholds for egg-mummy and mummy-adult development were 6.8°C and 3.9°C, respectively. Development into mummies required an average of 146.3 degree-days (DD), while development into adults took an average of 85.3 DD. Longevity was increasing linearly in the range from 15°C to 25°C (8-15 days), but was lower at 30°C (11 days). The relationship between parasitism, recorded as percent aphids mummified, and temperature was increasing at the temperatures 15-25°C, but decreasing at higher temperatures; 10.8% of the aphids were parasitised at 15°C, 15.9% at 25°C and 14.6% at 30°C. These results are compared with previously reported data on temperature-dependent development of A. ervi on a different host.Keywords: Aphidius ervi; development time; parasitism; longevity; thermal constants 20 Vol. 44, Plant Protect. Sci. Ohta & Ohtaishi (2003) have reported also the temperature-dependent longevity of Aphidius gifuensis Ashmead. The apple aphid, Aphis pomi de Geer, is a common inhabitant of apple orchards. Dense populations may cause abnormal growth of terminal shoots, reduce the levels of non-structural carbohydrates in shoots, roots and leaves and lower the yield of fruit (Kaakeh et al. 1993).The knowledge of thermal constants and lower development thresholds provides essential information to determine the development rate of a particular species of arthropod (Jarošík et al. 2002). Thermal constants are frequently used to create predictive models of pest development in various environments, including stored products (Subramanyam et al. 1990), greenhouses and orchards (Graf et al. 1996).We studied the effect of temperature on the development, percentage of parasitism and longevity of Aphidius ervi at four constant temperatures to evaluate its potential as a biological agent to control Aphis pomi. MATERiAL AnD METhoDsHost aphid source. Aphis pomi colonies used in this study originated from a single collection of wild aphids from apple trees in the town Banská Bystrica (48°44'N, 19°08'E) in April 2006. The colonies were maintained on fresh apple tree shoots (replaced every 2 days after all aphids had migrated from dry to fresh shots) in a thermostat at 25 ± 1°C, 60 ± 5% RH and a photoperiod of 16:8 (L:D) hours. After a 1-month rearing period, the colonies were used for parasitoid experiments.Parasitoid source. Aphidius ervi were obtained from a single collection of aphid mummies from apple trees in the town Banská Bystrica in May 2006. Mummies were kept individually in small glass vials (5 × 1.5 cm) under the same temperature and humidity conditions as aphids. Mummies were checked daily and parasitoid adults retrieved as they hatc...

Facultative bacterial endosymbionts shape parasitoid food webs in natural host populations: A correlative analysis

“…Our study identifies parasitoid species which might differ in specific traits regarding their susceptibility to certain facultative endosymbiont species. For example, the fecundity of the facultative endosymbiont‐“tolerant” parasitoids E. plagiator (~160–250 eggs) and A. rhopalosiphi (~200 eggs) is lower compared to other parasitoids in our study such as Aphidius uzbekistanicus (~500 eggs), Aphidius matricariae (~300 eggs) and Praon volucre (~350–500 eggs; Hagvar & Hofsvang, ; Lins, Bueno, Silva, Sampaio, & van Lenteren, ), whereas the longevities of the “tolerant” parasitoids E. plagiator (~15–25 days), A. rhopalosiphi (~13 days) and A. ervi (~15 days; Azzouz, Giordanengo, Wackers, & Kaiser, ; Malina & Praslicka, ) are longer compared to other parasitoids such as A. matricariae (~7–13 days) and P. volucre (~11 days; Hagvar & Hofsvang, ; Lins et al., ). This suggests that parasitoids with higher fecundity and lower longevity are more likely to oviposit unselectively, whereas species with a lower fecundity and higher longevity are more likely to overcome endosymbiont protection or to oviposit selectively.…”

Heat Stress Affects Facultative Symbiont-Mediated Protection from a Parasitoid Wasp

“…There, parasitoid wasps are a common natural enemy [49,50], but aphids and other insects must also face a range of simultaneous threats to their survival. Temperature and precipitation can affect the strength of pathogen and predation pressures, as well as affect the insect itself [46,51]. While the host’s benefit from carrying the X-type symbiont when only one threat is encountered [18], we show here that these benefits can be rendered obsolete when two threats occur simultaneously, and even benefit the parasitoid under certain conditions.…”

“…The fitness of A . ervi reduces at higher temperatures [46] and the developing egg may have been killed outright, leading to high aphid resistance. The aphids have greater survival in this situation and thus benefit from being exposed to two stresses (parasitoids and heat after parasitoid attack) compared to parasitoid attack on its own.…”

Trans-generational effects on diapause and life-history-traits of an aphid parasitoid

“…For this purpose, parasitoids from the rearing culture were randomly assigned to different thermal conditions during their entire development (G1: 14 °C or 20 °C at 8:16 h LD) and their offspring (G2, within the parasitized aphids) were placed at 14 °C, 8:16 h LD to have lineages of different temperature history. The temperature of 20 °C does not induce diapause when associated with short photoperiod regime (Tougeron et al, 2017b) and it is different enough from 14 °C to expect differences in traits, development time and diapause incidence through maternal effects in A. ervi (Malina and Praslicka, 2008). Three climate chambers were used to randomly assign the aphid pots.…”