Combined Effects of Heat Stress and Food Supply on Flight Performance of Olive Fruit Fly (Diptera: Tephritidae)

Abstract

The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is a newly invasive pest of olives, Olea europaea L., in California. The table olive industry is located in California's Central Valley, where daily high summer temperatures can be >35.0°C. This study investigated the effects of high temperatures (heat stress) and food conditions on the flight performance of B. oleae in laboratory flight mill tests. Flies were provided food (honey and hydrolyzed yeast) and water for a 1-wk preconditioning period and then subjected to 24-h preflight exposure to diurnal temperature regimes (low-high temperatures of 18.3–35.0°C and 18–37.8°C) and deprivation of food. Flies with the preflight stress conditions had significantly lower flight performance (1,305 m and 0.989 h at 18.3–35.0°C and 1,152 m and 0.966 h at 18.3–37.8°C) than control files that were held under no-stress preflight conditions (constant 23.9°C, food, and water) and flew 1,982 m for 1.54 h. Flight distance and duration were further reduced when no water was provided during the 24-h preflight exposure to high temperature stress. Flight distance and duration also were decreased when the preflight exposure period was increased to 2 and 3 d. When flies were deprived of food and water during the preconditioning period, there was significant adult mortality and flight performance was poor (<50 m and <2 min) after 24-h preflight exposure to either the 18.3–35.0°C or the 18.3–37.8°C temperature regime and deprivation of food. Heat stress and food deprivation also reduced postflight fecundity and adult longevity. The results are discussed with respect to the ability of B. oleae to survive summer heat and food deprivation by dispersing to refuges with food, water, and shelter.

Comparative evaluation of two olive fruit fly parasitoids under varying abiotic conditions

“…High density B. oleae populations occur in California's coastal olive regions while population density and crop infestation is generally lower in the interior valleys ) where high summer temperatures may limit population growth Wang et al 2009a). Studies of indigenous natural enemies in California found that B. oleae larvae are attacked by Pteromalus sp.…”

“…Relative to climate, olives are grown in California's coastal regions that are characterized by mild temperatures and in interior valleys that are characterized by hot, dry summers. In the warmer interior valleys, fly population growth may be limited during periods of high summer temperature , which increases adult fly mortality and reduces their movement and oviposition success (Wang et al 2009a). This might also impact parasitoid establishment and effectiveness in California via direct mortality of Psyttalia as developing larvae or as foraging adults Sime et al 2006a;Yokoyama et al 2010).…”

Biological controls investigated to aid management of olive fruit fly in California

“…The olive fruit fly's survival is limited in regions with high or low temperature extremes (Wang, Johnson, Daane, Opp 2009). The fruit also may not be developed enough for olive fruit fly to survive early in the summer; young, hard fruit are not preferred for oviposition (Burrack and Zalom 2008).…”

High temperature affects olive fruit fly populations in California's Central Valley

“…Using a customdesigned flight mill, Wang et al (2009b) reported that adults of both sexes held for 7 days at 75°F (constant temperature) and provided with ample food (honey and hydrolyzed yeast) and water, were able to fly uninterrupted for an average of 2,164.8 ± 228.8 yards during a mean period of 1.54 ± 0.16 hours ( fig. 3).…”

“…Without food or water immediately available, an adult will only be able to fly an average of 16.4 ± 4.4 yards to locate these resources in a dry and unexplored landscape. Such a fl y would have an 84% chance of dying in the fi rst 24 hours, and of those that did survive only about 25% would be able to fl y (Wang et al 2009b). Additionally, when olive fruit fl y adults were held at 65°F at night and 95°F or 100°F during the day over a 3-day period with either water alone or no food or water, those fl ies that survived one day could fl y signifi cantly farther than those that survived 3 days (F 2,407 = 18.7, P < 0.01) (fi g. 4).…”