Effect of ant predation and abiotic factors on the mortality of medfly larvae,Ceratitis capitata,in the Argan forest of Western Morocco

The Argan Argania spinosa (L.) Skeels (Ericales: Sapotaceae) is an endemic and emblematic tree growing in the centre and the southwest of Morocco. Argan fruits are frequently infested by the Mediterranean fruit fly Ceratitis capitata Wied (Diptera: Tephritidae). To date, no control program has been undertaken in the Argan forest. This research is the first investigation of natural mortality factors of C. capitata larvae in the Argan forest. The study was conducted at two localities near the city of Essaouira with different climatic conditions. Observations were conducted using 260 late instar larvae which were individually deposited on the ground, under fruiting host trees, where they naturally fall to find a suitable pupation site. Overall, 42% of the larvae died before being able to burrow into the ground, irrespectively of the location. Larval survival and their likelihood of burrowing decreased with increasing ground temperature, as 53% of all the larvae deaths occurred at temperatures over 48°C. However, at lower ground temperature, predation by ants and spiders accounted for 47% of all mortality. Four species of ants carried out 94% of the captures. Monomorium subopacum Mayr (Hymenoptera: Formicidae), which frequently forages under Argan trees, was by far the most efficient predator, due to a powerful sting that rapidly immobilizes the prey. Our results suggest that the burrowing performance of larvae is constrained by high thermal conditions and the presence of ant predators at lower temperatures.     

Effect of inhibiting prostaglandin synthesis on edema formation and albumin leakage during thermal trauma in the rat

Prostaglandins (PGs) participate in the inflammatory response, but the contribution of endogenously synthesized PGs to edema formation and increased vascular permeability is not known. Using a 10% scald burn in the rat, we measured water content (as percent, wet minus dry/wet weight) and 131I-RISA leakage (counts/g dry tissue) in scalded and normal skin at 30 minutes and 3 hr post injury. Four groups (10 rats/group) in each time period studied: control; scald; scald, 5 mg/kg indomethacin; scald, 10 mg/kg indomethacin. Indomethacin was administered intravenously 30 minutes before the scald; RISA was injected intravenously 30 min before termination of the study. In all indomethacin-treated groups immunoreactive plasma PGA was significantly lower (p less than 0.05) than in scalded, untreated groups. All scalded groups showed significantly higher RISA counts and water content than did the control group (p less than 0.01). At 30 min post-injury the indomethacin -treated groups did not differ from the untreated scald group (p greater than 0.20). In the 3 hour study all scalded groups had significantly higher content and RISA counts than control (p less than 0.01). Thus PGs produced during thermal trauma do not greatly contribute to the edema formation and increase in vascular permeability.