Effects Of Sodium Dificiency On Physiology And Behaviour In The Cotton Boll Worm, Helicoverpa Armigera (Lepidoptera: Noctuidae)

The adults of many species in Lepidoptera were found visiting moist ground, perspiration, tears, excrements, rotten carcases. This behaviour called'puddling' or 'mud-puddling'. One of the goals of puddling behaviour is to intake sodium. In present paper, H. armigera larvae were allowed to feed on one of three different artificial diets, that is, a normal (A), a sodium-deficient (B) and an extremely sodium-deficient (C) artificial diet, and the effects of sodium dificiency on physiology and behaviour were evaluated.1. Effects of diet on growth of the larvaeThe H. armigera larvae on three diffient artifical diets could develop normally. There was no difference in pupation percents and pupa weights. The larvae on diet C grew faster, had a significantly shorter development period than those on diet A and B.2. Effects of larval diet on the adultsThe emergence rate of the adults from on diet A, B and C was similar, but the wing shape of the moths from diet B and C tended to abnormal. Moreover, the mean weights of both males and females from diet A were significantly greater than those from diet B and C.3. Effects of larval diet on flight capacity in adultsMoths from diet A and B flied more rapidly and covered longer distances than those from diet C, with similar sugar and lipid utilization rates among three test groups.4. Effects of larval diets on larvae cannibalismWhen the larvae previously fed on diet A or diet C were transferred respectively to diet A or diet C at the 4th instar, those on diet A ingested significantly less amount of food. It seems that the larvae suffering from sodium shortage may increase food intake to obtain more sodium. When the larvae were restricted to diet A, B or C, the survival rate from the 1st to the 3rd instar was 85.6,70.4 and 65.6%, respectively, with the former significantly greater than latter. When a cannibal from diet A, B or C and a victim from diet A were housed together for 1 hour, much more cannibals from diet C ate their victims, in contrast to the cannibals from diet A and B. When a victim from diet A, B or C was provided, a cannibal from diet C preferred to eat the victim from diet A.5. Effects of larval diets on sodium intake by adultsThe sodium intake of the one-day-old moths was determined by giving unlimited access to a O.OOlmol/L sodium solution. One day later, the average weight increase for 10 males from diet A, B or C was -2.7%±0.2%,3.1%±0.6% or 10.7%±0.3%, respectively. The latter was significantly higher than the former two. Meanwhile, the weight increase for 10 females from diet A, B or C was -0.04%±0.1%,10.8%±0.3% or 10.1%±0.4%, respectively. The latter two were significantly higher than the former.