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ThesisItem Open Access NEUROENDOCRINE REGULATION OF LIPID METABOLISM IN Periplaneta americana(AAU, Jorhat, 2017-07) Borah, Nirmali; Hazarika, L. K.The present investigation on Neuroendocrine regulation of lipid metabolism in Periplaneta americana was conducted during 2013-2017 in the Physiology laboratory of Department of Entomology, Assam Agricultural University, Jorhat. A total of six instars were recorded during the biology study of P. americana. The pre oviposition period, incubation period, nymphal period, adult longevity and total life cycle period of P. americana during the present investigation were 8.4±1.40, 40.66±4.43, 326.83±76.30, 272.76±57.40 and 367.50±74.95 days, respectively. The duration of each nymphal instar from first to last were 40.70±4.41, 44.96±2.66, 56.20±1.16, 58.60±1.28, 61.11±3.44 and 65.26±1.47 days, respectively. The mean ootheca length, width and weight recorded were 10.53±1.48 mm, 5.23±0.45 mm and 125.73±16.35 mg, respectively. The mean number of oothecae produced by a female were 13.86±1.56 with 14.93±1.89 eggs per ootheca. The number of eggs hatched per ootheca was 12.76±2.20 with a hatching percentage of 90.63±5.57 per cent. The body length of each instar increased significantly from the first (3.26±0.60 mm) to the sixth (39.33±2.04) and attained its peak in adult stage, exhibiting sexual dimorphism, the male was comparatively longer (43.30±6.38 mm) than the female (39.43±2.03 mm). The antennae length recorded from first instar to sixth instar were 5.01±0.13, 14.41±0.61, 15.17±0.30, 23.62±0.98, 25.01±0.13 and 45.02±0.25 mm, respectively. The adult male and female antennae length recorded were 50.08±1.61 and 43.03±3.85 mm. The head width from first instar to sixth instar were 1.04±0.04, 1.51±0.08, 2.59±0.32, 3.00±0.28, 4.00±0.09 and 4.02±0.08 mm, respectively. The head width of adult male and female were 5.00±0.10 and 4.11±0.18 mm. The pronotum size (length width) recorded from first instar to sixth instar were (1.06±0.06) (1.07±0.70) mm, (1.15±0.08) (1.17±0.09) mm, (3.05±0.22) (3.71±0.37) mm, (4.86±0.16) (6.94±0.19) mm, (6.92±0.11) (8.87±0.15) mm, (7.96±0.06) (9.03±0.10) mm respectively. The pronotum size (length width) of adult male and female were (9.45±0.57) (10.96±0.71) and (9.14±0.46) (10.80±0.71) mm, respectively. A positive and significant correlation was observed between female weight and ootheca number (r = 0.743) and weight (r = 0.747). The weight of males increased after adult ecdysis till first mating on day 5 (1.11±0.03 g), and then decreased to day 30 (0.87±0.03 g) after emergence, then again increased from day 40 onwards, however, subsequently it maintained fairly a constant weight (1.22±0.11 g). The weight of females began to increase steadily during its adulthood (1.27±0.04 g) and peaked (1.40±0.08 g) on day 30. The highest weight was recorded on day 75 (1.43±0.07 g). A decrease in body weight was observed on day 80 (1.32±0.15 g) and day 85 (1.31±0.06 g), which were coincide with ootheca deposition. The lipid content of the adult male P. americana increased from day 1 (103.70±0.67 mg) to day 50 (281.93±1.94 mg) and reached its peak on day 65 (283.40±2.72 mg) after which it starts declining. The lipid content of the older males stayed fairly constant. The lipid content of adult female increased significantly in a similar trend with that of male and reached peak from day 60 (326.66±1.25 mg) to day 70 (326.23±1.11 mg) after that it remained fairly constant. A significant drop in the lipid content was observed on day 80 (217.16±2.98 mg). The correlation study revealed that the body weight was positively correlated with lipid content (mg) of both male and female P. americana. The exposure of adults to growth hormones suppressed adult emergence and caused morphological abnormalities producing either nymphoids or giant nymphs and adultoids. Among the different concentration of growth hormones tested 5 ppm methoprene and 5 ppm JH III were found to be effective in lowering the body weight and lipid content of P. americana when applied either topically or by injection. An adult male and female P. americana imbibed 62.66±7.18 ml and 66.33±8.32 ml of water per day when they were deprived of water for 24 hours, but after 48 hours of starvation water consumption was 70.63±9.44 and 80.07±9.51 ml per day for adult male and female, the latter were significantly higher than the former. Very low impact was observed at short deprivation periods and it was observed that all the females died before the longest deprivation period ended. The hatching percentage was found to be less in case of the ootheca produced by the deprived female than that produced by a normal female P. americana.