The effects of hypertrehalosaemic octapeptides (peptides from AKH family) on transcription and trehalosegenesis in the fat body of adult females of Tenebrio molitor L. were examined. A synthetic hypertrehalosaemic peptide from CC of Periplaneta americana periplanetin CC-2 (Pea-CAH-II) Glp-Leu-Thr-Phe-Thr-Pro-Asn-Trp-amide (1), its new synthetic analogues Glp-Leu-Thr-Phe-Thr-Pro-Asn-Phe-amide (2), Glp-Leu-Thr-Phe-Thr-Pro-Asn-D-Trp-amide (3), Glp-Leu-Thr-Phe-Thr-Pro-Asn-D-Phe-amide (4), and an octapeptide from T. molitor Glp-Leu-Asn-Phe-Ser-Pro-Asn-Trp-amide (Tem-HrTH) (5) were tested. Peptides 2, 3 and 5 suppress transcription in the fat body tissue measured as incorporation of [3H]-uridine into total RNA. The rate of RNA inhibition in the tissue depends on the peptide concentration. Periplanetin CC-2 (2) was inactive in this test. Endogenic T. molitor octapeptide (5) stimulates trehalose release from the fat body of females, whereas Pea-CAH-II analogues (2-4) do not increase trehalose release from this tissue.
Setothosea asigna van Eecke is a dominant defoliator pest in oil palm plantations. To control this pest, a generalist predatory bug, Sycanus annulicornis Dohrn, was used as it is easy to rear on several different species of prey. In this study, we evaluated the influence of different prey on the biology and the ability of S. annulicornis to attack and kill the nettle caterpillar pest S. asigna. Based on laboratory rearing, the larvae of Crocidolomia pavonana F. (Lepidoptera: Crambidae) is a suitable prey for both the growth and development of S. annulicornis, as its nymphal development is shorter (74.0 ± 7.3 days) and adult longevity longer (81.0 ± 9.0 days for male and 64.8 ± 12.4 days for female, respectively) than when reared on the larvae of Tenebrio molitor L. (Coleoptera: Tenebrionidae) (44.0 ± 16.7 days for male and 52.6 ± 14.4 days for female). However, S. annulicornis reared on T. molitor larvae attacked 2.0-2.2 larvae of S. asigna per day, which is more than the 1.6-1.7 larvae per day of those reared on C. pavonana, which indicates that the larvae of T. molitor are a more effective diet for rearing S. annulicornis as biocontrol agent for the S. asigna., Abdul Sahid, Wahyu D. Natawigena, Hersanti, Sudarjat., and Obsahuje bibliografii
The aim of this study was to show that the kind of AKH-mobilized energy substrates in insects can be predicted on the basis of the results obtained with the application of heterologous, i.e. inter-species, AKHs. Four different AKHs, the Locmi-AKH-I inducing hyperlipaemia and hyperglycaemia in Locusta migratoria, Tenmo-HrTH inducing hyperglycaemia in Tenebrio molitor, and Pyrap-AKH and Peram-CAH-II inducing hyperlipaemia in Pyrrhocoris apterus were used, firstly in conspecific tests, secondly in all possible species-AKH combinations, and finally in individual applications on the test species, the cotton bug Dysdercus cingulatus. Since each of the AKHs induced hyperlipaemia in D. cingulatus adults, we predicted that lipids are the only energy substrates which are mobilized in this species by its native AKH. The accuracy of this prediction was subsequently confirmed by the structural identification of the native D. cingulatus AKH and conspecific application tests. The proposed methodical approach can serve as a suitable monitoring system for determination of the kind of energy substrates mobilized by native insect AKHs until the structure of the hormone is identified.