Browsing by Author "Quartey, S.Q."
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Item Effect of temperature on the development and predatory behaviour of culex (lutzia) tigripes (grandpre and charmoy)(Insect Science and its Application, 2000-06) Appawi, M.A.; Quartey, S.Q.To study the effect of temperature on the development and predatory behaviour of Culex (Lutzia) tigripes, immature stages of the predatory mosquito Cnlex (Lntzia) tigripes were reared at temperatures ranging from 12-37°C and provided Cnlex qiiinqnefasciatns larvae as prey. Larval developmental duration decreased with an increase in rearing temperature until an optimum temperature of 30°C was reached. Above this temperature, the. immatures developed slower. In contrast, pupal developmental duration decreased at temperatures above 30°C, being shortest at 32°C. The lower and upper threshold temperatures for larval development were around 12°C and 34°C respectively. Fourth instars were the most voracious and had the longest developmental time. The daily rate of prédation increased with temperature, with more prey larvae being consumed at 30°C. Although they consumed more prey, Cx. tigripes larvae and pupae were smaller at high temperature. The increase in prey consumption during the entire larval developmental period at 20°C was attributed to a longer larval duration at this temperature. Developmental period and growth of male and female larvae reared at a particular temperature were not significantly different. Depending on temperature, each larva consumed between 160 and 229 Cx. quinqiiefasciatiis larvae during its development. The implications of these findings to the possible use of Cx. tigripes for mosquito control are discussed. © 2000 ICIPE.Item Insects Associated with Citronella in South-Eastern Ghana, With Particular Reference To Shoot borers(University of Ghana, 1993-09) Sarfo, J.E.; Quartey, S.Q.; University of Ghana,College of Basic and Applied Sciences,School of Biological Sciences,Department of Animal Biology and Conservation Science (DABCS)Insects associated with citronella were surveyed in the south-eastern part of Ghana for 11 months. Using two different sweep nets, intensive and extensive surveys showed that the foliage of citronella was associated with a diverse insect fauna comprising 10 orders and 102 families as follows: Hymenoptera (29), Diptera (32), Homoptera (8), Hemiptera (12), Coleoptera (10), Dictyoptera (2), Orthoptera (3), Lepidoptera (2), Dermaptera (1), and Neuroptera (3). The shoot of citronella was found to be damaged by dipterous shootflies (Fam: Chloropidae and Fam: Lonchaeidae) and lepidopterous stemborers (Fam: Pyralidae and Fam: Noctuidae). There was no significant difference (P > 0.05) between the mean percentage infestation by the shootflies (mean =1.18%) and that of the stemborers (mean = 0.59%). The chloropid shootflies were identified as Scoliophthalmns micantipennis Duda, Scoliophthalmus trapezoides Becker, Anatrichus pygmaeus Loew, Aprometopis flavofacies Becker, Elachiptera occipitalis Becker, and unidentified species. The lonchaeid shootfly was Silbapectita McAlpine. The pyralid and noctuid stemborers were Eldana saccharina Walker and Sesamia sp, respectively. Whereas S. micantipennis, A. flavofacies were found to cause primary damage by attacking fresh stems, S. trapezoids caused both primary and secondary damage by attacking fresh as well as already infested stems. The status of the other chloropids and the lonchaeid was not clear, since they were always found in association with other insects in already infested tillers. The lepidopterous stemborers were also found to cause primary damage. The larvae of the stemborers attacked the lower part of the tiller and tunnelled a length of 75.40 ± 12.79 mm while the shootflies tunnelled 32.60 ± 3.90 mm. The larvae live inside the tillers and so can possibly be controlled by systemic inseticides. Preliminary field investigation showed that the worker caste of unidentified termites attacked the roots and stems of citronella, and this invariably led to complete death of the plant. This was more prevalent in farms older than one year; for example, 85.7% of the termite infested farms were older than one year. Farmers should therefore not cultivate one farmland for too long. Further investigations showed negligible symptoms of feeding activities of insect foliage pests. For example, less than 0.005%, 0.002% and 0.009%, showed necrosis, curling and defoliation respectively, from insect attack in any farm. Investigation of the seasonal variation of shootborer infestation of citronella showed two possible peaks: one between February and March, and another around October for both the lepidopterous stemborers and chloropid shootflies. The synchronisation in the build up of the damage by both groups of shootborers shows that they can be controlled simultaneously. Percentage 'deadheart' caused by lepidopterous stemborers had a weak linear relationship with rainfall: y = 0.0017x + 0.6298. That by the dipterous shootflies also had a weak linear relationship with climatic factors as follows:-rainfall: y = -0.0024x + 1.3413; evaporation: y = -0.8958x + 2.2639; temperature: y = -0.5826x + 17.15; and relative humidity: y = 0.1292x - 9.8968; where y = percentage deadheart' and x = climatic factor. Comparision of sampling, using only visual 'deadheart' symptom and random dissection, showed that using only 'deadheart' symptom underestimated the infestation of shootborers by 31.8%. Shootborer infestation should therefore be determined from random dissection of tillers. The pupa of female S. micantipennis measured 3.32 ± .08mm in length (n=30) and pupal period averaged 6.72 ± 0.39 days (n = 22). The male pupa measured 3.16 ±.07 mm long (n = 30) and the mean pupal period was 7.24 ± 0.05 days (n = 17). The adults of both sexes lived for about the same period: 8.59 ± 0.77 days (n = 29) for the female and 9.41 ± 0.60 days (n = 24) for the male. The adults exhibited sexual dimorphism with respect to their total body lengths, the male being shorter (1.90 ± 0.02mm; n = 30) than the female (2.98 ± 0.03mm; n = 31).Item Studies on the feeding behaviour of larvae of the predaceous mosquito culex (LUTZIA) tigripes grandpre and chamoy (üIPTERA: CULICIDAE)(Insect Science and its Application, 2000-12) Appawu, M.A.; Dadzie, S.K.; Quartey, S.Q.Experiments were carried out to determine the factors that influence the feeding behaviour of Cnkx tigripes, a mosquito whose larvae are predators of other mosquito larvae. The results indicated that the efficiency of predatory activities of Cx tigripes larvae increased as they developed from 1st to 4th instar with regard to the number of mosquito prey larvae they consumed in a given period of time. Fourth instars of Cx tigripes are the most voracious of all the stages and are better adapted for catching and consuming all stages of mosquito larvae. The mean number of mosquito larvae consumed in 24 hours increased with increasing prey density. When offered a mixture of different prey species and larval stages, Cx tigripes larvae consistently selected 4th instars of mosquitoes over pupae and preferred Acdes negypti larvae to the larvae of Cx qiiinquefasciatns and Anopheles gambiae. Prey size, density and mobility were also found to influence prey selection by Cx tigripes. ©2000ICIPE.