LIFE-TABLE PARAMETERS OF SPIDER MITE Tetranychus ludeni Zacher (ACARI: TETRANYCHIDAE) ON Amaranthus tricolor L.
K. P. BETTY
Department of Botany, Sacred Heart College, Chalakudy, Kerala-680 307, India.
SANGEETHA G. KAIMAL *
Department of Zoology, Providence Women’s College, Calicut, Kerala-673 009, India.
*Author to whom correspondence should be addressed.
Abstract
Studies on the life table parameters of the spider mite, Tetranychus ludeni Zacher infesting Amaranthus tricolor was initiated in the laboratory following detached leaf culture method at 30 + 5oC and 70 + 2% RH. The respective durations recorded for pre-oviposition period, oviposition period and post-oviposition period were 0.75 + 2, 10.5 + 0.8 and 0.75 + 2 days respectively. The total number of eggs laid by an adult female averaged 91.65 + 3.9 eggs. Life span was recorded to be 11.75 + 0.7 days. Durations of both sexual and parthenogenetic reproduction were 10.04 + 0.28 days and 9.65 + 0.20 days respectively. Shorter duration of development was observed for parthenogenetic development in comparison to that of sexual reproduction. Male:female sex ratio was recorded to be 1-2: 10. A cognitive aspect that reflected was the addition of a new host plant to the so far enlisted hosts for the mite, T. ludeni.
Keywords: Amaranthus tricolor, spider mite, T. ludeni, moulting, longevity and reproduction