Developmental and reproductive biology of a predatory Franklinothrips n. sp (Thysanoptera: Aeolothripidae)

The developmental and reproductive biology of a new species of predatory Franklinothrips was determined in the laboratory at three constant temperatures. At the intermediate experimental temperature (25 degrees C), Franklinothrips n. sp. exhibited the greatest larval to adult survivorship, and mated females produced more progeny of which a greater proportion were female when compared to individuals reared at 20 and 30 degrees C. Analysis of jackknife estimates of net reproduction (R-o), generation times (T-c), intrinsic rate of increase (r(m)), and finite rate of increase (lambda) were all significantly greater at 25 degrees C than corresponding values at 20 and 30 degrees C. Population doubling time (T-d) was significantly lower at 25 degrees C, indicating that population growth is approximately 50% faster at this temperature than at 20 and 30 degrees C. Unmated female Frankli- nothrips n. sp. produce only male offspring, confirming arrhenotoky in this species. At 30 degrees C, 15% of larvae failed to produce silk pupation cocoons and prepupal and pupal stages were observed for cocoonless individuals. This result indicates that Franklinothrips n. sp. has two pupal stages, contradicting earlier speculations about the pupal biology of this genus. Furthermore, at 30 degrees C, 13% of mated females and 33% of unmated females failed to produce viable eggs when reared and maintained at this temperature. (C) 2000 Academic Press.