Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/6/2007
Publication Date: 7/31/2007
Citation: Legaspi, J.C. 2007. Life table analysis for cactoblastis cactorum immatures and adults under five different constant temperatures. Meeting Abstract. Interpretive Summary:
Technical Abstract: The cactus moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) was reported in Florida in 1989, and is expanding its geographical range in the United States to threaten Opuntia cactus in the southwestern states and Mexico where it is an important economic crop. Laboratory life history studies were conducted at 18, 22, 26, 30 and 34 ºC to understand its biology and develop strategies for control. Duration of immature stages was generally longest at 18, declining at 22 and shortest at 26, 30 and 34 ºC. Total immature development time from eggs to pupae was about 180 days at 18, 116 at 22 and ranged from 65 to 72 days at 26 to 34 ºC. Development rate for egg to pupal stages was estimated using the logisitic equation: rate = 0.0165/(1 + (T/20.7093)-5.8823). Percentage survival of immatures was usually lowest at the temperature extremes tested (18 and 34 ºC), but did not differ between the sexes. Estimated lower developmental threshold temperature was 13.3 ºC, resulting in estimated degree days for development from about 845 at 18 ºC to 1387 at 34 ºC. In general, pupal weights declined with increasing temperature, and were always lower in males than in females. Female adult survivorship was longest at 18 ºC, and shortest at 34 ºC, with the other treatments clustered between the temperature extremes. The highest reproductive values were found at 30 ºC, which indicates an approximate optimal temperature. Net reproductive rate (R0), gross reproductive rate (GRR), generation time (T), intrinsic rate of increase (r), finite rate of increase ('), and doubling time ( DT) were 43.68 &/&, 44.02 &/&, 67.14 d, 0.0562 &/&/d, 1.058 & /&/d, and 12.33 d, respectively. An oviposition rate surface describing mean oviposition rate as a function of time and temperature was: eggs = (-11.241 + 0.854T) d exp (-0.020Td).