The capacity for increase at a low temperature of several Australian populations of <i>Sitophilus oryzae</i> (L.)

Evans, D. E.

doi:10.1111/j.1442-9993.1977.tb01127.x

Cited by 29 publications

(33 citation statements)

References 21 publications

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“…However, taking observed median longevities for adult S. oryzae of 37 weeks at 18°C (personal observation) and 17 weeks at 29°C (Birch 1953), it may be predicted by thermal summation that longevity at 15 C should be 52.3 weeks. This value is very close to that observed (Evans 1977a) and points to the conclusion that exposure to 15 C is not debihtating, at least in terms of longevity, to adult S. oryzae.…”

supporting

confidence: 89%

Some aspects of acclimation to low temperatures in the grain weevils Sitophilus oryzae (L.) and S. granarius (L.)

Evans

1977

Australian Journal of Ecology

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The ability of Sitophilus oryzae (L.) and S. granarius (L.) to acclimate when transferred from 27 C, a near optimal temperature, to 15 C, a marginal temperature, was examined in terms of chill-coma temperature, dispersal, oxygen consumption and rate of oviposition.The chill-coma temperature of S. oryzae was higher and the increment of acclimation less than that of S. granarius. Acclimation, although well advanced after 2 weeks after transfer, took more than 4 weeks to complete. Re-acclimation after the reciprocal transfer took only 2 weeks.The dispersal of S. oryzae held at 15 and 27 C prior to testing differed when the weevils were released in wheat at 27 C but not when released at 15°C. Cold-acclimated S. granarius dispersed less than warmacclimated weevils when released in wheat at both 15and27°C.The activity oxygen consumption of coldacclimated weevils was less than that of warmacclimated weevils. Inverse-shifts of acutely determined R-T relationships appeared more significant than changes in temperature sensitivity. Acclimation to 15°C took 8-10 days and re-acclimation to 27 C about 6-8 days. S. oryzae consumed less oxygen per unit of weight than S. granarius but was more temperature sensitive. Resting oxygen consumption, which was less temperature sensitive than activity consumption, also exhibited inverse acclimation in both species.S. granarius showed evidence of inverse acclimation of oviposition rate after acclimation at 15°C. 20

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supporting

confidence: 89%

Some aspects of acclimation to low temperatures in the grain weevils Sitophilus oryzae (L.) and S. granarius (L.)

Evans

1977

Australian Journal of Ecology

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“…The comparison of the capacity for increase (r^) of the foreign and Australian populations was founded on concepts discussed by Evans (1977a). The experimental methods for determining the various components of r^, fertility at a favourable temperature, body weight and median chill-coma temperatures were those described by Evans (1977a, c).…”

Section: Methodsmentioning

confidence: 99%

“…The fertility of the populations at 27°C, an optimal temperature, was established for eighteen individual pairs of 2-week old weevils of each population as described by Evans (1977a). The body weights of fifteen live females of each population were determined individually.…”

Section: Methodsmentioning

confidence: 99%

A comparison of the capacity for increase at a low temperature of foreign and Australian populations of Sitophilus oryzae (L.) and S. granarius (L.)

Evans

1979

Austral Ecol

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The capacity for increase (ij of three populations of S. oryzae and three populations of S. granarius from Great Britain and Canada was determined over 15 and 24 weeks respectively at 15°C in wheat of 14% moisture content. The fertility of these populations at 27°C, their body weight and chill-coma threshold was also measured.With both S. oryzae and S. granarius, values of r^ for the foreign populations fell within the range previously observed when several Australian populations were reared under the same conditions. The cohort generation times (Jc) of the foreign S. oryzae populations were significantly shorter than those of the Australian populations because of the shorter immature development periods (B) of the former. Two of the foreign S. granarius populations had lower values for D than all but one of their Australian counterparts but their values of T^ were within the range previously observed for Australian weevils. When the Australian and foreign populations were considered together, the value of Xc was more strongly correlated with fertility at 27°, an optimal temperature, than with body weight in both S. oryzae and S. granarius. With S. oryzae, r^ was correlated with the chill-coma threshold of cold-acclimated weevils only. There were no correlations between r^. and chill-coma thresholds in S. granarius. It was concluded that the observed differences in r^ were related to differences in the vigour of the populations rather than to physiological differences in cold-tolerance.The likelihood of grain weevils becoming cold-tolerant as a result of grain aeration is discussed and the practical significance of differences in r^ considered.

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“…When reared on wheat, the capacity for increase of S. o y m e is greater than that of both S. zeumuis [26] and S. grunurius [27,28]. In addition, S. oryzue is more efficient than S. grunurius in utilizing whole wheat [4,29] or a starchbased meridic diet [30] as food sources and out-competes S. granarius in competition experiments [31].…”

Section: Adaptive Significance Of Amylase Levels In Sitophilusmentioning

confidence: 99%

Purification, partial characterization, and postembryonic levels of amylases from Sitophilus oryzae and Sitophilus granarius

Baker

Woo

1985

Arch Insect Biochem Physiol

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Amylases from adults of Sitophilus oryzae (L.) and S. granarius (L.) were purified by using a sequential procedure of ammonium sulfate precipitation, glycogen-complex formation, and ion exchange chromatography. Amylase of S. oryaze was purified 47.4-fold to a specific activity of 478 unitdmg protein.One amylase unit equals 1 mg maltose hydrate producedlmin at 3OOC. Amylase of S. granarius was purified 85.4fold to a specific activity of 453 unitshg protein. Amylase of S. oryzae had a Km of 0.173% for soluble starch and consisted of two anionic isozyrnes with isoelectric points of pH 3.70 and pH 3.76. Amylase of S. granarius had a Km of 0.078% for starch and was a single protein with an isoelectric point of pH 3.76. Purified amylases of both species had molecular weights of 56,000 estimated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis, were activated by chloride, and had double energies of activation calculated from Arrhenius plots. Based on fresh weights of adults feeding on whole wheat through 10 weeks of age, S. oryzae contained three-fold and eight-fold more amylase than S. granarius and S.zeamais Motschulsky, respectively. High amylase levels in S. oryzae may provide this species with an adaptive advantage when feeding on cereals containing naturally occurring amylase inhibitors.

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The capacity for increase at a low temperature of several Australian populations of Sitophilus oryzae (L.)

Cited by 29 publications

References 21 publications

Some aspects of acclimation to low temperatures in the grain weevils Sitophilus oryzae (L.) and S. granarius (L.)

Some aspects of acclimation to low temperatures in the grain weevils Sitophilus oryzae (L.) and S. granarius (L.)

A comparison of the capacity for increase at a low temperature of foreign and Australian populations of Sitophilus oryzae (L.) and S. granarius (L.)

Purification, partial characterization, and postembryonic levels of amylases from Sitophilus oryzae and Sitophilus granarius

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