Population dynamics of the sugarcane borer, Eldana saccharina Walker (Lepidoptera: Pyralidae), in Natal, South Africa

1989 ◽  
Vol 79 (1) ◽  
pp. 61-80 ◽  
Author(s):  
P. R. Atkinson ◽  
A. J. M. Carnegie
Keyword(s):  
South Africa ◽  
Population Dynamics ◽  
Predictive Model ◽  
Population Change ◽  
Lower Mortality ◽  
Eldana Saccharina ◽  
Natural Mortality ◽  
Light Traps ◽  
Climatic Indices ◽  
Lepidoptera Pyralidae

AbstractInfestations of the sugarcane pest Eldana saccharina Walker have been consistently serious in one part of the cane-growing belt of Natal, South Africa. Mortality in this region over seven years was estimated from moth catches in light traps, checked against population change measured from extensive larval counts, and plotted against climatic indices. The object was to construct a predictive model to illustrate mortality in other regions of the cane belt, to which infestations have spread in recent years. The spread southwards along the coast did not seem to have resulted from a decrease in natural mortality, but the spread to higher altitudes appeared to be due to lower mortality associated with warmer and drier years. The phenology of the insect and the effect of the annual harvesting cycle on phenology are discussed.

A new species of Tachinidae (Diptera) parasitic on the sugarcane borer Eldana saccharina (Lepidoptera: Pyralidae), in Natal, South Africa

1991 ◽  
Vol 81 (2) ◽  
pp. 133-136 ◽  
Author(s):  
D.A. Barraclough
Keyword(s):  
South Africa ◽  
New Species ◽  
Eldana Saccharina ◽  
Cyperus Papyrus ◽  
Sugarcane Borer ◽  
North Eastern ◽  
Lepidoptera Pyralidae ◽  
A New Species

AbstractSchembria eldana, a new species of goniine Tachinidae, is described (both sexes) from north-eastern Natal, South Africa, where it is parasitic on larvae of the sugarcane borer, Eldana saccharina Walker, in Cyperus papyrus umbels. The genus Schembria Rondani was previously known only from two females of S. meridionalis Rondani from Malta and Israel.

scholarly journals Evolved variation in cold tolerance among populations of Eldana saccharina (Lepidoptera: Pyralidae) in South Africa

2014 ◽  
Vol 27 (6) ◽  
pp. 1149-1159 ◽  
Author(s):  
E. Kleynhans ◽  
K. A. Mitchell ◽  
D. E. Conlong ◽  
J. S. Terblanche
Keyword(s):  
South Africa ◽  
Cold Tolerance ◽  
Eldana Saccharina ◽  
Lepidoptera Pyralidae

scholarly journals Population dynamics of Eldana saccharina Walker (Lepidoptera: Pyralidae): application of a biophysical model to understand phenological variation in an agricultural pest

2017 ◽  
Vol 108 (3) ◽  
pp. 283-294 ◽  
Author(s):  
E. Kleynhans ◽  
M.G. Barton ◽  
D.E. Conlong ◽  
J.S. Terblanche
Keyword(s):  
South Africa ◽  
Population Dynamics ◽  
Integrated Pest Management ◽  
Pest Management ◽  
Life Stage ◽  
Management Strategies ◽  
Biophysical Model ◽  
Eldana Saccharina ◽  
Pest Population ◽  
Model Predictions

AbstractUnderstanding pest population dynamics and seasonal phenology is a critical component of modern integrated pest-management programs. Accurate forecasting allows timely, cost-effective interventions, including maximum efficacy of, for example, biological control and/or sterile insect technique. Due to the variation in life stage-related sensitivity toward climate, insect pest population abundance models are often not easily interpreted or lack direct relevance to management strategies in the field. Here we apply a process-based (biophysical) model that incorporates climate data with life stage-dependent physiology and life history to attempt to predict Eldana saccharina life stage and generation turnover in sugarcane fields. Fitness traits are modelled at two agricultural locations in South Africa that differ in average temperature (hereafter a cold and a warm site). We test whether the life stage population structures in the field entering winter and local climate during winter directly affect development rates, and therefore interact to determine the population dynamics and phenological responses of E. saccharina in subsequent spring and summer seasons. The model predicts that: (1) E. saccharina can cycle through more generations at the warm site where fewer hours of cold and heat stress are endured, and (2) at the cold site, overwintering as pupae (rather than larvae) confer higher relative fitness and fecundity in the subsequent summer adult moths. The model predictions were compared with a large dataset of field observations from scouting records. Model predictions for larval presence (or absence) generally overlapped well with positive (or negative) scout records. These results are important for integrated pest management strategies by providing a useful foundation for future population dynamics models, and are applicable to a variety of agricultural landscapes, but especially the sugarcane industry of South Africa.

scholarly journals Increasing frequency of low summer precipitation synchronizes dynamics and compromises metapopulation stability in the Glanville fritillary butterfly

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150173 ◽  
Author(s):  
Ayco J. M. Tack ◽  
Tommi Mononen ◽  
Ilkka Hanski
Keyword(s):  
Population Dynamics ◽  
Population Change ◽  
Temporal Dynamics ◽  
Summer Precipitation ◽  
Life History Stage ◽  
General Effect ◽  
Spatial Synchrony ◽  
Glanville Fritillary Butterfly ◽  
Spatio Temporal

Climate change is known to shift species' geographical ranges, phenologies and abundances, but less is known about other population dynamic consequences. Here, we analyse spatio-temporal dynamics of the Glanville fritillary butterfly ( Melitaea cinxia ) in a network of 4000 dry meadows during 21 years. The results demonstrate two strong, related patterns: the amplitude of year-to-year fluctuations in the size of the metapopulation as a whole has increased, though there is no long-term trend in average abundance; and there is a highly significant increase in the level of spatial synchrony in population dynamics. The increased synchrony cannot be explained by increasing within-year spatial correlation in precipitation, the key environmental driver of population change, or in per capita growth rate. On the other hand, the frequency of drought during a critical life-history stage (early larval instars) has increased over the years, which is sufficient to explain the increasing amplitude and the expanding spatial synchrony in metapopulation dynamics. Increased spatial synchrony has the general effect of reducing long-term metapopulation viability even if there is no change in average metapopulation size. This study demonstrates how temporal changes in weather conditions can lead to striking changes in spatio-temporal population dynamics.

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