Fertility Life Table, Population Parameters and Biotic Potential of Helicoverpa gelotopoeon (Dyar) (Lepidoptera: Noctuidae)

Differential Hatching, Development, Oviposition, and Longevity Patterns among Colombian Aedes aegypti Populations

Simple Summary

Aedes aegypti is a mosquito that transmits viruses responsible for several diseases in humans, such as dengue, Zika, and chikungunya. It is crucial to study mosquito populations from different countries and regions because control of disease transmission with insecticides can be more effective if adjusted to each population’s characteristics. For this reason, we determined several features of mosquitoes captured in different cities of Colombia: Neiva, Bello, Itagüí, and Riohacha. These included the length of their lifespan, the number of eggs they lay, and the stages in which they die. We found specific patterns for each population. This knowledge will help control programs determine the optimal times to apply insecticides and make surveillance, as well as the type of insecticide used.

Abstract

Dengue, Zika, and chikungunya are arboviral diseases for which there are no effective therapies or vaccines. The only way to avoid their transmission is by controlling the vector Aedes aegypti, but insecticide resistance limits this strategy. To generate relevant information for surveillance and control mechanisms, we determined life cycle parameters, including longevity, fecundity, and mortality, of Colombian Ae. aegypti populations from four different geographical regions: Neiva, Bello, Itagüí, and Riohacha. When reared at 28 °C, Bello had the shortest development time, and Riohacha had the longest. Each mosquito population had its own characteristic fecundity pattern during four gonotrophic cycles. The survival curves of each population were significantly different, with Riohacha having the longest survival in both males and females and Bello the shortest. High mortality was observed in mosquitoes from Neiva in the egg stage and for Bello in the pupae stage. Finally, when mosquitoes from Neiva and Bello were reared at 35 °C, development times and mortality were severely affected. In conclusion, each population has a unique development pattern with an innate trace in their biological characteristics that confers vulnerability in specific stages of development.

Influence of larval nutrition on biological attributes and reproductive performance in Spodoptera frugiperda (Lepidoptera: Noctuidae) under laboratory condition

An artificial diet and a rearing procedure for the polyphagous pest, Spodoptera frugiperda, were developed to facilitate its culturing under laboratory conditions [27 ± 1°C, 65 ± 5% relative humidity and a photoperiod of 14:10 (L:D) h] throughout the year. The efficiency of the diet was assessed through a comparative study with the natural host of the pest, maize. The biological, reproductive and population parameters of the pest on artificial diet were superior, especially the enhanced mean fecundity of 1796 per female which was more than that of the insect reared on its natural host. The meridic diet gave a higher mean pupal weight (0.217 g/pupa) than the natural diet (0.188 g/pupa). About 81.8% of neonates completed their developmental cycle on artificial diet and emerged as healthy adults, compared to only 57.5% normal adult emergence on the natural diet. On observation, there were 3678 and 3551 eupyrene sperm bundles in the adults emerged from larvae reared on artificial diet and natural diet, respectively. The net reproductive rate () for adults reared on artificial diet was 945.26, it being 703.7 for adults reared on a natural diet. With a sex ratio of 0.55, the biotic potential of S. frugiperda reared on artificial diet was 5.104 × 1028, which is more than that of natural diet (5.740 × 1026). The fertility life table constructed in the present study can play a significant role in predicting population dynamics, which will further help in developing an effective integrated pest management and the developed meridic diet with rearing procedure will be helpful in insecticide resistance monitoring programmes for this folivorous pest.