Influence of Temperature on the Interaction for Resource Utilization between Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), and a Community of Lepidopteran Maize Stemborers Larvae

Abstract

Intra- and interspecific interactions within communities of species that utilize the same resources are characterized by competition or facilitation. The noctuid stemborers, Busseola fusca and Sesamia calamistis, and the crambid stemborer, Chilo partellus were the most important pests of maize in sub-Saharan Africa before the recent “invasion” of fall armyworm (FAW), Spodoptera frugiperda, which currently seriously limits maize yields in Africa. This new pest is interacting with the stemborer community at the larval stage in the use of maize resources. From previous works on the influence of temperature on the larval intra- and interspecific resources utilization within the community of Lepidoptera stemborers involving B. fusca, S. calamistis, and C. partellus, there is a need to update these studies by adding the new pest, S. frugiperda, in order to understand the effect of temperature on the larval interactions of all these four species under the context of climate change. The influence of temperature on intra- and interspecific larval interactions was studied using artificial stems kept at different constant temperatures (15 °C, 20 °C, 25 °C, and 30 °C) in an incubator and assessing survival and relative growth rates of each species in single and multi-species experiments. After the inclusion of FAW into the experiments, with regard to relative growth rates, both intra- and interspecific competition was observed among all four species. With regard to survival rates, cannibalism can also explain the intra- and interspecific interactions observed among all four species. Interspecific competition was stronger between the stemborers than between the FAW and the stemborers. Similar to lepidopteran stemborers, temperature affected both survival and relative growth rates of the FAW as well. Regardless of the temperature, C. partellus was superior in interspecific interactions shown by higher relative growth and survival rates. The results suggest that the FAW will co-exist with stemborer species along entire temperature gradient, though competition and/or cannibalism with them is weak. In addition, temperature increases caused by climate change is likely to confer an advantage to C. partellus over the fall armyworm and the other noctuids.

Agronomic Factors Influencing Fall Armyworm (Spodoptera frugiperda) Infestation and Damage and Its Co-Occurrence with Stemborers in Maize Cropping Systems in Kenya

“…Field surveys recorded higher FAW numbers (eggs and larvae) than combined numbers of cereal stemborers, both native ( B. fusca and S. calamisitis ) and exotic C. partellus on maize plants. Although surveys conducted just at the beginning of FAW invasion in Kenya revealed a possible co-existence of FAW with stemborers [ 13 , 59 ], our results demonstrate that within an approximately four-year period since its invasion in Kenya, FAW has become the dominant lepidopteran pest species in local maize fields where they cohabitate with stemborers. Before FAW invasion, stemborers were the dominant lepidopteran pests in maize fields in Kenya, with C. partellus being dominant in low-altitude zones, while B. fusca dominated the high-altitude zones [ 60 , 61 , 62 ].…”

“…Fall armyworm cause similar damages and occupy the same ecological niches as lepidopteran stemborers, such as B. fusca , S. calamistis and C. partellus [ 12 ]. These lepidopterans are interacting with and amongst each other, especially at the larval stage in the utilization of crop resources, being mainly maize, which is their preferred host plant [ 12 , 13 ]. Given that these herbivore pests have similar feeding guild, host plant and phenological characteristics [ 14 , 15 ], competitive interspecific interactions are likely to occur.…”

Larval dispersal of the invasive fall armyworm, Spodoptera frugiperda, the exotic stemborer Chilo partellus, and indigenous maize stemborers in Africa

“…Recently, the fall armyworm (FAW), Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), invaded sub‐Saharan Africa, where it has seriously limited maize yields (Goergen et al, 2016; Cock et al, 2017; Fotso Kuate et al, 2019). Recent observations indicate that it closely interacts with maize stemborer communities (Sokame et al, 2020) and might also displace the stemborers. Among these species, the females of B. fusca and S. calamistis lay their eggs between the leaf sheath and the stem of the plant, protected against environmental influences and natural enemies, whereas C. partellus and S. frugiperda deposit eggs directly on leaf surfaces, which makes them disperse faster and more efficiently between plants (Pitre et al, 1983; Polaszek, 1998).…”

Cannibalism and intraguild predation involved in the intra- and inter-specific interactions of the invasive fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) and lepidopteran maize stemborers

“…This gives an advantage of FAW over maize stemborers resulting of an overall reduction in stemborer density generally observed in maize elds in Kenya at the beginning of the season (Sokame et al 2021a), a displacement of some of them to other cereals in Uganda (Hailu et al 2021). However, the speci city of FAW to feed on leaves and stemborers to plant stems in late instars might result in the co-existence fall armyworm with stemborer species in maize agroecological zones (Sokame et al 2020(Sokame et al , 2021b. Therefore, the invasion of FAW in Africa constitutes an additional pest to crops in agroecosystems that need to be considered within the context of integrated pest management strategies.…”